function bbp_edit_topic_handler( $action = '' ) {

	// Bail if action is not bbp-edit-topic
	if ( 'bbp-edit-topic' !== $action ) {
		return;
	}

	// Define local variable(s)
	$revisions_removed = false;
	$topic = $topic_id = $topic_author = $forum_id = 0;
	$topic_title = $topic_content = $topic_edit_reason = '';
	$anonymous_data = array();

	/** Topic *****************************************************************/

	// Topic id was not passed
	if ( empty( $_POST['bbp_topic_id'] ) ) {
		bbp_add_error( 'bbp_edit_topic_id', __( '<strong>ERROR</strong>: Topic ID not found.', 'bbpress' ) );
		return;

	// Topic id was passed
	} elseif ( is_numeric( $_POST['bbp_topic_id'] ) ) {
		$topic_id = (int) $_POST['bbp_topic_id'];
		$topic    = bbp_get_topic( $topic_id );
	}

	// Topic does not exist
	if ( empty( $topic ) ) {
		bbp_add_error( 'bbp_edit_topic_not_found', __( '<strong>ERROR</strong>: The topic you want to edit was not found.', 'bbpress' ) );
		return;

	// Topic exists
	} else {

		// Check users ability to create new topic
		if ( ! bbp_is_topic_anonymous( $topic_id ) ) {

			// User cannot edit this topic
			if ( ! current_user_can( 'edit_topic', $topic_id ) ) {
				bbp_add_error( 'bbp_edit_topic_permission', __( '<strong>ERROR</strong>: You do not have permission to edit that topic.', 'bbpress' ) );
			}

			// Set topic author
			$topic_author = bbp_get_topic_author_id( $topic_id );

		// It is an anonymous post
		} else {

			// Filter anonymous data
			$anonymous_data = bbp_filter_anonymous_post_data();
		}
	}

	// Nonce check
	if ( ! bbp_verify_nonce_request( 'bbp-edit-topic_' . $topic_id ) ) {
		bbp_add_error( 'bbp_edit_topic_nonce', __( '<strong>ERROR</strong>: Are you sure you wanted to do that?', 'bbpress' ) );
		return;
	}

	// Remove kses filters from title and content for capable users and if the nonce is verified
	if ( current_user_can( 'unfiltered_html' ) && ! empty( $_POST['_bbp_unfiltered_html_topic'] ) && ( wp_create_nonce( 'bbp-unfiltered-html-topic_' . $topic_id ) === $_POST['_bbp_unfiltered_html_topic'] ) ) {
		remove_filter( 'bbp_edit_topic_pre_title',   'wp_filter_kses'      );
		remove_filter( 'bbp_edit_topic_pre_content', 'bbp_encode_bad',  10 );
		remove_filter( 'bbp_edit_topic_pre_content', 'bbp_filter_kses', 30 );
	}

	/** Topic Forum ***********************************************************/

	// Forum id was not passed
	if ( empty( $_POST['bbp_forum_id'] ) ) {
		bbp_add_error( 'bbp_topic_forum_id', __( '<strong>ERROR</strong>: Forum ID is missing.', 'bbpress' ) );

	// Forum id was passed
	} elseif ( is_numeric( $_POST['bbp_forum_id'] ) ) {
		$forum_id = (int) $_POST['bbp_forum_id'];
	}

	// Current forum this topic is in
	$current_forum_id = bbp_get_topic_forum_id( $topic_id );

	// Forum exists
	if ( ! empty( $forum_id ) && ( $forum_id !== $current_forum_id ) ) {

		// Forum is a category
		if ( bbp_is_forum_category( $forum_id ) ) {
			bbp_add_error( 'bbp_edit_topic_forum_category', __( '<strong>ERROR</strong>: This forum is a category. No topics can be created in it.', 'bbpress' ) );

		// Forum is not a category
		} else {

			// Forum is closed and user cannot access
			if ( bbp_is_forum_closed( $forum_id ) && ! current_user_can( 'edit_forum', $forum_id ) ) {
				bbp_add_error( 'bbp_edit_topic_forum_closed', __( '<strong>ERROR</strong>: This forum has been closed to new topics.', 'bbpress' ) );
			}

			// Forum is private and user cannot access
			if ( bbp_is_forum_private( $forum_id ) && ! current_user_can( 'read_forum', $forum_id ) ) {
				bbp_add_error( 'bbp_edit_topic_forum_private', __( '<strong>ERROR</strong>: This forum is private and you do not have the capability to read or create new topics in it.', 'bbpress' ) );

			// Forum is hidden and user cannot access
			} elseif ( bbp_is_forum_hidden( $forum_id ) && ! current_user_can( 'read_forum', $forum_id ) ) {
				bbp_add_error( 'bbp_edit_topic_forum_hidden', __( '<strong>ERROR</strong>: This forum is hidden and you do not have the capability to read or create new topics in it.', 'bbpress' ) );
			}
		}
	}

	/** Topic Title ***********************************************************/

	if ( ! empty( $_POST['bbp_topic_title'] ) ) {
		$topic_title = sanitize_text_field( $_POST['bbp_topic_title'] );
	}

	// Filter and sanitize
	$topic_title = apply_filters( 'bbp_edit_topic_pre_title', $topic_title, $topic_id );

	// No topic title
	if ( empty( $topic_title ) ) {
		bbp_add_error( 'bbp_edit_topic_title', __( '<strong>ERROR</strong>: Your topic needs a title.', 'bbpress' ) );
	}

	// Title too long
	if ( bbp_is_title_too_long( $topic_title ) ) {
		bbp_add_error( 'bbp_topic_title', __( '<strong>ERROR</strong>: Your title is too long.', 'bbpress' ) );
	}

	/** Topic Content *********************************************************/

	if ( ! empty( $_POST['bbp_topic_content'] ) ) {
		$topic_content = $_POST['bbp_topic_content'];
	}

	// Filter and sanitize
	$topic_content = apply_filters( 'bbp_edit_topic_pre_content', $topic_content, $topic_id );

	// No topic content
	if ( empty( $topic_content ) ) {
		bbp_add_error( 'bbp_edit_topic_content', __( '<strong>ERROR</strong>: Your topic cannot be empty.', 'bbpress' ) );
	}

	/** Topic Bad Words *******************************************************/

	if ( ! bbp_check_for_moderation( $anonymous_data, $topic_author, $topic_title, $topic_content, true ) ) {
		bbp_add_error( 'bbp_topic_moderation', __( '<strong>ERROR</strong>: Your topic cannot be edited at this time.', 'bbpress' ) );
	}

	/** Topic Status **********************************************************/

	// Get available topic statuses
	$topic_statuses = bbp_get_topic_statuses( $topic_id );

	// Maybe put into moderation
	if ( ! bbp_check_for_moderation( $anonymous_data, $topic_author, $topic_title, $topic_content ) ) {

		// Set post status to pending if public or closed
		if ( bbp_is_topic_public( $topic->ID ) ) {
			$topic_status = bbp_get_pending_status_id();
		}

	// Check possible topic status ID's
	} elseif ( ! empty( $_POST['bbp_topic_status'] ) && in_array( $_POST['bbp_topic_status'], array_keys( $topic_statuses ), true ) ) {
		$topic_status = sanitize_key( $_POST['bbp_topic_status'] );

	// Use existing post_status
	} else {
		$topic_status = $topic->post_status;
	}

	/** Topic Tags ************************************************************/

	// Either replace terms
	if ( bbp_allow_topic_tags() && current_user_can( 'assign_topic_tags', $topic_id ) && ! empty( $_POST['bbp_topic_tags'] ) ) {

		// Escape tag input
		$terms = sanitize_text_field( $_POST['bbp_topic_tags'] );

		// Explode by comma
		if ( strstr( $terms, ',' ) ) {
			$terms = explode( ',', $terms );
		}

		// Add topic tag ID as main key
		$terms = array( bbp_get_topic_tag_tax_id() => $terms );

	// ...or remove them.
	} elseif ( isset( $_POST['bbp_topic_tags'] ) ) {
		$terms = array( bbp_get_topic_tag_tax_id() => array() );

	// Existing terms
	} else {
		$terms = array( bbp_get_topic_tag_tax_id() => explode( ',', bbp_get_topic_tag_names( $topic_id, ',' ) ) );
	}

	/** Additional Actions (Before Save) **************************************/

	do_action( 'bbp_edit_topic_pre_extras', $topic_id );

	// Bail if errors
	if ( bbp_has_errors() ) {
		return;
	}

	/** No Errors *************************************************************/

	// Add the content of the form to $topic_data as an array
	// Just in time manipulation of topic data before being edited
	$topic_data = apply_filters( 'bbp_edit_topic_pre_insert', array(
		'ID'           => $topic_id,
		'post_title'   => $topic_title,
		'post_content' => $topic_content,
		'post_status'  => $topic_status,
		'post_parent'  => $forum_id,
		'post_author'  => $topic_author,
		'post_type'    => bbp_get_topic_post_type(),
		'tax_input'    => $terms,
	) );

	// Toggle revisions to avoid duplicates
	if ( post_type_supports( bbp_get_topic_post_type(), 'revisions' ) ) {
		$revisions_removed = true;
		remove_post_type_support( bbp_get_topic_post_type(), 'revisions' );
	}

	// Insert topic
	$topic_id = wp_update_post( $topic_data );

	// Toggle revisions back on
	if ( true === $revisions_removed ) {
		$revisions_removed = false;
		add_post_type_support( bbp_get_topic_post_type(), 'revisions' );
	}

	/** No Errors *************************************************************/

	if ( ! empty( $topic_id ) && ! is_wp_error( $topic_id ) ) {

		// Update counts, etc...
		do_action( 'bbp_edit_topic', $topic_id, $forum_id, $anonymous_data, $topic_author , true /* Is edit */ );

		/** Revisions *********************************************************/

		// Update locks
		update_post_meta( $topic_id, '_edit_last', bbp_get_current_user_id() );
		delete_post_meta( $topic_id, '_edit_lock' );

		// Revision Reason
		if ( ! empty( $_POST['bbp_topic_edit_reason'] ) ) {
			$topic_edit_reason = sanitize_text_field( $_POST['bbp_topic_edit_reason'] );
		}

		// Update revision log
		if ( ! empty( $_POST['bbp_log_topic_edit'] ) && ( "1" === $_POST['bbp_log_topic_edit'] ) )  {
			$revision_id = wp_save_post_revision( $topic_id );
			if ( ! empty( $revision_id ) ) {
				bbp_update_topic_revision_log( array(
					'topic_id'    => $topic_id,
					'revision_id' => $revision_id,
					'author_id'   => bbp_get_current_user_id(),
					'reason'      => $topic_edit_reason
				) );
			}
		}

		/** Move Topic ********************************************************/

		// If the new forum id is not equal to the old forum id, run the
		// bbp_move_topic action and pass the topic's forum id as the
		// first arg and topic id as the second to update counts.
		if ( $forum_id !== $topic->post_parent ) {
			bbp_move_topic_handler( $topic_id, $topic->post_parent, $forum_id );
		}

		/** Additional Actions (After Save) ***********************************/

		do_action( 'bbp_edit_topic_post_extras', $topic_id );

		/** Redirect **********************************************************/

		// Redirect to
		$redirect_to = bbp_get_redirect_to();

		// View all?
		$view_all = bbp_get_view_all( 'edit_others_replies' );

		// Get the topic URL
		$topic_url = bbp_get_topic_permalink( $topic_id, $redirect_to );

		// Add view all?
		if ( ! empty( $view_all ) ) {
			$topic_url = bbp_add_view_all( $topic_url );
		}

		// Allow to be filtered
		$topic_url = apply_filters( 'bbp_edit_topic_redirect_to', $topic_url, $view_all, $redirect_to );

		/** Successful Edit ***************************************************/

		// Redirect back to new topic
		bbp_redirect( $topic_url );

	/** Errors ****************************************************************/

	} else {
		$append_error = ( is_wp_error( $topic_id ) && $topic_id->get_error_message() ) ? $topic_id->get_error_message() . ' ' : '';
		bbp_add_error( 'bbp_topic_error', __( '<strong>ERROR</strong>: The following problem(s) have been found with your topic:' . $append_error . 'Please try again.', 'bbpress' ) );
	}
}