// ===============================
// INITIAL SETUP
// ===============================
let currentSongIndex = 0;
let SONG_LINKS = [];
let PLAYLIST = document.getElementById("playlistLeft");
let AUDIO_PLAYER = document.getElementById("navMusic");
let TRACK_NAME_DISPLAY = document.getElementById("currentSongInfo");

let NAV_PLAY = document.getElementById("navMusicPlay");
let NAV_PAUSE = document.getElementById("navMusicPause");
let NAV_NEXT = document.getElementById("navMusicNext");
let NAV_PREV = document.getElementById("navMusicPrevious");


// ===============================
// UNIVERSAL AUDIO URL SANITIZER
// ===============================
function sanitizeAudioUrl(raw) {
  if (!raw) return null;

  // Reject placeholders or HTML anchors
  if (raw === "#" || raw === "/" || raw === "./" || raw === "../") return null;

  // Allowed audio extensions
  const audioExtensions = [
    ".mp3", ".ogg", ".wav", ".m4a", ".aac", ".flac", ".opus", ".webm"
  ];

  const lower = raw.toLowerCase();
  const isAudio = audioExtensions.some(ext => lower.endsWith(ext));
  if (!isAudio) return null;

  // Absolute URL
  if (raw.startsWith("http")) return raw;

  // JSON gives /music/... or /audio/...
  if (raw.startsWith("/")) {
    return "https://frutigeraeroarchive.org" + raw;
  }

  // Otherwise treat as relative filename
  return "https://frutigeraeroarchive.org/music/" + raw;
}


// ===============================
// LOAD MUSIC DATA (CORS PROXY)
// ===============================
async function loadMusicData() {
  const response = await fetch(
    "https://corsproxy.io/?url=https%3A%2F%2Ffrutigeraeroarchive.org%2Fdata%2Fmusic.min.json"
  );

  const data = await response.json();

  const section = data.ols.find(item => item["@id"] === "frutigerAeroBliss");
  if (!section) return [];

  // KEEP JSON ORDER EXACTLY, but filter invalid URLs
  return section.li
  .map(item => {
    const fixedUrl = sanitizeAudioUrl(item.a["@data-src-mp3"]);
    if (!fixedUrl) return null;

    return {
      ...item.a,
      "@data-src-mp3": fixedUrl
    };
  })
  .filter(Boolean);
}


// ===============================
// CREATE PLAYLIST
// ===============================
function createAlbum(album) {
  if (!PLAYLIST) return;

  const existing = PLAYLIST.querySelector("ol");
  if (existing) existing.remove();

  const list = document.createElement("ol");
  list.id = album["@id"];

  const title = document.createElement("span");
  title.textContent = album.span;
  list.appendChild(title);

  const small = document.createElement("small");
  small.textContent = album.small;
  list.appendChild(small);

  // Build playlist ONLY from valid songs
  album.li.forEach((song, index) => {
    const li = document.createElement("li");
    const a = document.createElement("a");

    a.textContent = song.a.title;
    a.href = "#";

    for (const key in song.a) {
      if (key.startsWith("@data-")) {
        a.setAttribute(key.replace("@", ""), song.a[key]);
      }
    }

    li.appendChild(a);
    list.appendChild(li);
  });

  PLAYLIST.appendChild(list);

  SONG_LINKS = PLAYLIST.querySelectorAll("a[data-src-mp3]");

  SONG_LINKS.forEach((song, index) => {
    song.addEventListener("click", (e) => {
      e.preventDefault();
      currentSongIndex = index;
      updateSong(index);
    });
  });

  currentSongIndex = 0;
  updateSong(0);
}


// ===============================
// UPDATE SONG
// ===============================
function updateSong(index) {
  SONG_LINKS.forEach((song, i) => {
    song.classList.toggle("activeSong", i === index);
  });

  const song = SONG_LINKS[index];
  const src = song.getAttribute("data-src-mp3");

  if (!src) {
    console.warn("Invalid song URL, skipping.");
    return;
  }

  AUDIO_PLAYER.src = src;
  TRACK_NAME_DISPLAY.textContent = song.getAttribute("data-title");

  AUDIO_PLAYER.play().catch(console.error);
}


// ===============================
// NEXT / PREVIOUS
// ===============================
function nextTrack() {
  currentSongIndex = (currentSongIndex + 1) % SONG_LINKS.length;
  updateSong(currentSongIndex);
}

function previousTrack() {
  currentSongIndex = (currentSongIndex - 1 + SONG_LINKS.length) % SONG_LINKS.length;
  updateSong(currentSongIndex);
}

AUDIO_PLAYER.addEventListener("ended", nextTrack);


// ===============================
// NAV BUTTONS
// ===============================
NAV_PLAY.addEventListener("click", () => AUDIO_PLAYER.play());
NAV_PAUSE.addEventListener("click", () => AUDIO_PLAYER.pause());
NAV_NEXT.addEventListener("click", nextTrack);
NAV_PREV.addEventListener("click", previousTrack);


// ===============================
// LOAD ON STARTUP
// ===============================
window.addEventListener("load", async () => {
  const songs = await loadMusicData();
  if (songs.length > 0) {
    createAlbum({
      "@id": "frutigerAeroBliss",
      span: "Frutiger Aero Bliss",
      small: "Music that fits well with Frutiger Aero.",
      li: songs.map(song => ({ a: song }))
    });
  }
});