bootstrap.php

<?php
/**
 * Bootstrap File
 *
 * Initializes the application:
 * - Loads environment variables from .env
 * - Registers autoloader
 * - Loads configuration
 * - Starts session
 * - Sets up error handling
 */

/**
 * Autoloader (must be first to load DotEnv class)
 *
 * Automatically loads classes using PSR-4 naming convention.
 * Maps App\* namespace to app/* directory.
 */
spl_autoload_register(function ($class) {
    // Base directory for the namespace prefix
    $baseDir = __DIR__ . '/app/';

    // Convert namespace to file path
    // App\Core\Database => app/Core/Database.php
    // App\Models\Employee => app/Models/Employee.php
    $file = $baseDir . str_replace('App\\', '', $class) . '.php';
    $file = str_replace('\\', DIRECTORY_SEPARATOR, $file);

    // If the file exists, require it
    if (file_exists($file)) {
        require_once $file;
    }
});

// Load environment variables from .env file
App\Core\DotEnv::load(__DIR__);

// Load configuration
require_once __DIR__ . '/config/config.php';

// Configure secure session settings for production
if (APP_ENV === 'production') {
    ini_set('session.cookie_httponly', 1); // Prevent JavaScript access to session cookie
    ini_set('session.cookie_secure', 1);   // Only send cookie over HTTPS
    ini_set('session.use_strict_mode', 1); // Reject uninitialized session IDs
    ini_set('session.cookie_samesite', 'Strict'); // CSRF protection
}

// Start session with custom name
session_name(SESSION_NAME);
session_start();

// Regenerate session ID on login to prevent session fixation
if (!isset($_SESSION['initiated'])) {
    session_regenerate_id(true);
    $_SESSION['initiated'] = true;
}

/**
 * Load Helper Files
 *
 * Helper files contain global functions that need to be explicitly loaded
 */
require_once __DIR__ . '/app/Helpers/DateHelper.php';
require_once __DIR__ . '/app/Helpers/SecurityHelper.php';

/**
 * Error Handler
 *
 * Custom error handling for better debugging
 */
if (DEBUG_MODE) {
    // Development mode - show all errors
    set_error_handler(function ($errno, $errstr, $errfile, $errline) {
        throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
    });
} else {
    // Production mode - log errors, don't display
    set_error_handler(function ($errno, $errstr, $errfile, $errline) {
        error_log("Error [$errno]: $errstr in $errfile on line $errline");
        return true; // Don't execute PHP's internal error handler
    });
}

/**
 * Exception Handler
 *
 * Handle uncaught exceptions gracefully
 */
set_exception_handler(function ($exception) {
    error_log("Uncaught exception: " . $exception->getMessage());

    if (DEBUG_MODE) {
        // Development - show detailed error
        echo "<div style='background: #f8d7da; border: 1px solid #f5c6cb; color: #721c24; padding: 20px; margin: 20px; border-radius: 5px;'>";
        echo "<h2>An error occurred:</h2>";
        echo "<p><strong>Message:</strong> " . $exception->getMessage() . "</p>";
        echo "<p><strong>File:</strong> " . $exception->getFile() . " (Line " . $exception->getLine() . ")</p>";
        echo "<pre>" . $exception->getTraceAsString() . "</pre>";
        echo "</div>";
    } else {
        // Production - show generic error
        echo "<div style='background: #f8d7da; border: 1px solid #f5c6cb; color: #721c24; padding: 20px; margin: 20px; border-radius: 5px;'>";
        echo "<h2>An error occurred</h2>";
        echo "<p>We're sorry, but something went wrong. Please try again later or contact the system administrator.</p>";
        echo "</div>";
    }
});

/**
 * Helper Functions
 *
 * Global helper functions available throughout the application
 * Wrapped in function_exists() to avoid conflicts with other packages
 */

/**
 * Dump and die - for debugging
 *
 * @param mixed ...$vars Variables to dump
 */
if (!function_exists('dd')) {
    function dd(...$vars)
    {
        echo "<pre style='background: #f8f9fa; border: 2px solid #dee2e6; padding: 15px; margin: 10px; border-radius: 5px;'>";
        foreach ($vars as $var) {
            var_dump($var);
        }
        echo "</pre>";
        die();
    }
}

/**
 * Get the root URL of the application
 *
 * @param string $path Optional path to append
 * @return string
 */
if (!function_exists('url')) {
    function url($path = '')
    {
        return APP_URL . '/' . ltrim($path, '/');
    }
}

/**
 * Get asset URL
 *
 * @param string $path Path to asset
 * @return string
 */
if (!function_exists('asset')) {
    function asset($path)
    {
        return APP_URL . '/assets/' . ltrim($path, '/');
    }
}

/**
 * Redirect to a URL
 *
 * @param string $url URL to redirect to
 */
if (!function_exists('redirect')) {
    function redirect($url)
    {
        header("Location: {$url}");
        exit;
    }
}

/**
 * Redirect back to previous page
 */
if (!function_exists('back')) {
    function back()
    {
        redirect($_SERVER['HTTP_REFERER'] ?? 'index.php');
    }
}

/**
 * Get current page filename
 *
 * @return string
 */
if (!function_exists('currentPage')) {
    function currentPage()
    {
        return basename($_SERVER['PHP_SELF']);
    }
}

/**
 * Check if on specific page
 *
 * @param string $page Page filename
 * @return bool
 */
if (!function_exists('isPage')) {
    function isPage($page)
    {
        return currentPage() === $page;
    }
}

// Application initialized