import { describe, it, expect, beforeAll, afterAll } from 'vitest';
import fs from 'node:fs/promises';
import path from 'node:path';
import os from 'node:os';
import sharp from 'sharp';
import { registerImageConverters, buildFormatOptions } from '../../src/converters/image.js';
import { resolve, listTargetFormats } from '../../src/converters/registry.js';
import { detectInputMime } from '../../src/mime.js';

let tmpDir;
let noisyPngPath;

beforeAll(async () => {
  registerImageConverters();
  tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'converter-image-'));
  noisyPngPath = path.join(tmpDir, 'noisy.png');
  await sharp({
    create: {
      width: 256,
      height: 256,
      channels: 3,
      noise: { type: 'gaussian', mean: 128, sigma: 40 },
    },
  })
    .png()
    .toFile(noisyPngPath);
});

afterAll(async () => {
  await fs.rm(tmpDir, { recursive: true, force: true });
});

describe('buildFormatOptions', () => {
  it('returns an empty object when quality is not set', () => {
    expect(buildFormatOptions('jpeg', null)).toEqual({});
  });

  it('maps quality to the quality option for jpeg/webp/avif/tiff', () => {
    expect(buildFormatOptions('jpeg', 40)).toEqual({ quality: 40 });
    expect(buildFormatOptions('webp', 40)).toEqual({ quality: 40 });
    expect(buildFormatOptions('avif', 40)).toEqual({ quality: 40 });
    expect(buildFormatOptions('tiff', 40)).toEqual({ quality: 40 });
  });

  it('maps quality to compressionLevel for png', () => {
    expect(buildFormatOptions('png', 3)).toEqual({ compressionLevel: 3 });
  });

  it('ignores quality for gif', () => {
    expect(buildFormatOptions('gif', 5)).toEqual({});
  });
});

describe('image converters', () => {
  it('registers every pair among the supported formats', () => {
    const targets = listTargetFormats('png').sort();
    expect(targets).toEqual(['avif', 'gif', 'jpeg', 'jpg', 'tiff', 'webp']);
  });

  it('converts a PNG fixture to WebP', async () => {
    const inputPath = path.join(import.meta.dirname, '..', 'fixtures', 'sample.png');
    const outputPath = path.join(tmpDir, 'output.webp');
    const entry = resolve('png', 'webp');

    await entry.convert(inputPath, outputPath);

    const detected = await detectInputMime(outputPath);
    expect(detected.mime).toBe('image/webp');
  });

  it('converts a PNG fixture to JPG', async () => {
    const inputPath = path.join(import.meta.dirname, '..', 'fixtures', 'sample.png');
    const outputPath = path.join(tmpDir, 'output.jpg');
    const entry = resolve('png', 'jpg');

    await entry.convert(inputPath, outputPath);

    const detected = await detectInputMime(outputPath);
    expect(detected.mime).toBe('image/jpeg');
  });

  it('produces a smaller JPG at lower quality than at higher quality', async () => {
    const lowPath = path.join(tmpDir, 'low.jpg');
    const highPath = path.join(tmpDir, 'high.jpg');
    const entry = resolve('png', 'jpg');

    await entry.convert(noisyPngPath, lowPath, { quality: 10 });
    await entry.convert(noisyPngPath, highPath, { quality: 95 });

    const [lowStat, highStat] = await Promise.all([fs.stat(lowPath), fs.stat(highPath)]);
    expect(lowStat.size).toBeLessThan(highStat.size);
  });

  it('produces a smaller-or-equal PNG at a higher compressionLevel', async () => {
    const jpgPath = path.join(tmpDir, 'noisy.jpg');
    await sharp(noisyPngPath).jpeg({ quality: 90 }).toFile(jpgPath);

    const fastPath = path.join(tmpDir, 'fast.png');
    const slowPath = path.join(tmpDir, 'slow.png');
    const entry = resolve('jpg', 'png');

    await entry.convert(jpgPath, fastPath, { quality: 0 });
    await entry.convert(jpgPath, slowPath, { quality: 9 });

    const [fastStat, slowStat] = await Promise.all([fs.stat(fastPath), fs.stat(slowPath)]);
    expect(slowStat.size).toBeLessThanOrEqual(fastStat.size);
  });
});