#!/usr/bin/env node
/**
 * Batch translate EN locale JSON files to Te Reo Māori (MI) using DeepL API.
 * Preserves JSON structure, translates all leaf string values.
 *
 * Usage: node scripts/translate-to-mi.js [filename.json] [--all]
 *
 * Uses DeepL Pro API with quality_optimized model (required for MI).
 * Batches requests to stay within API limits.
 */

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

const DEEPL_API_KEY = process.env.DEEPL_API_KEY || 'c23731a2-33e8-4996-81f1-324dbb677df6';
const DEEPL_API_URL = 'https://api.deepl.com/v2/translate';
const EN_DIR = path.join(__dirname, '..', 'public', 'locales', 'en');
const MI_DIR = path.join(__dirname, '..', 'public', 'locales', 'mi');
const BATCH_SIZE = 50; // DeepL allows up to 50 texts per request
const DELAY_MS = 200; // Rate limiting between batches

// Files to skip (already complete or special)
const SKIP_FILES = ['faq.json.backup-1761644843'];

/**
 * Extract all leaf string values from nested JSON, preserving paths
 */
function extractLeafStrings(obj, prefix = '') {
  const results = [];
  if (typeof obj === 'string') {
    results.push({ path: prefix, value: obj });
  } else if (Array.isArray(obj)) {
    obj.forEach((item, i) => {
      results.push(...extractLeafStrings(item, `${prefix}[${i}]`));
    });
  } else if (obj && typeof obj === 'object') {
    for (const [key, val] of Object.entries(obj)) {
      const newPath = prefix ? `${prefix}.${key}` : key;
      results.push(...extractLeafStrings(val, newPath));
    }
  }
  return results;
}

/**
 * Set a value at a dot/bracket path in a nested object
 */
function setNestedValue(obj, pathStr, value) {
  const parts = pathStr.split(/\.(?![^\[]*\])/).flatMap(part => {
    const matches = [];
    let remaining = part;
    while (remaining) {
      const bracketMatch = remaining.match(/^([^\[]*)\[(\d+)\](.*)/);
      if (bracketMatch) {
        if (bracketMatch[1]) matches.push(bracketMatch[1]);
        matches.push(parseInt(bracketMatch[2]));
        remaining = bracketMatch[3];
        if (remaining.startsWith('.')) remaining = remaining.slice(1);
      } else {
        matches.push(remaining);
        remaining = '';
      }
    }
    return matches;
  });

  let current = obj;
  for (let i = 0; i < parts.length - 1; i++) {
    const part = parts[i];
    const nextPart = parts[i + 1];
    if (current[part] === undefined) {
      current[part] = typeof nextPart === 'number' ? [] : {};
    }
    current = current[part];
  }
  current[parts[parts.length - 1]] = value;
}

/**
 * Translate a batch of texts using DeepL API
 */
function translateBatch(texts) {
  return new Promise((resolve, reject) => {
    const params = new URLSearchParams();
    texts.forEach(t => params.append('text', t));
    params.append('source_lang', 'EN');
    params.append('target_lang', 'MI');

    const postData = params.toString();
    const url = new URL(DEEPL_API_URL);

    const options = {
      hostname: url.hostname,
      port: 443,
      path: url.pathname,
      method: 'POST',
      headers: {
        'Authorization': `DeepL-Auth-Key ${DEEPL_API_KEY}`,
        'Content-Type': 'application/x-www-form-urlencoded',
        'Content-Length': Buffer.byteLength(postData)
      }
    };

    const req = https.request(options, (res) => {
      let data = '';
      res.on('data', chunk => data += chunk);
      res.on('end', () => {
        if (res.statusCode !== 200) {
          reject(new Error(`DeepL API error ${res.statusCode}: ${data}`));
          return;
        }
        try {
          const result = JSON.parse(data);
          resolve(result.translations.map(t => t.text));
        } catch (e) {
          reject(new Error(`Parse error: ${e.message}`));
        }
      });
    });

    req.on('error', reject);
    req.write(postData);
    req.end();
  });
}

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

/**
 * Translate an entire JSON file from EN to MI
 */
async function translateFile(filename) {
  const enPath = path.join(EN_DIR, filename);
  const miPath = path.join(MI_DIR, filename);

  if (!fs.existsSync(enPath)) {
    console.error(`  ✗ EN file not found: ${filename}`);
    return false;
  }

  // Load existing MI file if it exists (to preserve existing translations)
  let existingMi = {};
  if (fs.existsSync(miPath)) {
    try {
      existingMi = JSON.parse(fs.readFileSync(miPath, 'utf8'));
    } catch (e) {
      console.warn(`  ⚠ Could not parse existing MI file, will overwrite`);
    }
  }

  const enData = JSON.parse(fs.readFileSync(enPath, 'utf8'));
  const leaves = extractLeafStrings(enData);
  const existingLeaves = extractLeafStrings(existingMi);
  const existingMap = new Map(existingLeaves.map(l => [l.path, l.value]));

  // Identify which leaves need translation (not already in MI)
  const needsTranslation = leaves.filter(l => !existingMap.has(l.path));
  const alreadyTranslated = leaves.filter(l => existingMap.has(l.path));

  console.log(`  ${leaves.length} total keys, ${alreadyTranslated.length} already translated, ${needsTranslation.length} to translate`);

  if (needsTranslation.length === 0) {
    console.log(`  ✓ Already fully translated`);
    return true;
  }

  // Build output object starting with EN structure, overlaying existing MI translations
  const output = JSON.parse(JSON.stringify(enData)); // Deep clone EN structure

  // Apply existing MI translations
  for (const leaf of alreadyTranslated) {
    setNestedValue(output, leaf.path, existingMap.get(leaf.path));
  }

  // Translate in batches
  const textsToTranslate = needsTranslation.map(l => l.value);
  const translatedTexts = [];

  for (let i = 0; i < textsToTranslate.length; i += BATCH_SIZE) {
    const batch = textsToTranslate.slice(i, i + BATCH_SIZE);
    const batchNum = Math.floor(i / BATCH_SIZE) + 1;
    const totalBatches = Math.ceil(textsToTranslate.length / BATCH_SIZE);
    process.stdout.write(`  Translating batch ${batchNum}/${totalBatches} (${batch.length} texts)...`);

    try {
      const results = await translateBatch(batch);
      translatedTexts.push(...results);
      console.log(' ✓');
    } catch (e) {
      console.log(` ✗ ${e.message}`);
      return false;
    }

    if (i + BATCH_SIZE < textsToTranslate.length) {
      await sleep(DELAY_MS);
    }
  }

  // Apply translations to output
  for (let i = 0; i < needsTranslation.length; i++) {
    setNestedValue(output, needsTranslation[i].path, translatedTexts[i]);
  }

  // Write output
  fs.writeFileSync(miPath, JSON.stringify(output, null, 2) + '\n', 'utf8');
  console.log(`  ✓ Written: ${miPath}`);
  return true;
}

async function main() {
  const args = process.argv.slice(2);

  // Ensure MI directory exists
  if (!fs.existsSync(MI_DIR)) {
    fs.mkdirSync(MI_DIR, { recursive: true });
  }

  let files;
  if (args.includes('--all')) {
    files = fs.readdirSync(EN_DIR)
      .filter(f => f.endsWith('.json') && !SKIP_FILES.includes(f))
      .sort();
  } else if (args.length > 0 && !args[0].startsWith('--')) {
    files = args.filter(f => !f.startsWith('--'));
  } else {
    console.log('Usage: node scripts/translate-to-mi.js [filename.json ...] [--all]');
    console.log('  --all    Translate all EN files');
    process.exit(1);
  }

  console.log(`\n═══════════════════════════════════════════════════════════`);
  console.log(`  DEEPL TRANSLATION: EN → MI (Te Reo Māori)`);
  console.log(`═══════════════════════════════════════════════════════════\n`);
  console.log(`Files to translate: ${files.length}\n`);

  let success = 0;
  let failed = 0;

  for (const file of files) {
    console.log(`\n📄 ${file}`);
    const result = await translateFile(file);
    if (result) success++;
    else failed++;
  }

  console.log(`\n═══════════════════════════════════════════════════════════`);
  console.log(`  TRANSLATION COMPLETE`);
  console.log(`═══════════════════════════════════════════════════════════`);
  console.log(`  ✓ Success: ${success}`);
  if (failed > 0) console.log(`  ✗ Failed: ${failed}`);
  console.log(`  Total: ${files.length}\n`);
}

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