/**
 * Erzeugt fr/falukant.json neu aus de/falukant.json (google-translate-api-x).
 * Stellt sicher, dass benannte Platzhalter {name} exakt wie im Deutschen bleiben.
 *
 * Aus frontend/: node scripts/smooth-fr-falukant.mjs
 */
import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';
import { translate } from 'google-translate-api-x';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const DE_PATH = path.join(__dirname, '../src/i18n/locales/de/falukant.json');
const FR_PATH = path.join(__dirname, '../src/i18n/locales/fr/falukant.json');
const CACHE_PATH = path.join(__dirname, '.falukant-fr-smooth-cache.json');
const CONCURRENCY = Math.max(1, parseInt(process.env.I18N_MT_CONCURRENCY || '3', 10));
const DELAY_MS = Math.max(0, parseInt(process.env.I18N_MT_DELAY_MS || '400', 10));

function loadCache() {
  try {
    return JSON.parse(fs.readFileSync(CACHE_PATH, 'utf8'));
  } catch {
    return {};
  }
}

function saveCache(cache) {
  fs.writeFileSync(CACHE_PATH, JSON.stringify(cache, null, 0), 'utf8');
}

function shouldSkipTranslation(str) {
  if (typeof str !== 'string' || str.length === 0) return true;
  if (/^[\d\s./:\\\-–—:]+$/u.test(str) && str.length < 96) return true;
  if (/^([dDMYHhms\.\/:,\[\]'\s-]|yyyy|yy)+$/i.test(str.trim()) && str.length < 96) return true;
  return false;
}

/** Ersetzt {…}-Tokens in der Übersetzung durch die Namen aus dem Deutschen (gleiche Reihenfolge). */
function alignPlaceholders(deStr, frStr) {
  const deNames = [...deStr.matchAll(/\{([a-zA-Z_][a-zA-Z0-9_]*)\}/g)].map((m) => m[1]);
  if (deNames.length === 0) return frStr;
  let i = 0;
  return frStr.replace(/\{[^}]+\}/g, () => {
    const name = deNames[i];
    i += 1;
    return name !== undefined ? `{${name}}` : '{}';
  });
}

async function translateOne(text, cache) {
  if (shouldSkipTranslation(text)) return text;
  if (cache[text]) return cache[text];
  for (let attempt = 0; attempt < 4; attempt++) {
    try {
      const res = await translate(text, { from: 'de', to: 'fr' });
      const aligned = alignPlaceholders(text, res.text);
      cache[text] = aligned;
      return aligned;
    } catch {
      await new Promise((r) => setTimeout(r, 800 * (attempt + 1)));
    }
  }
  console.warn('Übersetzung fehlgeschlagen:', text.slice(0, 72));
  cache[text] = text;
  return text;
}

function collectStrings(node, set) {
  if (typeof node === 'string') {
    set.add(node);
    return;
  }
  if (Array.isArray(node)) {
    for (const x of node) collectStrings(x, set);
    return;
  }
  if (node && typeof node === 'object') {
    for (const k of Object.keys(node)) collectStrings(node[k], set);
  }
}

function applyMap(node, cache) {
  if (typeof node === 'string') {
    if (shouldSkipTranslation(node)) return node;
    return cache[node] !== undefined ? cache[node] : node;
  }
  if (Array.isArray(node)) return node.map((x) => applyMap(x, cache));
  if (node && typeof node === 'object') {
    const out = {};
    for (const k of Object.keys(node)) {
      out[k] = applyMap(node[k], cache);
    }
    return out;
  }
  return node;
}

async function main() {
  const deRoot = JSON.parse(fs.readFileSync(DE_PATH, 'utf8'));
  const cache = loadCache();
  const all = new Set();
  collectStrings(deRoot, all);
  const unique = [...all].filter((s) => !shouldSkipTranslation(s));
  const missing = unique.filter((s) => cache[s] === undefined);
  console.log(`Falukant: ${unique.length} übersetzbare Strings, ${missing.length} ohne Cache.`);

  let next = 0;
  let done = 0;

  async function worker() {
    for (;;) {
      const i = next++;
      if (i >= missing.length) return;
      const s = missing[i];
      await translateOne(s, cache);
      done++;
      if (done % 40 === 0) {
        saveCache(cache);
        console.log(`… ${done}/${missing.length}`);
      }
      if (DELAY_MS > 0) await new Promise((r) => setTimeout(r, DELAY_MS));
    }
  }

  const workers = Array.from({ length: Math.min(CONCURRENCY, Math.max(1, missing.length)) }, () => worker());
  await Promise.all(workers);
  saveCache(cache);

  const out = applyMap(deRoot, cache);
  fs.writeFileSync(FR_PATH, `${JSON.stringify(out, null, 4)}\n`, 'utf8');
  console.log('Geschrieben:', FR_PATH);
}

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