<?php
/**
 * Centralized Error Handler
 *
 * Provides consistent error handling, logging, and response formatting
 * across the application.
 */
class ErrorHandler {
    private static ?string $logFile = null;
    private static bool $initialized = false;

    /**
     * Initialize error handling
     *
     * @param bool $displayErrors Whether to display errors (false in production)
     */
    public static function init(bool $displayErrors = false): void {
        if (self::$initialized) {
            return;
        }

        // Set error reporting
        error_reporting(E_ALL);
        ini_set('display_errors', $displayErrors ? '1' : '0');
        ini_set('log_errors', '1');

        // Set up log file
        self::$logFile = sys_get_temp_dir() . '/tinker_tickets_errors.log';
        ini_set('error_log', self::$logFile);

        // Register handlers
        set_error_handler([self::class, 'handleError']);
        set_exception_handler([self::class, 'handleException']);
        register_shutdown_function([self::class, 'handleShutdown']);

        self::$initialized = true;
    }

    /**
     * Handle PHP errors
     *
     * @param int $errno Error level
     * @param string $errstr Error message
     * @param string $errfile File where error occurred
     * @param int $errline Line number
     * @return bool
     */
    public static function handleError(int $errno, string $errstr, string $errfile, int $errline): bool {
        // Don't handle suppressed errors
        if (!(error_reporting() & $errno)) {
            return false;
        }

        $errorType = self::getErrorTypeName($errno);
        $message = "$errorType: $errstr in $errfile on line $errline";

        self::log($message, $errno);

        // For fatal errors, throw exception
        if (in_array($errno, [E_ERROR, E_USER_ERROR, E_RECOVERABLE_ERROR])) {
            throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
        }

        return true;
    }

    /**
     * Handle uncaught exceptions
     *
     * @param Throwable $exception
     */
    public static function handleException(Throwable $exception): void {
        $message = sprintf(
            "Uncaught %s: %s in %s on line %d\nStack trace:\n%s",
            get_class($exception),
            $exception->getMessage(),
            $exception->getFile(),
            $exception->getLine(),
            $exception->getTraceAsString()
        );

        self::log($message, E_ERROR);

        // Send error response if headers not sent
        if (!headers_sent()) {
            self::sendErrorResponse(
                'An unexpected error occurred',
                500,
                $exception
            );
        }
    }

    /**
     * Handle fatal errors on shutdown
     */
    public static function handleShutdown(): void {
        $error = error_get_last();

        if ($error !== null && in_array($error['type'], [E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR])) {
            $message = sprintf(
                "Fatal Error: %s in %s on line %d",
                $error['message'],
                $error['file'],
                $error['line']
            );

            self::log($message, E_ERROR);

            if (!headers_sent()) {
                self::sendErrorResponse('A fatal error occurred', 500);
            }
        }
    }

    /**
     * Log an error message
     *
     * @param string $message Error message
     * @param int $level Error level
     * @param array $context Additional context
     */
    public static function log(string $message, int $level = E_USER_NOTICE, array $context = []): void {
        $timestamp = date('Y-m-d H:i:s');
        $levelName = self::getErrorTypeName($level);

        $logMessage = "[$timestamp] [$levelName] $message";

        if (!empty($context)) {
            $logMessage .= " | Context: " . json_encode($context);
        }

        error_log($logMessage);
    }

    /**
     * Send a JSON error response
     *
     * @param string $message User-facing error message
     * @param int $httpCode HTTP status code
     * @param Throwable|null $exception Original exception (for debug info)
     */
    public static function sendErrorResponse(string $message, int $httpCode = 500, ?Throwable $exception = null): void {
        http_response_code($httpCode);

        if (!headers_sent()) {
            header('Content-Type: application/json');
        }

        $response = [
            'success' => false,
            'error' => $message
        ];

        // Add debug info in development (check for debug mode)
        if (isset($GLOBALS['config']['DEBUG']) && $GLOBALS['config']['DEBUG'] && $exception) {
            $response['debug'] = [
                'type' => get_class($exception),
                'message' => $exception->getMessage(),
                'file' => $exception->getFile(),
                'line' => $exception->getLine()
            ];
        }

        echo json_encode($response);
        exit;
    }

    /**
     * Send a validation error response
     *
     * @param array $errors Array of validation errors
     * @param string $message Overall error message
     */
    public static function sendValidationError(array $errors, string $message = 'Validation failed'): void {
        http_response_code(422);

        if (!headers_sent()) {
            header('Content-Type: application/json');
        }

        echo json_encode([
            'success' => false,
            'error' => $message,
            'validation_errors' => $errors
        ]);
        exit;
    }

    /**
     * Send a not found error response
     *
     * @param string $message Error message
     */
    public static function sendNotFoundError(string $message = 'Resource not found'): void {
        self::sendErrorResponse($message, 404);
    }

    /**
     * Send an unauthorized error response
     *
     * @param string $message Error message
     */
    public static function sendUnauthorizedError(string $message = 'Authentication required'): void {
        self::sendErrorResponse($message, 401);
    }

    /**
     * Send a forbidden error response
     *
     * @param string $message Error message
     */
    public static function sendForbiddenError(string $message = 'Access denied'): void {
        self::sendErrorResponse($message, 403);
    }

    /**
     * Get error type name from error number
     *
     * @param int $errno Error number
     * @return string Error type name
     */
    private static function getErrorTypeName(int $errno): string {
        $types = [
            E_ERROR => 'ERROR',
            E_WARNING => 'WARNING',
            E_PARSE => 'PARSE',
            E_NOTICE => 'NOTICE',
            E_CORE_ERROR => 'CORE_ERROR',
            E_CORE_WARNING => 'CORE_WARNING',
            E_COMPILE_ERROR => 'COMPILE_ERROR',
            E_COMPILE_WARNING => 'COMPILE_WARNING',
            E_USER_ERROR => 'USER_ERROR',
            E_USER_WARNING => 'USER_WARNING',
            E_USER_NOTICE => 'USER_NOTICE',
            E_STRICT => 'STRICT',
            E_RECOVERABLE_ERROR => 'RECOVERABLE_ERROR',
            E_DEPRECATED => 'DEPRECATED',
            E_USER_DEPRECATED => 'USER_DEPRECATED',
        ];

        return $types[$errno] ?? 'UNKNOWN';
    }

    /**
     * Get recent error log entries
     *
     * @param int $lines Number of lines to return
     * @return array Log entries
     */
    public static function getRecentErrors(int $lines = 50): array {
        if (self::$logFile === null || !file_exists(self::$logFile)) {
            return [];
        }

        $file = file(self::$logFile);
        if ($file === false) {
            return [];
        }

        return array_slice($file, -$lines);
    }
}