import assert from "node:assert/strict";
import test from "node:test";

import { findColorBoundaryCrop, mapColorBoundaryCropToLimit } from "../src/ui/pages/CanvasWorkspace/canvas/colorBoundaryCrop.ts";

function imageFixture(width, height, background, region) {
  const data = new Uint8ClampedArray(width * height * 4);
  for (let y = 0; y < height; y += 1) {
    for (let x = 0; x < width; x += 1) {
      const offset = (y * width + x) * 4;
      const inside = x >= region.left && x < region.right && y >= region.top && y < region.bottom;
      const color = inside ? region.color(x, y) : background;
      data[offset] = color[0];
      data[offset + 1] = color[1];
      data[offset + 2] = color[2];
      data[offset + 3] = color[3] ?? 255;
    }
  }
  return { width, height, data };
}

test("finds the connected color-bounded region around a crop click", () => {
  const image = imageFixture(12, 10, [235, 235, 235, 255], {
    left: 3,
    top: 2,
    right: 9,
    bottom: 7,
    color: (x, y) => [64 + x, 72 + y, 80, 255]
  });

  assert.deepEqual(findColorBoundaryCrop(image, { x: 0.5, y: 0.4 }), {
    x: 0.25,
    y: 0.2,
    width: 0.5,
    height: 0.5
  });
});

test("uses the full analyzable area when no color boundary encloses the click", () => {
  const image = imageFixture(8, 6, [250, 250, 250, 255], {
    left: 0,
    top: 0,
    right: 0,
    bottom: 0,
    color: () => [0, 0, 0, 255]
  });

  assert.deepEqual(findColorBoundaryCrop(image, { x: 0.5, y: 0.5 }), { x: 0, y: 0, width: 1, height: 1 });
});

test("never expands automatic selection beyond the currently visible crop limit", () => {
  const visibleLimit = { x: 0.18, y: 0.12, width: 0.64, height: 0.7 };

  assert.deepEqual(mapColorBoundaryCropToLimit({ x: 0, y: 0, width: 1, height: 1 }, visibleLimit), visibleLimit);
  assert.deepEqual(mapColorBoundaryCropToLimit({ x: 0.25, y: 0.2, width: 0.5, height: 0.4 }, visibleLimit), {
    x: 0.34,
    y: 0.26,
    width: 0.32,
    height: 0.28
  });
});