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    if (localStorage.getItem("metalliganot_following") == null)
    {
        localStorage.setItem("metalliganot_following", "[]");
    }
    
    function addFollowButtons()
    {
        const games = document.querySelectorAll(".live .game");
        for (let i=0; i < games.length; i++)
        {
            const game = games[i];
            const gameId = game.getAttribute("id");
            let checker = document.createElement("button");
            checker.setAttribute("data-game-id", gameId);
            checker.innerText = JSON.parse(localStorage.getItem("metalliganot_following")).indexOf(gameId) > -1 ? "Følg ikke" : "Følg"
            checker.addEventListener("click", function() {
                toggleFollowing(gameId);
                this.innerText = this.innerText == "Følg" ? "Følg ikke" : "Følg";
            });
            game.insertBefore(checker, game.firstChild);
        }
    }

    function toggleFollowing(gameId)
    {
        var following = JSON.parse(localStorage.getItem("metalliganot_following"));
        var indexOfGameId = following.indexOf(gameId);

        if (indexOfGameId > -1) {
            following.splice(indexOfGameId, 1);
        }
        else {
            following.push(gameId);
        }
        
        localStorage.setItem("metalliganot_following", JSON.stringify(following));
    }

    function isFollowing(gameId)
    {
        var following = JSON.parse(localStorage.getItem("metalliganot_following"));
        return following.indexOf(gameId) > -1;
    }

    var seenEvents = [];
    
    function initSeenEvents()
    {
        
        fetch("/api/FallbackLive/Register?tournamentID=1374&getNews=false&getLiveBlog=false").then(function(response) {
            return response.json();
        }).then(function(games) {
            console.log(games);

            for (let i=0; i<games.length; i++)
            {
                var game = games[i];
                for (let e=0; e<game.events.length; e++)
                {
                    var ev = game.events[e];
                    ev.gameID = game.gameID;
                    seenEvents.push(JSON.stringify(ev));
                }
            }
        });
    }

    function hasSeenEvent(gameID, ev)
    {
        ev.gameID = gameID;
        return seenEvents.indexOf(JSON.stringify(ev)) > -1;
    }

    function notifyEvent(game, ev)
    {
        if(window.Notification && Notification.permission !== "denied") {
            Notification.requestPermission(function(status) {  // status is "granted", if accepted by user
                new Notification(game.homeTeamName + " - " + game.awayTeamName, { 
                    body: ev.eventText,
                    icon: 'http://www.hockeyligaen.dk/' + game.gameID + '.png' // optional
                }); 
            });
        }
    }

    setInterval(function() {

        fetch("/api/FallbackLive/Register?tournamentID=1374&getNews=false&getLiveBlog=false").then(function(response) {
            return response.json();
        }).then(function(games) {
            console.log(games);

            for (let i=0; i<games.length; i++)
            {
                const game = games[i];

                if (isFollowing(game.gameID.toString()))
                {
                    console.log("following " + game.gameID);
                    var events = game.events.reverse().filter(ev => seenEvents.indexOf(JSON.stringify(ev)) < 0);
                    for (let e=0; e<events.length; e++)
                    {
                        var ev = events[e];
                        if (!hasSeenEvent(game.gameID, ev))
                        {
                            console.log(ev);
                            
                            seenEvents.push(JSON.stringify(events[e]));
                            if (["Penalty","Goal","Period", "Comment", "Blog", "Spectators"].indexOf(ev.eventType) > -1)
                            {
                                notifyEvent(game, ev);
                            }
                        }
                    }
                }
            }

        });

    }, 15000);

    initSeenEvents();
    addFollowButtons();