package {
    import flash.display.*;
    import flash.events.*;
    import flash.geom.*
    
    // A viewer that displays a rectangular region of a TileMap using 
    // a specified TileSet. Supports mouse-dragging of the displayed map.
    public class @ax-actionscript-misc-DraggableMapRegion extends Sprite {
      private var map:actionscript_misc_TileMap;    // The map to display
      private var tiles:actionscript_misc_TileSet;  // The tiles used to render the map
      private var mapViewer:actionscript_misc_TileMapViewer;  // The displayed region of the map
  
      private var viewRect:Rectangle;       // The region to display
      private var lastViewRect:Rectangle;   // The last region displayed
      
      private var lastMouseX:Number;  // Previous horizontal mouse position
      private var lastMouseY:Number;  // Previous vertical mouse position
      private var dragging:Boolean;   // Flag indicating whether mouse 
                                      // movements should drag the map
      
      // Constructor
      public function @ax-actionscript-misc-DraggableMapRegion (map:actionscript_misc_TileMap, 
                                          tiles:actionscript_misc_TileSet,
                                          rect:Rectangle) {
        // Set the map, tiles, and region to display
        this.map = map;
        this.tiles = tiles;
        viewRect = rect;
        
        // Record the most recently displayed region
        lastViewRect = viewRect.clone();
  
        // Use a TileMapViewer object to handle map display 
        mapViewer = new actionscript_misc_TileMapViewer(map, tiles, viewRect);
        addChild(mapViewer);
        
        // Register to be notified when this @ax-actionscript-misc-DraggableMapRegion is added to
        // the stage ##[this needs fixing: ADDED is not ADDED_TO_STAGE]
        addEventListener(Event.ADDED, addedListener);
      }
  
      // When this @ax-actionscript-misc-DraggableMapRegion is added to the stage, 
      // register for mouse events
      private function addedListener (e:Event):void {
        stage.addEventListener(MouseEvent.MOUSE_MOVE, mouseMoveListener);
        addEventListener(MouseEvent.MOUSE_DOWN, mouseDownListener);
        stage.addEventListener(MouseEvent.MOUSE_UP, mouseUpListener);
      }
  
      // When the mouse clicks this @ax-actionscript-misc-DraggableMapRegion, start dragging the map
      private function mouseDownListener (e:MouseEvent):void {
        lastMouseX = e.stageX;
        lastMouseY = e.stageY;
        dragging = true;
      }
  
      // When the mouse is released, stop dragging the map
      private function mouseUpListener (e:MouseEvent):void {
        dragging = false;
      }
      
      // If dragging is activated, move the map in correspondence 
      // with mouse movements
      private function mouseMoveListener (e:MouseEvent):void {
        if (dragging) {
          // Determine the new region to display, based on mouse movement
          var moveX:int = e.stageX - lastMouseX;
          var moveY:int = e.stageY - lastMouseY;
          viewRect.x -= moveX;
          viewRect.y -= moveY;
  
          // Prevent the map from being dragged out of the displayed region
          var maxCropX:int = map.getNumCols()*tiles.getTileSize()
                           -viewRect.width;
          if (viewRect.x > maxCropX) {  // Don't drag too far right
            viewRect.x = maxCropX;
          } else if (viewRect.x < 0) {  // Don't drag too far left
            viewRect.x = 0;
          }
          var maxCropY:int = map.getNumRows()*tiles.getTileSize()
                           -viewRect.height;
          if (viewRect.y > maxCropY) {  // Don't drag too far up
            viewRect.y = maxCropY;
          } else if (viewRect.y < 0) {  // Don't drag too far down
            viewRect.y = 0;
          }
  
          // Record the current mouse position so that mouse distance
          // travelled can be calculated next time MouseEvent.MOUSE_MOVE
          // occurs
          lastMouseX = e.stageX;
          lastMouseY = e.stageY;
  
          // Redraw the map only if the display region has changed
          if (!viewRect.equals(lastViewRect)) {
            mapViewer.setViewRect(viewRect);
            e.updateAfterEvent();
            lastViewRect = viewRect.clone();
          }
        }
      }
    }
  }