const { Sequelize } = require('sequelize');
const path = require('path');
const fs = require('fs');

// Load environment variables
require('dotenv').config();

const runMigrations = async () => {
  console.log('🔄 Starting database migrations...\n');

  try {
    // Create Sequelize instance
    const sequelize = new Sequelize(
      process.env.DB_NAME,
      process.env.DB_USER,
      process.env.DB_PASSWORD,
      {
        host: process.env.DB_HOST,
        port: process.env.DB_PORT,
        dialect: 'postgres',
        logging: console.log,
      }
    );

    // Test database connection
    console.log('📡 Testing database connection...');
    await sequelize.authenticate();
    console.log('✅ Database connection established successfully.\n');

    // Get migrations directory
    const migrationsDir = path.join(__dirname, '../migrations');
    
    if (!fs.existsSync(migrationsDir)) {
      console.log('📁 No migrations directory found. Creating...');
      fs.mkdirSync(migrationsDir, { recursive: true });
    }

    // Get all migration files
    const migrationFiles = fs.readdirSync(migrationsDir)
      .filter(file => file.endsWith('.js'))
      .sort(); // Sort to ensure proper order

    if (migrationFiles.length === 0) {
      console.log('📝 No migration files found.');
      return;
    }

    console.log(`📋 Found ${migrationFiles.length} migration files:`);
    migrationFiles.forEach(file => console.log(`   - ${file}`));
    console.log('');

    // Create migrations table if it doesn't exist
    await sequelize.getQueryInterface().createTable('SequelizeMeta', {
      name: {
        type: Sequelize.STRING,
        primaryKey: true,
        allowNull: false
      }
    }).catch(() => {
      // Table already exists, ignore error
    });

    // Get already executed migrations
    const [executedMigrations] = await sequelize.query(
      'SELECT name FROM "SequelizeMeta" ORDER BY name'
    );
    const executedNames = executedMigrations.map(row => row.name);

    // Run pending migrations
    for (const file of migrationFiles) {
      const migrationName = file.replace('.js', '');
      
      if (executedNames.includes(migrationName)) {
        console.log(`⏭️  Skipping already executed migration: ${file}`);
        continue;
      }

      console.log(`🚀 Running migration: ${file}`);
      
      try {
        // Load and execute migration
        const migration = require(path.join(migrationsDir, file));
        await migration.up(sequelize.getQueryInterface(), Sequelize);
        
        // Record successful migration
        await sequelize.query(
          'INSERT INTO "SequelizeMeta" (name) VALUES (?)',
          {
            replacements: [migrationName],
            type: Sequelize.QueryTypes.INSERT
          }
        );
        
        console.log(`✅ Migration completed: ${file}\n`);
        
      } catch (error) {
        console.error(`❌ Migration failed: ${file}`);
        console.error('Error:', error.message);
        process.exit(1);
      }
    }

    console.log('🎉 All migrations completed successfully!');
    await sequelize.close();

  } catch (error) {
    console.error('❌ Migration process failed:', error);
    process.exit(1);
  }
};

// Run migrations if called directly
if (require.main === module) {
  runMigrations();
}

module.exports = runMigrations;