module Stone {
  
//  export declare type InitializationCallback = () => void;
  
//  export declare var StoneFrameworkModule : any;
  
  //const ASSETS_FOLDER : string = "assets/lib";
  //const WASM_FILENAME : string = "orthanc-framework";
  
  export class WasmViewport {

    private module_ : any;
    private canvasId_ : string;
    private htmlCanvas_ : HTMLCanvasElement;
    private context_ : CanvasRenderingContext2D;
    private imageData_ : any = null;
    private renderingBuffer_ : any = null;
    private touchZoom_ : any = false;
    private touchTranslation_ : any = false;

    private ViewportSetSize : Function;
    private ViewportRender : Function;
    private ViewportMouseDown : Function;
    private ViewportMouseMove : Function;
    private ViewportMouseUp : Function;
    private ViewportMouseEnter : Function;
    private ViewportMouseLeave : Function;
    private ViewportMouseWheel : Function;
    private ViewportKeyPressed : Function;

    public constructor(module: any, canvasId: string) {
      this.module_ = module;
      this.canvasId_ = canvasId;
      this.htmlCanvas_ = document.getElementById(this.canvasId_) as HTMLCanvasElement;
      this.context_ = this.htmlCanvas_.getContext('2d');

      this.ViewportSetSize = this.module_.cwrap('ViewportSetSize', null, [ 'number', 'number' ]);
      this.ViewportRender = this.module_.cwrap('ViewportRender', null, [ 'number', 'number', 'number', 'number' ]);
      this.ViewportMouseDown = this.module_.cwrap('ViewportMouseDown', null, [ 'number', 'number', 'number', 'number' ]);
      this.ViewportMouseMove = this.module_.cwrap('ViewportMouseMove', null, [ 'number', 'number' ]);
      this.ViewportMouseUp = this.module_.cwrap('ViewportMouseUp', null, [ ]);
      this.ViewportMouseEnter = this.module_.cwrap('ViewportMouseEnter', null, []);
      this.ViewportMouseLeave = this.module_.cwrap('ViewportMouseLeave', null, []);
      this.ViewportMouseWheel = this.module_.cwrap('ViewportMouseWheel', null, [ 'number', 'number', 'number', 'number' ]);
      this.ViewportKeyPressed = this.module_.cwrap('ViewportKeyPressed', null, [ 'string', 'number', 'number' ]);
    }

    public Redraw() {
      if (this.imageData_ === null ||
          this.renderingBuffer_ === null ||
          this.ViewportRender(this.imageData_.width,
                         this.imageData_.height,
                         this.renderingBuffer_) == 0) {
        console.log('The rendering has failed');
      } else {
        // Create an accessor to the rendering buffer (i.e. create a
        // "window" above the heap of the WASM module), then copy it to
        // the ImageData object
        this.imageData_.data.set(new Uint8ClampedArray(
          this.module_.buffer,
          this.renderingBuffer_,
          this.imageData_.width * this.imageData_.height * 4));
        
        this.context_.putImageData(this.imageData_, 0, 0);
      }
    }
  
    public Resize() {
      if (this.imageData_ != null &&
          (this.imageData_.width != window.innerWidth ||
           this.imageData_.height != window.innerHeight)) {
        this.imageData_ = null;
      }
      
      this.htmlCanvas_.width = window.innerWidth;
      this.htmlCanvas_.height = window.innerHeight;
  
      if (this.imageData_ === null) {
        this.imageData_ = this.context_.getImageData(0, 0, this.htmlCanvas_.width, this.htmlCanvas_.height);
        this.ViewportSetSize(this.htmlCanvas_.width, this.htmlCanvas_.height);
  
        if (this.renderingBuffer_ != null) {
          this.module_._free(this.renderingBuffer_);
        }
        
        this.renderingBuffer_ = this.module_._malloc(this.imageData_.width * this.imageData_.height * 4);
      }
      
      this.Redraw();
    }

    public Initialize() {

    // Force the rendering of the viewport for the first time
    this.Resize();
  
    // Register an event listener to call the Resize() function 
    // each time the window is resized.
    window.addEventListener('resize', this.Resize, false);
  
    var that = this;
  
    this.htmlCanvas_.addEventListener('contextmenu', function(event) {
      // Prevent right click on the canvas
      event.preventDefault();
    }, false);
    
    this.htmlCanvas_.addEventListener('mouseleave', function(event) {
      that.ViewportMouseLeave();
    });
    
    this.htmlCanvas_.addEventListener('mouseenter', function(event) {
      that.ViewportMouseEnter();
    });
  
    this.htmlCanvas_.addEventListener('mousedown', function(event) {
      var x = event.pageX - this.offsetLeft;
      var y = event.pageY - this.offsetTop;
      that.ViewportMouseDown(event.button, x, y, 0 /* TODO */);    
    });
  
    this.htmlCanvas_.addEventListener('mousemove', function(event) {
      var x = event.pageX - this.offsetLeft;
      var y = event.pageY - this.offsetTop;
      that.ViewportMouseMove(x, y);
    });
  
    this.htmlCanvas_.addEventListener('mouseup', function(event) {
      that.ViewportMouseUp();
    });
  
    window.addEventListener('keydown', function(event) {
      that.ViewportKeyPressed(event.key, event.shiftKey, event.ctrlKey, event.altKey);
    });
  
    this.htmlCanvas_.addEventListener('wheel', function(event) {
      var x = event.pageX - this.offsetLeft;
      var y = event.pageY - this.offsetTop;
      that.ViewportMouseWheel(event.deltaY, x, y, event.ctrlKey);
      event.preventDefault();
    });

    var that = this;
    this.htmlCanvas_.addEventListener('touchstart', function(event) {
      that.ResetTouch();
    });
  
    this.htmlCanvas_.addEventListener('touchend', function(event) {
      that.ResetTouch();
    });
    
    this.htmlCanvas_.addEventListener('touchmove', function(event) {
      if (that.touchTranslation_.length == 2) {
        var t = that.GetTouchTranslation(event);
        that.ViewportMouseMove(t[0], t[1]);
      }
      else if (that.touchZoom_.length == 3) {
        var z0 = that.touchZoom_;
        var z1 = that.GetTouchZoom(event);
        that.ViewportMouseMove(z0[0], z0[1] - z0[2] + z1[2]);
      }
      else {
        // Realize the gesture event
        if (event.targetTouches.length == 1) {
          // Exactly one finger inside the canvas => Setup a translation
          that.touchTranslation_ = that.GetTouchTranslation(event);
          that.ViewportMouseDown(1 /* middle button */,
                                 that.touchTranslation_[0],
                                 that.touchTranslation_[1], 0);
        } else if (event.targetTouches.length == 2) {
          // Exactly 2 fingers inside the canvas => Setup a pinch/zoom
          that.touchZoom_ = that.GetTouchZoom(event);
          var z0 = that.touchZoom_;
          that.ViewportMouseDown(2 /* right button */,
                                 z0[0],
                                 z0[1], 0);
        }        
      }
    });
  }  

  public ResetTouch() {
      if (this.touchTranslation_ ||
          this.touchZoom_) {
        this.ViewportMouseUp();
      }
  
      this.touchTranslation_ = false;
      this.touchZoom_ = false;
    }
  
  public GetTouchTranslation(event) {
      var touch = event.targetTouches[0];
      return [
        touch.pageX,
        touch.pageY
      ];
    }
    
  public GetTouchZoom(event) {
      var touch1 = event.targetTouches[0];
      var touch2 = event.targetTouches[1];
      var dx = (touch1.pageX - touch2.pageX);
      var dy = (touch1.pageY - touch2.pageY);
      var d = Math.sqrt(dx * dx + dy * dy);
      return [
        (touch1.pageX + touch2.pageX) / 2.0,
        (touch1.pageY + touch2.pageY) / 2.0,
        d
      ];
    }
    
  }
}