/*
 * URLUtils
 * Visit http://createjs.com/ for documentation, updates and examples.
 *
 *
 * Copyright (c) 2012 gskinner.com, inc.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * @module PreloadJS
 */

(function () {

	/**
	 * Utilities that assist with parsing load items, and determining file types, etc.
	 * @class URLUtils
	 */
	var s = {};

	/**
	 * The Regular Expression used to test file URLS for an absolute path.
	 * @property ABSOLUTE_PATH
	 * @type {RegExp}
	 * @static
	 */
	s.ABSOLUTE_PATT = /^(?:\w+:)?\/{2}/i;

	/**
	 * The Regular Expression used to test file URLS for a relative path.
	 * @property RELATIVE_PATH
	 * @type {RegExp}
	 * @static
	 */
	s.RELATIVE_PATT = (/^[./]*?\//i);

	/**
	 * The Regular Expression used to test file URLS for an extension. Note that URIs must already have the query string
	 * removed.
	 * @property EXTENSION_PATT
	 * @type {RegExp}
	 * @static
	 */
	s.EXTENSION_PATT = /\/?[^/]+\.(\w{1,5})$/i;

	/**
	 * Parse a file path to determine the information we need to work with it. Currently, PreloadJS needs to know:
	 * <ul>
	 *     <li>If the path is absolute. Absolute paths start with a protocol (such as `http://`, `file://`, or
	 *     `//networkPath`)</li>
	 *     <li>If the path is relative. Relative paths start with `../` or `/path` (or similar)</li>
	 *     <li>The file extension. This is determined by the filename with an extension. Query strings are dropped, and
	 *     the file path is expected to follow the format `name.ext`.</li>
	 * </ul>
	 *
	 * @method parseURI
	 * @param {String} path
	 * @returns {Object} An Object with an `absolute` and `relative` Boolean values,
	 * 	the pieces of the path (protocol, hostname, port, pathname, search, hash, host)
	 * 	as well as an optional 'extension` property, which is the lowercase extension.
	 *
	 * @static
	 */
	s.parseURI = function (path) {
		var info = {
			absolute: false,
			relative: false,
			protocol: null,
			hostname: null,
			port: null,
			pathname: null,
			search: null,
			hash: null,
			host: null
		};

		if (path == null) { return info; }

		// Inject the path parts.
		var parser = createjs.Elements.a();
		parser.href = path;

		for (var n in info) {
			if (n in parser) {
				info[n] = parser[n];
			}
		}

		// Drop the query string
		var queryIndex = path.indexOf("?");
		if (queryIndex > -1) {
			path = path.substr(0, queryIndex);
		}

		// Absolute
		var match;
		if (s.ABSOLUTE_PATT.test(path)) {
			info.absolute = true;

			// Relative
		} else if (s.RELATIVE_PATT.test(path)) {
			info.relative = true;
		}

		// Extension
		if (match = path.match(s.EXTENSION_PATT)) {
			info.extension = match[1].toLowerCase();
		}

		return info;
	};

	/**
	 * Formats an object into a query string for either a POST or GET request.
	 * @method formatQueryString
	 * @param {Object} data The data to convert to a query string.
	 * @param {Array} [query] Existing name/value pairs to append on to this query.
	 * @static
	 */
	s.formatQueryString = function (data, query) {
		if (data == null) {
			throw new Error("You must specify data.");
		}
		var params = [];
		for (var n in data) {
			params.push(n + "=" + escape(data[n]));
		}
		if (query) {
			params = params.concat(query);
		}
		return params.join("&");
	};

	/**
	 * A utility method that builds a file path using a source and a data object, and formats it into a new path.
	 * @method buildURI
	 * @param {String} src The source path to add values to.
	 * @param {Object} [data] Object used to append values to this request as a query string. Existing parameters on the
	 * path will be preserved.
	 * @returns {string} A formatted string that contains the path and the supplied parameters.
	 * @static
	 */
	s.buildURI = function (src, data) {
		if (data == null) {
			return src;
		}

		var query = [];
		var idx = src.indexOf("?");

		if (idx != -1) {
			var q = src.slice(idx + 1);
			query = query.concat(q.split("&"));
		}

		if (idx != -1) {
			return src.slice(0, idx) + "?" + this.formatQueryString(data, query);
		} else {
			return src + "?" + this.formatQueryString(data, query);
		}
	};

	/**
	 * @method isCrossDomain
	 * @param {LoadItem|Object} item A load item with a `src` property.
	 * @return {Boolean} If the load item is loading from a different domain than the current location.
	 * @static
	 */
	s.isCrossDomain = function (item) {
		var target = createjs.Elements.a();
		target.href = item.src;

		var host = createjs.Elements.a();
		host.href = location.href;

		var crossdomain = (target.hostname != "") &&
			(target.port != host.port ||
			target.protocol != host.protocol ||
			target.hostname != host.hostname);
		return crossdomain;
	};

	/**
	 * @method isLocal
	 * @param {LoadItem|Object} item A load item with a `src` property
	 * @return {Boolean} If the load item is loading from the "file:" protocol. Assume that the host must be local as
	 * well.
	 * @static
	 */
	s.isLocal = function (item) {
		var target = createjs.Elements.a();
		target.href = item.src;
		return target.hostname == "" && target.protocol == "file:";
	};

	createjs.URLUtils = s;

}());