import { describe, it, expect } from 'vitest';
import sharp from 'sharp';
import { preprocessImage } from '../../src/lib/server/ai/image-preprocess';

async function makeTestImage(
  width: number,
  height: number,
  format: 'jpeg' | 'png' | 'webp' = 'jpeg'
): Promise<Buffer> {
  return sharp({
    create: {
      width,
      height,
      channels: 3,
      background: { r: 128, g: 128, b: 128 }
    }
  })
    .toFormat(format)
    .toBuffer();
}

describe('preprocessImage', () => {
  it('resizes a landscape image so long edge <= 1600px', async () => {
    const input = await makeTestImage(4000, 2000);
    const { buffer, mimeType } = await preprocessImage(input);
    const meta = await sharp(buffer).metadata();
    expect(Math.max(meta.width ?? 0, meta.height ?? 0)).toBeLessThanOrEqual(1600);
    expect(Math.max(meta.width ?? 0, meta.height ?? 0)).toBeGreaterThan(1000);
    expect(mimeType).toBe('image/jpeg');
  });

  it('resizes a portrait image so long edge <= 1600px', async () => {
    const input = await makeTestImage(2000, 4000);
    const { buffer } = await preprocessImage(input);
    const meta = await sharp(buffer).metadata();
    expect(Math.max(meta.width ?? 0, meta.height ?? 0)).toBeLessThanOrEqual(1600);
  });

  it('does not upscale smaller images', async () => {
    const input = await makeTestImage(800, 600);
    const { buffer } = await preprocessImage(input);
    const meta = await sharp(buffer).metadata();
    expect(meta.width).toBe(800);
    expect(meta.height).toBe(600);
  });

  it('converts PNG input to JPEG output', async () => {
    const input = await makeTestImage(1000, 1000, 'png');
    const { buffer, mimeType } = await preprocessImage(input);
    const meta = await sharp(buffer).metadata();
    expect(meta.format).toBe('jpeg');
    expect(mimeType).toBe('image/jpeg');
  });

  it('strips EXIF metadata', async () => {
    const input = await sharp({
      create: { width: 100, height: 100, channels: 3, background: '#888' }
    })
      .withMetadata({ exif: { IFD0: { Copyright: 'test' } } })
      .jpeg()
      .toBuffer();
    const { buffer } = await preprocessImage(input);
    const meta = await sharp(buffer).metadata();
    expect(meta.exif).toBeUndefined();
  });

  it('rejects non-image buffers', async () => {
    const notAnImage = Buffer.from('hello world');
    await expect(preprocessImage(notAnImage)).rejects.toThrow();
  });
});