From 55c322eb7955e6e5881ddcad7a2de61b2fc64faf Mon Sep 17 00:00:00 2001
From: David Valdez <david@agaric.com>
Date: Tue, 22 Jan 2019 12:05:38 -0600
Subject: [PATCH] Displays a link to switch the language.

Only if the content has been translated already.
---
 web/themes/custom/agarica/agarica.theme | 53 ++++++++++++++++++++++++-
 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/web/themes/custom/agarica/agarica.theme b/web/themes/custom/agarica/agarica.theme
index 210e044..f4980b3 100644
--- a/web/themes/custom/agarica/agarica.theme
+++ b/web/themes/custom/agarica/agarica.theme
@@ -1,6 +1,8 @@
 <?php
 
-use \Drupal\block\Entity\Block;
+use Drupal\block\Entity\Block;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Url;
 
 /**
  * Implements hook_preprocess_region__footer().
@@ -11,4 +13,53 @@ function agarica_preprocess_region__footer(&$variables) {
     ->getViewBuilder('block')
     ->view($block);
   $variables['language_switcher'] = $block_content;
+  $variables['language_switcher_link'] = agarica_languague_switch_link();
+}
+
+/**
+ * Provides a link to switch to another language.
+ */
+function agarica_languague_switch_link() {
+  $derivative_id = 'language_interface';
+  $route = \Drupal::getContainer()->get('path.matcher')->isFrontPage() ? '<front>' : '<current>';
+  $current_language = \Drupal::languageManager()->getCurrentLanguage($derivative_id)->getId();
+  $links = \Drupal::languageManager()->getLanguageSwitchLinks($derivative_id, Url::fromRoute($route))->links;
+  $links['en']['title'] = 'Browser this page on English.';
+  $links['es']['title'] = 'Consulta esta pagina en Español';
+  $lid = ($current_language == 'en') ? 'es' : 'en';
+  // Remove current language from the links
+  unset($links[$current_language]);
+
+  // Check if the current path  display an entity.
+  $entity = FALSE;
+  foreach (\Drupal::routeMatch()->getParameters() as $param) {
+    if ($param instanceof EntityInterface) {
+      $entity[] = $param;
+    }
+  }
+
+  // Remove links if the content hasnt' been translated yet.
+  if ($entity) {
+    $has_translation = (method_exists($entity[0], 'getTranslationStatus')) ? $entity[0]->getTranslationStatus($lid) : FALSE;
+    $this_translation = ($has_translation && method_exists($entity[0], 'getTranslation')) ? $entity[0]->getTranslation($lid) : FALSE;
+    $access_translation = ($this_translation && method_exists($this_translation, 'access') && $this_translation->access('view')) ? TRUE : FALSE;
+    if (!$this_translation || !$access_translation || $current_language == $lid) {
+      unset($links[$lid]);
+    }
+  }
+
+  $links_render_array = [];
+  // Transform the links to arrays that can be renderer.
+  foreach ($links as $language => $link) {
+    $links_render_array[] = [
+      '#type' => 'link',
+      '#url' => $link['url'],
+      '#title' => $link['title'],
+      '#options' => [
+        'language' => $link['language'],
+      ],
+    ];
+  }
+
+  return $links_render_array;
 }