// app.js — ani-web frontend: search -> detail -> play, vanilla JS + hls.js
const main = document.getElementById("main");
let hls = null, detail = null, lang = "eng", seasonId = null;

async function api(path) {
  const r = await fetch(path);
  if (!r.ok) {
    let msg = r.statusText;
    try { msg = (await r.json()).detail || msg; } catch {}
    throw new Error(msg);
  }
  return r.json();
}

function el(tag, cls, text) {
  const e = document.createElement(tag);
  if (cls) e.className = cls;
  if (text != null) e.textContent = text;
  return e;
}

function fail(err) {
  main.innerHTML = "";
  main.append(el("p", "error", "Error: " + err.message));
}

function showStreamError(msg) {
  const p = el("p", "error", "Stream error: " + msg);
  const player = document.getElementById("player");
  if (player) player.append(p); else fail(new Error(msg));
}

// ---------- history (server-persisted, incl. watch position) ----------
let history = [];
async function refreshHistory() {
  try { history = await api("/api/history"); } catch { /* home just shows empty */ }
}
function postHistory(entry) {
  fetch("/api/history", {method: "POST", headers: {"Content-Type": "application/json"},
    body: JSON.stringify(entry)}).catch(() => {});
}
const fmtPos = s => { s = Math.floor(s || 0); return `${Math.floor(s / 60)}:${String(s % 60).padStart(2, "0")}`; };

function showHome() {
  main.innerHTML = "";
  if (!history.length) { main.append(el("p", "muted", "Search for an anime to get started.")); return; }
  const sec = el("section");
  sec.append(el("h2", null, "Recently played"));
  for (const x of history.slice(0, 5)) {
    const b = el("button", "hist-item", `${x.title} — Ep ${x.ep} (${x.lang === "eng" ? "dub" : "sub"}) · ${fmtPos(x.pos)}`);
    b.onclick = () => location.href = `?anime=${x.slug_id}&season=${x.season_id}&ep=${x.ep_id}&lang=${x.lang}`;
    sec.append(b);
  }
  main.append(sec);
}

// ---------- search ----------
async function showSearch(q) {
  const results = await api(`/api/search?q=${encodeURIComponent(q)}`);
  main.innerHTML = "";
  if (!results.length) { main.append(el("p", "muted", "No results.")); return; }
  const grid = el("div", "grid");
  for (const r of results) {
    const card = el("a", "card");
    card.href = `?anime=${r.slug_id}`;
    const img = el("img", null, r.name);
    img.src = r.poster || "";
    card.append(img, el("span", "card-name", r.name));
    grid.append(card);
  }
  main.append(grid);
}

// ---------- detail + player ----------
async function showAnime(slug_id, opts = {}) {
  detail = await api(`/api/anime/${slug_id}`);
  lang = opts.lang || "eng";
  seasonId = opts.season || detail.id;
  detail.slug_id = slug_id;
  main.innerHTML = "";

  const head = el("section", "detail-head");
  head.append(el("h2", null, detail.name));
  main.append(head);

  const player = el("div", "player");
  player.id = "player";
  player.append(videoEl());
  main.append(player);

  const controls = el("div", "controls");
  const langBtn = el("button", null, langLabel());
  const setLang = l => { lang = l; langBtn.textContent = langLabel(); };
  langBtn.onclick = () => {
    setLang(lang === "eng" ? "jpn" : "eng");
    const cur = main.querySelector(".ep.active");
    if (cur) play(cur.dataset.ep, cur.dataset.no);
  };
  controls.append(langBtn, el("span", "muted", " — click an episode to play"));
  main.append(controls);

  const tabs = el("div", "tabs");
  for (const s of detail.seasons) {
    const t = el("button", "tab" + (s.id === seasonId ? " active" : ""), s.name);
    t.dataset.id = s.id;
    t.onclick = () => {
      for (const x of tabs.children) x.classList.toggle("active", +x.dataset.id === s.id);
      location.href = `?anime=${s.slug_id}&season=${s.id}&lang=${lang}`;
    };
    tabs.append(t);
  }
  main.append(tabs);

  const eps = el("div", "eps");
  eps.id = "eps";
  main.append(eps);

  const list = await api(`/api/anime/${seasonId}/episodes`);
  for (const e of list) {
    const b = el("button", "ep" + (e.filler ? " filler" : ""));
    b.textContent = "E" + e.number;
    if (e.filler) b.append(el("span", "badge", " filler"));
    b.dataset.ep = e.id; b.dataset.no = e.number;
    b.onclick = () => { markActive(b); play(e.id, e.number); };
    eps.append(b);
  }
  if (opts.ep) {
    const cur = [...eps.children].find(b => +b.dataset.ep === opts.ep);
    if (cur) { markActive(cur); play(opts.ep, cur.dataset.no); }
  } else {
    // default: resume last watched ep of this season, else start at ep 1
    const h = history.find(x => x.slug_id === slug_id && x.season_id === seasonId);
    const auto = h ? h.ep_id : +eps.querySelector(".ep")?.dataset.ep;
    if (auto) {
      const cur = [...eps.children].find(b => +b.dataset.ep === auto);
      if (cur) { markActive(cur); play(auto, cur.dataset.no); }
    }
  }

  if (detail.synopsis) main.append(el("p", "synopsis bottom", detail.synopsis));
}

function langLabel() { return lang === "eng" ? "▶ dub" : "▶ sub"; }

function markActive(b) {
  for (const x of document.querySelectorAll(".ep")) x.classList.remove("active");
  b.classList.add("active");
}

function videoEl() {
  const v = document.createElement("video");
  v.controls = true; v.autoplay = true;
  return v;
}

function stopHls() { if (hls) { hls.destroy(); hls = null; } }

let currentEp = null, lastSavedPos = 0;

async function play(ep_id, ep_no) {
  try {
    const s = await api(`/api/episode/${ep_id}/stream?lang=${lang}`);
    stopHls();
    const v = videoEl();
    document.getElementById("player").replaceChildren(v);
    if (!window.Hls || !Hls.isSupported()) throw new Error("HLS not supported in this browser");
    hls = new Hls();
    hls.on(Hls.Events.ERROR, (_, data) => {
      if (data.fatal) {
        showStreamError(`${data.type}: ${data.details}` +
          (data.response ? ` (HTTP ${data.response.code})` : ""));
        stopHls();
      }
    });
    hls.loadSource("/stream/" + s.token);
    hls.attachMedia(v);
    currentEp = {ep_id, ep_no, v};
    lastSavedPos = 0;
    const saved = history.find(x => x.slug_id === detail.slug_id && x.ep_id === ep_id);
    if (saved?.pos > 10) {
      v.addEventListener("loadedmetadata", () => {
        if (saved.pos < v.duration * 0.95) v.currentTime = saved.pos;
      }, {once: true});
    }
    v.onerror = () => showStreamError("media error: " + (v.error?.message || v.error?.code));
    v.play().catch(() => showPlayOverlay(v)); // autoplay blocked (no user gesture) -> visible prompt
    watchPos(v);
    postHistory({title: detail.name, slug_id: detail.slug_id, season_id: seasonId,
                 ep_id, lang, ep: ep_no, pos: saved?.pos || 0});
  } catch (e) {
    showStreamError(e.message);
  }
  document.title = `${detail.name} E${ep_no} — ani-web`;
}

function watchPos(v) {
  const save = () => {
    if (!currentEp || v.currentTime <= 3) return;
    lastSavedPos = v.currentTime;
    postHistory({title: detail.name, slug_id: detail.slug_id, season_id: seasonId,
                 ep_id: currentEp.ep_id, lang, ep: currentEp.ep_no, pos: v.currentTime});
  };
  v.addEventListener("timeupdate", () => { if (v.currentTime - lastSavedPos >= 10) save(); });
  v.addEventListener("pause", save);
  window.addEventListener("pagehide", save);
}

function showPlayOverlay(v) {
  const o = el("button", "play-overlay", "▶ click to play");
  o.onclick = () => { v.play(); o.remove(); };
  v.parentElement.append(o);
}

// ---------- boot ----------
(async () => {
  await refreshHistory();
  const p = new URLSearchParams(location.search);
  try {
    if (p.get("q")) await showSearch(p.get("q"));
    else if (p.get("anime")) await showAnime(p.get("anime"), {
      season: p.get("season") ? +p.get("season") : null,
      ep: p.get("ep") ? +p.get("ep") : null,
      lang: p.get("lang") || "eng",
    });
    else showHome();
  } catch (e) { fail(e); }
})();