/*
 * Paper.js - The Swiss Army Knife of Vector Graphics Scripting.
 * http://paperjs.org/
 *
 * Copyright (c) 2011 - 2013, Juerg Lehni & Jonathan Puckey
 * http://lehni.org/ & http://jonathanpuckey.com/
 *
 * Distributed under the MIT license. See LICENSE file for details.
 *
 * All rights reserved.
 */

/**
 * @name DomElement
 * @namespace
 * @private
 */
var DomElement = new function() {
	// We use a mix of Bootstrap.js legacy and Bonzo.js magic, ported over and
	// furhter simplified to a subset actually required by Paper.js

	var special = /^(checked|value|selected|disabled)$/i,
		translated = { text: 'textContent', html: 'innerHTML' },
		unitless = { lineHeight: 1, zoom: 1, zIndex: 1, opacity: 1 };

	function create(nodes, parent) {
		var res = [];
		for (var i =  0, l = nodes && nodes.length; i < l;) {
			var el = nodes[i++];
			if (typeof el === 'string') {
				el = document.createElement(el);
			} else if (!el || !el.nodeType) {
				continue;
			}
			// Do we have attributes?
			if (Base.isPlainObject(nodes[i]))
				DomElement.set(el, nodes[i++]);
			// Do we have children?
			if (Array.isArray(nodes[i]))
				create(nodes[i++], el);
			// Are we adding to a parent?
			if (parent)
				parent.appendChild(el);
			res.push(el);
		}
		return res;
	}

	return /** @lends DomElement */{
		create: function(nodes, parent) {
			var isArray = Array.isArray(nodes),
				res = create(isArray ? nodes : arguments, isArray ? parent : null);
			return res.length == 1 ? res[0] : res;
		},

		find: function(selector, root) {
			return (root || document).querySelector(selector);
		},

		findAll: function(selector, root) {
			return (root || document).querySelectorAll(selector);
		},

		get: function(el, key) {
			return el
				? special.test(key)
					? key === 'value' || typeof el[key] !== 'string'
						? el[key]
						: true
					: key in translated
						? el[translated[key]]
						: el.getAttribute(key)
				: null;
		},

		set: function(el, key, value) {
			if (typeof key !== 'string') {
				for (var name in key)
					if (key.hasOwnProperty(name))
						this.set(el, name, key[name]);
			} else if (!el || value === undefined) {
				return el;
			} else if (special.test(key)) {
				el[key] = value;
			} else if (key in translated) {
				el[translated[key]] = value;
			} else if (key === 'style') {
				this.setStyle(el, value);
			} else if (key === 'events') {
				DomEvent.add(el, value);
			} else {
				el.setAttribute(key, value);
			}
			return el;
		},

		getStyles: function(el) {
			// If el is a document (nodeType == 9), use it directly
			var doc = el && el.nodeType !== 9 ? el.ownerDocument : el,
				view = doc && doc.defaultView;
			return view && view.getComputedStyle(el, '');
		},

		getStyle: function(el, key) {
			return el && el.style[key] || this.getStyles(el)[key] || null;
		},

		setStyle: function(el, key, value) {
			if (typeof key !== 'string') {
				for (var name in key)
					if (key.hasOwnProperty(name))
						this.setStyle(el, name, key[name]);
			} else {
				if (/^-?[\d\.]+$/.test(value) && !(key in unitless))
					value += 'px';
				el.style[key] = value;
			}
			return el;
		},

		hasClass: function(el, cls) {
			return new RegExp('\\s*' + cls + '\\s*').test(el.className);
		},

		addClass: function(el, cls) {
			el.className = (el.className + ' ' + cls).trim();
		},

		removeClass: function(el, cls) {
			el.className = el.className.replace(
				new RegExp('\\s*' + cls + '\\s*'), ' ').trim();
		},

		remove: function(el) {
			if (el.parentNode)
				el.parentNode.removeChild(el);
		},

		removeChildren: function(el) {
			while (el.firstChild)
				el.removeChild(el.firstChild);
		},

		getBounds: function(el, viewport) {
			var doc = el.ownerDocument,
				body = doc.body,
				html = doc.documentElement,
				rect;
			try {
				// On IE, for nodes that are not inside the DOM, this throws an
				// exception. Emulate the behavior of all other browsers, which
				// return a rectangle of 0 dimensions.
				rect = el.getBoundingClientRect();
			} catch (e) {
				rect = { left: 0, top: 0, width: 0, height: 0 };
			}
			var x = rect.left - (html.clientLeft || body.clientLeft || 0),
				y = rect.top - (html.clientTop  || body.clientTop  || 0);
			if (!viewport) {
				var view = doc.defaultView;
				x += view.pageXOffset || html.scrollLeft || body.scrollLeft;
				y += view.pageYOffset || html.scrollTop || body.scrollTop;
			}
			return new Rectangle(x, y, rect.width, rect.height);
		},

		getViewportBounds: function(el) {
			var doc = el.ownerDocument,
				view = doc.defaultView,
				html = doc.documentElement;
			return new Rectangle(0, 0, 
				view.innerWidth || html.clientWidth,
				view.innerHeight || html.clientHeight
			);
		},

		getOffset: function(el, viewport) {
			return this.getBounds(el, viewport).getPoint();
		},

		getSize: function(el) {
			return this.getBounds(el, true).getSize();
		},

		/**
		 * Checks if element is invisibile (display: none, ...)
		 */
		isInvisible: function(el) {
			return this.getSize(el).equals(new Size(0, 0));
		},

		/**
		 * Checks if element is visibile in current viewport
		 */
		isInView: function(el) {
			// See if the viewport bounds intersect with the windows rectangle
			// which always starts at 0, 0
			return !this.isInvisible(el) && this.getViewportBounds(el).intersects(
					this.getBounds(el, true));
		},

		/**
		 * Gets the given property from the element, trying out all browser
		 * prefix variants.
		 */
		getPrefixValue: function(el, name) {
			var value = el[name],
				prefixes = ['webkit', 'moz', 'ms', 'o'],
				suffix = name[0].toUpperCase() + name.substring(1);
			for (var i = 0; i < 4 && value == null; i++)
				value = el[prefixes[i] + suffix];
			return value;
		}
	};
};