import { describe, expect, it } from 'vitest';
import { dhashFromGray, hamming, hostRule, imageKey, nearestWidth, requestHeadersFor } from './images-core';

describe('images-core', () => {
  it('computes a stable dHash and hamming distance', () => {
    const grad = Array.from({ length: 72 }, (_, i) => (i % 9) * 30); // left→right ramp: all bits 0
    const h1 = dhashFromGray(grad);
    expect(h1).toBe('0000000000000000');
    const inv = Array.from({ length: 72 }, (_, i) => 255 - (i % 9) * 30);
    const h2 = dhashFromGray(inv);
    expect(h2).toBe('ffffffffffffffff');
    expect(hamming(h1, h2)).toBe(64);
    expect(hamming(h1, h1)).toBe(0);
  });

  it('applies host rules', () => {
    expect(hostRule('cards.scryfall.io').maxConcurrent).toBe(4);
    const h = requestHeadersFor(new URL('https://storage.googleapis.com/images.pricecharting.com/x/240.jpg'));
    expect(h.referer).toBe('https://www.pricecharting.com/');
    expect(h['user-agent']).toMatch(/RareIndexImageCache/);
    expect(h['user-agent']).not.toBe('node');
    const c = requestHeadersFor(new URL('https://www.comicconnect.com/coverimages/x.jpg'));
    expect(c.referer).toBe('https://www.comicconnect.com/');
    expect(requestHeadersFor(new URL('https://images.ygoprodeck.com/images/cards/1.jpg')).referer).toBeUndefined();
  });

  it('snaps widths and keys urls', () => {
    expect(nearestWidth(100)).toBe(192);
    expect(nearestWidth(384)).toBe(384);
    expect(nearestWidth(5000)).toBe(1200);
    expect(nearestWidth('abc')).toBe(384);
    expect(imageKey('https://a/b.jpg')).toHaveLength(40);
    expect(imageKey('https://a/b.jpg')).toBe(imageKey('https://a/b.jpg'));
  });
});