/**

  * @fileOverview

  * 

  * Grauw URI utilities

  * 

  * See: http://hg.grauw.nl/grauw-lib/file/tip/src/uri.js

  * 

  * @author Laurens Holst (http://www.grauw.nl/)

  * 

  *   Copyright 2010 Laurens Holst

  * 

  *   Licensed under the Apache License, Version 2.0 (the "License");

  *   you may not use this file except in compliance with the License.

  *   You may obtain a copy of the License at

  * 

  *       http://www.apache.org/licenses/LICENSE-2.0

  * 

  *   Unless required by applicable law or agreed to in writing, software

  *   distributed under the License is distributed on an "AS IS" BASIS,

  *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  *   See the License for the specific language governing permissions and

  *   limitations under the License.

  * 

  */

 gl.module('gl.uri', [], function() {

 	/**

 	 * Constructs a URI object.

 	 * @constructor

 	 * @class Implementation of URI parsing and base URI resolving algorithm in RFC 3986.

 	 * @param {string|URI} uri A string or URI object to create the object from.

 	 */

 	var URI = function(vURI) {

 		if (vURI instanceof URI) {	// copy constructor

 			this.scheme = vURI.scheme;

 			this.authority = vURI.authority;

 			this.path = vURI.path;

 			this.query = vURI.query;

 			this.fragment = vURI.fragment;

 		} else if (vURI) { // vURI is URI string or cast to string

 			var c = oParseRegex.exec(vURI);

 			this.scheme = c[1];

 			this.authority = c[2];

 			this.path = c[3];

 			this.query = c[4];

 			this.fragment = c[5];

 		}

 	};

 	// Initial values on the prototype

 	URI.prototype.scheme    = null;

 	URI.prototype.authority = null;

 	URI.prototype.path      = '';

 	URI.prototype.query     = null;

 	URI.prototype.fragment  = null;

 	// Regular expression from RFC 2396 appendix B

 	var oParseRegex = new RegExp('^(?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*)(?:\\?([^#]*))?(?:#(.*))?');

 	/**

 	 * Resolves a relative URI against an absolute base URI.

 	 * Convenience method.

 	 * @param {String} uri the relative URI to resolve

 	 * @param {String} baseURI the base URI (must be absolute) to resolve against

 	 */

 	URI.resolve = function(sURI, sBaseURI) {

 		var oURI = hCache[sURI] || (hCache[sURI] = new URI(sURI));

 		var oBaseURI = hCache[sBaseURI] || (hCache[sBaseURI] = new URI(sBaseURI));

 		return oURI.resolve(oBaseURI).toString();

 	};

 	var hCache = {};

 	/**

 	 * Tests whether the URI is an absolute URI.

 	 * See RFC 3986 section 4.3.

 	 */

 	URI.prototype.isAbsolute = function() {

 		return this.scheme && !this.fragment;

 	};

 	///**

 	//* Extensive validation of the URI against the ABNF in RFC 3986

 	//*/

 	//URI.prototype.validate

 	/**

 	 * Tests whether the URI is a same-document reference.

 	 * See RFC 3986 section 4.4.

 	 * 

 	 * To perform more thorough comparison, you can normalise the URI objects.

 	 */

 	URI.prototype.isSameDocumentAs = function(oURI) {

 		return oURI.scheme == this.scheme &&

 		    oURI.authority == this.authority &&

 		         oURI.path == this.path &&

 		        oURI.query == this.query;

 	};

 	/**

 	 * Simple String Comparison of two URIs.

 	 * See RFC 3986 section 6.2.1.

 	 * 

 	 * To perform more thorough comparison, you can normalise the URI objects.

 	 */

 	URI.prototype.equals = function(oURI) {

 		return this.isSameDocumentAs(oURI) && oURI.fragment == this.fragment;

 	};

 	/**

 	 * Normalizes the URI using syntax-based normalization.

 	 * This includes case normalization, percent-encoding normalization and path segment normalization.

 	 * XXX: Percent-encoding normalization does not escape characters that need to be escaped.

 	 *      (Although that would not be a valid URI in the first place. See validate().)

 	 * See RFC 3986 section 6.2.2.

 	 */

 	URI.prototype.normalize = function() {

 		this.removeDotSegments();

 		if (this.scheme)

 			this.scheme = this.scheme.toLowerCase();

 		if (this.authority)

 			this.authority = this.authority.replace(oAuthorityRegex, fAuthority).

 									replace(oCaseRegex, fCase);

 		if (this.path)

 			this.path = this.path.replace(oCaseRegex, fCase);

 		if (this.query)

 			this.query = this.query.replace(oCaseRegex, fCase);

 		if (this.fragment)

 			this.fragment = this.fragment.replace(oCaseRegex, fCase);

 	};

 	var oCaseRegex = /%[0-9a-z]{2}/gi;

 	var oPercentRegex = /[a-zA-Z0-9\-\._~]/;

 	var oAuthorityRegex = /(.*@)?([^@:]*)(:.*)?/;

 	function fCase(sStr) {

 		var sDec = unescape(sStr);

 		return oPercentRegex.test(sDec) ? sDec : sStr.toUpperCase();

 	}

 	function fAuthority(sStr, p1, p2, p3) {

 		return (p1 || '') + p2.toLowerCase() + (p3 || '');

 	}

 	/**

 	 * Resolve a relative URI (this) against a base URI.

 	 * The base URI must be an absolute URI.

 	 * See RFC 3986 section 5.2

 	 */

 	URI.prototype.resolve = function(oBaseURI) {

 		var oURI = new URI();

 		if (this.scheme) {

 			oURI.scheme = this.scheme;

 			oURI.authority = this.authority;

 			oURI.path = this.path;

 			oURI.query = this.query;

 		} else {

 			oURI.scheme = oBaseURI.scheme;

 			if (this.authority) {

 				oURI.authority = this.authority;

 				oURI.path = this.path;

 				oURI.query = this.query;

 			} else {

 				oURI.authority = oBaseURI.authority;

 				if (this.path == '') {

 					oURI.path = oBaseURI.path;

 					oURI.query = this.query || oBaseURI.query;

 				} else {

 					if (this.path.charAt(0) == '/') {

 						oURI.path = this.path;

 						oURI.removeDotSegments();

 					} else {

 						if (oBaseURI.authority && oBaseURI.path == '') {

 							oURI.path = '/' + this.path;

 						} else {

 							oURI.path = oBaseURI.path.substring(0, oBaseURI.path.lastIndexOf('/') + 1) + this.path;

 						}

 						oURI.removeDotSegments();

 					}

 					oURI.query = this.query;

 				}

 			}

 		}

 		oURI.fragment = this.fragment;

 		return oURI;

 	};

 	/**

 	 * Remove dot segments from path.

 	 * See RFC 3986 section 5.2.4

 	 */

 	URI.prototype.removeDotSegments = function() {

 		var aInput = this.path.split('/'),

 			aOutput = [],

 			sSegment,

 			bAbsPath = aInput[0] == '';

 		if (bAbsPath)

 			aInput.shift();

 		var sFirst = aInput[0] == '' ? aInput.shift() : null;

 		while (aInput.length) {

 			sSegment = aInput.shift();

 			if (sSegment == '..') {

 				aOutput.pop();

 			} else if (sSegment != '.') {

 				aOutput.push(sSegment);

 			}

 		}

 		if (sSegment == '.' || sSegment == '..')

 			aOutput.push('');

 		if (bAbsPath)

 			aOutput.unshift('');

 		this.path = aOutput.join('/');

 	};

 	/**

 	 * Serialises the URI to a string.

 	 */

 	URI.prototype.toString = function() {

 		var sResult = '';

 		if (this.scheme)

 			sResult += this.scheme + ':';

 		if (this.authority)

 			sResult += '//' + this.authority;

 		sResult += this.path;

 		if (this.query)

 			sResult += '?' + this.query;

 		if (this.fragment)

 			sResult += '#' + this.fragment;

 		return sResult;

 	};

 	// exports

 	this.URI = URI;

 });