(function (win) {
    var PERMISSION_DEFAULT = "default",
        PERMISSION_GRANTED = "granted",
        PERMISSION_DENIED = "denied",
        PERMISSION = [PERMISSION_GRANTED, PERMISSION_DEFAULT, PERMISSION_DENIED],
        defaultSetting = {
            pageVisibility: false,
            autoClose: 0
        }, empty = {}, emptyString = "",
        isSupported = (function () {
            var isSupported = false;
            try {
                isSupported = !! (win.Notification || win.webkitNotifications || navigator.mozNotification || (win.external && win.external.msIsSiteMode() !== undefined));
            } catch (e) {}
            return isSupported;
        }()),
        ieVerification = Math.floor((Math.random() * 10) + 1),
        isFunction = function (value) {
            return (value && (value).constructor === Function);
        }, isString = function (value) {
            return (value && (value).constructor === String);
        }, isObject = function (value) {
            return (value && (value).constructor === Object);
        }, mixin = function (target, source) {
            var name, s;
            for (name in source) {
                s = source[name];
                if (!(name in target) || (target[name] !== s && (!(name in empty) || empty[name] !== s))) {
                    target[name] = s;
                }
            }
            return target;
        }, noop = function () {}, settings = defaultSetting;

    function getNotification(title, options) {
        var notification;
        if (win.Notification) {
            notification = new win.Notification(title, {
                icon: isString(options.icon) ? options.icon : options.icon.x32,
                body: options.body || emptyString,
                tag: options.tag || emptyString
            });
            if (isFunction(options.onclick)) {
                notification.onclick = options.onclick;
            }
        } else if (win.webkitNotifications) {
            notification = win.webkitNotifications.createNotification(options.icon, title, options.body);
            if (isFunction(options.onclick)) {
                notification.onclick = options.onclick;
            }
            notification.show();
        } else if (navigator.mozNotification) {
            notification = navigator.mozNotification.createNotification(title, options.body, options.icon);
            if (isFunction(options.onclick)) {
                notification.onclick = options.onclick;
            }
            notification.show();
        } else if (win.external && win.external.msIsSiteMode()) {
            win.external.msSiteModeClearIconOverlay();
            win.external.msSiteModeSetIconOverlay((isString(options.icon) ? options.icon : options.icon.x16), title);
            win.external.msSiteModeActivate();
            notification = {
                "ieVerification": ieVerification + 1
            };
        }
        return notification;
    }

    function getWrapper(notification) {
        return {
            close: function () {
                if (notification) {
                    if (notification.close) {
                        notification.close();
                    } else if (win.external && win.external.msIsSiteMode()) {
                        if (notification.ieVerification === ieVerification) {
                            win.external.msSiteModeClearIconOverlay();
                        }
                    }
                }
            }
        };
    }

    function requestPermission(callback) {
        if (!isSupported) {
            return;
        }
        var callbackFunction = isFunction(callback) ? callback : noop;
        if (win.webkitNotifications && win.webkitNotifications.checkPermission) {
            win.webkitNotifications.requestPermission(callbackFunction);
        } else if (win.Notification && win.Notification.requestPermission) {
            win.Notification.requestPermission(callbackFunction);
        }
    }

    function permissionLevel() {
        var permission;
        if (!isSupported) {
            return;
        }
        if (win.Notification && win.Notification.permissionLevel) {
            permission = win.Notification.permissionLevel();
        } else if (win.webkitNotifications && win.webkitNotifications.checkPermission) {
            permission = PERMISSION[win.webkitNotifications.checkPermission()];
        } else if (navigator.mozNotification) {
            permission = PERMISSION_GRANTED;
        } else if (win.Notification && win.Notification.permission) {
            permission = win.Notification.permission;
        } else if (win.external && (win.external.msIsSiteMode() !== undefined)) {
            permission = win.external.msIsSiteMode() ? PERMISSION_GRANTED : PERMISSION_DEFAULT;
        }
        return permission;
    }

    function config(params) {
        if (params && isObject(params)) {
            mixin(settings, params);
        }
        return settings;
    }

    function isDocumentHidden() {
        return settings.pageVisibility ? (document.hidden || document.msHidden || document.mozHidden || document.webkitHidden) : true;
    }

    function createNotification(title, options) {
        var notification, notificationWrapper;
        if (isSupported && isDocumentHidden() && isString(title) && (options && (isString(options.icon) || isObject(options.icon))) && (permissionLevel() === PERMISSION_GRANTED)) {
            notification = getNotification(title, options);
        }
        notificationWrapper = getWrapper(notification);
        if (settings.autoClose && notification && !notification.ieVerification && notification.addEventListener) {
            notification.addEventListener("show", function () {
                var notification = notificationWrapper;
                win.setTimeout(function () {
                    notification.close();
                }, settings.autoClose);
            });
        }
        return notificationWrapper;
    }
    win.notify = {
        PERMISSION_DEFAULT: PERMISSION_DEFAULT,
        PERMISSION_GRANTED: PERMISSION_GRANTED,
        PERMISSION_DENIED: PERMISSION_DENIED,
        isSupported: isSupported,
        config: config,
        createNotification: createNotification,
        permissionLevel: permissionLevel,
        requestPermission: requestPermission
    };
    if (isFunction(Object.seal)) {
        Object.seal(win.notify);
    }
}(window));