/**
   Copyright (c) 2005, Brad Neuberg, bkn3@columbia.edu
   http://codinginparadise.org
   
   Permission is hereby granted, free of charge, to any person obtaining 
   a copy of this software and associated documentation files (the "Software"), 
   to deal in the Software without restriction, including without limitation 
   the rights to use, copy, modify, merge, publish, distribute, sublicense, 
   and/or sell copies of the Software, and to permit persons to whom the 
   Software is furnished to do so, subject to the following conditions:
   
   The above copyright notice and this permission notice shall be 
   included in all copies or substantial portions of the Software.
   
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
   IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
   CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT 
   OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
   THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   
   The JSON class near the end of this file is
   Copyright 2005, JSON.org
*/

window.dhtmlHistory = {
   initialize: function() {
      if (this.isInternetExplorer() == false) {
         return;
      }
      if (historyStorage.hasKey("DhtmlHistory_pageLoaded") == false) {
         this.fireOnNewListener = false;
         this.firstLoad = true;
         historyStorage.put("DhtmlHistory_pageLoaded", true);
      }
      else {
         this.fireOnNewListener = true;
         this.firstLoad = false;   
      }
   },
   addListener: function(callback) {
      this.listener = callback;
      if (this.fireOnNewListener == true) {
         this.fireHistoryEvent(this.currentLocation);
         this.fireOnNewListener = false;
      }
   },
   
   add: function(newLocation, historyData) {
      var self = this;
      var addImpl = function() {
         if (self.currentWaitTime > 0)
            self.currentWaitTime = self.currentWaitTime - self.WAIT_TIME;
         newLocation = self.removeHash(newLocation);
         var idCheck = document.getElementById(newLocation);
         if (idCheck != undefined || idCheck != null) {
            var message = 
               "Exception: History locations can not have "
               + "the same value as _any_ id's "
               + "that might be in the document, "
               + "due to a bug in Internet "
               + "Explorer; please ask the "
               + "developer to choose a history "
               + "location that does not match "
               + "any HTML id's in this "
               + "document. The following ID "
               + "is already taken and can not "
               + "be a location: " 
               + newLocation;
               
            throw message; 
         }
         historyStorage.put(newLocation, historyData);
         self.ignoreLocationChange = true;
         this.ieAtomicLocationChange = true;
         self.currentLocation = newLocation;
         window.location.hash = newLocation;
         if (self.isInternetExplorer())
            self.iframe.src = "blank.html?" + newLocation;
         this.ieAtomicLocationChange = false;
      };
      window.setTimeout(addImpl, this.currentWaitTime);
      this.currentWaitTime = this.currentWaitTime + this.WAIT_TIME;
   },   
   isFirstLoad: function() {
      if (this.firstLoad == true) {
         return true;
      }
      else {
         return false;
      }
   },   
   isInternational: function() {
      return false;
   },   
   getVersion: function() {
      return "0.05";
   },
   getCurrentLocation: function() {
      var currentLocation = this.removeHash(window.location.hash);         
      return currentLocation;
   },
    currentLocation: null,
    listener: null,
    iframe: null,
    ignoreLocationChange: null,
    WAIT_TIME: 200,
    currentWaitTime: 0,
    fireOnNewListener: null,
    firstLoad: null,
    ieAtomicLocationChange: null,
	
    create: function() {
      var initialHash = this.getCurrentLocation();
      this.currentLocation = initialHash;
      if (this.isInternetExplorer()) {
         document.write("<iframe style='border: 0px; width: 1px; "
                               + "height: 1px; position: absolute; bottom: 0px; "
                               + "right: 0px; visibility: visible;' "
                               + "name='DhtmlHistoryFrame' id='DhtmlHistoryFrame' "
                               + "src='blank.html?" + initialHash + "'>"
                               + "</iframe>");
         this.WAIT_TIME = 400;
      }
      var self = this;
      window.onunload = function() {
         self.firstLoad = null;
      };
      if (this.isInternetExplorer() == false) {
         if (historyStorage.hasKey("DhtmlHistory_pageLoaded") == false) {
            this.ignoreLocationChange = true;
            this.firstLoad = true;
            historyStorage.put("DhtmlHistory_pageLoaded", true);
         }
         else {
            this.ignoreLocationChange = false;
            this.fireOnNewListener = true;
         }
      }
      else {
         this.ignoreLocationChange = true;
      }      
      if (this.isInternetExplorer()) {
            this.iframe = document.getElementById("DhtmlHistoryFrame");
      }
      var self = this;
      var locationHandler = function() {
         self.checkLocation();
      };
      setInterval(locationHandler, 100);
   },
    fireHistoryEvent: function(newHash) {
      var historyData = historyStorage.get(newHash);
      this.listener.call(null, newHash, historyData);
   },
    checkLocation: function() {
      if (this.isInternetExplorer() == false
         && this.ignoreLocationChange == true) {
         this.ignoreLocationChange = false;
         return;
      }
      if (this.isInternetExplorer() == false
          && this.ieAtomicLocationChange == true) {
         return;
      }
      var hash = this.getCurrentLocation();
      if (hash == this.currentLocation)
         return;
      this.ieAtomicLocationChange = true;      
      if (this.isInternetExplorer()
          && this.getIFrameHash() != hash) {
         this.iframe.src = "blank.html?" + hash;
      }
      else if (this.isInternetExplorer()) {
         return;
      }
      this.currentLocation = hash;      
      this.ieAtomicLocationChange = false;
      this.fireHistoryEvent(hash);
   },
    getIFrameHash: function() {
      var historyFrame = document.getElementById("DhtmlHistoryFrame");
      var doc = historyFrame.contentWindow.document;
      var hash = new String(doc.location.search);
      if (hash.length == 1 && hash.charAt(0) == "?")
         hash = "";
      else if (hash.length >= 2 && hash.charAt(0) == "?")
         hash = hash.substring(1); 
		 return hash;
   },
    removeHash: function(hashValue) {
      if (hashValue == null || hashValue == undefined)
         return null;
      else if (hashValue == "")
         return "";
      else if (hashValue.length == 1 && hashValue.charAt(0) == "#")
         return "";
      else if (hashValue.length > 1 && hashValue.charAt(0) == "#")
         return hashValue.substring(1);
      else
         return hashValue;     
   },
    iframeLoaded: function(newLocation) {
      if (this.ignoreLocationChange == true) {
         this.ignoreLocationChange = false;
         return;
      }
      var hash = new String(newLocation.search);
      if (hash.length == 1 && hash.charAt(0) == "?")
         hash = "";
      else if (hash.length >= 2 && hash.charAt(0) == "?")
         hash = hash.substring(1);
      if (this.pageLoadEvent != true) {
         window.location.hash = hash;
      }
      this.fireHistoryEvent(hash);
   },
    isInternetExplorer: function() {
      var userAgent = navigator.userAgent.toLowerCase();
      if (document.all && userAgent.indexOf('msie')!=-1) {
         return true;
      }
      else {
         return false;
      }
   }
};

window.historyStorage = {
   debugging: false,
    storageHash: new Object(),
    hashLoaded: false,    
   put: function(key, value) {
       this.assertValidKey(key);
       if (this.hasKey(key)) {
         this.remove(key);
       }
       this.storageHash[key] = value;
       this.saveHashTable(); 
   },
   
   get: function(key) {
      this.assertValidKey(key);
      this.loadHashTable();      
      var value = this.storageHash[key];
      if (value == undefined)
         return null;
      else
         return value; 
   },
   
   remove: function(key) {
      this.assertValidKey(key);
      this.loadHashTable();
      delete this.storageHash[key];
      this.saveHashTable();
   },
   reset: function() {
      this.storageField.value = "";
      this.storageHash = new Object();
   },
   
   hasKey: function(key) {
      this.assertValidKey(key);
      this.loadHashTable();      
      if (typeof this.storageHash[key] == "undefined")
         return false;
      else
         return true;
   },
   isValidKey: function(key) {
      return (typeof key == "string");
   },
    storageField: null,
   
    init: function() {
      var styleValue = "position: absolute; top: -1000px; left: -1000px;";
      if (this.debugging == true) {
         styleValue = "width: 30em; height: 30em;";
      }   
      
      var newContent =
         "<form id='historyStorageForm' " 
               + "method='GET' "
               + "style='" + styleValue + "'>"
            + "<textarea id='historyStorageField' "
                      + "style='" + styleValue + "'"
                              + "left: -1000px;' "
                      + "name='historyStorageField'></textarea>"
         + "</form>";
      document.write(newContent);      
      this.storageField = document.getElementById("historyStorageField");
   },
    assertValidKey: function(key) {
      if (this.isValidKey(key) == false) {
       }
   },
    loadHashTable: function() {
      if (this.hashLoaded == false) {
         var serializedHashTable = this.storageField.value;         
         if (serializedHashTable != "" &&
             serializedHashTable != null) {
            this.storageHash = eval('(' + serializedHashTable + ')');  
         }
         
         this.hashLoaded = true;
      }
   },
    saveHashTable: function() {
      this.loadHashTable();
      var serializedHashTable = JSON.stringify(this.storageHash);
      this.storageField.value = serializedHashTable;
   }   
};
function setURL(_location){
	dhtmlHistory.add(_location);
}
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;
        switch (typeof arg) {
        case 'object':
            if (arg) {
                if (arg.______array == '______array') {
                    for (i = 0; i < arg.length; ++i) {
                        v = this.stringify(arg[i]);
                        if (s) {
                            s += ',';
                        }
                        s += v;
                    }
                    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 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 str();
                case '-':
                    return num();
                default:
                    return ch >= '0' && ch <= '9' ? num() : word();
            }
        }

        return val();
    }
};
window.historyStorage.init();
window.dhtmlHistory.create();