//--
//-- DOM utilities - many derived from www.quirksmode.org
//--

/* This can be trimmed down to a required subset of the original TiddlyWiki Dom.js */

function drawGradient(place,horiz,locolors,hicolors)
{
	if(!hicolors)
		hicolors = locolors;
	for(var t=0; t<= 100; t+=2) {
		var bar = document.createElement("div");
		place.appendChild(bar);
		bar.style.position = "absolute";
		bar.style.left = horiz ? t + "%" : 0;
		bar.style.top = horiz ? 0 : t + "%";
		bar.style.width = horiz ? (101-t) + "%" : "100%";
		bar.style.height = horiz ? "100%" : (101-t) + "%";
		bar.style.zIndex = -1;
		var p = t/100*(locolors.length-1);
		bar.style.backgroundColor = hicolors[Math.floor(p)].mix(locolors[Math.ceil(p)],p-Math.floor(p)).toString();
	}
}

function createTiddlyText(parent,text)
{
	return parent.appendChild(document.createTextNode(text));
}

function createTiddlyCheckbox(parent,caption,checked,onChange)
{
	var cb = document.createElement("input");
	cb.setAttribute("type","checkbox");
	cb.onclick = onChange;
	parent.appendChild(cb);
	cb.checked = checked;
	cb.className = "chkOptionInput";
	if(caption)
		wikify(caption,parent);
	return cb;
}

function createTiddlyElement(parent,element,id,className,text,attribs)
{
	var e = document.createElement(element);
	if(className != null)
		e.className = className;
	if(id != null)
		e.setAttribute("id",id);
	if(text != null)
		e.appendChild(document.createTextNode(text));
	if(attribs) {
		for(var n in attribs) {
			e.setAttribute(n,attribs[n]);
		}
	}
	if(parent != null)
		parent.appendChild(e);
	return e;
}

//# Add an event handler
//# Thanks to John Resig, via QuirksMode
function addEvent(obj,type,fn)
{
	if(obj.attachEvent) {
		obj['e'+type+fn] = fn;
		obj[type+fn] = function(){obj['e'+type+fn](window.event);};
		obj.attachEvent('on'+type,obj[type+fn]);
	} else {
		obj.addEventListener(type,fn,false);
	}
}

//# Remove  an event handler
//# Thanks to John Resig, via QuirksMode
function removeEvent(obj,type,fn)
{
	if(obj.detachEvent) {
		obj.detachEvent('on'+type,obj[type+fn]);
		obj[type+fn] = null;
	} else {
		obj.removeEventListener(type,fn,false);
	}
}

function addClass(e,className)
{
	var currClass = e.className.split(" ");
	if(currClass.indexOf(className) == -1)
		e.className += " " + className;
}

function removeClass(e,className)
{
	var currClass = e.className.split(" ");
	var i = currClass.indexOf(className);
	while(i != -1) {
		currClass.splice(i,1);
		i = currClass.indexOf(className);
	}
	e.className = currClass.join(" ");
}

function hasClass(e,className)
{
	if(e.className) {
		if(e.className.split(" ").indexOf(className) != -1)
			return true;
	}
	return false;
}

// Find the closest relative with a given property value (property defaults to tagName, relative defaults to parentNode)
function findRelated(e,value,name,relative)
{
	name = name ? name : "tagName";
	relative = relative ? relative : "parentNode";
	if(name == "className") {
		while(e && !hasClass(e,value)) {
			e = e[relative];
		}
	} else {
		while(e && e[name] != value) {
			e = e[relative];
		}
	}
	return e;
}

// Resolve the target object of an event
function resolveTarget(e)
{
	var obj;
	if(e.target)
		obj = e.target;
	else if(e.srcElement)
		obj = e.srcElement;
	if(obj.nodeType == 3) // defeat Safari bug
		obj = obj.parentNode;
	return obj;
}

// Prevent an event from bubbling
function stopEvent(e)
{
	var ev = e ? e : window.event;
	ev.cancelBubble = true;
	if(ev.stopPropagation) ev.stopPropagation();
	return false;
}

// Return the content of an element as plain text with no formatting
function getPlainText(e)
{
	var text = "";
	if(e.innerText)
		text = e.innerText;
	else if(e.textContent)
		text = e.textContent;
	return text;
}

// Get the scroll position for window.scrollTo necessary to scroll a given element into view
function ensureVisible(e)
{
	var posTop = findPosY(e);
	var posBot = posTop + e.offsetHeight;
	var winTop = findScrollY();
	var winHeight = findWindowHeight();
	var winBot = winTop + winHeight;
	if(posTop < winTop) {
		return posTop;
	} else if(posBot > winBot) {
		if(e.offsetHeight < winHeight)
			return posTop - (winHeight - e.offsetHeight);
		else
			return posTop;
	} else {
		return winTop;
	}
}

// Get the current width of the display window
function findWindowWidth()
{
	return window.innerWidth ? window.innerWidth : document.documentElement.clientWidth;
}

// Get the current height of the display window
function findWindowHeight()
{
	return window.innerHeight ? window.innerHeight : document.documentElement.clientHeight;
}

// Get the current horizontal page scroll position
function findScrollX()
{
	return window.scrollX ? window.scrollX : document.documentElement.scrollLeft;
}

// Get the current vertical page scroll position
function findScrollY()
{
	return window.scrollY ? window.scrollY : document.documentElement.scrollTop;
}

function findPosX(obj)
{
	var curleft = 0;
	while(obj.offsetParent) {
		curleft += obj.offsetLeft;
		obj = obj.offsetParent;
	}
	return curleft;
}

function findPosY(obj)
{
	var curtop = 0;
	while(obj.offsetParent) {
		curtop += obj.offsetTop;
		obj = obj.offsetParent;
	}
	return curtop;
}

// Blur a particular element
function blurElement(e)
{
	if(e != null && e.focus && e.blur) {
		e.focus();
		e.blur();
	}
}

// Create a non-breaking space
function insertSpacer(place)
{
	var e = document.createTextNode(String.fromCharCode(160));
	if(place)
		place.appendChild(e);
	return e;
}

// Remove all children of a node
function removeChildren(e)
{
	while(e && e.hasChildNodes())
		removeNode(e.firstChild);
}

// Remove a node and all it's children
function removeNode(e)
{
	scrubNode(e);
	e.parentNode.removeChild(e);
}

// Remove any event handlers or non-primitve custom attributes
function scrubNode(e)
{
	if(!config.browser.isIE)
		return;
	var att = e.attributes;
	if(att) {
		for(var t=0; t<att.length; t++) {
			var n = att[t].name;
			if(n !== 'style' && (typeof e[n] === 'function' || (typeof e[n] === 'object' && e[n] != null))) {
				try {
					e[n] = null;
				} catch(ex) {
				}
			}
		}
	}
	var c = e.firstChild;
	while(c) {
		scrubNode(c);
		c = c.nextSibling;
	}
}

// Add a stylesheet, replacing any previous custom stylesheet
function setStylesheet(s,id,doc)
{
	if(!id)
		id = "customStyleSheet";
	if(!doc)
		doc = document;
	var n = doc.getElementById(id);
	if(doc.createStyleSheet) {
		// Test for IE's non-standard createStyleSheet method
		if(n)
			n.parentNode.removeChild(n);
		// This failed without the &nbsp;
		doc.getElementsByTagName("head")[0].insertAdjacentHTML("beforeEnd","&nbsp;<style id='" + id + "'>" + s + "</style>");
	} else {
		if(n) {
			n.replaceChild(doc.createTextNode(s),n.firstChild);
		} else {
			n = doc.createElement("style");
			n.type = "text/css";
			n.id = id;
			n.appendChild(doc.createTextNode(s));
			doc.getElementsByTagName("head")[0].appendChild(n);
		}
	}
}

function removeStyleSheet(id)
{
	var e = document.getElementById(id);
	if(e)
		e.parentNode.removeChild(e);
}

// Force the browser to do a document reflow when needed to workaround browser bugs
function forceReflow()
{
	if(config.browser.isGecko) {
		setStylesheet("body {top:0px;margin-top:0px;}","forceReflow");
		setTimeout(function() {setStylesheet("","forceReflow");},1);
	}
}

// Replace the current selection of a textarea or text input and scroll it into view
function replaceSelection(e,text)
{
	if(e.setSelectionRange) {
		var oldpos = e.selectionStart;
		var isRange = e.selectionEnd > e.selectionStart;
		e.value = e.value.substr(0,e.selectionStart) + text + e.value.substr(e.selectionEnd);
		e.setSelectionRange(isRange ? oldpos : oldpos + text.length,oldpos + text.length);
		var linecount = e.value.split('\n').length;
		var thisline = e.value.substr(0,e.selectionStart).split('\n').length-1;
		e.scrollTop = Math.floor((thisline - e.rows / 2) * e.scrollHeight / linecount);
	} else if(document.selection) {
		var range = document.selection.createRange();
		if(range.parentElement() == e) {
			var isCollapsed = range.text == "";
			range.text = text;
			if(!isCollapsed) {
				range.moveStart('character', -text.length);
				range.select();
			}
		}
	}
}

// Returns the text of the given (text) node, possibly merging subsequent text nodes
function getNodeText(e)
{
	var t = "";
	while(e && e.nodeName == "#text") {
		t += e.nodeValue;
		e = e.nextSibling;
	}
	return t;
}

// Returns true if the element e has a given ancestor element
function isDescendant(e,ancestor)
{
	while(e) {
		if(e === ancestor)
			return true;
		e = e.parentNode;
	}
	return false;
}