dom.d

/**
	This is an html DOM implementation, started with cloning
	what the browser offers in Javascript, but going well beyond
	it in convenience.

	If you can do it in Javascript, you can probably do it with
	this module.

	And much more.


	Note: some of the documentation here writes html with added
	spaces. That's because ddoc doesn't bother encoding html output,
	and adding spaces is easier than using LT macros everywhere.


	BTW: this file depends on arsd.characterencodings, so help it
	correctly read files from the internet. You should be able to
	get characterencodings.d from the same place you got this file.
*/
module arsd.dom;

// NOTE: do *NOT* override toString on Element subclasses. It won't work.
// Instead, override writeToAppender();

// FIXME: should I keep processing instructions like <?blah ?> and <!-- blah --> (comments too lol)? I *want* them stripped out of most my output, but I want to be able to parse and create them too.

// Stripping them is useful for reading php as html.... but adding them
// is good for building php.

// I need to maintain compatibility with the way it is now too.

import arsd.characterencodings;

import std.string;
import std.exception;
import std.uri;
import std.array;
import std.range;

//import std.stdio;

// tag soup works for most the crap I know now! If you have two bad closing tags back to back, it might erase one, but meh
// that's rarer than the flipped closing tags that hack fixes so I'm ok with it. (Odds are it should be erased anyway; it's
// most likely a typo so I say kill kill kill.


/// This might belong in another module, but it represents a file with a mime type and some data.
/// Document implements this interface with type = text/html (see Document.contentType for more info)
/// and data = document.toString, so you can return Documents anywhere web.d expects FileResources.
interface FileResource {
	string contentType() const; /// the content-type of the file. e.g. "text/html; charset=utf-8" or "image/png"
	immutable(ubyte)[] getData() const; /// the data
}




// this puts in operators and opDispatch to handle string indexes and properties, forwarding to get and set functions.
mixin template JavascriptStyleDispatch() {
	string opDispatch(string name)(string v = null) if(name != "popFront") { // popFront will make this look like a range. Do not want.
		if(v !is null)
			return set(name, v);
		return get(name);
	}

	string opIndex(string key) const {
		return get(key);
	}

	string opIndexAssign(string value, string field) {
		return set(field, value);
	}

	// FIXME: doesn't seem to work
	string* opBinary(string op)(string key)  if(op == "in") {
		return key in fields;
	}
}

/// A proxy object to do the Element class' dataset property. See Element.dataset for more info.
///
/// Do not create this object directly.
struct DataSet {
	this(Element e) {
		this._element = e;
	}

	private Element _element;
	string set(string name, string value) {
		_element.setAttribute("data-" ~ unCamelCase(name), value);
		return value;
	}

	string get(string name) const {
		return _element.getAttribute("data-" ~ unCamelCase(name));
	}

	mixin JavascriptStyleDispatch!();
}

/// for style, i want to be able to set it with a string like a plain attribute,
/// but also be able to do properties Javascript style.

struct ElementStyle {
	this(Element parent) {
		_element = parent;
	}

	Element _element;

	@property ref inout(string) _attribute() inout {
		auto s = "style" in _element.attributes;
		if(s is null) {
			auto e = cast() _element; // const_cast
			e.attributes["style"] = ""; // we need something to reference
			s = cast(inout) ("style" in e.attributes);
		}

		assert(s !is null);
		return *s;
	}

	alias _attribute this; // this is meant to allow element.style = element.style ~ " string "; to still work.

	string set(string name, string value) {
		if(name.length == 0)
			return value;
		name = unCamelCase(name);
		auto r = rules();
		r[name] = value;

		_attribute = "";
		foreach(k, v; r) {
			if(_attribute.length)
				_attribute ~= " ";
			_attribute ~= k ~ ": " ~ v ~ ";";
		}

		_element.setAttribute("style", _attribute); // this is to trigger the observer call

		return value;
	}
	string get(string name) const {
		name = unCamelCase(name);
		auto r = rules();
		if(name in r)
			return r[name];
		return null;
	}

	string[string] rules() const {
		string[string] ret;
		foreach(rule;  _attribute().split(";")) {
			rule = rule.strip();
			if(rule.length == 0)
				continue;
			auto idx = rule.indexOf(":");
			if(idx == -1)
				ret[rule] = "";
			else {
				auto name = rule[0 .. idx].strip;
				auto value = rule[idx + 1 .. $].strip;

				ret[name] = value;
			}
		}

		return ret;
	}

	mixin JavascriptStyleDispatch!();
}

///.
enum NodeType { Text = 3 }


/// You can use this to do an easy null check or a dynamic cast+null check on any element.
T require(T = Element, string file = __FILE__, int line = __LINE__)(Element e) if(is(T : Element))
	in {}
	out(ret) { assert(ret !is null); }
body {
	auto ret = cast(T) e;
	if(ret is null)
		throw new ElementNotFoundException(T.stringof, "passed value", file, line);
	return ret;
}

/// This represents almost everything in the DOM.
class Element {
	// this is a thing so i can remove observer support if it gets slow
	// I have not implemented all these yet
	private void sendObserverEvent(DomMutationOperations operation, string s1 = null, string s2 = null, Element r = null, Element r2 = null) {
		if(parentDocument is null) return;
		DomMutationEvent me;
		me.operation = operation;
		me.target = this;
		me.relatedString = s1;
		me.relatedString2 = s2;
		me.related = r;
		me.related2 = r2;
		parentDocument.dispatchMutationEvent(me);
	}

	// putting all the members up front

	// this ought to be private. don't use it directly.
	Element[] children;

	/// The name of the tag. Remember, changing this doesn't change the dynamic type of the object.
	string tagName;

	/// This is where the attributes are actually stored. You should use getAttribute, setAttribute, and hasAttribute instead.
	string[string] attributes;

	/// In XML, it is valid to write <tag /> for all elements with no children, but that breaks HTML, so I don't do it here.
	/// Instead, this flag tells if it should be. It is based on the source document's notation and a html element list.
	private bool selfClosed;

	/// Get the parent Document object that contains this element.
	/// It may be null, so remember to check for that.
	Document parentDocument;

	///.
	Element parentNode;

	// the next few methods are for implementing interactive kind of things
	private CssStyle _computedStyle;

	// these are here for event handlers. Don't forget that this library never fires events.
	// (I'm thinking about putting this in a version statement so you don't have the baggage. The instance size of this class is 56 bytes right now.)
	EventHandler[][string] bubblingEventHandlers;
	EventHandler[][string] capturingEventHandlers;
	EventHandler[string] defaultEventHandlers;

	void addEventListener(string event, EventHandler handler, bool useCapture = false) {
		if(event.length > 2 && event[0..2] == "on")
			event = event[2 .. $];

		if(useCapture)
			capturingEventHandlers[event] ~= handler;
		else
			bubblingEventHandlers[event] ~= handler;
	}


	// and now methods

	/// Convenience function to try to do the right thing for HTML. This is the main
	/// way I create elements.
	static Element make(string tagName, string childInfo = null, string childInfo2 = null) {
		bool selfClosed = tagName.isInArray(selfClosedElements);

		Element e;
		// want to create the right kind of object for the given tag...
		switch(tagName) {
			case "table":
				e = new Table(null);
			break;
			case "a":
				e = new Link(null);
			break;
			case "form":
				e = new Form(null);
			break;
			case "tr":
				e = new TableRow(null);
			break;
			case "td", "th":
				e = new TableCell(null, tagName);
			break;
			default:
				e = new Element(null, tagName, null, selfClosed); // parent document should be set elsewhere
		}

		// make sure all the stuff is constructed properly FIXME: should probably be in all the right constructors too
		e.tagName = tagName;
		e.selfClosed = selfClosed;

		if(childInfo !is null)
			switch(tagName) {
				/* html5 convenience tags */
				case "audio":
					if(childInfo.length)
						e.addChild("source", childInfo);
					if(childInfo2 !is null)
						e.appendText(childInfo2);
				break;
				case "source":
					e.src = childInfo;
					if(childInfo2 !is null)
						e.type = childInfo2;
				break;
				/* regular html 4 stuff */
				case "img":
					e.src = childInfo;
					if(childInfo2 !is null)
						e.alt = childInfo2;
				break;
				case "link":
					e.href = childInfo;
					if(childInfo2 !is null)
						e.rel = childInfo2;
				break;
				case "option":
					e.innerText = childInfo;
					if(childInfo2 !is null)
						e.value = childInfo2;
				break;
				case "input":
					e.type = "hidden";
					e.name = childInfo;
					if(childInfo2 !is null)
						e.value = childInfo2;
				break;
				case "a":
					e.innerText = childInfo;
					if(childInfo2 !is null)
						e.href = childInfo2;
				break;
				case "script":
				case "style":
					e.innerRawSource = childInfo;
				break;
				case "meta":
					e.name = childInfo;
					if(childInfo2 !is null)
						e.content = childInfo2;
				break;
				/* generically, assume we were passed text and perhaps class */
				default:
					e.innerText = childInfo;
					if(childInfo2.length)
						e.className = childInfo2;
			}

		return e;
	}


	/// Generally, you don't want to call this yourself - use Element.make or document.createElement instead.
	this(Document _parentDocument, string _tagName, string[string] _attributes = null, bool _selfClosed = false) {
		parentDocument = _parentDocument;
		tagName = _tagName;
		if(_attributes !is null)
			attributes = _attributes;
		selfClosed = _selfClosed;

		version(dom_node_indexes)
			this.dataset.nodeIndex = to!string(&(this.attributes));
	}

	/// Convenience constructor when you don't care about the parentDocument. Note this might break things on the document.
	/// Note also that without a parent document, elements are always in strict, case-sensitive mode.
	this(string _tagName, string[string] _attributes = null) {
		tagName = _tagName;
		if(_attributes !is null)
			attributes = _attributes;
		selfClosed = tagName.isInArray(selfClosedElements);

		// this is meant to reserve some memory. It makes a small, but consistent improvement.
		//children.length = 8;
		//children.length = 0;

		version(dom_node_indexes)
			this.dataset.nodeIndex = to!string(&(this.attributes));
	}

	private this(Document _parentDocument) {
		parentDocument = _parentDocument;

		version(dom_node_indexes)
			this.dataset.nodeIndex = to!string(&(this.attributes));
	}


	/* *******************************
	       Navigating the DOM
	*********************************/

	/// Returns the first child of this element. If it has no children, returns null.
	/// Remember, text nodes are children too.
	@property Element firstChild() {
		return children.length ? children[0] : null;
	}

	///
	@property Element lastChild() {
		return children.length ? children[$ - 1] : null;
	}


	///.
	@property Element previousSibling(string tagName = null) {
		if(this.parentNode is null)
			return null;
		Element ps = null;
		foreach(e; this.parentNode.childNodes) {
			if(e is this)
				break;
			if(tagName == "*" && e.nodeType != NodeType.Text) {
				ps = e;
				break;
			}
			if(tagName is null || e.tagName == tagName)
				ps = e;
		}

		return ps;
	}

	///.
	@property Element nextSibling(string tagName = null) {
		if(this.parentNode is null)
			return null;
		Element ns = null;
		bool mightBe = false;
		foreach(e; this.parentNode.childNodes) {
			if(e is this) {
				mightBe = true;
				continue;
			}
			if(mightBe) {
				if(tagName == "*" && e.nodeType != NodeType.Text) {
					ns = e;
					break;
				}
				if(tagName is null || e.tagName == tagName) {
					ns = e;
					break;
				}
			}
		}

		return ns;
	}


	/// Gets the nearest node, going up the chain, with the given tagName
	/// May return null or throw.
	T getParent(T = Element)(string tagName = null) if(is(T : Element)) {
		if(tagName is null) {
			static if(is(T == Form))
				tagName = "form";
			else static if(is(T == Table))
				tagName = "table";
			else static if(is(T == Table))
				tagName == "a";
		}

		auto par = this.parentNode;
		while(par !is null) {
			if(tagName is null || par.tagName == tagName)
				break;
			par = par.parentNode;
		}

		static if(!is(T == Element)) {
			auto t = cast(T) par;
			if(t is null)
				throw new ElementNotFoundException("", tagName ~ " parent not found");
		} else
			auto t = par;

		return t;
	}

	///.
	Element getElementById(string id) {
		// FIXME: I use this function a lot, and it's kinda slow
		// not terribly slow, but not great.
		foreach(e; tree)
			if(e.id == id)
				return e;
		return null;
	}

	///.
	final SomeElementType requireElementById(SomeElementType = Element, string file = __FILE__, int line = __LINE__)(string id)
	if(
		is(SomeElementType : Element)
	)
	out(ret) {
		assert(ret !is null);
	}
	body {
		auto e = cast(SomeElementType) getElementById(id);
		if(e is null)
			throw new ElementNotFoundException(SomeElementType.stringof, "id=" ~ id, file, line);
		return e;
	}

	///.
	final SomeElementType requireSelector(SomeElementType = Element, string file = __FILE__, int line = __LINE__)(string selector)
	if(
		is(SomeElementType : Element)
	)
	out(ret) {
		assert(ret !is null);
	}
	body {
		auto e = cast(SomeElementType) querySelector(selector);
		if(e is null)
			throw new ElementNotFoundException(SomeElementType.stringof, selector, file, line);
		return e;
	}

	/// Note: you can give multiple selectors, separated by commas.
	/// It will return the first match it finds.
	Element querySelector(string selector) {
		// FIXME: inefficient; it gets all results just to discard most of them
		auto list = getElementsBySelector(selector);
		if(list.length == 0)
			return null;
		return list[0];
	}

	/// a more standards-compliant alias for getElementsBySelector
	Element[] querySelectorAll(string selector) {
		return getElementsBySelector(selector);
	}

	/**
		Does a CSS selector

		* -- all, default if nothing else is there

		tag#id.class.class.class:pseudo[attrib=what][attrib=what] OP selector

		It is all additive

		OP

		space = descendant
		>     = direct descendant
		+     = sibling (E+F Matches any F element immediately preceded by a sibling element E)

		[foo]        Foo is present as an attribute
		[foo="warning"]   Matches any E element whose "foo" attribute value is exactly equal to "warning".
		E[foo~="warning"] Matches any E element whose "foo" attribute value is a list of space-separated values, one of which is exactly equal to "warning"
		E[lang|="en"] Matches any E element whose "lang" attribute has a hyphen-separated list of values beginning (from the left) with "en".

		[item$=sdas] ends with
		[item^-sdsad] begins with

		Quotes are optional here.

		Pseudos:
			:first-child
			:last-child
			:link (same as a[href] for our purposes here)


		There can be commas separating the selector. A comma separated list result is OR'd onto the main.



		This ONLY cares about elements. text, etc, are ignored


		There should be two functions: given element, does it match the selector? and given a selector, give me all the elements
	*/
	Element[] getElementsBySelector(string selector) {
		// FIXME: this function could probably use some performance attention
		// ... but only mildly so according to the profiler in the big scheme of things; probably negligible in a big app.


		bool caseSensitiveTags = true;
		if(parentDocument && parentDocument.loose)
			caseSensitiveTags = false;

		Element[] ret;
		foreach(sel; parseSelectorString(selector, caseSensitiveTags))
			ret ~= sel.getElements(this);
		return ret;
	}

	/// .
	Element[] getElementsByClassName(string cn) {
		// is this correct?
		return getElementsBySelector("." ~ cn);
	}

	///.
	Element[] getElementsByTagName(string tag) {
		if(parentDocument && parentDocument.loose)
			tag = tag.toLower();
		Element[] ret;
		foreach(e; tree)
			if(e.tagName == tag)
				ret ~= e;
		return ret;
	}


	/* *******************************
	          Attributes
	*********************************/

	/**
		Gets the given attribute value, or null if the
		attribute is not set.

		Note that the returned string is decoded, so it no longer contains any xml entities.
	*/
	string getAttribute(string name) const {
		if(parentDocument && parentDocument.loose)
			name = name.toLower();
		auto e = name in attributes;
		if(e)
			return *e;
		else
			return null;
	}

	/**
		Sets an attribute. Returns this for easy chaining
	*/
	Element setAttribute(string name, string value) {
		if(parentDocument && parentDocument.loose)
			name = name.toLower();

		// I never use this shit legitimately and neither should you
		auto it = name.toLower;
		if(it == "href" || it == "src") {
			auto v = value.strip.toLower();
			if(v.startsWith("vbscript:"))
				value = value[9..$];
			if(v.startsWith("javascript:"))
				value = value[11..$];
		}

		attributes[name] = value;

		sendObserverEvent(DomMutationOperations.setAttribute, name, value);

		return this;
	}

	/**
		Returns if the attribute exists.
	*/
	bool hasAttribute(string name) {
		if(parentDocument && parentDocument.loose)
			name = name.toLower();

		if(name in attributes)
			return true;
		else
			return false;
	}

	/**
		Removes the given attribute from the element.
	*/
	Element removeAttribute(string name)
	out(ret) {
		assert(ret is this);
	}
	body {
		if(parentDocument && parentDocument.loose)
			name = name.toLower();
		if(name in attributes)
			attributes.remove(name);

		sendObserverEvent(DomMutationOperations.removeAttribute, name);
		return this;
	}

	/**
		Gets the class attribute's contents. Returns
		an empty string if it has no class.
	*/
	string className() const {
		auto c = getAttribute("class");
		if(c is null)
			return "";
		return c;
	}

	///.
	Element className(string c) {
		setAttribute("class", c);
		return this;
	}

	/**
		Provides easy access to attributes, object style.

		auto element = Element.make("a");
		a.href = "cool.html"; // this is the same as a.setAttribute("href", "cool.html");
		string where = a.href; // same as a.getAttribute("href");
	*/
		// name != "popFront" is so duck typing doesn't think it's a range
	@property string opDispatch(string name)(string v = null) if(name != "popFront") {
		if(v !is null)
			setAttribute(name, v);
		return getAttribute(name);
	}

	/**
		Returns the element's children.
	*/
	@property const(Element[]) childNodes() const {
		return children;
	}

	/// Mutable version of the same
	@property Element[] childNodes() { // FIXME: the above should be inout
		return children;
	}

	/// get all the classes on this element
	@property string[] classes() {
		return split(className, " ");
	}

	/// Adds a string to the class attribute. The class attribute is used a lot in CSS.
	Element addClass(string c) {
		if(hasClass(c))
			return this; // don't add it twice

		string cn = getAttribute("class");
		if(cn.length == 0) {
			setAttribute("class", c);
			return this;
		} else {
			setAttribute("class", cn ~ " " ~ c);
		}

		return this;
	}

	/// Removes a particular class name.
	Element removeClass(string c) {
		if(!hasClass(c))
			return this;
		string n;
		foreach(name; classes) {
			if(c == name)
				continue; // cut it out
			if(n.length)
				n ~= " ";
			n ~= name;
		}

		className = n.strip;

		return this;
	}

	/// Returns whether the given class appears in this element.
	bool hasClass(string c) {
		auto cn = className;

		auto idx = cn.indexOf(c);
		if(idx == -1)
			return false;

		foreach(cla; cn.split(" "))
			if(cla == c)
				return true;
		return false;

		/*
		int rightSide = idx + c.length;

		bool checkRight() {
			if(rightSide == cn.length)
				return true; // it's the only class
			else if(iswhite(cn[rightSide]))
				return true;
			return false; // this is a substring of something else..
		}

		if(idx == 0) {
			return checkRight();
		} else {
			if(!iswhite(cn[idx - 1]))
				return false; // substring
			return checkRight();
		}

		assert(0);
		*/
	}


	/// HTML5's dataset property. It is an alternate view into attributes with the data- prefix.
	///
	/// Given: <a data-my-property="cool" />
	///
	/// We get: assert(a.dataset.myProperty == "cool");
	DataSet dataset() {
		return DataSet(this);
	}

	/// Provides both string and object style (like in Javascript) access to the style attribute.
	@property ElementStyle style() {
		return ElementStyle(this);
	}

	/// This sets the style attribute with a string.
	@property ElementStyle style(string s) {
		this.setAttribute("style", s);
		return this.style();
	}

	private void parseAttributes(string[] whichOnes = null) {
/+
		if(whichOnes is null)
			whichOnes = attributes.keys;
		foreach(attr; whichOnes) {
			switch(attr) {
				case "id":

				break;
				case "class":

				break;
				case "style":

				break;
				default:
					// we don't care about it
			}
		}
+/
	}


	// if you change something here, it won't apply... FIXME const? but changing it would be nice if it applies to the style attribute too though you should use style there.
	///.
	@property CssStyle computedStyle() {
		if(_computedStyle is null) {
			auto style = this.getAttribute("style");
		/* we'll treat shitty old html attributes as css here */
			if(this.hasAttribute("width"))
				style ~= "; width: " ~ this.width;
			if(this.hasAttribute("height"))
				style ~= "; width: " ~ this.height;
			if(this.hasAttribute("bgcolor"))
				style ~= "; background-color: " ~ this.bgcolor;
			if(this.tagName == "body" && this.hasAttribute("text"))
				style ~= "; color: " ~ this.text;
			if(this.hasAttribute("color"))
				style ~= "; color: " ~ this.color;
		/* done */


			_computedStyle = new CssStyle(null, style); // gives at least something to work with
		}
		return _computedStyle;
	}

	/// These properties are useless in most cases, but if you write a layout engine on top of this lib, they may be good
	version(browser) {
		void* expansionHook; ///ditto
		int offsetWidth; ///ditto
		int offsetHeight; ///ditto
		int offsetLeft; ///ditto
		int offsetTop; ///ditto
		Element offsetParent; ///ditto
		bool hasLayout; ///ditto
		int zIndex; ///ditto

		///ditto
		int absoluteLeft() {
			int a = offsetLeft;
			auto p = offsetParent;
			while(p) {
				a += p.offsetLeft;
				p = p.offsetParent;
			}

			return a;
		}

		///ditto
		int absoluteTop() {
			int a = offsetTop;
			auto p = offsetParent;
			while(p) {
				a += p.offsetTop;
				p = p.offsetParent;
			}

			return a;
		}
	}

	// Back to the regular dom functions

    public:


	/* *******************************
	          DOM Mutation
	*********************************/

	/// Removes all inner content from the tag; all child text and elements are gone.
	void removeAllChildren()
		out {
			assert(this.children.length == 0);
		}
	body {
		children = null;
	}
	/// convenience function to quickly add a tag with some text or
	/// other relevant info (for example, it's a src for an <img> element
	/// instead of inner text)
	Element addChild(string tagName, string childInfo = null, string childInfo2 = null)
		in {
			assert(tagName !is null);
		}
		out(e) {
			assert(e.parentNode is this);
			assert(e.parentDocument is this.parentDocument);
		}
	body {
		auto e = Element.make(tagName, childInfo, childInfo2);
		// FIXME (maybe): if the thing is self closed, we might want to go ahead and
		// return the parent. That will break existing code though.
		return appendChild(e);
	}

	/// Another convenience function. Adds a child directly after the current one, returning
	/// the new child.
	///
	/// Between this, addChild, and parentNode, you can build a tree as a single expression.
	Element addSibling(string tagName, string childInfo = null, string childInfo2 = null)
		in {
			assert(tagName !is null);
			assert(parentNode !is null);
		}
		out(e) {
			assert(e.parentNode is this.parentNode);
			assert(e.parentDocument is this.parentDocument);
		}
	body {
		auto e = Element.make(tagName, childInfo, childInfo2);
		return parentNode.insertAfter(this, e);
	}

	/// Convenience function to append text intermixed with other children.
	/// For example: div.addChildren("You can visit my website by ", new Link("mysite.com", "clicking here"), ".");
	/// or div.addChildren("Hello, ", user.name, "!");

	/// See also: appendHtml. This might be a bit simpler though because you don't have to think about escaping.
	void addChildren(T...)(T t) {
		foreach(item; t) {
			static if(is(item : Element))
				appendChild(item);
			else static if (is(isSomeString!(item)))
				appendText(to!string(item));
			else static assert(0, "Cannot pass " ~ typeof(item).stringof ~ " to addChildren");
		}
	}

	///.
	Element addChild(string tagName, Element firstChild)
	in {
		assert(firstChild !is null);
	}
	out(ret) {
		assert(ret !is null);
		assert(ret.parentNode is this);
		assert(firstChild.parentNode is ret);

		assert(ret.parentDocument is this.parentDocument);
		//assert(firstChild.parentDocument is this.parentDocument);
	}
	body {
		auto e = Element.make(tagName);
		e.appendChild(firstChild);
		this.appendChild(e);
		return e;
	}

	Element addChild(string tagName, Html innerHtml)
	in {
	}
	out(ret) {
		assert(ret !is null);
		assert(ret.parentNode is this);
		assert(ret.parentDocument is this.parentDocument);
	}
	body {
		auto e = Element.make(tagName);
		this.appendChild(e);
		e.innerHTML = innerHtml.source;
		return e;
	}


    	/// Appends the given element to this one. The given element must not have a parent already.
	Element appendChild(Element e)
		in {
			assert(e !is null);
			assert(e.parentNode is null);
		}
		out (ret) {
			assert(e.parentNode is this);
			assert(e.parentDocument is this.parentDocument);
			assert(e is ret);
		}
	body {
		selfClosed = false;
		e.parentNode = this;
		e.parentDocument = this.parentDocument;
		children ~= e;

		sendObserverEvent(DomMutationOperations.appendChild, null, null, e);

		return e;
	}

	/// .
	void appendChildren(Element[] children) {
		foreach(ele; children)
			appendChild(ele);
	}

	/// Inserts the second element to this node, right before the first param
	Element insertBefore(in Element where, Element what)
		in {
			assert(where !is null);
			assert(where.parentNode is this);
			assert(what !is null);
			assert(what.parentNode is null);
		}
		out (ret) {
			assert(where.parentNode is this);
			assert(what.parentNode is this);

			assert(what.parentDocument is this.parentDocument);
			assert(ret is what);
		}
	body {
		foreach(i, e; children) {
			if(e is where) {
				children = children[0..i] ~ what ~ children[i..$];
				what.parentDocument = this.parentDocument;
				what.parentNode = this;
				return what;
			}
		}

		return what;

		assert(0);
	}

	///.
	Element insertAfter(in Element where, Element what)
		in {
			assert(where !is null);
			assert(where.parentNode is this);
			assert(what !is null);
			assert(what.parentNode is null);
		}
		out (ret) {
			assert(where.parentNode is this);
			assert(what.parentNode is this);
			assert(what.parentDocument is this.parentDocument);
			assert(ret is what);
		}
	body {
		foreach(i, e; children) {
			if(e is where) {
				children = children[0 .. i + 1] ~ what ~ children[i + 1 .. $];
				what.parentNode = this;
				what.parentDocument = this.parentDocument;
				return what;
			}
		}

		return what;

		assert(0);
	}

	/// swaps one child for a new thing. Returns the old child which is now parentless.
	Element swapNode(Element child, Element replacement)
		in {
			assert(child !is null);
			assert(replacement !is null);
			assert(child.parentNode is this);
		}
		out(ret) {
			assert(ret is child);
			assert(ret.parentNode is null);
			assert(replacement.parentNode is this);
			assert(replacement.parentDocument is this.parentDocument);
		}
	body {
		foreach(ref c; this.children)
			if(c is child) {
				c.parentNode = null;
				c = replacement;
				c.parentNode = this;
				c.parentDocument = this.parentDocument;
				return child;
			}
		assert(0);
	}


	///.
	Element appendText(string text) {
		Element e = new TextNode(parentDocument, text);
		return appendChild(e);
	}

	///.
	@property Element[] childElements() {
		Element[] ret;
		foreach(c; children)
			if(c.nodeType == 1)
				ret ~= c;
		return ret;
	}

	/// Appends the given html to the element, returning the elements appended
	Element[] appendHtml(string html) {
		Document d = new Document("<root>" ~ html ~ "</root>");
		return stealChildren(d.root);
	}

	///.
	void reparent(Element newParent)
		in {
			assert(newParent !is null);
			assert(parentNode !is null);
		}
		out {
			assert(this.parentNode is newParent);
			//assert(isInArray(this, newParent.children));
		}
	body {
		parentNode.removeChild(this);
		newParent.appendChild(this);
	}

	///.
	void insertChildAfter(Element child, Element where)
		in {
			assert(child !is null);
			assert(where !is null);
			assert(where.parentNode is this);
			assert(!selfClosed);
			//assert(isInArray(where, children));
		}
		out {
			assert(child.parentNode is this);
			assert(where.parentNode is this);
			//assert(isInArray(where, children));
			//assert(isInArray(child, children));
		}
	body {
		foreach(i, c; children) {
			if(c is where) {
				i++;
				children = children[0..i] ~ child ~ children[i..$];
				child.parentNode = this;
				child.parentDocument = this.parentDocument;
				break;
			}
		}
	}

	///.
	Element[] stealChildren(Element e, Element position = null)
		in {
			assert(!selfClosed);
			assert(e !is null);
			//if(position !is null)
				//assert(isInArray(position, children));
		}
		out (ret) {
			assert(e.children.length == 0);
			debug foreach(child; ret) {
				assert(child.parentNode is this);
				assert(child.parentDocument is this.parentDocument);
			}
		}
	body {
		foreach(c; e.children) {
			c.parentNode = this;
			c.parentDocument = this.parentDocument;
		}
		if(position is null)
			children ~= e.children;
		else {
			foreach(i, child; children) {
				if(child is position) {
					children = children[0..i] ~
						e.children ~
						children[i..$];
					break;
				}
			}
		}

		auto ret = e.children.dup;
		e.children.length = 0;

		return ret;
	}

    	/// Puts the current element first in our children list. The given element must not have a parent already.
	Element prependChild(Element e)
		in {
			assert(e.parentNode is null);
			assert(!selfClosed);
		}
		out {
			assert(e.parentNode is this);
			assert(e.parentDocument is this.parentDocument);
			assert(children[0] is e);
		}
	body {
		e.parentNode = this;
		e.parentDocument = this.parentDocument;
		children = e ~ children;
		return e;
	}


	/**
		Returns a string containing all child elements, formatted such that it could be pasted into
		an XML file.
	*/
	@property string innerHTML(Appender!string where = appender!string()) const {
		if(children is null)
			return "";

		auto start = where.data.length;

		foreach(child; children) {
			assert(child !is null);

			child.writeToAppender(where);
		}

		return where.data[start .. $];
	}

	/**
		Takes some html and replaces the element's children with the tree made from the string.
	*/
	@property void innerHTML(string html) {
		if(html.length)
			selfClosed = false;

		if(html.length == 0) {
			// I often say innerHTML = ""; as a shortcut to clear it out,
			// so let's optimize that slightly.
			removeAllChildren();
			return;
		}

		auto doc = new Document();
		doc.parse("<innerhtml>" ~ html ~ "</innerhtml>"); // FIXME: this should preserve the strictness of the parent document

		children = doc.root.children;
		foreach(c; children) {
			c.parentNode = this;
			c.parentDocument = this.parentDocument;
		}

		reparentTreeDocuments();

		doc.root.children = null;
	}

	/// ditto
	@property void innerHTML(Html html) {
		this.innerHTML = html.source;
	}

	private void reparentTreeDocuments() {
		foreach(c; this.tree)
			c.parentDocument = this.parentDocument;
	}

	/**
		Replaces this node with the given html string, which is parsed

		Note: this invalidates the this reference, since it is removed
		from the tree.

		Returns the new children that replace this.
	*/
	@property Element[] outerHTML(string html) {
		auto doc = new Document();
		doc.parse("<innerhtml>" ~ html ~ "</innerhtml>"); // FIXME: needs to preserve the strictness

		children = doc.root.children;
		foreach(c; children) {
			c.parentNode = this;
			c.parentDocument = this.parentDocument;
		}


		reparentTreeDocuments();


		stripOut();

		return doc.root.children;
	}

	/// Returns all the html for this element, including the tag itself.
	/// This is equivalent to calling toString().
	@property string outerHTML() {
		return this.toString();
	}

	/// This sets the inner content of the element *without* trying to parse it.
	/// You can inject any code in there; this serves as an escape hatch from the dom.
	///
	/// The only times you might actually need it are for < style > and < script > tags in html.
	/// Other than that, innerHTML and/or innerText should do the job.
	@property void innerRawSource(string rawSource) {
		children.length = 0;
		auto rs = new RawSource(parentDocument, rawSource);
		rs.parentNode = this;

		children ~= rs;
	}

	///.
	Element replaceChild(Element find, Element replace) 
		in {
			assert(find !is null);
			assert(replace !is null);
			assert(replace.parentNode is null);
		}
		out(ret) {
			assert(ret is replace);
			assert(replace.parentNode is this);
			assert(replace.parentDocument is this.parentDocument);
			assert(find.parentNode is null);
		}
	body {
		for(int i = 0; i < children.length; i++) {
			if(children[i] is find) {
				replace.parentNode = this;
				children[i].parentNode = null;
				children[i] = replace;
				replace.parentDocument = this.parentDocument;
				return replace;
			}
		}

		throw new Exception("no such child");
	}

	/**
		Removes the given child from this list.

		Returns the removed element.
	*/
	Element removeChild(Element c)
		in {
			assert(c !is null);
			assert(c.parentNode is this);
		}
		out {
			debug foreach(child; children)
				assert(child !is c);
			assert(c.parentNode is null);
		}
	body {
		foreach(i, e; children) {
			if(e is c) {
				children = children[0..i] ~ children [i+1..$];
				c.parentNode = null;
				return c;
			}
		}

		throw new Exception("no such child");
	}

	/// This removes all the children from this element, returning the old list.
	Element[] removeChildren()
		out (ret) {
			assert(children.length == 0);
			debug foreach(r; ret)
				assert(r.parentNode is null);
		}
	body {
		Element[] oldChildren = children.dup;
		foreach(c; oldChildren)
			c.parentNode = null;

		children.length = 0;

		return oldChildren;
	}

	/**
		Replaces the given element with a whole group.
	*/
	void replaceChild(Element find, Element[] replace)
		in {
			assert(find !is null);
			assert(replace !is null);
			assert(find.parentNode is this);
			debug foreach(r; replace)
				assert(r.parentNode is null);
		}
		out {
			assert(find.parentNode is null);
			assert(children.length >= replace.length);
			debug foreach(child; children)
				assert(child !is find);
			debug foreach(r; replace)
				assert(r.parentNode is this);
		}
	body {
		if(replace.length == 0) {
			removeChild(find);
			return;
		}
		assert(replace.length);
		for(int i = 0; i < children.length; i++) {
			if(children[i] is find) {
				children[i].parentNode = null; // this element should now be dead
				children[i] = replace[0];
				foreach(e; replace) {
					e.parentNode = this;
					e.parentDocument = this.parentDocument;
				}

				children = .insertAfter(children, i, replace[1..$]);

				return;
			}
		}

		throw new Exception("no such child");
	}

	/**
		Strips this tag out of the document, putting its inner html
		as children of the parent.

		For example, given: <p>hello <b>there</b></p>, if you
		call stripOut() on the b element, you'll be left with
		<p>hello there<p>.

		The idea here is to make it easy to get rid of garbage
		markup you aren't interested in.
	*/
	void stripOut()
		in {
			assert(parentNode !is null);
		}
		out {
			assert(parentNode is null);
			assert(children.length == 0);
		}
	body {
		foreach(c; children)
			c.parentNode = null; // remove the parent
		if(children.length)
			parentNode.replaceChild(this, this.children);
		else
			parentNode.removeChild(this);
		this.children.length = 0; // we reparented them all above
	}

	/// shorthand for this.parentNode.removeChild(this) with parentNode null check
	/// if the element already isn't in a tree, it does nothing.
	Element removeFromTree()
		in {

		}
		out(var) {
			assert(this.parentNode is null);
			assert(var is this);
		}
	body {
		if(this.parentNode is null)
			return this;

		this.parentNode.removeChild(this);

		return this;
	}

	/// Wraps this element inside the given element.
	/// It's like this.replaceWith(what); what.appendchild(this);
	///
	/// Given: < b >cool</ b >, if you call b.wrapIn(new Link("site.com", "my site is "));
	/// you'll end up with: < a href="site.com">my site is < b >cool< /b ></ a >.
	Element wrapIn(Element what)
		in {
			assert(what !is null);
		}
		out(ret) {
			assert(this.parentNode is what);
			assert(ret is what);
		}
	body {
		this.replaceWith(what);
		what.appendChild(this);

		return what;
	}

	/// Replaces this element with something else in the tree.
	Element replaceWith(Element e) {
		if(e.parentNode !is null)
			e.parentNode.removeChild(e);
		this.parentNode.replaceChild(this, e);
		return e;
	}

	/**
		Splits the className into an array of each class given
	*/
	string[] classNames() const {
		return className().split(" ");
	}

	/**
		Fetches the first consecutive nodes, if text nodes, concatenated together

		If the first node is not text, returns null.

		See also: directText, innerText
	*/
	string firstInnerText() const {
		string s;
		foreach(child; children) {
			if(child.nodeType != NodeType.Text)
				break;

			s ~= child.nodeValue();
		}
		return s;
	}

	/**
		Fetch the inside text, with all tags stripped out.

		<p>cool <b>api</b> &amp; code dude<p>
		innerText of that is "cool api & code dude".
	*/
	@property string innerText() const {
		string s;
		foreach(child; children) {
			if(child.nodeType != NodeType.Text)
				s ~= child.innerText;
			else
				s ~= child.nodeValue();
		}
		return s;
	}

	/**
		Sets the inside text, replacing all children. You don't
		have to worry about entity encoding.
	*/
	@property void innerText(string text) {
		selfClosed = false;
		Element e = new TextNode(parentDocument, text);
		e.parentNode = this;
		children = [e];
	}

	/**
		Returns the text directly under this element,
		not recursively like innerText.

		See also: firstInnerText
	*/
	@property string directText() {
		string ret;
		foreach(e; children) {
			if(e.nodeType == NodeType.Text)
				ret ~= e.nodeValue();
		}

		return ret;
	}

	/**
		Sets the direct text, keeping the same place.

		Unlike innerText, this does *not* remove existing
		elements in the element.

		It only replaces the first text node it sees.

		If there are no text nodes, it calls appendText

		So, given (ignore the spaces in the tags):
			< div > < img > text here < /div >

		it will keep the img, and replace the "text here".
	*/
	@property void directText(string text) {
		foreach(e; children) {
			if(e.nodeType == NodeType.Text) {
				auto it = cast(TextNode) e;
				it.contents = text;
				return;
			}
		}

		appendText(text);
	}

	/**
		Strips this node out of the document, replacing it with the given text
	*/
	@property void outerText(string text) {
		parentNode.replaceChild(this, new TextNode(parentDocument, text));
	}

	/**
		Same result as innerText; the tag with all inner tags stripped out
	*/
	@property string outerText() const {
		return innerText();
	}


	/* *******************************
	          Miscellaneous
	*********************************/

	/// This is a full clone of the element
	@property Element cloned()
	/+
		out(ret) {
			// FIXME: not sure why these fail...
			assert(ret.children.length == this.children.length, format("%d %d", ret.children.length, this.children.length));
			assert(ret.tagName == this.tagName);
		}
	body {
	+/
	{
		auto e = new Element(parentDocument, tagName, attributes.dup, selfClosed);
		foreach(child; children) {
			e.appendChild(child.cloned);
		}

		return e;
	}

	/// Clones the node. If deepClone is true, clone all inner tags too. If false, only do this tag (and its attributes), but it will have no contents.
	Element cloneNode(bool deepClone) {
		if(deepClone)
			return this.cloned;

		// shallow clone
		auto e = new Element(parentDocument, tagName, attributes.dup, selfClosed);
		return e;
	}

	///.
	string nodeValue() const {
		return "";
	}

	// should return int
	///.
	@property int nodeType() const {
		return 1;
	}


	invariant () {
		if(children !is null)
		debug foreach(child; children) {
		//	assert(parentNode !is null);
			assert(child !is null);
			assert(child.parentNode is this, format("%s is not a parent of %s (it thought it was %s)", tagName, child.tagName, child.parentNode is null ? "null" : child.parentNode.tagName));
			assert(child !is this);
			assert(child !is parentNode);
		}

		/+ // only depend on parentNode's accuracy if you shuffle things around and use the top elements - where the contracts guarantee it on out
		if(parentNode !is null) {
			// if you have a parent, you should share the same parentDocument; this is appendChild()'s job
			auto lol = cast(TextNode) this;
			assert(parentDocument is parentNode.parentDocument, lol is null ? this.tagName : lol.contents);
		}
		+/
		//assert(parentDocument !is null); // no more; if it is present, we use it, but it is not required
		// reason is so you can create these without needing a reference to the document
	}

	/**
		Turns the whole element, including tag, attributes, and children, into a string which could be pasted into
		an XML file.
	*/
	override string toString() const {
		return writeToAppender();
	}

	/// This is the actual implementation used by toString. You can pass it a preallocated buffer to save some time.
	/// Returns the string it creates.
	string writeToAppender(Appender!string where = appender!string()) const {
		assert(tagName !is null);

		where.reserve((this.children.length + 1) * 512);

		auto start = where.data.length;

		where.put("<");
		where.put(tagName);

		foreach(n, v ; attributes) {
			assert(n !is null);
			//assert(v !is null);
			where.put(" ");
			where.put(n);
			where.put("=\"");
			htmlEntitiesEncode(v, where);
			where.put("\"");
		}

		if(selfClosed){
			where.put(" />");
			return where.data[start .. $];
		}

		where.put('>');

		innerHTML(where);

		where.put("</");
		where.put(tagName);
		where.put('>');

		return where.data[start .. $];
	}

	/**
		Returns a lazy range of all its children, recursively.
	*/
	@property ElementStream tree() {
		return new ElementStream(this);
	}
}

///.
class DocumentFragment : Element {
	///.
	this(Document _parentDocument) {
		tagName = "#fragment";
		super(_parentDocument);
	}

	///.
	override string writeToAppender(Appender!string where = appender!string()) const {
		return this.innerHTML(where);
	}
}

/// Given text, encode all html entities on it - &, <, >, and ". This function also
/// encodes all 8 bit characters as entities, thus ensuring the resultant text will work
/// even if your charset isn't set right.
///
/// The output parameter can be given to append to an existing buffer. You don't have to
/// pass one; regardless, the return value will be usable for you, with just the data encoded.
string htmlEntitiesEncode(string data, Appender!string output = appender!string()) {
	// if there's no entities, we can save a lot of time by not bothering with the
	// decoding loop. This check cuts the net toString time by better than half in my test.
	// let me know if it made your tests worse though, since if you use an entity in just about
	// every location, the check will add time... but I suspect the average experience is like mine
	// since the check gives up as soon as it can anyway.

	bool shortcut = true;
	foreach(char c; data) {
		// non ascii chars are always higher than 127 in utf8; we'd better go to the full decoder if we see it.
		if(c == '<' || c == '>' || c == '"' || c == '&' || cast(uint) c > 127) {
			shortcut = false; // there's actual work to be done
			break;
		}
	}

	if(shortcut) {
		output.put(data);
		return data;
	}

	auto start = output.data.length;

	output.reserve(data.length + 64); // grab some extra space for the encoded entities

	foreach(dchar d; data) {
		if(d == '&')
			output.put("&amp;");
		else if (d == '<')
			output.put("&lt;");
		else if (d == '>')
			output.put("&gt;");
		else if (d == '\"')
			output.put("&quot;");
//		else if (d == '\'')
//			output.put("&#39;"); // if you are in an attribute, it might be important to encode for the same reason as double quotes
			// FIXME: should I encode apostrophes too? as &#39;... I could also do space but if your html is so bad that it doesn't
			// quote attributes at all, maybe you deserve the xss. Encoding spaces will make everything really ugly so meh
			// idk about apostrophes though. Might be worth it, might not.
		else if (d < 128 && d > 0)
			output.put(d);
		else
			output.put("&#" ~ std.conv.to!string(cast(int) d) ~ ";");
	}

	//assert(output !is null); // this fails on empty attributes.....
	return output.data[start .. $];

//	data = data.replace("\u00a0", "&nbsp;");
}

/// An alias for htmlEntitiesEncode; it works for xml too
string xmlEntitiesEncode(string data) {
	return htmlEntitiesEncode(data);
}

/// This helper function is used for decoding html entities. It has a hard-coded list of entities and characters.
dchar parseEntity(in dchar[] entity) {
	switch(entity[1..$-1]) {
		case "quot":
			return '"';
		case "apos":
			return '\'';
		case "lt":
			return '<';
		case "gt":
			return '>';
		case "amp":
			return '&';
		// the next are html rather than xml
		/*
		case "cent":
		case "pound":
		case "sect":
		case "deg":
		case "micro"
		*/
		case "hellip":
			return '\u2026';
		case "laquo":
			return '\u00ab';
		case "raquo":
			return '\u00bb';
		case "lsquo":
			return '\u2018';
		case "rsquo":
			return '\u2019';
		case "ldquo":
			return '\u201c';
		case "rdquo":
			return '\u201d';
		case "reg":
			return '\u00ae';
		case "trade":
			return '\u2122';
		case "nbsp":
			return '\u00a0';
		case "copy":
			return '\u00a9';
		case "eacute":
			return '\u00e9';
		case "mdash":
			return '\u2014';
		case "Omicron":
			return '\u039f';
		case "omicron":
			return '\u03bf';
		case "middot":
			return '\u00b7';
		// and handling numeric entities
		default:
			if(entity[1] == '#') {
				if(entity[2] == 'x' /*|| (!strict && entity[2] == 'X')*/) {
					auto hex = entity[3..$-1];

					auto p = intFromHex(to!string(hex).toLower());
					return cast(dchar) p;
				} else {
					auto decimal = entity[2..$-1];

					auto p = std.conv.to!int(decimal);
					return cast(dchar) p;
				}
			} else
				return '?';
	}

	assert(0);
}

import std.utf;

/// This takes a string of raw HTML and decodes the entities into a nice D utf-8 string.
/// By default, it uses loose mode - it will try to return a useful string from garbage input too.
/// Set the second parameter to true if you'd prefer it to strictly throw exceptions on garbage input.
string htmlEntitiesDecode(string data, bool strict = false) {
	// this check makes a *big* difference; about a 50% improvement of parse speed on my test.
	if(data.indexOf("&") == -1) // all html entities begin with &
		return data; // if there are no entities in here, we can return the original slice and save some time

	char[] a; // this seems to do a *better* job than appender!

	char[4] buffer;

	bool tryingEntity = false;
	dchar[] entityBeingTried;
	int entityAttemptIndex = 0;

	foreach(dchar ch; data) {
		if(tryingEntity) {
			entityAttemptIndex++;
			entityBeingTried ~= ch;

			if(ch == ';') {
				tryingEntity = false;
				a ~= buffer[0.. std.utf.encode(buffer, parseEntity(entityBeingTried))];
			} else {
				if(entityAttemptIndex >= 9) {
					if(strict)
						throw new Exception("unterminated entity at " ~ to!string(entityBeingTried));
					else {
						tryingEntity = false;
						a ~= to!(char[])(entityBeingTried);
					}
				}
			}
		} else {
			if(ch == '&') {
				tryingEntity = true;
				entityBeingTried = null;
				entityBeingTried ~= ch;
				entityAttemptIndex = 0;
			} else {
				a ~= buffer[0 .. std.utf.encode(buffer, ch)];
			}
		}
	}

	return cast(string) a; // assumeUnique is actually kinda slow, lol
}

///.
class RawSource : Element {

	///.
	this(Document _parentDocument, string s) {
		super(_parentDocument);
		source = s;
		tagName = "#raw";
	}

	///.
	override string nodeValue() const {
		return this.toString();
	}

	///.
	override int nodeType() const {
		return 100;
	}

	///.
	override string writeToAppender(Appender!string where = appender!string()) const {
		where.put(source);
		return source;
	}

	///.
	override Element appendChild(Element e) {
		assert(0, "Cannot append to a text node");
	}


	///.
	string source;
}

///.
class TextNode : Element {
  public:
	///.
	this(Document _parentDocument, string e) {
		super(_parentDocument);
		contents = e;
		tagName = "#text";
	}

	string opDispatch(string name)(string v = null) if(0) { return null; } // text nodes don't have attributes

	///.
	static TextNode fromUndecodedString(Document _parentDocument, string html) {
		auto e = new TextNode(_parentDocument, "");
		e.contents = htmlEntitiesDecode(html, _parentDocument is null ? false : !_parentDocument.loose);
		return e;
	}

	///.
	override @property Element cloned() {
		auto n = new TextNode(parentDocument, contents);
		return n;
	}

	///.
	override string nodeValue() const {
		return this.contents; //toString();
	}

	///.
	override int nodeType() const {
		return NodeType.Text;
	}

	///.
	override string writeToAppender(Appender!string where = appender!string()) const {
		string s;
		if(contents.length)
			s = htmlEntitiesEncode(contents, where);
		else
			s = "";

		assert(s !is null);
		return s;
	}

	///.
	override Element appendChild(Element e) {
		assert(0, "Cannot append to a text node");
	}

	///.
	string contents;
	// alias contents content; // I just mistype this a lot, 
}

/**
	There are subclasses of Element offering improved helper
	functions for the element in HTML.
*/

///.
class Link : Element {

	///.
	this(Document _parentDocument) {
		super(_parentDocument);
		this.tagName = "a";
	}


	///.
	this(string href, string text) {
		super("a");
		setAttribute("href", href);
		innerText = text;
	}
/+
	/// Returns everything in the href EXCEPT the query string
	@property string targetSansQuery() {

	}

	///.
	@property string domainName() {

	}

	///.
	@property string path
+/
	/// This gets a variable from the URL's query string.
	string getValue(string name) {
		auto vars = variablesHash();
		if(name in vars)
			return vars[name];
		return null;
	}

	private string[string] variablesHash() {
		string href = getAttribute("href");
		if(href is null)
			return null;

		auto ques = href.indexOf("?");
		string str = "";
		if(ques != -1) {
			str = href[ques+1..$];

			auto fragment = str.indexOf("#");
			if(fragment != -1)
				str = str[0..fragment];
		}

		string[] variables = str.split("&");

		string[string] hash;

		foreach(var; variables) {
			auto index = var.indexOf("=");
			if(index == -1)
				hash[var] = "";
			else {
				hash[decodeComponent(var[0..index])] = decodeComponent(var[index + 1 .. $]);
			}
		}

		return hash;
	}

	///.
	/*private*/ void updateQueryString(string[string] vars) {
		string href = getAttribute("href");

		auto question = href.indexOf("?");
		if(question != -1)
			href = href[0..question];

		string frag = "";
		auto fragment = href.indexOf("#");
		if(fragment != -1) {
			frag = href[fragment..$];
			href = href[0..fragment];
		}

		string query = "?";
		bool first = true;
		foreach(name, value; vars) {
			if(!first)
				query ~= "&";
			else
				first = false;

			query ~= encodeComponent(name);
			if(value.length)
				query ~= "=" ~ encodeComponent(value);
		}

		if(query != "?")
			href ~= query;

		href ~= frag;

		setAttribute("href", href);
	}

	/// Sets or adds the variable with the given name to the given value
	/// It automatically URI encodes the values and takes care of the ? and &.
	void setValue(string name, string variable) {
		auto vars = variablesHash();
		vars[name] = variable;

		updateQueryString(vars);
	}

	/// Removes the given variable from the query string
	void removeValue(string name) {
		auto vars = variablesHash();
		vars.remove(name);

		updateQueryString(vars);
	}

	/*
	///.
	override string toString() {

	}

	///.
	override string getAttribute(string name) {
		if(name == "href") {

		} else
			return super.getAttribute(name);
	}
	*/
}

///.
class Form : Element {

	///.
	this(Document _parentDocument) {
		super(_parentDocument);
		tagName = "form";
	}

	// FIXME: doesn't handle arrays; multiple fields can have the same name

	/// Set's the form field's value. For input boxes, this sets the value attribute. For
	/// textareas, it sets the innerText. For radio boxes and select boxes, it removes
	/// the checked/selected attribute from all, and adds it to the one matching the value.
	/// For checkboxes, if the value is non-null and not empty, it checks the box.

	/// If you set a value that doesn't exist, it throws an exception if makeNew is false.
	/// Otherwise, it makes a new input with type=hidden to keep the value.
	void setValue(string field, string value, bool makeNew = true) {
		auto eles = getField(field);
		if(eles.length == 0) {
			if(makeNew) {
				addField(field, value);
				return;
			} else
				throw new Exception("form field does not exist");
		}

		if(eles.length == 1) {
			auto e = eles[0];
			switch(e.tagName) {
				default: assert(0);
				case "textarea":
					e.innerText = value;
				break;
				case "input":
					string type = e.getAttribute("type");
					if(type is null) {
						e.value = value;
						return;
					}
					switch(type) {
						case "checkbox":
						case "radio":
							if(value.length)
								e.setAttribute("checked", "checked");
							else
								e.removeAttribute("checked");
						break;
						default:
							e.value = value;
							return;
					}
				break;
				case "select":
					bool found = false;
					foreach(child; e.tree) {
						if(child.tagName != "option")
							continue;
						string val = child.getAttribute("value");
						if(val is null)
							val = child.innerText;
						if(val == value) {
							child.setAttribute("selected", "selected");
							found = true;
						} else
							child.removeAttribute("selected");
					}

					if(!found) {
						e.addChild("option", value)
						.setAttribute("selected", "selected");
					}
				break;
			}
		} else {
			// assume radio boxes
			foreach(e; eles) {
				string val = e.getAttribute("value");
				//if(val is null)
				//	throw new Exception("don't know what to do with radio boxes with null value");
				if(val == value)
					e.setAttribute("checked", "checked");
				else
					e.removeAttribute("checked");
			}
		}
	}

	/// This takes an array of strings and adds hidden <input> elements for each one of them. Unlike setValue,
	/// it makes no attempt to find and modify existing elements in the form to the new values.
	void addValueArray(string key, string[] arrayOfValues) {
		foreach(arr; arrayOfValues)
			addChild("input", key, arr);
	}

	/// Gets the value of the field; what would be given if it submitted right now. (so
	/// it handles select boxes and radio buttons too). For checkboxes, if a value isn't
	/// given, but it is checked, it returns "checked", since null and "" are indistinguishable
	string getValue(string field) {
		auto eles = getField(field);
		if(eles.length == 0)
			return "";
		if(eles.length == 1) {
			auto e = eles[0];
			switch(e.tagName) {
				default: assert(0);
				case "input":
					if(e.type == "checkbox") {
						if(e.checked)
							return e.value.length ? e.value : "checked";
						return "";
					} else
						return e.value;
				case "textarea":
					return e.innerText;
				case "select":
					foreach(child; e.tree) {
						if(child.tagName != "option")
							continue;
						if(child.selected)
							return child.value;
					}
				break;
			}
		} else {
			// assuming radio
			foreach(e; eles) {
				if(e.checked)
					return e.value;
			}
		}

		return "";
	}

	// FIXME: doesn't handle multiple elements with the same name (except radio buttons)
	///.
	string getPostableData() {
		bool[string] namesDone;

		string ret;
		bool outputted = false;

		foreach(e; getElementsBySelector("[name]")) {
			if(e.name in namesDone)
				continue;

			if(outputted)
				ret ~= "&";
			else
				outputted = true;

			ret ~= std.uri.encodeComponent(e.name) ~ "=" ~ std.uri.encodeComponent(getValue(e.name));

			namesDone[e.name] = true;
		}

		return ret;
	}

	/// Gets the actual elements with the given name
	Element[] getField(string name) {
		Element[] ret;
		foreach(e; tree) {
			if(e.name == name)
				ret ~= e;
		}
		return ret;
	}

	/// Grabs the <label> with the given for tag, if there is one.
	Element getLabel(string forId) {
		foreach(e; tree)
			if(e.tagName == "label" && e.getAttribute("for") == forId)
				return e;
		return null;
	}

	/// Adds a new INPUT field to the end of the form with the given attributes.
	Element addField(string name, string value, string type = "hidden") {
		auto e = new Element(parentDocument, "input", null, true);
		e.name = name;
		e.value = value;
		e.type = type;

		appendChild(e);

		return e;
	}

	/// Removes the given field from the form. It finds the element and knocks it right out.
	void removeField(string name) {
		foreach(e; getField(name))
			e.parentNode.removeChild(e);
	}

	/+
	/// Returns all form members.
	@property Element[] elements() {

	}

	///.
	string opDispatch(string name)(string v = null)
		// filter things that should actually be attributes on the form
		if( name != "method" && name != "action" && name != "enctype"
		 && name != "style"  && name != "name" && name != "id" && name != "class")
	{

	}
	+/
/+
	void submit() {
		// take its elements and submit them through http
	}
+/
}

import std.conv;

///.
class Table : Element {

	///.
	this(Document _parentDocument) {
		super(_parentDocument);
		tagName = "table";
	}

	///.
	Element th(T)(T t) {
		Element e;
		if(parentDocument !is null)
			e = parentDocument.createElement("th");
		else
			e = Element.make("th");
		static if(is(T == Html))
			e.innerHTML = t;
		else
			e.innerText = to!string(t);
		return e;
	}

	///.
	Element td(T)(T t) {
		Element e;
		if(parentDocument !is null)
			e = parentDocument.createElement("td");
		else
			e = Element.make("td");
		static if(is(T == Html))
			e.innerHTML = t;
		else
			e.innerText = to!string(t);
		return e;
	}

	///.
	Element appendRow(T...)(T t) {
		Element row = Element.make("tr");

		foreach(e; t) {
			static if(is(typeof(e) : Element)) {
				if(e.tagName == "td" || e.tagName == "th")
					row.appendChild(e);
				else {
					Element a = Element.make("td");

					a.appendChild(e);

					row.appendChild(a);
				}
			} else static if(is(typeof(e) == Html)) {
				Element a = Element.make("td");
				a.innerHTML = e.source;
				row.appendChild(a);
			} else {
				Element a = Element.make("td");
				a.innerText = to!string(e);
				row.appendChild(a);
			}
		}

		foreach(e; children) {
			if(e.tagName == "tbody") {
				e.appendChild(row);
				return row;
			}
		}

		appendChild(row);

		return row;
	}

	///.
	Element captionElement() {
		Element cap;
		foreach(c; children) {
			if(c.tagName == "caption") {
				cap = c;
				break;
			}
		}

		if(cap is null) {
			cap = Element.make("caption");
			appendChild(cap);
		}

		return cap;
	}

	///.
	@property string caption() {
		return captionElement().innerText;
	}

	///.
	@property void caption(string text) {
		captionElement().innerText = text;
	}

	/// Gets the logical layout of the table as a rectangular grid of
	/// cells. It considers rowspan and colspan. A cell with a large
	/// span is represented in the grid by being referenced several times.
	/// The tablePortition parameter can get just a <thead>, <tbody>, or
	/// <tfoot> portion if you pass one.
	///
	/// Note: the rectangular grid might include null cells.
	///
	/// This is kinda expensive so you should call once when you want the grid,
	/// then do lookups on the returned array.
	TableCell[][] getGrid(Element tablePortition = null)
		in {
			if(tablePortition is null)
				assert(tablePortition is null);
			else {
				assert(tablePortition !is null);
				assert(tablePortition.parentNode is this);
				assert(
					tablePortition.tagName == "tbody"
					||
					tablePortition.tagName == "tfoot"
					||
					tablePortition.tagName == "thead"
				);
			}
		}
	body {
		if(tablePortition is null)
			tablePortition = this;

		TableCell[][] ret;

		// FIXME: will also return rows of sub tables!
		auto rows = tablePortition.getElementsByTagName("tr");
		ret.length = rows.length;

		int maxLength = 0;

		int insertCell(int row, int position, TableCell cell) {
			if(row >= ret.length)
				return position; // not supposed to happen - a rowspan is prolly too big.

			if(position == -1) {
				position++;
				foreach(item; ret[row]) {
					if(item is null)
						break;
					position++;
				}
			}

			if(position < ret[row].length)
				ret[row][position] = cell;
			else
				foreach(i; ret[row].length .. position + 1) {
					if(i == position)
						ret[row] ~= cell;
					else
						ret[row] ~= null;
				}
			return position;
		}

		foreach(int i, rowElement; rows) {
			auto row = cast(TableRow) rowElement;
			assert(row !is null);
			assert(i < ret.length);

			int position = 0;
			foreach(cellElement; rowElement.childNodes) {
				auto cell = cast(TableCell) cellElement;
				if(cell is null)
					continue;

				// FIXME: colspan == 0 or rowspan == 0
				// is supposed to mean fill in the rest of
				// the table, not skip it
				foreach(int j; 0 .. cell.colspan) {
					foreach(int k; 0 .. cell.rowspan)
						// if the first row, always append.
						insertCell(k + i, k == 0 ? -1 : position, cell);
					position++;
				}
			}

			if(ret[i].length > maxLength)
				maxLength = cast(int) ret[i].length;
		}

		// want to ensure it's rectangular
		foreach(ref r; ret) {
			foreach(i; r.length .. maxLength)
				r ~= null;
		}

		return ret;
	}
}

/// Represents a table row element - a <tr>
class TableRow : Element {
	///.
	this(Document _parentDocument) {
		super(_parentDocument);
		tagName = "tr";
	}

	// FIXME: the standard says there should be a lot more in here,
	// but meh, I never use it and it's a pain to implement.
}

/// Represents anything that can be a table cell - <td> or <th> html.
class TableCell : Element {
	///.
	this(Document _parentDocument, string _tagName) {
		super(_parentDocument, _tagName);
	}

	@property int rowspan() const {
		int ret = 1;
		auto it = getAttribute("rowspan");
		if(it.length)
			ret = to!int(it);
		return ret;
	}

	@property int colspan() const {
		int ret = 1;
		auto it = getAttribute("colspan");
		if(it.length)
			ret = to!int(it);
		return ret;
	}

	@property int rowspan(int i) {
		setAttribute("rowspan", to!string(i));
		return i;
	}

	@property int colspan(int i) {
		setAttribute("colspan", to!string(i));
		return i;
	}

}


///.
class MarkupError : Exception {

	///.
	this(string message) {
		super(message);
	}
}

/// This is used when you are using one of the require variants of navigation, and no matching element can be found in the tree.
class ElementNotFoundException : Exception {

	/// type == kind of element you were looking for and search == a selector describing the search.
	this(string type, string search, string file = __FILE__, int line = __LINE__) {
		super("Element of type '"~type~"' matching {"~search~"} not found.", file, line);
	}
}

/// The html struct is used to differentiate between regular text nodes and html in certain functions
///
/// Easiest way to construct it is like this: auto html = Html("<p>hello</p>");
struct Html {
	/// This string holds the actual html. Use it to retrieve the contents.
	string source;
}

/// The main document interface, including a html parser.
class Document : FileResource {
	///.
	this(string data, bool caseSensitive = false, bool strict = false) {
		parse(data, caseSensitive, strict);
	}

	/**
		Creates an empty document. It has *nothing* in it at all.
	*/
	this() {

	}

	/// This is just something I'm toying with. Right now, you use opIndex to put in css selectors.
	/// It returns a struct that forwards calls to all elements it holds, and returns itself so you
	/// can chain it.
	///
	/// Example: document["p"].innerText("hello").addClass("modified");
	///
	/// Equivalent to: foreach(e; document.getElementsBySelector("p")) { e.innerText("hello"); e.addClas("modified"); }
	///
	/// Note: always use function calls (not property syntax) and don't use toString in there for best results.
	///
	/// You can also do things like: document["p"]["b"] though tbh I'm not sure why since the selector string can do all that anyway. Maybe
	/// you could put in some kind of custom filter function tho.
	ElementCollection opIndex(string selector) {
		auto e = ElementCollection(this.root);
		return e[selector];
	}

	string _contentType = "text/html; charset=utf-8";

	/// If you're using this for some other kind of XML, you can
	/// set the content type here.
	///
	/// Note: this has no impact on the function of this class.
	/// It is only used if the document is sent via a protocol like HTTP.
	///
	/// This may be called by parse() if it recognizes the data. Otherwise,
	/// if you don't set it, it assumes text/html; charset=utf-8.
	string contentType(string mimeType) {
		_contentType = mimeType;
		return _contentType;
	}

	/// implementing the FileResource interface, useful for sending via
	/// http automatically.
	override string contentType() const {
		return _contentType;
	}

	/// implementing the FileResource interface; it calls toString.
	override immutable(ubyte)[] getData() const {
		return cast(immutable(ubyte)[]) this.toString();
	}


	/// Concatenates any consecutive text nodes
	/*
	void normalize() {
		
	}
	*/

	/// Given the kind of garbage you find on the Internet, try to make sense of it.
	/// Equivalent to document.parse(data, false, false, null);
	/// (Case-insensitive, non-strict, determine character encoding from the data.)

	/// NOTE: this makes no attempt at added security.
	void parseGarbage(string data) {
		parse(data, false, false, null);
	}

	/**
		Take XMLish data and try to make the DOM tree out of it.

		The goal isn't to be perfect, but to just be good enough to
		approximate Javascript's behavior.

		If strict, it throws on something that doesn't make sense.
		(Examples: mismatched tags. It doesn't validate!)
		If not strict, it tries to recover anyway, and only throws
		when something is REALLY unworkable.

		If strict is false, it uses a magic list of tags that needn't
		be closed. If you are writing a document specifically for this,
		try to avoid such - use self closed tags at least. Easier to parse.

		The dataEncoding argument can be used to pass a specific
		charset encoding for automatic conversion. If null (which is NOT
		the default!), it tries to determine from the data itself,
		using the xml prolog or meta tags, and assumes UTF-8 if unsure.

		If this assumption is wrong, it can throw on non-ascii
		characters!


		Note that it previously assumed the data was encoded as UTF-8, which
		is why the dataEncoding argument defaults to that.

		So it shouldn't break backward compatibility.

		But, if you want the best behavior on wild data - figuring it out from the document
		instead of assuming - you'll probably want to change that argument to null.

	*/
	void parse(in string rawdata, bool caseSensitive = false, bool strict = false, string dataEncoding = "UTF-8") {
		// FIXME: this parser could be faster; it's in the top ten biggest tree times according to the profiler
		// of my big app.

		// gotta determine the data encoding. If you know it, pass it in above to skip all this.
		if(dataEncoding is null) {
			dataEncoding = tryToDetermineEncoding(cast(const(ubyte[])) rawdata);
			// it can't tell... probably a random 8 bit encoding. Let's check the document itself.
			// Now, XML and HTML can both list encoding in the document, but we can't really parse
			// it here without changing a lot of code until we know the encoding. So I'm going to
			// do some hackish string checking.
			if(dataEncoding is null) {
				auto dataAsBytes = cast(immutable(ubyte)[]) rawdata;
				// first, look for an XML prolog
				auto idx = indexOfBytes(dataAsBytes, cast(immutable ubyte[]) "encoding=\"");
				if(idx != -1) {
					idx += "encoding=\"".length;
					// we're probably past the prolog if it's this far in; we might be looking at
					// content. Forget about it.
					if(idx > 100)
						idx = -1;
				}
				// if that fails, we're looking for Content-Type http-equiv or a meta charset (see html5)..
				if(idx == -1) {
					idx = indexOfBytes(dataAsBytes, cast(immutable ubyte[]) "charset=");
					if(idx != -1) {
						idx += "charset=".length;
						if(dataAsBytes[idx] == '"')
							idx++;
					}
				}

				// found something in either branch...
				if(idx != -1) {
					// read till a quote or about 12 chars, whichever comes first...
					auto end = idx;
					while(end < dataAsBytes.length && dataAsBytes[end] != '"' && end - idx < 12)
						end++;

					dataEncoding = cast(string) dataAsBytes[idx .. end];
				}
				// otherwise, we just don't know.
			}
		}

		if(dataEncoding is null) {
			if(strict)
				throw new MarkupError("I couldn't figure out the encoding of this document.");
			else
			// if we really don't know by here, it means we already tried UTF-8,
			// looked for utf 16 and 32 byte order marks, and looked for xml or meta
			// tags... let's assume it's Windows-1252, since that's probably the most
			// common aside from utf that wouldn't be labeled.

			dataEncoding = "Windows 1252";
		}

		// and now, go ahead and convert it.

		string data;

		if(!strict) {
			// if we're in non-strict mode, we need to check
			// the document for mislabeling too; sometimes
			// web documents will say they are utf-8, but aren't
			// actually properly encoded. If it fails to validate,
			// we'll assume it's actually Windows encoding - the most
			// likely candidate for mislabeled garbage.
			dataEncoding = dataEncoding.toLower();
			dataEncoding = dataEncoding.replace(" ", "");
			dataEncoding = dataEncoding.replace("-", "");
			dataEncoding = dataEncoding.replace("_", "");
			if(dataEncoding == "utf8") {
				try {
					validate(rawdata);
				} catch(UtfException e) {
					dataEncoding = "Windows 1252";
				}
			}
		}

		if(dataEncoding != "UTF-8")
			data = convertToUtf8(cast(immutable(ubyte)[]) rawdata, dataEncoding);
		else
			data = rawdata;
		assert(data !is null);

		// go through character by character.
		// if you see a <, consider it a tag.
		// name goes until the first non tagname character
		// then see if it self closes or has an attribute

		// if not in a tag, anything not a tag is a big text
		// node child. It ends as soon as it sees a <

		// Whitespace in text or attributes is preserved, but not between attributes

		// &amp; and friends are converted when I know them, left the same otherwise


		// this it should already be done correctly.. so I'm leaving it off to net a ~10% speed boost on my typical test file (really)
		//validate(data); // it *must* be UTF-8 for this to work correctly

		sizediff_t pos = 0;

		clear();

		loose = !caseSensitive;

		bool sawImproperNesting = false;
		bool paragraphHackfixRequired = false;

		int getLineNumber(sizediff_t p) {
			int line = 1;
			foreach(c; data[0..p])
				if(c == '\n')
					line++;
			return line;
		}

		void parseError(string message) {
			throw new MarkupError(format("char %d (line %d): %s", pos, getLineNumber(pos), message));
		}

		void eatWhitespace() {
			while(pos < data.length && (data[pos] == ' ' || data[pos] == '\n' || data[pos] == '\t'))
				pos++;
		}

		string readTagName() {
			// remember to include : for namespaces
			// basically just keep going until >, /, or whitespace
			auto start = pos;
			while(  data[pos] != '>' && data[pos] != '/' &&
				data[pos] != ' ' && data[pos] != '\n' && data[pos] != '\t')
				pos++;

			if(!caseSensitive)
				return toLower(data[start..pos]);
			else
				return data[start..pos];
		}

		string readAttributeName() {
			// remember to include : for namespaces
			// basically just keep going until >, /, or whitespace
			auto start = pos;
			while(  data[pos] != '>' && data[pos] != '/'  && data[pos] != '=' &&
				data[pos] != ' ' && data[pos] != '\n' && data[pos] != '\t')
				pos++;

			if(!caseSensitive)
				return toLower(data[start..pos]);
			else
				return data[start..pos];
		}

		string readAttributeValue() {
			switch(data[pos]) {
				case '\'':
				case '"':
					char end = data[pos];
					pos++;
					auto start = pos;
					while(data[pos] != end)
						pos++;
					string v = htmlEntitiesDecode(data[start..pos], strict);
					pos++; // skip over the end
				return v;
				default:
					if(strict)
						parseError("Attributes must be quoted");
					// read until whitespace or terminator (/ or >)
					auto start = pos;
					while(data[pos] != '>' &&
						// unquoted attributes might be urls, so gotta be careful with them and self-closed elements
						!(data[pos] == '/' && pos + 1 < data.length && data[pos+1] == '>') &&
						data[pos] != ' ' && data[pos] != '\n' && data[pos] != '\t')
					      	pos++;

					string v = htmlEntitiesDecode(data[start..pos], strict);
					// don't skip the end - we'll need it later
					return v;
			}
		}

		TextNode readTextNode() {
			auto start = pos;
			while(pos < data.length && data[pos] != '<') {
				pos++;
			}

			return TextNode.fromUndecodedString(this, data[start..pos]);
		}

		RawSource readCDataNode() {
			auto start = pos;
			while(pos < data.length && data[pos] != '<') {
				pos++;
			}

			return new RawSource(this, data[start..pos]);
		}


		struct Ele {
			int type; // element or closing tag or nothing
			Element element; // for type == 0
			string payload; // for type == 1
		}
		// recursively read a tag
		Ele readElement(string[] parentChain = null) {
			// FIXME: this is the slowest function in this module, by far, even in strict mode.
			// Loose mode should perform decently, but strict mode is the important one.
			if(!strict && parentChain is null)
				parentChain = [];

			if(pos >= data.length)
			{
				if(strict) {
					throw new MarkupError("Gone over the input (is there no root element?), chain: " ~ to!string(parentChain));
				} else {
					if(parentChain.length)
						return Ele(1, null, parentChain[0]); // in loose mode, we just assume the document has ended
					else
						return Ele(4); // signal emptiness upstream
				}
			}

			if(data[pos] != '<') {
				return Ele(0, readTextNode(), null);
			}

			enforce(data[pos] == '<');
			pos++;
			switch(data[pos]) {
				// I don't care about these, so I just want to skip them
				case '!': // might be a comment, a doctype, or a special instruction
					pos++;
						// FIXME: we should store these in the tree too
						// though I like having it stripped out tbh.
					if(data[pos] == '-' && data[pos+1] == '-') {
						// comment
						pos += 2;
						while(data[pos..pos+3] != "-->")
							pos++;
						assert(data[pos] == '-');
						pos++;
						assert(data[pos] == '-');
						pos++;
						assert(data[pos] == '>');
					} else if(data[pos..pos + 7] == "[CDATA[") {
						pos += 7;
						// FIXME: major malfunction possible here
						auto cdataStart = pos;
						auto cdataEnd = pos + data[pos .. $].indexOf("]]>");

						pos = cdataEnd + 3;
						return Ele(0, new TextNode(this, data[cdataStart .. cdataEnd]), null);
					} else
						while(data[pos] != '>')
							pos++;
					pos++; // skip the >
				break;
				case '?':
					char end = data[pos];

				    more:
					pos++; // skip the start
					while(data[pos] != end)
						pos++;
					pos++; // skip the end

					// FIXME: we should actually store this somewhere
						// though I like having it stripped out as well tbh.
					if(data[pos] == '>')
						pos++;
					else
						goto more;
				break;
				case '/': // closing an element
					pos++; // skip the start
					auto p = pos;
					while(data[pos] != '>')
						pos++;
					//writefln("</%s>", data[p..pos]);
					pos++; // skip the '>'

					string tname = data[p..pos-1];
					if(!caseSensitive)
						tname = tname.toLower;

				return Ele(1, null, tname); // closing tag reports itself here
				case ' ': // assume it isn't a real element...
					if(strict)
						parseError("bad markup - improperly placed <");
					else
						return Ele(0, TextNode.fromUndecodedString(this, "<"), null);
				break;
				default:
					string tagName = readTagName();
					string[string] attributes;

					Ele addTag(bool selfClosed) {
						if(selfClosed)
							pos++;
						else {
							if(!strict)
								if(tagName.isInArray(selfClosedElements))
									// these are de-facto self closed
									selfClosed = true;
						}

						if(strict)
						enforce(data[pos] == '>');//, format("got %s when expecting >\nContext:\n%s", data[pos], data[pos - 100 .. pos + 100]));
						else {
							// if we got here, it's probably because a slash was in an
							// unquoted attribute - don't trust the selfClosed value
							if(!selfClosed)
								selfClosed = tagName.isInArray(selfClosedElements);

							while(data[pos] != '>')
								pos++;
						}

						auto whereThisTagStarted = pos; // for better error messages

						pos++;

						auto e = createElement(tagName);
						e.attributes = attributes;
						version(dom_node_indexes) {
							if(e.dataset.nodeIndex.length == 0)
								e.dataset.nodeIndex = to!string(&(e.attributes));
						}
						e.selfClosed = selfClosed;
						e.parseAttributes();


						// HACK to handle script and style as a raw data section as it is in HTML browsers
						if(tagName == "script" || tagName == "style") {
							if(!selfClosed) {
								string closer = "</" ~ tagName ~ ">";
								auto ending = indexOf(data[pos..$], closer);
								if(loose && ending == -1)
									ending = indexOf(data[pos..$], closer.toUpper);
								if(ending == -1)
									throw new Exception("tag " ~ tagName ~ " never closed");
								ending += pos;
								e.innerRawSource = data[pos..ending];
								pos = ending + closer.length;
							}
							return Ele(0, e, null);
						}

						bool closed = selfClosed;

						void considerHtmlParagraphHack(Element n) {
							assert(!strict);
							if(e.tagName == "p" && e.tagName == n.tagName) {
								// html lets you write <p> para 1 <p> para 1
								// but in the dom tree, they should be siblings, not children.
								paragraphHackfixRequired = true;
							}
						}

						//writef("<%s>", tagName);
						while(!closed) {
							Ele n;
							if(strict)
								n = readElement();
							else
								n = readElement(parentChain ~ tagName);

							if(n.type == 4) return n; // the document is empty


							if(n.type == 0) {
								if(!strict)
									considerHtmlParagraphHack(n.element);
								e.appendChild(n.element);
							} else if(n.type == 1) {
								bool found = false;
								if(n.payload != tagName) {
									if(strict)
										parseError(format("mismatched tag: </%s> != <%s> (opened on line %d)", n.payload, tagName, getLineNumber(whereThisTagStarted)));
									else {
										sawImproperNesting = true;
										// this is so we don't drop several levels of awful markup
										if(n.element) {
											if(!strict)
												considerHtmlParagraphHack(n.element);
											e.appendChild(n.element);
											n.element = null;
										}

										// is the element open somewhere up the chain?
										foreach(parent; parentChain)
											if(parent == n.payload) {
												n.element = e;
												return n;
											}

										// if not, this is a text node; we can't fix it up...

										// If it's already in the tree somewhere, assume it is closed by algorithm
										// and we shouldn't output it - odds are the user just flipped a couple tags
										foreach(ele; e.tree) {
											if(ele.tagName == n.payload) {
												found = true;
												break;
											}
										}

										if(!found) // if not found in the tree though, it's probably just text
										e.appendChild(TextNode.fromUndecodedString(this, "</"~n.payload~">"));
									}
								} else {
									if(n.element) {
										if(!strict)
											considerHtmlParagraphHack(n.element);
										e.appendChild(n.element);
									}
								}

								if(n.payload == tagName) // in strict mode, this is always true
									closed = true;
							} else { /*throw new Exception("wtf " ~ tagName);*/ }
						}
						//writef("</%s>\n", tagName);
						return Ele(0, e, null);
					}

					switch(data[pos]) {
						default: assert(0);
						case '/': // self closing tag
							return addTag(true);
						case '>':
							return addTag(false);
						case ' ':
						case '\t':
						case '\n':
							// there might be attributes...
							moreAttributes:
							eatWhitespace();

							switch(data[pos]) {
								case '/': // self closing tag
									return addTag(true);
								case '>': // closed tag; open -- we now read the contents
									return addTag(false);
								default: // it is an attribute
									string attrName = readAttributeName();
									string attrValue = attrName;
									if(data[pos] == '=') {
										pos++;
										attrValue = readAttributeValue();
									}

									if(strict && attrName in attributes)
										throw new MarkupError("Repeated attribute: " ~ attrName);
									attributes[attrName] = attrValue;

									goto moreAttributes;
							}
					}
			}

			return Ele(2, null, null); // this is a <! or <? thing prolly.
			//assert(0);
		}

		eatWhitespace();
		Ele r;
		do {
			r = readElement; // there SHOULD only be one element...
			if(r.type == 4)
				break; // the document is completely empty...
		} while (r.type != 0 || r.element.nodeType != 1); // we look past the xml prologue and doctype

		root = r.element;

		if(root is null)
		{
			if(strict)
				assert(0, "empty document should be impossible in strict mode");
			else
				parse(`<html><head></head><body></body></html>`); // fill in a dummy document in loose mode since that's what browsers do
		}

		if(paragraphHackfixRequired) {
			assert(!strict); // this should never happen in strict mode; it ought to never set the hack flag...

			// in loose mode, we can see some "bad" nesting (it's valid html, but poorly formed xml).
			// It's hard to handle above though because my code sucks. So, we'll fix it here.

			auto iterator = root.tree;
			foreach(ele; iterator) {
				if(ele.parentNode is null)
					continue;

				if(ele.tagName == "p" && ele.parentNode.tagName == ele.tagName) {
					auto shouldBePreviousSibling = ele.parentNode;
					auto holder = shouldBePreviousSibling.parentNode; // this is the two element's mutual holder...
					holder.insertAfter(shouldBePreviousSibling, ele.removeFromTree);
					iterator.currentKilled(); // the current branch can be skipped; we'll hit it soon anyway since it's now next up.
				}
			}
		}
	}

	/* end massive parse function */

	/// Gets the <title> element's innerText, if one exists
	@property string title() {
		bool doesItMatch(Element e) {
			return (e.tagName == "title");
		}

		auto e = findFirst(&doesItMatch);
		if(e)
			return e.innerText();
		return "";
	}

	/// Sets the title of the page, creating a <title> element if needed.
	@property void title(string t) {
		bool doesItMatch(Element e) {
			return (e.tagName == "title");
		}

		auto e = findFirst(&doesItMatch);

		if(!e) {
			e = createElement("title");
			auto heads = getElementsByTagName("head");
			if(heads.length)
				heads[0].appendChild(e);
		}

		if(e)
			e.innerText = t;
	}

	// FIXME: would it work to alias root this; ???? might be a good idea
	/// These functions all forward to the root element. See the documentation in the Element class.
	Element getElementById(string id) {
		return root.getElementById(id);
	}

	/// ditto
	final SomeElementType requireElementById(SomeElementType = Element)(string id)
		if( is(SomeElementType : Element))
		out(ret) { assert(ret !is null); }
	body {
		return root.requireElementById!(SomeElementType)(id);
	}

	/// ditto
	final SomeElementType requireSelector(SomeElementType = Element, string file = __FILE__, int line = __LINE__)(string selector)
		if( is(SomeElementType : Element))
		out(ret) { assert(ret !is null); }
	body {
		return root.requireSelector!(SomeElementType, file, line)(selector);
	}


	/// ditto
	Element querySelector(string selector) {
		return root.querySelector(selector);
	}

	/// ditto
	Element[] querySelectorAll(string selector) {
		return root.querySelectorAll(selector);
	}

	/// ditto
	Element[] getElementsBySelector(string selector) {
		return root.getElementsBySelector(selector);
	}

	/// ditto
	Element[] getElementsByTagName(string tag) {
		return root.getElementsByTagName(tag);
	}

	/** FIXME: btw, this could just be a lazy range...... */
	Element getFirstElementByTagName(string tag) {
		if(loose)
			tag = tag.toLower();
		bool doesItMatch(Element e) {
			return e.tagName == tag;
		}
		return findFirst(&doesItMatch);
	}

	/// This returns the <body> element, if there is one. (It different than Javascript, where it is called 'body', because body is a keyword in D.)
	Element mainBody() {
		return getFirstElementByTagName("body");
	}

	/// this uses a weird thing... it's [name=] if no colon and
	/// [property=] if colon
	string getMeta(string name) {
		string thing = name.indexOf(":") == -1 ? "name" : "property";
		auto e = querySelector("head meta["~thing~"="~name~"]");
		if(e is null)
			return null;
		return e.content;
	}
	
	/// Sets a meta tag in the document header. It is kinda hacky to work easily for both Facebook open graph and traditional html meta tags/
	void setMeta(string name, string value) {
		string thing = name.indexOf(":") == -1 ? "name" : "property";
		auto e = querySelector("head meta["~thing~"="~name~"]");
		if(e is null) {
			e = requireSelector("head").addChild("meta");
			e.setAttribute(thing, name);
		}

		e.content = value;
	}

	///.
	Form[] forms() {
		return cast(Form[]) getElementsByTagName("form");
	}

	///.
	Form createForm() 
		out(ret) {
			assert(ret !is null);
		}
	body {
		return cast(Form) createElement("form");
	}

	///.
	Element createElement(string name) {
		if(loose)
			name = name.toLower();
	
		auto e = Element.make(name);
		e.parentDocument = this;

		return e;

//		return new Element(this, name, null, selfClosed);
	}

	///.
	Element createFragment() {
		return new DocumentFragment(this);
	}

	///.
	Element createTextNode(string content) {
		return new TextNode(this, content);
	}


	///.
	Element findFirst(bool delegate(Element) doesItMatch) {
		Element result;

		bool goThroughElement(Element e) {
			if(doesItMatch(e)) {
				result = e;
				return true;
			}

			foreach(child; e.children) {
				if(goThroughElement(child))
					return true;
			}

			return false;
		}

		goThroughElement(root);

		return result;
	}

	///.
	void clear() {
		root = null;
		loose = false;
	}

	///.
	void setProlog(string d) {
		prolog = d;
	}

	///.
	string prolog = "<!DOCTYPE html>\n";

	///.
	override string toString() const {
		return prolog ~ root.toString();
	}

	///.
	Element root;

	///.
	bool loose;



	// what follows are for mutation events that you can observe
	void delegate(DomMutationEvent)[] eventObservers;

	void dispatchMutationEvent(DomMutationEvent e) {
		foreach(o; eventObservers)
			o(e);
	}
}


/// Specializes Document for handling generic XML. (always uses strict mode, uses xml mime type and file header)
class XmlDocument : Document {
	this(string data) {
		contentType = "text/xml; charset=utf-8";
		prolog = `<?xml version="1.0" encoding="UTF-8"?>` ~ "\n";

		parse(data, true, true);
	}
}



// for the observers
enum DomMutationOperations {
	setAttribute,
	removeAttribute,
	appendChild, // tagname, attributes[], innerHTML
	insertBefore,
	truncateChildren,
	removeChild,
	appendHtml,
	replaceHtml,
	appendText,
	replaceText,
	replaceTextOnly
}

// and for observers too
struct DomMutationEvent {
	DomMutationOperations operation;
	Element target;
	Element related; // what this means differs with the operation
	Element related2;
	string relatedString;
	string relatedString2;
}


private static string[] selfClosedElements = [
	// html 4
	"img", "hr", "input", "br", "col", "link", "meta",
	// html 5
	"source" ];

static import std.conv;

///.
int intFromHex(string hex) {
	int place = 1;
	int value = 0;
	for(sizediff_t a = hex.length - 1; a >= 0; a--) {
		int v;
		char q = hex[a];
		if( q >= '0' && q <= '9')
			v = q - '0';
		else if (q >= 'a' && q <= 'f')
			v = q - 'a' + 10;
		else throw new Exception("Illegal hex character: " ~ q);

		value += v * place;

		place *= 16;
	}

	return value;
}


// CSS selector handling

// EXTENSIONS
// dd - dt means get the dt directly before that dd (opposite of +)                  NOT IMPLEMENTED
// dd -- dt means rewind siblings until you hit a dt, go as far as you need to       NOT IMPLEMENTED
// dt < dl means get the parent of that dt iff it is a dl (usable for "get a dt that are direct children of dl")
// dt << dl  means go as far up as needed to find a dl (you have an element and want its containers)      NOT IMPLEMENTED
// :first  means to stop at the first hit, don't do more (so p + p == p ~ p:first



// CSS4 draft currently says you can change the subject (the element actually returned) by putting a ! at the end of it.
// That might be useful to implement, though I do have parent selectors too.

		///.
		static immutable string[] selectorTokens = [
			// It is important that the 2 character possibilities go first here for accurate lexing
		    "~=", "*=", "|=", "^=", "$=", "!=", // "::" should be there too for full standard
		    "<<", // my any-parent extension (reciprocal of whitespace)
		    " - ", // previous-sibling extension (whitespace required to disambiguate tag-names)
		    ".", ">", "+", "*", ":", "[", "]", "=", "\"", "#", ",", " ", "~", "<"
		]; // other is white space or a name.

		///.
		sizediff_t idToken(string str, sizediff_t position) {
			sizediff_t tid = -1;
			char c = str[position];
			foreach(a, token; selectorTokens)
				if(c == token[0]) {
					if(token.length > 1) {
						if(position + 1 >= str.length   ||   str[position+1] != token[1])
							continue; // not this token
					}
					tid = a;
					break;
				}
			return tid;
		}
	
	///.
	string[] lexSelector(string selector) {

		// FIXME: it doesn't support quoted attributes
		// FIXME: it doesn't support backslash escaped characters
		// FIXME: it should ignore /* comments */
		string[] tokens;
		sizediff_t start = -1;
		bool skip = false;
		// get rid of useless, non-syntax whitespace

		selector = selector.strip;
		selector = selector.replace("\n", " "); // FIXME hack

		selector = selector.replace(" >", ">");
		selector = selector.replace("> ", ">");
		selector = selector.replace(" +", "+");
		selector = selector.replace("+ ", "+");
		selector = selector.replace(" ~", "~");
		selector = selector.replace("~ ", "~");
		selector = selector.replace(" <", "<");
		selector = selector.replace("< ", "<");
			// FIXME: this is ugly ^^^^^. It should just ignore that whitespace somewhere else.

		foreach(i, c; selector) { // kill useless leading/trailing whitespace too
			if(skip) {
				skip = false;
				continue;
			}

			auto tid = idToken(selector, i);

			if(tid == -1) {
				if(start == -1)
					start = i;
			} else {
				if(start != -1) {
					tokens ~= selector[start..i];
					start = -1;
				}
				tokens ~= selectorTokens[tid];
			}

			if (tid != -1 && selectorTokens[tid].length == 2)
				skip = true;
		}
		if(start != -1)
			tokens ~= selector[start..$];

		return tokens;
	}

	///.
	struct SelectorPart {
		string tagNameFilter; ///.
		string[] attributesPresent; /// [attr]
		string[2][] attributesEqual; /// [attr=value]
		string[2][] attributesStartsWith; /// [attr^=value]
		string[2][] attributesEndsWith; /// [attr$=value]
		// split it on space, then match to these
		string[2][] attributesIncludesSeparatedBySpaces; /// [attr~=value]
		// split it on dash, then match to these
		string[2][] attributesIncludesSeparatedByDashes; /// [attr|=value]
		string[2][] attributesInclude; /// [attr*=value]
		string[2][] attributesNotEqual; /// [attr!=value] -- extension by me

		bool firstChild; ///.
		bool lastChild; ///.

		bool emptyElement; ///.
		bool oddChild; ///.
		bool evenChild; ///.

		bool rootElement; ///.

		int separation = -1; /// -1 == only itself; the null selector, 0 == tree, 1 == childNodes, 2 == childAfter, 3 == youngerSibling, 4 == parentOf

		///.
		string toString() {
			string ret;
			switch(separation) {
				default: assert(0);
				case -1: break;
				case 0: ret ~= " "; break;
				case 1: ret ~= ">"; break;
				case 2: ret ~= "+"; break;
				case 3: ret ~= "~"; break;
				case 4: ret ~= "<"; break;
			}
			ret ~= tagNameFilter;
			foreach(a; attributesPresent) ret ~= "[" ~ a ~ "]";
			foreach(a; attributesEqual) ret ~= "[" ~ a[0] ~ "=" ~ a[1] ~ "]";
			foreach(a; attributesEndsWith) ret ~= "[" ~ a[0] ~ "$=" ~ a[1] ~ "]";
			foreach(a; attributesStartsWith) ret ~= "[" ~ a[0] ~ "^=" ~ a[1] ~ "]";
			foreach(a; attributesNotEqual) ret ~= "[" ~ a[0] ~ "!=" ~ a[1] ~ "]";
			foreach(a; attributesInclude) ret ~= "[" ~ a[0] ~ "*=" ~ a[1] ~ "]";
			foreach(a; attributesIncludesSeparatedByDashes) ret ~= "[" ~ a[0] ~ "|=" ~ a[1] ~ "]";
			foreach(a; attributesIncludesSeparatedBySpaces) ret ~= "[" ~ a[0] ~ "~=" ~ a[1] ~ "]";

			if(firstChild) ret ~= ":first-child";
			if(lastChild) ret ~= ":last-child";
			if(emptyElement) ret ~= ":empty";
			if(oddChild) ret ~= ":odd-child";
			if(evenChild) ret ~= ":even-child";
			if(rootElement) ret ~= ":root";

			return ret;
		}

		// USEFUL
		///.
		bool matchElement(Element e) {
			// FIXME: this can be called a lot of times, and really add up in times according to the profiler.
			// Each individual call is reasonably fast already, but it adds up.
			if(e is null) return false;
			if(e.nodeType != 1) return false;

			if(tagNameFilter != "" && tagNameFilter != "*")
				if(e.tagName != tagNameFilter)
					return false;
			if(firstChild) {
				if(e.parentNode is null)
					return false;
				if(e.parentNode.childElements[0] !is e)
					return false;
			}
			if(lastChild) {
				if(e.parentNode is null)
					return false;
				auto ce = e.parentNode.childElements;
				if(ce[$-1] !is e)
					return false;
			}
			if(emptyElement) {
				if(e.children.length)
					return false;
			}
			if(rootElement) {
				if(e.parentNode !is null)
					return false;
			}
			if(oddChild || evenChild) {
				if(e.parentNode is null)
					return false;
				foreach(i, child; e.parentNode.childElements) {
					if(child is e) {
						if(oddChild && !(i&1))
							return false;
						if(evenChild && (i&1))
							return false;
						break;
					}
				}
			}

			bool matchWithSeparator(string attr, string value, string separator) {
				foreach(s; attr.split(separator))
					if(s == value)
						return true;
				return false;
			}

			foreach(a; attributesPresent)
				if(a !in e.attributes)
					return false;
			foreach(a; attributesEqual)
				if(a[0] !in e.attributes || e.attributes[a[0]] != a[1])
					return false;
			foreach(a; attributesNotEqual)
				// if it's null, it's not equal, right?
				//if(a[0] !in e.attributes || e.attributes[a[0]] == a[1])
				if(e.getAttribute(a[0]) == a[1])
					return false;
			foreach(a; attributesInclude)
				if(a[0] !in e.attributes || (e.attributes[a[0]].indexOf(a[1]) == -1))
					return false;
			foreach(a; attributesStartsWith)
				if(a[0] !in e.attributes || !e.attributes[a[0]].startsWith(a[1]))
					return false;
			foreach(a; attributesEndsWith)
				if(a[0] !in e.attributes || !e.attributes[a[0]].endsWith(a[1]))
					return false;
			foreach(a; attributesIncludesSeparatedBySpaces)
				if(a[0] !in e.attributes || !matchWithSeparator(e.attributes[a[0]], a[1], " "))
					return false;
			foreach(a; attributesIncludesSeparatedByDashes)
				if(a[0] !in e.attributes || !matchWithSeparator(e.attributes[a[0]], a[1], "-"))
					return false;

			return true;
		}
	}

	// USEFUL
	///.
	Element[] getElementsBySelectorParts(Element start, SelectorPart[] parts) {
		Element[] ret;
		if(!parts.length) {
			return [start]; // the null selector only matches the start point; it
				// is what terminates the recursion
		}

		auto part = parts[0];
		switch(part.separation) {
			default: assert(0);
			case -1:
			case 0: // tree
				foreach(e; start.tree) {
					if(part.separation == 0 && start is e)
						continue; // space doesn't match itself!
					if(part.matchElement(e)) {
						ret ~= getElementsBySelectorParts(e, parts[1..$]);
					}
				}
			break;
			case 1: // children
				foreach(e; start.childNodes) {
					if(part.matchElement(e)) {
						ret ~= getElementsBySelectorParts(e, parts[1..$]);
					}
				}
			break;
			case 2: // next-sibling
				auto tmp = start.parentNode;
				if(tmp !is null) {
					sizediff_t pos = -1;
					auto children = tmp.childElements;
					foreach(i, child; children) {
						if(child is start) {
							pos = i;
							break;
						}
					}
					assert(pos != -1);
					if(pos + 1 < children.length) {
						auto e = children[pos+1];
						if(part.matchElement(e))
							ret ~= getElementsBySelectorParts(e, parts[1..$]);
					}
				}
			break;
			case 3: // younger sibling
				auto tmp = start.parentNode;
				if(tmp !is null) {
					sizediff_t pos = -1;
					auto children = tmp.childElements;
					foreach(i, child; children) {
						if(child is start) {
							pos = i;
							break;
						}
					}
					assert(pos != -1);
					foreach(e; children[pos+1..$]) {
						if(part.matchElement(e))
							ret ~= getElementsBySelectorParts(e, parts[1..$]);
					}
				}
			break;
			case 4: // immediate parent node, an extension of mine to walk back up the tree
				auto e = start.parentNode;
				if(part.matchElement(e)) {
					ret ~= getElementsBySelectorParts(e, parts[1..$]);
				}
				/*
					Example of usefulness:

					Consider you have an HTML table. If you want to get all rows that have a th, you can do:

					table th < tr

					Get all th descendants of the table, then walk back up the tree to fetch their parent tr nodes
				*/
			break;
			case 5: // any parent note, another extension of mine to go up the tree (backward of the whitespace operator)
				/*
					Like with the < operator, this is best used to find some parent of a particular known element.

					Say you have an anchor inside a 
				*/
		}

		return ret;
	}

	///.
	struct Selector {
		///.
		SelectorPart[] parts;

		///.
		string toString() {
			string ret;
			foreach(part; parts)
				ret ~= part.toString();
			return ret;
		}

		// USEFUL
		///.
		Element[] getElements(Element start) {
			return removeDuplicates(getElementsBySelectorParts(start, parts));
		}

		// USEFUL (but not implemented)
		/// If relativeTo == null, it assumes the root of the parent document.
		bool matchElement(Element e, Element relativeTo = null) {
			// FIXME
			/+
			Element where = e;
			foreach(part; retro(parts)) {
				if(where is relativeTo)
					return false; // at end of line, if we aren't done by now, the match fails
				if(!part.matchElement(where))
					return false; // didn't match

				if(part.selection == 1) // the > operator
					where = where.parentNode;
				else if(part.selection == 0) { // generic parent
					// need to go up the whole chain
				}
			}
			+/
			return true; // if we got here, it is a success
		}

		// the string should NOT have commas. Use parseSelectorString for that instead
		///.
		static Selector fromString(string selector) {
			return parseSelector(lexSelector(selector));
		}
	}

	///.
	Selector[] parseSelectorString(string selector, bool caseSensitiveTags = true) {
		Selector[] ret;
		foreach(s; selector.split(",")) {
			ret ~= parseSelector(lexSelector(s), caseSensitiveTags);
		}

		return ret;
	}

	///.
	Selector parseSelector(string[] tokens, bool caseSensitiveTags = true) {
		Selector s;

		SelectorPart current;
		void commit() {
			// might as well skip null items
			if(current != current.init) {
				s.parts ~= current;

				current = current.init; // start right over
			}
		}
		enum State {
			Starting,
			ReadingClass,
			ReadingId,
			ReadingAttributeSelector,
			ReadingAttributeComparison,
			ExpectingAttributeCloser,
			ReadingPseudoClass,
			ReadingAttributeValue
		}
		State state = State.Starting;
		string attributeName, attributeValue, attributeComparison;
		foreach(token; tokens) {
			sizediff_t tid = -1;
			foreach(i, item; selectorTokens)
				if(token == item) {
					tid = i;
					break;
				}
			final switch(state) {
				case State.Starting: // fresh, might be reading an operator or a tagname
					if(tid == -1) {
						if(!caseSensitiveTags)
							token = token.toLower();
						current.tagNameFilter = token;
					} else {
						// Selector operators
						switch(token) {
							case "*":
								current.tagNameFilter = "*";
							break;
							case " ":
								commit();
								current.separation = 0; // tree
							break;
							case ">":
								commit();
								current.separation = 1; // child
							break;
							case "+":
								commit();
								current.separation = 2; // sibling directly after
							break;
							case "~":
								commit();
								current.separation = 3; // any sibling after
							break;
							case "<":
								commit();
								current.separation = 4; // immediate parent of
							break;
							case "[":
								state = State.ReadingAttributeSelector;
							break;
							case ".":
								state = State.ReadingClass;
							break;
							case "#":
								state = State.ReadingId;
							break;
							case ":":
								state = State.ReadingPseudoClass;
							break;

							default:
								assert(0, token);
						}
					}
				break;
				case State.ReadingClass:
					current.attributesIncludesSeparatedBySpaces ~= ["class", token];
					state = State.Starting;
				break;
				case State.ReadingId:
					current.attributesEqual ~= ["id", token];
					state = State.Starting;
				break;
				case State.ReadingPseudoClass:
					switch(token) {
						case "first-child":
							current.firstChild = true;
						break;
						case "last-child":
							current.lastChild = true;
						break;
						case "only-child":
							current.firstChild = true;
							current.lastChild = true;
						break;
						case "empty":
							// one with no children
							current.emptyElement = true;
						break;
						case "link":
							current.attributesPresent ~= "href";
						break;
						case "root":
							current.rootElement = true;
						break;
						// My extensions
						case "odd-child":
							current.oddChild = true;
						break;
						case "even-child":
							current.evenChild = true;
						break;

						case "visited", "active", "hover", "target", "focus", "checked", "selected":
							current.attributesPresent ~= "nothing";
							// FIXME
						/*
						// defined in the standard, but I don't implement it
						case "not":
						*/
						/+
						// extensions not implemented
						//case "text": // takes the text in the element and wraps it in an element, returning it
						+/
							goto case;
						case "before", "after":
							current.attributesPresent ~= "FIXME";

						break;
						default:
							//if(token.indexOf("lang") == -1)
							//assert(0, token);
						break;
					}
					state = State.Starting;
				break;
				case State.ReadingAttributeSelector:
					attributeName = token;
					attributeComparison = null;
					attributeValue = null;
					state = State.ReadingAttributeComparison;
				break;
				case State.ReadingAttributeComparison:
					// FIXME: these things really should be quotable in the proper lexer...
					if(token != "]") {
						if(token.indexOf("=") == -1) {
							// not a comparison; consider it
							// part of the attribute
							attributeValue ~= token;
						} else {
							attributeComparison = token;
							state = State.ReadingAttributeValue;
						}
						break;
					}
					goto case;
				case State.ExpectingAttributeCloser:
					if(token != "]") {
						// not the closer; consider it part of comparison
						if(attributeComparison == "")
							attributeName ~= token;
						else
							attributeValue ~= token;
						break;
					}

					// FIXME: HACK this chops off quotes from the outside for the comparison
					// for compatibility with real CSS. The lexer should be properly fixed, though.
					// FIXME: when the lexer is fixed, remove this lest you break it moar.
					if(attributeValue.length > 2 && attributeValue[0] == '"' && attributeValue[$-1] == '"')
						attributeValue = attributeValue[1 .. $-1];

					// Selector operators
					switch(attributeComparison) {
						default: assert(0);
						case "":
							current.attributesPresent ~= attributeName;
						break;
						case "=":
							current.attributesEqual ~= [attributeName, attributeValue];
						break;
						case "|=":
							current.attributesIncludesSeparatedByDashes ~= [attributeName, attributeValue];
						break;
						case "~=":
							current.attributesIncludesSeparatedBySpaces ~= [attributeName, attributeValue];
						break;
						case "$=":
							current.attributesEndsWith ~= [attributeName, attributeValue];
						break;
						case "^=":
							current.attributesStartsWith ~= [attributeName, attributeValue];
						break;
						case "*=":
							current.attributesInclude ~= [attributeName, attributeValue];
						break;
						case "!=":
							current.attributesNotEqual ~= [attributeName, attributeValue];
						break;
					}

					state = State.Starting;
				break;
				case State.ReadingAttributeValue:
					attributeValue = token;
					state = State.ExpectingAttributeCloser;
				break;
			}
		}

		commit;

		return s;
	}

///.
Element[] removeDuplicates(Element[] input) {
	Element[] ret;

	bool[Element] already;
	foreach(e; input) {
		if(e in already) continue;
		already[e] = true;
		ret ~= e;
	}

	return ret;
}

// done with CSS selector handling


/// Converts a camel cased propertyName to a css style dashed property-name
string unCamelCase(string a) {
	string ret;
	foreach(c; a)
		if((c >= 'A' && c <= 'Z'))
			ret ~= "-" ~ toLower("" ~ c)[0];
		else
			ret ~= c;
	return ret;
}

/// Translates a css style property-name to a camel cased propertyName
string camelCase(string a) {
	string ret;
	bool justSawDash = false;
	foreach(c; a)
		if(c == '-') {
			justSawDash = true;
		} else {
			if(justSawDash) {
				justSawDash = false;
				ret ~= toUpper("" ~ c);
			} else
				ret ~= c;
		}
	return ret;
}


// FIXME: use the better parser from html.d
/// This is probably not useful to you unless you're writing a browser or something like that.
/// It represents a *computed* style, like what the browser gives you after applying stylesheets, inline styles, and html attributes.
/// From here, you can start to make a layout engine for the box model and have a css aware browser.
class CssStyle {
	///.
	this(string rule, string content) {
		rule = rule.strip;
		content = content.strip;

		if(content.length == 0)
			return;

		originatingRule = rule;
		originatingSpecificity = getSpecificityOfRule(rule); // FIXME: if there's commas, this won't actually work!

		foreach(part; content.split(";")) {
			part = part.strip;
			if(part.length == 0)
				continue;
			auto idx = part.indexOf(":");
			if(idx == -1)
				continue;
				//throw new Exception("Bad css rule (no colon): " ~ part);

			Property p;

			p.name = part[0 .. idx].strip;
			p.value = part[idx + 1 .. $].replace("! important", "!important").replace("!important", "").strip; // FIXME don't drop important
			p.givenExplicitly = true;
			p.specificity = originatingSpecificity;

			properties ~= p;
		}

		foreach(property; properties)
			expandShortForm(property, originatingSpecificity);
	}

	///.
	Specificity getSpecificityOfRule(string rule) {
		Specificity s;
		if(rule.length == 0) { // inline
		//	s.important = 2;
		} else {
			// FIXME
		}

		return s;
	}

	string originatingRule; ///.
	Specificity originatingSpecificity; ///.

	///.
	union Specificity {
		uint score; ///.
		// version(little_endian)
		///.
		struct {
			ubyte tags; ///.
			ubyte classes; ///.
			ubyte ids; ///.
			ubyte important; /// 0 = none, 1 = stylesheet author, 2 = inline style, 3 = user important
		}
	}

	///.
	struct Property {
		bool givenExplicitly; /// this is false if for example the user said "padding" and this is "padding-left"
		string name; ///.
		string value; ///.
		Specificity specificity; ///.
		// do we care about the original source rule?
	}

	///.
	Property[] properties;

	///.
	string opDispatch(string nameGiven)(string value = null) if(nameGiven != "popFront") {
		string name = unCamelCase(nameGiven);
		if(value is null)
			return getValue(name);
		else
			return setValue(name, value, 0x02000000 /* inline specificity */);
	}

	/// takes dash style name
	string getValue(string name) {
		foreach(property; properties)
			if(property.name == name)
				return property.value;
		return null;
	}

	/// takes dash style name
	string setValue(string name, string value, Specificity newSpecificity, bool explicit = true) {
		value = value.replace("! important", "!important");
		if(value.indexOf("!important") != -1) {
			newSpecificity.important = 1; // FIXME
			value = value.replace("!important", "").strip;
		}

		foreach(ref property; properties)
			if(property.name == name) {
				if(newSpecificity.score >= property.specificity.score) {
					property.givenExplicitly = explicit;
					expandShortForm(property, newSpecificity);
					return (property.value = value);
				} else {
					if(name == "display")
					{}//writeln("Not setting ", name, " to ", value, " because ", newSpecificity.score, " < ", property.specificity.score);
					return value; // do nothing - the specificity is too low
				}
			}

		// it's not here...

		Property p;
		p.givenExplicitly = true;
		p.name = name;
		p.value = value;
		p.specificity = originatingSpecificity;

		properties ~= p;
		expandShortForm(p, originatingSpecificity);

		return value;
	}

	private void expandQuadShort(string name, string value, Specificity specificity) {
		auto parts = value.split(" ");
		switch(parts.length) {
			case 1:
				setValue(name ~"-left", parts[0], specificity, false);
				setValue(name ~"-right", parts[0], specificity, false);
				setValue(name ~"-top", parts[0], specificity, false);
				setValue(name ~"-bottom", parts[0], specificity, false);
			break;
			case 2:
				setValue(name ~"-left", parts[1], specificity, false);
				setValue(name ~"-right", parts[1], specificity, false);
				setValue(name ~"-top", parts[0], specificity, false);
				setValue(name ~"-bottom", parts[0], specificity, false);
			break;
			case 3:
				setValue(name ~"-top", parts[0], specificity, false);
				setValue(name ~"-right", parts[1], specificity, false);
				setValue(name ~"-bottom", parts[2], specificity, false);
				setValue(name ~"-left", parts[2], specificity, false);

			break;
			case 4:
				setValue(name ~"-top", parts[0], specificity, false);
				setValue(name ~"-right", parts[1], specificity, false);
				setValue(name ~"-bottom", parts[2], specificity, false);
				setValue(name ~"-left", parts[3], specificity, false);
			break;
			default:
				assert(0, value);
		}
	}

	///.
	void expandShortForm(Property p, Specificity specificity) {
		switch(p.name) {
			case "margin":
			case "padding":
				expandQuadShort(p.name, p.value, specificity);
			break;
			case "border":
			case "outline":
				setValue(p.name ~ "-left", p.value, specificity, false);
				setValue(p.name ~ "-right", p.value, specificity, false);
				setValue(p.name ~ "-top", p.value, specificity, false);
				setValue(p.name ~ "-bottom", p.value, specificity, false);
			break;

			case "border-top":
			case "border-bottom":
			case "border-left":
			case "border-right":
			case "outline-top":
			case "outline-bottom":
			case "outline-left":
			case "outline-right":

			default: {}
		}
	}

	///.
	override string toString() {
		string ret;
		if(originatingRule.length)
			ret = originatingRule ~ " {";

		foreach(property; properties) {
			if(!property.givenExplicitly)
				continue; // skip the inferred shit

			if(originatingRule.length)
				ret ~= "\n\t";
			else
				ret ~= " ";

			ret ~= property.name ~ ": " ~ property.value ~ ";";
		}

		if(originatingRule.length)
			ret ~= "\n}\n";

		return ret;
	}
}

/// This probably isn't useful, unless you're writing a browser or something like that.
/// You might want to look at arsd.html for css macro, nesting, etc., or just use standard css
/// as text.
///
/// The idea, however, is to represent a kind of CSS object model, complete with specificity,
/// that you can apply to your documents to build the complete computedStyle object.
class StyleSheet {
	///.
	CssStyle[] rules;

	///.
	this(string source) {
		// FIXME: handle @ rules and probably could improve lexer
		// add nesting?
		int state;
		string currentRule;
		string currentValue;

		string* currentThing = &currentRule;
		foreach(c; source) {
			handle: switch(state) {
				default: assert(0);
				case 0: // starting - we assume we're reading a rule
					switch(c) {
						case '@':
							state = 4;
						break;
						case '/':
							state = 1;
						break;
						case '{':
							currentThing = &currentValue;
						break;
						case '}':
							if(currentThing is &currentValue) {
								rules ~= new CssStyle(currentRule, currentValue);

								currentRule = "";
								currentValue = "";

								currentThing = &currentRule;
							} else {
								// idk what is going on here.
								// check sveit.com to reproduce
								currentRule = "";
								currentValue = "";
							}
						break;
						default:
							(*currentThing) ~= c;
					}
				break;
				case 1: // expecting *
					if(c == '*')
						state = 2;
					else {
						state = 0;
						(*currentThing) ~= "/" ~ c;
					}
				break;
				case 2: // inside comment
					if(c == '*')
						state = 3;
				break;
				case 3: // expecting / to end comment
					if(c == '/')
						state = 0;
					else
						state = 2; // it's just a comment so no need to append
				break;
				case 4:
					if(c == '{')
						state = 5;
					if(c == ';')
						state = 0; // just skipping import
				break;
				case 5:
					if(c == '}')
						state = 0; // skipping font face probably
			}
		}
	}

	/// Run through the document and apply this stylesheet to it. The computedStyle member will be accurate after this call
	void apply(Document document) {
		foreach(rule; rules) {
			if(rule.originatingRule.length == 0)
				continue; // this shouldn't happen here in a stylesheet
			foreach(element; document.querySelectorAll(rule.originatingRule)) {
				// note: this should be a different object than the inline style
				// since givenExplicitly is likely destroyed here
				auto current = element.computedStyle;

				foreach(item; rule.properties)
					current.setValue(item.name, item.value, item.specificity);
			}
		}
	}
}


/// This is kinda private; just a little utility container for use by the ElementStream class.
final class Stack(T) {
	this() {
		internalLength = 0;
		arr = initialBuffer;
	}

	///.
	void push(T t) {
		if(internalLength >= arr.length) {
			if(arr.length < 4096)
				arr = new T[arr.length * 2];
			else
				arr = new T[arr.length + 4096];
		}

		arr[internalLength] = t;
		internalLength++;
	}

	///.
	T pop() {
		assert(internalLength);
		internalLength--;
		return arr[internalLength];
	}

	///.
	T peek() {
		assert(internalLength);
		return arr[internalLength - 1];
	}

	///.
	bool empty() {
		return internalLength ? false : true;
	}

	///.
	private T[] arr;
	private size_t internalLength;
	private T[64] initialBuffer;
	// the static array is allocated with this object, so if we have a small stack (which we prolly do; dom trees usually aren't insanely deep),
	// using this saves us a bunch of trips to the GC. In my last profiling, I got about a 50x improvement in the push()
	// function thanks to this, and push() was actually one of the slowest individual functions in the code!
}

/// This is the lazy range that walks the tree for you. It tries to go in the lexical order of the source: node, then children from first to last, each recursively.
final class ElementStream {

	///.
	@property Element front() {
		return current.element;
	}

	/// Use Element.tree instead.
	this(Element start) {
		current.element = start;
		current.childPosition = -1;
		isEmpty = false;
		stack = new Stack!(Current);
	}

	/*
		Handle it
		handle its children

	*/

	///.
	void popFront() {
	    more:
	    	if(isEmpty) return;

		// FIXME: the profiler says this function is somewhat slow (noticeable because it can be called a lot of times)

		current.childPosition++;
		if(current.childPosition >= current.element.children.length) {
			if(stack.empty())
				isEmpty = true;
			else {
				current = stack.pop();
				goto more;
			}
		} else {
			stack.push(current);
			current.element = current.element.children[current.childPosition];
			current.childPosition = -1;
		}
	}

	/// You should call this when you remove an element from the tree. It then doesn't recurse into that node and adjusts the current position, keeping the range stable.
	void currentKilled() {
		if(stack.empty) // should never happen
			isEmpty = true;
		else {
			current = stack.pop();
			current.childPosition--; // when it is killed, the parent is brought back a lil so when we popFront, this is then right
		}
	}

	///.
	@property bool empty() {
		return isEmpty;
	}

	private:

	struct Current {
		Element element;
		int childPosition;
	}

	Current current;

	Stack!(Current) stack;

	bool isEmpty;
}



// unbelievable.
// Don't use any of these in your own code. Instead, try to use phobos or roll your own, as I might kill these at any time.
sizediff_t indexOfBytes(immutable(ubyte)[] haystack, immutable(ubyte)[] needle) {
	auto found = std.algorithm.find(haystack, needle);
	if(found.length == 0)
		return -1;
	return haystack.length - found.length;
}

private T[] insertAfter(T)(T[] arr, int position, T[] what) {
	assert(position < arr.length);
	T[] ret;
	ret.length = arr.length + what.length;
	int a = 0;
	foreach(i; arr[0..position+1])
		ret[a++] = i;
	
	foreach(i; what)
		ret[a++] = i;

	foreach(i; arr[position+1..$])
		ret[a++] = i;

	return ret;
}

package bool isInArray(T)(T item, T[] arr) {
	foreach(i; arr)
		if(item == i)
			return true;
	return false;
}

private string[string] dup(in string[string] arr) {
	string[string] ret;
	foreach(k, v; arr)
		ret[k] = v;
	return ret;
}

// I'm just dicking around with this
struct ElementCollection {
	this(Element e) {
		elements = [e];
	}

	this(Element[] e) {
		elements = e;
	}

	Element[] elements;
	//alias elements this; // let it implicitly convert to the underlying array

	ElementCollection opIndex(string selector) {
		ElementCollection ec;
		foreach(e; elements)
			ec.elements ~= e.getElementsBySelector(selector);
		return ec;
	}

	/// Forward method calls to each individual element of the collection
	/// returns this so it can be chained.
	ElementCollection opDispatch(string name, T...)(T t) {
		foreach(e; elements) {
			mixin("e." ~ name)(t);
		}
		return this;
	}

	ElementCollection opBinary(string op : "~")(ElementCollection rhs) {
		return ElementCollection(this.elements ~ rhs.elements);
	}
}


// dom event support, if you want to use it

/// used for DOM events
alias void delegate(Element handlerAttachedTo, Event event) EventHandler;

/// This is a DOM event, like in javascript. Note that this library never fires events - it is only here for you to use if you want it.
class Event {
	this(string eventName, Element target) {
		this.eventName = eventName;
		this.srcElement = target;
	}

	/// Prevents the default event handler (if there is one) from being called
	void preventDefault() {
		defaultPrevented = true;
	}

	/// Stops the event propagation immediately.
	void stopPropagation() {
		propagationStopped = true;
	}

	bool defaultPrevented;
	bool propagationStopped;
	string eventName;

	Element srcElement;
	alias srcElement target;

	Element relatedTarget;

	int clientX;
	int clientY;

	int button;

	bool isBubbling;

	/// this sends it only to the target. If you want propagation, use dispatch() instead.
	void send() {
		if(srcElement is null)
			return;

		auto e = srcElement;

		if(eventName in e.bubblingEventHandlers)
		foreach(handler; e.bubblingEventHandlers[eventName])
			handler(e, this);

		if(!defaultPrevented)
			if(eventName in e.defaultEventHandlers)
				e.defaultEventHandlers[eventName](e, this);
	}

	/// this dispatches the element using the capture -> target -> bubble process
	void dispatch() {
		if(srcElement is null)
			return;

		// first capture, then bubble

		Element[] chain;
		Element curr = srcElement;
		while(curr) {
			auto l = curr;
			chain ~= l;
			curr = curr.parentNode;

		}

		isBubbling = false;

		foreach(e; chain.retro) {
			if(eventName in e.capturingEventHandlers)
			foreach(handler; e.capturingEventHandlers[eventName])
				handler(e, this);

			// the default on capture should really be to always do nothing

			//if(!defaultPrevented)
			//	if(eventName in e.defaultEventHandlers)
			//		e.defaultEventHandlers[eventName](e.element, this);

			if(propagationStopped)
				break;
		}

		isBubbling = true;
		if(!propagationStopped)
		foreach(e; chain) {
			if(eventName in e.bubblingEventHandlers)
			foreach(handler; e.bubblingEventHandlers[eventName])
				handler(e, this);

			if(!defaultPrevented)
				if(eventName in e.defaultEventHandlers)
					e.defaultEventHandlers[eventName](e, this);

			if(propagationStopped)
				break;
		}
	}
}


/*
Copyright: Adam D. Ruppe, 2010 - 2012
License:   <a href="http://www.boost.org/LICENSE_1_0.txt">Boost License 1.0</a>.
Authors: Adam D. Ruppe, with contributions by Nick Sabalausky and Trass3r

        Copyright Adam D. Ruppe 2010-2012.
Distributed under the Boost Software License, Version 1.0.
   (See accompanying file LICENSE_1_0.txt or copy at
        http://www.boost.org/LICENSE_1_0.txt)
*/