// Proxy for licensed translations (NLT, CSB, NASB) served by api.bible.
// The API key stays on the server (API_BIBLE_KEY, loaded from .env if present);
// the browser only ever talks to /api/bible/...
import { existsSync, readFileSync } from 'fs';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';

const __dirname = dirname(fileURLToPath(import.meta.url));

// Minimal .env loader so the key doesn't have to be exported in every launcher
// (setup.sh, systemd, docker). Real environment variables win.
const envPath = join(__dirname, '..', '.env');
if (existsSync(envPath)) {
  for (const line of readFileSync(envPath, 'utf8').split('\n')) {
    const m = line.match(/^\s*([A-Za-z_][A-Za-z0-9_]*)\s*=\s*(.*?)\s*$/);
    if (m && process.env[m[1]] === undefined) process.env[m[1]] = m[2].replace(/^(['"])(.*)\1$/, '$2');
  }
}

const API_BASE = 'https://rest.api.bible/v1';

// Canonical book order (index + 1 = the book number the ESV API uses in ranges).
const BOOK_ORDER = ['GEN','EXO','LEV','NUM','DEU','JOS','JDG','RUT','1SA','2SA','1KI','2KI','1CH','2CH','EZR','NEH','EST','JOB','PSA','PRO','ECC','SNG','ISA','JER','LAM','EZK','DAN','HOS','JOL','AMO','OBA','JON','MIC','NAM','HAB','ZEP','HAG','ZEC','MAL','MAT','MRK','LUK','JHN','ACT','ROM','1CO','2CO','GAL','EPH','PHP','COL','1TH','2TH','1TI','2TI','TIT','PHM','HEB','JAS','1PE','2PE','1JN','2JN','3JN','JUD','REV'];

export const LICENSED_TRANSLATIONS = {
  ESV: { provider: 'esv', name: 'English Standard Version' },
  NLT: { provider: 'api.bible', bibleId: 'd6e14a625393b4da-01', name: 'New Living Translation' },
  CSB: { provider: 'api.bible', bibleId: 'a556c5305ee15c3f-01', name: 'Christian Standard Bible' },
  NASB: { provider: 'api.bible', bibleId: 'b8ee27bcd1cae43a-01', name: 'New American Standard Bible (1995)' },
};

const CACHE_TTL = 24 * 60 * 60 * 1000;
const CACHE_MAX = 1000;
// Crossway limits how much ESV text an app may store, so ESV chapters are only
// held briefly and in small numbers (enough to absorb repeat loads).
const ESV_CACHE_TTL = 60 * 60 * 1000;
const ESV_CACHE_MAX = 20;
const cache = new Map(); // "NLT/PSA/23" -> { at, payload }

// api.bible returns plain text with inline "[12]" verse markers, poetry line
// breaks, and stray "#" / nbsp characters. Split it back into { number, text }.
export function parseChapterText(content) {
  const clean = String(content ?? '')
    .replace(/ /g, ' ')
    .replace(/#/g, '');
  const parts = clean.split(/\[(\d+)\]/);
  const verses = [];
  for (let i = 1; i < parts.length; i += 2) {
    const text = parts[i + 1].replace(/\s+/g, ' ').replace(/\s+,$/, '').trim();
    if (text) verses.push({ number: Number(parts[i]), text });
  }
  return verses;
}

export function registerBibleRoutes(app, requireAuth) {
  app.get('/api/bible/translations', requireAuth, (_req, res) => {
    res.json(Object.entries(LICENSED_TRANSLATIONS).map(([id, t]) => ({
      id, name: t.name, available: Boolean(t.provider === 'esv' ? process.env.ESV_API_KEY : process.env.API_BIBLE_KEY),
    })));
  });

  app.get('/api/bible/:translation/:book/:chapter', requireAuth, async (req, res) => {
    const translation = LICENSED_TRANSLATIONS[req.params.translation.toUpperCase()];
    const { book, chapter } = req.params;
    if (!translation) return res.status(404).json({ error: 'Unknown translation.' });
    if (!/^[1-3A-Z]{3}$/i.test(book) || !/^\d{1,3}$/.test(chapter)) {
      return res.status(400).json({ error: 'Invalid book or chapter.' });
    }
    const id = req.params.translation.toUpperCase();
    const isEsv = translation.provider === 'esv';
    const apiKey = isEsv ? process.env.ESV_API_KEY : process.env.API_BIBLE_KEY;
    if (!apiKey) return res.status(503).json({ error: `${isEsv ? 'ESV_API_KEY' : 'API_BIBLE_KEY'} is not configured on the server.` });

    const key = `${id}/${book.toUpperCase()}/${chapter}`;
    const ttl = isEsv ? ESV_CACHE_TTL : CACHE_TTL;
    const hit = cache.get(key);
    if (hit && Date.now() - hit.at < ttl) return res.json(hit.payload);

    try {
      let payload;
      if (isEsv) {
        const bookNum = BOOK_ORDER.indexOf(book.toUpperCase()) + 1;
        if (!bookNum) return res.status(400).json({ error: 'Invalid book.' });
        const prefix = String(bookNum).padStart(2, '0') + String(Number(chapter)).padStart(3, '0');
        const qs = new URLSearchParams({
          q: `${prefix}001-${prefix}999`,
          'include-passage-references': 'false', 'include-verse-numbers': 'true', 'include-first-verse-numbers': 'true',
          'include-footnotes': 'false', 'include-headings': 'false', 'include-short-copyright': 'false',
          'include-passage-horizontal-lines': 'false', 'include-heading-horizontal-lines': 'false',
        });
        const upstream = await fetch(`https://api.esv.org/v3/passage/text/?${qs}`, { headers: { Authorization: `Token ${apiKey}` } });
        if (upstream.status === 429) return res.status(429).json({ error: 'ESV rate limit reached. Try again in a minute.' });
        if (!upstream.ok) return res.status(502).json({ error: `Bible provider returned ${upstream.status}.` });
        const body = await upstream.json();
        const verses = parseChapterText(body.passages?.[0]);
        if (verses.length === 0) return res.status(404).json({ error: 'Chapter not found.' });
        payload = { translation: id, verses, copyright: '', fumsToken: null };
      } else {
        const qs = new URLSearchParams({
          'content-type': 'text', 'include-notes': 'false', 'include-titles': 'false',
          'include-chapter-numbers': 'false', 'include-verse-numbers': 'true', 'include-verse-spans': 'false',
        });
        const upstream = await fetch(
          `${API_BASE}/bibles/${translation.bibleId}/chapters/${book.toUpperCase()}.${chapter}?${qs}`,
          { headers: { 'api-key': apiKey } },
        );
        if (upstream.status === 404) return res.status(404).json({ error: 'Chapter not found.' });
        if (!upstream.ok) return res.status(502).json({ error: `Bible provider returned ${upstream.status}.` });
        const body = await upstream.json();
        const verses = parseChapterText(body.data?.content);
        if (verses.length === 0) return res.status(502).json({ error: 'Bible provider returned no verses.' });
        payload = { translation: id, verses, copyright: body.data?.copyright ?? '', fumsToken: body.meta?.fumsToken ?? null };
      }
      const max = isEsv ? ESV_CACHE_MAX : CACHE_MAX;
      if (cache.size >= CACHE_MAX + ESV_CACHE_MAX) cache.delete(cache.keys().next().value);
      if (isEsv) {
        const esvKeys = [...cache.keys()].filter((k) => k.startsWith('ESV/'));
        if (esvKeys.length >= max) cache.delete(esvKeys[0]);
      }
      cache.set(key, { at: Date.now(), payload });
      res.json(payload);
    } catch {
      res.status(502).json({ error: 'Could not reach the Bible provider.' });
    }
  });
}