import { beforeAll, describe, expect, it } from 'vitest';
import { bounds } from '../src/lib/geometry';
import { shapeFromPolygons } from '../src/lib/margin';
import { loadOpenCV, type CV } from '../src/lib/opencv-loader';

let cv: CV;
beforeAll(async () => {
  ({ cv } = await loadOpenCV());
});

const outer = [{ x: 40, y: 30 }, { x: 160, y: 30 }, { x: 160, y: 130 }, { x: 40, y: 130 }];
const hole = [{ x: 90, y: 70 }, { x: 110, y: 70 }, { x: 110, y: 90 }, { x: 90, y: 90 }];
const near = (actual: number, expected: number) => expect(Math.abs(actual - expected)).toBeLessThanOrEqual(2);

describe('shapeFromPolygons', () => {
  it('traces the drawn outline and hole', () => {
    const shape = shapeFromPolygons(cv, 200, 160, { outer, holes: [hole] }, 0)!;
    const b = bounds(shape.outer);
    near(b.minX, 40); near(b.maxX, 160); near(b.minY, 30); near(b.maxY, 130);
    expect(shape.holes).toHaveLength(1);
  });

  it('applies the margin to outline and hole', () => {
    const shape = shapeFromPolygons(cv, 200, 160, { outer, holes: [hole] }, -5)!;
    near(bounds(shape.outer).minX, 45);
    near(bounds(shape.holes[0]).minX, 84);
  });

  it('returns null for an outline with fewer than 3 points', () => {
    expect(shapeFromPolygons(cv, 200, 160, { outer: outer.slice(0, 2), holes: [] }, 0)).toBeNull();
  });
});