/*
* jQuery history plugin
* 
* The MIT License
* 
* Copyright (c) 2006-2009 Taku Sano (Mikage Sawatari)
* Copyright (c) 2010 Takayuki Miwa
* 
* 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.
*/

(function ($) {
	var locationWrapper = {
		put: function (hash, win) {
			(win || window).location.hash = this.encoder(hash);
		},
		get: function (win) {
			var hash = ((win || window).location.hash).replace(/^#/, '');
			try {
				return $.browser.mozilla ? hash : decodeURIComponent(hash);
			}
			catch (error) {
				return hash;
			}
		},
		encoder: encodeURIComponent
	};

	var iframeWrapper = {
		id: "__jQuery_history",
		init: function () {
			var html = '<iframe id="' + this.id + '" style="display:none" src="javascript:false;" />';
			$("body").prepend(html);
			return this;
		},
		_document: function () {
			return $("#" + this.id)[0].contentWindow.document;
		},
		put: function (hash) {
			var doc = this._document();
			doc.open();
			doc.close();
			locationWrapper.put(hash, doc);
		},
		get: function () {
			return locationWrapper.get(this._document());
		}
	};

	function initObjects(options) {
		options = $.extend({
			unescape: false
		}, options || {});

		locationWrapper.encoder = encoder(options.unescape);

		function encoder(unescape_) {
			if (unescape_ === true) {
				return function (hash) { return hash; };
			}
			if (typeof unescape_ == "string" &&
               (unescape_ = partialDecoder(unescape_.split("")))
               || typeof unescape_ == "function") {
				return function (hash) { return unescape_(encodeURIComponent(hash)); };
			}
			return encodeURIComponent;
		}

		function partialDecoder(chars) {
			var re = new RegExp($.map(chars, encodeURIComponent).join("|"), "ig");
			return function (enc) { return enc.replace(re, decodeURIComponent); };
		}
	}

	var implementations = {};

	implementations.base = {
		callback: undefined,
		type: undefined,

		check: function () { },
		load: function (hash) { },
		init: function (callback, options) {
			initObjects(options);
			self.callback = callback;
			self._options = options;
			self._init();
		},

		_init: function () { },
		_options: {}
	};

	implementations.timer = {
		_appState: undefined,
		_init: function () {
			var current_hash = locationWrapper.get();
			self._appState = current_hash;
			self.callback(current_hash);
			setInterval(self.check, 100);
		},
		check: function () {
			var current_hash = locationWrapper.get();
			if (current_hash != self._appState) {
				self._appState = current_hash;
				self.callback(current_hash);
			}
		},
		load: function (hash) {
			if (hash != self._appState) {
				locationWrapper.put(hash);
				self._appState = hash;
				self.callback(hash);
			}
		}
	};

	implementations.iframeTimer = {
		_appState: undefined,
		_init: function () {
			var current_hash = locationWrapper.get();
			self._appState = current_hash;
			iframeWrapper.init().put(current_hash);
			self.callback(current_hash);
			setInterval(self.check, 100);
		},
		check: function () {
			var iframe_hash = iframeWrapper.get(),
                location_hash = locationWrapper.get();

			if (location_hash != iframe_hash) {
				if (location_hash == self._appState) {    // user used Back or Forward button
					self._appState = iframe_hash;
					locationWrapper.put(iframe_hash);
					self.callback(iframe_hash);
				} else {                              // user loaded new bookmark
					self._appState = location_hash;
					iframeWrapper.put(location_hash);
					self.callback(location_hash);
				}
			}
		},
		load: function (hash) {
			if (hash != self._appState) {
				locationWrapper.put(hash);
				iframeWrapper.put(hash);
				self._appState = hash;
				self.callback(hash);
			}
		}
	};

	implementations.hashchangeEvent = {
		_init: function () {
			self.callback(locationWrapper.get());
			$(window).bind('hashchange', self.check);
		},
		check: function () {
			self.callback(locationWrapper.get());
		},
		load: function (hash) {
			locationWrapper.put(hash);
		}
	};

	var self = $.extend({}, implementations.base);

	if ($.browser.msie && ($.browser.version < 8 || document.documentMode < 8)) {
		self.type = 'iframeTimer';
	} else if ("onhashchange" in window) {
		self.type = 'hashchangeEvent';
	} else {
		self.type = 'timer';
	}

	$.extend(self, implementations[self.type]);
	$.history = self;
})(jQuery);