Added Comment Metabox support

As Per: CMB2#238

*Changes in CMB2.php are optional for functionality.

includes/CMB2.php

@@ -528,6 +528,11 @@ public function object_id( $object_id = 0 ) {
 				$object_id = ! $object_id && isset( $GLOBALS['user_ID'] ) ? $GLOBALS['user_ID'] : $object_id;
 				break;
 
+			case 'comment':
+				$object_id = isset( $_REQUEST['c'] ) ? $_REQUEST['c'] : $object_id;
+				$object_id = ! $object_id && isset( $GLOBALS['comments']->comment_ID ) ? $GLOBALS['comments']->comment_ID : $object_id;
+				break;
+
 			default:
 				$object_id = isset( $GLOBALS['post']->ID ) ? $GLOBALS['post']->ID : $object_id;
 				$object_id = isset( $_REQUEST['post'] ) ? $_REQUEST['post'] : $object_id;

includes/CMB2_hookup.php

@@ -73,6 +73,19 @@ public function admin_hooks() {
 				$this->once( 'admin_head', array( $this, 'add_post_enctype' ) );
 			}
 
+		} elseif ( 'comment' == $type ) {
+			// Optionally - You could use the `add_meta_boxes_comment` hook.
+			add_action( 'add_meta_boxes_comment', array( $this, 'add_comment_metaboxes' ) );
+			add_action( 'add_attachment', array( $this, 'edit_comment' ) );
+			add_action( 'edit_attachment', array( $this, 'edit_comment' ) );
+			add_action( 'edit_comment', array( $this, 'edit_comment' ), 10, 2 );
+
+			$this->once( 'admin_enqueue_scripts', array( $this, 'do_scripts' ) );
+
+			if ( $has_upload && $pagenow === 'comment.php' ) {
+				$this->once( 'admin_head', array( $this, 'add_post_enctype' ) );
+			}
+
 		} elseif ( 'user' == $type ) {
 
 			$priority = $this->cmb->prop( 'priority' );
@@ -193,7 +206,7 @@ public static function register_scripts() {
 	 */
 	public function do_scripts( $hook ) {
 		// only enqueue our scripts/styles on the proper pages
-		if ( in_array( $hook, array( 'post.php', 'post-new.php', 'page-new.php', 'page.php' ), true ) ) {
+		if ( in_array( $hook, array( 'post.php', 'post-new.php', 'page-new.php', 'page.php', 'comment.php' ), true ) ) {
 			if ( $this->cmb->prop( 'cmb_styles' ) ) {
 				self::enqueue_cmb_css();
 			}
@@ -238,6 +251,25 @@ public function add_metaboxes() {
 		}
 	}
 
+	/**
+	 * Add metaboxes (to 'comment' object type)
+	 */
+	public function add_comment_metaboxes() {
+
+		if ( ! $this->show_on() ) {
+			return;
+		}
+
+		foreach ( $this->cmb->prop( 'object_types' ) as $page ) {
+
+			if ( $this->cmb->prop( 'closed' ) ) {
+				add_filter( "postbox_classes_{$page}_{$this->cmb->cmb_id}", array( $this, 'close_metabox_class' ) );
+			}
+
+			add_meta_box( $this->cmb->cmb_id, $this->cmb->prop( 'title' ), array( $this, 'comment_metabox' ), $page, $this->cmb->prop( 'context' ), $this->cmb->prop( 'priority' ) );
+		}
+	}
+
 	/**
 	 * Add 'closed' class to metabox
 	 * @since  2.0.0
@@ -257,6 +289,14 @@ public function post_metabox() {
 		$this->cmb->show_form( get_the_ID(), 'post' );
 	}
 
+	/**
+	 * Display metaboxes for a comment object
+	 * @since  1.0.0
+	 */
+	public function comment_metabox() {
+		$this->cmb->show_form( get_comment_ID(), 'comment' );
+	}
+
 	/**
 	 * Display metaboxes for new user page
 	 * @since  1.0.0
@@ -320,6 +360,36 @@ public function save_post( $post_id, $post = false ) {
 		$this->cmb->save_fields( $post_id, 'post', $_POST );
 	}
 
+	/**
+	 * Save data from metabox
+	 */
+	public function edit_comment( $comment_id, $comment = false ) {
+
+		$comment_type = $comment ? $comment->comment_type : get_comment_type( $comment_id );
+
+		$do_not_pass_go = (
+			// check nonce
+			! isset( $_POST[ $this->cmb->nonce() ] )
+			|| ! wp_verify_nonce( $_POST[ $this->cmb->nonce() ], $this->cmb->nonce() )
+			// check if autosave
+			|| defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE
+			// commented out - fails on custom comment types due to weak filtering in `get_comment_type()`
+			// || ( 'comment' !== $comment_type && ! current_user_can( 'moderate_comments', $comment_id ) )
+			// check user editing permissions
+			|| ! current_user_can( 'moderate_comments', $comment_id )
+			// get the metabox post_types & compare it to this post_type
+			|| ! in_array( $comment_type, $this->cmb->prop( 'object_types' ) )
+		);
+
+		if ( $do_not_pass_go ) {
+			// do not collect $200
+			return;
+		}
+
+		// take a trip to reading railroad – if you pass go collect $200
+		$this->cmb->save_fields( $comment_id, 'comment', $_POST );
+	}
+
 	/**
 	 * Save data from metabox
 	 */