const audio = document.getElementById("audio-player");
const btnPlay = document.getElementById("btn-play");
const btnPrev = document.getElementById("btn-prev");
const btnNext = document.getElementById("btn-next");
const btnShuffle = document.getElementById("btn-shuffle");
const btnRepeat = document.getElementById("btn-repeat");
const progressBar = document.getElementById("progress-bar");
const currentTimeEl = document.getElementById("current-time");
const durationEl = document.getElementById("duration");
const volumeSlider = document.getElementById("volume");
const playlistEl = document.getElementById("playlist");
const trackTitle = document.getElementById("track-title");
const trackIndex = document.getElementById("track-index");
const playlistCount = document.getElementById("playlist-count");

let playlist = [];
let currentIndex = 0;
let shuffle = false;
let repeat = false;
let shuffleOrder = [];

function formatTime(seconds) {
  if (isNaN(seconds)) return "0:00";
  const m = Math.floor(seconds / 60);
  const s = Math.floor(seconds % 60).toString().padStart(2, "0");
  return `${m}:${s}`;
}

function stripExtension(filename) {
  return filename.replace(/\.[^/.]+$/, "");
}

function buildShuffleOrder() {
  shuffleOrder = [...Array(playlist.length).keys()];
  for (let i = shuffleOrder.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [shuffleOrder[i], shuffleOrder[j]] = [shuffleOrder[j], shuffleOrder[i]];
  }
}

function loadTrack(index, autoplay = false) {
  currentIndex = index;
  const filename = playlist[index];
  audio.src = `/audio/${encodeURIComponent(filename)}`;
  trackTitle.textContent = stripExtension(filename);
  trackIndex.textContent = `Track ${index + 1} of ${playlist.length}`;
  document.querySelectorAll("#playlist li").forEach((li, i) => {
    li.classList.toggle("active", i === index);
    if (i === index) li.scrollIntoView({ block: "nearest" });
  });
  progressBar.value = 0;
  currentTimeEl.textContent = "0:00";
  durationEl.textContent = "0:00";
  if (autoplay) audio.play();
}

function playNext() {
  if (playlist.length === 0) return;
  if (shuffle) {
    const pos = shuffleOrder.indexOf(currentIndex);
    const nextPos = (pos + 1) % shuffleOrder.length;
    loadTrack(shuffleOrder[nextPos], true);
  } else {
    loadTrack((currentIndex + 1) % playlist.length, true);
  }
}

function playPrev() {
  if (playlist.length === 0) return;
  if (audio.currentTime > 3) {
    audio.currentTime = 0;
    return;
  }
  if (shuffle) {
    const pos = shuffleOrder.indexOf(currentIndex);
    const prevPos = (pos - 1 + shuffleOrder.length) % shuffleOrder.length;
    loadTrack(shuffleOrder[prevPos], true);
  } else {
    loadTrack((currentIndex - 1 + playlist.length) % playlist.length, true);
  }
}

function renderPlaylist() {
  playlistEl.innerHTML = "";
  playlistCount.textContent = `${playlist.length} track${playlist.length !== 1 ? "s" : ""}`;
  playlist.forEach((file, i) => {
    const li = document.createElement("li");
    li.textContent = stripExtension(file);
    li.title = file;
    li.addEventListener("click", () => loadTrack(i, true));
    playlistEl.appendChild(li);
  });
}

async function loadPlaylist() {
  try {
    const res = await fetch("/api/playlist");
    playlist = await res.json();
    renderPlaylist();
    if (playlist.length > 0) {
      buildShuffleOrder();
      loadTrack(0);
    } else {
      trackTitle.textContent = "No audio files found";
      trackIndex.textContent = "Drop .mp3 / .ogg / .wav files into the audio/ folder";
    }
  } catch (e) {
    trackTitle.textContent = "Error loading playlist";
  }
}

// Controls
btnPlay.addEventListener("click", () => {
  if (audio.paused) {
    if (!audio.src) loadTrack(0, true);
    else audio.play();
  } else {
    audio.pause();
  }
});

btnNext.addEventListener("click", playNext);
btnPrev.addEventListener("click", playPrev);

btnShuffle.addEventListener("click", () => {
  shuffle = !shuffle;
  btnShuffle.classList.toggle("active", shuffle);
  if (shuffle) buildShuffleOrder();
});

btnRepeat.addEventListener("click", () => {
  repeat = !repeat;
  btnRepeat.classList.toggle("active", repeat);
});

// Audio events
audio.addEventListener("play", () => { btnPlay.textContent = "⏸"; });
audio.addEventListener("pause", () => { btnPlay.textContent = "▶"; });

audio.addEventListener("timeupdate", () => {
  if (audio.duration) {
    progressBar.value = (audio.currentTime / audio.duration) * 100;
    currentTimeEl.textContent = formatTime(audio.currentTime);
  }
});

audio.addEventListener("loadedmetadata", () => {
  durationEl.textContent = formatTime(audio.duration);
});

audio.addEventListener("ended", () => {
  if (repeat) {
    audio.currentTime = 0;
    audio.play();
  } else {
    playNext();
  }
});

progressBar.addEventListener("input", () => {
  if (audio.duration) {
    audio.currentTime = (progressBar.value / 100) * audio.duration;
  }
});

volumeSlider.addEventListener("input", () => {
  audio.volume = volumeSlider.value / 100;
});

// Set initial volume
audio.volume = volumeSlider.value / 100;

// Keyboard shortcuts
document.addEventListener("keydown", (e) => {
  if (e.target.tagName === "INPUT") return;
  switch (e.key) {
    case " ": e.preventDefault(); btnPlay.click(); break;
    case "ArrowRight": playNext(); break;
    case "ArrowLeft": playPrev(); break;
    case "ArrowUp": volumeSlider.value = Math.min(100, +volumeSlider.value + 5); audio.volume = volumeSlider.value / 100; break;
    case "ArrowDown": volumeSlider.value = Math.max(0, +volumeSlider.value - 5); audio.volume = volumeSlider.value / 100; break;
  }
});

loadPlaylist();