const mysql = require('mysql2/promise');

let pool;

function initPool() {
  if (pool) {
    pool.end().catch(e => console.error('Error closing pool:', e));
  }
  pool = mysql.createPool({
    host: process.env.MYSQL_HOST || 'localhost',
    port: parseInt(process.env.MYSQL_PORT) || 3306,
    user: process.env.MYSQL_USER || 'root',
    password: process.env.MYSQL_PASSWORD || '',
    database: process.env.MYSQL_DATABASE || 'display_wall',
    waitForConnections: true,
    connectionLimit: 10,
    queueLimit: 0
  });
}

async function checkHealth() {
  try {
    if (!pool) return { status: 'down', error: 'Database pool not initialized' };
    await pool.query('SELECT 1');
    return { status: 'up' };
  } catch (err) {
    return { status: 'down', error: err.message };
  }
}

initPool();

module.exports = {
  query: (...args) => pool.query(...args),
  initPool,
  checkHealth
};