index.php

<?php
/*
Plugin Name: FacetWP - Polylang
Description: Polylang support for FacetWP
Version: 1.2.2
Author: FacetWP, LLC
Author URI: https://facetwp.com/
GitHub URI: facetwp/facetwp-polylang
*/

defined( 'ABSPATH' ) or exit;

class FWP_Polylang
{

    function __construct() {
        add_action( 'init' , array( $this, 'init' ) );
    }


    /**
     * Intialize
     */
    function init() {

        if ( function_exists( 'FWP' ) && function_exists( 'pll_register_string' ) ) {
            add_action( 'wp_footer', array( $this, 'wp_footer' ), 30 );
            add_action( 'admin_init', array( $this, 'register_strings' ) );
            add_action( 'facetwp_refresh', array( $this, 'set_langcode' ) );

            add_filter( 'facetwp_query_args', array( $this, 'facetwp_query_args' ), 10, 2 );
            add_filter( 'facetwp_indexer_query_args', array( $this, 'facetwp_indexer_query_args' ) );
            add_filter( 'facetwp_render_params', array( $this, 'support_preloader' ) );
            add_filter( 'facetwp_i18n', array( $this, 'facetwp_i18n' ) );
        }
        else {
            add_action( 'admin_notices', array( $this, 'admin_notice' ) );
        }
    }


    /**
     * Put the language into FWP_HTTP
     */
    function wp_footer() {
        if ( function_exists( 'pll_current_language' ) ) {
            $lang = pll_current_language();
            echo "<script>if ('undefined' != typeof FWP_HTTP) FWP_HTTP.lang = '$lang';</script>";
        }
    }


    /**
     * On ajax refreshes, set the langcode
     */
    function set_langcode() {
        if ( isset( FWP()->facet->http_params['lang'] ) ) {
            $_GET['lang'] = FWP()->facet->http_params['lang'];
        }
    }


    /**
     * Support FacetWP preloading (3.0.4+)
     */
    function support_preloader( $params ) {
        if ( isset( $params['is_preload'] ) && function_exists( 'pll_current_language' ) ) {
            $params['http_params']['lang'] = pll_current_language();
        }

        return $params;
    }


    /**
     * Query posts for the current language
     */
    function facetwp_query_args( $args, $class ) {
        if ( isset( $class->http_params['lang'] ) ) {
            $args['lang'] = $class->http_params['lang'];
        }

        return $args;
    }


    /**
     * Index all languages
     */
    function facetwp_indexer_query_args( $args ) {
        $args['lang'] = ''; // query posts in all languages
        return $args;
    }


    /**
     * Warn the user that Polylang is inactive
     */
    function admin_notice() {
?>
    <div class="error">
        <p><code>FacetWP - Polylang</code> requires the <a href="<?php echo admin_url(); ?>plugin-install.php?tab=search&s=polylang">Polylang</a> plugin. Please install and/or activate it.</p>
    </div>
<?php
    }


    /**
     * Register dynamic strings
     */
    function register_strings() {
        $facets = FWP()->helper->get_facets();
        $whitelist = array( 'label', 'label_any', 'placeholder' );

        if ( ! empty( $facets ) ) {
            foreach ( $facets as $facet ) {
                foreach ( $whitelist as $k ) {
                    if ( ! empty( $facet[ $k ] ) ) {
                        pll_register_string( 'FacetWP', $facet[ $k ] );
                    }
                }
            }
        }
    }


    /**
     * Handle string translations
     */
    function facetwp_i18n( $string ) {
        $lang = pll_current_language();
        $default = pll_default_language();

        if ( isset( FWP()->facet->http_params['lang'] ) ) {
            $lang = FWP()->facet->http_params['lang'];
        }

        if ( $lang != $default ) {
            return pll_translate_string( $string, $lang );
        }

        return $string;
    }
}


$fwp_polylang = new FWP_Polylang();