import { PrismaClient as CentralPrismaClient } from '.prisma/central';
import knex, { Knex } from 'knex';
import { createDecipheriv } from 'crypto';

// Encryption configuration - must match the one used in tenant service
const ALGORITHM = 'aes-256-cbc';

/**
 * Decrypt a tenant's database password
 */
function decryptPassword(encryptedPassword: string): string {
  try {
    // Check if password is already plaintext (for legacy/development)
    if (!encryptedPassword.includes(':')) {
      console.warn('⚠️  Password appears to be unencrypted, using as-is');
      return encryptedPassword;
    }

    const key = Buffer.from(process.env.ENCRYPTION_KEY, 'hex');
    const parts = encryptedPassword.split(':');
    if (parts.length !== 2) {
      throw new Error('Invalid encrypted password format');
    }

    const iv = Buffer.from(parts[0], 'hex');
    const encrypted = parts[1];
    
    const decipher = createDecipheriv(ALGORITHM, key, iv);
    
    let decrypted = decipher.update(encrypted, 'hex', 'utf8');
    decrypted += decipher.final('utf8');
    
    return decrypted;
  } catch (error) {
    console.error('Error decrypting password:', error);
    throw error;
  }
}

/**
 * Create a Knex connection for a specific tenant
 */
function createTenantKnexConnection(tenant: any): Knex {
  const decryptedPassword = decryptPassword(tenant.dbPassword);

  return knex({
    client: 'mysql2',
    connection: {
      host: tenant.dbHost,
      port: tenant.dbPort,
      user: tenant.dbUsername,
      password: decryptedPassword,
      database: tenant.dbName,
    },
    migrations: {
      tableName: 'knex_migrations',
      directory: './migrations/tenant',
    },
  });
}

/**
 * Run migrations for a specific tenant
 */
async function migrateTenant(tenant: any): Promise<void> {
  console.log(`\n🔄 Migrating tenant: ${tenant.name} (${tenant.dbName})`);
  
  const tenantKnex = createTenantKnexConnection(tenant);
  
  try {
    const [batchNo, log] = await tenantKnex.migrate.latest();
    
    if (log.length === 0) {
      console.log(`✅ ${tenant.name}: Already up to date`);
    } else {
      console.log(`✅ ${tenant.name}: Ran ${log.length} migrations:`);
      log.forEach((migration) => {
        console.log(`   - ${migration}`);
      });
    }
  } catch (error) {
    console.error(`❌ ${tenant.name}: Migration failed:`, error.message);
    throw error;
  } finally {
    await tenantKnex.destroy();
  }
}

/**
 * Main function to migrate all active tenants
 */
async function migrateAllTenants() {
  console.log('🚀 Starting migration for all tenants...\n');
  
  const centralPrisma = new CentralPrismaClient();
  
  try {
    // Fetch all active tenants
    const tenants = await centralPrisma.tenant.findMany({
      where: {
        status: 'ACTIVE',
      },
      orderBy: {
        name: 'asc',
      },
    });

    if (tenants.length === 0) {
      console.log('⚠️  No active tenants found.');
      return;
    }

    console.log(`📋 Found ${tenants.length} active tenant(s)\n`);

    let successCount = 0;
    let failureCount = 0;
    const failures: { tenant: string; error: string }[] = [];

    // Migrate each tenant sequentially
    for (const tenant of tenants) {
      try {
        await migrateTenant(tenant);
        successCount++;
      } catch (error) {
        failureCount++;
        failures.push({
          tenant: tenant.name,
          error: error.message,
        });
      }
    }

    // Print summary
    console.log('\n' + '='.repeat(60));
    console.log('📊 Migration Summary');
    console.log('='.repeat(60));
    console.log(`✅ Successful: ${successCount}`);
    console.log(`❌ Failed: ${failureCount}`);

    if (failures.length > 0) {
      console.log('\n❌ Failed Tenants:');
      failures.forEach(({ tenant, error }) => {
        console.log(`   - ${tenant}: ${error}`);
      });
      process.exit(1);
    } else {
      console.log('\n🎉 All tenant migrations completed successfully!');
    }
  } catch (error) {
    console.error('❌ Fatal error:', error);
    process.exit(1);
  } finally {
    await centralPrisma.$disconnect();
  }
}

// Run the migration
migrateAllTenants()
  .then(() => {
    process.exit(0);
  })
  .catch((error) => {
    console.error('Unhandled error:', error);
    process.exit(1);
  });