define([
    'jquery',
    'underscore',
    'Mirasvit_PushNotification/js/debugger',
    'Mirasvit_PushNotification/js/lib/firebase',
    'Mirasvit_PushNotification/js/deps'//prevent error: Cannot read property '*' of undefined
], function ($, _, debug) {
    'use strict';

    return {
        token:     null,
        messaging: null,

        isPermissionDenied: false,
        isSupported:        true,
        isSafari:           false,

        initialize: function () {
            if (this.isSafariBrowser()) {
                this.isSupported = false;
                debug.info("Safari browser is not supported");
                return;
            }

            firebase.initializeApp({
                messagingSenderId: PN_SENDER_ID
            });

            if ('Notification' in window) {
                debug.info("Browser is supported");
            } else {
                debug.error("Browser is not supported");

                this.isSupported = false;
                return;
            }

            this.messaging = firebase.messaging();

            this.messaging.getToken()
                .then(function (token) {
                    debug.info("Obtained token: " + token);

                    this.subscriptionUpdate(token);
                }.bind(this))
                .catch(function (err) {
                    debug.error(err);

                    this.isPermissionDenied = true;
                }.bind(this));

            var scope = location.protocol + '//' + location.hostname + (location.port ? ':' + location.port : '') + '/firebase-cloud-messaging-push-scope';

            this.messaging.onMessage(function (payload) {
                debug.info(payload);

                navigator.serviceWorker.getRegistration(scope)
                    .then(function (registration) {
                        var data = payload.data;

                        var id = data.tag;
                        fetch(location.origin + '/push_notification/action/track?fb=0&event=fetch&id=' + id);

                        var notification = data;
                        notification.data = data;

                        if (registration) {
                            return registration.showNotification(notification.title, notification);
                        } else {
                            navigator.serviceWorker.register('/firebase-messaging-sw.js');
                            Notification.requestPermission(function (result) {
                                if (result === 'granted') {
                                    navigator.serviceWorker.ready.then(function (registration) {
                                        return registration.showNotification(notification.title, notification);
                                    });
                                }
                            });
                        }
                    });
            });

        },

        subscribe: function () {
            debug.info("Request permission...");

            this.messaging.requestPermission()
                .then(function () {
                    debug.info("accepted");

                    this.messaging.getToken()
                        .then(function (token) {
                            debug.info("Token: " + token);
                            this.subscriptionUpdate(token);
                        }.bind(this))
                        .catch(function (err) {
                            debug.error(err);
                        });
                }.bind(this))
                .catch(function (err) {
                    debug.error(err);

                    if (Notification.permission === 'denied') {
                        this.isPermissionDenied = true;
                    }
                }.bind(this));
        },

        subscriptionUpdate: function (token) {
            debug.info("Update subscription");

            if (!this.token) {
                this.token = token;
                this.ensureSubscription();
            }
        },

        ensureSubscription: function () {
            debug.info('Ensure subscription');
            $.ajax(window.PN_SUBSCRIBE_URL, {
                method: 'post',
                data:   {
                    token: this.token
                }
            });
        },

        isSafariBrowser: function() {
            let chromeAgent = navigator.userAgent.indexOf("Chrome") > -1;
            let safariAgent = navigator.userAgent.indexOf("Safari") > -1;
            this.isSafari = safariAgent && !chromeAgent;

            return this.isSafari;
        }
    };
});