bambuddy/backend/tests/unit/test_usage_tracker.py

"""Unit tests for usage_tracker.py — 3MF-primary filament tracking.

Tests the unified tracking logic: 3MF slicer estimates as primary path,
AMS remain% delta as fallback, per-layer gcode for partial prints,
slot-to-tray mapping resolution, and notification variable formatting.
"""

from datetime import datetime, timedelta, timezone
from types import SimpleNamespace
from unittest.mock import AsyncMock, MagicMock, patch

import pytest

from backend.app.services.usage_tracker import (
    PrintSession,
    _active_sessions,
    _decode_mqtt_mapping,
    _find_3mf_by_filename,
    _match_slots_by_color,
    _track_from_3mf,
    on_print_complete,
    on_print_start,
)


def _make_spool(spool_id=1, label_weight=1000, weight_used=0, tag_uid=None, tray_uuid=None):
    """Create a mock Spool object."""
    spool = MagicMock()
    spool.id = spool_id
    spool.label_weight = label_weight
    spool.weight_used = weight_used
    spool.tag_uid = tag_uid
    spool.tray_uuid = tray_uuid
    spool.last_used = None
    spool.cost_per_kg = None
    spool.material = "PLA"
    return spool


def _make_assignment(spool_id=1, printer_id=1, ams_id=0, tray_id=0):
    """Create a mock SpoolAssignment object."""
    assignment = MagicMock()
    assignment.spool_id = spool_id
    assignment.printer_id = printer_id
    assignment.ams_id = ams_id
    assignment.tray_id = tray_id
    return assignment


def _make_archive(archive_id=1, file_path="archives/1/test.3mf", extra_data=None):
    """Create a mock PrintArchive object."""
    archive = MagicMock()
    archive.id = archive_id
    archive.file_path = file_path
    archive.extra_data = extra_data
    return archive


def _make_queue_item(ams_mapping=None, status="printing", plate_id=None):
    """Create a mock PrintQueueItem object."""
    item = MagicMock()
    item.ams_mapping = ams_mapping
    item.status = status
    item.plate_id = plate_id
    return item


def _mock_db_execute(*return_values):
    """Create a mock db with execute() that returns values in sequence."""
    db = AsyncMock()
    results = []
    for val in return_values:
        result = MagicMock()
        result.scalar_one_or_none.return_value = val
        results.append(result)
    db.execute = AsyncMock(side_effect=results)
    return db


def _mock_db_sequential(responses):
    """Create mock db that returns responses in order."""
    db = AsyncMock()
    call_count = [0]

    async def mock_execute(*args, **kwargs):
        idx = call_count[0]
        call_count[0] += 1
        result = MagicMock()
        if idx < len(responses):
            result.scalar_one_or_none.return_value = responses[idx]
        else:
            result.scalar_one_or_none.return_value = None
        # For cost aggregation queries that use .scalar() instead of .scalar_one_or_none()
        result.scalar.return_value = None
        return result

    db.execute = mock_execute
    return db


class TestOnPrintStart:
    """Tests for on_print_start()."""

    @pytest.fixture(autouse=True)
    def _clear_sessions(self):
        _active_sessions.clear()
        yield
        _active_sessions.clear()

    @pytest.mark.asyncio
    async def test_captures_remain_data(self):
        """Captures AMS remain% at print start."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 80}, {"id": 1, "remain": 50}]}]},
            tray_now=5,
        )

        await on_print_start(1, {"subtask_name": "Benchy"}, printer_manager)

        assert 1 in _active_sessions
        session = _active_sessions[1]
        assert session.print_name == "Benchy"
        assert session.tray_remain_start == {(0, 0): 80, (0, 1): 50}

    @pytest.mark.asyncio
    async def test_captures_tray_now_at_start(self):
        """Captures tray_now at print start for later use in usage tracking."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 80}]}]},
            tray_now=9,
        )

        await on_print_start(1, {"subtask_name": "Test"}, printer_manager)

        assert _active_sessions[1].tray_now_at_start == 9

    @pytest.mark.asyncio
    async def test_tray_now_at_start_255_when_unloaded(self):
        """Captures tray_now=255 when printer has no filament loaded at start."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 80}]}]},
            tray_now=255,
        )

        await on_print_start(1, {"subtask_name": "Test"}, printer_manager)

        assert _active_sessions[1].tray_now_at_start == 255

    @pytest.mark.asyncio
    async def test_creates_session_without_remain(self):
        """Creates session even without valid remain data (for 3MF tracking)."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": -1}]}]},
            tray_now=255,
        )

        await on_print_start(1, {"subtask_name": "Test"}, printer_manager)

        assert 1 in _active_sessions
        assert _active_sessions[1].tray_remain_start == {}


class TestOnPrintComplete:
    """Tests for on_print_complete() — path ordering and interaction."""

    @pytest.fixture(autouse=True)
    def _clear_sessions(self):
        _active_sessions.clear()
        yield
        _active_sessions.clear()

    @pytest.fixture(autouse=True)
    def _mock_get_setting(self):
        with patch(
            "backend.app.api.routes.settings.get_setting",
            new_callable=AsyncMock,
            return_value=None,
        ):
            yield

    @pytest.mark.asyncio
    async def test_bl_spool_uses_3mf(self):
        """BL spool (with tag_uid) is tracked via 3MF, not just AMS delta."""
        spool = _make_spool(spool_id=1, tag_uid="AABB1122", label_weight=1000)
        assignment = _make_assignment(spool_id=1, printer_id=1, ams_id=0, tray_id=0)
        archive = _make_archive(archive_id=10)

        # Setup: session with AMS remain data
        _active_sessions[1] = PrintSession(
            printer_id=1,
            print_name="Benchy",
            started_at=datetime.now(timezone.utc),
            tray_remain_start={(0, 0): 80},
        )

        # Mock printer state: tray_now=0 (AMS0-T0), single filament
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 70}]}]},
            progress=100,
            layer_num=50,
            tray_now=0,
        )

        # db returns: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        filament_usage = [{"slot_id": 1, "used_g": 15.0, "type": "PLA", "color": "#FF0000"}]

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await on_print_complete(
                printer_id=1,
                data={"status": "completed"},
                printer_manager=printer_manager,
                db=db,
                archive_id=10,
            )

        # 3MF path should handle it (BL guard removed)
        assert len(results) >= 1
        assert results[0]["spool_id"] == 1
        assert results[0]["weight_used"] == 15.0

    @pytest.mark.asyncio
    async def test_ams_delta_fallback_no_archive(self):
        """AMS delta tracks consumption when archive_id is None."""
        spool = _make_spool(spool_id=2, label_weight=1000)
        assignment = _make_assignment(spool_id=2)

        _active_sessions[1] = PrintSession(
            printer_id=1,
            print_name="Test",
            started_at=datetime.now(timezone.utc),
            tray_remain_start={(0, 0): 80},
        )

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 70}]}]},
            tray_now=0,
            last_loaded_tray=-1,
        )

        # Pad 2 Nones for _find_3mf_by_filename DB queries (library + archive search),
        # then assignment and spool for the AMS fallback path
        db = _mock_db_sequential([None, None, assignment, spool])

        results = await on_print_complete(
            printer_id=1,
            data={"status": "completed"},
            printer_manager=printer_manager,
            db=db,
            archive_id=None,
        )

        assert len(results) == 1
        assert results[0]["spool_id"] == 2
        # 10% of 1000g = 100g
        assert results[0]["weight_used"] == 100.0
        assert results[0]["percent_used"] == 10

    @pytest.mark.asyncio
    async def test_no_double_tracking(self):
        """When 3MF handles a tray, AMS delta skips it."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1)
        archive = _make_archive(archive_id=10)

        _active_sessions[1] = PrintSession(
            printer_id=1,
            print_name="Benchy",
            started_at=datetime.now(timezone.utc),
            tray_remain_start={(0, 0): 80},
        )

        # tray_now=0 matches the single filament slot
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 70}]}]},
            progress=100,
            layer_num=50,
            tray_now=0,
        )

        # db returns: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        filament_usage = [{"slot_id": 1, "used_g": 15.0, "type": "PLA", "color": "#FF0000"}]

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await on_print_complete(
                printer_id=1,
                data={"status": "completed"},
                printer_manager=printer_manager,
                db=db,
                archive_id=10,
            )

        # Only 1 result (3MF), NOT 2 (3MF + AMS delta)
        assert len(results) == 1
        assert results[0]["weight_used"] == 15.0


class TestTrackFrom3mf:
    """Tests for _track_from_3mf() — per-layer, linear scaling, and slot mapping."""

    @pytest.mark.asyncio
    async def test_prefers_live_assignment_when_reassigned_mid_print(self):
        """If tray assignment changed during print, track usage on the new spool."""
        spool_old = _make_spool(spool_id=1, label_weight=1000)
        spool_new = _make_spool(spool_id=2, label_weight=1000)
        archive = _make_archive(archive_id=80)

        live_assignment = _make_assignment(spool_id=2, ams_id=0, tray_id=0)
        started_at = datetime.now(timezone.utc)
        live_assignment.created_at = started_at + timedelta(seconds=5)

        # db: archive, queue_item(None), live assignment lookup, spool_new lookup
        db = _mock_db_sequential([archive, None, live_assignment, spool_new])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=0,
        )

        filament_usage = [{"slot_id": 1, "used_g": 10.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=80,
                status="completed",
                print_name="MidPrintReassign",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                spool_assignments={(0, 0): spool_old.id},
                print_started_at=started_at,
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == spool_new.id

    @pytest.mark.asyncio
    async def test_keeps_snapshot_when_live_assignment_predates_print(self):
        """If live assignment predates print start, preserve snapshot spool mapping."""
        spool_old = _make_spool(spool_id=1, label_weight=1000)
        archive = _make_archive(archive_id=81)

        live_assignment = _make_assignment(spool_id=2, ams_id=0, tray_id=0)
        started_at = datetime.now(timezone.utc)
        live_assignment.created_at = started_at - timedelta(seconds=5)

        # db: archive, queue_item(None), live assignment lookup, spool_old lookup
        db = _mock_db_sequential([archive, None, live_assignment, spool_old])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=0,
        )

        filament_usage = [{"slot_id": 1, "used_g": 10.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=81,
                status="completed",
                print_name="SnapshotPreserved",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                spool_assignments={(0, 0): spool_old.id},
                print_started_at=started_at,
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == spool_old.id

    @pytest.mark.asyncio
    async def test_linear_fallback_for_partial_print(self):
        """Falls back to linear scaling when gcode layer data unavailable."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1)
        archive = _make_archive(archive_id=10)

        # db: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=50,
            layer_num=25,
            tray_now=0,
        )

        filament_usage = [{"slot_id": 1, "used_g": 20.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=None,  # No layer data available
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=10,
                status="failed",
                print_name="Benchy",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 1
        # 50% of 20g = 10g
        assert results[0]["weight_used"] == 10.0
        # Tray should be marked as handled
        assert (0, 0) in handled_trays

    @pytest.mark.asyncio
    async def test_per_layer_partial_print(self):
        """Failed print at layer N uses gcode cumulative data."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1)
        archive = _make_archive(archive_id=10)

        # db: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=50,
            layer_num=25,
            tray_now=0,
        )

        filament_usage = [{"slot_id": 1, "used_g": 20.0, "type": "PLA", "color": ""}]
        # Per-layer data: at layer 25, filament 0 used 5000mm
        layer_data = {10: {0: 2000.0}, 25: {0: 5000.0}, 50: {0: 10000.0}}
        filament_props = {1: {"density": 1.24, "diameter": 1.75}}
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=layer_data,
            ),
            patch(
                "backend.app.utils.threemf_tools.get_cumulative_usage_at_layer",
                return_value={0: 5000.0},
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_filament_properties_from_3mf",
                return_value=filament_props,
            ),
            patch(
                "backend.app.utils.threemf_tools.mm_to_grams",
                return_value=12.0,  # 5000mm at 1.75mm/1.24g/cm3
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=10,
                status="failed",
                print_name="Benchy",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 1
        # Should use per-layer grams (12.0g), not linear scale (10.0g)
        assert results[0]["weight_used"] == 12.0

    @pytest.mark.asyncio
    async def test_completed_print_uses_full_weight(self):
        """Completed print uses full 3MF weight (scale=1.0)."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1)
        archive = _make_archive(archive_id=10)

        # db: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=0,
        )

        filament_usage = [{"slot_id": 1, "used_g": 20.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=10,
                status="completed",
                print_name="Benchy",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 1
        assert results[0]["weight_used"] == 20.0

    @pytest.mark.asyncio
    async def test_tray_now_override_for_single_filament(self):
        """Single-filament non-queue print uses tray_now instead of slot_id mapping."""
        # Spool 2 is at AMS1-T3 (global_tray_id=7)
        spool = _make_spool(spool_id=2, label_weight=1000)
        assignment = _make_assignment(spool_id=2, ams_id=1, tray_id=3)
        archive = _make_archive(archive_id=10)

        # db: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        # tray_now=7 = (ams_id=1, tray_id=3), the ACTUAL tray used
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=7,
        )

        # 3MF has slot_id=12 (would default-map to ams_id=2, tray_id=3 — WRONG)
        filament_usage = [{"slot_id": 12, "used_g": 10.6, "type": "PLA", "color": "#FF0000"}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=10,
                status="completed",
                print_name="Test",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == 2
        assert results[0]["ams_id"] == 1
        assert results[0]["tray_id"] == 3
        assert results[0]["weight_used"] == 10.6
        assert (1, 3) in handled_trays

    @pytest.mark.asyncio
    async def test_queue_ams_mapping_overrides_default(self):
        """Queue item ams_mapping overrides default slot_id mapping."""
        # Spool at AMS1-T3 (global_tray_id=7)
        spool = _make_spool(spool_id=5, label_weight=1000)
        assignment = _make_assignment(spool_id=5, ams_id=1, tray_id=3)
        archive = _make_archive(archive_id=20)
        # Queue item maps slot 1 → global tray 7 (ams_id=1, tray_id=3)
        queue_item = _make_queue_item(ams_mapping="[7, -1, -1, -1]")

        # db: archive, queue_item, assignment, spool
        db = _mock_db_sequential([archive, queue_item, assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=7,
        )

        filament_usage = [{"slot_id": 1, "used_g": 25.0, "type": "PETG", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=20,
                status="completed",
                print_name="Queue Print",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == 5
        assert results[0]["ams_id"] == 1
        assert results[0]["tray_id"] == 3
        assert results[0]["weight_used"] == 25.0

    @pytest.mark.asyncio
    async def test_multi_filament_uses_queue_mapping(self):
        """Multi-filament queue prints use ams_mapping for each slot."""
        spool_a = _make_spool(spool_id=1, label_weight=1000)
        spool_b = _make_spool(spool_id=2, label_weight=1000)
        assign_a = _make_assignment(spool_id=1, ams_id=0, tray_id=0)
        assign_b = _make_assignment(spool_id=2, ams_id=1, tray_id=2)
        archive = _make_archive(archive_id=30)
        # slot 1 → tray 0 (AMS0-T0), slot 2 → tray 6 (AMS1-T2)
        queue_item = _make_queue_item(ams_mapping="[0, 6]")

        # db: archive, queue_item, assign_a, spool_a, assign_b, spool_b
        db = _mock_db_sequential([archive, queue_item, assign_a, spool_a, assign_b, spool_b])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=6,
        )

        filament_usage = [
            {"slot_id": 1, "used_g": 10.0, "type": "PLA", "color": ""},
            {"slot_id": 2, "used_g": 5.0, "type": "PETG", "color": ""},
        ]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=30,
                status="completed",
                print_name="Multi",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 2
        assert results[0]["spool_id"] == 1
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 0
        assert results[0]["weight_used"] == 10.0
        assert results[1]["spool_id"] == 2
        assert results[1]["ams_id"] == 1
        assert results[1]["tray_id"] == 2
        assert results[1]["weight_used"] == 5.0

    @pytest.mark.asyncio
    async def test_no_tray_now_override_for_multi_filament(self):
        """Multi-filament non-queue prints fall back to default mapping, not tray_now."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=0)
        archive = _make_archive(archive_id=10)

        # db: archive, queue_item(None), assignment, spool (2nd slot has no assignment)
        db = _mock_db_sequential([archive, None, assignment, spool, None])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=4,  # tray_now won't be used
        )

        # Two filament slots with usage
        filament_usage = [
            {"slot_id": 1, "used_g": 10.0, "type": "PLA", "color": ""},
            {"slot_id": 2, "used_g": 5.0, "type": "PETG", "color": ""},
        ]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=10,
                status="completed",
                print_name="Test",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        # Should use default mapping (slot 1 → tray 0, slot 2 → tray 1)
        assert len(results) == 1  # Only slot 1 has assignment
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 0

    @pytest.mark.asyncio
    async def test_stored_ams_mapping_overrides_all(self):
        """Stored ams_mapping from print command takes priority over queue and tray_now."""
        # Spool at AMS2-T1 (global_tray_id=9)
        spool = _make_spool(spool_id=10, label_weight=1000)
        assignment = _make_assignment(spool_id=10, ams_id=2, tray_id=1)
        archive = _make_archive(archive_id=50)

        # db: archive, assignment, spool (no queue lookup when ams_mapping provided)
        db = _mock_db_sequential([archive, assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=0,  # Different from mapped tray — should be ignored
            last_loaded_tray=0,
        )

        filament_usage = [{"slot_id": 2, "used_g": 1.57, "type": "PLA", "color": "#FFFFFF"}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            # ams_mapping: slot 2 (index 1) -> tray 9 (AMS2-T1)
            results = await _track_from_3mf(
                printer_id=1,
                archive_id=50,
                status="completed",
                print_name="Test",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                ams_mapping=[-1, 9],
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == 10
        assert results[0]["ams_id"] == 2
        assert results[0]["tray_id"] == 1
        assert results[0]["weight_used"] == 1.6  # rounded

    @pytest.mark.asyncio
    async def test_last_loaded_tray_fallback(self):
        """Falls back to last_loaded_tray when tray_now_at_start and current tray_now are both 255."""
        # Spool at AMS2-T1 (global_tray_id=9)
        spool = _make_spool(spool_id=11, label_weight=1000)
        assignment = _make_assignment(spool_id=11, ams_id=2, tray_id=1)
        archive = _make_archive(archive_id=60)

        # db: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        # H2D scenario: tray_now=255 at completion, but last_loaded_tray=9
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=255,
            last_loaded_tray=9,
        )

        filament_usage = [{"slot_id": 6, "used_g": 1.52, "type": "PLA", "color": "#7CC4D5"}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=60,
                status="completed",
                print_name="Cube",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                tray_now_at_start=255,  # H2D: 255 at start too
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == 11
        assert results[0]["ams_id"] == 2
        assert results[0]["tray_id"] == 1

    @pytest.mark.asyncio
    async def test_tray_now_at_start_preferred_over_last_loaded(self):
        """tray_now_at_start is used before last_loaded_tray fallback."""
        spool = _make_spool(spool_id=3, label_weight=1000)
        assignment = _make_assignment(spool_id=3, ams_id=1, tray_id=1)
        archive = _make_archive(archive_id=70)

        db = _mock_db_sequential([archive, None, assignment, spool])

        # tray_now_at_start=5 (valid), last_loaded_tray=9 (different) — should use 5
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=50,
            tray_now=255,
            last_loaded_tray=9,
        )

        filament_usage = [{"slot_id": 1, "used_g": 5.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=70,
                status="completed",
                print_name="Test",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                tray_now_at_start=5,  # AMS1-T1
            )

        assert len(results) == 1
        assert results[0]["ams_id"] == 1
        assert results[0]["tray_id"] == 1


class TestTrayChangeSplit:
    """Tests for mid-print tray switch weight splitting in _track_from_3mf()."""

    @pytest.mark.asyncio
    async def test_tray_switch_splits_weight_with_gcode(self):
        """Two-tray runout: weight split using per-layer gcode data."""
        spool_a = _make_spool(spool_id=10, label_weight=1000)
        spool_b = _make_spool(spool_id=20, label_weight=1000)
        assign_a = _make_assignment(spool_id=10, ams_id=0, tray_id=1)
        assign_b = _make_assignment(spool_id=20, ams_id=0, tray_id=0)
        archive = _make_archive(archive_id=100)

        # db: archive, queue_item(None), then for each segment: assignment, spool
        db = _mock_db_sequential([archive, None, assign_a, spool_a, assign_b, spool_b])

        # Tray change log: started on tray 1, switched to tray 0 at layer 60
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=100,
            tray_now=0,
            last_loaded_tray=0,
            total_layers=100,
            tray_change_log=[(1, 0), (0, 60)],
        )

        filament_usage = [{"slot_id": 1, "used_g": 30.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value={30: {0: 3000.0}, 60: {0: 6000.0}, 100: {0: 10000.0}},
            ),
            patch(
                "backend.app.utils.threemf_tools.get_cumulative_usage_at_layer",
                side_effect=lambda data, layer: {0: {0: 0.0, 60: 6000.0, 100: 10000.0}.get(layer, 0.0)},
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_filament_properties_from_3mf",
                return_value={1: {"density": 1.24, "diameter": 1.75}},
            ),
            patch(
                "backend.app.utils.threemf_tools.mm_to_grams",
                side_effect=lambda mm, d, dens: round(mm * 0.003, 1),  # Simple conversion
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=100,
                status="completed",
                print_name="Runout Test",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        # Two results: one per tray segment
        assert len(results) == 2
        # First segment: tray 1 (AMS0-T1), layers 0→60
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 1
        assert results[0]["spool_id"] == 10
        assert results[0]["weight_used"] == 18.0  # 6000mm * 0.003
        # Second segment: tray 0 (AMS0-T0), layers 60→end = 30.0 - 18.0 = 12.0
        assert results[1]["ams_id"] == 0
        assert results[1]["tray_id"] == 0
        assert results[1]["spool_id"] == 20
        assert results[1]["weight_used"] == 12.0
        # Both trays handled
        assert (0, 1) in handled_trays
        assert (0, 0) in handled_trays

    @pytest.mark.asyncio
    async def test_tray_switch_linear_fallback(self):
        """Two-tray runout without per-layer gcode: linear split by layer ratio."""
        spool_a = _make_spool(spool_id=10, label_weight=1000)
        spool_b = _make_spool(spool_id=20, label_weight=1000)
        assign_a = _make_assignment(spool_id=10, ams_id=0, tray_id=2)
        assign_b = _make_assignment(spool_id=20, ams_id=0, tray_id=1)
        archive = _make_archive(archive_id=101)

        db = _mock_db_sequential([archive, None, assign_a, spool_a, assign_b, spool_b])

        # Tray 2 from layer 0, switched to tray 1 at layer 40 (of 100 total)
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=100,
            tray_now=1,
            last_loaded_tray=1,
            total_layers=100,
            tray_change_log=[(2, 0), (1, 40)],
        )

        filament_usage = [{"slot_id": 1, "used_g": 50.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=None,  # No per-layer gcode available
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=101,
                status="completed",
                print_name="Linear Fallback",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 2
        # Linear split: tray 2 for 40/100 layers = 20g
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 2
        assert results[0]["weight_used"] == 20.0
        # Last segment gets remainder: 50 - 20 = 30g
        assert results[1]["ams_id"] == 0
        assert results[1]["tray_id"] == 1
        assert results[1]["weight_used"] == 30.0

    @pytest.mark.asyncio
    async def test_tray_switch_overrides_print_cmd_mapping(self):
        """tray_change_log evidence overrides slot_to_tray captured at print start.

        Regression for #957: when AMS auto-falls-back from an empty spool to a
        same-material sibling, the print_cmd's mapping (which named the
        original tray) is stale by the time the print finishes. Before this
        fix, the splitting branch was gated on ``not slot_to_tray`` so the
        slicer mapping was preferred even when the printer actually fed from
        a different tray — Path 1 credited the original tray with the full
        3MF estimate and Path 2 layered the AMS-fallback delta on top, so
        spool consumption double-counted (e.g. 78 g print credited as 78 g
        + 60 g = 138 g). This test pins the new behavior: when
        tray_change_log has > 1 entries, splitting takes over regardless of
        whether ams_mapping was provided.
        """
        spool_a = _make_spool(spool_id=10, label_weight=1000)
        spool_b = _make_spool(spool_id=20, label_weight=1000)
        assign_a = _make_assignment(spool_id=10, ams_id=0, tray_id=0)
        assign_b = _make_assignment(spool_id=20, ams_id=0, tray_id=1)
        archive = _make_archive(archive_id=200)

        # No queue_item placeholder: passing ams_mapping bypasses the queue lookup
        # at usage_tracker.py:816 (`if not slot_to_tray and archive_id`).
        db = _mock_db_sequential([archive, assign_a, spool_a, assign_b, spool_b])

        # Slicer mapping says slot 1 -> tray 0; printer actually swapped to tray 1 at layer 30
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=100,
            tray_now=1,
            last_loaded_tray=1,
            total_layers=100,
            tray_change_log=[(0, 0), (1, 30)],
        )

        filament_usage = [{"slot_id": 1, "used_g": 78.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=None,  # No per-layer data — exercises linear fallback
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=200,
                status="completed",
                print_name="Runout w/ slicer mapping",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                # ams_mapping captured at print start — slicer told us slot 0 -> tray 0
                # (1-based slot_id=1 -> 0-based slot index 0).
                ams_mapping=[0],
            )

        # Splitting branch ran despite ams_mapping being set: two segments,
        # one per tray, total weight matches the 3MF estimate (no double-count).
        assert len(results) == 2
        total = sum(r["weight_used"] for r in results)
        assert total == pytest.approx(78.0, abs=0.1)
        # Both trays now in handled_trays so Path 2 (remain%-delta) skips them.
        assert (0, 0) in handled_trays
        assert (0, 1) in handled_trays

    @pytest.mark.asyncio
    async def test_no_tray_change_uses_normal_path(self):
        """Single-entry tray_change_log falls through to normal tray_now_at_start logic."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=2)
        archive = _make_archive(archive_id=102)

        db = _mock_db_sequential([archive, None, assignment, spool])

        # Only one entry = no switch, should use normal path
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=100,
            tray_now=2,
            last_loaded_tray=2,
            total_layers=100,
            tray_change_log=[(2, 0)],
        )

        filament_usage = [{"slot_id": 1, "used_g": 15.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=102,
                status="completed",
                print_name="No Switch",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                tray_now_at_start=2,
            )

        # Normal path: single result, full weight
        assert len(results) == 1
        assert results[0]["weight_used"] == 15.0
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 2

    @pytest.mark.asyncio
    async def test_empty_tray_change_log_uses_normal_path(self):
        """Empty tray_change_log (e.g. server restart) falls through to existing logic."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=0)
        archive = _make_archive(archive_id=103)

        db = _mock_db_sequential([archive, None, assignment, spool])

        # Empty log (server restarted mid-print)
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=100,
            tray_now=0,
            last_loaded_tray=0,
            total_layers=100,
            tray_change_log=[],
        )

        filament_usage = [{"slot_id": 1, "used_g": 10.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=103,
                status="completed",
                print_name="Restart Recovery",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                tray_now_at_start=0,
            )

        assert len(results) == 1
        assert results[0]["weight_used"] == 10.0

    @pytest.mark.asyncio
    async def test_tray_switch_segment_no_spool(self):
        """Segment with no spool assignment is skipped; other segments still tracked."""
        spool_b = _make_spool(spool_id=20, label_weight=1000)
        assign_b = _make_assignment(spool_id=20, ams_id=0, tray_id=3)
        archive = _make_archive(archive_id=104)

        # db: archive, queue_item(None), 1st segment: no assignment, 2nd segment: assignment, spool
        db = _mock_db_sequential([archive, None, None, assign_b, spool_b])

        # Tray 5 (no spool) from layer 0, switched to tray 3 at layer 50
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=100,
            tray_now=3,
            last_loaded_tray=3,
            total_layers=100,
            tray_change_log=[(5, 0), (3, 50)],
        )

        filament_usage = [{"slot_id": 1, "used_g": 40.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=None,  # No per-layer data
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=104,
                status="completed",
                print_name="Missing Spool",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        # Only the second segment (tray 3) tracked; first segment (tray 5) skipped
        assert len(results) == 1
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 3
        assert results[0]["spool_id"] == 20

    @pytest.mark.asyncio
    async def test_tray_switch_three_segments(self):
        """Three-segment switch (rare): A→B→C split by linear fallback."""
        spool_a = _make_spool(spool_id=1, label_weight=1000)
        spool_b = _make_spool(spool_id=2, label_weight=1000)
        spool_c = _make_spool(spool_id=3, label_weight=1000)
        assign_a = _make_assignment(spool_id=1, ams_id=0, tray_id=0)
        assign_b = _make_assignment(spool_id=2, ams_id=0, tray_id=1)
        assign_c = _make_assignment(spool_id=3, ams_id=0, tray_id=2)
        archive = _make_archive(archive_id=105)

        db = _mock_db_sequential(
            [
                archive,
                None,
                assign_a,
                spool_a,
                assign_b,
                spool_b,
                assign_c,
                spool_c,
            ]
        )

        # 3 segments: tray 0 (0-30), tray 1 (30-70), tray 2 (70-end)
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=100,
            tray_now=2,
            last_loaded_tray=2,
            total_layers=100,
            tray_change_log=[(0, 0), (1, 30), (2, 70)],
        )

        filament_usage = [{"slot_id": 1, "used_g": 100.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=None,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=105,
                status="completed",
                print_name="Triple Switch",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 3
        # Tray 0: 30/100 * 100g = 30g
        assert results[0]["weight_used"] == 30.0
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 0
        # Tray 1: 40/100 * 100g = 40g
        assert results[1]["weight_used"] == 40.0
        assert results[1]["ams_id"] == 0
        assert results[1]["tray_id"] == 1
        # Tray 2: remainder = 100 - 30 - 40 = 30g
        assert results[2]["weight_used"] == 30.0
        assert results[2]["ams_id"] == 0
        assert results[2]["tray_id"] == 2

    @pytest.mark.asyncio
    async def test_tray_switch_uses_last_layer_num_when_total_layers_reset(self):
        """#1771 regression: P1S firmware resets `total_layer_num` to 0 at print
        end; without the cascade the linear fallback collapsed to `0.0` per
        non-last segment and dumped the whole print onto the last spool. With
        the fix, `last_layer_num` (the print's last-valid layer captured before
        the firmware reset) is the substitute denominator.

        Reporter's exact shape: print needed ~260 g, started on a 180 g spool,
        AMS Backup switched at ~70% through, second spool finished the print.
        Before fix: spool 1 → 0 g, spool 2 → 260 g (the bug).
        After fix:  spool 1 → 180 g, spool 2 → 80 g (correct).
        """
        spool_a = _make_spool(spool_id=10, label_weight=1000)
        spool_b = _make_spool(spool_id=20, label_weight=1000)
        assign_a = _make_assignment(spool_id=10, ams_id=0, tray_id=0)
        assign_b = _make_assignment(spool_id=20, ams_id=0, tray_id=1)
        archive = _make_archive(archive_id=171)

        db = _mock_db_sequential([archive, None, assign_a, spool_a, assign_b, spool_b])

        # Firmware reset: state.total_layers is 0 by the time usage_tracker runs.
        # last_layer_num threaded in from on_print_complete is the survival value.
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=0,  # also reset
            tray_now=1,
            last_loaded_tray=1,
            total_layers=0,  # the bug trigger
            tray_change_log=[(0, 0), (1, 180)],  # switched at layer 180 of 260
        )

        filament_usage = [{"slot_id": 1, "used_g": 260.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=None,  # No per-layer 3MF data — force linear fallback path
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=171,
                status="completed",
                print_name="#1771 repro",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                last_layer_num=260,  # survives the firmware reset of total_layer_num
            )

        # Both segments must be attributed correctly.
        assert len(results) == 2
        # Segment 1: tray 0, layers 0-180 of 260 → 260 * 180/260 = 180.0 g
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 0
        assert results[0]["weight_used"] == 180.0
        # Segment 2: tray 1, remainder = 260 - 180 = 80.0 g
        assert results[1]["ams_id"] == 0
        assert results[1]["tray_id"] == 1
        assert results[1]["weight_used"] == 80.0

    @pytest.mark.asyncio
    async def test_tray_switch_equal_split_when_no_layer_info_at_all(self):
        """Defensive fence: when neither `state.total_layers` nor `last_layer_num`
        survives (older firmware / edge case), equal-split across segments is the
        last-resort fallback. Still wrong but BOUNDED — the original bug dumped
        the whole print weight onto the last segment, which was strictly worse.
        """
        spool_a = _make_spool(spool_id=10, label_weight=1000)
        spool_b = _make_spool(spool_id=20, label_weight=1000)
        assign_a = _make_assignment(spool_id=10, ams_id=0, tray_id=0)
        assign_b = _make_assignment(spool_id=20, ams_id=0, tray_id=1)
        archive = _make_archive(archive_id=172)

        db = _mock_db_sequential([archive, None, assign_a, spool_a, assign_b, spool_b])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            progress=100,
            layer_num=0,
            tray_now=1,
            last_loaded_tray=1,
            total_layers=0,  # neither source available
            tray_change_log=[(0, 0), (1, 50)],
        )

        filament_usage = [{"slot_id": 1, "used_g": 60.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch(
                "backend.app.utils.threemf_tools.extract_layer_filament_usage_from_3mf",
                return_value=None,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=172,
                status="completed",
                print_name="no layer info",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                last_layer_num=0,  # also unavailable
            )

        # 2 segments, equal split: 60g / 2 = 30g each. Last segment uses the
        # `is_last` remainder branch so it stays at 30.0 too.
        assert len(results) == 2
        assert results[0]["weight_used"] == 30.0
        assert results[1]["weight_used"] == 30.0


class TestDecodeMqttMapping:
    """Tests for _decode_mqtt_mapping() — snow-encoded MQTT mapping to global tray IDs."""

    def test_none_input(self):
        assert _decode_mqtt_mapping(None) is None

    def test_empty_list(self):
        assert _decode_mqtt_mapping([]) is None

    def test_all_unmapped(self):
        """All 65535 values → None (no valid mappings)."""
        assert _decode_mqtt_mapping([65535, 65535, 65535]) is None

    def test_single_ams_slots(self):
        """AMS 0 slots: snow values 0-3 → global tray IDs 0-3."""
        assert _decode_mqtt_mapping([0, 1, 2, 3]) == [0, 1, 2, 3]

    def test_multi_ams_slots(self):
        """AMS 1 (hw_id=1): snow 256=AMS1-T0, 257=AMS1-T1 → global 4, 5."""
        assert _decode_mqtt_mapping([256, 257]) == [4, 5]

    def test_ams_ht_slot(self):
        """AMS-HT (hw_id=128): snow 32768 → global 128."""
        assert _decode_mqtt_mapping([32768]) == [128]

    def test_external_spool(self):
        """External spool: ams_hw_id=254, slot=0 → global 254."""
        # snow = 254 * 256 + 0 = 65024
        assert _decode_mqtt_mapping([65024]) == [254]

    def test_mixed_with_unmapped(self):
        """Mix of valid and unmapped (65535) values."""
        result = _decode_mqtt_mapping([1, 65535, 0])
        assert result == [1, -1, 0]

    def test_h2c_real_mapping(self):
        """Real H2C mapping from MQTT logs: [1, 0, 65535*4, 32768]."""
        mapping = [1, 0, 65535, 65535, 65535, 65535, 32768]
        result = _decode_mqtt_mapping(mapping)
        assert result == [1, 0, -1, -1, -1, -1, 128]

    def test_non_int_values_treated_as_unmapped(self):
        """Non-integer values in the mapping are treated as unmapped."""
        assert _decode_mqtt_mapping(["foo", 0]) == [-1, 0]


class TestMatchSlotsByColor:
    """Tests for _match_slots_by_color() — color-based filament slot to AMS tray matching."""

    def _ams(self, trays):
        """Build AMS data from list of (ams_id, tray_id, color_hex, tray_type) tuples."""
        units: dict[int, list] = {}
        for ams_id, tray_id, color, tray_type in trays:
            units.setdefault(ams_id, []).append({"id": tray_id, "tray_color": color, "tray_type": tray_type})
        return [{"id": aid, "tray": t} for aid, t in units.items()]

    def _usage(self, slots):
        """Build filament_usage from list of (slot_id, color_hex) tuples."""
        return [{"slot_id": sid, "used_g": 10.0, "type": "PLA", "color": color} for sid, color in slots]

    def test_none_inputs(self):
        assert _match_slots_by_color(None, None) is None
        assert _match_slots_by_color([], None) is None
        assert _match_slots_by_color(None, {"ams": []}) is None

    def test_empty_ams(self):
        usage = self._usage([(1, "#FF0000")])
        assert _match_slots_by_color(usage, {"ams": []}) is None

    def test_single_slot_single_tray(self):
        """One 3MF slot matches one AMS tray by color."""
        ams = self._ams([(0, 0, "FF0000FF", "PLA")])
        usage = self._usage([(1, "#FF0000")])
        assert _match_slots_by_color(usage, {"ams": ams}) == [0]

    def test_a1_mini_three_colors(self):
        """A1 Mini: 3 slots match 3 distinct AMS trays."""
        ams = self._ams(
            [
                (0, 0, "FF0000FF", "PLA"),  # Red
                (0, 1, "00FF00FF", "PLA"),  # Green
                (0, 2, "0000FFFF", "PLA"),  # Blue
            ]
        )
        usage = self._usage([(1, "#FF0000"), (2, "#00FF00"), (3, "#0000FF")])
        assert _match_slots_by_color(usage, {"ams": ams}) == [0, 1, 2]

    def test_dual_ams_p2s_like(self):
        """P2S with dual AMS: slots from second AMS unit."""
        ams = self._ams(
            [
                (0, 0, "AAAAAAFF", "PLA"),
                (0, 1, "BBBBBBFF", "PLA"),
                (1, 0, "CC0000FF", "PETG"),  # global_id=4
                (1, 1, "00CC00FF", "PETG"),  # global_id=5
            ]
        )
        usage = self._usage([(1, "#CC0000"), (2, "#00CC00")])
        assert _match_slots_by_color(usage, {"ams": ams}) == [4, 5]

    def test_ams_ht_global_id(self):
        """AMS-HT (ams_id >= 128) uses raw ams_id as global tray ID."""
        ams = self._ams(
            [
                (0, 0, "FF0000FF", "PLA"),
                (128, 0, "0000FFFF", "PLA"),  # AMS-HT → global_id=128
            ]
        )
        usage = self._usage([(1, "#FF0000"), (2, "#0000FF")])
        assert _match_slots_by_color(usage, {"ams": ams}) == [0, 128]

    def test_ambiguous_same_color_returns_none(self):
        """Two trays with the same color → ambiguous → None."""
        ams = self._ams(
            [
                (0, 0, "FF0000FF", "PLA"),
                (0, 1, "FF0000FF", "PLA"),  # Same red
            ]
        )
        usage = self._usage([(1, "#FF0000")])
        assert _match_slots_by_color(usage, {"ams": ams}) is None

    def test_no_matching_color_returns_none(self):
        """3MF slot color not found in any AMS tray → None."""
        ams = self._ams([(0, 0, "00FF00FF", "PLA")])
        usage = self._usage([(1, "#FF0000")])  # Red, but AMS has green
        assert _match_slots_by_color(usage, {"ams": ams}) is None

    def test_color_normalization_strips_alpha(self):
        """AMS colors (RRGGBBAA) and 3MF colors (#RRGGBB) match after normalization."""
        ams = self._ams([(0, 0, "AABBCC80", "PLA")])  # 8-char with alpha
        usage = self._usage([(1, "#AABBCC")])  # 6-char with #
        assert _match_slots_by_color(usage, {"ams": ams}) == [0]

    def test_case_insensitive(self):
        """Color matching is case-insensitive."""
        ams = self._ams([(0, 0, "aaBBccFF", "PLA")])
        usage = self._usage([(1, "#AAbbCC")])
        assert _match_slots_by_color(usage, {"ams": ams}) == [0]

    def test_empty_tray_color_skipped(self):
        """Trays with empty color are skipped (not matched)."""
        ams = self._ams(
            [
                (0, 0, "", "PLA"),
                (0, 1, "FF0000FF", "PLA"),
            ]
        )
        usage = self._usage([(1, "#FF0000")])
        assert _match_slots_by_color(usage, {"ams": ams}) == [1]

    def test_empty_tray_type_skipped(self):
        """Trays with empty tray_type are skipped (unloaded slot)."""
        ams = self._ams(
            [
                (0, 0, "FF0000FF", ""),  # Empty slot
                (0, 1, "FF0000FF", "PLA"),  # Loaded slot
            ]
        )
        usage = self._usage([(1, "#FF0000")])
        assert _match_slots_by_color(usage, {"ams": ams}) == [1]

    def test_short_slot_color_returns_none(self):
        """3MF slot with color < 6 chars → can't match → None."""
        ams = self._ams([(0, 0, "FF0000FF", "PLA")])
        usage = [{"slot_id": 1, "used_g": 10.0, "type": "PLA", "color": "#FFF"}]
        assert _match_slots_by_color(usage, {"ams": ams}) is None

    def test_slot_id_zero_skipped(self):
        """Slots with slot_id=0 are skipped."""
        ams = self._ams([(0, 0, "FF0000FF", "PLA")])
        usage = [{"slot_id": 0, "used_g": 10.0, "type": "PLA", "color": "#FF0000"}]
        assert _match_slots_by_color(usage, {"ams": ams}) is None

    def test_ams_data_as_list(self):
        """Handles ams_raw as a plain list (some printer models)."""
        ams_list = [{"id": 0, "tray": [{"id": 0, "tray_color": "FF0000FF", "tray_type": "PLA"}]}]
        usage = self._usage([(1, "#FF0000")])
        assert _match_slots_by_color(usage, ams_list) == [0]

    def test_same_color_two_trays_disambiguated_by_usage(self):
        """Two trays same color, two slots same color → unique assignment via used_trays tracking."""
        ams = self._ams(
            [
                (0, 0, "FF0000FF", "PLA"),
                (0, 1, "FF0000FF", "PLA"),
            ]
        )
        # Two slots both wanting red — first gets tray 0, second gets tray 1? No.
        # When first slot takes the only available, second has 1 left → should work
        usage = self._usage([(1, "#FF0000"), (2, "#FF0000")])
        # First slot: candidates=[0,1], available=[0,1], len!=1 → None
        assert _match_slots_by_color(usage, {"ams": ams}) is None

    def test_dict_wrapper_with_ams_key(self):
        """Standard dict format with 'ams' key."""
        ams_data = {"ams": [{"id": 0, "tray": [{"id": 0, "tray_color": "00FF00FF", "tray_type": "PLA"}]}]}
        usage = self._usage([(1, "#00FF00")])
        assert _match_slots_by_color(usage, ams_data) == [0]


class TestMqttMappingIntegration:
    """Integration tests: MQTT mapping field used in _track_from_3mf."""

    @pytest.mark.asyncio
    async def test_h2c_multi_filament_uses_mqtt_mapping(self):
        """H2C: 3 filaments resolved via MQTT mapping field (no ams_mapping, no queue)."""
        # AMS0-T1 (White PLA), AMS0-T0 (Black PLA), AMS128-T0 (Red PLA)
        spool_white = _make_spool(spool_id=1, label_weight=1000)
        spool_black = _make_spool(spool_id=2, label_weight=1000)
        spool_red = _make_spool(spool_id=3, label_weight=1000)
        assign_white = _make_assignment(spool_id=1, ams_id=0, tray_id=1)
        assign_black = _make_assignment(spool_id=2, ams_id=0, tray_id=0)
        assign_red = _make_assignment(spool_id=3, ams_id=128, tray_id=0)
        archive = _make_archive(archive_id=12)

        # db: archive, then 3 pairs of (assignment, spool)
        # No queue lookup because MQTT mapping is found first
        db = _mock_db_sequential(
            [
                archive,
                assign_white,
                spool_white,
                assign_black,
                spool_black,
                assign_red,
                spool_red,
            ]
        )

        # MQTT mapping: slot0→AMS0-T1(1), slot1→AMS0-T0(0), slots2-5→unmapped, slot6→AMS128-T0(32768)
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"mapping": [1, 0, 65535, 65535, 65535, 65535, 32768]},
            progress=100,
            layer_num=50,
            tray_now=255,
        )

        # 3MF slots 1, 2, 7 (1-based) → indices 0, 1, 6 in mapping
        filament_usage = [
            {"slot_id": 1, "used_g": 21.16, "type": "PLA", "color": "#FFFFFF"},
            {"slot_id": 2, "used_g": 24.22, "type": "PLA", "color": "#000000"},
            {"slot_id": 7, "used_g": 18.47, "type": "PLA", "color": "#F72323"},
        ]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=12,
                status="completed",
                print_name="Cube + Cube + Cube",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 3

        # slot_id=1 → mapping[0]=1 → AMS0-T1 (White PLA)
        assert results[0]["spool_id"] == 1
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 1
        assert results[0]["weight_used"] == 21.2

        # slot_id=2 → mapping[1]=0 → AMS0-T0 (Black PLA)
        assert results[1]["spool_id"] == 2
        assert results[1]["ams_id"] == 0
        assert results[1]["tray_id"] == 0
        assert results[1]["weight_used"] == 24.2

        # slot_id=7 → mapping[6]=32768 → AMS128-T0 (Red PLA)
        assert results[2]["spool_id"] == 3
        assert results[2]["ams_id"] == 128
        assert results[2]["tray_id"] == 0
        assert results[2]["weight_used"] == 18.5

    @pytest.mark.asyncio
    async def test_print_cmd_mapping_takes_priority_over_mqtt(self):
        """ams_mapping from print command is used even when MQTT mapping exists."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=2)
        archive = _make_archive(archive_id=10)

        # db: archive, assignment, spool (no queue lookup when ams_mapping provided)
        db = _mock_db_sequential([archive, assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"mapping": [0, 65535]},  # MQTT says slot 0 → AMS0-T0
            progress=100,
            layer_num=50,
            tray_now=255,
        )

        filament_usage = [{"slot_id": 1, "used_g": 10.0, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=10,
                status="completed",
                print_name="Test",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
                ams_mapping=[2],  # Print cmd says slot 0 → AMS0-T2 (overrides MQTT)
            )

        assert len(results) == 1
        assert results[0]["ams_id"] == 0
        assert results[0]["tray_id"] == 2  # From print_cmd mapping, not MQTT


class TestPositionBasedFallbackEmptyAmsSlot:
    """Position-based mapping fallback (#1607): when no explicit mapping is
    available, the slicer's Nth filament must map to the Nth *loaded* AMS tray
    (skipping empty slots), not the Nth physical slot position. BambuStudio /
    OrcaSlicer compact their filament-assignment UI by hiding unloaded AMS
    slots, so the 3MF slot list is dense even when the AMS itself has gaps."""

    @pytest.mark.asyncio
    async def test_external_routed_correctly_when_ams_has_empty_middle_slot(self):
        """Reporter's scenario: AMS trays 0-2 loaded, tray 3 empty, external
        loaded. Slicer emits 4 filaments — slot 4 = external. Without the fix
        the position-based fallback maps slot 4 to the empty AMS tray 3
        (since `available_trays = [0, 1, 2, 3, 254]`) and external usage is
        silently dropped because no spool is assigned to AMS0-T3.
        After the fix, empty AMS slots are filtered (tray_type is empty) so
        `available_trays = [0, 1, 2, 254]` and slot 4 correctly resolves to
        the external (global tray 254 → AMS255-T0)."""
        # Spool fed via external (vt_tray 254 → AMS255-T0)
        spool = _make_spool(spool_id=42, label_weight=1000)
        assignment = _make_assignment(spool_id=42, ams_id=255, tray_id=0)
        archive = _make_archive(archive_id=70)

        # db: archive, queue_item(None), assignment, spool
        db = _mock_db_sequential([archive, None, assignment, spool])

        # AMS reports 4 physical tray slots but slot 3 has no spool (empty
        # tray_type); external spool is loaded in vt_tray.
        # No `mapping` field on the state — forces fallback through path 5.
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={
                "ams": [
                    {
                        "id": 0,
                        "tray": [
                            {"id": 0, "tray_type": "PLA"},
                            {"id": 1, "tray_type": "PETG"},
                            {"id": 2, "tray_type": "ABS"},
                            {"id": 3, "tray_type": ""},  # empty slot
                        ],
                    }
                ],
                "vt_tray": [{"id": 254, "tray_type": "PLA"}],
            },
            progress=100,
            layer_num=50,
            tray_now=254,
            tray_change_log=[],
        )

        # 3MF has 4 dense filament slots — slot 4 is the external. Only slot 4
        # has weight (other slots came from AMS spools handled separately).
        filament_usage = [{"slot_id": 4, "used_g": 12.3, "type": "PLA", "color": "#00AABB"}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=70,
                status="completed",
                print_name="External + AMS print",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 1
        # The external spool was charged, NOT the empty AMS slot.
        assert results[0]["spool_id"] == 42
        assert results[0]["ams_id"] == 255
        assert results[0]["tray_id"] == 0
        assert results[0]["weight_used"] == 12.3
        assert (255, 0) in handled_trays
        # Critical assertion: AMS0-T3 (the empty slot) was NOT charged.
        assert (0, 3) not in handled_trays

    @pytest.mark.asyncio
    async def test_dense_ams_unchanged_no_empty_slots(self):
        """Sanity check: when every AMS slot is loaded, the position-based
        fallback still works for the slicer's external = last slot case."""
        spool = _make_spool(spool_id=99, label_weight=1000)
        assignment = _make_assignment(spool_id=99, ams_id=255, tray_id=0)
        archive = _make_archive(archive_id=71)

        db = _mock_db_sequential([archive, None, assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={
                "ams": [
                    {
                        "id": 0,
                        "tray": [
                            {"id": 0, "tray_type": "PLA"},
                            {"id": 1, "tray_type": "PETG"},
                            {"id": 2, "tray_type": "ABS"},
                            {"id": 3, "tray_type": "TPU"},
                        ],
                    }
                ],
                "vt_tray": [{"id": 254, "tray_type": "PLA"}],
            },
            progress=100,
            layer_num=50,
            tray_now=254,
            tray_change_log=[],
        )

        # 5 filaments, slot 5 = external. available_trays = [0,1,2,3,254] →
        # slot_id=5 → available_trays[4] = 254.
        filament_usage = [{"slot_id": 5, "used_g": 7.5, "type": "PLA", "color": ""}]
        handled_trays: set[tuple[int, int]] = set()

        with (
            patch("backend.app.core.config.settings") as mock_settings,
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True
            mock_settings.base_dir.__truediv__ = MagicMock(return_value=mock_path)

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=71,
                status="completed",
                print_name="Dense AMS + external",
                handled_trays=handled_trays,
                printer_manager=printer_manager,
                db=db,
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == 99
        assert results[0]["ams_id"] == 255
        assert results[0]["tray_id"] == 0


class TestNotificationVariables:
    """Tests for filament_details formatting in notifications."""

    def test_filament_details_single_slot(self):
        """Single slot produces 'PLA: 15.2g' format."""
        slots = [{"type": "PLA", "used_g": 15.2, "slot_id": 1, "color": "#FF0000"}]
        parts = []
        for slot in slots:
            ftype = slot.get("type", "Unknown") or "Unknown"
            used = slot.get("used_g", 0)
            parts.append(f"{ftype}: {used:.1f}g")
        result = " | ".join(parts)
        assert result == "PLA: 15.2g"

    def test_filament_details_multi_slot(self):
        """Multiple slots produce 'PLA: 10.0g | PETG: 5.0g' format."""
        slots = [
            {"type": "PLA", "used_g": 10.0, "slot_id": 1, "color": ""},
            {"type": "PETG", "used_g": 5.0, "slot_id": 2, "color": ""},
        ]
        parts = []
        for slot in slots:
            ftype = slot.get("type", "Unknown") or "Unknown"
            used = slot.get("used_g", 0)
            parts.append(f"{ftype}: {used:.1f}g")
        result = " | ".join(parts)
        assert result == "PLA: 10.0g | PETG: 5.0g"

    def test_filament_details_empty_type(self):
        """Empty type defaults to 'Unknown'."""
        slots = [{"type": "", "used_g": 5.0, "slot_id": 1, "color": ""}]
        parts = []
        for slot in slots:
            ftype = slot.get("type", "Unknown") or "Unknown"
            used = slot.get("used_g", 0)
            parts.append(f"{ftype}: {used:.1f}g")
        result = " | ".join(parts)
        assert result == "Unknown: 5.0g"

    def test_filament_grams_scaled_for_partial(self):
        """filament_grams is scaled by progress for partial prints."""
        filament_used_grams = 20.0
        progress = 50
        scale = max(0.0, min(progress / 100.0, 1.0))
        scaled = round(filament_used_grams * scale, 1)
        assert scaled == 10.0

    def test_filament_grams_zero_progress(self):
        """Progress=0 at cancellation gives 0.0g."""
        filament_used_grams = 20.0
        progress = 0
        scale = max(0.0, min(progress / 100.0, 1.0))
        scaled = round(filament_used_grams * scale, 1)
        assert scaled == 0.0

    def test_slot_scaling_for_partial(self):
        """Per-slot usage is scaled linearly for partial prints."""
        slots = [
            {"type": "PLA", "used_g": 20.0, "slot_id": 1, "color": ""},
            {"type": "PETG", "used_g": 10.0, "slot_id": 2, "color": ""},
        ]
        progress = 30
        scale = max(0.0, min(progress / 100.0, 1.0))
        scaled_slots = [{**s, "used_g": round(s["used_g"] * scale, 1)} for s in slots]
        assert scaled_slots[0]["used_g"] == 6.0
        assert scaled_slots[1]["used_g"] == 3.0


class TestOnPrintStartAmsMapping:
    """Tests for ams_mapping capture in on_print_start()."""

    @pytest.fixture(autouse=True)
    def _clear_sessions(self):
        _active_sessions.clear()
        yield
        _active_sessions.clear()

    @pytest.mark.asyncio
    async def test_captures_ams_mapping_from_data(self):
        """on_print_start captures ams_mapping from the data dict into the session."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 80}]}]},
            tray_now=0,
        )

        await on_print_start(1, {"subtask_name": "Test", "ams_mapping": [3, -1, -1, 2]}, printer_manager)

        assert _active_sessions[1].ams_mapping == [3, -1, -1, 2]

    @pytest.mark.asyncio
    async def test_ams_mapping_none_when_not_in_data(self):
        """Session ams_mapping is None when data dict has no ams_mapping."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 80}]}]},
            tray_now=0,
        )

        await on_print_start(1, {"subtask_name": "Test"}, printer_manager)

        assert _active_sessions[1].ams_mapping is None

    @pytest.mark.asyncio
    async def test_captures_queue_plate_id(self):
        """on_print_start records the queue item's plate_id onto the session (#1697)."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 80}]}]},
            tray_now=0,
        )

        queue_item = _make_queue_item(plate_id=2)
        # on_print_start now executes: SpoolAssignment lookup, then PrintQueueItem lookup.
        db = AsyncMock()
        assignment_result = MagicMock()
        assignment_result.scalars.return_value.all.return_value = []
        queue_result = MagicMock()
        queue_result.scalars.return_value.first.return_value = queue_item
        db.execute = AsyncMock(side_effect=[assignment_result, queue_result])

        await on_print_start(1, {"subtask_name": "Test"}, printer_manager, db=db)

        assert _active_sessions[1].plate_id == 2

    @pytest.mark.asyncio
    async def test_plate_id_none_when_no_queue_item(self):
        """Direct/library prints with no queue item leave session.plate_id = None."""
        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": [{"id": 0, "remain": 80}]}]},
            tray_now=0,
        )

        db = AsyncMock()
        assignment_result = MagicMock()
        assignment_result.scalars.return_value.all.return_value = []
        queue_result = MagicMock()
        queue_result.scalars.return_value.first.return_value = None
        db.execute = AsyncMock(side_effect=[assignment_result, queue_result])

        await on_print_start(1, {"subtask_name": "Test"}, printer_manager, db=db)

        assert _active_sessions[1].plate_id is None


class TestFindThreemfByFilename:
    """Tests for _find_3mf_by_filename() — library/archive search without archive_id."""

    @pytest.mark.asyncio
    async def test_finds_library_file(self):
        """Finds a 3MF from library files matching filename."""
        from pathlib import Path
        from unittest.mock import MagicMock

        lib_file = MagicMock()
        lib_file.file_path = "library/BMCU-BADGE.3mf"

        mock_result = MagicMock()
        mock_result.scalars.return_value.all.return_value = [lib_file]

        db = AsyncMock()
        db.execute = AsyncMock(return_value=mock_result)

        base_dir = MagicMock(spec=Path)
        candidate = MagicMock(spec=Path)
        candidate.exists.return_value = True
        candidate.suffix = ".3mf"
        base_dir.__truediv__ = MagicMock(return_value=candidate)

        result = await _find_3mf_by_filename(1, "BMCU-BADGE.3mf", db, base_dir)

        assert result == candidate

    @pytest.mark.asyncio
    async def test_returns_none_for_empty_filename(self):
        """Returns None when filename is empty or just extensions."""
        db = AsyncMock()
        base_dir = MagicMock()

        result = await _find_3mf_by_filename(1, ".3mf", db, base_dir)
        assert result is None

        result = await _find_3mf_by_filename(1, "", db, base_dir)
        assert result is None

    @pytest.mark.asyncio
    async def test_falls_through_to_archive_search(self):
        """Falls back to previous archives when library search returns no results."""
        from pathlib import Path

        # Library returns nothing
        empty_result = MagicMock()
        empty_result.scalars.return_value.all.return_value = []

        # Archive returns a match
        archive = MagicMock()
        archive.id = 35
        archive.file_path = "archives/35/BMCU-BADGE.3mf"
        archive_result = MagicMock()
        archive_result.scalars.return_value.all.return_value = [archive]

        db = AsyncMock()
        db.execute = AsyncMock(side_effect=[empty_result, archive_result])

        base_dir = MagicMock(spec=Path)
        candidate = MagicMock(spec=Path)
        candidate.exists.return_value = True
        candidate.suffix = ".3mf"
        base_dir.__truediv__ = MagicMock(return_value=candidate)

        result = await _find_3mf_by_filename(1, "BMCU-BADGE.3mf", db, base_dir)

        assert result == candidate
        assert db.execute.call_count == 2

    @pytest.mark.asyncio
    async def test_returns_none_when_nothing_found(self):
        """Returns None when neither library nor archives have a matching 3MF."""
        empty_result = MagicMock()
        empty_result.scalars.return_value.all.return_value = []

        db = AsyncMock()
        db.execute = AsyncMock(return_value=empty_result)

        base_dir = MagicMock()

        result = await _find_3mf_by_filename(1, "nonexistent.3mf", db, base_dir)

        assert result is None

    @pytest.mark.asyncio
    async def test_strips_path_and_extensions(self):
        """Correctly strips path components and extensions for search."""
        empty_result = MagicMock()
        empty_result.scalars.return_value.all.return_value = []

        db = AsyncMock()
        db.execute = AsyncMock(return_value=empty_result)

        base_dir = MagicMock()

        # Should search for "BMCU-BADGE" base name even with path and .gcode.3mf
        await _find_3mf_by_filename(1, "/sdcard/BMCU-BADGE.gcode.3mf", db, base_dir)

        # Verify the execute was called (search was attempted with stripped name)
        assert db.execute.call_count == 2  # library + archive search


class TestTrackFrom3mfWithPreresolvedPath:
    """Tests for _track_from_3mf() with threemf_path (no archive needed)."""

    @pytest.mark.asyncio
    async def test_uses_preresolved_path_without_archive(self):
        """When threemf_path is provided with archive_id=None, uses the path directly."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=3)

        # DB: 1st call = assignment lookup (live), 2nd = spool lookup
        db = _mock_db_sequential([assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": []}]},
            tray_now=255,
            last_loaded_tray=3,
            tray_change_log=[],
        )

        filament_usage = [{"slot_id": 1, "used_g": 5.0, "type": "PETG", "color": "#FFFFFF"}]

        with (
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch("backend.app.core.config.settings") as mock_settings,
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True

            results = await _track_from_3mf(
                printer_id=1,
                archive_id=None,
                status="completed",
                print_name="BMCU-BADGE",
                handled_trays=set(),
                printer_manager=printer_manager,
                db=db,
                ams_mapping=[3, -1, -1, -1],
                threemf_path=mock_path,
            )

        assert len(results) == 1
        assert results[0]["spool_id"] == 1
        assert results[0]["weight_used"] == 5.0

    @pytest.mark.asyncio
    async def test_skips_queue_lookup_without_archive_id(self):
        """When archive_id is None, queue item lookup is skipped."""
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=0)

        db = _mock_db_sequential([assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": []}]},
            tray_now=0,
            last_loaded_tray=0,
            tray_change_log=[],
        )

        filament_usage = [{"slot_id": 1, "used_g": 2.0, "type": "PLA", "color": "#FF0000"}]

        with (
            patch(
                "backend.app.utils.threemf_tools.extract_filament_usage_from_3mf",
                return_value=filament_usage,
            ),
            patch("backend.app.core.config.settings") as mock_settings,
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True

            # Should NOT fail even though there's no archive_id for queue lookup
            results = await _track_from_3mf(
                printer_id=1,
                archive_id=None,
                status="completed",
                print_name="Test",
                handled_trays=set(),
                printer_manager=printer_manager,
                db=db,
                tray_now_at_start=0,
                threemf_path=mock_path,
            )

        assert len(results) == 1
        assert results[0]["weight_used"] == 2.0


class TestTrackFrom3mfPlateId:
    """plate_id must propagate from PrintSession through _track_from_3mf to the
    3MF parser, so multi-plate files dispatched for one plate only count that
    plate's filament (#1697)."""

    @pytest.mark.asyncio
    async def test_passes_plate_id_to_3mf_extract(self):
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=0)

        db = _mock_db_sequential([assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": []}]},
            tray_now=0,
            last_loaded_tray=0,
            tray_change_log=[],
        )

        extract_mock = MagicMock(return_value=[{"slot_id": 1, "used_g": 190.0, "type": "PETG", "color": "#888888"}])

        with (
            patch("backend.app.utils.threemf_tools.extract_filament_usage_from_3mf", extract_mock),
            patch("backend.app.core.config.settings") as mock_settings,
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True

            await _track_from_3mf(
                printer_id=1,
                archive_id=None,
                status="completed",
                print_name="GridfinityLid",
                handled_trays=set(),
                printer_manager=printer_manager,
                db=db,
                tray_now_at_start=0,
                threemf_path=mock_path,
                plate_id=2,
            )

        # plate_id=2 passed positionally as second arg
        assert extract_mock.call_count == 1
        assert extract_mock.call_args.args[1] == 2

    @pytest.mark.asyncio
    async def test_plate_id_none_for_non_queue_print(self):
        spool = _make_spool(spool_id=1, label_weight=1000)
        assignment = _make_assignment(spool_id=1, ams_id=0, tray_id=0)

        db = _mock_db_sequential([assignment, spool])

        printer_manager = MagicMock()
        printer_manager.get_status.return_value = SimpleNamespace(
            raw_data={"ams": [{"id": 0, "tray": []}]},
            tray_now=0,
            last_loaded_tray=0,
            tray_change_log=[],
        )

        extract_mock = MagicMock(return_value=[{"slot_id": 1, "used_g": 5.0, "type": "PLA", "color": "#FF0000"}])

        with (
            patch("backend.app.utils.threemf_tools.extract_filament_usage_from_3mf", extract_mock),
            patch("backend.app.core.config.settings") as mock_settings,
        ):
            mock_settings.base_dir = MagicMock()
            mock_path = MagicMock()
            mock_path.exists.return_value = True

            # No plate_id kwarg — direct/library Print flow.
            await _track_from_3mf(
                printer_id=1,
                archive_id=None,
                status="completed",
                print_name="DirectPrint",
                handled_trays=set(),
                printer_manager=printer_manager,
                db=db,
                tray_now_at_start=0,
                threemf_path=mock_path,
            )

        assert extract_mock.call_args.args[1] is None