<?php
/**
 * Theme Update Checker Library 1.2
 * http://w-shadow.com/.
 */
/*
json数据格式:
{
"version" : "12.3",
"details_url" : "https://u.xxoo.net/api/detial.txt",
"download_url" : "http://a.xxoo.net/Git-alpha.zip"
}
 */

if (!class_exists('ThemeUpdateChecker')) {
    class ThemeUpdateChecker
    {
        public $theme = ''; //待检查更新的主题名
        public $metadataUrl = ''; //元数据文件的路径
        public $enableAutomaticChecking = true; //是否启用自动更新
        protected $_optionName = ''; //更新信息的参数信息
        protected $_automaticCheckDone = false;
        protected static $_filterPrefix = 'tuc_request_update_';

        public function __construct($theme, $metadataUrl, $enableAutomaticChecking = true)
        {
            $this->metadataUrl = $metadataUrl;
            $this->enableAutomaticChecking = $enableAutomaticChecking;
            $this->theme = $theme;
            $this->optionName = 'external_theme_updates-'.$this->theme;
            $this->installHooks();
        }

        public function installHooks()
        {
            if ($this->enableAutomaticChecking) {
                add_filter('pre_set_site_transient_update_themes', [$this, 'onTransientUpdate']);
            }

            //Insert our update info into the update list maintained by WP.
            add_filter('site_transient_update_themes', [$this, 'injectUpdate']);

            //Delete our update info when WP deletes its own.
            //This usually happens when a theme is installed, removed or upgraded.
            add_action('delete_site_transient_update_themes', [$this, 'deleteStoredData']);
        }

        public function requestUpdate($queryArgs = [])
        {
            //Query args to append to the URL. Themes can add their own by using a filter callback (see addQueryArgFilter()).
            $queryArgs['installed_version'] = $this->getInstalledVersion();
            $queryArgs = apply_filters(self::$filterPrefix.'query_args-'.$this->theme, $queryArgs);

            //Various options for the wp_remote_get() call. Themes can filter these, too.
            $options = [
                'timeout' => 20, //seconds
            ];
            $options = apply_filters(self::$filterPrefix.'options-'.$this->theme, $options);

            $url = $this->metadataUrl;
            if (!empty($queryArgs)) {
                $url = add_query_arg($queryArgs, $url);
            }

            //Send the request.
            $result = wp_remote_get($url, $options);

            //Try to parse the response
            $themeUpdate = null;
            $code = wp_remote_retrieve_response_code($result);
            $body = wp_remote_retrieve_body($result);
            if ((200 == $code) && !empty($body)) {
                $themeUpdate = ThemeUpdate::fromJson($body);
                //The update should be newer than the currently installed version.
                if ((null != $themeUpdate) && version_compare($themeUpdate->version, $this->getInstalledVersion(), '<=')) {
                    $themeUpdate = null;
                }
            }

            return apply_filters(self::$filterPrefix.'result-'.$this->theme, $themeUpdate, $result);
        }

        public function getInstalledVersion()
        {
            if (function_exists('wp_get_theme')) {
                $theme = wp_get_theme($this->theme);

                return $theme->get('Version');
            }

            foreach ((array) get_themes() as $theme) {
                if ($theme['Stylesheet'] === $this->theme) {
                    return $theme['Version'];
                }
            }

            return '';
        }

        public function checkForUpdates()
        {
            $state = get_option($this->optionName);
            if (empty($state)) {
                $state = new StdClass();
                $state->lastCheck = 0;
                $state->checkedVersion = '';
                $state->update = null;
            }

            $state->lastCheck = time();
            $state->checkedVersion = $this->getInstalledVersion();
            update_option($this->optionName, $state); //Save before checking in case something goes wrong

            $state->update = $this->requestUpdate();
            update_option($this->optionName, $state);
        }

        public function onTransientUpdate($value)
        {
            if (!$this->automaticCheckDone) {
                $this->checkForUpdates();
                $this->automaticCheckDone = true;
            }

            return $value;
        }

        public function injectUpdate($updates)
        {
            $state = get_option($this->optionName);

            //Is there an update to insert?
            if (!empty($state) && isset($state->update) && !empty($state->update)) {
                $updates->response[$this->theme] = $state->update->toWpFormat();
            }

            return $updates;
        }

        public function deleteStoredData()
        {
            delete_option($this->optionName);
        }

        public function addQueryArgFilter($callback)
        {
            add_filter(self::$filterPrefix.'query_args-'.$this->theme, $callback);
        }

        public function addHttpRequestArgFilter($callback)
        {
            add_filter(self::$filterPrefix.'options-'.$this->theme, $callback);
        }

        public function addResultFilter($callback)
        {
            add_filter(self::$filterPrefix.'result-'.$this->theme, $callback, 10, 2);
        }
    }
}

if (!class_exists('ThemeUpdate')) {
    class ThemeUpdate
    {
        public $version; //Version number.
        public $details_url; //The URL where the user can learn more about this version.
        public $download_url; //The download URL for this version of the theme. Optional.

        public static function fromJson($json)
        {
            $apiResponse = json_decode($json);
            if (empty($apiResponse) || !is_object($apiResponse)) {
                return null;
            }

            //Very, very basic validation.
            $valid = isset($apiResponse->version) && !empty($apiResponse->version) && isset($apiResponse->details_url) && !empty($apiResponse->details_url);
            if (!$valid) {
                return null;
            }

            $update = new self();
            foreach ((array) get_object_vars($apiResponse) as $key => $value) {
                $update->{$key} = $value;
            }

            return $update;
        }

        public function toWpFormat()
        {
            $update = [
                'new_version' => $this->version,
                'url' => $this->details_url,
            ];

            if (!empty($this->download_url)) {
                $update['package'] = $this->download_url;
            }

            return $update;
        }
    }
}