window.dhtmlHistory = {

isIE: false,
isOpera: false,
isSafari: false,
isKonquerer: false,
isGecko: false,
isSupported: false,

create: function(options) {

var that = this;

var UA = navigator.userAgent.toLowerCase();
var platform = navigator.platform.toLowerCase();
var vendor = navigator.vendor || "";
if (vendor === "KDE") {
this.isKonqueror = true;
this.isSupported = false;
} else if (typeof window.opera !== "undefined") {
this.isOpera = true;
this.isSupported = true;
} else if (typeof document.all !== "undefined") {
this.isIE = true;
this.isSupported = true;
} else if (vendor.indexOf("Apple Computer, Inc.") > -1) {
this.isSafari = true;
this.isSupported = (platform.indexOf("mac") > -1);
} else if (UA.indexOf("gecko") != -1) {
this.isGecko = true;
this.isSupported = true;
}

window.historyStorage.setup(options);

if (this.isSafari) {
this.createSafari();
} else if (this.isOpera) {
this.createOpera();
}

var initialHash = this.getCurrentLocation();

this.currentLocation = initialHash;

if (this.isIE) {
this.createIE(initialHash);
}

var unloadHandler = function() {
that.firstLoad = null;
};
this.addEventListener(window,'unload',unloadHandler);

if (this.isIE) {

this.ignoreLocationChange = true;
} else {
if (!historyStorage.hasKey(this.PAGELOADEDSTRING)) {

this.ignoreLocationChange = true;
this.firstLoad = true;
historyStorage.put(this.PAGELOADEDSTRING, true);
} else {

this.ignoreLocationChange = false;

this.fireOnNewListener = true;
}
}

var locationHandler = function() {
that.checkLocation();
};
setInterval(locationHandler, 100);
},

initialize: function() {

if (this.isIE) {

if (!historyStorage.hasKey(this.PAGELOADEDSTRING)) {

this.fireOnNewListener = false;
this.firstLoad = true;
historyStorage.put(this.PAGELOADEDSTRING, true);
}

else {
this.fireOnNewListener = true;
this.firstLoad = false;
}
}
},

addListener: function(listener) {
this.listener = listener;

if (this.fireOnNewListener) {
this.fireHistoryEvent(this.currentLocation);
this.fireOnNewListener = false;
}
},

addEventListener: function(o,e,l) {
if (o.addEventListener) {
o.addEventListener(e,l,false);
} else if (o.attachEvent) {
o.attachEvent('on'+e,function() {
l(window.event);
});
}
},

add: function(newLocation, historyData) {
if (this.isSafari) {

newLocation = this.removeHash(newLocation);

historyStorage.put(newLocation, historyData);

this.currentLocation = newLocation;

window.location.hash = newLocation;

this.putSafariState(newLocation);
} else {

var that = this;
var addImpl = function() {

if (that.currentWaitTime > 0) {
that.currentWaitTime = that.currentWaitTime - that.waitTime;
}

newLocation = that.removeHash(newLocation);

if (document.getElementById(newLocation) && that.debugMode) {
var e = "Exception: History locations can not have the same value as _any_ IDs that might be in the document,"
+ " due to a bug in IE; please ask the developer to choose a history location that does not match any HTML"
+ " IDs in this document. The following ID is already taken and cannot be a location: " + newLocation;
throw new Error(e);
}

historyStorage.put(newLocation, historyData);

that.ignoreLocationChange = true;

that.ieAtomicLocationChange = true;

that.currentLocation = newLocation;

window.location.hash = newLocation;

if (that.isIE) {
that.iframe.src = blank_html_path + "blank.html?" + newLocation;
}

that.ieAtomicLocationChange = false;
};

window.setTimeout(addImpl, this.currentWaitTime);

this.currentWaitTime = this.currentWaitTime + this.waitTime;
}
},

isFirstLoad: function() {
return this.firstLoad;
},

getVersion: function() {
return "0.6";
},


getCurrentLocation: function() {
var r = (this.isSafari
? this.getSafariState()
: this.getCurrentHash()
);
return r;
},

getCurrentHash: function() {
var r = window.location.href;
var i = r.indexOf("#");
return (i >= 0
? r.substr(i+1)
: ""
);
},


PAGELOADEDSTRING: "DhtmlHistory_pageLoaded",

listener: null,

waitTime: 200,

currentWaitTime: 0,

currentLocation: null,

iframe: null,

safariHistoryStartPoint: null,
safariStack: null,
safariLength: null,

ignoreLocationChange: null,

fireOnNewListener: null,

firstLoad: null,

ieAtomicLocationChange: null,

createIE: function(initialHash) {

this.waitTime = 400;
var styles = (historyStorage.debugMode
? 'width: 800px;height:80px;border:1px solid black;'
: historyStorage.hideStyles
);
var iframeID = "rshHistoryFrame";
var iframeHTML = '<iframe frameborder="0" id="' + iframeID + '" style="' + styles + '" src="'+blank_html_path+'blank.html?' + initialHash + '"></iframe>';
document.write(iframeHTML);
this.iframe = document.getElementById(iframeID);
},

createOpera: function() {
this.waitTime = 400;
var imgHTML = '<img src="javascript:location.href=\'javascript:dhtmlHistory.checkLocation();\';" style="' + historyStorage.hideStyles + '" />';
document.write(imgHTML);
},

createSafari: function() {
var formID = "rshSafariForm";
var stackID = "rshSafariStack";
var lengthID = "rshSafariLength";
var formStyles = historyStorage.debugMode ? historyStorage.showStyles : historyStorage.hideStyles;
var inputStyles = (historyStorage.debugMode
? 'width:800px;height:20px;border:1px solid black;margin:0;padding:0;'
: historyStorage.hideStyles
);
var safariHTML = '<form id="' + formID + '" style="' + formStyles + '">'
+ '<input type="text" style="' + inputStyles + '" id="' + stackID + '" value="[]"/>'
+ '<input type="text" style="' + inputStyles + '" id="' + lengthID + '" value=""/>'
+ '</form>';
document.write(safariHTML);
this.safariStack = document.getElementById(stackID);
this.safariLength = document.getElementById(lengthID);
if (!historyStorage.hasKey(this.PAGELOADEDSTRING)) {
this.safariHistoryStartPoint = history.length;
this.safariLength.value = this.safariHistoryStartPoint;
} else {
this.safariHistoryStartPoint = this.safariLength.value;
}
},

getSafariStack: function() {
var r = this.safariStack.value;
return historyStorage.fromJSON(r);
},

getSafariState: function() {
var stack = this.getSafariStack();
var state = stack[history.length - this.safariHistoryStartPoint - 1];
return state;
},

putSafariState: function(newLocation) {
var stack = this.getSafariStack();
stack[history.length - this.safariHistoryStartPoint] = newLocation;
this.safariStack.value = historyStorage.toJSON(stack);
},

fireHistoryEvent: function(newHash) {

var historyData = historyStorage.get(newHash);

this.listener.call(null, newHash, historyData);
},

checkLocation: function() {

if (!this.isIE && this.ignoreLocationChange) {
this.ignoreLocationChange = false;
return;
}

if (!this.isIE && this.ieAtomicLocationChange) {
return;
}

var hash = this.getCurrentLocation();

if (hash == this.currentLocation) {
return;
}

this.ieAtomicLocationChange = true;
if (this.isIE && this.getIframeHash() != hash) {
this.iframe.src = blank_html_path + "blank.html?" + hash;
}
else if (this.isIE) {

return;
}

this.currentLocation = hash;
this.ieAtomicLocationChange = false;

this.fireHistoryEvent(hash);
},

getIframeHash: function() {
var doc = this.iframe.contentWindow.document;
var hash = 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) {
var r;
if (hashValue === null || hashValue === undefined) {
r = null;
}
else if (hashValue === "") {
r = "";
}
else if (hashValue.length == 1 && hashValue.charAt(0) == "#") {
r = "";
}
else if (hashValue.length > 1 && hashValue.charAt(0) == "#") {
r = hashValue.substring(1);
}
else {
r = hashValue;
}
return r;
},

iframeLoaded: function(newLocation) {

if (this.ignoreLocationChange) {
this.ignoreLocationChange = false;
return;
}

var hash = String(newLocation.search);
if (hash.length == 1 && hash.charAt(0) == "?") {
hash = "";
}
else if (hash.length >= 2 && hash.charAt(0) == "?") {
hash = hash.substring(1);
}

window.location.hash = hash;

this.fireHistoryEvent(hash);
}
};

window.historyStorage = {

setup: function(options) {


if (typeof options !== "undefined") {
if (options.debugMode) {
this.debugMode = options.debugMode;
}
if (options.toJSON) {
this.toJSON = options.toJSON;
}
if (options.fromJSON) {
this.fromJSON = options.fromJSON;
}
}

var formID = "rshStorageForm";
var textareaID = "rshStorageField";
var formStyles = this.debugMode ? historyStorage.showStyles : historyStorage.hideStyles;
var textareaStyles = (historyStorage.debugMode
? 'width: 800px;height:80px;border:1px solid black;'
: historyStorage.hideStyles
);
var textareaHTML = '<form id="' + formID + '" style="' + formStyles + '">'
+ '<textarea id="' + textareaID + '" style="' + textareaStyles + '"></textarea>'
+ '</form>';
document.write(textareaHTML);
this.storageField = document.getElementById(textareaID);
if (typeof window.opera !== "undefined") {
this.storageField.focus();
}
},

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) {
value = null;
}
return value;
},

remove: function(key) {
this.assertValidKey(key);

this.loadHashTable();

delete this.storageHash[key];

this.saveHashTable();
},

reset: function() {
this.storageField.value = "";
this.storageHash = {};
},

hasKey: function(key) {
this.assertValidKey(key);

this.loadHashTable();
return (typeof this.storageHash[key] !== "undefined");
},

isValidKey: function(key) {
return (typeof key === "string");
},

showStyles: 'border:0;margin:0;padding:0;',
hideStyles: 'left:-1000px;top:-1000px;width:1px;height:1px;border:0;position:absolute;',

debugMode: false,


storageHash: {},

hashLoaded: false,

storageField: null,

assertValidKey: function(key) {
var isValid = this.isValidKey(key);
if (!isValid && this.debugMode) {
throw new Error("Please provide a valid key for window.historyStorage. Invalid key = " + key + ".");
}
},

loadHashTable: function() {
if (!this.hashLoaded) {
var serializedHashTable = this.storageField.value;
if (serializedHashTable !== "" && serializedHashTable !== null) {
this.storageHash = this.fromJSON(serializedHashTable);
this.hashLoaded = true;
}
}
},

saveHashTable: function() {
this.loadHashTable();
var serializedHashTable = this.toJSON(this.storageHash);
this.storageField.value = serializedHashTable;
},

toJSON: function(o) {
return o.toJSONString();
},
fromJSON: function(s) {
return s.parseJSON();
}
};