import { describe, it, expect, beforeEach, afterEach } from 'vitest';
import { MockAgent } from 'undici';
import { HttpFetcher } from './fetcher.js';

describe('HttpFetcher', () => {
  let mockAgent: MockAgent;
  let fetcher: HttpFetcher;

  beforeEach(() => {
    mockAgent = new MockAgent();
    mockAgent.disableNetConnect();
    fetcher = new HttpFetcher({ timeout: 5000, dispatcher: mockAgent });
  });

  afterEach(async () => {
    await mockAgent.close();
  });

  it('returns response for valid RSS feed', async () => {
    const mockPool = mockAgent.get('https://example.com');
    mockPool
      .intercept({ path: '/feed.xml', method: 'GET' })
      .reply(200, '<?xml version="1.0"?><rss></rss>', {
        headers: { 'content-type': 'application/rss+xml' },
      });

    const result = await fetcher.fetch({
      url: 'https://example.com/feed.xml',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(1);
    expect(result.errors).toHaveLength(0);
    expect(result.responses[0].body).toBe('<?xml version="1.0"?><rss></rss>');
    expect(result.responses[0].contentType).toBe('application/rss+xml');
    expect(result.responses[0].statusCode).toBe(200);
  });

  it('returns response for valid Atom feed', async () => {
    const mockPool = mockAgent.get('https://example.com');
    mockPool
      .intercept({ path: '/atom.xml', method: 'GET' })
      .reply(200, '<?xml version="1.0"?><feed></feed>', {
        headers: { 'content-type': 'application/atom+xml' },
      });

    const result = await fetcher.fetch({
      url: 'https://example.com/atom.xml',
      expectedFormat: 'atom',
    });

    expect(result.responses).toHaveLength(1);
    expect(result.errors).toHaveLength(0);
    expect(result.responses[0].body).toBe('<?xml version="1.0"?><feed></feed>');
  });

  it('returns PARSE error for wrong content type', async () => {
    const mockPool = mockAgent.get('https://example.com');
    mockPool
      .intercept({ path: '/feed.json', method: 'GET' })
      .reply(200, '{"foo":"bar"}', {
        headers: { 'content-type': 'application/json' },
      });

    const result = await fetcher.fetch({
      url: 'https://example.com/feed.json',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(0);
    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].code).toBe('PARSE');
    expect(result.errors[0].reason).toContain('Unexpected content type');
  });

  it('returns PARSE error when body does not look like XML', async () => {
    const mockPool = mockAgent.get('https://example.com');
    mockPool
      .intercept({ path: '/plain.txt', method: 'GET' })
      .reply(200, 'not xml at all', {
        headers: { 'content-type': 'text/plain' },
      });

    const result = await fetcher.fetch({
      url: 'https://example.com/plain.txt',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(0);
    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].code).toBe('PARSE');
  });

  it('returns UNKNOWN error for non-2xx status', async () => {
    const mockPool = mockAgent.get('https://example.com');
    mockPool
      .intercept({ path: '/notfound.xml', method: 'GET' })
      .reply(404, 'Not Found', {
        headers: { 'content-type': 'text/plain' },
      });

    const result = await fetcher.fetch({
      url: 'https://example.com/notfound.xml',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(0);
    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].code).toBe('UNKNOWN');
    expect(result.errors[0].reason).toContain('404');
  });

  it('returns NETWORK error for connection refused', async () => {
    const mockPool = mockAgent.get('https://offline.com');
    const networkError = new Error('connect ECONNREFUSED 127.0.0.1:443');
    mockPool.intercept({ path: '/feed.xml', method: 'GET' }).replyWithError(networkError);

    const result = await fetcher.fetch({
      url: 'https://offline.com/feed.xml',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(0);
    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].code).toBe('NETWORK');
  });

  it('returns TIMEOUT error for abort error', async () => {
    const mockPool = mockAgent.get('https://slow.com');
    const abortError = new Error('The operation was aborted');
    abortError.name = 'AbortError';
    mockPool.intercept({ path: '/feed.xml', method: 'GET' }).replyWithError(abortError);

    const result = await fetcher.fetch({
      url: 'https://slow.com/feed.xml',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(0);
    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].code).toBe('TIMEOUT');
  });

  it('uses body sniff fallback when content-type is missing', async () => {
    const mockPool = mockAgent.get('https://example.com');
    mockPool
      .intercept({ path: '/feed.xml', method: 'GET' })
      .reply(200, '<?xml version="1.0"?><rss></rss>', {
        headers: {},
      });

    const result = await fetcher.fetch({
      url: 'https://example.com/feed.xml',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(1);
    expect(result.errors).toHaveLength(0);
    expect(result.responses[0].contentType).toBe('application/xml');
  });

  it('accepts generic application/xml for RSS', async () => {
    const mockPool = mockAgent.get('https://example.com');
    mockPool
      .intercept({ path: '/feed.xml', method: 'GET' })
      .reply(200, '<?xml version="1.0"?><rss></rss>', {
        headers: { 'content-type': 'application/xml' },
      });

    const result = await fetcher.fetch({
      url: 'https://example.com/feed.xml',
      expectedFormat: 'rss',
    });

    expect(result.responses).toHaveLength(1);
    expect(result.errors).toHaveLength(0);
  });

  it('processes multiple feeds with mixed results via fetchMany', async () => {
    const okPool = mockAgent.get('https://ok.com');
    okPool
      .intercept({ path: '/feed.xml', method: 'GET' })
      .reply(200, '<?xml version="1.0"?><rss></rss>', {
        headers: { 'content-type': 'application/rss+xml' },
      });

    const failPool = mockAgent.get('https://fail.com');
    failPool
      .intercept({ path: '/feed.xml', method: 'GET' })
      .reply(500, 'Internal Server Error', {
        headers: { 'content-type': 'text/plain' },
      });

    const result = await fetcher.fetchMany([
      { url: 'https://ok.com/feed.xml', expectedFormat: 'rss' },
      { url: 'https://fail.com/feed.xml', expectedFormat: 'rss' },
    ]);

    expect(result.responses).toHaveLength(1);
    expect(result.errors).toHaveLength(1);
    expect(result.responses[0].source).toBe('https://ok.com/feed.xml');
    expect(result.errors[0].source).toBe('https://fail.com/feed.xml');
  });

  it('returns empty result for empty input array', async () => {
    const result = await fetcher.fetchMany([]);

    expect(result.responses).toHaveLength(0);
    expect(result.errors).toHaveLength(0);
  });
});