<?php

use ComboStrap\CacheManager;
use ComboStrap\CacheMedia;
use ComboStrap\DokuPath;
use ComboStrap\Http;
use ComboStrap\Iso8601Date;
use ComboStrap\PluginUtility;
use dokuwiki\Cache\CacheRenderer;
use dokuwiki\Utf8\PhpString;

require_once(__DIR__ . '/../ComboStrap/PluginUtility.php');

/**
 * Can we use the parser cache
 */
class action_plugin_combo_cache extends DokuWiki_Action_Plugin
{
    const COMBO_CACHE_PREFIX = "combo:cache:";

    /**
     * https://www.ietf.org/rfc/rfc2616.txt
     * To mark a response as "never expires," an origin server sends an Expires date approximately one year
     * from the time the response is sent.
     * HTTP/1.1 servers SHOULD NOT send Expires dates more than one year in the future.
     *
     * In seconds = 365*24*60*60
     */
    const INFINITE_MAX_AGE = 31536000;

    /**
     * Enable an infinite cache on image URL with the {@link CacheMedia::CACHE_BUSTER_KEY}
     * present
     */
    const CONF_STATIC_CACHE_ENABLED = "staticCacheEnabled";
    const CANONICAL = "cache";
    const STATIC_SCRIPT_NAMES = ["/lib/exe/jquery.php", "/lib/exe/js.php", "/lib/exe/css.php"];

    /**
     * @param Doku_Event_Handler $controller
     */
    function register(Doku_Event_Handler $controller)
    {

        /**
         * Log the cache usage and also
         */
        $controller->register_hook('PARSER_CACHE_USE', 'AFTER', $this, 'logCacheUsage', array());

        $controller->register_hook('PARSER_CACHE_USE', 'BEFORE', $this, 'purgeIfNeeded', array());

        /**
         * Control the HTTP cache of the image
         */
        $controller->register_hook('MEDIA_SENDFILE', 'BEFORE', $this, 'imageHTTPCacheBefore', array());

        /**
         * To add the cache result in the header
         */
        $controller->register_hook('TPL_METAHEADER_OUTPUT', 'BEFORE', $this, 'addMeta', array());

        /**
         * To reset the cache manager
         * between two run in the test
         */
        $controller->register_hook('DOKUWIKI_DONE', 'BEFORE', $this, 'close', array());

        /**
         * To delete the VARY on css.php, jquery.php, js.php
         */
        $controller->register_hook('INIT_LANG_LOAD', 'BEFORE', $this, 'deleteVaryFromStaticGeneratedResources', array());


    }

    /**
     *
     * @param Doku_Event $event
     * @param $params
     */
    function logCacheUsage(Doku_Event $event, $params)
    {

        /**
         * To log the cache used by bar
         * @var \dokuwiki\Cache\CacheParser $data
         */
        $data = $event->data;
        $result = $event->result;
        $pageId = $data->page;
        $cacheManager = PluginUtility::getCacheManager();
        $cacheManager->addSlot($pageId, $result, $data);


    }

    /**
     *
     * @param Doku_Event $event
     * @param $params
     */
    function purgeIfNeeded(Doku_Event $event, $params)
    {

        /**
         * No cache for all mode
         * (ie xhtml, instruction)
         */
        $data = &$event->data;
        $pageId = $data->page;

        /**
         * For whatever reason, the cache file of XHMTL
         * may be empty - No error found on the web server or the log.
         *
         * We just delete it then.
         *
         * It has been seen after the creation of a new page or a `move` of the page.
         */
        if ($data instanceof CacheRenderer) {
            if ($data->mode === "xhtml") {
                if (file_exists($data->cache)) {
                    if (filesize($data->cache) === 0) {
                        $data->depends["purge"] = true;
                    }
                }
            }
        }
        /**
         * Because of the recursive nature of rendering
         * inside dokuwiki, we just handle the first
         * rendering for a request.
         *
         * The first will be purged, the other one not
         * because they can use the first one
         */
        if (!PluginUtility::getCacheManager()->isCacheLogPresent($pageId, $data->mode)) {
            $expirationStringDate = p_get_metadata($pageId, CacheManager::DATE_CACHE_EXPIRATION_META_KEY, METADATA_DONT_RENDER);
            if ($expirationStringDate !== null) {

                $expirationDate = Iso8601Date::create($expirationStringDate)->getDateTime();
                $actualDate = new DateTime();
                if ($expirationDate < $actualDate) {
                    /**
                     * As seen in {@link Cache::makeDefaultCacheDecision()}
                     * We request a purge
                     */
                    $data->depends["purge"] = true;
                }
            }
        }


    }

    /**
     * Add HTML meta to be able to debug
     * @param Doku_Event $event
     * @param $params
     */
    function addMeta(Doku_Event $event, $params)
    {

        $cacheManager = PluginUtility::getCacheManager();
        $slots = $cacheManager->getCacheSlotResults();
        foreach ($slots as $slotId => $modes) {

            $cachedMode = [];
            foreach ($modes as $mode => $values) {
                if ($values[CacheManager::RESULT_STATUS] === true) {
                    $metaContentData = $mode;
                    if (!PluginUtility::isTest()) {
                        /**
                         * @var DateTime $dateModified
                         */
                        $dateModified = $values[CacheManager::DATE_MODIFIED];
                        $metaContentData .= ":" . $dateModified->format('Y-m-d\TH:i:s');
                    }
                    $cachedMode[] = $metaContentData;
                }
            }

            if (sizeof($cachedMode) === 0) {
                $value = "nocache";
            } else {
                sort($cachedMode);
                $value = implode(",", $cachedMode);
            }

            // Add cache information into the head meta
            // to test
            $event->data["meta"][] = array("name" => self::COMBO_CACHE_PREFIX . $slotId, "content" => hsc($value));
        }

    }

    function close(Doku_Event $event, $params)
    {
        CacheManager::close();
    }

    function imageHttpCacheBefore(Doku_Event $event, $params)
    {

        if (PluginUtility::getConfValue(self::CONF_STATIC_CACHE_ENABLED, 1)) {
            /**
             * If there is the buster key, the infinite cache is on
             */
            if (isset($_GET[CacheMedia::CACHE_BUSTER_KEY])) {

                /**
                 * To avoid buggy code, we check that the value is not empty
                 */
                $cacheKey = $_GET[CacheMedia::CACHE_BUSTER_KEY];
                if (!empty($cacheKey)) {

                    /**
                     * Only for Image
                     */
                    $mediaPath = DokuPath::createMediaPathFromId($event->data["media"]);
                    if ($mediaPath->isImage()) {

                        /**
                         * Only for public images
                         */
                        if (!$mediaPath->isPublic()) {
                            return;
                        }

                        /**
                         * We take over the complete {@link sendFile()} function and exit
                         *
                         * in {@link sendFile()}, DokuWiki set the `Cache-Control` and
                         * may exit early / send a 304 (not modified) with the function {@link http_conditionalRequest()}
                         * Meaning that the AFTER event is never reached
                         * that we can't send a cache control as below
                         * header("Cache-Control: public, max-age=$infiniteMaxAge, s-maxage=$infiniteMaxAge");
                         *
                         * We take the control over then
                         */

                        /**
                         * The mime
                         */
                        $mime = $mediaPath->getMime();
                        header("Content-Type: {$mime}");

                        /**
                         * The cache instructions
                         */
                        $infiniteMaxAge = self::INFINITE_MAX_AGE;
                        $expires = time() + $infiniteMaxAge;
                        header('Expires: ' . gmdate("D, d M Y H:i:s", $expires) . ' GMT');
                        header("Cache-Control: public, max-age=$infiniteMaxAge, immutable");
                        Http::removeHeaderIfPresent("Pragma");

                        /**
                         * The Etag cache validator
                         *
                         * Dokuwiki {@link http_conditionalRequest()} uses only the datetime of
                         * the file but we need to add the parameters also because they
                         * are generated image
                         *
                         * Last-Modified is not needed for the same reason
                         *
                         */
                        $etag = self::getEtagValue($mediaPath, $_REQUEST);
                        header("ETag: $etag");

                        /**
                         * Conditional Request ?
                         * We don't check on HTTP_IF_MODIFIED_SINCE because this is useless
                         */
                        if (isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
                            $ifNoneMatch = stripslashes($_SERVER['HTTP_IF_NONE_MATCH']);
                            if ($ifNoneMatch && $ifNoneMatch === $etag) {

                                header('HTTP/1.0 304 Not Modified');

                                /**
                                 * Clean the buffer to not produce any output
                                 */
                                @ob_end_clean();

                                /**
                                 * Exit
                                 */
                                PluginUtility::softExit("File not modified");
                            }
                        }

                        /**
                         * Send the file
                         */
                        $originalFile = $event->data["orig"]; // the original file
                        $physicalFile = $event->data["file"]; // the file modified
                        if (empty($physicalFile)) {
                            $physicalFile = $originalFile;
                        }

                        /**
                         * Download or display feature
                         * (Taken over from SendFile)
                         */
                        $download = $event->data["download"];
                        if ($download && $mime !== "image/svg+xml") {
                            header('Content-Disposition: attachment;' . rfc2231_encode(
                                    'filename', PhpString::basename($originalFile)) . ';'
                            );
                        } else {
                            header('Content-Disposition: inline;' . rfc2231_encode(
                                    'filename', PhpString::basename($originalFile)) . ';'
                            );
                        }

                        /**
                         * The vary header avoid caching
                         * Delete it
                         */
                        self::deleteVaryHeader();

                        /**
                         * Use x-sendfile header to pass the delivery to compatible web servers
                         * (Taken over from SendFile)
                         */
                        http_sendfile($physicalFile);

                        /**
                         * Send the file
                         */
                        $filePointer = @fopen($physicalFile, "rb");
                        if ($filePointer) {
                            http_rangeRequest($filePointer, filesize($physicalFile), $mime);
                        } else {
                            http_status(500);
                            print "Could not read $physicalFile - bad permissions?";
                        }

                        /**
                         * Stop the propagation
                         * Unfortunately, you can't stop the default ({@link sendFile()})
                         * because the event in fetch.php does not allow it
                         * We exit only if not test
                         */
                        $event->stopPropagation();
                        PluginUtility::softExit("File Send");

                    }
                }

            }
        }
    }

    /**
     * @param DokuPath $mediaPath
     * @param Array $properties - the query properties
     * @return string
     */
    public static function getEtagValue(DokuPath $mediaPath, array $properties): string
    {
        $etagString = $mediaPath->getModifiedTime()->format('r');
        ksort($properties);
        foreach ($properties as $key => $value) {
            /**
             * Media is already on the URL
             * tok is just added when w and h are on the url
             * Buster is the timestamp
             */
            if (in_array($key, ["media","tok",CacheMedia::CACHE_BUSTER_KEY])) {
                continue;
            }
            /**
             * If empty means not used
             */
            if(empty($value)){
                continue;
            }
            $etagString .= "$key=$value";
        }
        return '"' . md5($etagString) . '"';
    }


    /**
     * Delete the Vary header
     * @param Doku_Event $event
     * @param $params
     */
    public static function deleteVaryFromStaticGeneratedResources(Doku_Event $event, $params)
    {

        $script = $_SERVER["SCRIPT_NAME"];
        if (in_array($script, self::STATIC_SCRIPT_NAMES)) {
            // To be extra sure, they must have a tseed
            if (isset($_REQUEST["tseed"])) {
                self::deleteVaryHeader();
            }
        }

    }

    /**
     *
     * No Vary: Cookie
     * Introduced at
     * https://github.com/splitbrain/dokuwiki/issues/1594
     * But cache problem at:
     * https://github.com/splitbrain/dokuwiki/issues/2520
     *
     */
    public static function deleteVaryHeader(): void
    {
        if (PluginUtility::getConfValue(self::CONF_STATIC_CACHE_ENABLED, 1)) {
            Http::removeHeaderIfPresent("Vary");
        }
    }


}