/**
 * Copyright (c) 2006, Yusuke Inuzuka<yuin@inforno.net>(http://inforno.net)
 *
 * License :
 *	 Articstic License 2.0
 *
 * Lyase.View :
 *	 This class is a part of javascript framework "Lyase"(under making...)
 *	 This class requires prototype.js(http://prototype.conio.net/)
 *
 * Description :
 *
 *	 Lyase.View provides simple way to embed javascript codes
 *	 within any plain text.
 *
 * Usage and examples :
 *
 *	 using text
 *	 -------------
 *	 var template = "The value of x is:<%= context.x%>";
 *	 document.write(Lyase.View.render({text:template}, {x : 10}));
 *
 *	 using innerHTML
 *	 -------------
 *	 //in HTML
 *	 <textarea id="template" style="display:none">
 *		 The value of x is:<%= context.x%>
 *	 </textarea>
 *	 //code
 *	 document.write(Lyase.View.render({element:"template"}, {x : 10}));
 *
 *	 using a template file
 *	 -------------
 *	 //in /template.jhtml
 *	 The value of x is:<%= context.x%>
 *	 //code
 *	 document.write(Lyase.View.render({file:"/template.jhtml"}, {x : 10}));
 *
 *	 Of course, you can embed more complex codes.
 *	 //in HTML, with prototype.js
 *	 <textarea id="template" style="display:none">
 *		 <% context.list.each(function(pair){%>
 *					The value of <%= pair.name %> is: <%= pair.value%>
 *		 <% }) %>
 *	 </textarea>
 *	 //code
 *	 document.write(Lyase.View.render({element:"template"},
 *		 {list :[{name : "x", value : 10}, {name : "y", value : 20}]}));
 *
 *
 * Recognized Tags :
 *
 *	 <% javascript code %>
 *	 <%= javascript expression %>
 *	 <%\* comment *\%>(\ is meaning of /)
 */
var Lyase = {};
Lyase.View = {
	_cache : {},
	parse : function(template, id) {
		var self = Lyase.View,parsed = ["var __out=[],render = Lyase.View.render;"]
		var tokens = template.split("<%");
		for(var i = 0, l = tokens.length; i<l; i++) {
			var token = tokens[i];
			if(token.indexOf("%>") == -1){
				parsed.push(self._string(token));
				continue;
			}
			var parts = token.split("%>");
			parsed.push(self[(parts[0].charAt(0) == "=")?"_value":"_code"](parts[0]));
			parsed.push(self._string(parts[1]));
		}
		parsed.push("return __out.join('');");
		var templateFunc = new Function("context", parsed.join(""));
		if(id) self._cache[id] = templateFunc;
		return templateFunc;
	},

	render : function(options, values) {
		var self = Lyase.View, template, id;
		if(options.text) return self.parse(options.text, null)(values);
		if(options.element){
			var element = $(options.element);
		}
		id = (options.file) ? options.file : element.id;
		if(self._cache[id]){
			return self._cache[id](values);
		}
		if(options.element) {
			template = self._elementTemplate(element);
		}else {
			//template = (new Ajax.Request(options.file,{asynchronous : false})).transport.responseText;
			//template = (new Ajax.Request(options.file,{asynchronous : false, method:'get'})).transport.responseText;
			template = self._get( options.file );
		}
		return self.parse(template, id)(values);
	},

	_elementTemplate : function(element) {
		var template = element.innerHTML;
		if(element.tagName.toLowerCase() != "textarea") {
			// modified by m.o. undepend on prototype.js
			template = template.split("<!--[CDATA[")[1].split("]]-->")[0];
		}else if(template.indexOf("&lt;") != -1) {
			// template = template.unescapeHTML();
			// modified by Masakazu O. to make undepent on prototype.js
			// textarea unsupported, use div
		}
		return template.replace(/\n|\r/g, "");
	},

	_string : function(string) {
		return ["__out.push('",string.replace(/\n|\r/g,"").replace(/'/g, "\\'"),"');"].join("");
	},

	_value	: function(string) {
		return ["__out.push(",string.replace(/\n|\r/g,"").substring(1),");"].join("");
	},

	_code 	: function(string) {
		string = string.replace(/\n|\r/g,"");
		if(string.charAt(string.length-1) != ";") string += ";";
		return string;
	},

	// Masakazu O. added below
	_get : function( url ){
		var req;
		if (window.XMLHttpRequest) {
			req = new XMLHttpRequest();
		} else if (window.ActiveXObject) {
			req = new ActiveXObject("Microsoft.XMLHTTP");
		}
		if (req) {
			req.open("GET", url, false);
			req.send("");
			return req.responseText;
		}else{
			return '';
		}
	}
}