<?php

/**
 * Class Ank_Simplified_GA
 * Frontend class for "Ank Simplified GA" Plugin
 * This class can run independently without admin class
 * @package Ank-Simplified-GA
 */
class Ank_Simplified_GA
{
    private static $instances = array();
    private $asga_options = array();

    private function __construct()
    {
        $this->set_db_options();
        $this->init();

    }

    /**
     * Function to instantiate our class and make it a singleton
     */
    public static function get_instance()
    {

        $cls = get_called_class();
        if (!isset(self::$instances[$cls])) {
            self::$instances[$cls] = new static;
        }
        return self::$instances[$cls];
    }

    protected function __clone()
    {
        //don't not allow clones
    }

    public function __wakeup()
    {
        throw new Exception("Cannot unserialize singleton");
    }

    /**
     * Store database options in a local array
     */
    private function set_db_options()
    {
        $this->asga_options = get_option(ASGA_OPTION_NAME);
    }

    /**
     * Init front end part
     */
    private function init()
    {
        //get action's priority
        $js_priority = absint($this->asga_options['js_priority']);

        //decide where to print code
        if ($this->asga_options['js_location'] == 1) {
            add_action('wp_head', array($this, 'decide_tracking_code'), $js_priority);
        } else {
            add_action('wp_footer', array($this, 'decide_tracking_code'), $js_priority);
        }

        //check for webmaster code
        if (!empty($this->asga_options['webmaster']['google_code'])) {
            add_action('wp_head', array($this, 'print_webmaster_code'), 9);
        }

        if ($this->need_to_load_event_tracking_js()) {
            //load event tracking js file
            add_action('wp_footer', array($this, 'add_event_tracking_js'));
        }

    }


    /**
     * Prepare and print javascript code to front end
     */
    function decide_tracking_code()
    {

        //get database options
        $options = $this->asga_options;

        //check if to proceed or not, return early with a message if not
        $tracking_status = $this->is_tracking_possible();
        if ($tracking_status !== true) {
            $this->load_view('ga_disabled.php', array('reason' => $tracking_status));
            return;
        }

        $ga_array = array();
        //get tracking id
        $ga_array['id'] = esc_js($options['ga_id']);
        //decide sub-domain
        $ga_array['domain'] = empty($options['ga_domain']) ? 'auto' : esc_js($options['ga_domain']);

        //these flags will be used in view
        $view_array = array(
            'gaq' => array()
        );

        //check for debug mode
        $view_array['debug_mode'] = $this->check_debug_mode($options);

        $view_array['js_load_later'] = (absint($options['js_load_later'])===1);


        if ($options['ua_enabled'] == 1) {
            //if universal is enabled
            $this->print_universal_code($view_array, $ga_array);

        } else {
            //classic ga is enabled
            $this->print_classic_code($view_array, $ga_array);

        }

    }

    /**
     * Prepare classic tracing code and print
     * @param $view_array array Array to be passed to view
     * @param $ga array
     */
    private function print_classic_code($view_array, $ga)
    {
        global $wp_query;
        $options = $this->asga_options;

        $view_array['ga_src'] = "('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'";
        if ($view_array['debug_mode'] == true) {
            //Did u notice additional /u in url ?
            //@source https://developers.google.com/analytics/resources/articles/gaTrackingTroubleshooting#gaDebug
            $view_array['ga_src'] = "('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/u/ga_debug.js'";
        }
        //@source https://support.google.com/analytics/answer/2444872
        if ($options['displayfeatures'] == 1) {
            $view_array['ga_src'] = "('https:' == document.location.protocol ? 'https://' : 'http://') + 'stats.g.doubleclick.net/dc.js'";
            if ($view_array['debug_mode'] == true) {
                $view_array['ga_src'] = "('https:' == document.location.protocol ? 'https://' : 'http://') + 'stats.g.doubleclick.net/dc_debug.js'";
            }
        }
        $view_array['gaq'][] = "'_setAccount', '" . $ga['id'] . "'";

        if ($ga['domain'] !== 'auto') {
            $view_array['gaq'][] = "'_setDomainName', '" . $ga['domain'] . "'";
        }

        if ($options['allow_linker'] == 1) {
            $view_array['gaq'][] = "'_setAllowLinker', true";
        }

        if ($options['allow_anchor'] == 1) {
            $view_array['gaq'][] = "'_setAllowAnchor', true";
        }

        if ($options['force_ssl'] == 1) {
            $view_array['gaq'][] = "'_gat._forceSSL'";
        }

        if ($options['anonymise_ip'] == 1) {
            $view_array['gaq'][] = "'_gat._anonymizeIp'";
        }

        $view_array['ela_plugin_url'] = false;
        if ($options['ga_ela'] == 1) {
            $view_array['ela_plugin_url'] = "var pluginUrl = '//www.google-analytics.com/plugins/ga/inpage_linkid.js';\n";
            $view_array['gaq'][] = "['_require', 'inpage_linkid', pluginUrl]";
        }

        if ($options['custom_trackers'] !== '') {
            $view_array['gaq'][] = array(
                'custom_trackers' => $options['custom_trackers']
            );
        }

        if (is_404() && $options['log_404'] == 1) {
            $view_array['gaq'][] = "'_trackEvent','404',document.location.href,document.referrer";
        } elseif ($wp_query->is_search && $options['log_search'] == 1) {
            $view_array['gaq'][] = "'_trackPageview','/?s=" . rawurlencode($wp_query->query_vars['s']) . "'";
        } else {
            $view_array['gaq'][] = "'_trackPageview'";
        }

        $this->load_view('classic_script.php', $view_array);

    }

    /**
     * Prepare universal tracking code and print
     * @param $view_array array Array to be passed to view
     * @param $ga array
     */
    private function print_universal_code($view_array, $ga)
    {
        global $wp_query;
        $options = $this->asga_options;

        if ($options['allow_linker'] == 1 && $options['allow_anchor'] == 0) {
            $view_array['gaq'][] = "'create', '" . $ga['id'] . "', '" . $ga['domain'] . "', {'allowLinker': true}";
        } else {
            if ($options['allow_anchor'] == 1 && $options['allow_linker'] == 0) {
                $view_array['gaq'][] = "'create', '" . $ga['id'] . "', '" . $ga['domain'] . "', {'allowAnchor': true}";
            } else {
                if ($options['allow_linker'] == 1 && $options['allow_anchor'] == 1) {
                    $view_array['gaq'][] = "'create', '" . $ga['id'] . "', '" . $ga['domain'] . "', {'allowLinker': true,'allowAnchor': true}";
                } else {
                    $view_array['gaq'][] = "'create', '" . $ga['id'] . "', '" . $ga['domain'] . "'";
                }
            }
        }

        if ($options['force_ssl'] == 1) {
            $view_array['gaq'][] = "'set', 'forceSSL', true";
        }

        if ($options['anonymise_ip'] == 1) {
            $view_array['gaq'][] = "'set', 'anonymizeIp', true";
        }
        /* Enable demographics and interests reports */
        if ($options['displayfeatures'] == 1) {
            $view_array['gaq'][] = "'require', 'displayfeatures'";
        }
        /* Enhanced Link Attribution */
        if ($options['ga_ela'] == 1) {
            $view_array['gaq'][] = "'require', 'linkid'";
        }
        if ($options['custom_trackers'] !== '') {
            $view_array['gaq'][] = array(
                'custom_trackers' => $options['custom_trackers']
            );
        }

        if (is_404() && $options['log_404'] == 1) {
            $view_array['gaq'][] = "'send','event','404',document.location.href,document.referrer";
        } elseif ($wp_query->is_search && $options['log_search'] == 1) {
            $view_array['gaq'][] = "'send','pageview','/?s=" . rawurlencode($wp_query->query_vars['s']) . "'";
        } else {
            $view_array['gaq'][] = "'send','pageview'";
        }

        $this->load_view('universal_script.php', $view_array);
    }

    /**
     * Print google webmaster meta tag to document header
     */
    function print_webmaster_code()
    {

        $this->load_view('google_webmaster.php', array('code' => $this->asga_options['webmaster']['google_code']));

    }

    /**
     * Enqueue event tracking javascript file
     */
    function add_event_tracking_js()
    {
        if ($this->is_tracking_possible() === true) {
            $is_min = (WP_DEBUG == 1) ? '' : '.min';
            //depends on jquery
            wp_enqueue_script('asga-event-tracking', plugins_url('/js/event-tracking' . $is_min . '.js', __FILE__), array('jquery'), ASGA_PLUGIN_VER, true);
            //wp inbuilt hack to print js options object just before this script
            wp_localize_script('asga-event-tracking', 'asga_opt', $this->get_js_options());
        }
    }


    /**
     * Load view and show it to front-end
     * @param $file string File name
     * @param $options array Array to be passed to view
     */
    private function load_view($file, $options)
    {
        $file_path = __DIR__ . '/views/' . $file;
        if (file_exists($file_path)) {
            require($file_path);
        } else {
            echo '<!-- Error: Unable to load ASGA template file - ' . esc_html(basename($file)) . ', (v' . ASGA_PLUGIN_VER . ')-->';
        }
    }


    /**
     * Check if to enable debugging mode
     * @param $options - Options array
     * @return bool
     */
    private function check_debug_mode($options)
    {
        //debug mode is only for logged-in admins/network admins
        if (current_user_can('manage_options') || is_super_admin()) {
            if ($options['debug_mode'] == 1) {
                return true;
            }
        }
        return false;
    }

    /**
     * Function determines whether to print tracking code or not
     * @return mixed Return true if possible and string if not possible
     */
    private function is_tracking_possible()
    {
        $options = $this->asga_options;

        if (is_preview()) {
            return 'GA Tracking is disabled in preview mode';
        } //if GA id is not set return early with a message
        else if (empty($options['ga_id'])) {
            return 'GA ID is not set';
        } //if a user is logged in
        else if (is_user_logged_in()) {

            if (is_multisite() && is_super_admin()) {
                //if a network admin is logged in
                if (isset($options['ignore_role_networkAdmin']) && ($options['ignore_role_networkAdmin'] == 1)) {
                    return 'GA Tracking is disabled for networkAdmin';
                }
            } else {
                //If a normal user is logged in
                $role = array_shift(wp_get_current_user()->roles);
                if (isset($options['ignore_role_' . $role]) && ($options['ignore_role_' . $role] == 1)) {
                    return 'GA Tracking is disabled for this role';
                }
            }
        }
        return true;

    }

    /**
     * Return array of options to be used in event tracking js
     * @return array
     */
    private function get_js_options()
    {
        $db_options = $this->asga_options;
        $js_options = array(
            'mail_links' => esc_js($db_options['track_mail_links']),
            'outgoing_links' => esc_js($db_options['track_outbound_links']),
            'download_links' => esc_js($db_options['track_download_links']),
            'download_ext' => esc_js($db_options['track_download_ext']),
            'outbound_link_type' => esc_js($db_options['track_outbound_link_type']),
        );
        return $js_options;
    }

    /**
     * Check if user wants any kind of event tracking
     * @return bool
     */
    private function need_to_load_event_tracking_js()
    {
        $db = $this->asga_options;
        return ($db['track_mail_links'] == 1 || $db['track_outbound_links'] == 1 || $db['track_download_links'] == 1);
    }
} //end class