config.example.php

<?php
/**
 * E-Learning Platform Configuration
 * 
 * This file contains all configuration settings for the application.
 * Copy this to config.php and modify as needed.
 */

// Environment Configuration
define('APP_ENV', $_ENV['APP_ENV'] ?? 'development'); // development, staging, production
define('APP_DEBUG', APP_ENV === 'development');
define('APP_URL', $_ENV['APP_URL'] ?? 'http://localhost');

// Database Configuration
define('DB_HOST', $_ENV['DB_HOST'] ?? 'localhost');
define('DB_USERNAME', $_ENV['DB_USERNAME'] ?? 'root');
define('DB_PASSWORD', $_ENV['DB_PASSWORD'] ?? '');
define('DB_NAME', $_ENV['DB_NAME'] ?? 'elearning');
define('DB_CHARSET', 'utf8mb4');

// Application Settings
define('SITE_NAME', 'E-Learning Platform');
define('SITE_DESCRIPTION', 'Comprehensive online learning management system');
define('SITE_KEYWORDS', 'e-learning, education, courses, online learning');
define('ADMIN_EMAIL', $_ENV['ADMIN_EMAIL'] ?? 'admin@example.com');

// File Upload Settings
define('UPLOAD_MAX_SIZE', 10 * 1024 * 1024); // 10MB
define('UPLOAD_PATH', 'admin/images/');
define('ALLOWED_EXTENSIONS', ['jpg', 'jpeg', 'png', 'gif', 'pdf', 'doc', 'docx']);

// Security Settings
define('SESSION_LIFETIME', 3600); // 1 hour
define('HASH_ALGORITHM', 'sha256');
define('ENCRYPTION_KEY', $_ENV['ENCRYPTION_KEY'] ?? 'your-secret-key-here');

// Email Configuration
define('MAIL_HOST', $_ENV['MAIL_HOST'] ?? 'smtp.gmail.com');
define('MAIL_PORT', $_ENV['MAIL_PORT'] ?? 587);
define('MAIL_USERNAME', $_ENV['MAIL_USERNAME'] ?? '');
define('MAIL_PASSWORD', $_ENV['MAIL_PASSWORD'] ?? '');
define('MAIL_ENCRYPTION', 'tls');
define('MAIL_FROM_ADDRESS', $_ENV['MAIL_FROM_ADDRESS'] ?? ADMIN_EMAIL);
define('MAIL_FROM_NAME', $_ENV['MAIL_FROM_NAME'] ?? SITE_NAME);

// Pagination Settings
define('POSTS_PER_PAGE', 10);
define('SEARCH_RESULTS_PER_PAGE', 15);

// Cache Settings
define('CACHE_ENABLED', APP_ENV === 'production');
define('CACHE_DURATION', 3600); // 1 hour

// API Settings
define('API_ENABLED', true);
define('API_RATE_LIMIT', 100); // requests per hour
define('API_KEY_REQUIRED', APP_ENV === 'production');

// Social Media Links
define('FACEBOOK_URL', $_ENV['FACEBOOK_URL'] ?? '');
define('TWITTER_URL', $_ENV['TWITTER_URL'] ?? '');
define('LINKEDIN_URL', $_ENV['LINKEDIN_URL'] ?? '');
define('YOUTUBE_URL', $_ENV['YOUTUBE_URL'] ?? '');

// Google Analytics
define('GA_TRACKING_ID', $_ENV['GA_TRACKING_ID'] ?? '');

// reCAPTCHA
define('RECAPTCHA_SITE_KEY', $_ENV['RECAPTCHA_SITE_KEY'] ?? '');
define('RECAPTCHA_SECRET_KEY', $_ENV['RECAPTCHA_SECRET_KEY'] ?? '');

// Error Reporting
if (APP_DEBUG) {
    error_reporting(E_ALL);
    ini_set('display_errors', 1);
} else {
    error_reporting(0);
    ini_set('display_errors', 0);
    ini_set('log_errors', 1);
    ini_set('error_log', 'logs/error.log');
}

// Timezone
date_default_timezone_set($_ENV['TIMEZONE'] ?? 'UTC');

// Function to load environment variables from .env file
function loadEnvFile($file = '.env') {
    if (!file_exists($file)) {
        return;
    }
    
    $lines = file($file, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
    foreach ($lines as $line) {
        if (strpos($line, '=') !== false && strpos($line, '#') !== 0) {
            list($key, $value) = explode('=', $line, 2);
            $key = trim($key);
            $value = trim($value);
            
            // Remove quotes if present
            if (preg_match('/^(["\'])(.*)\\1$/', $value, $matches)) {
                $value = $matches[2];
            }
            
            $_ENV[$key] = $value;
            putenv("$key=$value");
        }
    }
}

// Load environment variables
loadEnvFile();

// Database Connection Function
function getDatabaseConnection() {
    static $connection = null;
    
    if ($connection === null) {
        $connection = mysqli_connect(DB_HOST, DB_USERNAME, DB_PASSWORD, DB_NAME);
        
        if (!$connection) {
            if (APP_DEBUG) {
                die('Database connection failed: ' . mysqli_connect_error());
            } else {
                die('Database connection failed. Please try again later.');
            }
        }
        
        mysqli_set_charset($connection, DB_CHARSET);
    }
    
    return $connection;
}

// Utility Functions
function sanitizeInput($data) {
    $data = trim($data);
    $data = stripslashes($data);
    $data = htmlspecialchars($data);
    return $data;
}

function isValidEmail($email) {
    return filter_var($email, FILTER_VALIDATE_EMAIL);
}

function generateSecureToken($length = 32) {
    return bin2hex(random_bytes($length));
}

function hashPassword($password) {
    return password_hash($password, PASSWORD_DEFAULT);
}

function verifyPassword($password, $hash) {
    return password_verify($password, $hash);
}

function logError($message, $file = 'error.log') {
    $timestamp = date('Y-m-d H:i:s');
    $logMessage = "[$timestamp] $message" . PHP_EOL;
    error_log($logMessage, 3, "logs/$file");
}

function redirectTo($url) {
    header("Location: $url");
    exit();
}

function isLoggedIn() {
    return isset($_SESSION['user_id']);
}

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

function getCurrentUser() {
    if (isLoggedIn()) {
        return [
            'id' => $_SESSION['user_id'],
            'email' => $_SESSION['user_email'],
            'role' => $_SESSION['user_role']
        ];
    }
    return null;
}

// Start session if not already started
if (session_status() === PHP_SESSION_NONE) {
    session_start();
}

// Set session configuration
ini_set('session.cookie_httponly', 1);
ini_set('session.cookie_secure', APP_ENV === 'production' ? 1 : 0);
ini_set('session.use_strict_mode', 1);

?>