/**
 * Layer scrolling
 */

scrollObjs = {};
scrollObj.speed=100;
function scrollObj(wnId,lyrId,cntId){this.id=wnId;scrollObjs[this.id]=this;this.animString="scrollObjs."+this.id;this.load(lyrId,cntId);};scrollObj.loadLayer=function(wnId,id,cntId){if(scrollObjs[wnId])scrollObjs[wnId].load(id,cntId);};scrollObj.prototype.load=function(lyrId,cntId){if(!document.getElementById)return;var wndo,lyr;if(this.lyrId){lyr=document.getElementById(this.lyrId);lyr.style.visibility="hidden";}lyr=document.getElementById(lyrId);wndo=document.getElementById(this.id);lyr.style.top=this.y=0;lyr.style.left=this.x=0;this.maxY=(lyr.offsetHeight-wndo.offsetHeight>0)?lyr.offsetHeight-wndo.offsetHeight:0;this.wd=cntId?document.getElementById(cntId).offsetWidth:lyr.offsetWidth;this.maxX=(this.wd-wndo.offsetWidth>0)?this.wd-wndo.offsetWidth:0;this.lyrId=lyrId;lyr.style.visibility="visible";this.on_load();this.ready=true;};scrollObj.prototype.on_load=function(){};scrollObj.prototype.shiftTo=function(lyr,x,y){if(!lyr.style)return;lyr.style.left=(this.x=x)+"px";lyr.style.top=(this.y=y)+"px";};scrollObj.GeckoTableBugFix=function(){var ua=navigator.userAgent;if(ua.indexOf("Gecko")>-1&&ua.indexOf("Firefox")==-1&&ua.indexOf("Safari")==-1&&ua.indexOf("Konqueror")==-1){scrollObj.hold=[];for(var i=0;arguments[i];i++){if(scrollObjs[arguments[i]]){var wndo=document.getElementById(arguments[i]);var holderId=wndo.parentNode.id;var holder=document.getElementById(holderId);document.body.appendChild(holder.removeChild(wndo));wndo.style.zIndex=1000;var pos=getPageOffsets(holder);wndo.style.left=pos.x+"px";wndo.style.top=pos.y+"px";scrollObj.hold[i]=[arguments[i],holderId];}}window.addEventListener("resize",scrollObj.rePositionGecko,true);}};scrollObj.rePositionGecko=function(){if(scrollObj.hold){for(var i=0;scrollObj.hold[i];i++){var wndo=document.getElementById(scrollObj.hold[i][0]);var holder=document.getElementById(scrollObj.hold[i][1]);var pos=getPageOffsets(holder);wndo.style.left=pos.x+"px";wndo.style.top=pos.y+"px";}}};function getPageOffsets(el){var left=el.offsetLeft;var top=el.offsetTop;if(el.offsetParent&&el.offsetParent.clientLeft||el.offsetParent.clientTop){left+=el.offsetParent.clientLeft;top+=el.offsetParent.clientTop;}while(el=el.offsetParent){left+=el.offsetLeft;top+=el.offsetTop;}return{x:left,y:top};};

scrollObj.stopScroll = function(wnId) {
	if ( scrollObjs[wnId] ) scrollObjs[wnId].endScroll();
}

// increase speed onmousedown of scroll links
scrollObj.doubleSpeed = function(wnId) {
	if ( scrollObjs[wnId] ) scrollObjs[wnId].speed *= 2;
}

scrollObj.resetSpeed = function(wnId) {
	if ( scrollObjs[wnId] ) scrollObjs[wnId].speed /= 2;
}

// algorithms for time-based scrolling and scrolling onmouseover at any angle adapted from youngpup.net
scrollObj.initScroll = function(wnId, deg, sp) {
	if ( scrollObjs[wnId] ) {
		var cosine, sine;
		if (typeof deg == "string") {
			switch (deg) {
				case "up"    : deg = 90;  break;
				case "down"  : deg = 270; break;
				case "left"  : deg = 180; break;
				case "right" : deg = 0;   break;
				default:
					alert("Direction of scroll in mouseover scroll links should be 'up', 'down', 'left', 'right' or number: 0 to 360.");
			 }
		}
		deg = deg % 360;
		if (deg % 90 == 0) {
			cosine = (deg == 0)? -1: (deg == 180)? 1: 0;
			sine = (deg == 90)? 1: (deg == 270)? -1: 0;
		} else {
			var angle = deg * Math.PI/180;
			cosine = -Math.cos(angle); sine = Math.sin(angle);
		}
		scrollObjs[wnId].fx = cosine / ( Math.abs(cosine) + Math.abs(sine) );
		scrollObjs[wnId].fy = sine / ( Math.abs(cosine) + Math.abs(sine) );
		scrollObjs[wnId].endX = (deg == 90 || deg == 270)? scrollObjs[wnId].x:
			(deg < 90 || deg > 270)? -scrollObjs[wnId].maxX: 0;
		scrollObjs[wnId].endY = (deg == 0 || deg == 180)? scrollObjs[wnId].y:
			(deg < 180)? 0: -scrollObjs[wnId].maxY;
		scrollObjs[wnId].startScroll(sp);
	}
}

// speed (optional) to override default speed (set in scrollObj.speed)
scrollObj.prototype.startScroll = function(speed) {
	if (!this.ready) return; if (this.timerId) clearInterval(this.timerId);
	this.speed = speed || scrollObj.speed;
	this.lyr = document.getElementById(this.lyrId);
	this.lastTime = ( new Date() ).getTime();
	this.on_scroll_start();
	this.timerId = setInterval(this.animString + ".scroll()", 10);
}

scrollObj.prototype.scroll = function() {
	var now = ( new Date() ).getTime();
	var d = (now - this.lastTime)/1000 * this.speed;
	if (d > 0) {
		var x = this.x + this.fx * d; var y = this.y + this.fy * d;
		if (this.fx == 0 || this.fy == 0) { // for horizontal or vertical scrolling
			if ( ( this.fx == -1 && x > -this.maxX ) || ( this.fx == 1 && x < 0 ) ||
				( this.fy == -1 && y > -this.maxY ) || ( this.fy == 1 && y < 0 ) ) {
				this.lastTime = now;
				this.shiftTo(this.lyr, x, y);
				this.on_scroll(x, y);
			} else {
				clearInterval(this.timerId); this.timerId = 0;
				this.shiftTo(this.lyr, this.endX, this.endY);
				this.on_scroll_end(this.endX, this.endY);
			}
		} else { // for scrolling at an angle (stop when reach end on one axis)
			if ( ( this.fx < 0 && x >= -this.maxX && this.fy < 0 && y >= -this.maxY ) ||
				( this.fx > 0 && x <= 0 && this.fy > 0 && y <= 0 ) ||
				( this.fx < 0 && x >= -this.maxX && this.fy > 0 && y <= 0 ) ||
				( this.fx > 0 && x <= 0 && this.fy < 0 && y >= -this.maxY ) ) {
				this.lastTime = now;
				this.shiftTo(this.lyr, x, y);
				this.on_scroll(x, y);
			} else {
				clearInterval(this.timerId); this.timerId = 0;
				this.on_scroll_end(this.x, this.y);
			}
		}
	}
}

scrollObj.prototype.endScroll = function() {
	if (!this.ready) return;
	if (this.timerId) clearInterval(this.timerId);
	this.timerId = 0;  this.lyr = null;
}

scrollObj.prototype.on_scroll = function() {}
scrollObj.prototype.on_scroll_start = function() {}
scrollObj.prototype.on_scroll_end = function() {}

/* Glide scrolling */
scrollObj.slideDur = 500; // duration of glide

// intermediary functions needed to prevent errors before page loaded
scrollObj.scrollBy = function(wnId, x, y, dur) {
	if ( scrollObjs[wnId] ) scrollObjs[wnId].glideBy(x, y, dur);
}

scrollObj.scrollTo = function(wnId, x, y, dur) {
	if ( scrollObjs[wnId] ) scrollObjs[wnId].glideTo(x, y, dur);
}

// Resources for time-based slide algorithm:
//  DHTML chaser tutorial at DHTML Lab - www.webreference.com/dhtml	
//  and cbe_slide.js from	www.cross-browser.com by Mike Foster
scrollObj.prototype.glideBy = function(dx, dy, dur) {
	if ( !document.getElementById || this.sliding ) return;
	this.slideDur = dur || scrollObj.slideDur;
	this.destX = this.destY = this.distX = this.distY = 0;
	this.lyr = document.getElementById(this.lyrId);
	this.startX = this.x; this.startY = this.y;
	if (dy < 0) this.distY = (this.startY + dy >= -this.maxY)? dy: -(this.startY  + this.maxY);
	else if (dy > 0) this.distY = (this.startY + dy <= 0)? dy: -this.startY;
	if (dx < 0) this.distX = (this.startX + dx >= -this.maxX)? dx: -(this.startX + this.maxX);
	else if (dx > 0) this.distX = (this.startX + dx <= 0)? dx: -this.startX;
	this.destX = this.startX + this.distX; this.destY = this.startY + this.distY;
	this.slideTo(this.destX, this.destY);
}

scrollObj.prototype.glideTo = function(destX, destY, dur) {
	if ( !document.getElementById || this.sliding) return;
	this.slideDur = dur || scrollObj.slideDur;
	this.lyr = document.getElementById(this.lyrId);
	this.startX = this.x; this.startY = this.y;
	this.destX = -Math.max( Math.min(destX, this.maxX), 0);
	this.destY = -Math.max( Math.min(destY, this.maxY), 0);
	this.distY = this.destY - this.startY;
	this.distX =  this.destX - this.startX;
	this.slideTo(this.destX, this.destY);
}

scrollObj.prototype.slideTo = function(destX, destY) {
	this.per = Math.PI/(2 * this.slideDur); this.sliding = true;
	this.slideStart = (new Date()).getTime();
	this.aniTimer = setInterval(this.animString + ".doSlide()",10);
	this.on_slide_start(this.startX, this.startY);
}

scrollObj.prototype.doSlide = function() {
	var elapsed = (new Date()).getTime() - this.slideStart;
	if (elapsed < this.slideDur) {
		var x = this.startX + this.distX * Math.sin(this.per*elapsed);
		var y = this.startY + this.distY * Math.sin(this.per*elapsed);
		this.shiftTo(this.lyr, x, y); this.on_slide(x, y);
	} else {	// if time's up
		clearInterval(this.aniTimer); this.sliding = false;
		this.shiftTo(this.lyr, this.destX, this.destY);
		this.lyr = null; this.on_slide_end(this.destX, this.destY);
	}
}

scrollObj.prototype.on_slide_start = function() {}
scrollObj.prototype.on_slide = function() {}
scrollObj.prototype.on_slide_end = function() {}


// model: Aaron Boodman's dom drag at www.youngpup.net
var dw_slidebar = {
	obj: null,
	slideDur: 500,  // duration of glide onclick of track
	init: function (bar, track, axis, x, y) {
		x = x || 0; y = y || 0;
		bar.style.left = x + "px"; bar.style.top = y + "px";
		bar.axis = axis; track.bar = bar;
		if (axis == "h") {
			bar.trkWd = track.offsetWidth; // hold for setBarSize
			bar.maxX = bar.trkWd - bar.offsetWidth - x;
			bar.minX = x; bar.maxY = y; bar.minY = y;
		} else {
			bar.trkHt = track.offsetHeight;
			bar.maxY = bar.trkHt - bar.offsetHeight - y;
			bar.maxX = x; bar.minX = x; bar.minY = y;
		}
		bar.on_drag_start =  bar.on_drag =   bar.on_drag_end =
		bar.on_slide_start = bar.on_slide =  bar.on_slide_end = function() {}
		bar.onmousedown = this.startDrag; track.onmousedown = this.startSlide;
	},

	startSlide: function(e) { // called onmousedown of track
		if ( dw_slidebar.aniTimer ) clearInterval(dw_slidebar.aniTimer);
		e = e? e: window.event;
		var bar = dw_slidebar.obj = this.bar; // i.e., track's bar
		e.offX = (typeof e.layerX != "undefined")? e.layerX: e.offsetX;
		e.offY = (typeof e.layerY != "undefined")? e.layerY: e.offsetY;
		bar.startX = parseInt(bar.style.left); bar.startY = parseInt(bar.style.top);
		if (bar.axis == "v") {
			bar.destX = bar.startX;
			bar.destY = (e.offY < bar.startY)? e.offY: e.offY - bar.offsetHeight;
			bar.destY = Math.min( Math.max(bar.destY, bar.minY), bar.maxY );
		} else {
			bar.destX = (e.offX < bar.startX)? e.offX: e.offX - bar.offsetWidth;
			bar.destX = Math.min( Math.max(bar.destX, bar.minX), bar.maxX );
			bar.destY = bar.startY;
		}
		bar.distX = bar.destX - bar.startX; bar.distY = bar.destY - bar.startY;
		dw_slidebar.per = Math.PI/(2 * dw_slidebar.slideDur);
		dw_slidebar.slideStart = (new Date()).getTime();
		bar.on_slide_start(bar.startX, bar.startY);
		dw_slidebar.aniTimer = setInterval("dw_slidebar.doSlide()",10);
	},

	doSlide: function() {
		if ( !dw_slidebar.obj ) { clearInterval(dw_slidebar.aniTimer); return; }
		var bar = dw_slidebar.obj;
		var elapsed = (new Date()).getTime() - this.slideStart;
		if (elapsed < this.slideDur) {
			var x = bar.startX + bar.distX * Math.sin(this.per*elapsed);
			var y = bar.startY + bar.distY * Math.sin(this.per*elapsed);
			bar.style.left = x + "px"; bar.style.top = y + "px";
			bar.on_slide(x, y);
		} else { // if time's up
			clearInterval(this.aniTimer);
			bar.style.left = bar.destX + "px"; bar.style.top = bar.destY + "px";
			bar.on_slide_end(bar.destX, bar.destY);
			this.obj = null;
		}
	},

	startDrag: function (e) { // called onmousedown of bar
		e = dw_event.DOMit(e);
		if ( dw_slidebar.aniTimer ) clearInterval(dw_slidebar.aniTimer);
		var bar = dw_slidebar.obj = this;
		bar.downX = e.clientX; bar.downY = e.clientY;
		bar.startX = parseInt(bar.style.left);
		bar.startY = parseInt(bar.style.top);
		bar.on_drag_start(bar.startX, bar.startY);
		dw_event.add( document, "mousemove", dw_slidebar.doDrag, true );
		dw_event.add( document, "mouseup",   dw_slidebar.endDrag,  true );
		e.stopPropagation();
	},

	doDrag: function (e) {
		e = e? e: window.event;
		if (!dw_slidebar.obj) return;
		var bar = dw_slidebar.obj;
		var nx = bar.startX + e.clientX - bar.downX;
		var ny = bar.startY + e.clientY - bar.downY;
		nx = Math.min( Math.max( bar.minX, nx ), bar.maxX);
		ny = Math.min( Math.max( bar.minY, ny ), bar.maxY);
		bar.style.left = nx + "px"; bar.style.top  = ny + "px";
		bar.on_drag(nx,ny);
		return false;
	},

	endDrag: function () {
		dw_event.remove( document, "mousemove", dw_slidebar.doDrag, true );
		dw_event.remove( document, "mouseup",   dw_slidebar.endDrag,  true );
		if ( !dw_slidebar.obj ) return; // avoid errors in ie if inappropriate selections
		dw_slidebar.obj.on_drag_end( parseInt(dw_slidebar.obj.style.left), parseInt(dw_slidebar.obj.style.top) );
		dw_slidebar.obj = null;
	}

}


// Size dragBar according to layer size?
scrollObj.prototype.bSizeDragBar = true;

scrollObj.prototype.setUpScrollbar = function(id, trkId, axis, offx, offy) {
	if (!document.getElementById) return;
	var bar = document.getElementById(id);
	var trk = document.getElementById(trkId);
	dw_slidebar.init(bar, trk, axis, offx, offy);
	// connect dw_slidebar with scrollObj
	bar.wn = scrollObjs[this.id]; // scroll area object this bar connected to
	if (axis == "v") this.vBarId = id; else this.hBarId = id;
	// also called on_load (i.e., when layer loaded), but in case h and v scrollbars, need to call here too
	if (this.bSizeDragBar) this.setBarSize();
	bar.on_drag_start = bar.on_slide_start = scrollObj.getWndoLyrRef;
	bar.on_drag_end =   bar.on_slide_end =   scrollObj.tossWndoLyrRef;
	bar.on_drag =       bar.on_slide =       scrollObj.UpdateWndoLyrPos;
}

// for these 3 functions (assigned to bar.on_drag/slide...) "this" refers to bar
// get/discard ref to layer visible in scroll area
scrollObj.getWndoLyrRef = function()  { this.wnLyr = document.getElementById(this.wn.lyrId); }
scrollObj.tossWndoLyrRef = function() { this.wnLyr = null; }
// keep position of scrolling layer in synch with slide/drag of bar
scrollObj.UpdateWndoLyrPos = function(x, y) {
	var nx, ny;
	if (this.axis == "v") {
		nx = this.wn.x; // floating point values for loaded layer's position held in shiftTo method
		ny = -(y - this.minY) * ( this.wn.maxY / (this.maxY - this.minY) ) || 0;
	} else {
		ny = this.wn.y;
		nx = -(x - this.minX) * ( this.wn.maxX / (this.maxX - this.minX) ) || 0;
	}
	this.wn.shiftTo(this.wnLyr, nx, ny);
}

// Keep position of dragBar in sync with position of layer onscroll
scrollObj.prototype.updateScrollbar = function(x, y) {
	var nx, ny;
	if ( this.vBarId ) {
		if (!this.maxY) return;
		ny = -( y * ( (this.vbar.maxY - this.vbar.minY) / this.maxY ) - this.vbar.minY );
		ny = Math.min( Math.max(ny, this.vbar.minY), this.vbar.maxY);
		nx = parseInt(this.vbar.style.left);
		this.vbar.style.left = nx + "px"; this.vbar.style.top = ny + "px";
	} if ( this.hBarId ) {
		if (!this.maxX) return;
		nx = -( x * ( (this.hbar.maxX - this.hbar.minX) / this.maxX ) - this.hbar.minX );
		nx = Math.min( Math.max(nx, this.hbar.minX), this.hbar.maxX);
		ny = parseInt(this.hbar.style.top);
		this.hbar.style.left = nx + "px"; this.hbar.style.top = ny + "px";
	}

}

// Restore dragBar to start position when loading new layer
scrollObj.prototype.restoreScrollbars = function() {
	var bar;
	if (this.vBarId) {
		bar = document.getElementById(this.vBarId);
		bar.style.left = bar.minX + "px"; bar.style.top = bar.minY + "px";
	}
	if (this.hBarId) {
		bar = document.getElementById(this.hBarId);
		bar.style.left = bar.minX + "px"; bar.style.top = bar.minY + "px";
	}
}

// Size dragBar in proportion to size of content in layer
// called on_load of layer if bSizeDragBar prop true
scrollObj.prototype.setBarSize = function() {
	var bar;
	var lyr = document.getElementById(this.lyrId);
	var wn = document.getElementById(this.id);
	if (this.vBarId) {
		bar = document.getElementById(this.vBarId);
		bar.style.height = (lyr.offsetHeight > wn.offsetHeight)? bar.trkHt / ( lyr.offsetHeight / wn.offsetHeight ) + "px": bar.trkHt - 2*bar.minY + "px";
		bar.maxY = bar.trkHt - bar.offsetHeight - bar.minY;
	}
	if (this.hBarId) {
		bar = document.getElementById(this.hBarId);
		bar.style.width = (this.wd > wn.offsetWidth)? bar.trkWd / ( this.wd / wn.offsetWidth ) + "px": bar.trkWd - 2*bar.minX + "px";
		bar.maxX = bar.trkWd - bar.offsetWidth - bar.minX;
	}
}

// called from load method
scrollObj.prototype.on_load = function() {
	this.restoreScrollbars();
	if (this.bSizeDragBar) this.setBarSize();
}

scrollObj.prototype.on_scroll = scrollObj.prototype.on_slide = function(x,y) { this.updateScrollbar(x,y); }

// obtain and discard references to relevant dragBar
scrollObj.prototype.on_scroll_start = scrollObj.prototype.on_slide_start = function() {
	if ( this.vBarId ) this.vbar = document.getElementById(this.vBarId);
	if ( this.hBarId ) this.hbar = document.getElementById(this.hBarId);
}

scrollObj.prototype.on_scroll_end = scrollObj.prototype.on_slide_end = function(x, y) {
	this.updateScrollbar(x,y);
	this.lyr = null; this.bar = null;
}


var dw_event = {
	add: function(obj, etype, fp, cap) {
		cap = cap || false;
		if (obj.addEventListener) obj.addEventListener(etype, fp, cap);
		else if (obj.attachEvent) obj.attachEvent("on" + etype, fp);
	},

	remove: function(obj, etype, fp, cap) {
		cap = cap || false;
		if (obj.removeEventListener) obj.removeEventListener(etype, fp, cap);
		else if (obj.detachEvent) obj.detachEvent("on" + etype, fp);
	},

	DOMit: function(e) {
		e = e? e: window.event;
		e.tgt = e.srcElement? e.srcElement: e.target;
		
		if (!e.preventDefault) e.preventDefault = function () { return false; }
		if (!e.stopPropagation) e.stopPropagation = function () { if (window.event) window.event.cancelBubble = true; }
				
		return e;
	}

}