#!/usr/bin/env node
/**
 * Füllt Locale-JSONs: Blätter, die nach deepMerge(de, locale) noch Deutsch sind,
 * werden übersetzt (MyMemory, Fallback Google) und als Override geschrieben.
 *
 * Cache: scripts/.i18n-translate-cache.json
 *
 * Usage:
 *   node scripts/fill-i18n-locales.js --locale en-US
 *   node scripts/fill-i18n-locales.js --all --delay 450
 */

const fs = require('fs');
const path = require('path');

const ROOT = path.resolve(__dirname, '..');
const LOCALES_DIR = path.join(ROOT, 'frontend', 'src', 'i18n', 'locales');
const CACHE_FILE = path.join(__dirname, '.i18n-translate-cache.json');
const TRANSLATE_PKG = path.join(ROOT, 'frontend', 'node_modules', '@vitalets/google-translate-api');

const PLACEHOLDER_RE = /\{[^}]+\}/g;

const LOCALE_TARGETS = {
  'en-US': 'en',
  'en-GB': 'en',
  'en-AU': 'en',
  es: 'es',
  fr: 'fr',
  it: 'it',
  pl: 'pl',
  ja: 'ja',
  zh: 'zh-CN',
  th: 'th',
  tl: 'tl',
  fil: 'tl',
  'de-CH': 'de',
};

const SKIP_LOCALES = new Set(['de', 'de-extended']);

const ALL_FILL_ORDER = [
  'en-US',
  'en-GB',
  'en-AU',
  'fr',
  'es',
  'it',
  'pl',
  'ja',
  'zh',
  'th',
  'tl',
  'fil',
  'de-CH',
];

function deepMergeMessages(base, override) {
  if (!base || typeof base !== 'object' || Array.isArray(base)) {
    return override ?? base;
  }
  const result = { ...base };
  for (const [key, value] of Object.entries(override || {})) {
    if (
      value &&
      typeof value === 'object' &&
      !Array.isArray(value) &&
      result[key] &&
      typeof result[key] === 'object' &&
      !Array.isArray(result[key])
    ) {
      result[key] = deepMergeMessages(result[key], value);
    } else {
      result[key] = value;
    }
  }
  return result;
}

function flatten(obj, prefix = '', out = {}) {
  for (const [key, value] of Object.entries(obj || {})) {
    const nextKey = prefix ? `${prefix}.${key}` : key;
    if (value && typeof value === 'object' && !Array.isArray(value)) {
      flatten(value, nextKey, out);
    } else if (typeof value === 'string') {
      out[nextKey] = value;
    }
  }
  return out;
}

function setByPath(obj, dotPath, value) {
  const parts = dotPath.split('.');
  let cur = obj;
  for (let i = 0; i < parts.length - 1; i++) {
    if (!cur[parts[i]] || typeof cur[parts[i]] !== 'object') {
      cur[parts[i]] = {};
    }
    cur = cur[parts[i]];
  }
  cur[parts[parts.length - 1]] = value;
}

function buildOverrides(deFlat, targetFlat) {
  const out = {};
  for (const [key, value] of Object.entries(targetFlat)) {
    if (value !== deFlat[key]) {
      setByPath(out, key, value);
    }
  }
  return out;
}

function protectPlaceholders(text) {
  const tokens = [];
  const safe = text.replace(PLACEHOLDER_RE, (m) => {
    const token = `__PH${tokens.length}__`;
    tokens.push(m);
    return token;
  });
  return { safe, tokens };
}

function restorePlaceholders(text, tokens) {
  let out = text;
  for (let i = 0; i < tokens.length; i++) {
    out = out.replace(new RegExp(`__\\s*PH\\s*${i}\\s*__`, 'gi'), tokens[i]);
    out = out.replace(`__PH${i}__`, tokens[i]);
  }
  return out;
}

function loadCache() {
  if (!fs.existsSync(CACHE_FILE)) return {};
  try {
    return JSON.parse(fs.readFileSync(CACHE_FILE, 'utf8'));
  } catch {
    return {};
  }
}

function saveCache(cache) {
  fs.writeFileSync(CACHE_FILE, JSON.stringify(cache, null, 2), 'utf8');
}

function sleep(ms) {
  return new Promise((r) => setTimeout(r, ms));
}

function parseArgs() {
  const args = process.argv.slice(2);
  let locale = null;
  let all = false;
  let delay = 450;
  let dryRun = false;
  let noGoogle = false;
  let enFallback = false;
  let skipEn = false;
  for (let i = 0; i < args.length; i++) {
    if (args[i] === '--locale' && args[i + 1]) locale = args[++i];
    else if (args[i] === '--all') all = true;
    else if (args[i] === '--delay' && args[i + 1]) delay = parseInt(args[++i], 10) || 450;
    else if (args[i] === '--dry-run') dryRun = true;
    else if (args[i] === '--no-google') noGoogle = true;
    else if (args[i] === '--en-fallback') enFallback = true;
    else if (args[i] === '--skip-en') skipEn = true;
  }
  return { locale, all, delay, dryRun, noGoogle, enFallback, skipEn };
}

async function mymemoryTranslate(text, from, to) {
  const url = new URL('https://api.mymemory.translated.net/get');
  url.searchParams.set('q', text.slice(0, 450));
  url.searchParams.set('langpair', `${from}|${to}`);
  const res = await fetch(url);
  const data = await res.json();
  if (data.quotaFinished) {
    throw new Error('MyMemory quota finished');
  }
  if (data.responseStatus !== 200) {
    throw new Error(data.responseDetails || `MyMemory status ${data.responseStatus}`);
  }
  return data.responseData.translatedText;
}

async function googleTranslate(translateFn, text, from, to) {
  const res = await translateFn(text, { from, to });
  return res.text;
}

async function translateText(providers, text, from, to, cache) {
  const cacheKey = `${from}|${to}|${text}`;
  if (cache[cacheKey]) return cache[cacheKey];

  const { safe, tokens } = protectPlaceholders(text);
  let out;
  let lastErr;
  for (const provider of providers) {
    try {
      const raw = await provider(safe, from, to);
      out = restorePlaceholders(raw, tokens);
      out = out.replace(/&amp;/g, '&').replace(/&lt;/g, '<').replace(/&gt;/g, '>');
      cache[cacheKey] = out;
      return out;
    } catch (e) {
      lastErr = e;
      await sleep(2000);
    }
  }
  throw lastErr;
}

function bootstrapEnFromGb(deFlat, mergedFlat) {
  const gbJson = JSON.parse(fs.readFileSync(path.join(LOCALES_DIR, 'en-GB.json'), 'utf8'));
  const de = JSON.parse(fs.readFileSync(path.join(LOCALES_DIR, 'de.json'), 'utf8'));
  const gbFlat = flatten(deepMergeMessages(de, gbJson));
  let n = 0;
  for (const k of Object.keys(deFlat)) {
    if (mergedFlat[k] === deFlat[k] && gbFlat[k] && gbFlat[k] !== deFlat[k]) {
      mergedFlat[k] = gbFlat[k];
      n++;
    }
  }
  return n;
}

function bootstrapEnFromUs(deFlat, mergedFlat, enFlat) {
  if (!enFlat) return 0;
  let n = 0;
  for (const k of Object.keys(deFlat)) {
    if (mergedFlat[k] === deFlat[k] && enFlat[k] && enFlat[k] !== deFlat[k]) {
      mergedFlat[k] = enFlat[k];
      n++;
    }
  }
  return n;
}

async function fillLocale(code, opts) {
  const { providers, cache, delay, dryRun, enFlat, enFallback } = opts;
  const targetLang = LOCALE_TARGETS[code];
  const de = JSON.parse(fs.readFileSync(path.join(LOCALES_DIR, 'de.json'), 'utf8'));
  const deFlat = flatten(de);
  const localePath = path.join(LOCALES_DIR, `${code}.json`);
  const localeJson = JSON.parse(fs.readFileSync(localePath, 'utf8'));
  const mergedFlat = flatten(deepMergeMessages(JSON.parse(JSON.stringify(de)), localeJson));

  if (code === 'en-US' || code === 'en-AU') {
    const copied = bootstrapEnFromGb(deFlat, mergedFlat);
    if (copied) console.log(`[${code}] bootstrapped ${copied} strings from en-GB`);
  }
  if ((code === 'en-GB' || code === 'en-AU') && enFlat) {
    const copied = bootstrapEnFromUs(deFlat, mergedFlat, enFlat);
    if (copied) console.log(`[${code}] bootstrapped ${copied} strings from en-US`);
  }

  const keysToFix = Object.keys(deFlat).filter((k) => mergedFlat[k] === deFlat[k]);
  if (!keysToFix.length) {
    console.log(`[${code}] nothing to fill`);
    if (!dryRun) {
      fs.writeFileSync(localePath, `${JSON.stringify(buildOverrides(deFlat, mergedFlat), null, 2)}\n`, 'utf8');
    }
    return;
  }

  const uniqueTexts = new Map();
  for (const k of keysToFix) {
    const from = enFlat && enFlat[k] && enFlat[k] !== deFlat[k] ? 'en' : 'de';
    const text = from === 'en' ? enFlat[k] : deFlat[k];
    const mapKey = `${from}\0${text}`;
    if (!uniqueTexts.has(mapKey)) uniqueTexts.set(mapKey, { from, text, keys: [] });
    uniqueTexts.get(mapKey).keys.push(k);
  }

  console.log(`[${code}] ${keysToFix.length} keys, ${uniqueTexts.size} unique, target=${targetLang}`);

  if (code === 'de-CH') {
    for (const k of keysToFix) {
      const base = deFlat[k];
      mergedFlat[k] = base.replace(/ß/g, 'ss');
    }
  } else {
    let done = 0;
    const failed = [];
    for (const entry of uniqueTexts.values()) {
      const { from, text, keys } = entry;
      const cacheKey = `${from}|${targetLang}|${text}`;
      let translated;
      if (from === 'en' && targetLang === 'en') {
        translated = text;
      } else if (cache[cacheKey]) {
        translated = cache[cacheKey];
      } else if (dryRun) {
        translated = `[${targetLang}] ${text.slice(0, 30)}`;
      } else {
        try {
          translated = await translateText(providers, text, from, targetLang, cache);
          await sleep(delay);
        } catch (e) {
          console.error(`[${code}] skip: ${text.slice(0, 50)}… (${e.message})`);
          failed.push(entry);
          continue;
        }
      }
      for (const k of keys) mergedFlat[k] = translated;
      done++;
      if (done % 50 === 0) {
        console.log(`[${code}] ${done}/${uniqueTexts.size} (failed ${failed.length})`);
        saveCache(cache);
      }
    }
    saveCache(cache);

    if (failed.length && !dryRun) {
      console.log(`[${code}] retrying ${failed.length} failed strings…`);
      await sleep(5000);
      for (const { from, text, keys } of failed) {
        const cacheKey = `${from}|${targetLang}|${text}`;
        try {
          const translated = cache[cacheKey] || (await translateText(providers, text, from, targetLang, cache));
          for (const k of keys) mergedFlat[k] = translated;
          await sleep(delay);
        } catch (e) {
          if (enFallback && from === 'en') {
            for (const k of keys) mergedFlat[k] = text;
          } else {
            console.error(`[${code}] final skip: ${text.slice(0, 40)}…`);
          }
        }
      }
      saveCache(cache);
    }
  }

  const overrides = buildOverrides(deFlat, mergedFlat);
  if (!dryRun) {
    fs.writeFileSync(localePath, `${JSON.stringify(overrides, null, 2)}\n`, 'utf8');
  }
  const stillDe = Object.keys(deFlat).filter((k) => mergedFlat[k] === deFlat[k]).length;
  console.log(`[${code}] overrides=${Object.keys(flatten(overrides)).length}, stillDe=${stillDe}`);
}

async function main() {
  const { locale, all, delay, dryRun, noGoogle, enFallback, skipEn } = parseArgs();
  const providers = [
    (text, from, to) => mymemoryTranslate(text, from, to),
  ];
  if (!noGoogle && fs.existsSync(TRANSLATE_PKG)) {
    const { translate: translateFn } = require(TRANSLATE_PKG);
    providers.push((text, from, to) => googleTranslate(translateFn, text, from, to));
  }

  const cache = loadCache();
  let codes = all ? ALL_FILL_ORDER : locale ? [locale] : null;
  if (skipEn && codes) {
    codes = codes.filter((c) => !['en-US', 'en-GB', 'en-AU'].includes(c));
  }
  if (!codes) {
    console.error('Usage: --locale <code> | --all [--delay ms]');
    process.exit(1);
  }

  let enFlat = null;
  const de = JSON.parse(fs.readFileSync(path.join(LOCALES_DIR, 'de.json'), 'utf8'));
  const enUsPath = path.join(LOCALES_DIR, 'en-US.json');
  if (fs.existsSync(enUsPath)) {
    enFlat = flatten(deepMergeMessages(de, JSON.parse(fs.readFileSync(enUsPath, 'utf8'))));
  }

  for (const code of codes) {
    if (SKIP_LOCALES.has(code)) continue;
    if (!(code in LOCALE_TARGETS)) continue;
    await fillLocale(code, { providers, cache, delay, dryRun, enFlat, enFallback });
    if (all && !dryRun) await sleep(8000);
    if (code === 'en-US' && !dryRun) {
      enFlat = flatten(deepMergeMessages(de, JSON.parse(fs.readFileSync(enUsPath, 'utf8'))));
    }
  }
  saveCache(cache);
  console.log('Done.');
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});