<?php
/**
 * @author Giancarlo Voci
 * @date 25/06/2018
 * @time 16:14
 */

namespace OpenMind\System;

use Base;

class ErrorHandlers
{
	private const API_PATH_PREFIX = '/api/v1';
	private const JSON_CONTENT_TYPE = 'application/json; charset=utf-8';
	private const LOG_DATE_FORMAT = 'd/m/Y H:i:s';

	private Base $f3;

	/**
	 * Initializes the error handler with the current framework instance.
	 *
	 * @return void
	 * @sideEffects Reads the framework singleton.
	 */
	public function __construct()
	{
		$this->f3 = Base::instance();
	}

	/**
	 * Renders an application error in the response format for the request type.
	 *
	 * @return null Always returns null for PHP/F3 requests after writing JSON.
	 * @sideEffects Clears output buffers, writes a log entry, and renders or exits.
	 */
	public function Handler()
	{
		$error = $this->f3->get('ERROR');
		$errorValues = [$error['code'], $error['status'], $error['text']];

		while (ob_get_level() > 0) {
			ob_end_clean();
		}

		$this->writeLog(implode(' - ', $errorValues));

		if ($this->f3->get('CLI')) {
			print_r($errorValues);
			exit(1);
		}

		if ($this->isApiRequest()) {
			$this->f3->status((int) $error['code']);
		}

		header('Content-Type: ' . self::JSON_CONTENT_TYPE);
		echo json_encode(['error' => $error['text']], JSON_THROW_ON_ERROR);
		return null;
	}

	/**
	 * Determine whether the current request belongs to the versioned API.
	 *
	 * @return bool True when the request path is rooted at /api/v1.
	 * @sideEffects Reads the current request URI from the framework.
	 */
	private function isApiRequest(): bool
	{
		$uri = $this->f3->get('URI');
		if (!is_string($uri)) {
			return false;
		}

		$path = parse_url($uri, PHP_URL_PATH);
		$basePath = $this->f3->get('BASE');
		if (is_string($path) && is_string($basePath)) {
			$basePath = rtrim($basePath, '/');
			if ($basePath !== '' && $basePath !== '/'
				&& ($path === $basePath || str_starts_with($path, $basePath . '/'))) {
				$path = substr($path, strlen($basePath)) ?: '/';
			}
		}

		return is_string($path)
			&& ($path === self::API_PATH_PREFIX
				|| str_starts_with($path, self::API_PATH_PREFIX . '/'));
	}

	/**
	 * Writes an error message with the relevant caller context.
	 *
	 * @param string $message Error message.
	 * @param int $traceIndex Caller index in the debug trace.
	 * @return void
	 * @sideEffects Writes to the application log.
	 */
	private function writeLog(string $message, int $traceIndex = 1): void
	{
		$trace = debug_backtrace();
		$context = $trace[$traceIndex] ?? [];
		$prefix = ($context['line'] ?? '') . ':'
			. ($context['class'] ?? '') . ':'
			. ($context['function'] ?? '') . ':';
		$sanitizedMessage = str_replace(["\r", "\n"], '', $message);

		OMUtils::getInstance()->getLogger()->write(
			"{$prefix} {$sanitizedMessage}",
			self::LOG_DATE_FORMAT,
		);
	}
}