const UI = {
    CLASSNAMES: {
        ITEM: 'event-item',
        YEAR: 'event-year',
        FLAG: 'event-flag',
        LOCATION: 'event-location',
    },

    DATA: {
        EVENT: 'data-event-key',
        ROUND: 'data-round-key',
        SORT: 'data-sort-key',
    },

    updateEventsPane: (eventKey) => {
        const events = document.querySelectorAll(`.${UI.CLASSNAMES.ITEM}`);
        
        events.forEach(node => {
            const classes = node.className.split(' ');
            classes.splice(1, classes.indexOf('active'));
            node.className = classes.join(' ');
        });

        const activeEventNode = document.querySelector(`[${UI.DATA.EVENT}="${eventKey}"`);
        activeEventNode.className += ' active';
    },

    buildEventsPane: (onClick) => {
        const eventsList = [
            { year: 1930, location: "Uruguay", icon: "uy" },
            { year: 1934, location: "Italy", icon: "it" },
            { year: 1938, location: "France", icon: "fr" },
            { year: 1954, location: "Switzerland", icon: "ch" },
            { year: 1958, location: "Sweden", icon: "se" },
            { year: 1962, location: "Chile", icon: "cl" },
            { year: 1966, location: "England", icon: "gb" },
            { year: 1970, location: "Mexico", icon: "mx" },
            { year: 1974, location: "West Germany", icon: "de" },
            { year: 1978, location: "Argentina", icon: "ar" },
            { year: 1982, location: "Spain", icon: "es" },
            { year: 1986, location: "Mexico", icon: "mx" },
            { year: 1990, location: "Italy", icon: "it" },
            { year: 1994, location: "USA", icon: "us" },
            { year: 1998, location: "France", icon: "fr" },
            { year: 2002, location: "Japan / South Korea", icon: "jp" },
            { year: 2006, location: "Germany", icon: "de" },
            { year: 2010, location: "Johannesburg", icon: "za" },
            { year: 2014, location: "Brazil", icon: "br" },
        ];

        const eventsDiv = document.querySelector('.events');

        while (eventsDiv.hasChildNodes()) {
            eventsDiv.firstChild.remove();
        }

        eventsList.forEach((evt) => {
            const item = document.createElement('div');
            const year = document.createElement('div');
            const location = document.createElement('div');
            const flag = document.createElement('div');
            const flagIcon = document.createElement('div');

            item.className = UI.CLASSNAMES.ITEM;
            year.className = UI.CLASSNAMES.YEAR;
            location.className = UI.CLASSNAMES.LOCATION;
            flag.className = UI.CLASSNAMES.FLAG;

            item.addEventListener('click', onClick);
            item.setAttribute('data-event-key', evt.year);

            year.innerHTML = evt.year;
            location.innerHTML = evt.location;
            flagIcon.className = `flag-icon flag-icon-${evt.icon}`;

            flag.appendChild(flagIcon);
            item.appendChild(flag);
            item.appendChild(year);
            item.appendChild(location);

            eventsDiv.appendChild(item);
        });
    },
};