From e703e90c10b80dd569b1238676bb835e9746c941 Mon Sep 17 00:00:00 2001
From: Thomas Pike <tom.pike@xiven.com>
Date: Fri, 17 Jan 2025 11:50:15 +0100
Subject: [PATCH] Add support for WPML post locale (#1166)

* Add support for WPML post locale

* Address review check failures

* added missing changelog

---------

Co-authored-by: Matt Wiebe <wiebe@automattic.com>
Co-authored-by: Matthias Pfefferle <pfefferle@users.noreply.github.com>
---
 CHANGELOG.md               |  4 ++++
 integration/class-wpml.php | 40 ++++++++++++++++++++++++++++++++++++++
 integration/load.php       | 11 +++++++++++
 readme.txt                 |  1 +
 4 files changed, 56 insertions(+)
 create mode 100644 integration/class-wpml.php

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0741a3b45..6a9a7f9b9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+* Support for WPML post locale
+
 ### Removed
 
 * Built-in support for nodeinfo2. Use the [NodeInfo plugin](https://wordpress.org/plugins/nodeinfo/) instead.
diff --git a/integration/class-wpml.php b/integration/class-wpml.php
new file mode 100644
index 000000000..81c314ce8
--- /dev/null
+++ b/integration/class-wpml.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * WPML integration.
+ *
+ * @package Activitypub
+ */
+
+namespace Activitypub\Integration;
+
+/**
+ * Compatibility with the WPML Multilingual CMS plugin.
+ *
+ * @see https://wpml.org/
+ */
+class WPML {
+	/**
+	 * Initialize the class, registering WordPress hooks.
+	 */
+	public static function init() {
+		\add_filter( 'activitypub_post_locale', array( self::class, 'get_wpml_post_locale' ), 10, 2 );
+	}
+
+	/**
+	 * Fetch the post locale from the WPML post data.
+	 *
+	 * @param string $lang    The language code.
+	 * @param int    $post_id The post ID.
+	 *
+	 * @return string The modified language code.
+	 */
+	public static function get_wpml_post_locale( $lang, $post_id ) {
+		$language_details = apply_filters( 'wpml_post_language_details', null, $post_id );
+
+		if ( is_array( $language_details ) && isset( $language_details['language_code'] ) ) {
+			$lang = $language_details['language_code'];
+		}
+
+		return $lang;
+	}
+}
diff --git a/integration/load.php b/integration/load.php
index b5c9d27fc..ea8c48509 100644
--- a/integration/load.php
+++ b/integration/load.php
@@ -100,6 +100,17 @@ function ( $transformer, $data, $object_class ) {
 			3
 		);
 	}
+
+	/**
+	 * Adds WPML Multilingual CMS (plugin) support.
+	 *
+	 * This class handles the compatibility with the WPML plugin.
+	 *
+	 * @see https://wpml.org/
+	 */
+	if ( \defined( 'ICL_SITEPRESS_VERSION' ) ) {
+		WPML::init();
+	}
 }
 \add_action( 'plugins_loaded', __NAMESPACE__ . '\plugin_init' );
 
diff --git a/readme.txt b/readme.txt
index 49537699c..de59312d5 100644
--- a/readme.txt
+++ b/readme.txt
@@ -134,6 +134,7 @@ For reasons of data protection, it is not possible to see the followers of other
 
 = Unreleased =
 
+* Added: Support for WPML post locale
 * Removed: Built-in support for nodeinfo2. Use the [NodeInfo plugin](https://wordpress.org/plugins/nodeinfo/) instead.
 
 = 4.7.1 =