<?php


use ComboStrap\Page;

/**
 * Class action_plugin_combo_metacanonical
 * Add all canonical HTML meta
 */
class action_plugin_combo_metacanonical
{


    public function register(Doku_Event_Handler $controller)
    {
        /**
         * https://www.dokuwiki.org/devel:event:tpl_metaheader_output
         */
        $controller->register_hook('TPL_METAHEADER_OUTPUT', 'BEFORE', $this, 'metaCanonicalProcessing', array());


    }

    /**
     * Dokuwiki has already a canonical methodology
     * https://www.dokuwiki.org/canonical
     *
     * @param $event
     */
    function metaCanonicalProcessing($event)
    {

        global $ID;
        if (empty($ID)) {
            // $_SERVER['SCRIPT_NAME']== "/lib/exe/mediamanager.php"
            // $ID is null
            return;
        }

        $page = Page::createPageFromId($ID);

        /**
         * No canonical for slot page
         */
        if ($page->isSlot()) {
            return;
        }

        /**
         * Where do we pick the canonical URL
         */
        /**
         * Canonical from meta
         *
         * FYI: The creation of the link was extracted from
         * {@link wl()} that call {@link idfilter()} that performs just a replacement
         * Calling the wl function will not work because
         * {@link wl()} use the constant DOKU_URL that is set before any test via getBaseURL(true)
         */
        $canonicalUrl = $page->getAbsoluteCanonicalUrl();

        /**
         * Replace the meta entry
         *
         * First search the key of the meta array
         */
        $canonicalKey = "";
        $canonicalRelArray = array("rel" => "canonical", "href" => $canonicalUrl);
        foreach ($event->data['link'] as $key => $link) {
            if ($link["rel"] == "canonical") {
                $canonicalKey = $key;
            }
        }
        if ($canonicalKey != "") {
            // Update
            $event->data['link'][$canonicalKey] = $canonicalRelArray;
        } else {
            // Add
            $event->data['link'][] = $canonicalRelArray;
        }

        /**
         * Add the Og canonical meta
         * https://developers.facebook.com/docs/sharing/webmasters/getting-started/versioned-link/
         */
        $canonicalOgKeyKey = "";
        $canonicalPropertyKey = "og:url";
        $canonicalOgArray = array("property" => $canonicalPropertyKey, "content" => $canonicalUrl);
        // Search if the canonical property is already present
        foreach ($event->data['meta'] as $key => $meta) {
            if (array_key_exists("property", $meta)) {
                /**
                 * We may have several properties
                 */
                if ($meta["property"] == $canonicalPropertyKey) {
                    $canonicalOgKeyKey = $key;
                }
            }
        }
        if ($canonicalOgKeyKey != "") {
            // Update
            $event->data['meta'][$canonicalOgKeyKey] = $canonicalOgArray;
        } else {
            // Add
            $event->data['meta'][] = $canonicalOgArray;
        }

    }

}