private onRegionChange()

in src/canvastools/ts/CanvasTools/Region/RegionsManager.ts [788:827]
40 lines of code
10 McCabe index (conditional complexity)

    private onRegionChange(region: Region, regionData: RegionData, state: ChangeEventType,
                           multiSelection: boolean = false) {
        // resize or drag begin
        if (state === ChangeEventType.MOVEBEGIN) {
            if (!multiSelection) {
                this.unselectRegions(region);
            }
            this.menu.hide();
            this.callbacks.onRegionSelected(region.ID, multiSelection);
            this.callbacks.onRegionMoveBegin(region.ID, regionData);
            this.justManipulated = false;
            // resizing or dragging
        } else if (state === ChangeEventType.MOVING) {
            this.callbacks.onRegionMove(region.ID, regionData);
            this.justManipulated = true;
            // resize or drag end
        } else if (state === ChangeEventType.MOVEEND) {
            if (this.justManipulated) {
                region.select();
                this.menu.showOnRegion(region);
                this.sortRegionsByArea();
            }
            this.callbacks.onRegionMoveEnd(region.ID, regionData);
        } else if (state === ChangeEventType.SELECTIONTOGGLE && !this.justManipulated) {
            // select
            if (!region.isSelected) {
                if (!multiSelection) {
                    this.unselectRegions(region);
                }
                region.select();
                this.menu.showOnRegion(region);
                this.callbacks.onRegionSelected(region.ID, multiSelection);
                // unselect
            } else {
                region.unselect();
                this.menu.hide();
                this.callbacks.onRegionSelected("", multiSelection);
            }
        }
    }