<?php
// db/config.php

// --- Database Credentials ---
// In a real environment, use environment variables.
define('DB_HOST', '127.0.0.1');
define('DB_NAME', 'asset_management');
define('DB_USER', 'asset_admin');
define('DB_PASS', 'password');
define('DB_CHARSET', 'utf8mb4');

/**
 * Establishes a PDO database connection.
 *
 * @return PDO The PDO database connection object.
 * @throws PDOException if the connection fails.
 */
function getDbConnection() {
    static $pdo = null;

    if ($pdo === null) {
        $dsn = "mysql:host=" . DB_HOST . ";dbname=" . DB_NAME . ";charset=" . DB_CHARSET;
        $options = [
            PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::ATTR_EMULATE_PREPARES   => false,
        ];
        try {
            $pdo = new PDO($dsn, DB_USER, DB_PASS, $options);
        } catch (\PDOException $e) {
            // For development, it's okay to see the error.
            // In production, log this and show a generic error message.
            throw new \PDOException($e->getMessage(), (int)$e->getCode());
        }
    }
    return $pdo;
}
?>