"""Unit tests for 3MF parsing utilities (threemf_tools.py).

Tests G-code parsing, filament length-to-weight conversion,
and cumulative layer usage lookup.
"""

import io
import math
import zipfile

from backend.app.utils.threemf_tools import (
    extract_filament_usage_from_3mf,
    get_cumulative_usage_at_layer,
    mm_to_grams,
    parse_gcode_layer_filament_usage,
)


def create_mock_3mf(slice_info_content: str) -> io.BytesIO:
    """Create a mock 3MF file (ZIP) with slice_info.config content."""
    buffer = io.BytesIO()
    with zipfile.ZipFile(buffer, "w") as zf:
        zf.writestr("Metadata/slice_info.config", slice_info_content)
    buffer.seek(0)
    return buffer


class TestParseGcodeLayerFilamentUsage:
    """Tests for parse_gcode_layer_filament_usage()."""

    def test_single_filament_single_layer(self):
        """Single filament extruding on one layer."""
        gcode = """
M620 S0
G1 X10 Y10 E5.0
G1 X20 Y20 E3.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result == {0: {0: 8.0}}

    def test_multi_layer_single_filament(self):
        """Single filament across multiple layers."""
        gcode = """
M620 S0
G1 X10 Y10 E10.0
M73 L1
G1 X20 Y20 E5.0
M73 L2
G1 X30 Y30 E7.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result[0] == {0: 10.0}
        assert result[1] == {0: 15.0}
        assert result[2] == {0: 22.0}

    def test_multi_material(self):
        """Multiple filaments switching via M620."""
        gcode = """
M620 S0
G1 E10.0
M73 L1
M620 S1
G1 E5.0
M620 S0
G1 E3.0
M73 L2
G1 E2.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        # Layer 0: filament 0 = 10mm
        assert result[0] == {0: 10.0}
        # Layer 1: filament 0 = 13mm (10+3), filament 1 = 5mm
        assert result[1] == {0: 13.0, 1: 5.0}
        # Layer 2: filament 0 = 15mm (13+2)
        assert result[2] == {0: 15.0, 1: 5.0}

    def test_retractions_ignored(self):
        """Negative E values (retractions) should be ignored."""
        gcode = """
M620 S0
G1 E10.0
G1 E-2.0
G1 E5.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result == {0: {0: 15.0}}

    def test_m620_s255_unloads(self):
        """M620 S255 means unload - extrusion after should be ignored."""
        gcode = """
M620 S0
G1 E10.0
M620 S255
G1 E5.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result == {0: {0: 10.0}}

    def test_m620_with_suffix(self):
        """M620 S0A format (filament ID with suffix letter)."""
        gcode = """
M620 S0A
G1 E10.0
M620 S1A
G1 E5.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result == {0: {0: 10.0, 1: 5.0}}

    def test_comments_ignored(self):
        """Comment lines and inline comments are ignored."""
        gcode = """
; This is a comment
M620 S0
G1 X10 E5.0 ; inline comment with E value
G1 E3.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result == {0: {0: 8.0}}

    def test_empty_gcode(self):
        """Empty G-code returns empty dict."""
        assert parse_gcode_layer_filament_usage("") == {}
        assert parse_gcode_layer_filament_usage("\n\n\n") == {}

    def test_no_extrusion(self):
        """G-code with moves but no extrusion."""
        gcode = """
G1 X10 Y10
G1 X20 Y20
"""
        assert parse_gcode_layer_filament_usage(gcode) == {}

    def test_no_active_filament_extrusion_ignored(self):
        """Extrusion before any M620 is ignored (no active filament)."""
        gcode = """
G1 E10.0
M620 S0
G1 E5.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result == {0: {0: 5.0}}

    def test_g0_g2_g3_extrusion(self):
        """G0, G2, G3 with E parameter are also tracked."""
        gcode = """
M620 S0
G0 E1.0
G1 E2.0
G2 E3.0
G3 E4.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result == {0: {0: 10.0}}

    def test_cumulative_across_layers(self):
        """Values are cumulative, not per-layer."""
        gcode = """
M620 S0
G1 E100.0
M73 L1
G1 E100.0
M73 L2
G1 E100.0
"""
        result = parse_gcode_layer_filament_usage(gcode)
        assert result[0] == {0: 100.0}
        assert result[1] == {0: 200.0}
        assert result[2] == {0: 300.0}


class TestMmToGrams:
    """Tests for mm_to_grams()."""

    def test_default_pla_175(self):
        """Default PLA 1.75mm conversion."""
        # 1000mm of 1.75mm PLA at 1.24 g/cm³
        # Volume = π × (0.0875cm)² × 100cm = 2.405cm³
        # Weight = 2.405 × 1.24 = 2.982g
        result = mm_to_grams(1000.0)
        expected = math.pi * (0.0875**2) * 100 * 1.24
        assert abs(result - expected) < 0.001

    def test_zero_length(self):
        """Zero length returns zero weight."""
        assert mm_to_grams(0.0) == 0.0

    def test_custom_diameter(self):
        """Custom diameter (2.85mm) changes result."""
        result_175 = mm_to_grams(1000.0, diameter_mm=1.75)
        result_285 = mm_to_grams(1000.0, diameter_mm=2.85)
        # 2.85mm filament has more volume per mm
        assert result_285 > result_175
        ratio = (2.85 / 1.75) ** 2  # Volume scales with diameter²
        assert abs(result_285 / result_175 - ratio) < 0.001

    def test_custom_density(self):
        """Different density (ABS vs PLA)."""
        pla = mm_to_grams(1000.0, density_g_cm3=1.24)
        abs_ = mm_to_grams(1000.0, density_g_cm3=1.04)
        assert pla > abs_
        assert abs(pla / abs_ - 1.24 / 1.04) < 0.001

    def test_known_value(self):
        """Verify against a known calculation.

        1m (1000mm) of 1.75mm PLA at 1.24 g/cm³:
        r = 0.0875 cm, L = 100 cm
        V = π × 0.0875² × 100 = 2.4053 cm³
        m = 2.4053 × 1.24 = 2.9826 g
        """
        result = mm_to_grams(1000.0, 1.75, 1.24)
        assert abs(result - 2.9826) < 0.01


class TestGetCumulativeUsageAtLayer:
    """Tests for get_cumulative_usage_at_layer()."""

    def test_exact_layer_match(self):
        """Target layer exists exactly in the data."""
        data = {0: {0: 100.0}, 5: {0: 500.0}, 10: {0: 1000.0}}
        assert get_cumulative_usage_at_layer(data, 5) == {0: 500.0}

    def test_between_layers(self):
        """Target is between recorded layers - uses the closest lower one."""
        data = {0: {0: 100.0}, 5: {0: 500.0}, 10: {0: 1000.0}}
        # Layer 7 is between 5 and 10, should return layer 5's data
        assert get_cumulative_usage_at_layer(data, 7) == {0: 500.0}

    def test_beyond_last_layer(self):
        """Target is beyond the last recorded layer."""
        data = {0: {0: 100.0}, 5: {0: 500.0}}
        assert get_cumulative_usage_at_layer(data, 100) == {0: 500.0}

    def test_before_first_layer(self):
        """Target is before any recorded data."""
        data = {5: {0: 500.0}, 10: {0: 1000.0}}
        assert get_cumulative_usage_at_layer(data, 3) == {}

    def test_empty_data(self):
        """Empty layer_usage returns empty dict."""
        assert get_cumulative_usage_at_layer({}, 5) == {}

    def test_none_data(self):
        """None layer_usage returns empty dict."""
        assert get_cumulative_usage_at_layer(None, 5) == {}

    def test_multi_filament(self):
        """Multi-filament data at target layer."""
        data = {
            0: {0: 50.0},
            5: {0: 200.0, 1: 100.0},
            10: {0: 400.0, 1: 250.0, 2: 50.0},
        }
        result = get_cumulative_usage_at_layer(data, 8)
        assert result == {0: 200.0, 1: 100.0}

    def test_layer_zero(self):
        """Target layer 0."""
        data = {0: {0: 10.0}, 1: {0: 20.0}}
        assert get_cumulative_usage_at_layer(data, 0) == {0: 10.0}


class TestExtractFilamentUsageFrom3mf:
    """Tests for extract_filament_usage_from_3mf function."""

    def test_extract_single_filament(self, tmp_path):
        """Test extracting a single filament."""
        xml_content = """<?xml version="1.0" encoding="UTF-8"?>
        <config>
            <filament id="1" used_g="50.5" type="PLA" color="#FF0000"/>
        </config>
        """
        mock_3mf = create_mock_3mf(xml_content)
        file_path = tmp_path / "test.3mf"
        file_path.write_bytes(mock_3mf.read())

        result = extract_filament_usage_from_3mf(file_path)

        assert len(result) == 1
        assert result[0]["slot_id"] == 1
        assert result[0]["used_g"] == 50.5
        assert result[0]["type"] == "PLA"
        assert result[0]["color"] == "#FF0000"

    def test_extract_multiple_filaments(self, tmp_path):
        """Test extracting multiple filaments."""
        xml_content = """<?xml version="1.0" encoding="UTF-8"?>
        <config>
            <filament id="1" used_g="50.5" type="PLA" color="#FF0000"/>
            <filament id="2" used_g="30.2" type="PETG" color="#00FF00"/>
            <filament id="3" used_g="10.0" type="ABS" color="#0000FF"/>
        </config>
        """
        mock_3mf = create_mock_3mf(xml_content)
        file_path = tmp_path / "test.3mf"
        file_path.write_bytes(mock_3mf.read())

        result = extract_filament_usage_from_3mf(file_path)

        assert len(result) == 3
        assert result[0]["slot_id"] == 1
        assert result[1]["slot_id"] == 2
        assert result[2]["slot_id"] == 3

    def test_extract_filament_with_plate_id(self, tmp_path):
        """Test extracting filament for a specific plate."""
        xml_content = """<?xml version="1.0" encoding="UTF-8"?>
        <config>
            <plate>
                <metadata key="index" value="1"/>
                <filament id="1" used_g="25.0" type="PLA" color="#FF0000"/>
            </plate>
            <plate>
                <metadata key="index" value="2"/>
                <filament id="1" used_g="75.0" type="PETG" color="#00FF00"/>
            </plate>
        </config>
        """
        mock_3mf = create_mock_3mf(xml_content)
        file_path = tmp_path / "test.3mf"
        file_path.write_bytes(mock_3mf.read())

        result = extract_filament_usage_from_3mf(file_path, plate_id=2)

        assert len(result) == 1
        assert result[0]["used_g"] == 75.0
        assert result[0]["type"] == "PETG"

    def test_missing_slice_info_returns_empty(self, tmp_path):
        """Test that missing slice_info.config returns empty list."""
        buffer = io.BytesIO()
        with zipfile.ZipFile(buffer, "w") as zf:
            zf.writestr("other_file.txt", "content")
        buffer.seek(0)

        file_path = tmp_path / "test.3mf"
        file_path.write_bytes(buffer.read())

        result = extract_filament_usage_from_3mf(file_path)

        assert result == []

    def test_invalid_file_returns_empty(self, tmp_path):
        """Test that invalid file returns empty list."""
        file_path = tmp_path / "invalid.3mf"
        file_path.write_text("not a zip file")

        result = extract_filament_usage_from_3mf(file_path)

        assert result == []

    def test_nonexistent_file_returns_empty(self, tmp_path):
        """Test that nonexistent file returns empty list."""
        file_path = tmp_path / "nonexistent.3mf"

        result = extract_filament_usage_from_3mf(file_path)

        assert result == []

    def test_filament_without_id_is_skipped(self, tmp_path):
        """Test that filament without id is skipped."""
        xml_content = """<?xml version="1.0" encoding="UTF-8"?>
        <config>
            <filament used_g="50.5" type="PLA" color="#FF0000"/>
            <filament id="2" used_g="30.0" type="PETG" color="#00FF00"/>
        </config>
        """
        mock_3mf = create_mock_3mf(xml_content)
        file_path = tmp_path / "test.3mf"
        file_path.write_bytes(mock_3mf.read())

        result = extract_filament_usage_from_3mf(file_path)

        assert len(result) == 1
        assert result[0]["slot_id"] == 2

    def test_invalid_used_g_is_skipped(self, tmp_path):
        """Test that filament with invalid used_g is skipped."""
        xml_content = """<?xml version="1.0" encoding="UTF-8"?>
        <config>
            <filament id="1" used_g="invalid" type="PLA" color="#FF0000"/>
            <filament id="2" used_g="30.0" type="PETG" color="#00FF00"/>
        </config>
        """
        mock_3mf = create_mock_3mf(xml_content)
        file_path = tmp_path / "test.3mf"
        file_path.write_bytes(mock_3mf.read())

        result = extract_filament_usage_from_3mf(file_path)

        assert len(result) == 1
        assert result[0]["slot_id"] == 2

    def test_missing_optional_fields(self, tmp_path):
        """Test that missing type and color default to empty string."""
        xml_content = """<?xml version="1.0" encoding="UTF-8"?>
        <config>
            <filament id="1" used_g="50.5"/>
        </config>
        """
        mock_3mf = create_mock_3mf(xml_content)
        file_path = tmp_path / "test.3mf"
        file_path.write_bytes(mock_3mf.read())

        result = extract_filament_usage_from_3mf(file_path)

        assert len(result) == 1
        assert result[0]["type"] == ""
        assert result[0]["color"] == ""