import mysql from 'mysql2/promise';

export function isDatabaseConfigured() {
  return Boolean(
    process.env.DATABASE_URL ||
      (process.env.MYSQL_HOST && process.env.MYSQL_DATABASE),
  );
}

export function createDbPool() {
  if (!isDatabaseConfigured()) {
    throw new Error('MySQL 未配置，请在 .env 设置 DATABASE_URL 或 MYSQL_*');
  }

  if (process.env.DATABASE_URL) {
    return mysql.createPool(process.env.DATABASE_URL);
  }

  return mysql.createPool({
    host: process.env.MYSQL_HOST ?? 'localhost',
    port: Number(process.env.MYSQL_PORT ?? 3306),
    user: process.env.MYSQL_USER ?? 'boot',
    password: process.env.MYSQL_PASSWORD ?? '',
    database: process.env.MYSQL_DATABASE ?? 'tkmind',
    waitForConnections: true,
    connectionLimit: 10,
  });
}