import { describe, expect, it } from 'vitest';
import ClipperLib from 'clipper-lib';
import { fireplace, rectangle } from '../src/lib/defaults';
import { buildGeometry, insetPolygon, normalizeAngle, signedArea } from '../src/lib/geometry';
import { planSkirting } from '../src/lib/skirting';
import { skirtingPolygon } from '../src/lib/skirting-polygon';
import type { Point, Room } from '../src/lib/types';

const settings = { stockLength: 2400, thickness: 18, minLength: 200, kerf: 3 };

function overlap(a: Point[], b: Point[]): number {
  const clipper = new ClipperLib.Clipper();
  const path = (points: Point[]) =>
    points.map((point) => ({
      X: Math.round(point.x * 1000),
      Y: Math.round(point.y * 1000),
    }));
  clipper.AddPath(path(a), ClipperLib.PolyType.ptSubject, true);
  clipper.AddPath(path(b), ClipperLib.PolyType.ptClip, true);
  const intersection: ClipperLib.Paths = [];
  clipper.Execute(ClipperLib.ClipType.ctIntersection, intersection);
  return intersection.reduce(
    (sum, polygon) => sum + Math.abs(ClipperLib.Clipper.Area(polygon)) / 1e6,
    0,
  );
}

function expectCompleteSkirting(room: Room) {
  room.walls.forEach((wall) => {
    wall.doors = [];
  });
  const geometry = buildGeometry(room, 1);
  const plan = planSkirting([room], settings, 1);
  expect(plan.issues.filter((issue) => issue.severity === 'error')).toEqual([]);
  const polygons = plan.pieces.map((piece) =>
    skirtingPolygon(piece, settings.thickness, signedArea(geometry.vertices)),
  );
  const inner = insetPolygon(geometry.vertices, settings.thickness);
  // Exact area of the mitred perimeter band; unlike clipping, this does not
  // round angled intersections to the nearest 0.001 mm.
  const orientation = Math.sign(signedArea(geometry.vertices));
  const cornerArea = geometry.edges.reduce((sum, edge, index, edges) => {
    const turn =
      normalizeAngle(edges[(index + 1) % edges.length].heading - edge.heading) * orientation;
    return sum + settings.thickness ** 2 * Math.tan((turn * Math.PI) / 360);
  }, 0);
  const expectedArea = geometry.perimeter * settings.thickness - cornerArea;
  expect(polygons.reduce((sum, polygon) => sum + Math.abs(signedArea(polygon)), 0)).toBeCloseTo(
    expectedArea,
    5,
  );
  for (let i = 0; i < polygons.length; i++) {
    const polygon = polygons[i];
    // Inset and intersection coordinates each round to a 0.001 mm grid.
    const clippingTolerance = polygon.reduce((sum, point, index) => {
      const next = polygon[(index + 1) % polygon.length];
      return sum + Math.hypot(next.x - point.x, next.y - point.y) / 1000;
    }, 0);
    const piece = plan.pieces[i];
    const installed = piece.installedTemplate!;
    expect(Math.hypot(polygon[0].x - piece.start.x, polygon[0].y - piece.start.y)).toBeCloseTo(
      Math.abs(installed[0].x - piece.template![0].x),
    );
    expect(Math.hypot(polygon[1].x - piece.end.x, polygon[1].y - piece.end.y)).toBeCloseTo(
      Math.abs(installed[1].x - piece.template![1].x),
    );
    expect(
      Math.abs(overlap(polygon, geometry.vertices) - Math.abs(signedArea(polygon))),
    ).toBeLessThan(clippingTolerance);
    for (const innerPolygon of inner)
      expect(overlap(polygon, innerPolygon)).toBeLessThan(clippingTolerance);
    for (let j = i + 1; j < polygons.length; j++)
      expect(overlap(polygon, polygons[j])).toBeLessThan(clippingTolerance);
  }
  return plan;
}

describe('installed skirting polygons', () => {
  it.each([1, -1])(
    'covers a rectangle including uncut stock without overlapping coped bodies (orientation %i)',
    (orientation) => {
      const room = rectangle();
      room.walls.forEach((wall) => {
        wall.turn *= orientation;
      });
      const plan = expectCompleteSkirting(room);
      expect(plan.pieces.some((piece) => piece.id.startsWith('SU'))).toBe(true);
    },
  );

  it.each([1, -1])(
    'joins fireplace mitres without gaps or overlaps (orientation %i)',
    (orientation) => {
      const room = fireplace('fire', 'Fireplace');
      room.walls.forEach((wall) => {
        wall.turn *= orientation;
      });
      const plan = expectCompleteSkirting(room);
      expect(
        plan.pieces.reduce(
          (sum, piece) =>
            sum + Number(piece.leftType === 'external') + Number(piece.rightType === 'external'),
          0,
        ),
      ).toBe(4);
    },
  );

  it.each([60, -60, 120, -120])(
    'matches the room boundary at angled coped internal joints (%i degrees)',
    (turn) => {
      expectCompleteSkirting({
        id: 'triangle',
        name: 'Triangle',
        direction: 0,
        walls: Array.from({ length: 360 / Math.abs(turn) }, (_, index) => ({
          id: `w${index}`,
          length: 3000,
          turn,
          doors: [],
        })),
      });
    },
  );
});