// JavaScript Document
//*****************************************************************************
// Do not remove this notice.
//
// Copyright 2001 by Mike Hall.
// See http://www.brainjar.com for terms of use.
//*****************************************************************************
// To save you the suspense, this code is licensed under the terms of the GNU GPL v2 or later
// (at your option) as per http://www.brainjar.com/terms.asp
// --ccf

// Determine browser and version.

function Browser() {

  var ua, s, i;

  this.isIE    = false;
  this.isNS    = false;
  this.version = null;

  ua = navigator.userAgent;

  s = "MSIE";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isIE = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  s = "Netscape6/";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isNS = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  // Treat any other "Gecko" browser as NS 6.1.

  s = "Gecko";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isNS = true;
    this.version = 6.1;
    return;
  }
}

var browser = new Browser();

// Global object to hold drag information.
var dragObj = new Object();
dragObj.zIndex = 0;

// number of mouse moves to make a drag instead of a select
var MOUSE_MV_THRESHOLD = 4;
var mouseDnMv = 0;

function dragStart(event, id) {

  var el;
  var x, y;
  //document.getElementById('status').innerHTML = 'in dragStart';
  // ccf hackery to prevent select on drag
  mouseDnMv = 0;
  // end ccf hack

  // If an element id was given, find it. Otherwise use the element being
  // clicked on.

  if (id)
    dragObj.elNode = document.getElementById(id);
  else {
    if (browser.isIE)
      dragObj.elNode = window.event.srcElement;
    if (browser.isNS)
      dragObj.elNode = event.target;

    // If this is a text node, use its parent element.

//    if (dragObj.elNode.nodeType == 3)
//      dragObj.elNode = dragObj.elNode.parentNode;
    dragObj.elNode = findObjParent(dragObj.elNode);
  }

  // Get cursor position with respect to the page.

  if (browser.isIE) {
    x = window.event.clientX + document.documentElement.scrollLeft
      + document.body.scrollLeft;
    y = window.event.clientY + document.documentElement.scrollTop
      + document.body.scrollTop;
  }
  if (browser.isNS) {
    x = event.clientX + window.scrollX;
    y = event.clientY + window.scrollY;
  }

  // Save starting positions of cursor and element.

  dragObj.cursorStartX = x;
  dragObj.cursorStartY = y;
  dragObj.elStartLeft  = parseInt(dragObj.elNode.style.left, 10);
  dragObj.elStartTop   = parseInt(dragObj.elNode.style.top,  10);
  dragObj.elStartWidth = dragObj.elNode.width;
  dragObj.elStartHeight = dragObj.elNode.height;
  dragObj.aspR = dragObj.elNode.height / dragObj.elNode.width;
  dragObj.elStartCursor = dragObj.elNode.style.cursor;
  dragObj.elStartZ = dragObj.elNode.style.zIndex;

  if (isNaN(dragObj.elStartLeft)) dragObj.elStartLeft = 0;
  if (isNaN(dragObj.elStartTop))  dragObj.elStartTop  = 0;

  // a bit hackalicious: we only want to put the object on top if this is a genuine drag,
  // as opposed to just a click-to-select. So here we prep the maxZ value, and then in the
  // mousemove below, if we get over the threshold, we set the object's z value.
  maxZ++;
  // Update element's z-index.
  //dragObj.elNode.style.zIndex = ++dragObj.zIndex;

  dragObj.elNode.style.cursor = 'move';

  // Capture mousemove and mouseup events on the page.

  if (browser.isIE) {
    document.attachEvent("onmousemove", dragGo);
    document.attachEvent("onmouseup",   dragStop);
    window.event.cancelBubble = true;
    window.event.returnValue = false;
  }
  if (browser.isNS) {
    document.addEventListener("mousemove", dragGo,   true);
    document.addEventListener("mouseup",   dragStop, true);
    event.preventDefault();
  }
}

function dragGo(event) {

  var x, y;

  // Get cursor position with respect to the page.

  if (browser.isIE) {
    x = window.event.clientX + document.documentElement.scrollLeft
      + document.body.scrollLeft;
    y = window.event.clientY + document.documentElement.scrollTop
      + document.body.scrollTop;
  }
  if (browser.isNS) {
    x = event.clientX + window.scrollX;
    y = event.clientY + window.scrollY;
  }

  if(event.shiftKey && dragObj.elNode.src) {
    // aspect ratio is locked
    dragObj.elNode.width = Math.max(dragObj.elStartWidth + x - dragObj.cursorStartX, dragObj.elStartHeight + y - dragObj.cursorStartY);
    dragObj.elNode.height = dragObj.elNode.width * dragObj.aspR;
    // here, aspect ratio is free
    //dragObj.elNode.height = dragObj.elStartWidth + x - dragObj.cursorStartX;
    //dragObj.elNode.height = dragObj.elStartHeight + y - dragObj.cursorStartY;

    dragObj.elNode.style.cursor = 'se-resize';
    // if shift is down, this must be a genuine resize, and not a click-to-select
    mouseDnMv = MOUSE_MV_THRESHOLD;
  } else {
    // Move drag element by the same amount the cursor has moved.
    dragObj.elNode.style.left = (dragObj.elStartLeft + x - dragObj.cursorStartX) + "px";
    dragObj.elNode.style.top  = (dragObj.elStartTop  + y - dragObj.cursorStartY) + "px";
  }

  if (browser.isIE) {
    window.event.cancelBubble = true;
    window.event.returnValue = false;
  }
  if (browser.isNS)
    event.preventDefault();
    
  // if this val is above a certain threshold, we kill the click (we are dragging) -- ccf hack
  mouseDnMv++;

  // we only want to put the object on top if this is a genuine drag,
  // as opposed to just a click-to-select. So here, if we get over the threshold, we set the object's z value.
  // this will happen many times redundantly, but that's ok.
  if(mouseDnMv > MOUSE_MV_THRESHOLD) {
    dragObj.elNode.style.zIndex = maxZ;
  }
}

function dragStop(event) {

  // refresh the diplay of links
  // added by ccf for my application!
  refresh(event);

  // restore original cursor
  dragObj.elNode.style.cursor = dragObj.elStartCursor;

  // if this is NOT a real drag, but only a click-to-select, put the maxZ back to its old value
  if(mouseDnMv <= MOUSE_MV_THRESHOLD) {
    maxZ--;
  }

  // Stop capturing mousemove and mouseup events.

  if (browser.isIE) {
    document.detachEvent("onmousemove", dragGo);
    document.detachEvent("onmouseup",   dragStop);
  }
  if (browser.isNS) {
    document.removeEventListener("mousemove", dragGo,   true);
    document.removeEventListener("mouseup",   dragStop, true);
  }
}

// take an object; if it has a position setting (meaning it's a draggable object), return it, otherwise recurse on the parent.
// This is so that text elts with subnodes (ie, html tags embedded in them) can be draggable
function findObjParent(el)
{
  // if el is null, we have a problem.
  if(el.style && el.style.position)
    return el;
  else
    return findObjParent(el.parentNode);
}