Copy Posts to Another Network Site

if ( ! is_multisite() ) {
    return;
}

add_filter( 'bulk_actions-edit-post', function ( $actions ) {
    foreach ( get_blogs_of_user( get_current_user_id() ) as $blog ) {
        if ( (int) $blog->userblog_id !== get_current_blog_id() ) {
            /* translators: %s: site name */
            $actions[ 'wpide_copy_to_' . (int) $blog->userblog_id ] = sprintf( __( 'Copy to: %s' ), $blog->blogname );
        }
    }

    return $actions;
} );

add_filter( 'handle_bulk_actions-edit-post', function ( $redirect, $action, $post_ids ) {
    if ( 0 !== strpos( $action, 'wpide_copy_to_' ) ) {
        return $redirect;
    }

    $target = absint( substr( $action, strlen( 'wpide_copy_to_' ) ) );

    if ( ! $target || ! is_user_member_of_blog( get_current_user_id(), $target ) ) {
        return $redirect;
    }

    $copies = array();
    foreach ( array_map( 'absint', $post_ids ) as $post_id ) {
        $post = get_post( $post_id );
        if ( $post && current_user_can( 'edit_post', $post_id ) ) {
            $copies[] = array(
                'post_title'   => $post->post_title,
                'post_content' => $post->post_content,
                'post_excerpt' => $post->post_excerpt,
                'source'       => get_permalink( $post ),
            );
        }
    }

    $done = 0;
    switch_to_blog( $target );
    if ( current_user_can( 'edit_posts' ) ) {
        foreach ( $copies as $copy ) {
            $new = wp_insert_post( array(
                'post_title'   => $copy['post_title'],
                'post_content' => $copy['post_content'],
                'post_excerpt' => $copy['post_excerpt'],
                'post_status'  => 'draft',
                'post_author'  => get_current_user_id(),
            ) );
            if ( $new && ! is_wp_error( $new ) ) {
                update_post_meta( $new, '_wpide_copied_from', esc_url_raw( $copy['source'] ) );
                $done++;
            }
        }
    }
    restore_current_blog();

    return add_query_arg( 'wpide_copied', $done, $redirect );
}, 10, 3 );

add_action( 'admin_notices', function () {
    if ( isset( $_GET['wpide_copied'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification
        $count = absint( $_GET['wpide_copied'] ); // phpcs:ignore WordPress.Security.NonceVerification
        /* translators: %d: number of posts */
        echo '<div class="notice notice-success is-dismissible"><p>' . esc_html( sprintf( _n( '%d post copied as a draft.', '%d posts copied as drafts.', $count ), $count ) ) . '</p></div>';
    }
} );