/**
 * Subsys_JsHttpRequest_Js: JavaScript DHTML data loader.
 * (C) 2005 Dmitry Koterov, http://forum.dklab.ru/users/DmitryKoterov/
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * See http://www.gnu.org/copyleft/lesser.html
 *
 * Do not remove this comment if you want to use script!
 * Не удаляйте данный комментарий, если вы хотите использовать скрипт!
 *
 * This library tries to use XMLHttpRequest (if available), and on 
 * failure - use dynamically created <script> elements. Backend code
 * is the same for both cases.
 *
 * @author Dmitry Koterov 
 * @version 3.20
 */

function Subsys_JsHttpRequest_Js() { this._construct() }
(function() { // to create local-scope variables
var COUNT       = 0;
var PENDING     = {};
var CACHE       = {};

// Called by server script on data load.
Subsys_JsHttpRequest_Js.dataReady = function(id, text, js) {
var undef;
var th = PENDING[id];
delete PENDING[id];
if (th) {
delete th._xmlReq;
if (th.caching) CACHE[th.hash] = [text, js];
th._dataReady(text, js);
} else if (typeof(th) != typeof(undef)) {
alert("ScriptLoader: unknown pending id: "+id);
}
}

Subsys_JsHttpRequest_Js.prototype = {
// Standard properties.
onreadystatechange: null,
readyState:         0,
responseText:       null,
responseXML:        null,
status:             200,
statusText:         "OK",

// Additional properties.
session_name:       "PHPSESSID",  // set to SID cookie or GET parameter name
responseJS:         null,         // JavaScript response array/hash
caching:            false,        // need to use caching?

// Internals.
_span:              null,
_id:                null,
_xmlReq:            null,
_openArg:           null,
_reqHeaders:        null,

abort: function() {
if (this._xmlReq) return this._xmlReq.abort();
if (this._span) {
this.readyState = 0;
if (this.onreadystatechange) this.onreadystatechange();
this._cleanupScript();
}
},

open: function(method, url, asyncFlag, username, password) {
this._openArg = {
'method':    method,
'url':       url,
'asyncFlag': asyncFlag,
'username':  username,
'password':  password
};
this._id = null;
this._xmlReq = null;
this._reqHeaders = [];
return true;
},

send: function(content) {
var id = COUNT++;

// Build QUERY_STRING from query hash.
var query = this._hash2query(content);

// Append SID to original URL now.
var url = this._openArg.url;
var sid = this._getSid();
if (sid) url += (url.indexOf('?')>=0? '&' : '?') + this.session_name + "=" + escape(sid);

// Solve hash BEFORE appending ID.
var hash = this.hash = url + '?' + query;
if (this.caching && CACHE[hash]) {
var c = CACHE[hash];
this._dataReady(c[0], c[1]);
return false;
}

// Try to use XMLHttpRequest.
this._xmlReq = this._obtainXmlReq(id, url);

// Pass data in URL (GET, HEAD etc.) or in request body (POST)?
var hasSetHeader = this._xmlReq && (window.ActiveXObject || this._xmlReq.setRequestHeader); 
var href, body;
if (this._xmlReq && hasSetHeader && (""+this._openArg.method).toUpperCase() == "POST") {
// Use POST method. Pass query in request body.
// Opera 8.01 does not support setRequestHeader, so no POST method.
this._openArg.method = "POST";
href = url;
body = query;
} else {
this._openArg.method = "GET";
href = url + (url.indexOf('?')>=0? '&' : '?') + query;
body = null;
}

// Append ID: a=aaa&b=bbb&<id>
href = href + (href.indexOf('?')>=0? '&' : '?') + id;

// Save loading script.
PENDING[id] = this;

if (this._xmlReq) {
// Open request now & send it.
// In XMLHttpRequest mode request URL MUST be ended with "&".
var a = this._openArg;
this._xmlReq.open(a.method, href+"&", a.asyncFlag, a.username, a.password);
if (hasSetHeader) {
// Pass pending headers.
for (var i=0; i<this._reqHeaders.length; i++)
this._xmlReq.setRequestHeader(this._reqHeaders[i][0], this._reqHeaders[i][1]);
// Set non-default Content-type. We cannot use 
// "application/x-www-form-urlencoded" here, because 
// in PHP variable HTTP_RAW_POST_DATA is accessible only when 
// enctype is not default (e.g., "application/octet-stream" 
// is a good start). We parse POST data manually in backend 
// library code.
this._xmlReq.setRequestHeader('Content-Type', 'application/octet-stream');
}
// Send the request.
return this._xmlReq.send(body);
} else {
// Create <script> element and run it.
this._obtainScript(id, href);
return true;
}
},

getAllResponseHeaders: function() {
if (this._xmlReq) return this._xmlReq.getAllResponseHeaders();
return '';
},

getResponseHeader: function(label) {
if (this._xmlReq) return this._xmlReq.getResponseHeader(label);
return '';
},

setRequestHeader: function(label, value) {
// Collect headers.
this._reqHeaders[this._reqHeaders.length] = [label, value];
},


//
// Internal functions.
//

// Constructor.
_construct: function() {},

// Do all work when data is ready.
_dataReady: function(text, js) { with (this) {
if (text !== null || js !== null) {
readyState = 4;
responseText = responseXML = text;
responseJS = js;
} else {
readyState = 0;
responseText = responseXML = responseJS = null;
}
if (onreadystatechange) onreadystatechange();
_cleanupScript();
}},

// Create new XMLHttpRequest object.
_obtainXmlReq: function(id, url) {
// If url.domain specified, cannot use XMLHttpRequest!
if (url.match(new RegExp('^[a-z]+://', 'i'))) return null;

// Try to use built-in loaders.
var req = null;
if (window.XMLHttpRequest) {
try { req = new XMLHttpRequest() } catch(e) {}
} else if (window.ActiveXObject) {
try { req = new ActiveXObject("Microsoft.XMLHTTP") } catch(e) {}
if (!req) try { req = new ActiveXObject("Msxml2.XMLHTTP") } catch (e) {}
}
if (req) {
var th = this;
req.onreadystatechange = function() { 
if (req.readyState == 4) {
// Call associated dataReady().
//alert ('responcetext:' + req.responseText);
	try {eval(req.responseText);
	}
	catch (eee){
			alert ('err: ' + req.responseText);
	}
} else {
th.readyState = req.readyState;
if (th.onreadystatechange) th.onreadystatechange() 
}
};
this._id = id;
}
return req;
},

// Create new script element and start loading.
_obtainScript: function(id, href) { with (document) {
var span = null;
// Oh shit! Damned stupid fucked Opera 7.23 does not allow to create SCRIPT 
// element over createElement (in HEAD or BODY section or in nested SPAN - 
// no matter): it is created deadly, and does not respons on href assignment.
// So - always create SPAN.
span = body.appendChild(createElement("SPAN"));
span.style.display = 'none';
span.innerHTML = 'Text for stupid IE.<s'+'cript></' + 'script>';
setTimeout(function() {
var s = span.getElementsByTagName("script")[0];
s.language = "JavaScript";
if (s.setAttribute) s.setAttribute('src', href); else s.src = href;
}, 10);
this._id = id;
this._span = span;
}},

// Remove last used script element (clean memory).
_cleanupScript: function() {
var span = this._span;
if (span) {
this._span = null;
setTimeout(function() {
// without setTimeout - crash in IE 5.0!
span.parentNode.removeChild(span);
}, 50);
}
return false;
},

// Convert hash to QUERY_STRING.
_hash2query: function(content) {
var query = [];
if (content instanceof Object) {
// TODO: build more nested objects in PHP-style.
for (var k in content) {
query[query.length] = escape(k) + "=" + escape(content[k]);
}
} else {
query = [content];
}
return query.join('&');
},

// Return value of SID based on QUERY_STRING or cookie
// (PHP compatible sessions).
_getSid: function() {
var m = document.location.search.match(new RegExp('[&?]'+this.session_name+'=([^&?]*)'));
var sid = null;
if (m) {
sid = m[1];
} else {
var m = document.cookie.match(new RegExp(s='(;|^)\\s*'+this.session_name+'=([^;]*)'));
if (m) sid = m[2];
}
return sid;
}
}
})();