const video_formats = ["webm", "mp4"];
const audio_formats = ["mp3", "flac", "opus", "ogg", "m4a"];
const image_formats = ["jpg", "jpeg", "gif", "png", "bmp", "webp"];

const overlay = document.getElementById("overlay");
let   g_scale = 1;
let   g_volume = 1.0;

function mousescroll(e) {
    e.preventDefault();
    g_scale = Math.min(Math.max(0.25, g_scale + (e.deltaY * -0.001)), 4);
    e.target.style.transform = `scale(${g_scale})`;
}

function onvolumechange(e) {
    g_volume = e.target.volume;
}

const ext_filter = (ext, pathname) => pathname.toLowerCase().endsWith(ext);

function to_overlay(eltyp, pathname) {
    const el = document.createElement(eltyp);
    const el_label = document.createElement("span");
    el_label.textContent = decodeURI(pathname.substr(pathname.lastIndexOf("/") + 1));
    if (eltyp !== "audio") el.addEventListener('wheel', mousescroll);
    if (eltyp !== "img") {
        el.autoplay = el.controls = true;
        el.addEventListener("volumechange", onvolumechange);
        el.volume = g_volume;
    }
    el.src = pathname;
    overlay.appendChild(el);
    overlay.appendChild(el_label);
    overlay.style.visibility = "visible";
}

document.getElementById("overlay").addEventListener("click", e => {
    e.target.firstChild.remove();
    e.target.firstChild.remove();
    e.target.style.visibility = "hidden";
    g_scale = 1;
});

const file_links = Array.from(document.getElementsByTagName('tr')).slice(2).filter(e => e.lastChild.innerHTML != "DIR").map(l => l.firstChild.firstChild);

file_links.forEach(f => f.addEventListener('click', e => {
    const pathname = e.target.pathname;
    if (video_formats.some(ext => ext_filter(ext, pathname)))
        to_overlay("video", pathname);
    else if (audio_formats.some(ext => ext_filter(ext, pathname)))
        to_overlay("audio", pathname);
    else if (image_formats.some(ext => ext_filter(ext, pathname)))
        to_overlay("img", pathname);
    if (overlay.firstChild != null)
        e.preventDefault();
}));