refactor: dedup buildTrackList, extract topsong row helper, split romaji to lib

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/novasonic-server.js

@@ -10,7 +10,6 @@
 
 const express      = require('express');
 const { execSync } = require('child_process');
-const { createHash } = require('crypto');
 const path         = require('path');
 const fs           = require('fs');
 const https        = require('https');
@@ -19,100 +18,7 @@ const CONFIG    = require('./lib/config');
 const { jobs, updateJob, log } = require('./lib/jobs');
 const { lookupItunesTrackMeta, fetchItunesTracks, searchItunesAlbumTracks } = require('./lib/metadata');
 const { downloadTrack, downloadAlbumTracks } = require('./lib/downloader');
-
-// ─── ROMAJI INDEX ─────────────────────────────────────────────────────────────
-// Converts kanji/kana → romaji so users can search Japanese songs phonetically.
-
-let _tokenizer = null;
-try {
-  const kuromoji = require('kuromoji');
-  const dicPath  = path.join(path.dirname(require.resolve('kuromoji')), '..', 'dict');
-  kuromoji.builder({ dicPath })
-    .build((err, t) => {
-      if (err) console.warn('⚠️  kuromoji failed to load:', err.message);
-      else     { _tokenizer = t; console.log('✅ kuromoji tokenizer ready'); }
-    });
-} catch { console.warn('⚠️  kuromoji not installed — run: cd backend && npm install'); }
-
-// katakana→hiragana shift (kuromoji readings come back in katakana)
-function _kataToHira(s) { return s.replace(/[ァ-ヶ]/g, c => String.fromCharCode(c.charCodeAt(0) - 0x60)); }
-
-// Full hiragana → romaji table (includes digraphs + っ doubling)
-const _H2R = {
-  'あ':'a','い':'i','う':'u','え':'e','お':'o',
-  'か':'ka','き':'ki','く':'ku','け':'ke','こ':'ko',
-  'さ':'sa','し':'shi','す':'su','せ':'se','そ':'so',
-  'た':'ta','ち':'chi','つ':'tsu','て':'te','と':'to',
-  'な':'na','に':'ni','ぬ':'nu','ね':'ne','の':'no',
-  'は':'ha','ひ':'hi','ふ':'fu','へ':'he','ほ':'ho',
-  'ま':'ma','み':'mi','む':'mu','め':'me','も':'mo',
-  'や':'ya','ゆ':'yu','よ':'yo',
-  'ら':'ra','り':'ri','る':'ru','れ':'re','ろ':'ro',
-  'わ':'wa','を':'wo','ん':'n',
-  'が':'ga','ぎ':'gi','ぐ':'gu','げ':'ge','ご':'go',
-  'ざ':'za','じ':'ji','ず':'zu','ぜ':'ze','ぞ':'zo',
-  'だ':'da','ぢ':'di','づ':'du','で':'de','ど':'do',
-  'ば':'ba','び':'bi','ぶ':'bu','べ':'be','ぼ':'bo',
-  'ぱ':'pa','ぴ':'pi','ぷ':'pu','ぺ':'pe','ぽ':'po',
-  'きゃ':'kya','きゅ':'kyu','きょ':'kyo',
-  'しゃ':'sha','しゅ':'shu','しょ':'sho',
-  'ちゃ':'cha','ちゅ':'chu','ちょ':'cho',
-  'にゃ':'nya','にゅ':'nyu','にょ':'nyo',
-  'ひゃ':'hya','ひゅ':'hyu','ひょ':'hyo',
-  'みゃ':'mya','みゅ':'myu','みょ':'myo',
-  'りゃ':'rya','りゅ':'ryu','りょ':'ryo',
-  'ぎゃ':'gya','ぎゅ':'gyu','ぎょ':'gyo',
-  'じゃ':'ja','じゅ':'ju','じょ':'jo',
-  'びゃ':'bya','びゅ':'byu','びょ':'byo',
-  'ぴゃ':'pya','ぴゅ':'pyu','ぴょ':'pyo',
-  'ふぁ':'fa','ふぃ':'fi','ふぇ':'fe','ふぉ':'fo',
-  'てぃ':'ti','でぃ':'di','とぅ':'tu','どぅ':'du',
-  'ゐ':'i','ゑ':'e','ヴ':'vu',
-};
-function _hiraToRomaji(str) {
-  let out = '', i = 0;
-  while (i < str.length) {
-    if (str[i] === 'っ') {
-      const nxt = _H2R[str.slice(i+1,i+3)] || _H2R[str[i+1]] || '';
-      out += nxt[0] || ''; i++; continue;
-    }
-    const two = _H2R[str.slice(i,i+2)];
-    if (two) { out += two; i += 2; continue; }
-    out += _H2R[str[i]] ?? str[i]; i++;
-  }
-  return out;
-}
-
-const JP_RE = /[぀-ヿ㐀-䶿一-鿿＀-￯]/;
-function _toRomaji(text) {
-  if (!text || !_tokenizer || !JP_RE.test(text)) return text || '';
-  const tokens = _tokenizer.tokenize(text);
-  const hira = tokens.map(t => {
-    const r = t.reading;
-    return (r && r !== '*') ? _kataToHira(r) : t.surface_form;
-  }).join('');
-  return _hiraToRomaji(hira).toLowerCase();
-}
-
-// Cache: key = "ndUrl|user" → { ts, index }
-const _romajiCache = new Map();
-const ROMAJI_TTL   = 20 * 60 * 1000; // 20 min
-
-async function _fetchNdSongs(ndUrl, user, pass) {
-  const salt  = Math.random().toString(36).slice(2, 10);
-  const token = createHash('md5').update(pass + salt).digest('hex');
-  const base  = `${ndUrl}/rest/search3.view?u=${encodeURIComponent(user)}&t=${token}&s=${salt}&v=1.16.1&c=novasonic&f=json&albumCount=0&artistCount=0`;
-  const songs = [];
-  let offset = 0;
-  while (true) {
-    const r    = await fetch(`${base}&query=&songCount=500&songOffset=${offset}`).then(r => r.json());
-    const page = r['subsonic-response']?.searchResult3?.song || [];
-    songs.push(...page);
-    if (page.length < 500) break;
-    offset += 500;
-  }
-  return songs;
-}
+const { buildRomajiIndex, clearRomajiCache, isTokenizerReady } = require('./lib/romaji');
 
 // ─── INIT ─────────────────────────────────────────────────────────────────────
 const app = express();
@@ -169,29 +75,10 @@ function parseSpotifyUrl(url) {
 app.get('/api/romaji-index', async (req, res) => {
   const { ndUrl, user, pass } = req.query;
   if (!ndUrl || !user || !pass) return res.status(400).json({ error: 'missing params' });
-  if (!_tokenizer) return res.status(503).json({ error: 'tokenizer not ready — try again in a few seconds' });
-
-  const key    = `${ndUrl}|${user}`;
-  const cached = _romajiCache.get(key);
-  if (cached && Date.now() - cached.ts < ROMAJI_TTL) return res.json(cached.index);
-
+  if (!isTokenizerReady()) return res.status(503).json({ error: 'tokenizer not ready — try again in a few seconds' });
   try {
-    const songs = await _fetchNdSongs(ndUrl, user, pass);
-    const index = songs
-      .filter(s => JP_RE.test(s.title) || JP_RE.test(s.artist) || JP_RE.test(s.album))
-      .map(s => ({
-        id:       s.id,
-        r:        [_toRomaji(s.title), _toRomaji(s.artist), _toRomaji(s.album)].join(' '),
-        title:    s.title,
-        artist:   s.artist    || '',
-        album:    s.album     || '',
-        coverArt: s.coverArt  || '',
-        duration: s.duration  || 0,
-        albumId:  s.albumId   || '',
-        artistId: s.artistId  || '',
-      }));
-    _romajiCache.set(key, { ts: Date.now(), index });
-    console.log(`✅ Romaji index built: ${index.length} JP songs (${songs.length} total)`);
+    const { fromCache, index } = await buildRomajiIndex(ndUrl, user, pass);
+    if (!fromCache) console.log(`✅ Romaji index built: ${index.length} JP songs`);
     res.json(index);
   } catch (e) {
     console.error('Romaji index error:', e);
@@ -201,7 +88,7 @@ app.get('/api/romaji-index', async (req, res) => {
 
 // DELETE /api/romaji-index — force rebuild on next request
 app.delete('/api/romaji-index', (req, res) => {
-  _romajiCache.clear();
+  clearRomajiCache();
   res.json({ ok: true });
 });