<?php

// Fix WordPress post meta import for our custom GUID
// The importer inserts a post, which creates a new GUID. Then it adds the
// post metas resulting in two GUID entries. Here we make sure to only use
// the previous one.
add_action('added_post_meta', function ($meta_id, $post_id, $meta_key, $_meta_value) {
    if ($meta_key !== '_podlove_guid') {
        return;
    }

    $metas = get_post_meta($post_id, '_podlove_guid');
    if (count($metas) > 1) {
        foreach ($metas as $meta) {
            if ($meta !== $_meta_value) {
                delete_post_meta($post_id, $meta_key, $meta);
            }
        }
    }
}, 10, 4);

// Ensure WordPress importer keeps the mapping id for old<->new post id.
// This is required for the Im/Export module. To avoid user errors, it is
// better to keep this behaviour in core.
add_filter('wp_import_post_meta', function ($postmetas, $post_id, $post) {
    $postmetas[] = [
        'key' => 'import_id',
        'value' => $post_id,
    ];

    return $postmetas;
}, 10, 3);