import { join } from 'node:path';
import { DataSource } from 'typeorm';
import { PHASE_A_ENTITIES } from './entities';

function requiredEnvironmentVariable(key: string): string {
  const value = process.env[key];
  if (!value) throw new Error(`Missing required environment variable: ${key}`);
  return value;
}

function databasePort(): number {
  const port = Number(process.env.DB_PORT ?? 5432);
  if (!Number.isInteger(port) || port < 1 || port > 65535) {
    throw new Error('DB_PORT must be a valid TCP port');
  }
  return port;
}

export const migrationDataSource = new DataSource({
  type: 'postgres',
  host: requiredEnvironmentVariable('DB_HOST'),
  port: databasePort(),
  database: requiredEnvironmentVariable('DB_NAME'),
  username: requiredEnvironmentVariable('DB_MIGRATION_USER'),
  password: requiredEnvironmentVariable('DB_MIGRATION_PASSWORD'),
  entities: PHASE_A_ENTITIES,
  migrations: [join(__dirname, 'migrations', '*.{js,ts}')],
  migrationsTableName: 'typeorm_migrations',
  synchronize: false,
  migrationsRun: false,
  logging: false,
  applicationName: 'dhv2-migrations',
  connectTimeoutMS: 5000,
});