/* Copyright (c) 2010 Marcus Westin
*
* 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.
*/

jQuery.store = (function(){
var api = {},
win = window,
doc = win.document,
localStorageName = 'localStorage',
globalStorageName = 'globalStorage',
storage

api.disabled = false
api.set = function(key, value) {}
api.get = function(key) {}
api.remove = function(key) {}
api.clear = function() {}
api.transact = function(key, transactionFn) {
var val = api.get(key)
if (typeof val == 'undefined') { val = {} }
transactionFn(val)
api.set(key, val)
}

api.serialize = function(value) {
    if ($.toJSON) {
        return $.toJSON(value);
    }
}
api.deserialize = function(value) {
if (typeof value != 'string') { return undefined }
return eval(value);
}

// Functions to encapsulate questionable FireFox 3.6.13 behavior
// when about.config::dom.storage.enabled === false
// See https://github.com/marcuswestin/store.js/issues#issue/13
function isLocalStorageNameSupported() {
try { return (localStorageName in win && win[localStorageName]) }
catch(err) { return false }
}

function isGlobalStorageNameSupported() {
try { return (globalStorageName in win && win[globalStorageName] && win[globalStorageName][win.location.hostname]) }
catch(err) { return false }
}

if (isLocalStorageNameSupported()) {
storage = win[localStorageName]
api.set = function(key, val) { storage.setItem(key, api.serialize(val)) }
api.get = function(key) { return api.deserialize(storage.getItem(key)) }
api.remove = function(key) { storage.removeItem(key) }
api.clear = function() { storage.clear() }

} else if (isGlobalStorageNameSupported()) {
storage = win[globalStorageName][win.location.hostname]
api.set = function(key, val) { storage[key] = api.serialize(val) }
api.get = function(key) { return api.deserialize(storage[key] && storage[key].value) }
api.remove = function(key) { delete storage[key] }
api.clear = function() { for (var key in storage ) { delete storage[key] } }

} else if (doc.documentElement.addBehavior) {
var storage = doc.createElement('div')
function withIEStorage(storeFunction) {
return function() {
var args = Array.prototype.slice.call(arguments, 0)
args.unshift(storage)
// See http://msdn.microsoft.com/en-us/library/ms531081(v=VS.85).aspx
// and http://msdn.microsoft.com/en-us/library/ms531424(v=VS.85).aspx
doc.body.appendChild(storage)
storage.addBehavior('#default#userData')
storage.load(localStorageName)
var result = storeFunction.apply(api, args)
doc.body.removeChild(storage)
return result
}
}
api.set = withIEStorage(function(storage, key, val) {
storage.setAttribute(key, api.serialize(val))
storage.save(localStorageName)
})
api.get = withIEStorage(function(storage, key) {
return api.deserialize(storage.getAttribute(key))
})
api.remove = withIEStorage(function(storage, key) {
storage.removeAttribute(key)
storage.save(localStorageName)
})
api.clear = withIEStorage(function(storage) {
var attributes = storage.XMLDocument.documentElement.attributes
storage.load(localStorageName)
for (var i=0, attr; attr = attributes[i]; i++) {
storage.removeAttribute(attr.name)
}
storage.save(localStorageName)
})
} else {
api.disabled = true
}

return api
})();