/**
 * Migration: Add encrypted storage for private keys
 *
 * Fixes: DeviceCertificate.privateKeyPem stored in plaintext - security risk
 * Changes:
 * - Add encrypted_private_key column for AES-256-GCM encrypted storage
 * - Add encryption_key_id for key management
 * - Add encryption_algorithm field
 * - Mark private_key_pem as deprecated (not removed for backwards compatibility)
 *
 * Note: Actual encryption/decryption should be handled at application level.
 * This migration only sets up the schema for encrypted storage.
 *
 * @type {import('node-pg-migrate').ColumnDefinitions | undefined}
 */
export const shorthands = undefined;

/**
 * @param pgm {import('node-pg-migrate').MigrationBuilder}
 * @param run {() => void | undefined}
 * @returns {Promise<void> | void}
 */
export const up = (pgm) => {
  console.log('Adding encrypted private key storage...');

  // Add encryption-related columns
  pgm.addColumns('device_certificates', {
    encrypted_private_key: {
      type: 'text',
      notNull: false,
      comment: 'AES-256-GCM encrypted private key (base64 encoded ciphertext + IV + auth tag)',
    },
    encryption_key_id: {
      type: 'varchar(100)',
      notNull: false,
      comment: 'Identifier for the encryption key used (for key rotation support)',
    },
    encryption_algorithm: {
      type: 'varchar(50)',
      notNull: false,
      default: 'AES-256-GCM',
      comment: 'Encryption algorithm used',
    },
    encrypted_at: {
      type: 'timestamptz',
      notNull: false,
      comment: 'Timestamp when the private key was encrypted',
    },
  });

  // Add deprecation comment to old column
  pgm.sql(`
    COMMENT ON COLUMN device_certificates.private_key_pem IS
    'DEPRECATED: Plaintext private key. Will be removed in future version.
     Use encrypted_private_key instead for secure storage.
     This column is kept for backwards compatibility during migration.';
  `);

  // Add index on encryption_key_id for key rotation queries
  pgm.createIndex('device_certificates', 'encryption_key_id', {
    name: 'idx_device_certificates_encryption_key_id',
    where: 'encryption_key_id IS NOT NULL',
  });

  // Add CHECK constraint for encryption algorithm
  pgm.addConstraint('device_certificates', 'chk_device_certificates_encryption_algorithm', {
    check: "encryption_algorithm IS NULL OR encryption_algorithm IN ('AES-256-GCM', 'AES-256-CBC', 'ChaCha20-Poly1305')",
  });

  // Create a view that excludes private key data for safer queries
  pgm.sql(`
    CREATE OR REPLACE VIEW device_certificates_public AS
    SELECT
      id,
      device_id,
      serial_number,
      fingerprint,
      certificate_type,
      status,
      subject_dn,
      issuer_dn,
      certificate_pem,
      public_key_pem,
      key_algorithm,
      key_size,
      signature_algorithm,
      issued_at,
      expires_at,
      revoked_at,
      revocation_reason,
      x509_extensions,
      usage_count,
      last_used_at,
      renewal_notified_at,
      created_at,
      updated_at,
      deleted_at,
      -- Indicate if encrypted key exists without exposing it
      CASE WHEN encrypted_private_key IS NOT NULL THEN true ELSE false END AS has_encrypted_key,
      encryption_key_id,
      encryption_algorithm,
      encrypted_at
    FROM device_certificates;

    COMMENT ON VIEW device_certificates_public IS
    'Safe view of device_certificates excluding private key data';
  `);

  console.log('Encrypted private key storage added.');
  console.log('');
  console.log('IMPORTANT: To complete the migration:');
  console.log('1. Update application code to use encrypted_private_key');
  console.log('2. Configure encryption key in environment');
  console.log('3. Run data migration to encrypt existing private keys');
  console.log('4. Once verified, clear private_key_pem column');
};

/**
 * @param pgm {import('node-pg-migrate').MigrationBuilder}
 * @param run {() => void | undefined}
 * @returns {Promise<void> | void}
 */
export const down = (pgm) => {
  console.log('Rolling back encrypted private key storage...');

  // Drop view
  pgm.sql('DROP VIEW IF EXISTS device_certificates_public;');

  // Drop constraint
  pgm.dropConstraint('device_certificates', 'chk_device_certificates_encryption_algorithm', {
    ifExists: true,
  });

  // Drop index
  pgm.dropIndex('device_certificates', 'encryption_key_id', {
    name: 'idx_device_certificates_encryption_key_id',
    ifExists: true,
  });

  // Drop columns
  pgm.dropColumns('device_certificates', [
    'encrypted_private_key',
    'encryption_key_id',
    'encryption_algorithm',
    'encrypted_at',
  ]);

  // Restore original comment
  pgm.sql(`
    COMMENT ON COLUMN device_certificates.private_key_pem IS
    'Private key in PEM format (optional, for key recovery)';
  `);

  console.log('Encrypted private key storage rollback complete.');
};