import { describe, expect, it } from "vitest";
import {
  correctedDimensions,
  isValidQuad,
  moveQuadPoint,
  polygonArea,
  squareToQuad,
} from "../../src/scan/geometry";
import { DEFAULT_QUAD, type Quad } from "../../src/scan/types";

describe("document geometry", () => {
  it("validates ordered convex quadrilaterals", () => {
    expect(isValidQuad(DEFAULT_QUAD)).toBe(true);
    expect(polygonArea(DEFAULT_QUAD)).toBe(1);
    expect(
      isValidQuad([
        { x: 0, y: 0 },
        { x: 1, y: 1 },
        { x: 1, y: 0 },
        { x: 0, y: 1 },
      ]),
    ).toBe(false);
  });

  it("rejects a dragged corner that would invert the page", () => {
    expect(moveQuadPoint(DEFAULT_QUAD, 0, { x: 0.9, y: 0.9 })).toEqual(
      DEFAULT_QUAD,
    );
    expect(moveQuadPoint(DEFAULT_QUAD, 0, { x: 0.1, y: 0.1 })[0]).toEqual({
      x: 0.1,
      y: 0.1,
    });
  });

  it("maps every destination corner onto the selected source corner", () => {
    const quad: Quad = [
      { x: 0.12, y: 0.08 },
      { x: 0.9, y: 0.16 },
      { x: 0.82, y: 0.94 },
      { x: 0.05, y: 0.8 },
    ];
    const map = squareToQuad(quad);
    expect(map(0, 0)).toEqual(quad[0]);
    expect(map(1, 0).x).toBeCloseTo(quad[1].x);
    expect(map(1, 1).y).toBeCloseTo(quad[2].y);
    expect(map(0, 1).x).toBeCloseTo(quad[3].x);
  });

  it("preserves aspect and obeys the pixel budget", () => {
    expect(correctedDimensions(DEFAULT_QUAD, 4000, 3000, 1_000_000)).toEqual({
      width: 1154,
      height: 866,
      scale: expect.closeTo(Math.sqrt(1 / 12), 8),
    });
  });
});