/*

unbad object library Copyright © 2006-2008 - Sean Claflin

unbad object library is licensed under the Creative Commons Attribution 3.0
United States License - http://creativecommons.org/licenses/by/3.0/us/

*/

ub.json = function() {
	//stringify/parse private vars
	var f = function(n) {
        return n < 10 ? '0' + n : n;
    };
	var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;
	var escapeable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;
	var gap = '';
	var indent = '';
	var meta = {
		'\b': '\\b',
		'\t': '\\t',
		'\n': '\\n',
		'\f': '\\f',
		'\r': '\\r',
		'"' : '\\"',
		'\\': '\\\\'
	}
	var rep = '';
	//async request private vars
	var reqNum = 10;
	var getAsyncHandler = function() {
		return (typeof(XMLHttpRequest) == "undefined") ?
			function() {
				try { new ActiveXObject("Msxml2.XMLHTTP.6.0") } catch(e) {}
				try { new ActiveXObject("Msxml2.XMLHTTP.3.0") } catch(e) {}
				try { new ActiveXObject("Msxml2.XMLHTTP") } catch(e) {}
				try { new ActiveXObject("Microsoft.XMLHTTP") } catch(e) {}
				throw new Error( "This browser does not support XMLHttpRequest." )
			}() :
			new XMLHttpRequest();
	};
	var prepReq = function(params, callback, requestType, uri, scope) {
		var req = ++reqNum;
		var data = '';
		if(requestType == 'GET') {
			uri += ((uri.indexOf('?') == -1) ? '?' : '&') + 'jsonreq='+ encodeURIComponent(json.stringify(params));
			uri += '&jrnd='+ new Date().getTime();
		}
		else if(requestType == 'POST') {
			data = 'jsonreq='+ encodeURIComponent(json.stringify(params)).replace(/\+/g, '%2B');
			data += '&jrnd='+ new Date().getTime();
		}
		else throw new Error("Invalid requestType.  Must be GET or POST.");
		var handler = getAsyncHandler();
		handler.open(requestType, uri, true);
		if(requestType == 'POST') {
			handler.setRequestHeader("Method", "POST " + uri + " HTTP/1.1");
			handler.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
		}
		handler.onreadystatechange = function() {
			if(handler.readyState != 4) return;
			try {
				var res = json.parse(handler.responseText);
				
			} catch(e) {
				res = { result: 'fail', response: handler.responseText };
			}
			if(typeof(callback) == 'function')
				callback.call(scope, res, req);
			delete handler;
		};
		handler.send(data);
	};
	if (typeof Date.prototype.toJSON !== 'function') {
		Date.prototype.toJSON = function (key) {
			return this.getUTCFullYear()   + '-' +
				 f(this.getUTCMonth() + 1) + '-' +
				 f(this.getUTCDate())      + 'T' +
				 f(this.getUTCHours())     + ':' +
				 f(this.getUTCMinutes())   + ':' +
				 f(this.getUTCSeconds())   + 'Z';
		};
		String.prototype.toJSON =
		Number.prototype.toJSON =
		Boolean.prototype.toJSON = function (key) {
			return this.valueOf();
		};
	}
	var json = {
		quote: function(string) {
			// If the string contains no control characters, no quote characters,
			// and no backslash characters, then we can safely slap some quotes
			// around it. Otherwise we must also replace the offending characters
			// with safe escape sequences.
			escapeable.lastIndex = 0;
			return escapeable.test(string) ?
				'"' + string.replace(escapeable, function (a) {
					var c = meta[a];
					if (typeof c === 'string') {
						return c;
					}
					return '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
				}) + '"' :
				'"' + string + '"';
		},
		str: function(key, holder) {
			// Produce a string from holder[key].
			var i,          // The loop counter.
			k,          // The member key.
			v,          // The member value.
			length,
			mind = gap,
			partial,
			value = holder[key];
			// If the value has a toJSON method, call it to obtain a replacement value.
			if (value && typeof value === 'object' && typeof value.toJSON === 'function') {
				value = value.toJSON(key);
			}
			// If we were called with a replacer function, then call the replacer to
			// obtain a replacement value.
			if (typeof rep === 'function') {
				value = rep.call(holder, key, value);
			}
			// What happens next depends on the value's type.
			switch (typeof value) {
				case 'string':
					return this.quote(value);
				case 'number':
					// JSON numbers must be finite. Encode non-finite numbers as
					// null.
					return isFinite(value) ? String(value) : 'null';
				case 'boolean':
				case 'null':
					// If the value is a boolean or null, convert it to a string.
					// Note: typeof null does not produce 'null'. The case is
					// included here in the remote chance that this gets fixed
					// someday.
					return String(value);
					// If the type is 'object', we might be dealing with an object
					// or an array or null.
				case 'object':
					// Due to a specification blunder in ECMAScript, typeof null is
					// 'object', so watch out for that case.
					if (!value) {
						return 'null';
					}
					// Make an array to hold the partial results of stringifying
					// this object value.
					gap += indent;
					partial = [];
					// If the object has a dontEnum length property, we'll treat it
					// as an array.
					if (typeof value.length === 'number' && !value.propertyIsEnumerable('length')) {
						// The object is an array. Stringify every element. Use null
						// as a placeholder for non-JSON values.
						length = value.length;
						for (i = 0; i < length; i += 1) {
							partial[i] = this.str(i, value) || 'null';
						}
						// Join all of the elements together, separated with commas,
						// and wrap them in brackets.
						v = (partial.length === 0) ?
							'[]' :
							(
								gap ?
									'[\n' + gap + partial.join(',\n' + gap) + '\n' + mind + ']' :
									'[' + partial.join(',') + ']'
							);
						gap = mind;
						return v;
					}
					// If the replacer is an array, use it to select the members to be stringified.
					if (rep && typeof rep === 'object') {
						length = rep.length;
						for (i = 0; i < length; i += 1) {
							k = rep[i];
							if (typeof k === 'string') {
								v = this.str(k, value);
								if (v) {
									partial.push(this.quote(k) + (gap ? ': ' : ':') + v);
								}
							}
						}
					}
					// Otherwise, iterate through all of the keys in the object.
					else {
						for (k in value) {
							if (Object.hasOwnProperty.call(value, k)) {
								v = this.str(k, value);
								if (v) {
									partial.push(this.quote(k) + (gap ? ': ' : ':') + v);
								}
							}
						}
					}
					// Join all of the member texts together, separated with commas,
					// and wrap them in braces.
					v = partial.length === 0 ?
						'{}' :
						(
							gap ?
								'{\n' + gap + partial.join(',\n' + gap) + '\n' + mind + '}' :
								'{' + partial.join(',') + '}'
						);
					gap = mind;
					return v;
			}
		},
		stringify: function(value, replacer, space) {
			// The stringify method takes a value and an optional replacer, and an
			// optional space parameter, and returns a JSON text. The replacer can
			// be a function that can replace values, or an array of strings that
			// will select the keys. A default replacer method can be provided. Use
			// of the space parameter can produce text that is more easily readable.
			var i;
			gap = '';
			indent = '';
			// If the space parameter is a number, make an indent string containing
			// that many spaces.
			if (typeof space === 'number') {
				for (i = 0; i < space; i += 1) {
					indent += ' ';
				}
			// If the space parameter is a string, it will be used as the indent
			// string.
			} else if (typeof space === 'string') {
				indent = space;
			}
			// If there is a replacer, it must be a function or an array. Otherwise,
			// throw an error.
			rep = replacer;
			if (replacer && typeof replacer !== 'function' && (
				typeof replacer !== 'object' ||
				typeof replacer.length !== 'number'
			)) {
				throw new Error('ub.json.stringify');
			}
			// Make a fake root object containing our value under the key of ''.
			// Return the result of stringifying the value.
			return this.str('', {'': value});
		},
		parse: function (text, reviver) {
			// The parse method takes a text and an optional reviver function, and returns
			// a JavaScript value if the text is a valid JSON text.
			var j;
			
			function walk(holder, key) {
				// The walk method is used to recursively walk the resulting structure so
				// that modifications can be made.
				var k, v, value = holder[key];
				if (value && typeof value === 'object') {
					for (k in value) {
						if (Object.hasOwnProperty.call(value, k)) {
							v = walk(value, k);
							if (v !== undefined) {
								value[k] = v;
							} else {
								delete value[k];
							}
						}
					}
				}
				return reviver.call(holder, key, value);
			}
			// Parsing happens in four stages. In the first stage, we replace certain
			// Unicode characters with escape sequences. JavaScript handles many characters
			// incorrectly, either silently deleting them, or treating them as line endings.
			cx.lastIndex = 0;
			if (cx.test(text)) {
				text = text.replace(cx, function (a) {
					return '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
				});
			}
			// In the second stage, we run the text against regular expressions that
			// look for non-JSON patterns. We are especially concerned with '()' and
			// 'new' because they can cause invocation, and '=' because it can cause
			// mutation. But just to be safe, we want to reject all unexpected
			// forms.
			
			// We split the second stage into 4 regexp operations in order to work
			// around crippling inefficiencies in IE's and Safari's regexp engines.
			// First we replace the JSON backslash pairs with '@' (a non-JSON
			// character). Second, we replace all simple value tokens with ']'
			// characters. Third, we delete all open brackets that follow a colon or
			// comma or that begin the text. Finally, we look to see that the
			// remaining characters are only whitespace or ']' or ',' or ':' or '{'
			// or '}'. If that is so, then the text is safe for eval.
			if (
				/^[\],:{}\s]*$/.test(
					text.replace(
						/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g, '@'
					).replace(
						/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']'
					).replace(
						/(?:^|:|,)(?:\s*\[)+/g, ''
					)
				)
			) {
				// In the third stage we use the eval function to compile the text into a
				// JavaScript structure. The '{' operator is subject to a syntactic ambiguity
				// in JavaScript: it can begin a block or an object literal. We wrap the text
				// in parens to eliminate the ambiguity.
				j = eval('(' + text + ')');
				// In the optional fourth stage, we recursively walk the new structure, passing
				// each name/value pair to a reviver function for possible transformation.
				return typeof reviver === 'function' ? walk({'': j}, '') : j;
			}
			// If the text is not JSON parseable, then a SyntaxError is thrown.
			throw new SyntaxError('ub.json.parse');
		},
		async: {
			get: function(rpc, params, callback, uri, scope) {
				params.unshift(rpc);
				prepReq(params, callback, 'GET', (uri) ? uri : window.location.href, (scope) ? scope : this);
			},
			post: function(rpc, params, callback, uri, scope) {
				params.unshift(rpc);
				prepReq(params, callback, 'POST', (uri) ? uri : window.location.href, (scope) ? scope : this);
			}
		},
		jsonp: {
			get: function(rpc, params, callback, uri, scope) {
				throw new Error("JSONP not yet implemented");
			},
			post: function(rpc, params, callback, uri, scope) {
				throw new Error("JSONP not yet implemented");
			}
		}
	}
	return json;
}();