/**
 * History
 *
/**
 *  Prototype Xtensions 
 *  
 *  @author    Simon Martins
 *  @copyright (c) 2008 Netatoo SARL <http://www.netatoo.fr>
 *  @license   MIT License <http://www.prototypextensions.com/#main=license>
 * 
 *  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.
 *
 */

var History = {
    __altered: false,
    __currentHash: null,
    __previousHash: null,
    __iframe: false,
    __title: false,
    
    /**
     * init()
     * @desc Initialize the hash. Call this method in first
     */
    init: function() {
        var inst  = this;
        var hash  = location.hash.substring(1);
        this.hash = $H(hash.toQueryParams());
        this.__currentHash  = hash;
        this.__previousHash = hash;

        this.__title = document.title;
        
        if(Ext.isIE && !Ext.isIE8) {
            document.observe('dom:loaded', function(e) {
                if(!$('px-historyframe')) {
                    History.__iframe = new Element('iframe', {
                        name   : 'px-historyframe',
                        id     : 'px-historyframe',
                        src    : '',
                        width  : '0',
                        height : '0',
                        style  : {
                            visibility: 'hidden'
                        }
                    });
                    
                    document.body.appendChild(History.__iframe);
                    
                    History.setHashOnIframe(inst.hash.toQueryString());
                }
            });
        }
    },
    
    /**
     * set( string $name, string $value )
     *
     * @desc Set new value $value for parameter $name
     */
    set: function($name, $value) {
        this.__previousHash = this.hash.toQueryString();
        this.hash.set($name, $value);
        this.apply();
    },
    
    /**
     * get( string $name )
     *
     * @desc Get value parameter $name
     */
    get: function($name) {
        return this.hash.get($name);
    },
    
    /**
     * unset( string $name )
     *
     * @desc Unset parameter $name
     */
    unset: function($name) {
        this.hash.unset($name);
        this.apply();
    },
    
    /**
     * update()
     *
     * @desc Updates this.hash with the current hash
     */
    update: function() {
        this.__previousHash = this.hash.toQueryString();
        var hash = window.location.hash.substring(1);

        // If IE, look in the iframe if the hash is updated
        if(Prototype.Browser.IE && Prototype.X.Browser.IE < 8 && this.__iframe ) {
            var hashInFrame = this.getHashOnIframe();
            
            if(hashInFrame != hash) {
                hash = hashInFrame;
            }
        }

        this.hash = $H(hash.toQueryParams());
        this.__currentHash = hash;
    },
    
    /**
     * apply()
     *
     * @desc Apply this.hash to location.hash
     */
    apply: function() {
        var newHash = this.hash.toQueryString();

        // set new hash
        window.location.hash = newHash;
        
        // If IE, apply new hash to frame for history    
        if(Prototype.Browser.IE && Prototype.X.Browser.IE < 8 && this.__iframe) {
            if(this.__currentHash != newHash) 
            {
                this.setHashOnIframe(newHash);   
            }
            else if(newHash != this.getHashOnIframe()) 
            {
                this.setHashOnIframe(newHash);    
            }
        }
    },

    /**
     * isAltered()
     *
     * @desc Return true if current hash is different of previous hash.
     * this.__altered allows to force the dispatch.
     */
    isAltered: function() {
        if(this.__altered == true) {
            return true;
        }
        this.__altered = false;

        return (History.__currentHash != History.__previousHash);
    },
    
    /**
     * setHashOnIframe()
     *
     * @use  For IE compatibility
     * @desc Set hash value on iframe
     */
    setHashOnIframe: function(hash) {
        try {
            var doc = History.__iframe.contentWindow.document;
            doc.open();
            doc.write('<html><body id="history">' + hash + '</body></html>');
            doc.close();
        } catch(e) {}
    },
    
    /**
     * getHashOnIframe()
     *
     * @use  For IE compatibility
     * @desc Get hash value on iframe
     */
    getHashOnIframe: function() {
        var doc = this.__iframe.contentWindow.document;
        if (doc && doc.body.id == 'history') {
            return doc.body.innerText;
        } else {
            return this.hash.toQueryString();
        }
    },
    
    /**
     * setTitle()
     *
     * @desc Set a new title for window
     */
    setTitle: function(title) {
        if(document.title) {
            document.title = title;
        }
    },
    
    /**
     * getTitle()
     *
     * @desc Return current window title
     */
    getTitle: function() {
        return this.__title;
    }
};

History.init();