/**************************************************
 * dom-drag.js
 * 09.25.2001
 * www.youngpup.net
 * Script featured on Dynamic Drive (http://www.dynamicdrive.com) 12.08.2005
 **************************************************
 * 10.28.2001 - fixed minor bug where events
 * sometimes fired off the handle, not the root.
 **************************************************/

var Drag = {

  obj : null,

  init : function(o, oRoot, minX, maxX, minY, maxY, bSwapHorzRef, bSwapVertRef, fXMapper, fYMapper) {
    o.onmousedown = Drag.start;

    o.hmode     = bSwapHorzRef ? false : true;
    o.vmode     = bSwapVertRef ? false : true;

    o.root = oRoot && oRoot != null ? oRoot : o;

    if (o.hmode  && isNaN(parseInt(o.root.style.left, 10))) o.root.style.left   = "0px";
    if (o.vmode  && isNaN(parseInt(o.root.style.top, 10))) o.root.style.top    = "0px";
    if (!o.hmode && isNaN(parseInt(o.root.style.right, 10))) o.root.style.right  = "0px";
    if (!o.vmode && isNaN(parseInt(o.root.style.bottom, 10))) o.root.style.bottom = "0px";

    o.minX  = typeof minX != 'undefined' ? minX : null;
    o.minY  = typeof minY != 'undefined' ? minY : null;
    o.maxX  = typeof maxX != 'undefined' ? maxX : null;
    o.maxY  = typeof maxY != 'undefined' ? maxY : null;

    o.xMapper = fXMapper ? fXMapper : null;
    o.yMapper = fYMapper ? fYMapper : null;

    o.root.onDragStart  = new Function();
    o.root.onDragEnd  = new Function();
    o.root.onDrag   = new Function();
  },

  start : function(e) {
    showModalBackground(true);
    var o = Drag.obj = this;
    e = Drag.fixE(e);
    var y = parseInt(o.vmode ? o.root.style.top  : o.root.style.bottom, 10);
    var x = parseInt(o.hmode ? o.root.style.left : o.root.style.right, 10);
    o.root.onDragStart(x, y);

    // register that dialog is moved:
    top.dialogStackMoved[o.root.id] = true;

    o.lastMouseX  = e.clientX;
    o.lastMouseY  = e.clientY;

    if (o.hmode) {
      if (o.minX != null) o.minMouseX = e.clientX - x + o.minX;
      if (o.maxX != null) o.maxMouseX = o.minMouseX + o.maxX - o.minX;
    } else {
      if (o.minX != null) o.maxMouseX = -o.minX + e.clientX + x;
      if (o.maxX != null) o.minMouseX = -o.maxX + e.clientX + x;
    }

    if (o.vmode) {
      if (o.minY != null) o.minMouseY = e.clientY - y + o.minY;
      if (o.maxY != null) o.maxMouseY = o.minMouseY + o.maxY - o.minY;
    } else {
      if (o.minY != null) o.maxMouseY = -o.minY + e.clientY + y;
      if (o.maxY != null) o.minMouseY = -o.maxY + e.clientY + y;
    }

    document.onmousemove  = Drag.drag;
    document.onmouseup    = Drag.end;

    return false;
  },

  drag : function(e) {
    e = Drag.fixE(e);
    var o = Drag.obj;

    var ey  = e.clientY;
    var ex  = e.clientX;
    var y = parseInt(o.vmode ? o.root.style.top  : o.root.style.bottom, 10);
    var x = parseInt(o.hmode ? o.root.style.left : o.root.style.right, 10);
    var nx, ny;

    if (o.minX != null) ex = o.hmode ? Math.max(ex, o.minMouseX) : Math.min(ex, o.maxMouseX);
    if (o.maxX != null) ex = o.hmode ? Math.min(ex, o.maxMouseX) : Math.max(ex, o.minMouseX);
    if (o.minY != null) ey = o.vmode ? Math.max(ey, o.minMouseY) : Math.min(ey, o.maxMouseY);
    if (o.maxY != null) ey = o.vmode ? Math.min(ey, o.maxMouseY) : Math.max(ey, o.minMouseY);

    nx = x + ((ex - o.lastMouseX) * (o.hmode ? 1 : -1));
    ny = y + ((ey - o.lastMouseY) * (o.vmode ? 1 : -1));

    if (o.xMapper) { nx = o.xMapper(y); }
    else if (o.yMapper) { ny = o.yMapper(x); }

    Drag.obj.root.style[o.hmode ? "left" : "right"] = nx + "px";
    Drag.obj.root.style[o.vmode ? "top" : "bottom"] = ny + "px";
    Drag.obj.lastMouseX = ex;
    Drag.obj.lastMouseY = ey;

    //Drag.opac(7);

    Drag.obj.root.onDrag(nx, ny);
    return false;
  },

  end : function() {
    document.onmousemove = null;
    document.onmouseup   = null;
    Drag.obj.root.onDragEnd(parseInt(Drag.obj.root.style[Drag.obj.hmode ? "left" : "right"], 10), parseInt(Drag.obj.root.style[Drag.obj.vmode ? "top" : "bottom"], 10));
    //Drag.opac(10);
    Drag.obj = null;
    showModalBackground(false);
  },

  fixE : function(e) {
    if (typeof e == 'undefined') e = window.event;
    if (typeof e.layerX == 'undefined') e.layerX = e.offsetX;
    if (typeof e.layerY == 'undefined') e.layerY = e.offsetY;
    return e;
  },

  opac : function(value) {
    Drag.obj.root.style.opacity = value/10;
    Drag.obj.root.style.filter = 'alpha(opacity=' + value*10 + ')';
    Drag.obj.style.opacity = value/10;
    Drag.obj.style.filter = 'alpha(opacity=' + value*10 + ')';
  }
};