const db = require('./database');
const storage = require('./storage');
const sharp = require('sharp');

// Limit of concurrency
const CONCURRENCY = 15;

async function runBackfill() {
  console.log('🚀 Iniciando backfill de thumbnails concorrido...');
  
  // 1. Inicializar banco de dados
  await db.initDatabase();
  console.log('✅ Banco de dados inicializado.');
  
  // 2. Carregar configurações do Wasabi a partir do banco
  await storage.loadConfigFromDb();
  console.log('✅ Configuração do Wasabi carregada.');
  
  // 3. Buscar todas as imagens que não possuem thumb_filename
  const query = "SELECT id, filename, client_name, patient_name FROM images WHERE (thumb_filename IS NULL OR thumb_filename = '') AND enabled = 1";
  const images = await db.all(query);
  console.log(`🔎 Encontradas ${images.length} imagens pendentes de thumbnail.`);
  
  let successCount = 0;
  let failCount = 0;
  
  // Worker function to process a single image
  async function processImage(img) {
    try {
      // a. Baixar imagem original do Wasabi
      const buffer = await storage.getImageBuffer(img.filename, img.client_name, img.patient_name, false);
      if (!buffer) {
        throw new Error(`Não foi possível obter o buffer para ${img.filename}`);
      }
      
      // b. Gerar thumbnail WebP
      const thumbBuffer = await sharp(buffer)
        .resize({ width: 400, height: 400, fit: 'inside', withoutEnlargement: true })
        .webp({ quality: 80, effort: 4 })
        .toBuffer();
      
      // c. Salvar thumbnail no Wasabi
      const thumbFilename = `thumb_${Date.now()}_${img.id}.webp`;
      await storage.saveImage(thumbFilename, thumbBuffer, img.client_name, img.patient_name, false);
      
      // d. Atualizar no banco de dados
      await db.run('UPDATE images SET thumb_filename = ? WHERE id = ?', [thumbFilename, img.id]);
      
      console.log(`✅ [ID ${img.id}] Thumbnail salvo com sucesso: ${thumbFilename} (Paciente: ${img.patient_name})`);
      successCount++;
    } catch (err) {
      console.error(`❌ [ID ${img.id}] Erro no processamento da imagem:`, err.message);
      failCount++;
    }
  }

  // Concurrency queue
  const queue = [...images];
  const workers = [];

  async function worker() {
    while (queue.length > 0) {
      const img = queue.shift();
      if (!img) break;
      await processImage(img);
    }
  }

  // Start workers
  for (let i = 0; i < Math.min(CONCURRENCY, images.length); i++) {
    workers.push(worker());
  }

  // Wait for all to complete
  await Promise.all(workers);
  
  console.log('\n=========================================');
  console.log('📊 Resumo do Backfill Concorrido:');
  console.log(`- Sucesso: ${successCount}`);
  console.log(`- Falhas : ${failCount}`);
  console.log('=========================================');
  
  process.exit(0);
}

runBackfill().catch(err => {
  console.error('❌ Erro fatal no script de backfill:', err);
  process.exit(1);
});