<?php
session_start();

$db_host = 'localhost';
$db_user = 'root'; // Change if needed
$db_pass = '@Samui@10742';     // Change if needed
$db_name = 'student_assignment_notify';

try {
    $pdo = new PDO("mysql:host=$db_host;dbname=$db_name;charset=utf8mb4", $db_user, $db_pass);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);

    $pdo->exec("CREATE TABLE IF NOT EXISTS settings (
        setting_key VARCHAR(50) PRIMARY KEY,
        setting_value TEXT
    )");
    
    $pdo->exec("CREATE TABLE IF NOT EXISTS activity_logs (
        id INT AUTO_INCREMENT PRIMARY KEY,
        user_id INT NULL,
        action VARCHAR(100) NOT NULL,
        details TEXT,
        ip_address VARCHAR(45),
        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4");

} catch (PDOException $e) {
    die("Database Connection failed: " . $e->getMessage());
}

// Helper function to get setting
function getSetting($pdo, $key)
{
    $stmt = $pdo->prepare("SELECT setting_value FROM settings WHERE setting_key = ?");
    $stmt->execute([$key]);
    $result = $stmt->fetch();
    return $result ? $result['setting_value'] : null;
}

// Helper function to log activity
function logActivity($pdo, $action, $details = '')
{
    $user_id = $_SESSION['user_id'] ?? null;
    $ip_address = $_SERVER['REMOTE_ADDR'] ?? 'Unknown';
    
    try {
        $stmt = $pdo->prepare("INSERT INTO activity_logs (user_id, action, details, ip_address) VALUES (?, ?, ?, ?)");
        $stmt->execute([$user_id, $action, $details, $ip_address]);
    } catch (PDOException $e) {
        // Silently ignore log insertion errors to prevent breaking the app
    }
}

// Helper function to check login
function isLoggedIn()
{
    return isset($_SESSION['user_id']);
}

function requireLogin()
{
    if (!isLoggedIn()) {
        header('Location: index.php');
        exit;
    }
}

function isAdmin()
{
    return isset($_SESSION['role']) && $_SESSION['role'] === 'admin';
}

function requireAdmin()
{
    if (!isAdmin()) {
        die("Unauthorized access.");
    }
}