import { describe, it, expect } from 'vitest';
import { createBuffer2D, dwtForward, dwtInverse, yPlaneToBuffer, bufferToYPlane } from '../core/dwt.js';

describe('DWT', () => {
  it('should round-trip a simple buffer (1 level)', () => {
    const width = 16;
    const height = 16;
    const buf = createBuffer2D(width, height);
    for (let i = 0; i < buf.data.length; i++) {
      buf.data[i] = Math.round(Math.random() * 255);
    }
    const original = new Float64Array(buf.data);

    const { buf: transformed, dims } = dwtForward(buf, 1);
    dwtInverse(transformed, dims);

    for (let i = 0; i < original.length; i++) {
      expect(transformed.data[i]).toBeCloseTo(original[i], 8);
    }
  });

  it('should round-trip a buffer (2 levels)', () => {
    const width = 64;
    const height = 64;
    const buf = createBuffer2D(width, height);
    for (let i = 0; i < buf.data.length; i++) {
      buf.data[i] = Math.round(Math.random() * 255);
    }
    const original = new Float64Array(buf.data);

    const { buf: transformed, dims } = dwtForward(buf, 2);
    dwtInverse(transformed, dims);

    for (let i = 0; i < original.length; i++) {
      expect(transformed.data[i]).toBeCloseTo(original[i], 8);
    }
  });

  it('should convert Y plane to buffer and back', () => {
    const width = 32;
    const height = 32;
    const yPlane = new Uint8Array(width * height);
    for (let i = 0; i < yPlane.length; i++) {
      yPlane[i] = Math.floor(Math.random() * 256);
    }

    const buf = yPlaneToBuffer(yPlane, width, height);
    const result = bufferToYPlane(buf);

    expect(result).toEqual(yPlane);
  });
});