"""API routes for File Manager (Library) functionality."""

import base64
import binascii
import contextlib
import hashlib
import logging
import os
import re
import shutil
import uuid
import zipfile
from datetime import datetime, timezone
from pathlib import Path

from fastapi import APIRouter, Depends, File, HTTPException, Query, Response, UploadFile
from fastapi.responses import FileResponse as FastAPIFileResponse
from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import selectinload

from backend.app.core.auth import (
    RequireCameraStreamTokenIfAuthEnabled,
    require_ownership_permission,
    require_permission_if_auth_enabled,
)
from backend.app.core.config import settings as app_settings
from backend.app.core.database import get_db
from backend.app.core.permissions import Permission
from backend.app.models.archive import PrintArchive
from backend.app.models.library import LibraryFile, LibraryFolder
from backend.app.models.print_queue import PrintQueueItem
from backend.app.models.project import Project
from backend.app.models.user import User
from backend.app.schemas.library import (
    AddToQueueError,
    AddToQueueRequest,
    AddToQueueResponse,
    AddToQueueResult,
    BatchThumbnailRequest,
    BatchThumbnailResponse,
    BatchThumbnailResult,
    BulkDeleteRequest,
    BulkDeleteResponse,
    ExternalFolderCreate,
    FileDuplicate,
    FileListResponse,
    FileMoveRequest,
    FilePrintRequest,
    FileResponse as FileResponseSchema,
    FileUpdate,
    FileUploadResponse,
    FolderCreate,
    FolderResponse,
    FolderTreeItem,
    FolderUpdate,
    ZipExtractError,
    ZipExtractResponse,
    ZipExtractResult,
)
from backend.app.schemas.slicer import SliceRequest, SliceResponse
from backend.app.services.archive import ThreeMFParser
from backend.app.services.stl_thumbnail import generate_stl_thumbnail
from backend.app.utils.threemf_tools import (
    extract_nozzle_mapping_from_3mf,
    extract_plate_extruder_set_from_3mf,
    extract_project_filaments_from_3mf,
)

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/library", tags=["library"])


def get_library_dir() -> Path:
    """Get the library storage directory."""
    base_dir = Path(app_settings.archive_dir)
    library_dir = base_dir / "library"
    library_dir.mkdir(parents=True, exist_ok=True)
    return library_dir


def get_library_files_dir() -> Path:
    """Get the directory for library files."""
    files_dir = get_library_dir() / "files"
    files_dir.mkdir(parents=True, exist_ok=True)
    return files_dir


def get_library_thumbnails_dir() -> Path:
    """Get the directory for library thumbnails."""
    thumbnails_dir = get_library_dir() / "thumbnails"
    thumbnails_dir.mkdir(parents=True, exist_ok=True)
    return thumbnails_dir


def to_relative_path(absolute_path: Path | str) -> str:
    """Convert an absolute path to a path relative to base_dir for storage."""
    if not absolute_path:
        return ""
    abs_path = Path(absolute_path)
    base_dir = Path(app_settings.base_dir)
    try:
        return str(abs_path.relative_to(base_dir))
    except ValueError:
        # Path is not under base_dir, return as-is (shouldn't happen normally)
        return str(abs_path)


def to_absolute_path(relative_path: str | None) -> Path | None:
    """Convert a relative path (from database) to an absolute path for file operations."""
    if not relative_path:
        return None
    path = Path(relative_path)
    # Handle already-absolute paths verbatim (backwards compatibility during migration).
    # Legacy DB rows may store absolute paths that predate the base_dir layout; the
    # traversal guard below only applies to relative paths coming from user input.
    if path.is_absolute():
        return path.resolve()
    base = Path(app_settings.base_dir).resolve()
    resolved = (base / relative_path).resolve()
    # Guard against path traversal — resolved path must stay inside base_dir.
    # Use is_relative_to() to avoid the /data/app vs /data/app_evil prefix confusion
    # that a plain startswith(str(base)) check would miss.
    if not resolved.is_relative_to(base):
        raise ValueError(f"Path escapes base directory: {relative_path!r}")
    return resolved


def calculate_file_hash(file_path: Path) -> str:
    """Calculate SHA256 hash of a file."""
    sha256_hash = hashlib.sha256()
    with open(file_path, "rb") as f:
        for byte_block in iter(lambda: f.read(4096), b""):
            sha256_hash.update(byte_block)
    return sha256_hash.hexdigest()


def _resolve_upload_destination(target_folder: LibraryFolder | None, filename: str) -> tuple[Path, bool]:
    """Resolve the on-disk destination for an uploaded file.

    Non-external target: returns ``(<library_files_dir>/<uuid><ext>, False)``.
    Writable external target: writes to ``<external_path>/<filename>``
    (preserves the real filename so the file is recognisable on the mount);
    returns ``(dest, True)``. Raises ``HTTPException`` for read-only external
    folders (403), missing/inaccessible/non-writable external paths (400), and
    filename collisions on the external mount (409). See #1112 — previously
    uploads to writable external folders were silently misrouted to the
    internal library dir.
    """
    if target_folder is not None and target_folder.is_external:
        if target_folder.external_readonly:
            raise HTTPException(status_code=403, detail="Cannot upload to a read-only external folder")
        if not target_folder.external_path:
            raise HTTPException(status_code=400, detail="External folder has no configured path")
        ext_dir = Path(target_folder.external_path)
        if not ext_dir.exists() or not ext_dir.is_dir():
            raise HTTPException(
                status_code=400,
                detail=f"External path is not accessible: {target_folder.external_path}",
            )
        if not os.access(ext_dir, os.W_OK):
            raise HTTPException(
                status_code=400,
                detail=f"External path is not writable: {target_folder.external_path}",
            )
        # Guard against path-traversal via a pathological filename — join then
        # verify the resolved destination is still inside the external dir.
        dest = (ext_dir / filename).resolve()
        try:
            dest.relative_to(ext_dir.resolve())
        except ValueError:
            raise HTTPException(status_code=400, detail="Invalid filename")
        if dest.exists():
            raise HTTPException(
                status_code=409,
                detail=f"A file named {filename!r} already exists in the external folder",
            )
        return dest, True
    ext = os.path.splitext(filename)[1].lower()
    return get_library_files_dir() / f"{uuid.uuid4().hex}{ext}", False


def _stored_file_path(abs_path: Path, is_external: bool) -> str:
    """Produce the value to persist in ``LibraryFile.file_path``.

    External files store the absolute mount path directly (same as scan does),
    so ``to_absolute_path`` round-trips through its ``is_absolute()`` fast
    path. Managed files store a path relative to ``base_dir`` for portability.
    """
    return str(abs_path) if is_external else to_relative_path(abs_path)


class _MoveSkip(Exception):
    """Signalled by ``_move_file_bytes`` to skip a file with a user-visible reason.

    Carries an optional `code` for machine-friendly grouping (the
    front-end can localise it) and a fallback English `reason` for logs.
    """

    def __init__(self, code: str, reason: str):
        super().__init__(reason)
        self.code = code
        self.reason = reason


def _resolve_source_disk_path(file: LibraryFile) -> Path | None:
    """Return the absolute on-disk path for an existing LibraryFile, or None
    if it can't be located (legacy DB row, deleted file, etc.)."""
    if file.is_external:
        return Path(file.file_path) if file.file_path else None
    return to_absolute_path(file.file_path)


def _move_file_bytes(file: LibraryFile, target_folder: LibraryFolder | None) -> str:
    """Physically relocate `file`'s bytes to match `target_folder`.

    Used by the move endpoint when source/target straddle the
    managed↔external boundary (#1112 follow-up — the prior implementation
    updated the DB row's ``folder_id`` but never moved the bytes, so a
    file moved to an external SMB folder showed up in Bambuddy's UI but
    not on the NAS).

    Returns the new ``file_path`` value to persist (relative for managed
    targets, absolute for external targets — matches the upload + scan
    paths). Raises ``_MoveSkip`` for any condition that would make the
    move unsafe (target unwritable, filename collision, source missing).

    The copy-then-unlink ordering means a partial copy followed by a
    failed unlink leaves both the source and the dest on disk — better
    than the symmetric "rename or move" which would lose the source if
    the target write didn't complete on a flaky mount. The DB row stays
    pointed at the source until the caller commits the new ``file_path``.
    """
    src = _resolve_source_disk_path(file)
    if not src or not src.exists():
        raise _MoveSkip("source_missing", "source file missing on disk")

    target_is_external = target_folder is not None and target_folder.is_external

    if target_is_external:
        if target_folder.external_readonly:
            # Already blocked at top level, but defence-in-depth.
            raise _MoveSkip("target_readonly", "target external folder is read-only")
        if not target_folder.external_path:
            raise _MoveSkip("target_misconfigured", "target external folder has no path")
        ext_dir = Path(target_folder.external_path)
        if not ext_dir.exists() or not ext_dir.is_dir():
            raise _MoveSkip("target_inaccessible", f"target path not accessible: {ext_dir}")
        if not os.access(ext_dir, os.W_OK):
            raise _MoveSkip("target_unwritable", f"target path not writable: {ext_dir}")
        dest = (ext_dir / file.filename).resolve()
        try:
            dest.relative_to(ext_dir.resolve())
        except ValueError:
            raise _MoveSkip("invalid_filename", f"unsafe filename: {file.filename!r}") from None
        if dest.exists():
            raise _MoveSkip("name_collision", f"a file named {file.filename!r} already exists in target")
        try:
            shutil.copy2(src, dest)
        except OSError as e:
            # Clean up partial dest so a retry can succeed.
            with contextlib.suppress(OSError):
                dest.unlink(missing_ok=True)
            raise _MoveSkip("copy_failed", f"copy failed: {e}") from e
    else:
        # → managed (root or non-external folder): generate a fresh UUID
        # filename in the internal store so we don't collide with another
        # file that happens to share `filename`.
        ext = src.suffix.lower()
        dest = get_library_files_dir() / f"{uuid.uuid4().hex}{ext}"
        try:
            shutil.copy2(src, dest)
        except OSError as e:
            with contextlib.suppress(OSError):
                dest.unlink(missing_ok=True)
            raise _MoveSkip("copy_failed", f"copy failed: {e}") from e

    # Copy succeeded — unlink the original. A failure here leaves an
    # orphan on disk but the DB row is consistent against the new dest.
    try:
        src.unlink(missing_ok=True)
    except OSError as e:
        logger.warning(
            "Move: copied %s → %s but couldn't remove source: %s",
            src,
            dest,
            e,
        )

    return _stored_file_path(dest, is_external=target_is_external)


def _clean_3mf_metadata(obj):
    """Strip bytes and thumbnail-carrier keys so the payload is JSON-storable.

    Shared by ``upload_file`` and :func:`save_3mf_bytes_to_library` — the
    ``ThreeMFParser`` output embeds the thumbnail bytes under
    ``_thumbnail_data``/``_thumbnail_ext`` and may also include raw bytes in
    other fields, none of which can be JSON-encoded.
    """
    if isinstance(obj, dict):
        return {
            k: _clean_3mf_metadata(v)
            for k, v in obj.items()
            if not isinstance(v, bytes) and k not in ("_thumbnail_data", "_thumbnail_ext")
        }
    if isinstance(obj, list):
        return [_clean_3mf_metadata(i) for i in obj if not isinstance(i, bytes)]
    if isinstance(obj, bytes):
        return None
    return obj


async def save_3mf_bytes_to_library(
    db: AsyncSession,
    *,
    file_bytes: bytes,
    filename: str,
    folder_id: int | None = None,
    source_type: str | None = None,
    source_url: str | None = None,
    owner_id: int | None = None,
) -> tuple[LibraryFile, bool]:
    """Save a 3MF blob into the library and return ``(library_file, was_existing)``.

    Used by routes that receive a 3MF in-process rather than as a multipart
    upload (currently: MakerWorld import; reusable for any future source that
    fetches bytes server-side). Deduplicates by ``source_url`` when provided —
    if a LibraryFile with the same source_url already exists, the existing
    row is returned and the bytes are NOT re-saved (MakerWorld signed URLs
    change each download, so hash-based dedupe alone would miss re-imports).

    Parses 3MF metadata + thumbnail the same way the multipart upload route
    does, via :class:`ThreeMFParser`. Paths are stored as relative so the
    library is portable across installs.
    """
    # Source-URL-based dedupe: return the existing row untouched.
    if source_url:
        existing = await db.execute(LibraryFile.active().where(LibraryFile.source_url == source_url).limit(1))
        existing_row = existing.scalar_one_or_none()
        if existing_row is not None:
            return existing_row, True

    # Persist bytes to disk under a UUID-scoped filename; keep the original
    # extension so downstream logic (ThreeMFParser, thumbnail viewer) works.
    ext = os.path.splitext(filename)[1].lower() or ".3mf"
    unique_filename = f"{uuid.uuid4().hex}{ext}"
    file_path = get_library_files_dir() / unique_filename
    with open(file_path, "wb") as fh:
        fh.write(file_bytes)

    file_hash = calculate_file_hash(file_path)

    # Extract metadata + thumbnail from the 3MF.
    metadata: dict | None = None
    thumbnail_path: str | None = None
    if ext == ".3mf":
        try:
            parser = ThreeMFParser(str(file_path))
            raw_metadata = parser.parse()
            thumb_data = raw_metadata.get("_thumbnail_data")
            thumb_ext = raw_metadata.get("_thumbnail_ext", ".png")
            if thumb_data:
                thumbs_dir = get_library_thumbnails_dir()
                thumb_filename = f"{uuid.uuid4().hex}{thumb_ext}"
                thumb_path = thumbs_dir / thumb_filename
                with open(thumb_path, "wb") as fh:
                    fh.write(thumb_data)
                thumbnail_path = str(thumb_path)
            metadata = _clean_3mf_metadata(raw_metadata) or None
        except Exception as exc:
            # Matches the multipart upload route's behaviour — a bad 3MF should
            # still land in the library so the user can see / delete it rather
            # than failing the whole request.
            logger.warning("Failed to parse 3MF %s: %s", filename, exc)

    library_file = LibraryFile(
        folder_id=folder_id,
        filename=filename,
        file_path=to_relative_path(file_path),
        file_type=ext[1:] if ext else "unknown",
        file_size=len(file_bytes),
        file_hash=file_hash,
        thumbnail_path=to_relative_path(thumbnail_path) if thumbnail_path else None,
        file_metadata=metadata,
        source_type=source_type,
        source_url=source_url,
        created_by_id=owner_id,
    )
    db.add(library_file)
    await db.commit()
    await db.refresh(library_file)
    return library_file, False


def extract_gcode_thumbnail(file_path: Path) -> bytes | None:
    """Extract embedded thumbnail from gcode file.

    Supports PrusaSlicer/BambuStudio format:
    ; thumbnail begin WxH SIZE
    ; base64data...
    ; thumbnail end
    """
    try:
        thumbnail_data = None
        in_thumbnail = False
        thumbnail_lines = []
        best_size = 0

        with open(file_path, errors="ignore") as f:
            # Only read first 50KB for performance (thumbnails are at the start)
            content = f.read(50000)

        for line in content.split("\n"):
            line = line.strip()

            # Check for thumbnail start
            if line.startswith("; thumbnail begin"):
                in_thumbnail = True
                thumbnail_lines = []
                # Parse dimensions: "; thumbnail begin 300x300 12345"
                match = re.search(r"(\d+)x(\d+)", line)
                if match:
                    width = int(match.group(1))
                    # Prefer larger thumbnails (up to 300px)
                    if width > best_size and width <= 300:
                        best_size = width
                continue

            # Check for thumbnail end
            if line.startswith("; thumbnail end"):
                if in_thumbnail and thumbnail_lines:
                    try:
                        # Decode the base64 data
                        b64_data = "".join(thumbnail_lines)
                        decoded = base64.b64decode(b64_data)
                        # Only keep if this is the best size or first valid thumbnail
                        if thumbnail_data is None or best_size > 0:
                            thumbnail_data = decoded
                    except (binascii.Error, ValueError):
                        pass  # Skip thumbnail with invalid base64 data
                in_thumbnail = False
                thumbnail_lines = []
                continue

            # Collect thumbnail data
            if in_thumbnail and line.startswith(";"):
                # Remove the leading "; " or ";"
                data_line = line[1:].strip()
                if data_line:
                    thumbnail_lines.append(data_line)

        return thumbnail_data
    except Exception as e:
        logger.warning("Failed to extract gcode thumbnail: %s", e)
        return None


def create_image_thumbnail(file_path: Path, thumbnails_dir: Path, max_size: int = 256) -> str | None:
    """Create a thumbnail from an image file.

    For small images, copies directly. For larger images, resizes.
    Returns the thumbnail path or None on failure.
    """
    try:
        from PIL import Image

        thumb_filename = f"{uuid.uuid4().hex}.png"
        thumb_path = thumbnails_dir / thumb_filename

        with Image.open(file_path) as img:
            # Convert to RGB if necessary (for PNG with transparency, etc.)
            if img.mode in ("RGBA", "LA", "P"):
                # Create white background for transparency
                background = Image.new("RGB", img.size, (255, 255, 255))
                if img.mode == "P":
                    img = img.convert("RGBA")
                background.paste(img, mask=img.split()[-1] if img.mode == "RGBA" else None)
                img = background
            elif img.mode != "RGB":
                img = img.convert("RGB")

            # Resize if larger than max_size
            if img.width > max_size or img.height > max_size:
                img.thumbnail((max_size, max_size), Image.Resampling.LANCZOS)

            img.save(thumb_path, "PNG", optimize=True)

        return str(thumb_path)
    except ImportError:
        # PIL not installed, just copy the file if it's small enough
        logger.warning("PIL not installed, copying image as thumbnail")
        try:
            file_size = file_path.stat().st_size
            if file_size < 500000:  # Less than 500KB
                thumb_filename = f"{uuid.uuid4().hex}{file_path.suffix}"
                thumb_path = thumbnails_dir / thumb_filename
                shutil.copy2(file_path, thumb_path)
                return str(thumb_path)
        except OSError:
            pass  # File inaccessible; fall through to return None
        return None
    except Exception as e:
        logger.warning("Failed to create image thumbnail: %s", e)
        return None


# Supported image extensions for thumbnails
IMAGE_EXTENSIONS = {".png", ".jpg", ".jpeg", ".gif", ".webp", ".bmp", ".tiff", ".tif"}


# ============ Folder Endpoints ============


@router.get("/folders", response_model=list[FolderTreeItem])
@router.get("/folders/", response_model=list[FolderTreeItem])
async def list_folders(
    response: Response,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get all folders as a tree structure."""
    # Prevent browser caching of folder list
    response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"

    # Get all folders with project and archive joins
    result = await db.execute(
        select(LibraryFolder, Project.name, PrintArchive.print_name)
        .outerjoin(Project, LibraryFolder.project_id == Project.id)
        .outerjoin(PrintArchive, LibraryFolder.archive_id == PrintArchive.id)
        .order_by(LibraryFolder.name)
    )
    rows = result.all()

    # Get file counts per folder
    file_counts_result = await db.execute(
        select(LibraryFile.folder_id, func.count(LibraryFile.id))
        .where(LibraryFile.folder_id.isnot(None), LibraryFile.deleted_at.is_(None))
        .group_by(LibraryFile.folder_id)
    )
    file_counts = dict(file_counts_result.all())

    # Build tree structure
    folder_map = {}
    root_folders = []

    for folder, project_name, archive_name in rows:
        folder_item = FolderTreeItem(
            id=folder.id,
            name=folder.name,
            parent_id=folder.parent_id,
            project_id=folder.project_id,
            archive_id=folder.archive_id,
            project_name=project_name,
            archive_name=archive_name,
            is_external=folder.is_external,
            external_path=folder.external_path,
            external_readonly=folder.external_readonly,
            file_count=file_counts.get(folder.id, 0),
            children=[],
        )
        folder_map[folder.id] = folder_item

    # Link children to parents
    for folder, _, _ in rows:
        folder_item = folder_map[folder.id]
        if folder.parent_id is None:
            root_folders.append(folder_item)
        elif folder.parent_id in folder_map:
            folder_map[folder.parent_id].children.append(folder_item)

    return root_folders


@router.get("/folders/by-project/{project_id}", response_model=list[FolderResponse])
async def get_folders_by_project(
    project_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get all folders linked to a specific project."""
    result = await db.execute(
        select(LibraryFolder, Project.name)
        .outerjoin(Project, LibraryFolder.project_id == Project.id)
        .where(LibraryFolder.project_id == project_id)
        .order_by(LibraryFolder.name)
    )
    rows = result.all()

    folders = []
    for folder, project_name in rows:
        # Get file count
        file_count_result = await db.execute(
            select(func.count(LibraryFile.id)).where(
                LibraryFile.folder_id == folder.id,
                LibraryFile.deleted_at.is_(None),
            )
        )
        file_count = file_count_result.scalar() or 0

        folders.append(
            FolderResponse(
                id=folder.id,
                name=folder.name,
                parent_id=folder.parent_id,
                project_id=folder.project_id,
                archive_id=folder.archive_id,
                project_name=project_name,
                archive_name=None,
                is_external=folder.is_external,
                external_path=folder.external_path,
                external_readonly=folder.external_readonly,
                external_show_hidden=folder.external_show_hidden,
                file_count=file_count,
                created_at=folder.created_at,
                updated_at=folder.updated_at,
            )
        )

    return folders


@router.get("/folders/by-archive/{archive_id}", response_model=list[FolderResponse])
async def get_folders_by_archive(
    archive_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get all folders linked to a specific archive."""
    result = await db.execute(
        select(LibraryFolder, PrintArchive.print_name)
        .outerjoin(PrintArchive, LibraryFolder.archive_id == PrintArchive.id)
        .where(LibraryFolder.archive_id == archive_id)
        .order_by(LibraryFolder.name)
    )
    rows = result.all()

    folders = []
    for folder, archive_name in rows:
        # Get file count
        file_count_result = await db.execute(
            select(func.count(LibraryFile.id)).where(
                LibraryFile.folder_id == folder.id,
                LibraryFile.deleted_at.is_(None),
            )
        )
        file_count = file_count_result.scalar() or 0

        folders.append(
            FolderResponse(
                id=folder.id,
                name=folder.name,
                parent_id=folder.parent_id,
                project_id=folder.project_id,
                archive_id=folder.archive_id,
                project_name=None,
                archive_name=archive_name,
                is_external=folder.is_external,
                external_path=folder.external_path,
                external_readonly=folder.external_readonly,
                external_show_hidden=folder.external_show_hidden,
                file_count=file_count,
                created_at=folder.created_at,
                updated_at=folder.updated_at,
            )
        )

    return folders


@router.post("/folders", response_model=FolderResponse)
@router.post("/folders/", response_model=FolderResponse)
async def create_folder(
    data: FolderCreate,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPLOAD)),
):
    """Create a new folder."""
    # Verify parent exists if specified
    if data.parent_id is not None:
        parent_result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == data.parent_id))
        if not parent_result.scalar_one_or_none():
            raise HTTPException(status_code=404, detail="Parent folder not found")

    # Verify project exists if specified
    project_name = None
    if data.project_id is not None:
        project_result = await db.execute(select(Project).where(Project.id == data.project_id))
        project = project_result.scalar_one_or_none()
        if not project:
            raise HTTPException(status_code=404, detail="Project not found")
        project_name = project.name

    # Verify archive exists if specified
    archive_name = None
    if data.archive_id is not None:
        archive_result = await db.execute(select(PrintArchive).where(PrintArchive.id == data.archive_id))
        archive = archive_result.scalar_one_or_none()
        if not archive:
            raise HTTPException(status_code=404, detail="Archive not found")
        archive_name = archive.print_name

    folder = LibraryFolder(
        name=data.name,
        parent_id=data.parent_id,
        project_id=data.project_id,
        archive_id=data.archive_id,
    )
    db.add(folder)
    await db.commit()
    await db.refresh(folder)

    return FolderResponse(
        id=folder.id,
        name=folder.name,
        parent_id=folder.parent_id,
        project_id=folder.project_id,
        archive_id=folder.archive_id,
        project_name=project_name,
        archive_name=archive_name,
        is_external=folder.is_external,
        external_path=folder.external_path,
        external_readonly=folder.external_readonly,
        external_show_hidden=folder.external_show_hidden,
        file_count=0,
        created_at=folder.created_at,
        updated_at=folder.updated_at,
    )


@router.get("/folders/{folder_id}", response_model=FolderResponse)
async def get_folder(
    folder_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get a folder by ID."""
    result = await db.execute(
        select(LibraryFolder, Project.name, PrintArchive.print_name)
        .outerjoin(Project, LibraryFolder.project_id == Project.id)
        .outerjoin(PrintArchive, LibraryFolder.archive_id == PrintArchive.id)
        .where(LibraryFolder.id == folder_id)
    )
    row = result.one_or_none()

    if not row:
        raise HTTPException(status_code=404, detail="Folder not found")

    folder, project_name, archive_name = row

    # Get file count
    file_count_result = await db.execute(
        select(func.count(LibraryFile.id)).where(
            LibraryFile.folder_id == folder_id,
            LibraryFile.deleted_at.is_(None),
        )
    )
    file_count = file_count_result.scalar() or 0

    return FolderResponse(
        id=folder.id,
        name=folder.name,
        parent_id=folder.parent_id,
        project_id=folder.project_id,
        archive_id=folder.archive_id,
        project_name=project_name,
        archive_name=archive_name,
        is_external=folder.is_external,
        external_path=folder.external_path,
        external_readonly=folder.external_readonly,
        external_show_hidden=folder.external_show_hidden,
        file_count=file_count,
        created_at=folder.created_at,
        updated_at=folder.updated_at,
    )


@router.put("/folders/{folder_id}", response_model=FolderResponse)
async def update_folder(
    folder_id: int,
    data: FolderUpdate,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPDATE_ALL)),
):
    """Update a folder.

    Note: Folders require library:update_all permission since they don't have
    ownership tracking.
    """
    result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == folder_id))
    folder = result.scalar_one_or_none()

    if not folder:
        raise HTTPException(status_code=404, detail="Folder not found")

    if data.name is not None:
        folder.name = data.name

    if data.parent_id is not None:
        # Prevent circular reference
        if data.parent_id == folder_id:
            raise HTTPException(status_code=400, detail="Folder cannot be its own parent")

        # Check for circular reference in ancestors
        if data.parent_id != 0:  # 0 means move to root
            current_id = data.parent_id
            while current_id is not None:
                if current_id == folder_id:
                    raise HTTPException(status_code=400, detail="Cannot move folder into its own subtree")
                parent_result = await db.execute(select(LibraryFolder.parent_id).where(LibraryFolder.id == current_id))
                current_id = parent_result.scalar()

            folder.parent_id = data.parent_id
        else:
            folder.parent_id = None

    # Update project_id (0 to unlink)
    if data.project_id is not None:
        if data.project_id == 0:
            folder.project_id = None
        else:
            # Verify project exists
            project_result = await db.execute(select(Project).where(Project.id == data.project_id))
            if not project_result.scalar_one_or_none():
                raise HTTPException(status_code=404, detail="Project not found")
            folder.project_id = data.project_id

    # Update archive_id (0 to unlink)
    if data.archive_id is not None:
        if data.archive_id == 0:
            folder.archive_id = None
        else:
            # Verify archive exists
            archive_result = await db.execute(select(PrintArchive).where(PrintArchive.id == data.archive_id))
            if not archive_result.scalar_one_or_none():
                raise HTTPException(status_code=404, detail="Archive not found")
            folder.archive_id = data.archive_id

    await db.commit()
    await db.refresh(folder)

    # Get file count and names
    file_count_result = await db.execute(
        select(func.count(LibraryFile.id)).where(
            LibraryFile.folder_id == folder_id,
            LibraryFile.deleted_at.is_(None),
        )
    )
    file_count = file_count_result.scalar() or 0

    # Get project and archive names
    project_name = None
    archive_name = None
    if folder.project_id:
        project_result = await db.execute(select(Project.name).where(Project.id == folder.project_id))
        project_name = project_result.scalar()
    if folder.archive_id:
        archive_result = await db.execute(select(PrintArchive.print_name).where(PrintArchive.id == folder.archive_id))
        archive_name = archive_result.scalar()

    return FolderResponse(
        id=folder.id,
        name=folder.name,
        parent_id=folder.parent_id,
        project_id=folder.project_id,
        archive_id=folder.archive_id,
        project_name=project_name,
        archive_name=archive_name,
        is_external=folder.is_external,
        external_path=folder.external_path,
        external_readonly=folder.external_readonly,
        external_show_hidden=folder.external_show_hidden,
        file_count=file_count,
        created_at=folder.created_at,
        updated_at=folder.updated_at,
    )


@router.delete("/folders/{folder_id}")
async def delete_folder(
    folder_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_DELETE_ALL)),
):
    """Delete a folder and all its contents (cascade).

    Note: Folders require library:delete_all permission since they don't have
    ownership tracking.
    """
    result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == folder_id))
    folder = result.scalar_one_or_none()

    if not folder:
        raise HTTPException(status_code=404, detail="Folder not found")

    # External folders: only remove DB records, never delete files from external path
    is_ext = folder.is_external

    # Get all files in this folder and subfolders to delete from disk
    async def get_all_file_ids(fid: int) -> list[int]:
        """Recursively get all file IDs in a folder tree."""
        file_ids = []

        # Get files in this folder
        files_result = await db.execute(
            select(LibraryFile.id, LibraryFile.file_path, LibraryFile.thumbnail_path, LibraryFile.is_external).where(
                LibraryFile.folder_id == fid
            )
        )
        for fid_val, file_path, thumb_path, file_is_ext in files_result.all():
            file_ids.append(fid_val)
            # Only delete non-external files from disk
            if not is_ext and not file_is_ext:
                try:
                    if file_path and os.path.exists(file_path):
                        os.remove(file_path)
                    if thumb_path and os.path.exists(thumb_path):
                        os.remove(thumb_path)
                except OSError as e:
                    logger.warning("Failed to delete file: %s", e)

        # Get child folders and recurse
        children_result = await db.execute(select(LibraryFolder.id).where(LibraryFolder.parent_id == fid))
        for (child_id,) in children_result.all():
            file_ids.extend(await get_all_file_ids(child_id))

        return file_ids

    await get_all_file_ids(folder_id)

    # Delete folder (cascade will handle files and subfolders)
    await db.delete(folder)
    await db.commit()

    return {"status": "success", "message": "Folder deleted"}


# ============ External Folder Endpoints ============

# Blocked system directories that cannot be mounted
_BLOCKED_PREFIXES = (
    "/proc",
    "/sys",
    "/dev",
    "/run",
    "/boot",
    "/sbin",
    "/bin",
    "/usr/sbin",
    "/usr/bin",
    "/lib",
    "/etc",
)

# Supported file extensions for external folder scanning
_SCANNABLE_EXTENSIONS = {
    ".3mf",
    ".gcode",
    ".gcode.3mf",
    ".stl",
    ".obj",
    ".step",
    ".stp",
    ".png",
    ".jpg",
    ".jpeg",
    ".gif",
    ".webp",
    ".svg",
}


def _validate_external_path(path_str: str) -> Path:
    """Validate an external path is safe to mount."""
    path = Path(path_str).resolve()

    if not path.is_absolute():
        raise HTTPException(status_code=400, detail="Path must be absolute")

    for prefix in _BLOCKED_PREFIXES:
        if str(path).startswith(prefix):
            raise HTTPException(status_code=400, detail=f"Cannot mount system directory: {prefix}")

    if not path.exists():
        raise HTTPException(status_code=400, detail=f"Path does not exist: {path}")

    if not path.is_dir():
        raise HTTPException(status_code=400, detail=f"Path is not a directory: {path}")

    # Check readability
    if not os.access(path, os.R_OK):
        raise HTTPException(status_code=400, detail=f"Path is not readable: {path}")

    return path


@router.post("/folders/external", response_model=FolderResponse)
async def create_external_folder(
    data: ExternalFolderCreate,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPLOAD)),
):
    """Create an external folder that points to a host directory."""
    resolved = _validate_external_path(data.external_path)

    # Check no other external folder already points to this path
    existing = await db.execute(
        select(LibraryFolder).where(
            LibraryFolder.is_external.is_(True),
            LibraryFolder.external_path == str(resolved),
        )
    )
    if existing.scalar_one_or_none():
        raise HTTPException(status_code=409, detail="An external folder already exists for this path")

    # Verify parent exists if specified
    if data.parent_id is not None:
        parent_result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == data.parent_id))
        if not parent_result.scalar_one_or_none():
            raise HTTPException(status_code=404, detail="Parent folder not found")

    folder = LibraryFolder(
        name=data.name,
        parent_id=data.parent_id,
        is_external=True,
        external_path=str(resolved),
        external_readonly=data.readonly,
        external_show_hidden=data.show_hidden,
    )
    db.add(folder)
    await db.commit()
    await db.refresh(folder)

    return FolderResponse(
        id=folder.id,
        name=folder.name,
        parent_id=folder.parent_id,
        project_id=None,
        archive_id=None,
        is_external=True,
        external_path=folder.external_path,
        external_readonly=folder.external_readonly,
        external_show_hidden=folder.external_show_hidden,
        file_count=0,
        created_at=folder.created_at,
        updated_at=folder.updated_at,
    )


@router.post("/folders/{folder_id}/scan")
async def scan_external_folder(
    folder_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPLOAD)),
):
    """Scan an external folder and sync files to the database.

    Discovers new files, removes DB entries for deleted files.
    Does not copy files — stores the external path directly.
    """
    result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == folder_id))
    folder = result.scalar_one_or_none()

    if not folder:
        raise HTTPException(status_code=404, detail="Folder not found")
    if not folder.is_external or not folder.external_path:
        raise HTTPException(status_code=400, detail="Not an external folder")

    ext_path = Path(folder.external_path)
    if not ext_path.exists() or not ext_path.is_dir():
        raise HTTPException(status_code=400, detail=f"External path is not accessible: {folder.external_path}")

    # Collect all existing child external subfolder IDs (single query)
    all_folder_ids = [folder_id]
    child_result = await db.execute(
        select(LibraryFolder).where(
            LibraryFolder.is_external.is_(True),
            LibraryFolder.parent_id.isnot(None),
        )
    )
    all_child_folders = child_result.scalars().all()

    # Walk the parent chain to find all descendants of folder_id
    parent_to_children: dict[int, list] = {}
    for cf in all_child_folders:
        parent_to_children.setdefault(cf.parent_id, []).append(cf)

    queue = [folder_id]
    while queue:
        pid = queue.pop()
        for child in parent_to_children.get(pid, []):
            all_folder_ids.append(child.id)
            queue.append(child.id)

    # Get existing DB files across root and all subfolders
    existing_result = await db.execute(
        LibraryFile.active().where(
            LibraryFile.folder_id.in_(all_folder_ids),
            LibraryFile.is_external.is_(True),
        )
    )
    existing_files = {f.file_path: f for f in existing_result.scalars().all()}

    # Build folder cache: relative path -> folder_id (for resolving subfolders)
    # Pre-populate with existing child folders keyed by their external_path
    folder_cache: dict[str, int] = {"": folder_id}
    for fid in all_folder_ids:
        if fid == folder_id:
            continue
        # Find the child folder object
        for cf in all_child_folders:
            if cf.id == fid and cf.external_path:
                try:
                    rel = str(Path(cf.external_path).relative_to(ext_path))
                    if rel != ".":
                        folder_cache[rel] = cf.id
                except ValueError:
                    pass

    # Scan the directory
    added = 0
    removed = 0
    found_paths: set[str] = set()
    seen_rel_dirs: set[str] = set()

    for dirpath, dirnames, filenames in os.walk(ext_path):
        # Filter hidden directories unless configured
        if not folder.external_show_hidden:
            dirnames[:] = [d for d in dirnames if not d.startswith(".")]

        rel_dir = str(Path(dirpath).relative_to(ext_path))
        if rel_dir == ".":
            rel_dir = ""
        seen_rel_dirs.add(rel_dir)

        # Resolve or create subfolder chain for this directory
        if rel_dir and rel_dir not in folder_cache:
            parts = Path(rel_dir).parts
            current_path = ""
            current_parent = folder_id
            for part in parts:
                current_path = f"{current_path}/{part}".lstrip("/")
                if current_path in folder_cache:
                    current_parent = folder_cache[current_path]
                else:
                    existing_sub = await db.execute(
                        select(LibraryFolder).where(
                            LibraryFolder.name == part,
                            LibraryFolder.parent_id == current_parent,
                            LibraryFolder.is_external.is_(True),
                        )
                    )
                    existing_folder = existing_sub.scalar_one_or_none()
                    if existing_folder:
                        current_parent = existing_folder.id
                    else:
                        new_folder = LibraryFolder(
                            name=part,
                            parent_id=current_parent,
                            is_external=True,
                            external_path=str(ext_path / current_path),
                            external_readonly=folder.external_readonly,
                            external_show_hidden=folder.external_show_hidden,
                        )
                        db.add(new_folder)
                        await db.flush()
                        current_parent = new_folder.id
                    folder_cache[current_path] = current_parent

        target_folder_id = folder_cache.get(rel_dir, folder_id)

        for filename in filenames:
            # Skip hidden files unless configured
            if not folder.external_show_hidden and filename.startswith("."):
                continue

            filepath = Path(dirpath) / filename
            ext = filepath.suffix.lower()

            # Check for compound extensions like .gcode.3mf
            if ext not in _SCANNABLE_EXTENSIONS:
                # Check compound
                compound = "".join(filepath.suffixes[-2:]).lower() if len(filepath.suffixes) >= 2 else ""
                if compound not in _SCANNABLE_EXTENSIONS:
                    continue

            # Resolve symlinks and ensure still under external_path
            try:
                real_path = filepath.resolve()
                real_path.relative_to(ext_path.resolve())
            except (ValueError, OSError):
                continue  # Symlink escapes the external dir

            file_path_str = str(filepath)
            found_paths.add(file_path_str)

            if file_path_str in existing_files:
                continue  # Already tracked

            # Get file info
            try:
                stat = filepath.stat()
            except OSError:
                continue

            file_type = ext[1:] if ext else "unknown"
            # For compound extensions, use the meaningful part
            if file_type in ("3mf",) and len(filepath.suffixes) >= 2:
                inner = filepath.suffixes[-2].lower()
                if inner == ".gcode":
                    file_type = "gcode.3mf"

            # Extract thumbnail for 3mf files
            thumbnail_path = None
            file_metadata = None
            if file_type == "3mf":
                try:
                    parser = ThreeMFParser(str(filepath))
                    raw_metadata = parser.parse()
                    if raw_metadata:
                        # Extract thumbnail before cleaning metadata
                        thumb_data = raw_metadata.get("_thumbnail_data")
                        thumbnail_ext = raw_metadata.get("_thumbnail_ext", ".png")
                        if thumb_data:
                            thumb_dir = get_library_thumbnails_dir()
                            thumb_filename = f"{uuid.uuid4().hex}{thumbnail_ext}"
                            thumb_full = thumb_dir / thumb_filename
                            thumb_full.write_bytes(thumb_data)
                            thumbnail_path = to_relative_path(thumb_full)

                        # Clean metadata - remove non-JSON-serializable data (bytes, etc.)
                        def clean_metadata(obj):
                            if isinstance(obj, dict):
                                return {
                                    k: clean_metadata(v)
                                    for k, v in obj.items()
                                    if not isinstance(v, bytes) and k not in ("_thumbnail_data", "_thumbnail_ext")
                                }
                            elif isinstance(obj, list):
                                return [clean_metadata(i) for i in obj if not isinstance(i, bytes)]
                            elif isinstance(obj, bytes):
                                return None
                            return obj

                        file_metadata = clean_metadata(raw_metadata)
                except Exception as e:
                    logger.debug("Failed to extract metadata from external 3mf %s: %s", filepath, e)

            # Generate thumbnail for STL files
            if file_type == "stl" and thumbnail_path is None:
                try:
                    thumb_dir = get_library_thumbnails_dir()
                    thumb_result = generate_stl_thumbnail(str(filepath), str(thumb_dir))
                    if thumb_result:
                        thumbnail_path = to_relative_path(Path(thumb_result))
                except Exception as e:
                    logger.debug("Failed to generate STL thumbnail for external %s: %s", filepath, e)

            # Extract gcode thumbnail
            if file_type == "gcode" and thumbnail_path is None:
                thumb_data = extract_gcode_thumbnail(filepath)
                if thumb_data:
                    thumb_dir = get_library_thumbnails_dir()
                    thumb_filename = f"{uuid.uuid4().hex}.png"
                    thumb_full = thumb_dir / thumb_filename
                    thumb_full.write_bytes(thumb_data)
                    thumbnail_path = to_relative_path(thumb_full)

            # Create thumbnail for image files
            if ext.lower() in IMAGE_EXTENSIONS and thumbnail_path is None:
                thumbnail_path_str = create_image_thumbnail(filepath, get_library_thumbnails_dir())
                if thumbnail_path_str:
                    thumbnail_path = to_relative_path(Path(thumbnail_path_str))

            db_file = LibraryFile(
                folder_id=target_folder_id,
                is_external=True,
                filename=filename,
                file_path=file_path_str,
                file_type=file_type,
                file_size=stat.st_size,
                file_hash=None,  # Skip hashing external files for performance
                thumbnail_path=thumbnail_path,
                file_metadata=file_metadata,
            )
            db.add(db_file)
            added += 1

    # Remove DB entries for files that no longer exist on disk
    for path_str, db_file in existing_files.items():
        if path_str not in found_paths:
            # Clean up thumbnail if we generated one
            if db_file.thumbnail_path:
                try:
                    abs_thumb = to_absolute_path(db_file.thumbnail_path)
                    if abs_thumb and abs_thumb.exists():
                        abs_thumb.unlink()
                except OSError:
                    pass
            await db.delete(db_file)
            removed += 1

    # Remove empty subfolders whose directories no longer exist on disk
    # Process deepest-first by sorting on path depth (descending)
    subfolder_entries = [(rel, fid) for rel, fid in folder_cache.items() if rel and fid != folder_id]
    subfolder_entries.sort(key=lambda x: x[0].count("/"), reverse=True)
    for rel_path, sub_fid in subfolder_entries:
        if rel_path in seen_rel_dirs:
            continue  # Directory still exists on disk
        # Check if subfolder has any remaining files
        file_count_result = await db.execute(
            select(func.count(LibraryFile.id)).where(
                LibraryFile.folder_id == sub_fid,
                LibraryFile.deleted_at.is_(None),
            )
        )
        if (file_count_result.scalar() or 0) == 0:
            # Check if it has any remaining child folders
            child_count_result = await db.execute(
                select(func.count(LibraryFolder.id)).where(LibraryFolder.parent_id == sub_fid)
            )
            if (child_count_result.scalar() or 0) == 0:
                sub_folder_result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == sub_fid))
                sub_folder_obj = sub_folder_result.scalar_one_or_none()
                if sub_folder_obj:
                    await db.delete(sub_folder_obj)

    await db.commit()

    return {"status": "success", "added": added, "removed": removed}


# ============ File Endpoints ============


@router.get("/files", response_model=list[FileListResponse])
@router.get("/files/", response_model=list[FileListResponse])
async def list_files(
    response: Response,
    folder_id: int | None = None,
    project_id: int | None = None,
    include_root: bool = True,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """List files, optionally filtered by folder or project.

    Args:
        folder_id: Filter by folder ID. If None and include_root=True, returns root files.
        project_id: Return all files across folders linked to this project (bulk fetch, avoids N+1).
        include_root: If True and folder_id is None, returns files at root level.
                     If False and folder_id is None, returns all files.
    """
    query = LibraryFile.active().options(selectinload(LibraryFile.created_by))

    if folder_id is not None:
        query = query.where(LibraryFile.folder_id == folder_id)
    elif project_id is not None:
        # Single join instead of one query per folder (avoids N+1 pattern)
        query = query.join(LibraryFolder, LibraryFile.folder_id == LibraryFolder.id)
        query = query.where(LibraryFolder.project_id == project_id)
    elif include_root:
        query = query.where(LibraryFile.folder_id.is_(None))

    query = query.order_by(LibraryFile.filename)
    result = await db.execute(query)
    files = result.scalars().all()

    # Get duplicate counts
    hash_counts = {}
    if files:
        hashes = [f.file_hash for f in files if f.file_hash]
        if hashes:
            dup_result = await db.execute(
                select(LibraryFile.file_hash, func.count(LibraryFile.id))
                .where(LibraryFile.file_hash.in_(hashes), LibraryFile.deleted_at.is_(None))
                .group_by(LibraryFile.file_hash)
            )
            hash_counts = {h: c - 1 for h, c in dup_result.all()}  # -1 to exclude self

    # Prevent browser caching of file list
    response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"

    file_list = []
    for f in files:
        # Extract key metadata for display
        print_name = None
        print_time = None
        filament_grams = None
        sliced_for_model = None
        if f.file_metadata:
            print_name = f.file_metadata.get("print_name")
            print_time = f.file_metadata.get("print_time_seconds")
            filament_grams = f.file_metadata.get("filament_used_grams")
            sliced_for_model = f.file_metadata.get("sliced_for_model")

        file_list.append(
            FileListResponse(
                id=f.id,
                folder_id=f.folder_id,
                is_external=f.is_external,
                filename=f.filename,
                file_type=f.file_type,
                file_size=f.file_size,
                thumbnail_path=f.thumbnail_path,
                print_count=f.print_count,
                duplicate_count=hash_counts.get(f.file_hash, 0) if f.file_hash else 0,
                created_by_id=f.created_by_id,
                created_by_username=f.created_by.username if f.created_by else None,
                created_at=f.created_at,
                print_name=print_name,
                print_time_seconds=print_time,
                filament_used_grams=filament_grams,
                sliced_for_model=sliced_for_model,
            )
        )

    return file_list


@router.post("/files", response_model=FileUploadResponse)
@router.post("/files/", response_model=FileUploadResponse)
async def upload_file(
    file: UploadFile = File(...),
    folder_id: int | None = None,
    generate_stl_thumbnails: bool = Query(default=True),
    db: AsyncSession = Depends(get_db),
    current_user: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPLOAD)),
):
    """Upload a file to the library."""
    try:
        if not file.filename:
            raise HTTPException(status_code=400, detail="Filename is required")

        filename = file.filename
        ext = os.path.splitext(filename)[1].lower()
        # Handle files without extension
        file_type = ext[1:] if ext else "unknown"

        # Verify folder exists if specified
        target_folder = None
        if folder_id is not None:
            folder_result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == folder_id))
            target_folder = folder_result.scalar_one_or_none()
            if not target_folder:
                raise HTTPException(status_code=404, detail="Folder not found")

        # Writable external folders write through to the mount so the file is
        # visible outside Bambuddy (#1112); everything else lands under the
        # internal library dir with a UUID-scoped filename.
        file_path, is_external_upload = _resolve_upload_destination(target_folder, filename)

        # Save file
        content = await file.read()
        with open(file_path, "wb") as f:
            f.write(content)

        # Calculate hash
        file_hash = calculate_file_hash(file_path)

        # Check for duplicates
        dup_result = await db.execute(
            select(LibraryFile.id).where(LibraryFile.file_hash == file_hash, LibraryFile.deleted_at.is_(None)).limit(1)
        )
        duplicate_of = dup_result.scalar()

        # Extract metadata and thumbnail
        metadata = {}
        thumbnail_path = None
        thumbnails_dir = get_library_thumbnails_dir()

        if ext == ".3mf":
            try:
                parser = ThreeMFParser(str(file_path))
                raw_metadata = parser.parse()

                # Extract thumbnail before cleaning metadata
                thumbnail_data = raw_metadata.get("_thumbnail_data")
                thumbnail_ext = raw_metadata.get("_thumbnail_ext", ".png")

                # Save thumbnail if extracted
                if thumbnail_data:
                    thumb_filename = f"{uuid.uuid4().hex}{thumbnail_ext}"
                    thumb_path = thumbnails_dir / thumb_filename
                    with open(thumb_path, "wb") as f:
                        f.write(thumbnail_data)
                    thumbnail_path = str(thumb_path)

                # Clean metadata - remove non-JSON-serializable data (bytes, etc.)
                def clean_metadata(obj):
                    if isinstance(obj, dict):
                        return {
                            k: clean_metadata(v)
                            for k, v in obj.items()
                            if not isinstance(v, bytes) and k not in ("_thumbnail_data", "_thumbnail_ext")
                        }
                    elif isinstance(obj, list):
                        return [clean_metadata(i) for i in obj if not isinstance(i, bytes)]
                    elif isinstance(obj, bytes):
                        return None
                    return obj

                metadata = clean_metadata(raw_metadata)
            except Exception as e:
                logger.warning("Failed to parse 3MF: %s", e)

        elif ext == ".gcode":
            # Extract embedded thumbnail from gcode
            try:
                thumbnail_data = extract_gcode_thumbnail(file_path)
                if thumbnail_data:
                    thumb_filename = f"{uuid.uuid4().hex}.png"
                    thumb_path = thumbnails_dir / thumb_filename
                    with open(thumb_path, "wb") as f:
                        f.write(thumbnail_data)
                    thumbnail_path = str(thumb_path)
            except Exception as e:
                logger.warning("Failed to extract gcode thumbnail: %s", e)

        elif ext.lower() in IMAGE_EXTENSIONS:
            # For image files, create a thumbnail from the image itself
            thumbnail_path = create_image_thumbnail(file_path, thumbnails_dir)

        elif ext == ".stl":
            # Generate STL thumbnail if enabled
            if generate_stl_thumbnails:
                thumbnail_path = generate_stl_thumbnail(file_path, thumbnails_dir)

        # Create database entry (managed files store relative paths for portability;
        # external files store the absolute mount path — same shape as scan produces)
        library_file = LibraryFile(
            folder_id=folder_id,
            is_external=is_external_upload,
            filename=filename,
            file_path=_stored_file_path(file_path, is_external_upload),
            file_type=file_type,
            file_size=len(content),
            file_hash=file_hash,
            thumbnail_path=to_relative_path(thumbnail_path) if thumbnail_path else None,
            file_metadata=metadata if metadata else None,
            created_by_id=current_user.id if current_user else None,
        )
        db.add(library_file)
        await db.commit()
        await db.refresh(library_file)

        return FileUploadResponse(
            id=library_file.id,
            filename=library_file.filename,
            file_type=library_file.file_type,
            file_size=library_file.file_size,
            thumbnail_path=library_file.thumbnail_path,
            duplicate_of=duplicate_of,
            metadata=library_file.file_metadata,
        )
    except HTTPException:
        raise
    except Exception as e:
        logger.error("Upload failed for %s: %s", file.filename, e, exc_info=True)
        raise HTTPException(status_code=500, detail=f"Upload failed: {str(e)}")


@router.post("/files/extract-zip", response_model=ZipExtractResponse)
async def extract_zip_file(
    file: UploadFile = File(...),
    folder_id: int | None = Query(default=None),
    preserve_structure: bool = Query(default=True),
    create_folder_from_zip: bool = Query(default=False),
    generate_stl_thumbnails: bool = Query(default=True),
    db: AsyncSession = Depends(get_db),
    current_user: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPLOAD)),
):
    """Upload and extract a ZIP file to the library.

    Args:
        file: The ZIP file to extract
        folder_id: Target folder ID (None = root)
        preserve_structure: If True, recreate folder structure from ZIP; if False, extract all files flat
        create_folder_from_zip: If True, create a folder named after the ZIP file and extract into it
        generate_stl_thumbnails: If True, generate thumbnails for STL files
    """
    import tempfile

    if not file.filename or not file.filename.lower().endswith(".zip"):
        raise HTTPException(status_code=400, detail="Only ZIP files are supported")

    # Verify target folder exists if specified
    if folder_id is not None:
        folder_result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == folder_id))
        target_folder = folder_result.scalar_one_or_none()
        if not target_folder:
            raise HTTPException(status_code=404, detail="Target folder not found")
        if target_folder.is_external and target_folder.external_readonly:
            raise HTTPException(status_code=403, detail="Cannot extract ZIP to a read-only external folder")
        if target_folder.is_external:
            # Writable external folders aren't supported by extract-zip because the
            # nested-subfolder creation path would need to mkdir on the mount and
            # create matching is_external=True LibraryFolder rows — a separate
            # design. Direct the user at Scan, which already handles that shape
            # (#1112).
            raise HTTPException(
                status_code=400,
                detail=(
                    "Cannot extract ZIP directly into an external folder. "
                    "Extract the ZIP on the external mount and run 'Scan External Folder' instead."
                ),
            )

    # Save ZIP to temp file
    try:
        with tempfile.NamedTemporaryFile(delete=False, suffix=".zip") as tmp:
            content = await file.read()
            tmp.write(content)
            tmp_path = tmp.name
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Failed to save ZIP file: {str(e)}")

    extracted_files: list[ZipExtractResult] = []
    errors: list[ZipExtractError] = []
    folders_created = 0
    folder_cache: dict[str, int] = {}  # path -> folder_id

    # If create_folder_from_zip is True, create a folder named after the ZIP file
    zip_folder_id = folder_id
    logger.info(
        f"ZIP extraction: create_folder_from_zip={create_folder_from_zip}, folder_id={folder_id}, filename={file.filename}"
    )
    if create_folder_from_zip and file.filename:
        # Remove .zip extension to get folder name
        zip_folder_name = file.filename[:-4] if file.filename.lower().endswith(".zip") else file.filename
        # Check if folder already exists
        existing = await db.execute(
            select(LibraryFolder).where(
                LibraryFolder.name == zip_folder_name,
                LibraryFolder.parent_id == folder_id if folder_id else LibraryFolder.parent_id.is_(None),
            )
        )
        existing_folder = existing.scalar_one_or_none()
        if existing_folder:
            zip_folder_id = existing_folder.id
            logger.info("Reusing existing folder '%s' with id=%s", zip_folder_name, zip_folder_id)
        else:
            # Create folder
            new_folder = LibraryFolder(name=zip_folder_name, parent_id=folder_id)
            db.add(new_folder)
            await db.flush()
            await db.commit()  # Commit folder creation immediately
            zip_folder_id = new_folder.id
            folders_created += 1
            logger.info("Created new folder '%s' with id=%s", zip_folder_name, zip_folder_id)

    try:
        with zipfile.ZipFile(tmp_path, "r") as zf:
            # Filter out directories and hidden/system files
            file_list = [
                name
                for name in zf.namelist()
                if not name.endswith("/")
                and not name.startswith("__MACOSX")
                and not os.path.basename(name).startswith(".")
            ]

            for zip_path in file_list:
                try:
                    # Determine target folder (use zip_folder_id as base if create_folder_from_zip was used)
                    target_folder_id = zip_folder_id

                    if preserve_structure:
                        # Get directory path from ZIP
                        dir_path = os.path.dirname(zip_path)
                        if dir_path:
                            # Create folder structure
                            parts = dir_path.split("/")
                            current_parent = zip_folder_id
                            current_path = ""

                            for part in parts:
                                if not part:
                                    continue
                                current_path = f"{current_path}/{part}" if current_path else part

                                if current_path in folder_cache:
                                    current_parent = folder_cache[current_path]
                                else:
                                    # Check if folder exists
                                    existing = await db.execute(
                                        select(LibraryFolder).where(
                                            LibraryFolder.name == part,
                                            LibraryFolder.parent_id == current_parent
                                            if current_parent
                                            else LibraryFolder.parent_id.is_(None),
                                        )
                                    )
                                    existing_folder = existing.scalar_one_or_none()

                                    if existing_folder:
                                        current_parent = existing_folder.id
                                    else:
                                        # Create folder
                                        new_folder = LibraryFolder(name=part, parent_id=current_parent)
                                        db.add(new_folder)
                                        await db.flush()
                                        current_parent = new_folder.id
                                        folders_created += 1

                                    folder_cache[current_path] = current_parent

                            target_folder_id = current_parent

                    # Extract file
                    filename = os.path.basename(zip_path)
                    ext = os.path.splitext(filename)[1].lower()
                    file_type = ext[1:] if ext else "unknown"

                    # Generate unique filename for storage
                    unique_filename = f"{uuid.uuid4().hex}{ext}"
                    file_path = get_library_files_dir() / unique_filename

                    # Extract and save file
                    file_content = zf.read(zip_path)
                    with open(file_path, "wb") as f:
                        f.write(file_content)

                    # Calculate hash
                    file_hash = calculate_file_hash(file_path)

                    # Extract metadata and thumbnail for 3MF files
                    metadata = {}
                    thumbnail_path = None
                    thumbnails_dir = get_library_thumbnails_dir()

                    if ext == ".3mf":
                        try:
                            parser = ThreeMFParser(str(file_path))
                            raw_metadata = parser.parse()

                            thumbnail_data = raw_metadata.get("_thumbnail_data")
                            thumbnail_ext = raw_metadata.get("_thumbnail_ext", ".png")

                            if thumbnail_data:
                                thumb_filename = f"{uuid.uuid4().hex}{thumbnail_ext}"
                                thumb_path = thumbnails_dir / thumb_filename
                                with open(thumb_path, "wb") as f:
                                    f.write(thumbnail_data)
                                thumbnail_path = str(thumb_path)

                            def clean_metadata(obj):
                                if isinstance(obj, dict):
                                    return {
                                        k: clean_metadata(v)
                                        for k, v in obj.items()
                                        if not isinstance(v, bytes) and k not in ("_thumbnail_data", "_thumbnail_ext")
                                    }
                                elif isinstance(obj, list):
                                    return [clean_metadata(i) for i in obj if not isinstance(i, bytes)]
                                elif isinstance(obj, bytes):
                                    return None
                                return obj

                            metadata = clean_metadata(raw_metadata)
                        except Exception as e:
                            logger.warning("Failed to parse 3MF from ZIP: %s", e)

                    elif ext == ".gcode":
                        try:
                            thumbnail_data = extract_gcode_thumbnail(file_path)
                            if thumbnail_data:
                                thumb_filename = f"{uuid.uuid4().hex}.png"
                                thumb_path = thumbnails_dir / thumb_filename
                                with open(thumb_path, "wb") as f:
                                    f.write(thumbnail_data)
                                thumbnail_path = str(thumb_path)
                        except Exception as e:
                            logger.warning("Failed to extract gcode thumbnail from ZIP: %s", e)

                    elif ext.lower() in IMAGE_EXTENSIONS:
                        thumbnail_path = create_image_thumbnail(file_path, thumbnails_dir)

                    elif ext == ".stl":
                        # Generate STL thumbnail if enabled
                        if generate_stl_thumbnails:
                            thumbnail_path = generate_stl_thumbnail(file_path, thumbnails_dir)

                    # Create database entry (store relative paths for portability)
                    library_file = LibraryFile(
                        folder_id=target_folder_id,
                        filename=filename,
                        file_path=to_relative_path(file_path),
                        file_type=file_type,
                        file_size=len(file_content),
                        file_hash=file_hash,
                        thumbnail_path=to_relative_path(thumbnail_path) if thumbnail_path else None,
                        file_metadata=metadata if metadata else None,
                        created_by_id=current_user.id if current_user else None,
                    )
                    db.add(library_file)
                    await db.flush()
                    await db.refresh(library_file)

                    extracted_files.append(
                        ZipExtractResult(
                            filename=filename,
                            file_id=library_file.id,
                            folder_id=target_folder_id,
                        )
                    )

                    # Commit after each file to release database lock
                    # This prevents long-running transactions from blocking other requests
                    await db.commit()

                except Exception as e:
                    logger.error("Failed to extract %s: %s", zip_path, e)
                    errors.append(ZipExtractError(filename=os.path.basename(zip_path), error=str(e)))
                    # Rollback the failed file but continue with others
                    await db.rollback()

        return ZipExtractResponse(
            extracted=len(extracted_files),
            folders_created=folders_created,
            files=extracted_files,
            errors=errors,
        )

    except zipfile.BadZipFile:
        raise HTTPException(status_code=400, detail="Invalid or corrupted ZIP file")
    except Exception as e:
        logger.error("ZIP extraction failed: %s", e, exc_info=True)
        raise HTTPException(status_code=500, detail=f"ZIP extraction failed: {str(e)}")
    finally:
        # Clean up temp file
        try:
            os.unlink(tmp_path)
        except OSError:
            pass  # Best-effort temp file cleanup; ignore if already removed


# ============ STL Thumbnail Batch Generation ============


@router.post("/generate-stl-thumbnails", response_model=BatchThumbnailResponse)
async def batch_generate_stl_thumbnails(
    request: BatchThumbnailRequest,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPDATE_ALL)),
):
    """Generate thumbnails for STL files in batch.

    Note: Requires library:update_all permission since this is a batch operation
    that may affect files owned by different users.

    Can generate thumbnails for:
    - Specific file IDs (file_ids)
    - All STL files in a folder (folder_id)
    - All STL files missing thumbnails (all_missing=True)
    """
    thumbnails_dir = get_library_thumbnails_dir()
    results: list[BatchThumbnailResult] = []

    # Build query based on request
    query = LibraryFile.active().where(LibraryFile.file_type == "stl")

    if request.file_ids:
        # Specific files
        query = query.where(LibraryFile.id.in_(request.file_ids))
    elif request.folder_id is not None:
        # All STL files in a specific folder
        query = query.where(LibraryFile.folder_id == request.folder_id)
        if not request.all_missing:
            # If not specifically asking for missing thumbnails, get all
            pass
        else:
            query = query.where(LibraryFile.thumbnail_path.is_(None))
    elif request.all_missing:
        # All STL files without thumbnails
        query = query.where(LibraryFile.thumbnail_path.is_(None))
    else:
        # No criteria specified - return empty
        return BatchThumbnailResponse(
            processed=0,
            succeeded=0,
            failed=0,
            results=[],
        )

    result = await db.execute(query)
    stl_files = result.scalars().all()

    succeeded = 0
    failed = 0

    for stl_file in stl_files:
        file_path = to_absolute_path(stl_file.file_path)

        if not file_path or not file_path.exists():
            results.append(
                BatchThumbnailResult(
                    file_id=stl_file.id,
                    filename=stl_file.filename,
                    success=False,
                    error="File not found on disk",
                )
            )
            failed += 1
            continue

        try:
            thumbnail_path = generate_stl_thumbnail(file_path, thumbnails_dir)

            if thumbnail_path:
                # Update database with relative path
                stl_file.thumbnail_path = to_relative_path(thumbnail_path)
                await db.flush()
                results.append(
                    BatchThumbnailResult(
                        file_id=stl_file.id,
                        filename=stl_file.filename,
                        success=True,
                    )
                )
                succeeded += 1
            else:
                results.append(
                    BatchThumbnailResult(
                        file_id=stl_file.id,
                        filename=stl_file.filename,
                        success=False,
                        error="Thumbnail generation failed",
                    )
                )
                failed += 1
        except Exception as e:
            logger.error("Failed to generate thumbnail for %s: %s", stl_file.filename, e)
            results.append(
                BatchThumbnailResult(
                    file_id=stl_file.id,
                    filename=stl_file.filename,
                    success=False,
                    error=str(e),
                )
            )
            failed += 1

    await db.commit()

    return BatchThumbnailResponse(
        processed=len(stl_files),
        succeeded=succeeded,
        failed=failed,
        results=results,
    )


# ============ Queue Operations ============
# NOTE: These routes must be defined BEFORE /files/{file_id} to avoid path parameter conflicts


def is_sliced_file(filename: str) -> bool:
    """Check if a file is a sliced (printable) file.

    Sliced files are:
    - .gcode files
    - .3mf files that contain '.gcode.' in the name (e.g., filename.gcode.3mf)
    """
    lower = filename.lower()
    return lower.endswith(".gcode") or ".gcode." in lower


@router.post("/files/add-to-queue", response_model=AddToQueueResponse)
async def add_files_to_queue(
    request: AddToQueueRequest,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.QUEUE_CREATE)),
):
    """Add library files to the print queue.

    Only sliced files (.gcode or .gcode.3mf) can be added to the queue.
    The archive will be created automatically when the print starts.
    """
    added: list[AddToQueueResult] = []
    errors: list[AddToQueueError] = []

    # Get all requested files
    result = await db.execute(LibraryFile.active().where(LibraryFile.id.in_(request.file_ids)))
    files = {f.id: f for f in result.scalars().all()}

    # Get max position for queue ordering
    pos_result = await db.execute(select(func.coalesce(func.max(PrintQueueItem.position), 0)))
    max_position = pos_result.scalar() or 0

    for file_id in request.file_ids:
        lib_file = files.get(file_id)

        if not lib_file:
            errors.append(AddToQueueError(file_id=file_id, filename="(not found)", error="File not found"))
            continue

        # Validate file is sliced
        if not is_sliced_file(lib_file.filename):
            errors.append(
                AddToQueueError(
                    file_id=file_id,
                    filename=lib_file.filename,
                    error="Not a sliced file. Only .gcode or .gcode.3mf files can be printed.",
                )
            )
            continue

        try:
            # Verify file exists on disk
            file_path = Path(app_settings.base_dir) / lib_file.file_path

            if not file_path.exists():
                errors.append(
                    AddToQueueError(file_id=file_id, filename=lib_file.filename, error="File not found on disk")
                )
                continue

            # Create queue item referencing library file (archive created at print start)
            max_position += 1
            queue_item = PrintQueueItem(
                printer_id=None,  # Unassigned
                library_file_id=file_id,
                position=max_position,
                status="pending",
            )
            db.add(queue_item)

            await db.flush()  # Get queue_item.id

            added.append(
                AddToQueueResult(
                    file_id=file_id,
                    filename=lib_file.filename,
                    queue_item_id=queue_item.id,
                )
            )

        except Exception as e:
            logger.exception("Error adding file %s to queue", file_id)
            errors.append(AddToQueueError(file_id=file_id, filename=lib_file.filename, error=str(e)))

    await db.commit()

    return AddToQueueResponse(added=added, errors=errors)


@router.get("/files/{file_id}/plates")
async def get_library_file_plates(
    file_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get available plates from a multi-plate 3MF library file.

    Returns a list of plates with their index, name, thumbnail availability,
    and filament requirements. For single-plate exports, returns a single plate.
    """
    import json

    import defusedxml.ElementTree as ET

    # Get the library file
    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    lib_file = result.scalar_one_or_none()

    if not lib_file:
        raise HTTPException(status_code=404, detail="File not found")

    file_path = Path(app_settings.base_dir) / lib_file.file_path
    if not file_path.exists():
        raise HTTPException(status_code=404, detail="File not found on disk")

    # Only 3MF files have plates
    if not lib_file.filename.lower().endswith(".3mf"):
        return {"file_id": file_id, "filename": lib_file.filename, "plates": [], "is_multi_plate": False}

    plates = []

    try:
        with zipfile.ZipFile(file_path, "r") as zf:
            namelist = zf.namelist()

            # Find all plate gcode files to determine available plates
            gcode_files = [n for n in namelist if n.startswith("Metadata/plate_") and n.endswith(".gcode")]

            # If no gcode is present (source-only or unsliced), fall back to plate JSON/PNG
            plate_indices: list[int] = []
            if gcode_files:
                # Extract plate indices from gcode filenames
                for gf in gcode_files:
                    try:
                        plate_str = gf[15:-6]  # Remove "Metadata/plate_" and ".gcode"
                        plate_indices.append(int(plate_str))
                    except ValueError:
                        pass  # Skip gcode file with non-numeric plate index
            else:
                plate_json_files = [n for n in namelist if n.startswith("Metadata/plate_") and n.endswith(".json")]
                plate_png_files = [
                    n
                    for n in namelist
                    if n.startswith("Metadata/plate_")
                    and n.endswith(".png")
                    and "_small" not in n
                    and "no_light" not in n
                ]
                plate_name_candidates = plate_json_files + plate_png_files
                plate_re = re.compile(r"^Metadata/plate_(\d+)\.(json|png)$")
                seen_indices: set[int] = set()
                for name in plate_name_candidates:
                    match = plate_re.match(name)
                    if match:
                        try:
                            index = int(match.group(1))
                        except ValueError:
                            continue
                        if index in seen_indices:
                            continue
                        seen_indices.add(index)
                        plate_indices.append(index)

            if not plate_indices:
                # No plate metadata found
                return {"file_id": file_id, "filename": lib_file.filename, "plates": [], "is_multi_plate": False}

            plate_indices.sort()

            # Parse model_settings.config for plate names + object assignments
            plate_names = {}
            plate_object_ids: dict[int, list[str]] = {}
            object_names_by_id: dict[str, str] = {}
            if "Metadata/model_settings.config" in namelist:
                try:
                    model_content = zf.read("Metadata/model_settings.config").decode()
                    model_root = ET.fromstring(model_content)
                    for obj_elem in model_root.findall(".//object"):
                        obj_id = obj_elem.get("id")
                        if not obj_id:
                            continue
                        name_meta = obj_elem.find("metadata[@key='name']")
                        obj_name = name_meta.get("value") if name_meta is not None else None
                        if obj_name:
                            object_names_by_id[obj_id] = obj_name

                    for plate_elem in model_root.findall(".//plate"):
                        plater_id = None
                        plater_name = None
                        for meta in plate_elem.findall("metadata"):
                            key = meta.get("key")
                            value = meta.get("value")
                            if key == "plater_id" and value:
                                try:
                                    plater_id = int(value)
                                except ValueError:
                                    pass  # Ignore plate with non-numeric plater_id
                            elif key == "plater_name" and value:
                                plater_name = value.strip()
                        if plater_id is not None and plater_name:
                            plate_names[plater_id] = plater_name

                        if plater_id is not None:
                            for instance_elem in plate_elem.findall("model_instance"):
                                for inst_meta in instance_elem.findall("metadata"):
                                    if inst_meta.get("key") == "object_id":
                                        obj_id = inst_meta.get("value")
                                        if not obj_id:
                                            continue
                                        plate_object_ids.setdefault(plater_id, [])
                                        if obj_id not in plate_object_ids[plater_id]:
                                            plate_object_ids[plater_id].append(obj_id)
                except Exception:
                    pass  # model_settings.config is optional; skip if missing or malformed

            # Parse slice_info.config for plate metadata
            plate_metadata = {}
            if "Metadata/slice_info.config" in namelist:
                content = zf.read("Metadata/slice_info.config").decode()
                root = ET.fromstring(content)

                for plate_elem in root.findall(".//plate"):
                    plate_info = {"filaments": [], "prediction": None, "weight": None, "name": None, "objects": []}

                    plate_index = None
                    for meta in plate_elem.findall("metadata"):
                        key = meta.get("key")
                        value = meta.get("value")
                        if key == "index" and value:
                            try:
                                plate_index = int(value)
                            except ValueError:
                                pass  # Ignore plate with non-numeric index
                        elif key == "prediction" and value:
                            try:
                                plate_info["prediction"] = int(value)
                            except ValueError:
                                pass  # Leave prediction as None if not a valid integer
                        elif key == "weight" and value:
                            try:
                                plate_info["weight"] = float(value)
                            except ValueError:
                                pass  # Leave weight as None if not a valid number

                    # Get filaments used in this plate
                    for filament_elem in plate_elem.findall("filament"):
                        filament_id = filament_elem.get("id")
                        filament_type = filament_elem.get("type", "")
                        filament_color = filament_elem.get("color", "")
                        used_g = filament_elem.get("used_g", "0")
                        used_m = filament_elem.get("used_m", "0")

                        try:
                            used_grams = float(used_g)
                        except (ValueError, TypeError):
                            used_grams = 0

                        if used_grams > 0 and filament_id:
                            plate_info["filaments"].append(
                                {
                                    "slot_id": int(filament_id),
                                    "type": filament_type,
                                    "color": filament_color,
                                    "used_grams": round(used_grams, 1),
                                    "used_meters": float(used_m) if used_m else 0,
                                }
                            )

                    plate_info["filaments"].sort(key=lambda x: x["slot_id"])

                    # Collect object names
                    for obj_elem in plate_elem.findall("object"):
                        obj_name = obj_elem.get("name")
                        if obj_name and obj_name not in plate_info["objects"]:
                            plate_info["objects"].append(obj_name)

                    # Set plate name
                    if plate_index is not None:
                        custom_name = plate_names.get(plate_index)
                        if custom_name:
                            plate_info["name"] = custom_name
                        elif plate_info["objects"]:
                            plate_info["name"] = plate_info["objects"][0]
                        plate_metadata[plate_index] = plate_info

            # Parse plate_*.json for object lists when slice_info is missing
            plate_json_objects: dict[int, list[str]] = {}
            for name in namelist:
                match = re.match(r"^Metadata/plate_(\d+)\.json$", name)
                if not match:
                    continue
                try:
                    plate_index = int(match.group(1))
                except ValueError:
                    continue
                try:
                    payload = json.loads(zf.read(name).decode())
                    bbox_objects = payload.get("bbox_objects", [])
                    names: list[str] = []
                    for obj in bbox_objects:
                        obj_name = obj.get("name") if isinstance(obj, dict) else None
                        if obj_name and obj_name not in names:
                            names.append(obj_name)
                    if names:
                        plate_json_objects[plate_index] = names
                except Exception:
                    continue

            # Build plate list
            for idx in plate_indices:
                meta = plate_metadata.get(idx, {})
                has_thumbnail = f"Metadata/plate_{idx}.png" in namelist
                objects = meta.get("objects", [])
                if not objects:
                    objects = plate_json_objects.get(idx, [])
                if not objects and plate_object_ids.get(idx):
                    objects = [
                        object_names_by_id.get(obj_id, f"Object {obj_id}") for obj_id in plate_object_ids.get(idx, [])
                    ]

                plate_name = meta.get("name")
                if not plate_name:
                    plate_name = plate_names.get(idx)
                if not plate_name and objects:
                    plate_name = objects[0]

                plates.append(
                    {
                        "index": idx,
                        "name": plate_name,
                        "objects": objects,
                        "object_count": len(objects),
                        "has_thumbnail": has_thumbnail,
                        "thumbnail_url": f"/api/v1/library/files/{file_id}/plate-thumbnail/{idx}"
                        if has_thumbnail
                        else None,
                        "print_time_seconds": meta.get("prediction"),
                        "filament_used_grams": meta.get("weight"),
                        "filaments": meta.get("filaments", []),
                    }
                )

    except Exception as e:
        logger.warning("Failed to parse plates from library file %s: %s", file_id, e)

    return {
        "file_id": file_id,
        "filename": lib_file.filename,
        "plates": plates,
        "is_multi_plate": len(plates) > 1,
    }


@router.get("/files/{file_id}/plate-thumbnail/{plate_index}")
async def get_library_file_plate_thumbnail(
    file_id: int,
    plate_index: int,
    db: AsyncSession = Depends(get_db),
    _: None = RequireCameraStreamTokenIfAuthEnabled,
):
    """Get the thumbnail image for a specific plate from a library file."""
    from starlette.responses import Response

    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    lib_file = result.scalar_one_or_none()

    if not lib_file:
        raise HTTPException(status_code=404, detail="File not found")

    file_path = Path(app_settings.base_dir) / lib_file.file_path
    if not file_path.exists():
        raise HTTPException(status_code=404, detail="File not found on disk")

    try:
        with zipfile.ZipFile(file_path, "r") as zf:
            thumb_path = f"Metadata/plate_{plate_index}.png"
            if thumb_path in zf.namelist():
                data = zf.read(thumb_path)
                return Response(content=data, media_type="image/png")
    except Exception:
        pass  # Archive unreadable or thumbnail missing; fall through to 404

    raise HTTPException(status_code=404, detail=f"Thumbnail for plate {plate_index} not found")


async def _try_preview_slice_filaments(
    db: AsyncSession,
    *,
    kind: str,
    source_id: int,
    plate_id: int,
    file_path: Path,
) -> list[dict] | None:
    """Run a preview slice via the user's configured sidecar. Same shape as
    the matching helper in archives.py — see that module for rationale."""
    from backend.app.api.routes.settings import get_setting
    from backend.app.services.slice_preview import get_preview_filaments

    preferred = (await get_setting(db, "preferred_slicer")) or "bambu_studio"
    if preferred == "orcaslicer":
        configured = await get_setting(db, "orcaslicer_api_url")
        api_url = (configured or app_settings.slicer_api_url).strip()
    elif preferred == "bambu_studio":
        configured = await get_setting(db, "bambu_studio_api_url")
        api_url = (configured or app_settings.bambu_studio_api_url).strip()
    else:
        return None
    if not api_url:
        return None

    try:
        file_bytes = file_path.read_bytes()
    except OSError:
        return None
    return await get_preview_filaments(
        kind=kind,
        source_id=source_id,
        plate_id=plate_id,
        file_bytes=file_bytes,
        file_name=file_path.name,
        api_url=api_url,
    )


@router.get("/files/{file_id}/filament-requirements")
async def get_library_file_filament_requirements(
    file_id: int,
    plate_id: int | None = None,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get filament requirements from a library file.

    Parses the 3MF file to extract filament slot IDs, types, colors, and usage.
    This enables AMS slot assignment when printing from the file manager.

    Args:
        file_id: The library file ID
        plate_id: Optional plate index to get filaments for a specific plate
    """
    import defusedxml.ElementTree as ET

    # Get the library file
    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    lib_file = result.scalar_one_or_none()

    if not lib_file:
        raise HTTPException(status_code=404, detail="File not found")

    # Get the full file path
    file_path = Path(app_settings.base_dir) / lib_file.file_path

    if not file_path.exists():
        raise HTTPException(status_code=404, detail="File not found on disk")

    # Only 3MF files have parseable filament info
    if not lib_file.filename.lower().endswith(".3mf"):
        return {"file_id": file_id, "filename": lib_file.filename, "plate_id": plate_id, "filaments": []}

    filaments = []

    try:
        with zipfile.ZipFile(file_path, "r") as zf:
            # Parse slice_info.config for filament requirements
            if "Metadata/slice_info.config" in zf.namelist():
                content = zf.read("Metadata/slice_info.config").decode()
                root = ET.fromstring(content)

                if plate_id is not None:
                    # Find filaments for specific plate
                    for plate_elem in root.findall(".//plate"):
                        # Check if this is the requested plate
                        plate_index = None
                        for meta in plate_elem.findall("metadata"):
                            if meta.get("key") == "index":
                                try:
                                    plate_index = int(meta.get("value", ""))
                                except ValueError:
                                    pass  # Skip plate with non-numeric index value
                                break

                        if plate_index == plate_id:
                            # Extract filaments from this plate
                            for filament_elem in plate_elem.findall("filament"):
                                filament_id = filament_elem.get("id")
                                filament_type = filament_elem.get("type", "")
                                filament_color = filament_elem.get("color", "")
                                used_g = filament_elem.get("used_g", "0")
                                used_m = filament_elem.get("used_m", "0")

                                tray_info_idx = filament_elem.get("tray_info_idx", "")

                                try:
                                    used_grams = float(used_g)
                                except (ValueError, TypeError):
                                    used_grams = 0

                                if used_grams > 0 and filament_id:
                                    filaments.append(
                                        {
                                            "slot_id": int(filament_id),
                                            "type": filament_type,
                                            "color": filament_color,
                                            "used_grams": round(used_grams, 1),
                                            "used_meters": float(used_m) if used_m else 0,
                                            "tray_info_idx": tray_info_idx,
                                        }
                                    )
                            break
                else:
                    # Extract all filaments with used_g > 0 (for single-plate or overview)
                    for filament_elem in root.findall(".//filament"):
                        filament_id = filament_elem.get("id")
                        filament_type = filament_elem.get("type", "")
                        filament_color = filament_elem.get("color", "")
                        used_g = filament_elem.get("used_g", "0")
                        used_m = filament_elem.get("used_m", "0")

                        tray_info_idx = filament_elem.get("tray_info_idx", "")

                        try:
                            used_grams = float(used_g)
                        except (ValueError, TypeError):
                            used_grams = 0

                        if used_grams > 0 and filament_id:
                            filaments.append(
                                {
                                    "slot_id": int(filament_id),
                                    "type": filament_type,
                                    "color": filament_color,
                                    "used_grams": round(used_grams, 1),
                                    "used_meters": float(used_m) if used_m else 0,
                                    "tray_info_idx": tray_info_idx,
                                }
                            )

            # Unsliced project files: slice_info has nothing usable. Try a
            # preview-slice via the sidecar — see archives.py for full
            # rationale. Cached per (kind, id, plate, content_hash).
            if not filaments and plate_id is not None:
                preview = await _try_preview_slice_filaments(
                    db,
                    kind="library_file",
                    source_id=file_id,
                    plate_id=plate_id,
                    file_path=file_path,
                )
                if preview is not None:
                    filaments = preview

            # Last-resort fallback when preview slicing also can't help (no
            # sidecar configured, slicer errored, etc.). project_settings
            # gives us the full AMS slot config; the plate-extruder filter
            # narrows it to the slots the painted faces reference.
            if not filaments:
                project_filaments = extract_project_filaments_from_3mf(zf)
                if plate_id is not None and project_filaments:
                    used_slots = extract_plate_extruder_set_from_3mf(zf, plate_id)
                    if used_slots:
                        filaments = [f for f in project_filaments if f["slot_id"] in used_slots]
                    else:
                        # No extruder metadata anywhere — return the full
                        # project list rather than zero so the user still
                        # gets to pick (over-rendering > under-rendering).
                        filaments = project_filaments
                elif project_filaments:
                    filaments = project_filaments

            # Sort by slot ID
            filaments.sort(key=lambda x: x["slot_id"])

            # Enrich with nozzle mapping for dual-nozzle printers
            nozzle_mapping = extract_nozzle_mapping_from_3mf(zf)
            if nozzle_mapping:
                for filament in filaments:
                    filament["nozzle_id"] = nozzle_mapping.get(filament["slot_id"])

    except Exception as e:
        logger.warning("Failed to parse filament requirements from library file %s: %s", file_id, e)

    return {
        "file_id": file_id,
        "filename": lib_file.filename,
        "plate_id": plate_id,
        "filaments": filaments,
    }


_STRIPPABLE_3MF_CONFIGS = frozenset(
    {
        # Settings dump used by --load-settings validation; the CLI tries to
        # match its sentinel values (`prime_tower_brim_width: -1`, empty
        # arrays) against the supplied profile and rejects out-of-range.
        "Metadata/project_settings.config",
        # Per-object settings overrides referencing the source plate's
        # filament IDs / printer IDs. When the user picks a different
        # printer / filament triplet, the IDs no longer resolve and the
        # CLI exits non-zero on input validation.
        "Metadata/model_settings.config",
        # Slicer-version + plate-config + filament-mapping snapshot from
        # the original slice. Includes the original printer model and
        # filament references; mismatches against `--load-settings`
        # consistently surfaced as `Slicer CLI failed (500)` for every
        # 3MF in production. Removing it lets the CLI build a fresh slice
        # plan from the supplied profile triplet.
        "Metadata/slice_info.config",
        # Multi-part / split-mesh metadata referencing object IDs from the
        # original slice. Strip for the same reason — preserves the geometry
        # in `3D/3dmodel.model` while dropping the orphan references.
        "Metadata/cut_information.xml",
    }
)


def _strip_3mf_embedded_settings(zip_bytes: bytes) -> bytes:
    """Remove embedded slicer-config metadata from a 3MF.

    Bambuddy supplies the slicer profile triplet via the sidecar's
    ``--load-settings`` path; the 3MF's embedded settings would otherwise be
    validated by the CLI first and can fail with sentinel-value range
    checks (`prime_tower_brim_width: -1 not in range`, etc.) regardless of
    what we pass via ``--load-settings``. Stripping the embedded configs
    forces the CLI to use the supplied profiles only. Geometry
    (``3D/3dmodel.model``), thumbnails, color, and multi-part data inside
    the 3MF are preserved.

    The set of strippable filenames is centralised in
    ``_STRIPPABLE_3MF_CONFIGS`` — see that constant for the per-file
    rationale. Project-settings alone wasn't enough: real-world Bambu
    Studio 3MFs cross-reference printer / filament IDs from the other
    metadata configs, and any single leftover triggered the validation
    failure that made every profile-driven slice fall back to embedded
    settings.
    """
    from io import BytesIO

    src = BytesIO(zip_bytes)
    dst = BytesIO()
    with zipfile.ZipFile(src, "r") as zin, zipfile.ZipFile(dst, "w", zipfile.ZIP_DEFLATED) as zout:
        for item in zin.infolist():
            if item.filename in _STRIPPABLE_3MF_CONFIGS:
                continue
            zout.writestr(item, zin.read(item.filename))
    return dst.getvalue()


async def _run_slicer_with_fallback(
    db: AsyncSession,
    *,
    model_bytes: bytes,
    model_filename: str,
    request: SliceRequest,
    current_user_id: int | None = None,
):
    """Validate presets, dispatch to the right sidecar, run the slicer with
    the auto-fallback for 3MF inputs whose `--load-settings` path crashes the
    CLI. Returns ``(SliceResult, used_embedded_settings: bool)``. Raises
    ``HTTPException`` for any caller-facing error.

    `current_user_id` is needed to resolve **cloud** presets — the cloud token
    is per-user when auth is enabled. For the legacy / local-only path it can
    be left ``None``.
    """
    from backend.app.api.routes.settings import get_setting
    from backend.app.services.preset_resolver import resolve_preset_ref
    from backend.app.services.slicer_api import (
        SlicerApiServerError,
        SlicerApiService,
        SlicerApiUnavailableError,
        SlicerInputError,
    )

    # Resolve each slot via the source-aware resolver. The schema validator
    # has already normalised legacy `*_preset_id: int` fields into
    # `PresetRef(source='local', id=str(int))`, so all three are guaranteed
    # non-None here.
    user: User | None = None
    if current_user_id is not None:
        user = await db.get(User, current_user_id)

    presets: dict[str, str] = {}
    refs = {
        "printer": request.printer_preset,
        "process": request.process_preset,
    }
    for slot, ref in refs.items():
        assert ref is not None, "schema validator guarantees PresetRef is set"
        presets[slot] = await resolve_preset_ref(db, user, ref, slot)
    # Multi-color: resolve each filament slot in plate order. The schema
    # validator backfilled `filament_presets` from the legacy `filament_preset`
    # field for single-color callers, so this list is always non-empty.
    filament_jsons: list[str] = []
    for ref in request.filament_presets:
        assert ref is not None, "schema validator guarantees filament list is non-None"
        filament_jsons.append(await resolve_preset_ref(db, user, ref, "filament"))

    # Slicer routing — pick the sidecar URL by preferred_slicer.
    # The per-install URL setting (Settings UI → Slicer card) wins; an
    # empty value falls back to the SLICER_API_URL / BAMBU_STUDIO_API_URL
    # env defaults defined in core/config.py.
    preferred = (await get_setting(db, "preferred_slicer")) or "bambu_studio"
    if preferred == "orcaslicer":
        configured = await get_setting(db, "orcaslicer_api_url")
        api_url = (configured or app_settings.slicer_api_url).strip()
    elif preferred == "bambu_studio":
        configured = await get_setting(db, "bambu_studio_api_url")
        api_url = (configured or app_settings.bambu_studio_api_url).strip()
    else:
        raise HTTPException(
            status_code=400,
            detail=f"Unknown preferred_slicer setting: '{preferred}'. Expected 'orcaslicer' or 'bambu_studio'.",
        )

    is_3mf = model_filename.lower().endswith(".3mf")
    primary_bytes = model_bytes
    if is_3mf:
        try:
            primary_bytes = _strip_3mf_embedded_settings(model_bytes)
        except (zipfile.BadZipFile, KeyError) as exc:
            raise HTTPException(status_code=400, detail=f"Source 3MF is corrupt: {exc}") from exc

    used_embedded_settings = False
    service = SlicerApiService(api_url)
    try:
        try:
            result = await service.slice_with_profiles(
                model_bytes=primary_bytes,
                model_filename=model_filename,
                printer_profile_json=presets["printer"],
                process_profile_json=presets["process"],
                filament_profile_jsons=filament_jsons,
                plate=request.plate,
                export_3mf=request.export_3mf,
            )
        except SlicerApiServerError as exc:
            if not is_3mf:
                raise
            logger.warning(
                "Slicer CLI rejected --load-settings for %s (%s); retrying with embedded settings",
                model_filename,
                exc,
            )
            result = await service.slice_without_profiles(
                model_bytes=model_bytes,
                model_filename=model_filename,
                plate=request.plate,
                export_3mf=request.export_3mf,
            )
            used_embedded_settings = True
    except SlicerInputError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    except SlicerApiServerError as exc:
        raise HTTPException(status_code=502, detail=str(exc)) from exc
    except SlicerApiUnavailableError as exc:
        raise HTTPException(status_code=502, detail=str(exc)) from exc
    finally:
        await service.close()

    return result, used_embedded_settings


async def slice_and_persist(
    db: AsyncSession,
    *,
    model_bytes: bytes,
    model_filename: str,
    folder_id: int | None,
    extra_metadata: dict | None,
    request: SliceRequest,
    current_user_id: int | None,
) -> SliceResponse:
    """Slice a model and save the result as a new ``LibraryFile`` in
    ``folder_id`` (same folder as the source by convention).

    Always exports as ``.gcode.3mf`` so the existing library thumbnail
    pipeline works on the new file. Plain ``.gcode`` would have no
    embedded thumbnail to extract.
    """
    from backend.app.services.archive import ThreeMFParser

    library_request = request.model_copy(update={"export_3mf": True})

    result, used_embedded_settings = await _run_slicer_with_fallback(
        db,
        model_bytes=model_bytes,
        model_filename=model_filename,
        request=library_request,
        current_user_id=current_user_id,
    )

    base_name = model_filename.rsplit(".", 1)[0]
    out_filename = f"{base_name}.gcode.3mf"
    unique_name = f"{uuid.uuid4().hex}.gcode.3mf"
    out_path = get_library_files_dir() / unique_name
    out_path.write_bytes(result.content)

    # Extract thumbnail from the produced 3MF so the library card shows a
    # preview. Failures here aren't fatal — the file is still useful
    # without a thumbnail.
    thumbnail_relative: str | None = None
    parsed_metadata: dict = {}
    try:
        parser = ThreeMFParser(str(out_path))
        parsed = parser.parse()
        thumb_data = parsed.get("_thumbnail_data")
        thumb_ext = parsed.get("_thumbnail_ext", ".png")
        if thumb_data:
            thumb_filename = f"{uuid.uuid4().hex}{thumb_ext}"
            thumb_path = get_library_thumbnails_dir() / thumb_filename
            thumb_path.write_bytes(thumb_data)
            thumbnail_relative = to_relative_path(thumb_path)
        cleaned = _clean_3mf_metadata(parsed)
        if isinstance(cleaned, dict):
            parsed_metadata = cleaned
    except Exception as exc:
        logger.warning("Failed to parse sliced 3MF metadata for %s: %s", out_filename, exc)

    # The parsed 3MF metadata carries a `print_name` lifted from the source
    # file's embedded settings (BambuStudio always sets this; OrcaSlicer
    # often leaves it blank). The FileManager listing prefers print_name
    # over filename for display, which makes a sliced row indistinguishable
    # from its source. Drop print_name so the listing falls back to the
    # actual filename — which already ends in ".gcode.3mf" and self-describes
    # as the sliced output.
    metadata: dict = {k: v for k, v in parsed_metadata.items() if k != "print_name"}
    metadata.update(
        {
            "print_time_seconds": result.print_time_seconds,
            "filament_used_g": result.filament_used_g,
            "filament_used_mm": result.filament_used_mm,
        }
    )
    if used_embedded_settings:
        metadata["used_embedded_settings"] = True
    if extra_metadata:
        metadata.update(extra_metadata)

    new_file = LibraryFile(
        folder_id=folder_id,
        filename=out_filename,
        file_path=to_relative_path(out_path),
        # Sliced output is a `.gcode.3mf` zip with embedded G-code, but the
        # user-facing meaning is "ready-to-print G-code" — using "gcode"
        # gives it the same badge as plain .gcode files and distinguishes
        # it from un-sliced `.3mf` source models.
        file_type="gcode",
        file_size=len(result.content),
        file_hash=hashlib.sha256(result.content).hexdigest(),
        thumbnail_path=thumbnail_relative,
        file_metadata=metadata,
        source_type="sliced",
        created_by_id=current_user_id,
    )
    db.add(new_file)
    await db.commit()
    await db.refresh(new_file)

    return SliceResponse(
        library_file_id=new_file.id,
        name=new_file.filename,
        print_time_seconds=result.print_time_seconds,
        filament_used_g=result.filament_used_g,
        filament_used_mm=result.filament_used_mm,
        used_embedded_settings=used_embedded_settings,
    )


async def slice_and_persist_as_archive(
    db: AsyncSession,
    *,
    model_bytes: bytes,
    model_filename: str,
    request: SliceRequest,
    source_archive,  # PrintArchive — hint kept loose to avoid cyclic import
    current_user_id: int | None,
):
    """Slice a model and save the result as a new ``PrintArchive`` row,
    inheriting printer / project / makerworld metadata from the source
    archive. Always exports as a `.gcode.3mf` so the existing thumbnail
    and plates infrastructure (which expects a zip-shaped 3MF) works on
    the new archive. Returns ``SliceArchiveResponse``.
    """
    from backend.app.models.archive import PrintArchive
    from backend.app.schemas.slicer import SliceArchiveResponse
    from backend.app.services.archive import ThreeMFParser

    # Archive sinks always want a 3MF. The library route still respects the
    # caller's `export_3mf` flag; here we override.
    archive_request = request.model_copy(update={"export_3mf": True})

    result, used_embedded_settings = await _run_slicer_with_fallback(
        db,
        model_bytes=model_bytes,
        model_filename=model_filename,
        request=archive_request,
        current_user_id=current_user_id,
    )

    base_name = model_filename.rsplit(".", 1)[0]
    out_filename = f"{base_name}.gcode.3mf"

    timestamp = datetime.now(timezone.utc).strftime("%Y%m%d_%H%M%S")
    printer_folder = str(source_archive.printer_id) if source_archive.printer_id is not None else "unassigned"
    archive_subdir = f"{timestamp}_{base_name}_sliced"
    archive_dir = app_settings.archive_dir / printer_folder / archive_subdir
    archive_dir.mkdir(parents=True, exist_ok=True)
    out_path = archive_dir / out_filename
    out_path.write_bytes(result.content)

    # Extract a thumbnail from the produced 3MF so the new archive card has
    # a preview. The 3MF parser pulls Metadata/plate_*.png; failures here
    # shouldn't fail the whole slice — the archive row is still useful
    # without a thumbnail.
    thumbnail_path: str | None = None
    parsed_metadata: dict = {}
    try:
        parser = ThreeMFParser(str(out_path))
        parsed = parser.parse()
        thumb_data = parsed.get("_thumbnail_data")
        thumb_ext = parsed.get("_thumbnail_ext", ".png")
        if thumb_data:
            thumb_dest = archive_dir / f"thumbnail{thumb_ext}"
            thumb_dest.write_bytes(thumb_data)
            thumbnail_path = str(thumb_dest.relative_to(app_settings.base_dir))
        parsed_metadata = {k: v for k, v in parsed.items() if not k.startswith("_")}
    except Exception as exc:
        logger.warning("Failed to parse sliced 3MF metadata for %s: %s", out_filename, exc)

    metadata = dict(source_archive.extra_data) if source_archive.extra_data else {}
    metadata.update(parsed_metadata)
    metadata.update(
        {
            "sliced_from_archive_id": source_archive.id,
            "print_time_seconds": result.print_time_seconds,
            "filament_used_g": result.filament_used_g,
            "filament_used_mm": result.filament_used_mm,
        }
    )
    if used_embedded_settings:
        metadata["used_embedded_settings"] = True

    # Prefer the actually-used filament list from the sliced output's
    # slice_info.config (parsed_metadata.filament_* — only entries with
    # used_g > 0). Falling back to the source_archive's list would
    # surface every project-wide AMS slot, including ones the picked
    # plate doesn't use (16+ swatches on the card for a 2-color print).
    new_filament_type = parsed_metadata.get("filament_type") or source_archive.filament_type
    new_filament_color = parsed_metadata.get("filament_color") or source_archive.filament_color

    new_archive = PrintArchive(
        printer_id=source_archive.printer_id,
        project_id=source_archive.project_id,
        filename=out_filename,
        file_path=str(out_path.relative_to(app_settings.base_dir)),
        file_size=len(result.content),
        content_hash=hashlib.sha256(result.content).hexdigest(),
        thumbnail_path=thumbnail_path,
        # Inherit identity from the source archive so the new entry shows
        # up alongside its sibling in the archives list.
        print_name=(source_archive.print_name or base_name) + " (re-sliced)",
        print_time_seconds=result.print_time_seconds,
        filament_used_grams=result.filament_used_g or None,
        filament_type=new_filament_type,
        filament_color=new_filament_color,
        layer_height=source_archive.layer_height,
        nozzle_diameter=source_archive.nozzle_diameter,
        sliced_for_model=source_archive.sliced_for_model,
        makerworld_url=source_archive.makerworld_url,
        designer=source_archive.designer,
        # Sliced-but-not-printed: keep status default ("completed") so it
        # surfaces in the normal archives list, but do not stamp
        # started/completed_at — the user hasn't actually printed it yet.
        extra_data=metadata,
        created_by_id=current_user_id,
    )
    db.add(new_archive)
    await db.commit()
    await db.refresh(new_archive)

    return SliceArchiveResponse(
        archive_id=new_archive.id,
        name=new_archive.print_name or out_filename,
        print_time_seconds=result.print_time_seconds,
        filament_used_g=result.filament_used_g,
        filament_used_mm=result.filament_used_mm,
        used_embedded_settings=used_embedded_settings,
    )


@router.post("/files/{file_id}/slice", status_code=202)
async def slice_library_file(
    file_id: int,
    request: SliceRequest,
    db: AsyncSession = Depends(get_db),
    current_user: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_UPLOAD)),
):
    """Enqueue a slice job for a library file. Returns 202 + job_id; the
    slice runs in the background, the caller polls `GET /slice-jobs/{id}`.
    """
    from backend.app.core.database import async_session
    from backend.app.services.slice_dispatch import (
        http_exception_to_job_error,
        slice_dispatch,
    )

    src_result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    lib_file = src_result.scalar_one_or_none()
    if not lib_file:
        raise HTTPException(status_code=404, detail="File not found")

    src_lower = (lib_file.filename or "").lower()
    if not (
        src_lower.endswith(".stl")
        or src_lower.endswith(".3mf")
        or src_lower.endswith(".step")
        or src_lower.endswith(".stp")
    ):
        raise HTTPException(status_code=400, detail="Source file must be STL, 3MF, or STEP")

    src_path = Path(app_settings.base_dir) / lib_file.file_path
    if not src_path.exists():
        raise HTTPException(status_code=404, detail="Source file missing on disk")

    # Capture inputs the bg task needs — the request DB session is closed
    # before the background task runs.
    model_bytes = src_path.read_bytes()
    folder_id = lib_file.folder_id
    source_lib_file_id = lib_file.id
    user_id = current_user.id if current_user else None

    # If the source has a `print_name` in its metadata (BambuStudio always
    # sets this; OrcaSlicer often leaves it blank), derive the sliced
    # output's filename from it instead of the raw filename. The source
    # row's display already prefers print_name, so the sliced row's
    # filename ("Piggo the piggy bank.gcode.3mf") will match the source's
    # display name ("Piggo the piggy bank") with the gcode extension added.
    src_print_name = None
    if lib_file.file_metadata:
        candidate = lib_file.file_metadata.get("print_name")
        if isinstance(candidate, str) and candidate.strip():
            src_print_name = candidate.strip()
    src_ext = Path(lib_file.filename).suffix.lower() or ".3mf"
    model_filename = f"{src_print_name}{src_ext}" if src_print_name else lib_file.filename

    async def _run():
        async with async_session() as task_db:
            try:
                response = await slice_and_persist(
                    task_db,
                    model_bytes=model_bytes,
                    model_filename=model_filename,
                    folder_id=folder_id,
                    extra_metadata={"sliced_from_library_file_id": source_lib_file_id},
                    request=request,
                    current_user_id=user_id,
                )
            except HTTPException as exc:
                raise http_exception_to_job_error(exc) from exc
        return response.model_dump()

    job = await slice_dispatch.enqueue(
        kind="library_file",
        source_id=lib_file.id,
        source_name=lib_file.filename,
        run=_run,
    )
    return {
        "job_id": job.id,
        "status": job.status,
        "status_url": f"/api/v1/slice-jobs/{job.id}",
    }


@router.post("/files/{file_id}/print")
async def print_library_file(
    file_id: int,
    printer_id: int,
    body: FilePrintRequest | None = None,
    db: AsyncSession = Depends(get_db),
    current_user: User | None = Depends(require_permission_if_auth_enabled(Permission.PRINTERS_CONTROL)),
):
    """Dispatch a library file for send/start on a printer.

    The actual send/start work is handled asynchronously by background
    dispatch so the UI can continue immediately.

    Only sliced files (.gcode or .gcode.3mf) can be printed.
    """
    from backend.app.models.printer import Printer
    from backend.app.services.background_dispatch import DispatchEnqueueRejected, background_dispatch
    from backend.app.services.printer_manager import printer_manager

    # Use defaults if no body provided
    if body is None:
        body = FilePrintRequest()

    # Get the library file
    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    lib_file = result.scalar_one_or_none()

    if not lib_file:
        raise HTTPException(status_code=404, detail="File not found")

    # Validate file is sliced
    if not is_sliced_file(lib_file.filename):
        raise HTTPException(
            status_code=400,
            detail="Not a sliced file. Only .gcode or .gcode.3mf files can be printed.",
        )

    # Get the full file path
    file_path = Path(app_settings.base_dir) / lib_file.file_path

    if not file_path.exists():
        raise HTTPException(status_code=404, detail="File not found on disk")

    # Get printer
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(status_code=404, detail="Printer not found")

    # Check printer is connected
    if not printer_manager.is_connected(printer_id):
        raise HTTPException(status_code=400, detail="Printer is not connected")

    # Validate project exists before dispatching so a bogus ID yields 404, not a FK-constraint 500
    if body.project_id is not None:
        project_result = await db.execute(select(Project).where(Project.id == body.project_id))
        if not project_result.scalar_one_or_none():
            raise HTTPException(status_code=404, detail="Project not found")

    plate_name = body.plate_name
    if not plate_name and body.plate_id is not None:
        plate_name = f"Plate {body.plate_id}"

    dispatch_source_name = lib_file.filename
    if plate_name:
        dispatch_source_name = f"{lib_file.filename} • {plate_name}"

    try:
        dispatch_result = await background_dispatch.dispatch_print_library_file(
            file_id=file_id,
            filename=dispatch_source_name,
            printer_id=printer_id,
            printer_name=printer.name,
            options=body.model_dump(exclude_none=True, exclude={"cleanup_library_after_dispatch"}),
            project_id=body.project_id,
            requested_by_user_id=current_user.id if current_user else None,
            requested_by_username=current_user.username if current_user else None,
            cleanup_library_after_dispatch=body.cleanup_library_after_dispatch,
        )
    except DispatchEnqueueRejected as e:
        raise HTTPException(status_code=409, detail=str(e)) from e

    return {
        "status": "dispatched",
        "printer_id": printer_id,
        "archive_id": None,
        "filename": lib_file.filename,
        "dispatch_job_id": dispatch_result["dispatch_job_id"],
        "dispatch_position": dispatch_result["dispatch_position"],
    }


# ============ File Detail Endpoints ============


@router.get("/files/{file_id}", response_model=FileResponseSchema)
async def get_file(
    file_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get a file by ID with full details."""
    result = await db.execute(
        LibraryFile.active().options(selectinload(LibraryFile.created_by)).where(LibraryFile.id == file_id)
    )
    file = result.scalar_one_or_none()

    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    # Get folder name
    folder_name = None
    if file.folder_id:
        folder_result = await db.execute(select(LibraryFolder.name).where(LibraryFolder.id == file.folder_id))
        folder_name = folder_result.scalar()

    # Get project name
    project_name = None
    if file.project_id:
        project_result = await db.execute(select(Project.name).where(Project.id == file.project_id))
        project_name = project_result.scalar()

    # Get duplicates
    duplicates = []
    duplicate_count = 0
    if file.file_hash:
        dup_result = await db.execute(
            select(LibraryFile, LibraryFolder.name)
            .outerjoin(LibraryFolder, LibraryFile.folder_id == LibraryFolder.id)
            .where(
                LibraryFile.file_hash == file.file_hash,
                LibraryFile.id != file.id,
                LibraryFile.deleted_at.is_(None),
            )
        )
        for dup_file, dup_folder_name in dup_result.all():
            duplicates.append(
                FileDuplicate(
                    id=dup_file.id,
                    filename=dup_file.filename,
                    folder_id=dup_file.folder_id,
                    folder_name=dup_folder_name,
                    created_at=dup_file.created_at,
                )
            )
        duplicate_count = len(duplicates)

    # Extract key metadata fields
    print_name = None
    print_time = None
    filament_grams = None
    sliced_for_model = None
    if file.file_metadata:
        print_name = file.file_metadata.get("print_name")
        print_time = file.file_metadata.get("print_time_seconds")
        filament_grams = file.file_metadata.get("filament_used_grams")
        sliced_for_model = file.file_metadata.get("sliced_for_model")

    return FileResponseSchema(
        id=file.id,
        folder_id=file.folder_id,
        folder_name=folder_name,
        project_id=file.project_id,
        project_name=project_name,
        filename=file.filename,
        file_path=file.file_path,
        file_type=file.file_type,
        file_size=file.file_size,
        file_hash=file.file_hash,
        thumbnail_path=file.thumbnail_path,
        metadata=file.file_metadata,
        print_count=file.print_count,
        last_printed_at=file.last_printed_at,
        notes=file.notes,
        duplicates=duplicates if duplicates else None,
        duplicate_count=duplicate_count,
        created_by_id=file.created_by_id,
        created_by_username=file.created_by.username if file.created_by else None,
        created_at=file.created_at,
        updated_at=file.updated_at,
        print_name=print_name,
        print_time_seconds=print_time,
        filament_used_grams=filament_grams,
        sliced_for_model=sliced_for_model,
    )


@router.put("/files/{file_id}", response_model=FileResponseSchema)
async def update_file(
    file_id: int,
    data: FileUpdate,
    db: AsyncSession = Depends(get_db),
    auth_result: tuple[User | None, bool] = Depends(
        require_ownership_permission(
            Permission.LIBRARY_UPDATE_ALL,
            Permission.LIBRARY_UPDATE_OWN,
        )
    ),
):
    """Update a file's metadata."""
    user, can_modify_all = auth_result

    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    file = result.scalar_one_or_none()

    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    # Ownership check
    if not can_modify_all:
        if file.created_by_id != user.id:
            raise HTTPException(status_code=403, detail="You can only update your own files")

    if data.filename is not None:
        # Validate filename doesn't contain path separators
        if "/" in data.filename or "\\" in data.filename:
            raise HTTPException(status_code=400, detail="Filename cannot contain path separators")
        file.filename = data.filename
        # Also update print_name in file_metadata so the display name matches
        if file.file_metadata and "print_name" in file.file_metadata:
            file.file_metadata = {**file.file_metadata, "print_name": data.filename}

    if data.folder_id is not None:
        if data.folder_id == 0:
            file.folder_id = None
        else:
            # Verify folder exists
            folder_result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == data.folder_id))
            if not folder_result.scalar_one_or_none():
                raise HTTPException(status_code=404, detail="Folder not found")
            file.folder_id = data.folder_id

    if data.project_id is not None:
        if data.project_id == 0:
            file.project_id = None
        else:
            # Verify project exists
            project_result = await db.execute(select(Project).where(Project.id == data.project_id))
            if not project_result.scalar_one_or_none():
                raise HTTPException(status_code=404, detail="Project not found")
            file.project_id = data.project_id

    if data.notes is not None:
        file.notes = data.notes if data.notes else None

    await db.commit()
    await db.refresh(file)

    # Return full response (reuse get_file logic)
    return await get_file(file_id, db)


@router.delete("/files/{file_id}")
async def delete_file(
    file_id: int,
    db: AsyncSession = Depends(get_db),
    auth_result: tuple[User | None, bool] = Depends(
        require_ownership_permission(
            Permission.LIBRARY_DELETE_ALL,
            Permission.LIBRARY_DELETE_OWN,
        )
    ),
):
    """Move a file to the trash (soft-delete).

    The file's bytes and thumbnail stay on disk until the trash sweeper
    hard-deletes the row after the retention window (see #1008). External
    files skip the trash entirely — they can't be restored from disk and the
    underlying file is outside Bambuddy's control, so we just drop the DB
    record and thumbnail.
    """
    user, can_modify_all = auth_result

    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    file = result.scalar_one_or_none()

    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    # Ownership check
    if not can_modify_all:
        if file.created_by_id != user.id:
            raise HTTPException(status_code=403, detail="You can only delete your own files")

    if file.is_external:
        # External files bypass the trash — just drop the DB row + our thumbnail.
        abs_thumb_path = to_absolute_path(file.thumbnail_path)
        if abs_thumb_path and abs_thumb_path.exists():
            try:
                abs_thumb_path.unlink()
            except OSError as e:
                logger.warning("Failed to delete thumbnail from disk: %s", e)
        await db.delete(file)
        await db.commit()
        return {"status": "success", "message": "File deleted", "trashed": False}

    # Managed file: soft-delete. Sweeper removes bytes + thumbnail after retention.
    file.deleted_at = datetime.now(timezone.utc)
    await db.commit()
    return {"status": "success", "message": "File moved to trash", "trashed": True}


# ============ File Content Endpoints ============


@router.get("/files/{file_id}/download")
async def download_file(
    file_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Download a file."""
    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    file = result.scalar_one_or_none()

    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    abs_path = to_absolute_path(file.file_path)
    if not abs_path or not abs_path.exists():
        raise HTTPException(status_code=404, detail="File not found on disk")

    return FastAPIFileResponse(
        str(abs_path),
        filename=file.filename,
        media_type="application/octet-stream",
    )


@router.post("/files/{file_id}/slicer-token")
async def create_library_slicer_token(
    file_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Create a short-lived download token for opening files in slicer applications.

    Slicer protocol handlers (bambustudioopen://, orcaslicer://) cannot send
    auth headers, so they use this token in the URL path instead.
    """
    from backend.app.core.auth import create_slicer_download_token

    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    file = result.scalar_one_or_none()
    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    token = await create_slicer_download_token("library", file_id)
    return {"token": token}


@router.get("/files/{file_id}/dl/{token}/{filename}")
async def download_library_file_for_slicer(
    file_id: int,
    token: str,
    filename: str,
    db: AsyncSession = Depends(get_db),
):
    """Download a library file using a slicer download token.

    Token-authenticated (no auth headers needed). The token is short-lived
    and single-use, created by POST /files/{file_id}/slicer-token.
    Filename is at the end of the URL so slicers can detect the file format.
    """
    from backend.app.core.auth import verify_slicer_download_token

    if not await verify_slicer_download_token(token, "library", file_id):
        raise HTTPException(status_code=403, detail="Invalid or expired download token")

    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    file = result.scalar_one_or_none()
    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    abs_path = to_absolute_path(file.file_path)
    if not abs_path or not abs_path.exists():
        raise HTTPException(status_code=404, detail="File not found on disk")

    return FastAPIFileResponse(
        str(abs_path),
        filename=file.filename,
        media_type="application/octet-stream",
    )


@router.get("/files/{file_id}/thumbnail")
async def get_thumbnail(
    file_id: int,
    db: AsyncSession = Depends(get_db),
    _: None = RequireCameraStreamTokenIfAuthEnabled,
):
    """Get a file's thumbnail."""
    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    file = result.scalar_one_or_none()

    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    abs_thumb_path = to_absolute_path(file.thumbnail_path)
    if not abs_thumb_path or not abs_thumb_path.exists():
        raise HTTPException(status_code=404, detail="Thumbnail not found")

    # Detect media type from extension
    thumb_ext = abs_thumb_path.suffix.lower()
    media_types = {
        ".png": "image/png",
        ".jpg": "image/jpeg",
        ".jpeg": "image/jpeg",
        ".gif": "image/gif",
        ".webp": "image/webp",
    }
    media_type = media_types.get(thumb_ext, "image/png")

    return FastAPIFileResponse(str(abs_thumb_path), media_type=media_type)


@router.get("/files/{file_id}/gcode")
async def get_gcode(
    file_id: int,
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get gcode for a file (for preview)."""
    result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
    file = result.scalar_one_or_none()

    if not file:
        raise HTTPException(status_code=404, detail="File not found")

    abs_path = to_absolute_path(file.file_path)
    if not abs_path or not abs_path.exists():
        raise HTTPException(status_code=404, detail="File not found on disk")

    if file.file_type == "gcode":
        return FastAPIFileResponse(str(abs_path), media_type="text/plain")
    elif file.file_type == "3mf":
        # Extract gcode from 3mf
        try:
            with zipfile.ZipFile(str(abs_path), "r") as zf:
                # Find gcode file
                gcode_files = [n for n in zf.namelist() if n.endswith(".gcode")]
                if not gcode_files:
                    raise HTTPException(status_code=404, detail="No gcode found in 3MF file")
                gcode_content = zf.read(gcode_files[0])
                from fastapi.responses import Response

                return Response(content=gcode_content, media_type="text/plain")
        except zipfile.BadZipFile:
            raise HTTPException(status_code=400, detail="Invalid 3MF file")
    else:
        raise HTTPException(status_code=400, detail="Unsupported file type")


# ============ Bulk Operations ============


@router.post("/files/move")
async def move_files(
    data: FileMoveRequest,
    db: AsyncSession = Depends(get_db),
    auth_result: tuple[User | None, bool] = Depends(
        require_ownership_permission(
            Permission.LIBRARY_UPDATE_ALL,
            Permission.LIBRARY_UPDATE_OWN,
        )
    ),
):
    """Move multiple files to a folder.

    Cross-boundary moves (managed ↔ external, or external ↔ external)
    physically relocate the bytes — see ``_move_file_bytes``. Same-boundary
    moves stay DB-only because the file's on-disk location doesn't depend
    on which managed folder owns it.

    Files not owned by the user are skipped (unless user has ``*_all``
    permission). Each skip carries a structured reason so the UI can
    surface "5 of 10 files were skipped: 3 had filename collisions on
    the NAS, 2 are no longer on disk" rather than a blank "skipped: 5".
    """
    user, can_modify_all = auth_result

    # Verify folder exists if specified
    target_folder: LibraryFolder | None = None
    if data.folder_id is not None:
        folder_result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == data.folder_id))
        target_folder = folder_result.scalar_one_or_none()
        if not target_folder:
            raise HTTPException(status_code=404, detail="Folder not found")
        if target_folder.is_external and target_folder.external_readonly:
            raise HTTPException(status_code=403, detail="Cannot move files to a read-only external folder")

    target_is_external = target_folder is not None and target_folder.is_external

    moved = 0
    skipped = 0
    skipped_reasons: list[dict] = []

    for file_id in data.file_ids:
        result = await db.execute(
            LibraryFile.active().options(selectinload(LibraryFile.folder)).where(LibraryFile.id == file_id)
        )
        file = result.scalar_one_or_none()
        if not file:
            continue
        # Ownership check
        if not can_modify_all and file.created_by_id != user.id:
            skipped += 1
            skipped_reasons.append({"file_id": file_id, "code": "not_owner", "reason": "not the file owner"})
            continue

        # No bytes need to move when both ends are managed (same-boundary).
        if not file.is_external and not target_is_external:
            file.folder_id = data.folder_id
            moved += 1
            continue

        # Block moves out of a read-only external mount. The user only has
        # read access to the source, and a move is semantically a delete on
        # the source — which a read-only mount can't fulfil. Without this
        # guard we'd succeed at copying to the target, fail to unlink the
        # source, and the same file would now exist in two places (with
        # the DB pointing at only one).
        if file.is_external and file.folder is not None and file.folder.external_readonly:
            skipped += 1
            skipped_reasons.append(
                {"file_id": file_id, "code": "source_readonly", "reason": "source is on a read-only external folder"}
            )
            continue

        # Otherwise relocate the bytes, then update the DB row to match.
        try:
            new_file_path = _move_file_bytes(file, target_folder)
        except _MoveSkip as e:
            skipped += 1
            skipped_reasons.append({"file_id": file_id, "code": e.code, "reason": e.reason})
            continue

        file.is_external = target_is_external
        file.folder_id = data.folder_id
        file.file_path = new_file_path
        # External rows historically carry `file_hash=None` (scan skips
        # hashing). When pulling an external file into managed storage,
        # compute the hash so dedup detection works for future uploads
        # of the same content.
        if not target_is_external and file.file_hash is None:
            try:
                abs_path = to_absolute_path(new_file_path)
                if abs_path:
                    file.file_hash = calculate_file_hash(abs_path)
            except OSError:
                pass  # leave hash null; dedup just won't match this row
        moved += 1

    await db.commit()

    return {
        "status": "success",
        "moved": moved,
        "skipped": skipped,
        "skipped_reasons": skipped_reasons,
    }


@router.post("/bulk-delete", response_model=BulkDeleteResponse)
async def bulk_delete(
    data: BulkDeleteRequest,
    db: AsyncSession = Depends(get_db),
    auth_result: tuple[User | None, bool] = Depends(
        require_ownership_permission(
            Permission.LIBRARY_DELETE_ALL,
            Permission.LIBRARY_DELETE_OWN,
        )
    ),
):
    """Delete multiple files and/or folders.

    Files not owned by the user are skipped (unless user has *_all permission).
    """
    user, can_modify_all = auth_result
    deleted_files = 0
    deleted_folders = 0
    skipped_files = 0

    # Delete files first. Managed files go to trash (sweeper hard-deletes bytes
    # later); external files bypass trash since their disk state is outside our
    # control and can't be restored from trash anyway.
    now = datetime.now(timezone.utc)
    for file_id in data.file_ids:
        result = await db.execute(LibraryFile.active().where(LibraryFile.id == file_id))
        file = result.scalar_one_or_none()
        if not file:
            continue
        if not can_modify_all and file.created_by_id != user.id:
            skipped_files += 1
            continue

        if file.is_external:
            abs_thumb_path = to_absolute_path(file.thumbnail_path)
            if abs_thumb_path and abs_thumb_path.exists():
                try:
                    abs_thumb_path.unlink()
                except OSError as e:
                    logger.warning("Failed to delete thumbnail from disk: %s", e)
            await db.delete(file)
        else:
            file.deleted_at = now
        deleted_files += 1

    # Delete folders (cascade will handle contents)
    # Note: Folders don't have ownership tracking currently, require *_all permission
    for folder_id in data.folder_ids:
        if not can_modify_all:
            # Users without *_all permission cannot delete folders
            continue

        result = await db.execute(select(LibraryFolder).where(LibraryFolder.id == folder_id))
        folder = result.scalar_one_or_none()
        if folder:
            # Count files that will be deleted
            file_count_result = await db.execute(
                select(func.count(LibraryFile.id)).where(
                    LibraryFile.folder_id == folder_id,
                    LibraryFile.deleted_at.is_(None),
                )
            )
            deleted_files += file_count_result.scalar() or 0
            await db.delete(folder)
            deleted_folders += 1

    await db.commit()

    return BulkDeleteResponse(deleted_files=deleted_files, deleted_folders=deleted_folders)


# ============ Stats Endpoint ============


@router.get("/stats")
async def get_library_stats(
    db: AsyncSession = Depends(get_db),
    _: User | None = Depends(require_permission_if_auth_enabled(Permission.LIBRARY_READ)),
):
    """Get library statistics."""
    # Stats exclude trashed files — users see counts/sizes for what's actually in the library.
    active_only = LibraryFile.deleted_at.is_(None)

    # Total files
    total_files_result = await db.execute(select(func.count(LibraryFile.id)).where(active_only))
    total_files = total_files_result.scalar() or 0

    # Total folders
    total_folders_result = await db.execute(select(func.count(LibraryFolder.id)))
    total_folders = total_folders_result.scalar() or 0

    # Total size
    total_size_result = await db.execute(select(func.sum(LibraryFile.file_size)).where(active_only))
    total_size = total_size_result.scalar() or 0

    # Files by type
    type_result = await db.execute(
        select(LibraryFile.file_type, func.count(LibraryFile.id)).where(active_only).group_by(LibraryFile.file_type)
    )
    files_by_type = dict(type_result.all())

    # Total prints
    total_prints_result = await db.execute(select(func.sum(LibraryFile.print_count)).where(active_only))
    total_prints = total_prints_result.scalar() or 0

    # Disk space info
    library_dir = get_library_dir()
    try:
        disk_stat = shutil.disk_usage(library_dir)
        disk_free_bytes = disk_stat.free
        disk_total_bytes = disk_stat.total
        disk_used_bytes = disk_stat.used
    except OSError:
        disk_free_bytes = 0
        disk_total_bytes = 0
        disk_used_bytes = 0

    return {
        "total_files": total_files,
        "total_folders": total_folders,
        "total_size_bytes": total_size,
        "files_by_type": files_by_type,
        "total_prints": total_prints,
        "disk_free_bytes": disk_free_bytes,
        "disk_total_bytes": disk_total_bytes,
        "disk_used_bytes": disk_used_bytes,
    }