bp_document_forums_new_post_document_save( $post_id )

function bp_document_forums_new_post_document_save( $post_id ) {

	if ( ! empty( $_POST['bbp_document'] ) ) {

		// save activity id if it is saved in forums and enabled in platform settings.
		$main_activity_id = get_post_meta( $post_id, '_bbp_activity_id', true );

		// save document.
		$documents = json_decode( stripslashes( $_POST['bbp_document'] ), true );

		// fetch currently uploaded document ids.
		$existing_document                = array();
		$existing_document_ids            = get_post_meta( $post_id, 'bp_document_ids', true );
		$existing_document_attachment_ids = array();
		if ( ! empty( $existing_document_ids ) ) {
			$existing_document_ids = explode( ',', $existing_document_ids );

			foreach ( $existing_document_ids as $existing_document_id ) {
				$existing_document[ $existing_document_id ] = new BP_Document( $existing_document_id );

				if ( ! empty( $existing_document[ $existing_document_id ]->attachment_id ) ) {
					$existing_document_attachment_ids[] = $existing_document[ $existing_document_id ]->attachment_id;
				}
			}
		}

		$document_ids = array();
		foreach ( $documents as $document ) {

			$title                = ! empty( $document['name'] ) ? $document['name'] : '';
			$attachment_id        = ! empty( $document['id'] ) ? $document['id'] : 0;
			$attached_document_id = ! empty( $document['document_id'] ) ? $document['document_id'] : 0;
			$folder_id            = ! empty( $document['folder_id'] ) ? $document['folder_id'] : 0;
			$group_id             = ! empty( $document['group_id'] ) ? $document['group_id'] : 0;
			$forum_id             = ! empty( $document['forum_id'] ) ? $document['forum_id'] : 0;
			$topic_id             = ! empty( $document['topic_id'] ) ? $document['topic_id'] : 0;
			$reply_id             = ! empty( $document['reply_id'] ) ? $document['reply_id'] : 0;
			$menu_order           = ! empty( $document['menu_order'] ) ? $document['menu_order'] : 0;

			if ( ! empty( $existing_document_attachment_ids ) ) {
				$index = array_search( $attachment_id, $existing_document_attachment_ids );
				if ( ! empty( $attachment_id ) && $index !== false && ! empty( $existing_document[ $attached_document_id ] ) ) {

					$existing_document[ $attached_document_id ]->menu_order = $menu_order;
					$existing_document[ $attached_document_id ]->save();

					unset( $existing_document_ids[ $index ] );
					$document_ids[] = $attached_document_id;
					continue;
				}
			}

			if ( 0 === $reply_id && bbp_get_reply_post_type() === get_post_type( $post_id ) ) {
				$reply_id = $post_id;
				$topic_id = bbp_get_reply_topic_id( $reply_id );
				$forum_id = bbp_get_topic_forum_id( $topic_id );
			} elseif ( 0 === $topic_id && bbp_get_topic_post_type() === get_post_type( $post_id ) ) {
				$topic_id = $post_id;
				$forum_id = bbp_get_topic_forum_id( $topic_id );
			} elseif ( 0 === $forum_id && bbp_get_forum_post_type() === get_post_type( $post_id ) ) {
				$forum_id = $post_id;
			}

			$attachment_data = get_post( $document['id'] );
			$file            = get_attached_file( $document['id'] );
			$file_type       = wp_check_filetype( $file );
			$file_name       = basename( $file );

			$document_id = bp_document_add(
				array(
					'attachment_id' => $attachment_id,
					'title'         => $title,
					'folder_id'     => $folder_id,
					'group_id'      => $group_id,
					'privacy'       => 'forums',
					'error_type'    => 'wp_error',
					'menu_order'    => $menu_order,
				)
			);

			if ( ! is_wp_error( $document_id ) && ! empty( $document_id ) ) {
				$document_ids[] = $document_id;

				// save document meta.
				bp_document_update_meta( $document_id, 'forum_id', $forum_id );
				bp_document_update_meta( $document_id, 'topic_id', $topic_id );
				bp_document_update_meta( $document_id, 'reply_id', $reply_id );
				bp_document_update_meta( $document_id, 'file_name', $file_name );
				bp_document_update_meta( $document_id, 'extension', '.' . $file_type['ext'] );

				// save document is saved in attachment.
				update_post_meta( $attachment_id, 'bp_document_saved', true );
			}
		}

		$document_ids = implode( ',', $document_ids );

		// Save all attachment ids in forums post meta.
		update_post_meta( $post_id, 'bp_document_ids', $document_ids );

		// save document meta for activity.
		if ( ! empty( $main_activity_id ) && bp_is_active( 'activity' ) ) {
			bp_activity_update_meta( $main_activity_id, 'bp_document_ids', $document_ids );
		}

		// delete documents which were not saved or removed from form.
		if ( ! empty( $existing_document_ids ) ) {
			foreach ( $existing_document_ids as $document_id ) {
				bp_document_delete( array( 'id' => $document_id ) );
			}
		}
	}
}