// Copyright (c) 2026 Gordon Bolton. MIT License.
/**
 * Tests for server/utils/qbittorrent.js pure utility functions.
 *
 * mapTorrentToDownload, formatBytes, formatSpeed, and formatEta are all
 * pure functions with no I/O — ideal unit test targets. These power the
 * dashboard card rendering so correctness matters for UX.
 */

import { mapTorrentToDownload, formatBytes, formatSpeed, formatEta } from '../../server/utils/qbittorrent.js';
import QBittorrentClient from '../../server/clients/QBittorrentClient.js';
import nock from 'nock';

// Minimal torrent fixture that satisfies mapTorrentToDownload's expectations
function makeTorrent(overrides = {}) {
  return {
    name: 'My.Show.S01E01.1080p.mkv',
    state: 'downloading',
    size: 1073741824,        // 1 GB
    completed: 536870912,    // 512 MB
    progress: 0.5,
    dlspeed: 1048576,        // 1 MB/s
    eta: 512,                // seconds
    num_seeds: 10,
    num_leechs: 3,
    availability: 1.0,
    hash: 'aabbccdd',
    category: 'sonarr',
    tags: '',
    content_path: '/downloads/My.Show.S01E01.1080p.mkv',
    save_path: '/downloads/',
    instanceName: 'i3omb',
    ...overrides
  };
}

const QBT_URL = 'http://qbittorrent.test:8080';

function makeClient(overrides = {}) {
  return new QBittorrentClient({
    id: 'test-qbt',
    name: 'TestQBT',
    url: QBT_URL,
    username: 'admin',
    password: 'adminadmin',
    ...overrides
  });
}

function mockLogin() {
  return nock(QBT_URL)
    .post('/api/v2/auth/login')
    .reply(200, {}, { 'set-cookie': ['SID=abc123; path=/'] });
}

function mockSync(rid, response) {
  return nock(QBT_URL)
    .get(`/api/v2/sync/maindata?rid=${rid}`)
    .reply(200, response);
}

afterEach(() => {
  nock.cleanAll();
});

describe('formatBytes', () => {
  it('formats 0 bytes', () => expect(formatBytes(0)).toBe('0 B'));
  it('formats bytes', () => expect(formatBytes(512)).toBe('512 B'));
  it('formats kilobytes', () => expect(formatBytes(1024)).toBe('1 KB'));
  it('formats megabytes', () => expect(formatBytes(1048576)).toBe('1 MB'));
  it('formats gigabytes', () => expect(formatBytes(1073741824)).toBe('1 GB'));
  it('formats fractional GB', () => expect(formatBytes(1610612736)).toBe('1.5 GB'));
});

describe('formatSpeed', () => {
  it('appends /s to byte count', () => expect(formatSpeed(1048576)).toBe('1 MB/s'));
  it('handles zero speed', () => expect(formatSpeed(0)).toBe('0 B/s'));
});

describe('formatEta', () => {
  it('returns ∞ for qBittorrent unknown sentinel (8640000)', () => {
    expect(formatEta(8640000)).toBe('∞');
  });
  it('returns ∞ for negative eta', () => expect(formatEta(-1)).toBe('∞'));
  it('formats minutes only', () => expect(formatEta(90)).toBe('1m'));
  it('formats hours and minutes', () => expect(formatEta(3661)).toBe('1h 1m'));
  it('formats days, hours and minutes', () => expect(formatEta(90061)).toBe('1d 1h 1m'));
  it('returns 0m for zero seconds', () => expect(formatEta(0)).toBe('0m'));
});

describe('mapTorrentToDownload', () => {
  it('maps a downloading torrent correctly', () => {
    const result = mapTorrentToDownload(makeTorrent());
    expect(result.status).toBe('Downloading');
    expect(result.progress).toBe('50.0');
    expect(result.size).toBe('1 GB');
    expect(result.speed).toBe('1 MB/s');
    expect(result.eta).toBe('8m');
    expect(result.seeds).toBe(10);
    expect(result.peers).toBe(3);
    expect(result.qbittorrent).toBe(true);
    expect(result.instanceName).toBe('i3omb');
  });

  it('maps state: stalledDL → Downloading', () => {
    expect(mapTorrentToDownload(makeTorrent({ state: 'stalledDL' })).status).toBe('Downloading');
  });

  it('maps state: uploading → Seeding', () => {
    expect(mapTorrentToDownload(makeTorrent({ state: 'uploading' })).status).toBe('Seeding');
  });

  it('maps state: pausedDL → Paused', () => {
    expect(mapTorrentToDownload(makeTorrent({ state: 'pausedDL' })).status).toBe('Paused');
  });

  it('maps state: stoppedUP → Stopped', () => {
    expect(mapTorrentToDownload(makeTorrent({ state: 'stoppedUP' })).status).toBe('Stopped');
  });

  it('maps state: error → Error', () => {
    expect(mapTorrentToDownload(makeTorrent({ state: 'error' })).status).toBe('Error');
  });

  it('passes through unknown state verbatim', () => {
    expect(mapTorrentToDownload(makeTorrent({ state: 'weirdState' })).status).toBe('weirdState');
  });

  it('computes 100% progress for completed torrent', () => {
    const result = mapTorrentToDownload(makeTorrent({ progress: 1.0 }));
    expect(result.progress).toBe('100.0');
  });

  it('uses content_path as savePath when present', () => {
    const result = mapTorrentToDownload(makeTorrent({ content_path: '/dl/file.mkv' }));
    expect(result.savePath).toBe('/dl/file.mkv');
  });

  it('falls back to save_path when content_path is absent', () => {
    const result = mapTorrentToDownload(makeTorrent({ content_path: null, save_path: '/dl/' }));
    expect(result.savePath).toBe('/dl/');
  });
});

describe('QBittorrentClient sync API', () => {
  it('first call uses rid=0 and returns full torrent list', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    mockSync(0, {
      rid: 1,
      full_update: true,
      torrents: {
        hash01: { name: 'Test1', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
      }
    });

    const torrents = await client.getActiveDownloads();
    expect(torrents).toHaveLength(1);
    expect(torrents[0].title).toBe('Test1');
    expect(torrents[0].instanceId).toBe('test-qbt');
    expect(torrents[0].id).toBe('hash01');
    expect(client.lastRid).toBe(1);
  });

  it('subsequent call uses last rid and merges delta', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    // First call
    mockSync(0, {
      rid: 1,
      full_update: true,
      torrents: {
        hash01: { name: 'Test1', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
      }
    });
    await client.getActiveDownloads();

    // Second call — delta
    mockSync(1, {
      rid: 2,
      full_update: false,
      torrents: {
        hash01: { dlspeed: 200 }
      }
    });

    const torrents = await client.getActiveDownloads();
    expect(torrents).toHaveLength(1);
    expect(torrents[0].speed).toBe(200);
    expect(torrents[0].title).toBe('Test1');
    expect(client.lastRid).toBe(2);
  });

  it('handles full_update=true on subsequent call', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    // First call
    mockSync(0, {
      rid: 1,
      full_update: true,
      torrents: {
        hash01: { name: 'Test1', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
      }
    });
    await client.getActiveDownloads();

    // Server forces full refresh
    mockSync(1, {
      rid: 2,
      full_update: true,
      torrents: {
        hash02: { name: 'Test2', state: 'uploading', size: 2000, progress: 1.0, dlspeed: 0, eta: 0, num_seeds: 10, num_leechs: 0, availability: 1.0 }
      }
    });

    const torrents = await client.getActiveDownloads();
    expect(torrents).toHaveLength(1);
    expect(torrents[0].title).toBe('Test2');
    expect(torrents[0].id).toBe('hash02');
    expect(client.lastRid).toBe(2);
  });

  it('removes torrents when torrents_removed is present', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    mockSync(0, {
      rid: 1,
      full_update: true,
      torrents: {
        hash01: { name: 'Test1', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
      }
    });
    await client.getActiveDownloads();

    mockSync(1, {
      rid: 2,
      full_update: false,
      torrents_removed: ['hash01']
    });

    const torrents = await client.getActiveDownloads();
    expect(torrents).toHaveLength(0);
  });

  it('falls back to torrents/info when sync fails', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    // Sync fails with 500
    nock(QBT_URL)
      .get('/api/v2/sync/maindata?rid=0')
      .reply(500, { error: 'Internal Server Error' });

    // Legacy succeeds
    nock(QBT_URL)
      .get('/api/v2/torrents/info')
      .reply(200, [
        { name: 'Fallback', hash: 'fb01', state: 'downloading', size: 1073741824, progress: 0.5, dlspeed: 1048576, eta: 512, num_seeds: 10, num_leechs: 3, availability: 1.0 }
      ]);

    const torrents = await client.getActiveDownloads();
    expect(torrents).toHaveLength(1);
    expect(torrents[0].title).toBe('Fallback');
    expect(client.fallbackThisCycle).toBe(true);
  });

  it('uses legacy immediately if already fell back this cycle', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    client.fallbackThisCycle = true;

    // Only legacy should be called
    nock(QBT_URL)
      .get('/api/v2/torrents/info')
      .reply(200, [
        { name: 'DirectLegacy', hash: 'dl01', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
      ]);

    // Ensure sync is NOT called
    const syncScope = nock(QBT_URL)
      .get('/api/v2/sync/maindata?rid=0')
      .reply(200, { rid: 1, full_update: true });

    const torrents = await client.getActiveDownloads();
    expect(torrents).toHaveLength(1);
    expect(torrents[0].title).toBe('DirectLegacy');
    expect(syncScope.isDone()).toBe(false);
  });

  it('re-authenticates on 403 during sync and retries', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    // First sync call returns 403
    nock(QBT_URL)
      .get('/api/v2/sync/maindata?rid=0')
      .reply(403, {});

    // Re-login
    nock(QBT_URL)
      .post('/api/v2/auth/login')
      .reply(200, {}, { 'set-cookie': ['SID=newtoken; path=/'] });

    // Retry succeeds
    nock(QBT_URL)
      .get('/api/v2/sync/maindata?rid=0')
      .reply(200, {
        rid: 1,
        full_update: true,
        torrents: {
          hash01: { name: 'AfterReauth', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
        }
      });

    const torrents = await client.getActiveDownloads();
    expect(torrents).toHaveLength(1);
    expect(torrents[0].title).toBe('AfterReauth');
  });

  it('computes completed from size and progress when missing', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();

    mockSync(0, {
      rid: 1,
      full_update: true,
      torrents: {
        hash01: { name: 'NoCompleted', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
      }
    });

    const torrents = await client.getActiveDownloads();
    expect(torrents[0].downloaded).toBe(500);
  });

  it('resets fallback flag when getAllTorrents resets it', async () => {
    mockLogin();
    const client = makeClient();
    await client.login();
    client.fallbackThisCycle = true;

    // After reset, sync should be attempted
    mockSync(0, {
      rid: 1,
      full_update: true,
      torrents: {
        hash01: { name: 'ResetWorks', state: 'downloading', size: 1000, progress: 0.5, dlspeed: 100, eta: 60, num_seeds: 5, num_leechs: 2, availability: 1.0 }
      }
    });

    // Simulate the reset that getAllTorrents performs
    client.fallbackThisCycle = false;
    const torrents = await client.getActiveDownloads();
    expect(torrents[0].title).toBe('ResetWorks');
    expect(client.fallbackThisCycle).toBe(false);
  });
});