/**
 * Provides a simple interface for creating, retrieving and clearing cookies.
 */
var CookieManager = function(){
    this.cookieShelfLife = 365;
};
CookieManager.prototype =
{
    BROWSER_IS_IE:
        (document.all
         && window.ActiveXObject
         && navigator.userAgent.toLowerCase().indexOf("msie") > -1
         && navigator.userAgent.toLowerCase().indexOf("opera") == -1),

    /**
     * I hate navigator string based browser detection too, but when Opera alone
     * chokes on cookies containing double quotes...
     */
    BROWSER_IS_OPERA:
        (navigator.userAgent.toLowerCase().indexOf("opera") != -1),

    /**
     * Returns the value of a cookie with the given name, or <code>null</code>
     * if no such cookie exists.
     */
    getCookie: function(aCookieName)
    {
        var result = null;
        for (var i = 0; i < document.cookie.split('; ').length; i++)
        {
            var crumb = document.cookie.split('; ')[i].split('=');
            if (crumb[0] == aCookieName && crumb[1] != null)
            {
                result = crumb[1];
                break;
            }
        }

        if (this.BROWSER_IS_OPERA && result != null)
        {
            result = result.replace(/%22/g, '"');
        }
        return result;
    },

    /**
     * Sets a cookie with the given name and value.
     */
    setCookie: function(aCookieName, aCookieValue)
    {
        if (this.BROWSER_IS_OPERA)
        {
            aCookieValue = aCookieValue.replace(/"/g, "%22");
        }
        var date = new Date();
        date.setTime(date.getTime() + (this.cookieShelfLife * 24*60*60*1000));
        var expires = '; expires=' + date.toGMTString();
        document.cookie = aCookieName + '=' + aCookieValue + expires + '; path=/';
    },

    /**
     * Clears the cookie with the given name.
     */
    clearCookie: function(aCookieName)
    {
        if (this.BROWSER_IS_IE && this.userDataForIE)
        {
            this.store.load(this.IE_CACHE_NAME);
            this.store.removeAttribute(aCookieName);
            this.store.save(this.IE_CACHE_NAME);
        }
        else
        {
            document.cookie =
                aCookieName + '=;expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/';
        }
    }
}