function cpaint() {

  this.version = '2.0.3';
  

  var config                      = new Array();
  config['debugging']             = -1;
  config['proxy_url']             = '';
  config['transfer_mode']         = 'GET';
  config['async']                 = true;
  config['response_type']         = 'OBJECT';
  config['persistent_connection'] = false;
  config['use_cpaint_api']        = true;

  var stack_count = 0;


  this.capable = test_ajax_capability();
  

  this.set_debug = function() {
    
    if (typeof arguments[0] == 'boolean') {
      if (arguments[0] === true) {
        config['debugging'] = 1;

      } else {
        config['debugging'] = 0;
      }
      
    } else if (typeof arguments[0] == 'number') {
      config['debugging'] = Math.round(arguments[0]);
    }
  }


  this.set_proxy_url = function() {
    
    if (typeof arguments[0] == 'string') {

      config['proxy_url'] = arguments[0];
    }
  }


  this.set_transfer_mode = function() {
    
    if (arguments[0].toUpperCase() == 'GET'
      || arguments[0].toUpperCase() == 'POST') {

      config['transfer_mode'] = arguments[0].toUpperCase();
    }
  }


  this.set_async = function() {
    
    if (typeof arguments[0] == 'boolean') {
      config['async'] = arguments[0];
    }
  }


  this.set_response_type = function() {
    
    if (arguments[0].toUpperCase() == 'TEXT'
      || arguments[0].toUpperCase() == 'XML'
      || arguments[0].toUpperCase() == 'OBJECT'
      || arguments[0].toUpperCase() == 'E4X'
      || arguments[0].toUpperCase() == 'JSON') {

      config['response_type'] = arguments[0].toUpperCase();
    }
  }


  this.set_persistent_connection = function() {
    
    if (typeof arguments[0] == 'boolean') {
      config['persistent_connection'] = arguments[0];
    }
  }
  
  

  this.set_use_cpaint_api = function() {
    if (typeof arguments[0] == 'boolean') {
      config['use_cpaint_api'] = arguments[0];
    }
  }
  

  function test_ajax_capability() {
    var cpc = new cpaint_call(0, config, this.version);
    return cpc.test_ajax_capability();
  }


  this.call = function() {
    var use_stack = -1;
    
    if (config['persistent_connection'] == true
      && __cpaint_stack[0] != null) {

      switch (__cpaint_stack[0].get_http_state()) {
        case -1:
          // no XMLHttpObject object has already been instanciated
          // create new object and configure it
          use_stack = 0;
          debug('no XMLHttpObject object to re-use for persistence, creating new one later', 2);
          break;
          
        case 4:
          // object is ready for a new request, no need to do anything
          use_stack = 0
          debug('re-using the persistent connection', 2);
          break;
          
        default:
          // connection is currently in use, don't do anything
          debug('the persistent connection is in use - skipping this request', 2);
      }
      
    } else if (config['persistent_connection'] == true) {
      // persistent connection is active, but no object has been instanciated
      use_stack = 0;
      __cpaint_stack[use_stack] = new cpaint_call(use_stack, config, this.version);
      debug('no cpaint_call object available for re-use, created new one', 2);
    
    } else {
      // no connection persistance
      use_stack = stack_count;
      __cpaint_stack[use_stack] = new cpaint_call(use_stack, config, this.version);
      debug('no cpaint_call object created new one', 2);
    }

    // configure cpaint_call if allowed to
    if (use_stack != -1) {
      __cpaint_stack[use_stack].set_client_callback(arguments[2]);
      
      // distribute according to proxy use
      if (config['proxy_url'] != '') {
        __cpaint_stack[use_stack].call_proxy(arguments);
      
      } else {
        __cpaint_stack[use_stack].call_direct(arguments);
      }

      // increase stack counter
      stack_count++;
      debug('stack size: ' + __cpaint_stack.length, 2);
    }
  }


  var debug  = function(message, debug_level) {
    var prefix = '[CPAINT Debug] ';
    
    if (debug_level < 1) {
      prefix = '[CPAINT Error] ';
    }
    
    if (config['debugging'] >= debug_level) {
      alert(prefix + message);
    }
  }
}


var __cpaint_stack = new Array();


var __cpaint_transformer = new cpaint_transformer();


function cpaint_call() {

  var version = arguments[2];
  

  var config                      = new Array();
  config['debugging']             = arguments[1]['debugging'];
  config['proxy_url']             = arguments[1]['proxy_url'];
  config['transfer_mode']         = arguments[1]['transfer_mode'];
  config['async']                 = arguments[1]['async'];
  config['response_type']         = arguments[1]['response_type'];
  config['persistent_connection'] = arguments[1]['persistent_connection'];
  config['use_cpaint_api']        = arguments[1]['use_cpaint_api'];


  var httpobj    = false;


  var client_callback;


  var stack_id = arguments[0];
  

  this.set_client_callback = function() {
    
    if (typeof arguments[0] == 'function') {
      client_callback = arguments[0];
    }
  }


  this.get_http_state = function() {
    var return_value = -1;
    
    if (typeof httpobj == 'object') {
      return_value = httpobj.readyState;
    }
    
    return return_value;
  }
  

  this.call_direct = function(call_arguments) {
    var url             = call_arguments[0];
    var remote_method   = call_arguments[1];
    var querystring     = '';
    var i               = 0;
    
    // correct link to self
    if (url == 'SELF') {
      url = document.location.href;
    }
  
    if (config['use_cpaint_api'] == true) {
      // backend uses cpaint api
      // pass parameters to remote method
      for (i = 3; i < call_arguments.length; i++) {

        if ((typeof call_arguments[i] == 'string'
              && call_arguments[i] != ''
              && call_arguments[i].search(/^\s+$/g) == -1)
          && !isNaN(call_arguments[i])
          && isFinite(call_arguments[i])) {
          // numerical value, convert it first
          querystring += '&cpaint_argument[]=' + encodeURIComponent(JSON.stringify(Number(call_arguments[i])));
        
        } else {
          querystring += '&cpaint_argument[]=' + encodeURIComponent(JSON.stringify(call_arguments[i]));
        }
      }
    
      // add response type to querystring
      querystring += '&cpaint_response_type=' + config['response_type'];
    
      // build header
      if (config['transfer_mode'] == 'GET') {
				
        if(url.indexOf('?') != -1) {
					url = url + '&cpaint_function=' + remote_method +	querystring;
				
        } else {
					url = url + '?cpaint_function=' + remote_method +	querystring; 
				}
      
      } else {
        querystring = 'cpaint_function=' + remote_method + querystring;
      }
      
    } else {
      // backend does not use cpaint api
      // pass parameters to remote method
      for (i = 3; i < call_arguments.length; i++) {
        
        if (i == 3) {
          querystring += encodeURIComponent(call_arguments[i]);
        
        } else {
          querystring += '&' + encodeURIComponent(call_arguments[i]);
        }
      }
    
      // build header
      if (config['transfer_mode'] == 'GET') {
        url = url + querystring;
      } 
    }
  
    // open connection 
    get_connection_object();

    // open connection to remote target
    debug('opening connection to "' + url + '"', 1);
    httpobj.open(config['transfer_mode'], url, config['async']);

    // send "urlencoded" header if necessary (if POST)
    if (config['transfer_mode'] == 'POST') {

      try {
        httpobj.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

      } catch (cp_err) {
        debug('POST cannot be completed due to incompatible browser.  Use GET as your request method.', 0);
      }
    }

    // make ourselves known
    httpobj.setRequestHeader('X-Powered-By', 'CPAINT v' + version + ' :: http://sf.net/projects/cpaint');

    // callback handling for asynchronous calls
    httpobj.onreadystatechange = callback;

    // send content
    if (config['transfer_mode'] == 'GET') {
      httpobj.send(null);

    } else {
      debug('sending query: ' + querystring, 1);
      httpobj.send(querystring);
    }

    if (config['async'] == true) {
      // manual callback handling for synchronized calls
      callback();
    }
  }
    

  this.call_proxy = function(call_arguments) {
    var proxyscript     = config['proxy_url'];
    var url             = call_arguments[0];
    var remote_method   = call_arguments[1];
    var querystring     = '';
    var i               = 0;
    
    var querystring_argument_prefix = 'cpaint_argument[]=';

    // pass parameters to remote method
    if (config['use_cpaint_api'] == false) {
      // when not talking to a CPAINT backend, don't prefix arguments
      querystring_argument_prefix = '';
    }

    for (i = 3; i < call_arguments.length; i++) {

      if (config['use_cpaint_api'] == true) {
      
        if ((typeof call_arguments[i] == 'string'
              && call_arguments[i] != ''
              && call_arguments[i].search(/^\s+$/g) == -1)
          && !isNaN(call_arguments[i])
          && isFinite(call_arguments[i])) {
          // numerical value, convert it first
          querystring += encodeURIComponent(querystring_argument_prefix + JSON.stringify(Number(call_arguments[i])) + '&');

        } else {
          querystring += encodeURIComponent(querystring_argument_prefix + JSON.stringify(call_arguments[i]) + '&');
        }
        
      } else {
        // no CPAINT in the backend
        querystring += encodeURIComponent(querystring_argument_prefix + call_arguments[i] + '&');
      }
    }

    if (config['use_cpaint_api'] == true) {
      // add remote function name to querystring
      querystring += encodeURIComponent('&cpaint_function=' + remote_method);
  
      // add response type to querystring
      querystring += encodeURIComponent('&cpaint_responsetype=' + config['response_type']);
    }
    
    // build header
    if (config['transfer_mode'] == 'GET') {
      proxyscript += '?cpaint_remote_url=' + encodeURIComponent(url) 
        + '&cpaint_remote_query=' + querystring
        + '&cpaint_remote_method=' + config['transfer_mode'] 
        + '&cpaint_response_type=' + config['response_type'];

    } else {
      querystring = 'cpaint_remote_url=' + encodeURIComponent(url)
        + '&cpaint_remote_query=' + querystring
        + '&cpaint_remote_method=' + config['transfer_mode'] 
        + '&cpaint_response_type=' + config['response_type'];
    }

    // open connection
    get_connection_object();

    // open connection to remote target
    debug('opening connection to proxy "' + proxyscript + '"', 1);
    httpobj.open(config['transfer_mode'], proxyscript, config['async']);

    // send "urlencoded" header if necessary (if POST)
    if (config['transfer_mode'] == 'POST') {

      try {
        httpobj.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

      } catch (cp_err) {
        debug('POST cannot be completed due to incompatible browser.  Use GET as your request method.', 0);
      }
    }

    httpobj.setRequestHeader('X-Powered-By', 'CPAINT v' + version);

    // callback handling for asynchronous calls
    httpobj.onreadystatechange = callback;

    // send content
    if (config['transfer_mode'] == 'GET') {
      httpobj.send(null);

    } else {
      debug('sending query: ' + querystring, 1);
      httpobj.send(querystring);
    }

    if (config['async'] == false) {
      // manual callback handling for synchronized calls
      callback();
    }
  }

  this.test_ajax_capability = function() {
    return get_connection_object();
  }
  

  var get_connection_object = function() {
    var return_value    = false;
    var new_connection  = false;

    // open new connection only if necessary
    if (config['persistent_connection'] == false) {
      // no persistance, create a new object every time
      debug('Using new connection object', 1);
      new_connection = true;

    } else {
      // persistent connection object, only open one if no object exists
      debug('Using shared connection object.', 1);

      if (typeof httpobj != 'object') {
        debug('Getting new persistent connection object.', 1);
        new_connection = true;
      }
    }

    if (new_connection == true) {
		
	 try {
        httpobj = new XMLHttpRequest();
      } catch (e1) {

		  try {
			httpobj = new ActiveXObject('Msxml2.XMLHTTP');
	  
		  } catch (e) {
			
			try {  
			  httpobj = new ActiveXObject('Microsoft.XMLHTTP');
 
			} catch (oc) {
			  httpobj = null;
			} 
		 }
	  }
     
  
      if (!httpobj) {
        debug('Could not create connection object', 0);
      
      } else {
        return_value = true;
      }
    }

    if (httpobj.readyState != 4) {
      httpobj.abort();
    }

    return return_value;
  }


  var callback = function() {
    var response = null;

    if (httpobj.readyState == 4
      && httpobj.status == 200) {
      
      debug(httpobj.responseText, 1);
      debug('using response type ' + config['response_type'], 2);
      
      // fetch correct response
      switch (config['response_type']) {
        case 'XML':
          debug(httpobj.responseXML, 2);
          response = __cpaint_transformer.xml_conversion(httpobj.responseXML);
          break;
          
        case 'OBJECT':
          response = __cpaint_transformer.object_conversion(httpobj.responseXML);
          break;
        
        case 'TEXT':
          response = __cpaint_transformer.text_conversion(httpobj.responseText);
          break;
          
        case 'E4X':
          response = __cpaint_transformer.e4x_conversion(httpobj.responseText);
          break;
          
        case 'JSON':
          response = __cpaint_transformer.json_conversion(httpobj.responseText);
          break;
          
        default:
          debug('invalid response type \'' + response_type + '\'', 0);
      }
      
      // call client side callback
      if (response != null 
        && typeof client_callback == 'function') {
        client_callback(response, httpobj.responseText);
      }
      
      // remove ourselves from the stack
      remove_from_stack();
    
    } else if (httpobj.readyState == 4
      && httpobj.status != 200) {
      // HTTP error of some kind
      debug('invalid HTTP response code \'' + Number(httpobj.status) + '\'', 0);
    }
  }


  var remove_from_stack = function() {
    // remove only if everything is okay and we're not configured as persistent connection
    if (typeof stack_id == 'number'
      && __cpaint_stack[stack_id]
      && config['persistent_connection'] == false) {
      
      __cpaint_stack[stack_id] = null;
    }
  }


  var debug  = function(message, debug_level) {
    var prefix = '[CPAINT Debug] ';
    
    if (config['debugging'] < 1) {
      prefix = '[CPAINT Error] ';
    }
    
    if (config['debugging'] >= debug_level) {
      alert(prefix + message);
    }
  }
}


function cpaint_transformer() {


  this.object_conversion = function(xml_document) {
    var return_value  = new cpaint_result_object();
    var i             = 0;
    var firstNodeName = '';
    
    if (typeof xml_document == 'object'
      && xml_document != null) {

      // find the first element node - for MSIE the <?xml?> node is the very first...
      for (i = 0; i < xml_document.childNodes.length; i++) {

        if (xml_document.childNodes[i].nodeType == 1) {
          firstNodeName = xml_document.childNodes[i].nodeName;
          break;
        }
      }
      
      var ajax_response = xml_document.getElementsByTagName(firstNodeName);

      return_value[firstNodeName] = new Array();
    
      for (i = 0; i < ajax_response.length; i++) {
        var tmp_node = create_object_structure(ajax_response[i]);
        tmp_node.id  = ajax_response[i].getAttribute('id')
        return_value[firstNodeName].push(tmp_node);
      }

    } else {
      debug('received invalid XML response', 0);
    }

    return return_value;
  }


  this.xml_conversion = function(xml_document) {
    return xml_document;
  }
  

  this.text_conversion = function(text) {
    return decode(text);
  }
  
  this.e4x_conversion = function(text) {
    // remove <?xml ?>tag
    text = text.replace(/^\<\?xml[^>]+\>/, '');
    return new XML(text);
  }
  

  this.json_conversion = function(text) {
    return JSON.parse(text);
  }
  

  var create_object_structure = function(stream) {
    var return_value = new cpaint_result_object();
    var node_name = '';
    var i         = 0;
    var attrib    = 0;
    
    if (stream.hasChildNodes() == true) {
      for (i = 0; i < stream.childNodes.length; i++) {
  
        node_name = stream.childNodes[i].nodeName;
        node_name = node_name.replace(/[^a-zA-Z0-9_]*/g, '');
        
        // reset / create subnode
        if (typeof return_value[node_name] != 'object') {
          return_value[node_name] = new Array();
        }
        
        if (stream.childNodes[i].nodeType == 1) {
          var tmp_node  = create_object_structure(stream.childNodes[i]);

          for (attrib = 0; attrib < stream.childNodes[i].attributes.length; attrib++) {
            tmp_node.set_attribute(stream.childNodes[i].attributes[attrib].nodeName, stream.childNodes[i].attributes[attrib].nodeValue);
          }
          
          return_value[node_name].push(tmp_node);
        
        } else if (stream.childNodes[i].nodeType == 3) {
          return_value.data  = decode(String(stream.firstChild.data));
        }
      }
    }
    
    return return_value;
  }


  var decode = function(rawtext) {
    var plaintext = ''; 
    var i         = 0; 
    var c1        = 0;
    var c2        = 0;
    var c3        = 0;
    var u         = 0;
    var t         = 0;

    // remove special JavaScript encoded non-printable characters
    while (i < rawtext.length) {
      if (rawtext.charAt(i) == '\\'
        && rawtext.charAt(i + 1) == 'u') {
        
        u = 0;
        
        for (j = 2; j < 6; j += 1) {
          t = parseInt(rawtext.charAt(i + j), 16);
          
          if (!isFinite(t)) {
            break;
          }
          u = u * 16 + t;
        }

        plaintext += String.fromCharCode(u);
        i       += 6;
      
      } else {
        plaintext += rawtext.charAt(i);
        i++;
      }
    }

    // convert numeric data to number type
    if (plaintext != ''
      && plaintext.search(/^\s+$/g) == -1
      && !isNaN(plaintext) 
      && isFinite(plaintext)) {
      
      plaintext = Number(plaintext);
    }
  
    return plaintext;
  }
}


function cpaint_result_object() {
  this.id           = 0;
  this.data         = '';
  var __attributes  = new Array();
  

  this.find_item_by_id = function() {
    var return_value  = null;
    var type    = arguments[0];
    var id      = arguments[1];
    var i       = 0;
    
    if (this[type]) {

      for (i = 0; i < this[type].length; i++) {

        if (this[type][i].get_attribute('id') == id) {
          return_value = this[type][i];
          break;
        }
      }
    }

    return return_value;
  }
  

  this.get_attribute = function() {
    var return_value  = null;
    var id            = arguments[0];
    
    if (typeof __attributes[id] != 'undefined') {
      return_value = __attributes[id];
    }
    
    return return_value;
  }
  

  this.set_attribute = function() {
    __attributes[arguments[0]] = arguments[1];
  }
}



Array.prototype.______array = '______array';

var JSON = {
  org: 'http://www.JSON.org',
  copyright: '(c)2005 JSON.org',
  license: 'http://www.crockford.com/JSON/license.html',

  stringify: function (arg) {
    var c, i, l, s = '', v;
    var numeric = true;
    
    switch (typeof arg) {
    case 'object':
      if (arg) {
        if (arg.______array == '______array') {
          // do a test whether all array keys are numeric
          for (i in arg) {
            if (i != '______array'
              && (isNaN(i) 
                || !isFinite(i))) {
              numeric = false;
              break;
            }
          }
          
          if (numeric == true) {
            for (i = 0; i < arg.length; ++i) {
              if (typeof arg[i] != 'undefined') {
                v = this.stringify(arg[i]);
                if (s) {
                  s += ',';
                }
                s += v;
              } else {
                s += ',null';
              }
            }
            return '[' + s + ']';
          } else {
            for (i in arg) {
              if (i != '______array') {
                v = arg[i];
                if (typeof v != 'undefined' && typeof v != 'function') {
                  v = this.stringify(v);
                  if (s) {
                    s += ',';
                  }
                  s += this.stringify(i) + ':' + v;
                }
              }
            }
            // return as object
            return '{' + s + '}';
          }
        } else if (typeof arg.toString != 'undefined') {
          for (i in arg) {
            v = arg[i];
            if (typeof v != 'undefined' && typeof v != 'function') {
              v = this.stringify(v);
              if (s) {
                s += ',';
              }
              s += this.stringify(i) + ':' + v;
            }
          }
          return '{' + s + '}';
        }
      }
      return 'null';
    case 'number':
      return isFinite(arg) ? String(arg) : 'null';
    case 'string':
      l = arg.length;
      s = '"';
      for (i = 0; i < l; i += 1) {
        c = arg.charAt(i);
        if (c >= ' ') {
          if (c == '\\' || c == '"') {
            s += '\\';
          }
          s += c;
        } else {
          switch (c) {
            case '\b':
              s += '\\b';
              break;
            case '\f':
              s += '\\f';
              break;
            case '\n':
              s += '\\n';
              break;
            case '\r':
              s += '\\r';
              break;
            case '\t':
              s += '\\t';
              break;
            default:
              c = c.charCodeAt();
              s += '\\u00' + Math.floor(c / 16).toString(16) +
                (c % 16).toString(16);
          }
        }
      }
      return s + '"';
    case 'boolean':
      return String(arg);
    default:
      return 'null';
    }
  },
  parse: function (text) {
    var at = 0;
    var ch = ' ';

    function error(m) {
      throw {
        name: 'JSONError',
        message: m,
        at: at - 1,
        text: text
      };
    }

    function next() {
      ch = text.charAt(at);
      at += 1;
      return ch;
    }

    function white() {
      while (ch != '' && ch <= ' ') {
        next();
      }
    }

    function str() {
      var i, s = '', t, u;

      if (ch == '"') {
outer:      while (next()) {
          if (ch == '"') {
            next();
            return s;
          } else if (ch == '\\') {
            switch (next()) {
            case 'b':
              s += '\b';
              break;
            case 'f':
              s += '\f';
              break;
            case 'n':
              s += '\n';
              break;
            case 'r':
              s += '\r';
              break;
            case 't':
              s += '\t';
              break;
            case 'u':
              u = 0;
              for (i = 0; i < 4; i += 1) {
                t = parseInt(next(), 16);
                if (!isFinite(t)) {
                  break outer;
                }
                u = u * 16 + t;
              }
              s += String.fromCharCode(u);
              break;
            default:
              s += ch;
            }
          } else {
            s += ch;
          }
        }
      }
      error("Bad string");
    }

    function arr() {
      var a = [];

      if (ch == '[') {
        next();
        white();
        if (ch == ']') {
          next();
          return a;
        }
        while (ch) {
          a.push(val());
          white();
          if (ch == ']') {
            next();
            return a;
          } else if (ch != ',') {
            break;
          }
          next();
          white();
        }
      }
      error("Bad array");
    }

    function obj() {
      var k, o = {};

      if (ch == '{') {
        next();
        white();
        if (ch == '}') {
          next();
          return o;
        }
        while (ch) {
          k = str();
          white();
          if (ch != ':') {
            break;
          }
          next();
          o[k] = val();
          white();
          if (ch == '}') {
            next();
            return o;
          } else if (ch != ',') {
            break;
          }
          next();
          white();
        }
      }
      error("Bad object");
    }

    function assoc() {
      var k, a = [];

      if (ch == '<') {
        next();
        white();
        if (ch == '>') {
          next();
          return a;
        }
        while (ch) {
          k = str();
          white();
          if (ch != ':') {
            break;
          }
          next();
          a[k] = val();
          white();
          if (ch == '>') {
            next();
            return a;
          } else if (ch != ',') {
            break;
          }
          next();
          white();
        }
      }
      error("Bad associative array");
    }

    function num() {
      var n = '', v;
      if (ch == '-') {
        n = '-';
        next();
      }
      while (ch >= '0' && ch <= '9') {
        n += ch;
        next();
      }
      if (ch == '.') {
        n += '.';
        while (next() && ch >= '0' && ch <= '9') {
          n += ch;
        }
      }
      if (ch == 'e' || ch == 'E') {
        n += 'e';
        next();
        if (ch == '-' || ch == '+') {
          n += ch;
          next();
        }
        while (ch >= '0' && ch <= '9') {
          n += ch;
          next();
        }
      }
      v = +n;
      if (!isFinite(v)) {
        error("Bad number");
      } else {
        return v;
      }
    }

    function word() {
      switch (ch) {
        case 't':
          if (next() == 'r' && next() == 'u' && next() == 'e') {
            next();
            return true;
          }
          break;
        case 'f':
          if (next() == 'a' && next() == 'l' && next() == 's' &&
              next() == 'e') {
            next();
            return false;
          }
          break;
        case 'n':
          if (next() == 'u' && next() == 'l' && next() == 'l') {
            next();
            return null;
          }
          break;
      }
      error("Syntax error");
    }

    function val() {
      white();
      switch (ch) {
        case '{':
          return obj();
        case '[':
          return arr();
        case '<':
          return assoc();
        case '"':
          return str();
        case '-':
          return num();
        default:
          return ch >= '0' && ch <= '9' ? num() : word();
      }
    }

    return val();
  }
};