<?php

if (!defined('ABSPATH')) {
    exit;
}

/**
 * Dispatches unresolved frontend requests to the configured 404 response path.
 */
class ABJ_404_Solution_NotFoundResponseService {

    /** @var ABJ_404_Solution_Functions */
    private $f;

    /** @var ABJ_404_Solution_RedirectsRepositoryInterface */
    private $redirectsRepo;

    /** @var ABJ_404_Solution_LogsRepositoryInterface */
    private $logsRepo;

    /** @var ABJ_404_Solution_Logging */
    private $logger;

    /** @var ABJ_404_Solution_PluginLogicOptionsResolver */
    private $optionsRepository;

    /** @var ABJ_404_Solution_PreviousRequestCookieTracker */
    private $previousRequestCookieTracker;

    /** @var ABJ_404_Solution_RedirectLoopGuard */
    private $loopGuard;

    /** @var ABJ_404_Solution_NearMissRecorder */
    private $nearMissRecorder;

    /**
     * @param ABJ_404_Solution_NotFoundResponseDependencies|null $deps
     */
    function __construct(?ABJ_404_Solution_NotFoundResponseDependencies $deps = null) {
        $deps = $deps ?? new ABJ_404_Solution_NotFoundResponseDependencies();
        $this->f = $deps->functions !== null ? $deps->functions : abj_service('functions');
        $this->redirectsRepo = $deps->redirectsRepo !== null ? $deps->redirectsRepo : abj_service('redirects_repository');
        $this->logsRepo = $deps->logsRepo !== null ? $deps->logsRepo : abj_service('logs_repository');
        $this->logger = $deps->logging !== null ? $deps->logging : abj_service('logging');
        $this->optionsRepository = $deps->optionsRepository !== null ? $deps->optionsRepository : abj_service('options_repository');
        $this->previousRequestCookieTracker = $deps->previousRequestCookieTracker !== null
            ? $deps->previousRequestCookieTracker
            : abj_service('previous_request_cookie_tracker');
        $this->nearMissRecorder = $deps->nearMissRecorder !== null
            ? $deps->nearMissRecorder
            : abj_service('near_miss_recorder');
        $this->loopGuard = new ABJ_404_Solution_RedirectLoopGuard(
            $this->f, $this->logger, $this->previousRequestCookieTracker
        );
    }

    /**
     * @param string $requestedURL
     * @param string $reason
     * @param bool $useUserSpecified404
     * @param array<string, mixed>|null $optionsOverride
     * @return void
     */
    function sendTo404Page(string $requestedURL, string $reason = '', bool $useUserSpecified404 = true, $optionsOverride = null): void {
        $options = (is_array($optionsOverride) ? $optionsOverride : $this->optionsRepository->getOptions());

        $behavior = isset($options['dest404_behavior']) ? $options['dest404_behavior'] : '';
        if ($behavior === 'suggest') {
            $systemPage = ABJ_404_Solution_SystemPage::getInstance();
            if (!$systemPage->systemPageExists()) {
                $systemPage->handleSystemPageDeleted();
                $options = $this->optionsRepository->getOptions(true);
            }
        }

        $dest404pageRaw = isset($options['dest404page']) ? $options['dest404page'] : null;
        $dest404page = is_string($dest404pageRaw) ? $dest404pageRaw : (ABJ404_TYPE_404_DISPLAYED . '|' . ABJ404_TYPE_404_DISPLAYED);

        if ($useUserSpecified404 && $this->thereIsAUserSpecified404Page($dest404page)) {
            $permalink = ABJ_404_Solution_PermalinkResolver::permalinkInfoToArray($dest404page, 0, null, $options);

            if (!in_array($permalink['status'], array('publish', 'published'))) {
                $msg = __("The user specified 404 page wasn't found. " .
                        "Please update the user-specified 404 page on the Options page.",
                        '404-solution');
                $this->logger->infoMessage($msg);

            } else {
                $redirect = $this->redirectsRepo->getExistingRedirectForURL($requestedURL);
                $pType = is_scalar($permalink['type']) ? (string)$permalink['type'] : '';
                $pId = is_scalar($permalink['id']) ? (string)$permalink['id'] : '';
                $pLink = is_scalar($permalink['link']) ? (string)$permalink['link'] : '';
                $defRedir = is_scalar($options['default_redirect']) ? (string)$options['default_redirect'] : '301';
                if (!isset($redirect['id']) || $redirect['id'] == 0) {
                    $this->redirectsRepo->setupRedirect(
                        $this->capturedRedirectSpec(array(
                            'requestedURL' => $requestedURL,
                            'type' => $pType,
                            'finalDest' => $pId,
                            'code' => $defRedir,
                        )));
                }

                $this->logsRepo->logRedirectHit(ABJ_404_Solution_RedirectHitLogEntry::create($requestedURL, $pLink, 'user specified 404 page. ' . $reason));

                setcookie(ABJ404_PP . '_STATUS_404', 'true', abj_clock()->now() + 20, "/");

                $this->forceRedirect(esc_url($pLink), (int)$defRedir);
                exit;
            }
        }

        if (@$options['capture_404'] == '1') {
            $redirect = $this->redirectsRepo->getExistingRedirectForURL($requestedURL);
            $defRedir2 = is_scalar($options['default_redirect']) ? (string)$options['default_redirect'] : '301';
            if (!isset($redirect['id']) || $redirect['id'] == 0) {
                $this->redirectsRepo->setupRedirect($this->capturedRedirectSpec(
                    array(
                        'requestedURL' => $requestedURL,
                        'type' => (string)ABJ404_TYPE_404_DISPLAYED,
                        'finalDest' => (string)ABJ404_TYPE_404_DISPLAYED,
                        'code' => $defRedir2,
                    )));
            }
        } else {
            $optionsJson = json_encode($options);
            $this->logger->debugMessage("No permalink found to redirect to. capture_404 is off. Requested URL: " . $requestedURL .
                    " | Redirect: (none)" . " | is_single(): " . is_single() . " | " .
                    "is_page(): " . is_page() . " | is_feed(): " . is_feed() . " | is_trackback(): " .
                    is_trackback() . " | is_preview(): " . is_preview() . " | options: " . wp_kses_post(is_string($optionsJson) ? $optionsJson : ''));
        }
    }

    /**
     * Build the insert for a captured 404, stamped with the confidence score of
     * the best match the engines found and rejected for this URL.
     *
     * A captured row is not a manual redirect: when automatic matching ran and
     * came close, the score is the one number that tells the admin why the URL
     * was captured rather than redirected, and the Captured tab has had a
     * Confidence column, a badge template and two covering indexes waiting for
     * it. When no near miss was recorded -- automatic matching is off, or
     * nothing scored at all -- score and engine stay null, which is the honest
     * answer and what the Score column's no-score branch renders.
     *
     * @param array{requestedURL: string, type: string, finalDest: string, code: string} $fields
     * @return ABJ_404_Solution_RedirectSpec
     */
    private function capturedRedirectSpec(array $fields): ABJ_404_Solution_RedirectSpec {
        $nearMiss = $this->nearMissRecorder->getBestFor($fields['requestedURL']);

        return ABJ_404_Solution_RedirectSpec::fromArray(array(
            'fromURL' => $fields['requestedURL'],
            'status' => (string)ABJ404_STATUS_CAPTURED,
            'type' => $fields['type'],
            'finalDest' => $fields['finalDest'],
            'code' => $fields['code'],
            'disabled' => 0,
            'engine' => $nearMiss !== null ? $nearMiss->getEngineName() : null,
            'score' => $nearMiss !== null ? $nearMiss->getScore() : null,
        ));
    }

    /** @param string|null $dest404page @return bool */
    function thereIsAUserSpecified404Page($dest404page): bool {
        if ($dest404page == null) {
            return false;
        }
        $check1 = ($dest404page !== (ABJ404_TYPE_404_DISPLAYED . '|' . ABJ404_TYPE_404_DISPLAYED));
        $check2 = ($dest404page !== (string)ABJ404_TYPE_404_DISPLAYED);
        return $check1 && $check2;
    }

    /** @return string */
    function getCommentPartAndQueryPartOfRequest() {
        $requestUri = isset($_SERVER['REQUEST_URI']) && is_string($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '';
        if ($requestUri !== '' &&
                strpos($requestUri, '?') === false &&
                strpos($requestUri, '/comment-page-') === false) {
            return '';
        }

        $userRequest = ABJ_404_Solution_UserRequest::getInstance();
        if ($userRequest === null) {
            return '';
        }
        $queryString = $userRequest->getQueryString();
        $queryParts = abj_service('query_string_helper')->removePageIDFromQueryString(is_string($queryString) ? $queryString : '');
        $queryParts = ($queryParts == '') ? '' : '?' . $queryParts;
        $commentPart = $userRequest->getCommentPagePart();
        return (is_string($commentPart) ? $commentPart : '') . $queryParts;
    }

    /**
     * @param string $location
     * @param int $status
     * @param int|string $type only 0 for sending to a 404 page
     * @param string $requestedURL
     * @param bool $isCustom404
     * @return bool true if the user is sent to the default 404 page.
     */
    function forceRedirect(string $location, int $status = 302, $type = -1, string $requestedURL = '', bool $isCustom404 = false): bool {
        if ($status === 410) {
            $this->sendGoneStatusResponse(
                410,
                'gone410.html',
                esc_html__('This content has been permanently removed.', '404-solution'),
                esc_html__('The page you requested no longer exists and has not been moved to a new location.', '404-solution')
            );
        }

        if ($status === 451) {
            $this->sendGoneStatusResponse(
                451,
                'gone451.html',
                esc_html__('451 Unavailable For Legal Reasons', '404-solution'),
                esc_html__('This content is unavailable due to a legal demand.', '404-solution')
            );
        }

        if ($status === 0 && $location !== '') {
            $this->sendMetaRefreshResponse($location);
        }

        $pluginLogic = abj_service('plugin_logic');
        if (is_object($pluginLogic) && method_exists($pluginLogic, 'pageOrdering')) {
            $finalDestination = $pluginLogic->pageOrdering()
                ->buildFinalRedirectDestination($location, $requestedURL, $isCustom404);
        } else {
            $finalDestination = (string)$location . $this->getCommentPartAndQueryPartOfRequest();
        }

        $terminatingDestination = $this->loopGuard->terminatingDestination(array(
            'finalDestination' => $finalDestination,
            'location' => $location,
        ));
        if ($terminatingDestination === false) {
            return false;
        }
        $finalDestination = $terminatingDestination;

        if ($type == ABJ404_TYPE_404_DISPLAYED) {
            $this->sendTo404Page($requestedURL, '', false);
            return true;
        }

        if (is_object($this->previousRequestCookieTracker)) {
            $this->previousRequestCookieTracker->setCookieWithPreviousRequest();
        }
        if (!headers_sent()) {
            return $this->sendHeaderRedirect($finalDestination, $status);
        }

        return $this->sendJavaScriptRedirectFallback($finalDestination);
    }

    private function sendGoneStatusResponse(int $status, string $templateFile, string $heading, string $message): void {
        status_header($status);
        $templatePath = dirname(__DIR__) . '/html/' . $templateFile;
        if (file_exists($templatePath)) {
            $siteName = function_exists('get_bloginfo') ? get_bloginfo('name') : '';
            $siteUrl  = function_exists('home_url') ? home_url('/') : '/';
            $templateContent = file_get_contents($templatePath);
            if (is_string($templateContent)) {
                echo str_replace(
                    array('{site_name}', '{site_url}', '{heading}', '{message}', '{back_home}'),
                    array(
                        esc_html($siteName),
                        esc_url($siteUrl),
                        $heading,
                        $message,
                        esc_html__('Back to home page', '404-solution'),
                    ),
                    $templateContent
                );
            }
        }
        exit;
    }

    private function sendMetaRefreshResponse(string $location): void {
        status_header(200);
        $templatePath = dirname(__DIR__) . '/html/metaRefresh.html';
        if (file_exists($templatePath)) {
            $templateContent = file_get_contents($templatePath);
            if (is_string($templateContent)) {
                echo str_replace(
                    array('{url}', '{delay}', '{title}', '{message}'),
                    array(
                        esc_url($location),
                        '0',
                        esc_html__('Redirecting...', '404-solution'),
                        esc_html__('You are being redirected. Click the link if not redirected automatically.', '404-solution'),
                    ),
                    $templateContent
                );
            }
        }
        exit;
    }

    private function sendHeaderRedirect(string $finalDestination, int $status): bool {
        if (function_exists('abj404_benchmark_emit_headers')) {
            try {
                abj404_benchmark_emit_headers();
            } catch (Throwable $e) {
                $this->warnBenchmarkHeaderFailure($e);
            }
        }

        $allowedRedirectHostFilter = $this->addAllowedRedirectHostFilter($finalDestination);
        wp_safe_redirect($finalDestination, $status, ABJ404_NAME);
        if ($allowedRedirectHostFilter !== null) {
            remove_filter('allowed_redirect_hosts', $allowedRedirectHostFilter, 10);
        }
        if (!apply_filters('abj404_should_exit', true, array('source' => 'forceRedirect_header'))) {
            return false;
        }
        exit;
    }

    private function addAllowedRedirectHostFilter(string $finalDestination): ?callable {
        $destHost = parse_url($finalDestination, PHP_URL_HOST);
        if (!is_string($destHost) || $destHost === '') {
            return null;
        }

        $allowedRedirectHostFilter = static function($hosts) use ($destHost) {
            $normalizedHosts = array();
            if (is_array($hosts)) {
                foreach ($hosts as $host) {
                    if (is_scalar($host) || $host === null || (is_object($host) && method_exists($host, '__toString'))) {
                        $normalizedHosts[] = (string)$host;
                    }
                }
            }
            $normalizedHosts[] = strtolower($destHost);
            return array_values(array_unique($normalizedHosts));
        };
        add_filter('allowed_redirect_hosts', $allowedRedirectHostFilter, 10, 1);

        return $allowedRedirectHostFilter;
    }

    private function sendJavaScriptRedirectFallback(string $finalDestination): bool {
        if (function_exists('abj404_benchmark_emit_headers')) {
            abj404_benchmark_emit_headers();
        }
        $template = ABJ_404_Solution_FileSystemService::readFileContents(
            dirname(__DIR__) . '/html/notFoundRedirectFallback.html',
            false
        );
        echo $this->f->str_replace(
            array('{destination_json}', '{destination_url}', '{destination_label}'),
            array((string)wp_json_encode($finalDestination), esc_url($finalDestination), esc_html($finalDestination)),
            $template
        );
        if (!apply_filters('abj404_should_exit', true, array('source' => 'forceRedirect_js'))) {
            return false;
        }
        exit;
    }

    private function warnBenchmarkHeaderFailure(Throwable $e): void {
        $message = 'abj404_benchmark_emit_headers failed: ' . $e->getMessage();
        if (is_object($this->logger) && method_exists($this->logger, 'warn')) {
            $this->logger->warn($message);
            return;
        }

        abj404_logPhpFallback('service-resolution-fallback', $message);
    }

}