// Step 16 — Transcript tests (offline fixtures for parsers + API contract).
// Run with: npm run test:transcript
import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import fs from 'node:fs';
import path from 'node:path';
import os from 'node:os';
import { spawn } from 'node:child_process';
import net from 'node:net';
import {
  pickTrack,
  parseJson3,
  parseVtt,
  parseTrackText,
  parseXmlCaptions,
  dedupeTranscriptLines,
  orderedTracks,
  translatedFallbacks,
  firstPerLanguage,
  looksLikeHtmlError,
  capLines,
  normalizeTranscriptProvider,
} from '../transcript.mjs';

const track = (url, ext = 'vtt') => ({ url, ext });

describe('pickTrack', () => {
  it('prefers manual subtitles over automatic captions', () => {
    const json = {
      subtitles: { en: [track('https://x/en.vtt')] },
      automatic_captions: { en: [track('https://x/en.auto.vtt')] },
    };
    const { track: t, lang } = pickTrack(json, 'en');
    assert.equal(t.url, 'https://x/en.vtt');
    assert.equal(lang, 'en');
  });

  it('falls back fr -> fr-* -> auto -> first available', () => {
    const json = {
      subtitles: { 'fr-CA': [track('https://x/frca.vtt')] },
      automatic_captions: { en: [track('https://x/en.auto.vtt')] },
    };
    assert.equal(pickTrack(json, 'fr').lang, 'fr-CA');
    // 'de' matches nothing: first available (manual preferred)
    const fb = pickTrack(json, 'de');
    assert.equal(fb.lang, 'fr-CA');
    // auto-only dict
    const autoOnly = pickTrack({ automatic_captions: { en: [track('https://x/e.vtt')] } }, 'en');
    assert.equal(autoOnly.track.url, 'https://x/e.vtt');
  });

  it('returns null track when no subtitles exist', () => {
    assert.deepEqual(pickTrack({}, 'fr'), { track: null, languages: [], lang: null });
    assert.deepEqual(pickTrack({ subtitles: {}, automatic_captions: {} }, 'en'), {
      track: null,
      languages: [],
      lang: null,
    });
  });

  it('exposes the language list for the UI selector', () => {
    const { languages } = pickTrack(
      { subtitles: { fr: [track('a')], en: [track('b')] }, automatic_captions: { es: [track('c')] } },
      'fr',
    );
    assert.deepEqual([...languages].sort(), ['en', 'es', 'fr']);
  });
});

describe('parseJson3', () => {
  it('converts events with segs to normalized lines', () => {
    const lines = parseJson3({
      events: [
        { tStartMs: 0, dDurationMs: 2500, segs: [{ utf8: 'Bonjour' }] },
        { tStartMs: 2500, dDurationMs: 3100, segs: [{ utf8: 'Bien' }, { utf8: 'venue' }] },
      ],
    });
    assert.deepEqual(lines, [
      { t: 0, dur: 2.5, text: 'Bonjour' },
      { t: 2.5, dur: 3.1, text: 'Bienvenue' },
    ]);
  });

  it('drops events without segs or with empty text', () => {
    const lines = parseJson3({ events: [{ tStartMs: 0 }, { tStartMs: 1, dDurationMs: 1, segs: [{ utf8: '   ' }] }] });
    assert.deepEqual(lines, []);
    assert.deepEqual(parseJson3({}), []);
  });
});

describe('parseVtt', () => {
  const vtt = `WEBVTT

00:00:00.000 --> 00:00:02.500
Bonjour <c.colorE5E5E5>à tous</c>

12
00:00:02.500 --> 00:00:05.600
Bienvenue
dans cette vidéo
`;
  it('parses cues with identifiers, tags and multi-line content', () => {
    const lines = parseVtt(vtt);
    assert.equal(lines.length, 2);
    assert.equal(lines[0].t, 0);
    assert.equal(lines[0].dur, 2.5);
    assert.equal(lines[0].text, 'Bonjour à tous');
    assert.equal(lines[1].text, 'Bienvenue dans cette vidéo');
    assert.ok(Math.abs(lines[1].t - 2.5) < 1e-9);
  });

  it('supports MM:SS.mmm timestamps and decodes entities', () => {
    const lines = parseVtt('WEBVTT\n\n01:02.000 --> 01:04.500\nFish &amp; chips\n');
    assert.equal(lines.length, 1);
    assert.equal(lines[0].t, 62);
    assert.equal(lines[0].text, 'Fish & chips');
  });

  it('ignores garbage blocks', () => {
    assert.deepEqual(parseVtt('WEBVTT\n\nNOTE nothing here\n'), []);
  });
});

describe('orderedTracks + parseTrackText + XML captions', () => {
  const auto = {
    fr: [{ url: 'https://x/fr.json3', ext: 'json3' }],
    en: [{ url: 'https://x/en.json3', ext: 'json3' }],
    es: [{ url: 'https://x/es.vtt', ext: 'vtt' }],
  };
  it('tries requested lang first, then original en', () => {
    const langs = orderedTracks({ subtitles: {}, automatic_captions: auto }, 'fr').map((o) => o.lang);
    assert.deepEqual(langs, ['fr', 'en', 'es']);
  });
  it('dedupes identical track URLs', () => {
    const dup = { subtitles: {}, automatic_captions: { en: [{ url: 'https://x/same', ext: 'vtt' }], fr: [{ url: 'https://x/same', ext: 'vtt' }] } };
    assert.equal(orderedTracks(dup, 'fr').length, 1);
  });
  it('detects HTML error pages instead of JSON-parsing them', () => {
    assert.equal(looksLikeHtmlError('<!DOCTYPE html><html>Sorry</html>'), true);
    assert.equal(looksLikeHtmlError('WEBVTT\n\n00:00:00.000 --> 1'), false);
    assert.deepEqual(parseTrackText('<!DOCTYPE html> nope', 'json3'), []);
  });
  it('parses srv/ttml XML captions', () => {
    const srv = parseXmlCaptions('<transcript><p t="0" d="2500">Hello</p></transcript>');
    assert.equal(srv.length, 1);
    assert.equal(srv[0].text, 'Hello');
    const ttml = parseXmlCaptions('<tt><body><div><p begin="00:00:01.000" end="00:00:03.500">Bonjour</p></div></body></tt>');
    assert.equal(ttml.length, 1);
    assert.equal(ttml[0].t, 1);
  });
  it('parseTrackText handles json3 and vtt payloads', () => {
    const j = parseTrackText(JSON.stringify({ events: [{ tStartMs: 0, dDurationMs: 1000, segs: [{ utf8: 'Hi' }] }] }), 'json3');
    assert.equal(j.length, 1);
    const v = parseTrackText('WEBVTT\n\n00:00:00.000 --> 00:00:01.000\nHello\n', 'vtt');
    assert.equal(v.length, 1);
  });
  it('translatedFallbacks appends &tlang= candidates from other languages only', () => {    const cands = [
      { track: { url: 'https://x/t?lang=en-US', ext: 'json3' }, lang: 'en-us' },
      { track: { url: 'https://x/t?lang=fr', ext: 'json3' }, lang: 'fr' },
    ];
    const t = translatedFallbacks(cands, 'en');
    assert.equal(t.length, 1);
    assert.equal(t[0].lang, 'en');
    assert.match(t[0].track.url, /tlang=en/);
    // Same primary language sources are skipped, not re-translated.
    assert.equal(translatedFallbacks(cands, 'fr').length, 1);
    assert.equal(translatedFallbacks(cands, '').length, 0);
  });
  it('firstPerLanguage keeps one candidate per language in order, bounded', () => {
    const cands = [
      { track: { url: 'https://x/a' }, lang: 'en-US' },
      { track: { url: 'https://x/b' }, lang: 'en' },
      { track: { url: 'https://x/c' }, lang: 'fr' },
      { track: { url: 'https://x/d' }, lang: null },
    ];
    const out = firstPerLanguage(cands, 10).map((c) => c.track.url);
    assert.deepEqual(out, ['https://x/a', 'https://x/c', 'https://x/d']);
    assert.equal(firstPerLanguage(cands, 2).length, 2);
  });
});

describe('dedupeTranscriptLines (rolling-window auto-captions)', () => {
  it('collapses prefix extensions and exact duplicates', () => {
    const lines = dedupeTranscriptLines([
      { t: 0, dur: 1, text: 'Tac.' },
      { t: 1, dur: 1, text: 'Tac.' },
      { t: 1, dur: 2, text: 'Tac. David Prou est avec nous. David,' },
      { t: 2, dur: 1, text: 'David Prou est avec nous. David,' },
      { t: 2, dur: 2, text: 'David Prou est avec nous. David, bonjour.' },
      { t: 3, dur: 1, text: 'bonjour.' },
      { t: 3, dur: 2, text: 'bonjour. Bonjour Benois.' },
    ]);
    assert.ok(lines.length < 7, `expected fewer lines, got ${lines.length}`);
    assert.ok(lines.length >= 1);
    const joined = lines.map((l) => l.text).join(' ');
    assert.match(joined, /David Prou/);
    assert.match(joined, /Benois/);
    // No word lost, no exact consecutive duplicates remain.
    for (let i = 1; i < lines.length; i++) {
      assert.notEqual(lines[i].text.trim().toLowerCase(), lines[i - 1].text.trim().toLowerCase());
    }
  });

  it('merges sliding partial overlaps without fragments', () => {
    const lines = dedupeTranscriptLines([
      { t: 6, dur: 2, text: "Alors ce roman québécois c'était ça ou" },
      { t: 6, dur: 2, text: "Alors ce roman québécois c'était ça ou mourir ?" },
      { t: 7, dur: 1, text: 'mourir ?' },
    ]);
    assert.equal(lines.length, 1);
    assert.match(lines[0].text, /mourir/);
  });

  it('parseJson3 dedupes rolling events end-to-end', () => {
    const lines = parseJson3({
      events: [
        { tStartMs: 0, dDurationMs: 1000, segs: [{ utf8: 'Tac.' }] },
        { tStartMs: 1000, dDurationMs: 1000, segs: [{ utf8: 'Tac.' }] },
        { tStartMs: 1000, dDurationMs: 2000, segs: [{ utf8: 'Tac. David Prou est avec nous.' }] },
        { tStartMs: 2000, dDurationMs: 1000, segs: [{ utf8: 'David Prou est avec nous.' }] },
      ],
    });
    assert.equal(lines.length, 1);
    assert.match(lines[0].text, /David Prou/);
  });

  it('keeps distinct sentences on separate cues', () => {
    const lines = dedupeTranscriptLines([
      { t: 0, dur: 2, text: 'Bonjour à tous.' },
      { t: 10, dur: 2, text: 'On parle intelligence artificielle.' },
      { t: 20, dur: 2, text: 'Merci beaucoup.' },
    ]);
    assert.equal(lines.length, 3);
  });
});

describe('capLines + normalizeTranscriptProvider', () => {  it('truncates very long transcripts', () => {
    const lines = Array.from({ length: 10 }, (_, i) => ({ t: i, dur: 1, text: `l${i}` }));
    assert.equal(capLines(lines, 3).length, 3);
  });
  it('maps short and long provider ids', () => {
    assert.equal(normalizeTranscriptProvider('yt'), 'youtube');
    assert.equal(normalizeTranscriptProvider('youtube'), 'youtube');
    assert.equal(normalizeTranscriptProvider('dm'), 'dailymotion');
    assert.equal(normalizeTranscriptProvider('pt'), 'peertube');
    assert.equal(normalizeTranscriptProvider('xx'), null);
  });
});

describe('API contract', () => {
  it('rejects unknown providers with 400 { available: false }', async () => {
    const port = await new Promise((resolve) => {
      const srv = net.createServer();
      srv.listen(0, '127.0.0.1', () => {
        const p = srv.address().port;
        srv.close(() => resolve(p));
      });
    });
    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'newtube-transcript-test-'));
    const server = spawn(process.execPath, ['./server/index.mjs'], {
      env: {
        ...process.env,
        PORT: String(port),
        NEWTUBE_DB_FILE: path.join(tmpDir, 'transcript.db'),
        JWT_SECRET: 'transcript-test-secret',
        NODE_ENV: 'test',
      },
      stdio: ['ignore', 'pipe', 'pipe'],
      cwd: path.resolve(import.meta.dirname, '..', '..'),
    });
    const baseUrl = `http://127.0.0.1:${port}`;
    const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
    try {
      let up = false;
      const start = Date.now();
      while (Date.now() - start < 20000) {
        try {
          const res = await fetch(`${baseUrl}/`);
          if (res.status < 500) { up = true; break; }
        } catch {}
        await sleep(300);
      }
      assert.ok(up, 'isolated server starts');
      const res = await fetch(`${baseUrl}/api/transcript/xx/abc123?lang=fr`);
      assert.equal(res.status, 400);
      const body = await res.json();
      assert.equal(body.available, false);
      assert.ok(typeof body.error === 'string');
    } finally {
      server.kill();
    }
  });
});