<?php




function dynamiques_revue_save_post($post_id)
{
	$current_revue_ID = $post_id;
	$post_type = get_post_type($post_id);
	if ($post_type !== 'revues') return;

	// DE-LINK ARTICLES NOT USED IN THE ACF CHAPTER HANDLER IN REVUE POST ('articles' field)
	dynamiques_revue_empty_unmapped_articles($current_revue_ID);
	dynamiques_revue_link_mapped_articles($current_revue_ID);
}
add_action('acf/save_post', 'dynamiques_revue_save_post', 20);


function dynamiques_revue_empty_unmapped_articles($current_revue_ID)
{
	$articles = get_field('articles', $current_revue_ID);

	//  GET ALL ARTICLES RELATED TO THE REVUE AND CHECK IF THEY ARE HANDLED BY THE PARENT REVUE IN THE ARTICLE FIELD

	$articles_related_to_revue = new WP_Query(array(
		'post_type' => 'articles',
		'meta_query' => array(
			array(
				'key' => 'related_revue',
				'value' => $current_revue_ID,
				'compare' => '=',
			),
		),
	));

	$articles_related_to_revue_posts = $articles_related_to_revue->posts;


	$articles_related_to_revue_ids = array_map(function ($post) {
		return $post->ID;
	}, $articles_related_to_revue_posts);

	$articles_ids = array_map(function ($article) {
		return $article->ID;
	}, $articles);

	//  GET THE ARTICLES THAT ARE NOT HANDLED BY THE PARENT REVUE IN THE ARTICLE FIELD
	$unmapped_articles_ids = array_diff($articles_related_to_revue_ids, $articles_ids);


	//  EMPTY THE ARTICLE FIELD BECAUSE NOT USED BY THE PARENT REVUE

	foreach ($unmapped_articles_ids as $article_id) {
		update_field('related_revue', null, $article_id);
	}
}

function dynamiques_revue_link_mapped_articles($current_revue_ID)
{
	$articles = get_field('articles', $current_revue_ID);

	foreach ($articles as $article) {
		$article_id = $article->ID;
		$related_revue = get_field('related_revue', $article_id);
		update_field('related_revue', $current_revue_ID, $article_id);
	}
}