"""Unit tests for G-code injection into 3MF files (#422)."""

import tempfile
import zipfile
from pathlib import Path

from backend.app.utils.threemf_tools import (
    _inject_start_at_marker,
    _parse_3mf_gcode_header,
    _substitute_placeholders,
    inject_gcode_into_3mf,
)


def _make_temp_path(suffix=".3mf") -> Path:
    """Create a temp file path without leaving it open (avoids SIM115)."""
    fd, name = tempfile.mkstemp(suffix=suffix)
    import os

    os.close(fd)
    return Path(name)


def _make_test_3mf(gcode_content: str = "G28\nG1 X0 Y0\nM400\n", plate_id: int = 1) -> Path:
    """Create a minimal 3MF file with embedded G-code for testing."""
    tmp_path = _make_temp_path()

    with zipfile.ZipFile(tmp_path, "w", zipfile.ZIP_DEFLATED) as zf:
        zf.writestr(f"Metadata/plate_{plate_id}.gcode", gcode_content)
        zf.writestr("Metadata/slice_info.config", "<config></config>")
        zf.writestr("3D/3dmodel.model", "<model></model>")

    return tmp_path


class TestInjectGcodeInto3mf:
    """Tests for inject_gcode_into_3mf()."""

    def test_inject_start_gcode(self):
        """Start G-code is prepended before the original content."""
        source = _make_test_3mf("G28\nM400\n")
        try:
            result = inject_gcode_into_3mf(source, 1, "M117 Start\nG92 E0", None)
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert gcode.startswith("M117 Start\nG92 E0\n")
            assert "G28\nM400\n" in gcode
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_inject_end_gcode(self):
        """End G-code is appended after the original content."""
        source = _make_test_3mf("G28\nM400")
        try:
            result = inject_gcode_into_3mf(source, 1, None, "M104 S0\nG28 X")
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert gcode.endswith("M104 S0\nG28 X\n")
            assert gcode.startswith("G28\nM400")
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_inject_both_start_and_end(self):
        """Both start and end G-code are injected."""
        source = _make_test_3mf("G28\n")
        try:
            result = inject_gcode_into_3mf(source, 1, "; START", "; END")
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert gcode.startswith("; START\n")
            assert gcode.endswith("; END\n")
            assert "G28" in gcode
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_no_injection_returns_none(self):
        """Returns None when both start and end are None."""
        source = _make_test_3mf()
        try:
            result = inject_gcode_into_3mf(source, 1, None, None)
            assert result is None
        finally:
            source.unlink(missing_ok=True)

    def test_empty_strings_returns_none(self):
        """Returns None when both start and end are empty strings."""
        source = _make_test_3mf()
        try:
            result = inject_gcode_into_3mf(source, 1, "", "")
            assert result is None
        finally:
            source.unlink(missing_ok=True)

    def test_plate_id_selection(self):
        """Injects into the correct plate's G-code file."""
        source = _make_temp_path()

        with zipfile.ZipFile(source, "w", zipfile.ZIP_DEFLATED) as zf:
            zf.writestr("Metadata/plate_1.gcode", "PLATE1\n")
            zf.writestr("Metadata/plate_2.gcode", "PLATE2\n")

        try:
            result = inject_gcode_into_3mf(source, 2, "; INJECTED", None)
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                plate1 = zf.read("Metadata/plate_1.gcode").decode("utf-8")
                plate2 = zf.read("Metadata/plate_2.gcode").decode("utf-8")

            # Only plate 2 should be modified
            assert plate1 == "PLATE1\n"
            assert plate2.startswith("; INJECTED\n")
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_preserves_other_files(self):
        """Non-gcode files in the 3MF are preserved unchanged."""
        source = _make_test_3mf()
        try:
            result = inject_gcode_into_3mf(source, 1, "; START", None)
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                names = zf.namelist()
                assert "Metadata/slice_info.config" in names
                assert "3D/3dmodel.model" in names
                config = zf.read("Metadata/slice_info.config").decode("utf-8")
                assert config == "<config></config>"
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_no_gcode_file_returns_none(self):
        """Returns None when the 3MF has no gcode files."""
        source = _make_temp_path()

        with zipfile.ZipFile(source, "w", zipfile.ZIP_DEFLATED) as zf:
            zf.writestr("3D/3dmodel.model", "<model></model>")

        try:
            result = inject_gcode_into_3mf(source, 1, "; START", None)
            assert result is None
        finally:
            source.unlink(missing_ok=True)

    def test_invalid_file_returns_none(self):
        """Returns None for a non-ZIP file."""
        source = _make_temp_path()
        source.write_bytes(b"not a zip file")

        try:
            result = inject_gcode_into_3mf(source, 1, "; START", None)
            assert result is None
        finally:
            source.unlink(missing_ok=True)

    def test_fallback_to_first_gcode(self):
        """Falls back to first gcode file when plate-specific not found."""
        source = _make_temp_path()

        with zipfile.ZipFile(source, "w", zipfile.ZIP_DEFLATED) as zf:
            zf.writestr("Metadata/plate_1.gcode", "ORIGINAL\n")

        try:
            # Request plate 5 which doesn't exist — should fall back to plate_1
            result = inject_gcode_into_3mf(source, 5, "; INJECTED", None)
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert gcode.startswith("; INJECTED\n")
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_original_file_unchanged(self):
        """The source 3MF is never modified."""
        source = _make_test_3mf("ORIGINAL\n")
        try:
            result = inject_gcode_into_3mf(source, 1, "; START", "; END")
            assert result is not None

            # Verify original is untouched
            with zipfile.ZipFile(source, "r") as zf:
                original = zf.read("Metadata/plate_1.gcode").decode("utf-8")
            assert original == "ORIGINAL\n"
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)


# Realistic Bambu / Orca header + startup block — the start-gcode marker is the
# anchor point #422 reviewers (DevScarabyte, pleite) reported as the correct
# injection point. Snippets injected before this should land *after* the bed
# heat / homing / nozzle prime sequence, not before it.
_BAMBU_GCODE_TEMPLATE = """\
; HEADER_BLOCK_START
; BambuStudio 02.06.00.51
; total layer number: 80
; total filament length [mm] : 12155.34
; total filament weight [g] : 36.55
; max_z_height: 16.00
; HEADER_BLOCK_END
; MACHINE_START_GCODE_BEGIN
M104 S220 ; preheat
G28 ; home
M109 S220 ; wait for nozzle
G92 E0 ; reset extruder
; MACHINE_START_GCODE_END
G1 X10 Y10 Z0.2
G1 X100 Y100 E5
M104 S0
"""


class TestStartAnchoredInjection:
    """Tests for #422 follow-up: start g-code injected at MACHINE_START_GCODE_END."""

    def test_start_lands_after_printer_startup(self):
        """Start snippet sits immediately before MACHINE_START_GCODE_END, not at file head."""
        source = _make_test_3mf(_BAMBU_GCODE_TEMPLATE)
        try:
            result = inject_gcode_into_3mf(source, 1, "; SWAPMOD-START", None)
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            # Original file head is preserved — snippet does NOT prepend.
            assert gcode.startswith("; HEADER_BLOCK_START\n")
            # Snippet sits right above the marker.
            marker_idx = gcode.index("; MACHINE_START_GCODE_END")
            snippet_idx = gcode.index("; SWAPMOD-START")
            assert snippet_idx < marker_idx
            # Nothing else between snippet and marker except the trailing newline.
            between = gcode[snippet_idx:marker_idx]
            assert between == "; SWAPMOD-START\n"
            # Printer's own startup commands still come BEFORE the snippet.
            startup_idx = gcode.index("M109 S220")
            assert startup_idx < snippet_idx
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_no_marker_falls_back_to_prepend(self):
        """Files without MACHINE_START_GCODE_END (older slicers) keep prepend behaviour."""
        source = _make_test_3mf("G28\nM400\n")
        try:
            result = inject_gcode_into_3mf(source, 1, "; LEGACY-START", None)
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert gcode.startswith("; LEGACY-START\n")
            assert "G28" in gcode
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_end_still_appended_at_eof(self):
        """End g-code keeps the existing append-to-EOF behaviour even with marker present."""
        source = _make_test_3mf(_BAMBU_GCODE_TEMPLATE)
        try:
            result = inject_gcode_into_3mf(source, 1, None, "; SWAPMOD-END")
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert gcode.endswith("; SWAPMOD-END\n")
            # Marker anchor is irrelevant for end snippets.
            assert gcode.index("; SWAPMOD-END") > gcode.index("; MACHINE_START_GCODE_END")
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)


class TestPlaceholderSubstitution:
    """Tests for #422 follow-up: {placeholder} substitution from 3MF header values."""

    def test_max_z_height_substituted_in_end_snippet(self):
        """`G1 Z{max_layer_z}` resolves to the model's actual top-layer Z (DevScarabyte safety bug)."""
        source = _make_test_3mf(_BAMBU_GCODE_TEMPLATE)
        try:
            # Prusa-style alias: max_layer_z → max_z_height in the Bambu header
            result = inject_gcode_into_3mf(source, 1, None, "G1 Z{max_layer_z} F600")
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            # max_z_height in the template is 16.00 — the dangerous Z1 fallback is gone.
            assert "G1 Z16.00 F600" in gcode
            assert "{max_layer_z}" not in gcode
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_direct_header_key_lookup(self):
        """Snippets can reference normalised header keys directly without going through aliases."""
        source = _make_test_3mf(_BAMBU_GCODE_TEMPLATE)
        try:
            result = inject_gcode_into_3mf(
                source, 1, None, "; layers={total_layer_number} weight={total_filament_weight}"
            )
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert "; layers=80 weight=36.55" in gcode
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_unknown_placeholder_left_intact(self):
        """A typo or unsupported placeholder is preserved verbatim instead of becoming empty."""
        source = _make_test_3mf(_BAMBU_GCODE_TEMPLATE)
        try:
            result = inject_gcode_into_3mf(source, 1, None, "; nope={does_not_exist}")
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert "; nope={does_not_exist}" in gcode
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)

    def test_no_placeholders_no_header_required(self):
        """Snippets without placeholders inject correctly even when the header is absent."""
        source = _make_test_3mf("G28\nM400\n")
        try:
            result = inject_gcode_into_3mf(source, 1, "; PLAIN", None)
            assert result is not None

            with zipfile.ZipFile(result, "r") as zf:
                gcode = zf.read("Metadata/plate_1.gcode").decode("utf-8")

            assert gcode.startswith("; PLAIN\n")
        finally:
            source.unlink(missing_ok=True)
            if result:
                result.unlink(missing_ok=True)


class TestHeaderParser:
    """Direct tests for `_parse_3mf_gcode_header`."""

    def test_parses_bambu_header_block(self):
        header = _parse_3mf_gcode_header(_BAMBU_GCODE_TEMPLATE)
        assert header["max_z_height"] == "16.00"
        assert header["total_layer_number"] == "80"
        # Units suffix is stripped from the key.
        assert header["total_filament_length"] == "12155.34"
        assert header["total_filament_weight"] == "36.55"

    def test_ignores_lines_outside_header_block(self):
        content = "; HEADER_BLOCK_START\n; key: in\n; HEADER_BLOCK_END\n; key: out\n"
        header = _parse_3mf_gcode_header(content)
        assert header == {"key": "in"}

    def test_returns_empty_when_no_header(self):
        assert _parse_3mf_gcode_header("G28\nG1 X0\n") == {}


class TestPlaceholderHelper:
    """Direct tests for `_substitute_placeholders`."""

    def test_substitutes_known_keys(self):
        assert _substitute_placeholders("Z={a} F={b}", {"a": "10", "b": "600"}) == "Z=10 F=600"

    def test_alias_resolves_to_underlying_key(self):
        assert _substitute_placeholders("Z={max_layer_z}", {"max_z_height": "16.00"}) == "Z=16.00"

    def test_unknown_left_verbatim(self):
        assert _substitute_placeholders("{nope}", {}) == "{nope}"


class TestStartMarkerHelper:
    """Direct tests for `_inject_start_at_marker`."""

    def test_inserts_before_marker_line(self):
        content = "first\nsecond\n; MACHINE_START_GCODE_END\ntail\n"
        result = _inject_start_at_marker(content, "INJECTED")
        assert result == "first\nsecond\nINJECTED\n; MACHINE_START_GCODE_END\ntail\n"

    def test_marker_at_start_of_file(self):
        content = "; MACHINE_START_GCODE_END\nrest\n"
        result = _inject_start_at_marker(content, "INJECTED")
        assert result == "INJECTED\n; MACHINE_START_GCODE_END\nrest\n"

    def test_missing_marker_falls_back_to_prepend(self):
        content = "G28\nG1 X0\n"
        result = _inject_start_at_marker(content, "INJECTED")
        assert result == "INJECTED\nG28\nG1 X0\n"