Add a language filter for ACF options pages

.gitignore

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+# JetBrains IDE files
+.idea/

acf-compatibility.php

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+<?php
+
+use WPGraphQL\Registry\TypeRegistry;
+use WPGraphQL\Utils\Utils;
+
+/**
+ * Registers a new "wpmlLanguage" input field on ACF options pages queries, and
+ * uses translated options page content based on the language code supplied
+ * @throws Exception
+ */
+function wpgraphqlwpml_action_add_options_pages_language_filter(TypeRegistry $type_registry)
+{
+    foreach (acf_get_options_pages() as $options_page) {
+        // Check if the option page should be shown in GraphQL schema
+        if (!isset($options_page['show_in_graphql']) || false === (bool)$options_page['show_in_graphql']) {
+            continue;
+        }
+        $type_name = Utils::format_type_name($options_page['graphql_field_name'] ?? $options_page['menu_slug']);
+        // Register new options page field with the wpmlLanguage argument
+        $options_page['type'] = 'options_page';
+        $type_registry->register_field(
+            'RootQuery',
+            Utils::format_field_name($type_name),
+            [
+                'type' => $type_name,
+                'args' => [
+                    'wpmlLanguage' => [
+                        'type' => 'String',
+                        'description' => 'Filter by WPML language code',
+                    ],
+                ],
+                'description' => sprintf(__('%s options.', 'wp-graphql-acf'), $options_page['page_title']),
+                'resolve' => function ($unused, $args) use ($options_page) {
+                    // If the wpmlLanguage argument exists in the arguments
+                    if (isset($args['wpmlLanguage'])) {
+                        $lang = $args['wpmlLanguage'];
+                        global $sitepress;
+                        // If WPML is installed
+                        if ($sitepress) {
+                            // Switch the current locale WPML
+                            $sitepress->switch_lang($lang);
+                            // Override ACF language explicitly, otherwise the output language doesn't change
+                            acf_update_setting('current_language', $lang);
+                        }
+                    }
+                    return !empty($options_page) ? $options_page : null;
+                }
+            ]
+        );
+    }
+}
+
+function wpgraphqlwpml_init_acf()
+{
+    add_action(
+        'graphql_register_types',
+        'wpgraphqlwpml_action_add_options_pages_language_filter',
+        10,
+        1
+    );
+}