<?php
// Database utility functions
if (!defined("_VALID_ACCESS")) { exit("Direct access not allowed"); }

function get_db_connection() {
    global $db;
    if ($db === null) {
        try {
            $dsn = "mysql:host=" . DB_HOST . ";dbname=" . DB_NAME . ";charset=utf8mb4";
            $db = new PDO($dsn, DB_USER, DB_PASS, [
                PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
                PDO::ATTR_EMULATE_PREPARES => false
            ]);
        } catch (PDOException $e) {
            error_log("Database connection failed: " . $e->getMessage());
            throw new Exception("Database connection failed");
        }
    }
    return $db;
}

function db_query($sql, $params = []) {
    $db = get_db_connection();
    $stmt = $db->prepare($sql);
    $stmt->execute($params);
    return $stmt;
}

function db_fetch($sql, $params = []) {
    return db_query($sql, $params)->fetch();
}

function db_fetch_all($sql, $params = []) {
    return db_query($sql, $params)->fetchAll();
}

function db_execute($sql, $params = []) {
    return db_query($sql, $params)->rowCount();
}