(function(window, document, undefined) {
  function ribbon(context) {
    this.init(context);
  }

  ribbon.prototype = {
    context : null,

    mouseX : null,
    mouseY : null,

    painters : null,

    interval : null,

    init : function(context) {
      this.context = context;
      this.context.lineWidth = 1;
      this.context.globalCompositeOperation = 'source-over';

      this.mouseX = SCREEN_WIDTH / 2;
      this.mouseY = SCREEN_HEIGHT / 2;

      this.painters = new Array();

      for ( var i = 0; i < 50; i++) {
        this.painters.push({
          dx : SCREEN_WIDTH / 2,
          dy : SCREEN_HEIGHT / 2,
          ax : 0,
          ay : 0,
          div : 0.1,
          ease : Math.random() * 0.2 + 0.6
        });
      }

      this.isDrawing = false;

      this.interval = setInterval(bargs(function(_this) {
        _this.update();
        return false;
      }, this), 1000 / 60);
    },

    destroy : function() {
      clearInterval(this.interval);
    },

    strokeStart : function(mouseX, mouseY) {
      this.mouseX = mouseX;
      this.mouseY = mouseY;

      this.context.strokeStyle = "rgba(" + COLOR[0] + ", " + COLOR[1] + ", " + COLOR[2] + ", 0.05 )";

      for ( var i = 0; i < this.painters.length; i++) {
        this.painters[i].dx = mouseX;
        this.painters[i].dy = mouseY;
      }

      this.shouldDraw = true;
    },

    stroke : function(mouseX, mouseY) {
      this.mouseX = mouseX;
      this.mouseY = mouseY;
    },

    strokeEnd : function() {

    },

    update : function() {
      var i;

      for (i = 0; i < this.painters.length; i++) {
        this.context.beginPath();
        this.context.moveTo(this.painters[i].dx, this.painters[i].dy);

        this.painters[i].dx -= this.painters[i].ax
                             = (this.painters[i].ax + (this.painters[i].dx - this.mouseX) * this.painters[i].div) * this.painters[i].ease;
        this.painters[i].dy -= this.painters[i].ay 
                             = (this.painters[i].ay + (this.painters[i].dy - this.mouseY) * this.painters[i].div) * this.painters[i].ease;
        this.context.lineTo(this.painters[i].dx, this.painters[i].dy);
        this.context.stroke();
      }
    }
  };

  function bargs(_fn) {
    var n, args = [];
    for (n = 1; n < arguments.length; n++)
      args.push(arguments[n]);

    return function() {
      return _fn.apply(this, args);
    };
  }

  var i,
    brush,
    BRUSHES = [ "ribbon" ],
    COLOR = [ 220, 220, 220 ],
    BACKGROUND_COLOR = [ 10, 10, 10 ],
    SCREEN_WIDTH = window.innerWidth,
    SCREEN_HEIGHT = window.innerHeight,
    container,
    foregroundColorSelector,
    backgroundColorSelector,
    menu,
    about,
    canvas,
    flattenCanvas,
    context,
    isForegroundColorSelectorVisible = false,
    isBackgroundColorSelectorVisible = false,
    isAboutVisible = false,
    isMenuMouseOver = false,
    shiftKeyIsDown = false,
    altKeyIsDown = false;

  window.harmony = function init() {
    var hash, palette;

    // quit if its firefox to avoid 100% cpu.
    if (/firefox|minefield/i.test(navigator.userAgent)) return;

    // /document.body.style.backgroundColor = 'rgb(' + BACKGROUND_COLOR[0] +
    // ', ' + BACKGROUND_COLOR[1] + ', ' + BACKGROUND_COLOR[2] + ')';

    container = document.createElement('div');
    document.body.appendChild(container);

    canvas = document.createElement("canvas");
    canvas.width = SCREEN_WIDTH;
    canvas.height = SCREEN_HEIGHT;
    canvas.style.cursor = 'crosshair';
    container.appendChild(canvas);

    if (!canvas.getContext) return;

    context = canvas.getContext("2d");

    flattenCanvas = document.createElement("canvas");
    flattenCanvas.width = SCREEN_WIDTH;
    flattenCanvas.height = SCREEN_HEIGHT;

    if (!brush) {
      brush = new ribbon(context);
    }

    window.addEventListener('mousemove', onWindowMouseMove, false);
    window.addEventListener('resize', onWindowResize, false);
    window.addEventListener('keydown', onDocumentKeyDown, false);
    window.addEventListener('keyup', onDocumentKeyUp, false);

    document.addEventListener('mouseout', onCanvasMouseUp, false);

    canvas.addEventListener('mousemove', onCanvasMouseMove, false);
    canvas.addEventListener('touchstart', onCanvasTouchStart, false);

    onWindowResize(null);
  };

  // WINDOW

  function onWindowMouseMove(event) {
    mouseX = event.clientX;
    mouseY = event.clientY;
  }

  function onWindowResize() {
    SCREEN_WIDTH = window.innerWidth;
    SCREEN_HEIGHT = window.innerHeight;

    /* make a copy */
    savecanvas = document.createElement("canvas");
    savecanvas.width = canvas.width;
    savecanvas.height = canvas.height;
    savecanvas.getContext("2d").drawImage(canvas, 0, 0);

    /* change the size */
    canvas.width = SCREEN_WIDTH;
    canvas.height = SCREEN_HEIGHT;

    /* draw the copy */
    context.drawImage(savecanvas, 0, 0);

    /* reset the brush (sad we lose the old random setup) */
    brush = new ribbon(context);
  }

  // DOCUMENT

  function onDocumentMouseDown(event) {
    if (!isMenuMouseOver) event.preventDefault();
  }

  function onDocumentKeyDown(event) {
    if (shiftKeyIsDown) return;

    switch (event.keyCode) {
      case 18: // Alt
        altKeyIsDown = true;
        break;
    }
  }

  function onDocumentKeyUp(event) {
    switch (event.keyCode) {
      case 16: // Shift
        shiftKeyIsDown = false;
        foregroundColorSelector.container.style.visibility = 'hidden';
        break;
      case 18: // Alt
        altKeyIsDown = false;
        break;
    }
  }

  // COLOR SELECTORS

  function setForegroundColor(x, y) {
    foregroundColorSelector.update(x, y);
    COLOR = foregroundColorSelector.getColor();
    menu.setForegroundColor(COLOR);
  }

  function onForegroundColorSelectorMouseDown(event) {
    window.addEventListener('mousemove', onForegroundColorSelectorMouseMove, false);
    window.addEventListener('mouseup', onForegroundColorSelectorMouseUp, false);

    setForegroundColor(event.clientX - foregroundColorSelector.container.offsetLeft,
                       event.clientY - foregroundColorSelector.container.offsetTop);
  }

  function onForegroundColorSelectorMouseMove(event) {
    setForegroundColor(event.clientX - foregroundColorSelector.container.offsetLeft,
                       event.clientY - foregroundColorSelector.container.offsetTop);
  }

  function onForegroundColorSelectorMouseUp(event) {
    window.removeEventListener('mousemove', onForegroundColorSelectorMouseMove, false);
    window.removeEventListener('mouseup', onForegroundColorSelectorMouseUp, false);

    setForegroundColor(event.clientX - foregroundColorSelector.container.offsetLeft,
                       event.clientY - foregroundColorSelector.container.offsetTop);
  }

  function onForegroundColorSelectorTouchStart(event) {
    if (event.touches.length == 1) {
      event.preventDefault();

      setForegroundColor(event.touches[0].pageX - foregroundColorSelector.container.offsetLeft,
                         event.touches[0].pageY - foregroundColorSelector.container.offsetTop);

      window.addEventListener('touchmove', onForegroundColorSelectorTouchMove, false);
      window.addEventListener('touchend', onForegroundColorSelectorTouchEnd, false);
    }
  }

  function onForegroundColorSelectorTouchMove(event) {
    if (event.touches.length == 1) {
      event.preventDefault();

      setForegroundColor(event.touches[0].pageX - foregroundColorSelector.container.offsetLeft,
                         event.touches[0].pageY - foregroundColorSelector.container.offsetTop);
    }
  }

  function onForegroundColorSelectorTouchEnd(event) {
    if (event.touches.length == 0) {
      event.preventDefault();

      window.removeEventListener('touchmove', onForegroundColorSelectorTouchMove, false);
      window.removeEventListener('touchend', onForegroundColorSelectorTouchEnd, false);
    }
  }

  //

  function setBackgroundColor(x, y) {
    backgroundColorSelector.update(x, y);
    BACKGROUND_COLOR = backgroundColorSelector.getColor();
    menu.setBackgroundColor(BACKGROUND_COLOR);

    document.body.style.backgroundColor = 'rgb(' + BACKGROUND_COLOR[0] + ', ' + BACKGROUND_COLOR[1] + ', '
        + BACKGROUND_COLOR[2] + ')';
  }

  function onBackgroundColorSelectorMouseDown(event) {
    window.addEventListener('mousemove', onBackgroundColorSelectorMouseMove, false);
    window.addEventListener('mouseup', onBackgroundColorSelectorMouseUp, false);
  }

  function onBackgroundColorSelectorMouseMove(event) {
    setBackgroundColor(event.clientX - backgroundColorSelector.container.offsetLeft,
                       event.clientY - backgroundColorSelector.container.offsetTop);
  }

  function onBackgroundColorSelectorMouseUp(event) {
    window.removeEventListener('mousemove', onBackgroundColorSelectorMouseMove, false);
    window.removeEventListener('mouseup', onBackgroundColorSelectorMouseUp, false);

    setBackgroundColor(event.clientX - backgroundColorSelector.container.offsetLeft,
                       event.clientY - backgroundColorSelector.container.offsetTop);
  }

  function onBackgroundColorSelectorTouchStart(event) {
    if (event.touches.length == 1) {
      event.preventDefault();

      setBackgroundColor(event.touches[0].pageX - backgroundColorSelector.container.offsetLeft,
                         event.touches[0].pageY - backgroundColorSelector.container.offsetTop);

      window.addEventListener('touchmove', onBackgroundColorSelectorTouchMove, false);
      window.addEventListener('touchend', onBackgroundColorSelectorTouchEnd, false);
    }
  }

  function onBackgroundColorSelectorTouchMove(event) {
    if (event.touches.length == 1) {
      event.preventDefault();

      setBackgroundColor(event.touches[0].pageX - backgroundColorSelector.container.offsetLeft,
                         event.touches[0].pageY - backgroundColorSelector.container.offsetTop);
    }
  }

  function onBackgroundColorSelectorTouchEnd(event) {
    if (event.touches.length == 0) {
      event.preventDefault();

      window.removeEventListener('touchmove', onBackgroundColorSelectorTouchMove, false);
      window.removeEventListener('touchend', onBackgroundColorSelectorTouchEnd, false);
    }
  }

  // MENU

  function onMenuForegroundColor() {
    cleanPopUps();

    foregroundColorSelector.show();
    foregroundColorSelector.container.style.left = ((SCREEN_WIDTH - foregroundColorSelector.container.offsetWidth) / 2) + 'px';
    foregroundColorSelector.container.style.top = ((SCREEN_HEIGHT - foregroundColorSelector.container.offsetHeight) / 2) + 'px';

    isForegroundColorSelectorVisible = true;
  }

  function onMenuBackgroundColor() {
    cleanPopUps();

    backgroundColorSelector.show();
    backgroundColorSelector.container.style.left = ((SCREEN_WIDTH - backgroundColorSelector.container.offsetWidth) / 2) + 'px';
    backgroundColorSelector.container.style.top = ((SCREEN_HEIGHT - backgroundColorSelector.container.offsetHeight) / 2) + 'px';

    isBackgroundColorSelectorVisible = true;
  }

  function onMenuSelectorChange() {
    if (BRUSHES[menu.selector.selectedIndex] == "") return;

    brush.destroy();
    brush = eval("new " + BRUSHES[menu.selector.selectedIndex] + "(context)");

    window.location.hash = BRUSHES[menu.selector.selectedIndex];
  }

  function onMenuMouseOver() {
    isMenuMouseOver = true;
  }

  function onMenuMouseOut() {
    isMenuMouseOver = false;
  }

  function onMenuSave() {
    var context = flattenCanvas.getContext("2d");

    context.fillStyle = 'rgb(' + BACKGROUND_COLOR[0] + ', ' + BACKGROUND_COLOR[1] + ', ' + BACKGROUND_COLOR[2] + ')';
    context.fillRect(0, 0, canvas.width, canvas.height);
    context.drawImage(canvas, 0, 0);

    window.open(flattenCanvas.toDataURL("image/png"), 'mywindow');
  }

  function onMenuClear() {
    context.clearRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);

    brush.destroy();
    brush = eval("new " + BRUSHES[menu.selector.selectedIndex] + "(context)");
  }

  function onMenuAbout() {
    cleanPopUps();

    isAboutVisible = true;
    about.show();
  }

  // CANVAS

  function onCanvasMouseMove(event) {
    if (!brush.isStroking) {
      brush.strokeStart(event.clientX, event.clientY);
      brush.isStroking = true;

      return;
    }

    var pts = onCanvasMouseMove.pts, results, x = event.clientX, y = event.clientY;

    onCanvasMouseMove.lastMove = +event.timeStamp;

    brush.stroke(x, y);
  }

  function onCanvasMouseUp() {
    brush.strokeEnd();

    window.removeEventListener('mousemove', onCanvasMouseMove, false);
    window.removeEventListener('mouseup', onCanvasMouseUp, false);
  }

  //

  function onCanvasTouchStart(event) {
    cleanPopUps();

    if (event.touches.length == 1) {
      event.preventDefault();

      brush.strokeStart(event.touches[0].pageX, event.touches[0].pageY);

      window.addEventListener('touchmove', onCanvasTouchMove, false);
      window.addEventListener('touchend', onCanvasTouchEnd, false);
    }
  }

  function onCanvasTouchMove(event) {
    if (event.touches.length == 1) {
      event.preventDefault();
      brush.stroke(event.touches[0].pageX, event.touches[0].pageY);
    }
  }

  function onCanvasTouchEnd(event) {
    if (event.touches.length == 0) {
      event.preventDefault();

      brush.strokeEnd();

      window.removeEventListener('touchmove', onCanvasTouchMove, false);
      window.removeEventListener('touchend', onCanvasTouchEnd, false);
    }
  }

  //

  function cleanPopUps() {
    if (isForegroundColorSelectorVisible) {
      foregroundColorSelector.hide();
      isForegroundColorSelectorVisible = false;
    }

    if (isBackgroundColorSelectorVisible) {
      backgroundColorSelector.hide();
      isBackgroundColorSelectorVisible = false;
    }

    if (isAboutVisible) {
      about.hide();
      isAboutVisible = false;
    }
  }

})(this, this.document);