window.addEventListener("load", function() {
    /** Carousel Script **/
    let slideIndex = 1;
    const autoPlaySlide = function() {
        plusSlides(1, false);
    }
    let resetTimer = setInterval(autoPlaySlide, 6000);
    showSlides(slideIndex);
    function plusSlides(n, resetAutoPlay) {
        showSlides(slideIndex += n, resetAutoPlay);
    }

    function showSlides(n, resetAutoPlay) {
        let isPaused = document.getElementsByClassName('nsu-play');
        if (resetAutoPlay && !isPaused && isPaused.length < 1) {
            clearInterval(resetTimer);
        }
        let i;
        let slides = document.getElementsByClassName("gradcarousel__slide");
        if (n > slides.length) {slideIndex = 1}
        if (n < 1) {slideIndex = slides.length}
        for (i = 0; i < slides.length; i++) {
            slides[i].style.display = "none";
        }


        slides[slideIndex-1].style.display = "block";
        if (resetAutoPlay && !isPaused && isPaused.length < 1) {
            resetTimer = setInterval(autoPlaySlide, 6000);
        }
    }

    function pausePlaySlides(control) {
        if (control == 'pause') {
            clearInterval(resetTimer);
        } else {
            resetTimer = setInterval(autoPlaySlide, 6000);
        }
    }

    document.getElementById('gradSlidePrev').addEventListener('click', function(e){
        e.preventDefault();
        plusSlides(-1, true);
    });

    document.getElementById('gradSlideNext').addEventListener('click', function(e){
        e.preventDefault();
        plusSlides(1, true);
    });

    document.getElementById('gradSlidePausePlay').addEventListener('click', function(e){
        e.preventDefault();
        let pauseSlide = this.firstChild.className.includes('nsu-pause');
        if (pauseSlide) {
            pausePlaySlides('pause');
            this.firstChild.classList.remove('nsu-pause');
            this.firstChild.classList.add('nsu-play');
            this.firstChild.textContent = 'play_arrow'
        } else {
            pausePlaySlides('play');
            this.firstChild.classList.add('nsu-pause');
            this.firstChild.classList.remove('nsu-play');
            this.firstChild.textContent = 'pause'
        }
    })
    /** End Carousel Script **/
});