using OpenNest.Converters;
using OpenNest.Geometry;
using OpenNest.Shapes;

namespace OpenNest.Tests.Splitting;

public class DrawingSplitterTests
{
    [Fact]
    public void Split_Rectangle_Vertical_ProducesTwoPieces()
    {
        var drawing = new RectangleShape { Name = "RECT", Length = 100, Width = 50 }.GetDrawing();
        var splitLines = new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        Assert.Equal(2, results.Count);
        Assert.Equal("RECT-1", results[0].Name);
        Assert.Equal("RECT-2", results[1].Name);

        // Each piece should have area close to half the original
        var totalArea = results.Sum(d => d.Area);
        Assert.Equal(drawing.Area, totalArea, 1);
    }

    [Fact]
    public void Split_Rectangle_Horizontal_ProducesTwoPieces()
    {
        var drawing = new RectangleShape { Name = "RECT", Length = 100, Width = 60 }.GetDrawing();
        var splitLines = new List<SplitLine> { new SplitLine(30.0, CutOffAxis.Horizontal) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        Assert.Equal(2, results.Count);
        Assert.Equal("RECT-1", results[0].Name);
        Assert.Equal("RECT-2", results[1].Name);
    }

    [Fact]
    public void Split_ThreePieces_NamesSequentially()
    {
        var drawing = new RectangleShape { Name = "PART", Length = 150, Width = 50 }.GetDrawing();
        var splitLines = new List<SplitLine>
        {
            new SplitLine(50.0, CutOffAxis.Vertical),
            new SplitLine(100.0, CutOffAxis.Vertical)
        };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        Assert.Equal(3, results.Count);
        Assert.Equal("PART-1", results[0].Name);
        Assert.Equal("PART-2", results[1].Name);
        Assert.Equal("PART-3", results[2].Name);
    }

    [Fact]
    public void Split_CopiesDrawingProperties()
    {
        var drawing = new RectangleShape { Name = "PART", Length = 100, Width = 50 }.GetDrawing();
        drawing.Color = System.Drawing.Color.Red;
        drawing.Priority = 5;

        var results = DrawingSplitter.Split(drawing,
            new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) },
            new SplitParameters());

        Assert.All(results, d =>
        {
            Assert.Equal(System.Drawing.Color.Red, d.Color);
            Assert.Equal(5, d.Priority);
        });
    }

    [Fact]
    public void Split_PiecesNormalizedToOrigin()
    {
        var drawing = new RectangleShape { Name = "PART", Length = 100, Width = 50 }.GetDrawing();
        var results = DrawingSplitter.Split(drawing,
            new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) },
            new SplitParameters());

        // Each piece's program bounding box should start near (0,0)
        foreach (var d in results)
        {
            var bb = d.Program.BoundingBox();
            Assert.True(bb.X < 1.0, $"Piece {d.Name} not normalized: X={bb.X}");
            Assert.True(bb.Y < 1.0, $"Piece {d.Name} not normalized: Y={bb.Y}");
        }
    }

    [Fact]
    public void Split_WithCutout_AssignsCutoutToCorrectPiece()
    {
        // Rectangle 100x50 with a small square cutout at (20,20)-(30,30)
        var perimeterEntities = new List<Entity>
        {
            new Line(new Vector(0, 0), new Vector(100, 0)),
            new Line(new Vector(100, 0), new Vector(100, 50)),
            new Line(new Vector(100, 50), new Vector(0, 50)),
            new Line(new Vector(0, 50), new Vector(0, 0))
        };
        var cutoutEntities = new List<Entity>
        {
            new Line(new Vector(20, 20), new Vector(30, 20)),
            new Line(new Vector(30, 20), new Vector(30, 30)),
            new Line(new Vector(30, 30), new Vector(20, 30)),
            new Line(new Vector(20, 30), new Vector(20, 20))
        };
        var allEntities = new List<Entity>();
        allEntities.AddRange(perimeterEntities);
        allEntities.AddRange(cutoutEntities);

        var pgm = ConvertGeometry.ToProgram(allEntities);
        var drawing = new Drawing("HOLE", pgm);

        // Split at X=50 — cutout is in the left half
        var results = DrawingSplitter.Split(drawing,
            new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) },
            new SplitParameters());

        Assert.Equal(2, results.Count);
        // Left piece should have smaller area (has the cutout)
        Assert.True(results[0].Area < results[1].Area,
            "Left piece should have less area due to cutout");
    }

    [Fact]
    public void Split_GridSplit_ProducesFourPieces()
    {
        var drawing = new RectangleShape { Name = "GRID", Length = 100, Width = 100 }.GetDrawing();
        var splitLines = new List<SplitLine>
        {
            new SplitLine(50.0, CutOffAxis.Vertical),
            new SplitLine(50.0, CutOffAxis.Horizontal)
        };
        var results = DrawingSplitter.Split(drawing, splitLines, new SplitParameters());

        Assert.Equal(4, results.Count);
        Assert.Equal("GRID-1", results[0].Name);
        Assert.Equal("GRID-2", results[1].Name);
        Assert.Equal("GRID-3", results[2].Name);
        Assert.Equal("GRID-4", results[3].Name);
    }

    [Fact]
    public void Split_Square_Vertical_PieceWidthsSumToOriginal()
    {
        var drawing = new RectangleShape { Name = "SQ", Length = 100, Width = 100 }.GetDrawing();
        var splitLines = new List<SplitLine> { new SplitLine(40.0, CutOffAxis.Vertical) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        Assert.Equal(2, results.Count);

        var bb1 = results[0].Program.BoundingBox();
        var bb2 = results[1].Program.BoundingBox();

        // Piece lengths should sum to original length
        Assert.Equal(100.0, bb1.Width + bb2.Width, 1);

        // Both pieces should have the same width as the original
        Assert.Equal(100.0, bb1.Length, 1);
        Assert.Equal(100.0, bb2.Length, 1);
    }

    [Fact]
    public void Split_Square_Horizontal_PieceHeightsSumToOriginal()
    {
        var drawing = new RectangleShape { Name = "SQ", Length = 100, Width = 100 }.GetDrawing();
        var splitLines = new List<SplitLine> { new SplitLine(60.0, CutOffAxis.Horizontal) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        Assert.Equal(2, results.Count);

        var bb1 = results[0].Program.BoundingBox();
        var bb2 = results[1].Program.BoundingBox();

        // Piece widths should sum to original width
        Assert.Equal(100.0, bb1.Length + bb2.Length, 1);

        // Both pieces should have the same length as the original
        Assert.Equal(100.0, bb1.Width, 1);
        Assert.Equal(100.0, bb2.Width, 1);
    }

    [Fact]
    public void Split_Square_Vertical_AreaPreserved()
    {
        var drawing = new RectangleShape { Name = "SQ", Length = 100, Width = 100 }.GetDrawing();
        var originalArea = drawing.Area;
        var splitLines = new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        var totalArea = results.Sum(d => d.Area);
        Assert.Equal(originalArea, totalArea, 1);
    }

    [Fact]
    public void Split_Square_Vertical_PiecesAreClosedPerimeters()
    {
        var drawing = new RectangleShape { Name = "SQ", Length = 100, Width = 100 }.GetDrawing();
        var splitLines = new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        foreach (var piece in results)
        {
            var entities = ConvertProgram.ToGeometry(piece.Program)
                .Where(e => e.Layer != SpecialLayers.Rapid).ToList();

            Assert.True(entities.Count >= 4, $"{piece.Name} should have at least 4 entities for a rectangle");

            // First entity start should connect to last entity end (closed shape)
            var firstStart = GetStartPoint(entities[0]);
            var lastEnd = GetEndPoint(entities[^1]);
            var closingGap = firstStart.DistanceTo(lastEnd);
            Assert.True(closingGap < 0.01,
                $"{piece.Name} is not closed: gap of {closingGap:F6} between last end and first start");

            // Consecutive entities should connect
            for (var i = 0; i < entities.Count - 1; i++)
            {
                var end = GetEndPoint(entities[i]);
                var start = GetStartPoint(entities[i + 1]);
                var gap = end.DistanceTo(start);
                Assert.True(gap < 0.01,
                    $"Gap of {gap:F6} between entities {i} and {i + 1} in {piece.Name}");
            }
        }
    }

    [Fact]
    public void Split_Square_Horizontal_PiecesAreClosedPerimeters()
    {
        var drawing = new RectangleShape { Name = "SQ", Length = 100, Width = 100 }.GetDrawing();
        var splitLines = new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Horizontal) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        foreach (var piece in results)
        {
            var entities = ConvertProgram.ToGeometry(piece.Program)
                .Where(e => e.Layer != SpecialLayers.Rapid).ToList();

            Assert.True(entities.Count >= 4, $"{piece.Name} should have at least 4 entities for a rectangle");

            var firstStart = GetStartPoint(entities[0]);
            var lastEnd = GetEndPoint(entities[^1]);
            var closingGap = firstStart.DistanceTo(lastEnd);
            Assert.True(closingGap < 0.01,
                $"{piece.Name} is not closed: gap of {closingGap:F6} between last end and first start");

            for (var i = 0; i < entities.Count - 1; i++)
            {
                var end = GetEndPoint(entities[i]);
                var start = GetStartPoint(entities[i + 1]);
                var gap = end.DistanceTo(start);
                Assert.True(gap < 0.01,
                    $"Gap of {gap:F6} between entities {i} and {i + 1} in {piece.Name}");
            }
        }
    }

    [Fact]
    public void Split_Square_AsymmetricSplit_PieceDimensionsMatchSplitPosition()
    {
        var drawing = new RectangleShape { Name = "SQ", Length = 100, Width = 100 }.GetDrawing();
        var splitLines = new List<SplitLine> { new SplitLine(30.0, CutOffAxis.Vertical) };
        var parameters = new SplitParameters { Type = SplitType.Straight };

        var results = DrawingSplitter.Split(drawing, splitLines, parameters);

        Assert.Equal(2, results.Count);

        var bb1 = results[0].Program.BoundingBox();
        var bb2 = results[1].Program.BoundingBox();

        // Left piece should be 30 long, right piece should be 70 long
        Assert.Equal(30.0, bb1.Width, 1);
        Assert.Equal(70.0, bb2.Width, 1);
    }

    [Fact]
    public void Split_CircleHole_NotOnSplitLine_PreservedInCorrectPiece()
    {
        // Rectangle 100x50 with a circle hole at (20, 25) radius 3
        // Split vertically at x=50 — hole is entirely in the left piece
        var perimeterEntities = new List<Entity>
        {
            new Line(new Vector(0, 0), new Vector(100, 0)),
            new Line(new Vector(100, 0), new Vector(100, 50)),
            new Line(new Vector(100, 50), new Vector(0, 50)),
            new Line(new Vector(0, 50), new Vector(0, 0))
        };
        var hole = new Circle(new Vector(20, 25), 3);
        var allEntities = new List<Entity>();
        allEntities.AddRange(perimeterEntities);
        allEntities.Add(hole);

        var pgm = ConvertGeometry.ToProgram(allEntities);
        var drawing = new Drawing("CIRC", pgm);

        var results = DrawingSplitter.Split(drawing,
            new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) },
            new SplitParameters());

        Assert.Equal(2, results.Count);

        // Left piece should have the hole — verify by checking it has arc entities
        var leftEntities = ConvertProgram.ToGeometry(results[0].Program)
            .Where(e => e.Layer != SpecialLayers.Rapid).ToList();
        var leftArcs = leftEntities.OfType<Arc>().ToList();

        // Decomposed circle = 2 arcs. Both should be present.
        Assert.True(leftArcs.Count >= 2,
            $"Left piece should have at least 2 arcs (full circle), but has {leftArcs.Count}");

        // Right piece should have no arcs (hole is on the left)
        var rightEntities = ConvertProgram.ToGeometry(results[1].Program)
            .Where(e => e.Layer != SpecialLayers.Rapid).ToList();
        var rightArcs = rightEntities.OfType<Arc>().ToList();
        Assert.Equal(0, rightArcs.Count);
    }

    [Fact]
    public void Split_DxfRoundTrip_CircleHolePreserved()
    {
        // Two semicircular arcs (decomposed circle) must survive DXF write→reimport.
        // Regression: GeometryOptimizer.TryJoinArcs merged them into a single arc
        // because it incorrectly handled the wrap-around case (π→2π written as π→0°).
        var perimeterEntities = new List<Entity>
        {
            new Line(new Vector(0, 0), new Vector(100, 0)),
            new Line(new Vector(100, 0), new Vector(100, 50)),
            new Line(new Vector(100, 50), new Vector(0, 50)),
            new Line(new Vector(0, 50), new Vector(0, 0))
        };
        var hole = new Circle(new Vector(20, 25), 3);
        var allEntities = new List<Entity>();
        allEntities.AddRange(perimeterEntities);
        allEntities.Add(hole);

        var pgm = ConvertGeometry.ToProgram(allEntities);
        var drawing = new Drawing("CIRC", pgm);
        drawing.Bends = new List<OpenNest.Bending.Bend>();

        // Split — the circle gets decomposed into two arcs
        var results = DrawingSplitter.Split(drawing,
            new List<SplitLine> { new SplitLine(50.0, CutOffAxis.Vertical) },
            new SplitParameters());

        Assert.Equal(2, results.Count);

        // Write left piece to DXF and re-import
        var tempPath = System.IO.Path.Combine(System.IO.Path.GetTempPath(), "split_roundtrip_test.dxf");
        try
        {
            var writer = new OpenNest.IO.SplitDxfWriter();
            writer.Write(tempPath, results[0]);

            var reimporter = new OpenNest.IO.DxfImporter();
            var reimportResult = reimporter.Import(tempPath);

            var afterArcs = reimportResult.Entities.OfType<Arc>().Count();
            var afterCircles = reimportResult.Entities.OfType<Circle>().Count();

            Assert.True(afterArcs + afterCircles * 2 >= 2,
                $"After DXF round-trip: {afterArcs} arcs, {afterCircles} circles (expected 2+ for full hole)");
        }
        finally
        {
            if (System.IO.File.Exists(tempPath))
                System.IO.File.Delete(tempPath);
        }
    }

    private static Vector GetStartPoint(Entity entity)
    {
        return entity switch
        {
            Line l => l.StartPoint,
            Arc a => a.StartPoint(),
            _ => new Vector(0, 0)
        };
    }

    private static Vector GetEndPoint(Entity entity)
    {
        return entity switch
        {
            Line l => l.EndPoint,
            Arc a => a.EndPoint(),
            _ => new Vector(0, 0)
        };
    }
}