polylang-smart-language-select-disabler.php

<?php
/**
 * Plugin Name: Smart Language Select Disabler for Polylang
 * Plugin URI: https://github.com/aucor/polylang-smart-language-select-disabler
 * Version: 1.1.1
 * Author: Aucor Oy
 * Author URI: https://github.com/aucor
 * Description: Disable content language select when there's translations in Polylang
 * License: GPLv2 or later
 * License URI: http://www.gnu.org/licenses/gpl-2.0.html
 *
 * @package polylang-smart-language-select-disabler
 */

/**
 *  Wrapper class for plugin functionality.
 */
class PolylangSmartLanguageSelectDisabler {

  /**
   * Constructor
   */
  public function __construct() {

    // Check that Polylang is active
    global $polylang;

    if ( isset( $polylang ) ) {
      add_action( 'current_screen', array( &$this, 'maybe_disable_language_select' ) );
      add_action( 'pll_default_lang_row_action', array( &$this, 'maybe_disable_default_language_select' ), 10, 2 );
    }
  } // end function __construct

  /**
   *  Maybe disable language select on edit posts and terms.
   *  Check switcher when there's translations. Switching language then will mess things up.
   *
   *  @param object $current_screen WP_Screen Object.
   */
  public function maybe_disable_language_select( $current_screen ) {

    $disable_translations = false;

    if ( 'post' === $current_screen->base ) {

      // $_GET['post'] has ID for all post types
      if ( isset( $_GET['post'] ) ) {
        $post_id = intval( $_GET['post'] );
        $disable_translations = PLL()->model->post->get_translations( $post_id );

      // $_GET['new_lang'] is used when creating a translation so there's always translations
      } elseif ( isset( $_GET['new_lang'] ) ) {
        $disable_translations = true;
      }
    } elseif ( 'term' === $current_screen->base ) {

      // $_GET['tag_ID'] has ID for all taxonomies
      if ( isset( $_GET['tag_ID'] ) ) {
        $term_id = intval( $_GET['tag_ID'] );
        $disable_translations = PLL()->model->term->get_translations( $term_id );

      // $_GET['new_lang'] is used when creating a translation so there's always translations
      } elseif ( isset( $_GET['new_lang'] ) ) {
        $disable_translations = true;
      }
    }

    // Posts bulk edit
    if ( 'edit' === $current_screen->base ) {
      $disable_translations = true;
    }

    // Terms bulk edit
    if ( 'edit-tags' === $current_screen->base ) {
      $disable_translations = true;
    }

    // Give filter to add custom logic for disabler
    $disable_translations = apply_filters( 'polylang-disable-language-select', $disable_translations, $current_screen );

    if ( $disable_translations ) {

      add_action( 'in_admin_header', function() {
        ?>

          <style>
            /* Bulk edit */
            .wp-admin .inline-edit-row select[name="inline_lang_choice"] {
              display: none !important;
            }

            /* Edit screens */
            .wp-admin #post_lang_choice,
            .wp-admin #term_lang_choice {
              display: none !important;
            }

            .wp-admin #select-post-language .pll-select-flag,
            .wp-admin #select-term-language, .pll-select-flag {
              margin-right: 6px;
            }

            .wp-admin #select-edit-term-language .description {
              display: none; /* Description doesn't apply */
            }
          </style>

          <script>

            function polylang_addon_disable_language_select( el, label ) {

              if( el == null ) {
                return false;
              }

              // get current language, if not already set
              if( label == null ) {
                var label = el.options[ el.selectedIndex ].innerHTML;
              }

              // create <p>
              var p = document.createElement( 'p' );
              p.style.display = 'inline-block';
              p.style.margin = '0';
              p.textContent = label;

              // insert <p>
              el.parentNode.insertBefore(p, el.nextSibling);

            }

            if( typeof addEventListener === 'function' ) {
              // Bulk edit
              document.addEventListener( 'DOMNodeInserted', function( e ) {
                var t = e.target;

                // WP inserts the quick edit from
                if ( '[object HTMLTableRowElement]' == Object.prototype.toString.call(t) && 'inline-edit' == t.getAttribute( 'id' ) ) {
                  // timeout so that inline lang choice gets real value
                  setTimeout(function() {
                    var lang_choice = document.getElementsByName('inline_lang_choice');
                    var lang_choice = lang_choice[0];
                    var label =  lang_choice.options[ lang_choice.selectedIndex ].innerHTML
                    polylang_addon_disable_language_select(lang_choice, label);
                  }, 5);
                }
              } );

              // Edit screens
              document.addEventListener('DOMContentLoaded', function() {

                // posts
                var post_lang_choice = document.getElementById('post_lang_choice');
                polylang_addon_disable_language_select(post_lang_choice);

                // terms
                var term_lang_choice = document.getElementById('term_lang_choice');
                polylang_addon_disable_language_select(term_lang_choice);

              });
            }
          </script>
        <?php
      });
    } // end if $disable_translations
  }

  /**
   *  Maybe disable Polylang default language change select
   *
   *  @param  string $s    html markup of the action.
   *  @param  object $item the item.
   *  @return string
   */
  public function maybe_disable_default_language_select( $s, $item ) {
    $disable = true;

    // Give get parameter to allow chaning the default language
    if ( isset( $_GET['iknowwhatimdoing'] ) ) {
      $disable = false;
    }

    // Give filter to add custom logic for disabler
    $disable = apply_filters( 'polylang-disable-default-language-select', $disable, $item );

    // Return empty string if disabled
    if ( $disable ) {
      return '';
    }

    // Return original string containing link to change
    return $s;
  }

} // end class PolylangSmartLanguageSelectDisabler

// Run plugin.
add_action( 'plugins_loaded', function() {
  global $polylang_smart_language_select_disabler;

  $polylang_smart_language_select_disabler = new PolylangSmartLanguageSelectDisabler();
} );