<?php
namespace App\Exceptions;

use App\Helpers\Response;
use PDOException;
use Throwable;

/**
 * Class Handler
 * Enterprise Global Exception & Error Handler (OWASP Information Leakage Guard)
 *
 * @package App\Exceptions
 */
class Handler
{
    /**
     * Register Global Exception and Error Handlers
     */
    public static function register(): void
    {
        set_exception_handler([self::class, 'handleException']);
        set_error_handler([self::class, 'handleError']);
        register_shutdown_function([self::class, 'handleShutdown']);
    }

    /**
     * Handle uncaught exceptions
     */
    public static function handleException(Throwable $e): void
    {
        $status = 500;
        $message = "Internal Server Error";
        $details = [];

        if ($e instanceof PDOException) {
            $status = 500;
            $message = "Database Query Error";
            // ในโหมด Debug จะแสดง Error จริง ถ้า Production ซ่อนรายละเอียดป้องกัน SQLi enumeration
            $details = getenv('APP_DEBUG') === 'true' ? ['pdo_error' => $e->getMessage()] : ['info' => 'Please check database logs'];
            error_log("PDOException: " . $e->getMessage() . " in " . $e->getFile() . ":" . $e->getLine());
        } elseif (is_int($e->getCode()) && $e->getCode() >= 400 && $e->getCode() <= 599) {
            $status = $e->getCode();
            $message = $e->getMessage();
        } else {
            $message = $e->getMessage() ?: 'Unexpected Error Occurred';
            error_log("Exception: " . $message . " in " . $e->getFile() . ":" . $e->getLine());
        }

        if (getenv('APP_DEBUG') === 'true') {
            $details['file'] = $e->getFile();
            $details['line'] = $e->getLine();
            $details['trace'] = explode("\n", $e->getTraceAsString());
        }

        if (self::isApiRequest()) {
            Response::error($message, $status, $details);
        } else {
            self::renderHtmlError($status, $message, $details, $e);
        }
    }

    /**
     * Handle PHP Warnings/Notices as Exceptions
     *
     * @param int $level
     * @param string $message
     * @param string $file
     * @param int $line
     * @return bool
     */
    public static function handleError(int $level, string $message, string $file, int $line): bool
    {
        if (!(error_reporting() & $level)) {
            return false;
        }
        error_log("PHP Error [{$level}]: {$message} in {$file}:{$line}");
        return true;
    }

    /**
     * Handle Fatal Errors on shutdown
     */
    public static function handleShutdown(): void
    {
        $error = error_get_last();
        if ($error && in_array($error['type'], [E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR])) {
            error_log("Fatal Shutdown Error: {$error['message']} in {$error['file']}:{$error['line']}");
            if (self::isApiRequest()) {
                Response::error("Fatal Server Error: {$error['message']}", 500);
            } else {
                self::renderHtmlError(500, "Fatal PHP Error: " . $error['message'], ['file' => $error['file'], 'line' => $error['line']]);
            }
        }
    }

    private static function isApiRequest(): bool
    {
        $uri = (string)($_SERVER['REQUEST_URI'] ?? '');
        $accept = (string)($_SERVER['HTTP_ACCEPT'] ?? '');
        return (strpos($uri, '/api/') !== false) || 
               (strpos($uri, 'api=') !== false) || 
               (strpos($uri, 'endpoint=') !== false) || 
               (strpos($accept, 'application/json') !== false) ||
               isset($_GET['api']) || isset($_GET['endpoint']);
    }

    /**
     * Render HTML Error Page
     *
     * @param int $status
     * @param string $message
     * @param array<string, mixed> $details
     * @param Throwable|null $e
     */
    private static function renderHtmlError(int $status, string $message, array $details = [], ?Throwable $e = null): void
    {
        http_response_code($status);
        $debugHtml = '';
        if ((getenv('APP_DEBUG') === 'true' || getenv('APP_ENV') === 'local') && ($details || $e)) {
            $errText = $e ? htmlspecialchars($e->getMessage()) : htmlspecialchars(json_encode($details, JSON_UNESCAPED_UNICODE));
            $errFile = $e ? htmlspecialchars($e->getFile() . ':' . $e->getLine()) : '';
            $debugHtml = "<div class='mt-4 p-4 bg-slate-950/80 rounded-xl text-left border border-rose-500/30 overflow-auto max-h-60 text-xs font-mono text-rose-300'>
                <p class='font-bold underline mb-1'>Debug Information (APP_DEBUG=true):</p>
                <p class='mb-2'><strong>Message:</strong> {$errText}</p>
                " . ($errFile ? "<p class='mb-2'><strong>Location:</strong> {$errFile}</p>" : "") . "
            </div>";
        }
        echo "<!DOCTYPE html>
        <html lang='th'>
        <head>
            <meta charset='UTF-8'>
            <title>Error {$status} - TTMQMS</title>
            <script src='https://cdn.tailwindcss.com'></script>
        </head>
        <body class='bg-slate-900 text-slate-100 flex items-center justify-center min-h-screen font-sans p-4'>
            <div class='bg-slate-800 border border-slate-700 rounded-2xl p-8 max-w-xl w-full text-center shadow-2xl'>
                <div class='text-6xl mb-4'>⚠️</div>
                <h1 class='text-4xl font-bold text-rose-500 mb-2'>{$status}</h1>
                <p class='text-lg text-slate-300 mb-4'>{$message}</p>
                {$debugHtml}
                <div class='mt-6'>
                    <a href='" . (defined('BASE_URL') ? BASE_URL : '') . "/' class='bg-emerald-600 hover:bg-emerald-500 text-white font-medium px-6 py-2.5 rounded-xl transition inline-block'>กลับสู่หน้าหลัก / รีเฟรช</a>
                </div>
            </div>
        </body>
        </html>";
        exit();
    }
}