const state = {
  titles: [],
  activeId: "",
  query: "",
  view: "collection"
};

const els = {
  libraryBadge: document.querySelector("#libraryBadge"),
  backBtn: document.querySelector("#backBtn"),
  rescanBtn: document.querySelector("#rescanBtn"),
  searchInput: document.querySelector("#searchInput"),
  details: document.querySelector("#details"),
  titleCardTemplate: document.querySelector("#titleCardTemplate"),
  playerOverlay: document.querySelector("#playerOverlay"),
  playerVideo: document.querySelector("#playerVideo"),
  closePlayerBtn: document.querySelector("#closePlayerBtn"),
  playerNowPlaying: document.querySelector("#playerNowPlaying")
};

const player = {
  playlist: [],
  index: 0
};

function bytes(value) {
  const units = ["B", "KB", "MB", "GB", "TB"];
  let size = value;
  let unit = 0;
  while (size >= 1024 && unit < units.length - 1) {
    size /= 1024;
    unit += 1;
  }
  return `${size.toFixed(size >= 10 || unit === 0 ? 0 : 1)} ${units[unit]}`;
}

async function api(path, options = {}) {
  const response = await fetch(path, {
    headers: { "content-type": "application/json" },
    ...options
  });
  const data = await response.json();
  if (!response.ok) throw new Error(data.error || "Request failed");
  return data;
}

async function loadLibrary() {
  const data = await api("/api/library");
  state.titles = data.titles;
  els.libraryBadge.textContent = `${state.titles.length} title${state.titles.length === 1 ? "" : "s"}`;
  if (!state.titles.some((title) => title.id === state.activeId)) {
    state.activeId = "";
    state.view = "collection";
  }
  render();
}

function filteredTitles() {
  const query = state.query.toLowerCase();
  if (!query) return state.titles;
  return state.titles.filter((title) => {
    return [
      title.title,
      title.folder,
      title.description,
      ...title.videos.map((video) => video.relativePath)
    ].join(" ").toLowerCase().includes(query);
  });
}

function render() {
  const activeTitle = state.titles.find((item) => item.id === state.activeId);
  els.backBtn.classList.toggle("hidden", state.view !== "details");
  if (state.view === "details" && activeTitle) {
    renderDetails(activeTitle);
    return;
  }
  renderCollection();
}

function renderCollection() {
  const titles = filteredTitles();
  if (!titles.length) {
    els.details.innerHTML = `
      <div class="empty">
        <h2>No titles found</h2>
        <p>Expected: Library/&lt;Movie or Series&gt;/filename.mp4 or Library/&lt;Series&gt;/Season 01/filename.mp4</p>
      </div>
    `;
    return;
  }

  els.details.innerHTML = `
    <div class="collection-grid" id="collectionGrid"></div>
  `;

  const grid = document.querySelector("#collectionGrid");
  for (const title of titles) {
    const node = els.titleCardTemplate.content.firstElementChild.cloneNode(true);
    node.querySelector(".title-card__name").textContent = title.title;
    node.querySelector(".title-card__meta").textContent = `${title.count} file${title.count === 1 ? "" : "s"} · ${bytes(title.size)}`;
    node.querySelector(".title-card__fallback").textContent = initials(title.title);
    const poster = node.querySelector(".title-card__poster");
    const image = node.querySelector("img");
    if (title.thumbnail) {
      poster.classList.add("has-image");
      image.src = title.thumbnail;
      image.alt = "";
    }
    node.addEventListener("click", () => {
      state.activeId = title.id;
      state.view = "details";
      render();
    });
    grid.append(node);
  }
}

function renderDetails(title) {
  els.details.innerHTML = `
    <div class="hero">
      <div class="poster">${title.thumbnail ? `<img src="${escapeAttr(title.thumbnail)}" alt="">` : `<span>${initials(title.title)}</span>`}</div>
      <div class="summary">
        <div class="summary__header">
          <div>
            <h2>${escapeHtml(title.title)}</h2>
            <p>${escapeHtml(title.folder)} · ${title.count} file${title.count === 1 ? "" : "s"} · ${bytes(title.size)}</p>
          </div>
          <div class="summary__actions">
            <button id="editMetaBtn" type="button">Edit</button>
            <button id="fetchMetadataBtn" type="button">Metadata</button>
            <button id="makeThumbBtn" type="button">Thumbnail</button>
            <button id="playAllBtn" class="primary" type="button">Play all</button>
          </div>
        </div>
        <div id="metaView" class="meta-view">
          <section>
            <span>Description</span>
            <p>${title.description ? escapeHtml(title.description) : "No description yet"}</p>
          </section>
        </div>
        <div id="metaEditMount"></div>
      </div>
    </div>
    <div class="seasons">
      ${title.seasons.map(renderSeason).join("")}
    </div>
  `;

  wireEpisodeCards(title);

  document.querySelector("#editMetaBtn").addEventListener("click", () => {
    renderMetadataForm(title);
  });

  document.querySelector("#playAllBtn").addEventListener("click", () => {
    startPlaylist(flattenVideos(title), 0);
  });

  document.querySelector("#makeThumbBtn").addEventListener("click", async (event) => {
    event.currentTarget.disabled = true;
    event.currentTarget.textContent = "Working";
    try {
      await api(`/api/titles/${encodeURIComponent(title.id)}/thumbnail`, { method: "POST", body: "{}" });
      await loadLibrary();
    } catch (err) {
      alert(err.message);
      event.currentTarget.disabled = false;
      event.currentTarget.textContent = "Thumbnail";
    }
  });

  document.querySelector("#fetchMetadataBtn").addEventListener("click", async (event) => {
    event.currentTarget.disabled = true;
    event.currentTarget.textContent = "Fetching";
    try {
      await api(`/api/titles/${encodeURIComponent(title.id)}/metadata`, { method: "POST", body: "{}" });
      await loadLibrary();
    } catch (err) {
      alert(err.message);
      event.currentTarget.disabled = false;
      event.currentTarget.textContent = "Metadata";
    }
  });
}

function renderMetadataForm(title) {
  document.querySelector("#metaView").classList.add("hidden");
  const mount = document.querySelector("#metaEditMount");
  mount.innerHTML = `
    <form id="metaForm" class="meta-form">
      <label>
        <span>Display title</span>
        <input name="title" value="${escapeAttr(title.title)}">
      </label>
      <label>
        <span>Thumbnail path or URL</span>
        <input name="thumbnail" value="${escapeAttr(title.thumbnail)}" placeholder="/thumbs/example.jpg">
      </label>
      <label>
        <span>Short description</span>
        <textarea name="description" rows="5" placeholder="Add a private note or synopsis">${escapeHtml(title.description)}</textarea>
      </label>
      <div class="meta-form__actions">
        <button class="primary" type="submit">Save metadata</button>
        <button id="cancelMetaBtn" class="ghost" type="button">Cancel</button>
      </div>
    </form>
  `;

  document.querySelector("#cancelMetaBtn").addEventListener("click", () => {
    mount.innerHTML = "";
    document.querySelector("#metaView").classList.remove("hidden");
  });

  document.querySelector("#metaForm").addEventListener("submit", async (event) => {
    event.preventDefault();
    const form = new FormData(event.currentTarget);
    await api(`/api/titles/${encodeURIComponent(title.id)}`, {
      method: "PATCH",
      body: JSON.stringify({
        title: form.get("title"),
        thumbnail: form.get("thumbnail"),
        description: form.get("description")
      })
    });
    await loadLibrary();
  });
}

function renderSeason(season) {
  return `
    <section class="season">
      <h3>${escapeHtml(season.name)}</h3>
      <div class="episodes">
        ${season.videos.map((video) => `
          <button class="episode" type="button" data-video-id="${escapeAttr(video.id)}">
            <span class="episode__thumb">
              <img src="${escapeAttr(video.thumbnail)}" alt="" loading="lazy" onerror="this.hidden=true">
              <span class="episode__play">Play</span>
            </span>
            <span class="episode__name">${escapeHtml(video.name)}</span>
            <span class="episode__meta">${escapeHtml(video.relativePath)} · ${bytes(video.size)}</span>
          </button>
        `).join("")}
      </div>
    </section>
  `;
}

function flattenVideos(title) {
  return title.seasons.flatMap((season) => season.videos);
}

function wireEpisodeCards(title) {
  const videos = flattenVideos(title);
  document.querySelectorAll("[data-video-id]").forEach((node) => {
    node.addEventListener("click", () => {
      const index = videos.findIndex((video) => video.id === node.dataset.videoId);
      startPlaylist(videos, Math.max(index, 0));
    });
  });
}

function startPlaylist(videos, index = 0) {
  if (!videos.length) return;
  player.playlist = videos;
  player.index = index;
  els.playerOverlay.classList.remove("hidden");
  playCurrent();
  const fullscreenTarget = els.playerOverlay;
  if (fullscreenTarget.requestFullscreen) {
    fullscreenTarget.requestFullscreen().catch(() => {});
  }
}

function playCurrent() {
  const video = player.playlist[player.index];
  if (!video) {
    closePlayer();
    return;
  }
  els.playerVideo.src = `/video/${encodeURIComponent(video.id)}`;
  els.playerNowPlaying.textContent = `${video.name} · ${player.index + 1} / ${player.playlist.length}`;
  els.playerVideo.play().catch(() => {});
}

function closePlayer() {
  els.playerVideo.pause();
  els.playerVideo.removeAttribute("src");
  els.playerVideo.load();
  els.playerOverlay.classList.add("hidden");
  if (document.fullscreenElement) document.exitFullscreen().catch(() => {});
}

function initials(value) {
  return value.split(/\s+/).slice(0, 2).map((part) => part[0] || "").join("").toUpperCase();
}

function escapeHtml(value) {
  return String(value).replace(/[&<>"']/g, (char) => ({
    "&": "&amp;",
    "<": "&lt;",
    ">": "&gt;",
    '"': "&quot;",
    "'": "&#39;"
  })[char]);
}

function escapeAttr(value) {
  return escapeHtml(value).replace(/`/g, "&#96;");
}

els.searchInput.addEventListener("input", (event) => {
  state.query = event.target.value;
  state.view = "collection";
  render();
});

els.backBtn.addEventListener("click", () => {
  state.view = "collection";
  render();
});

els.closePlayerBtn.addEventListener("click", closePlayer);

els.playerVideo.addEventListener("ended", () => {
  player.index += 1;
  playCurrent();
});

document.addEventListener("fullscreenchange", () => {
  if (!document.fullscreenElement && !els.playerOverlay.classList.contains("hidden")) {
    closePlayer();
  }
});

els.rescanBtn.addEventListener("click", async () => {
  els.rescanBtn.disabled = true;
  els.rescanBtn.textContent = "Scanning";
  try {
    await api("/api/rescan", { method: "POST", body: "{}" });
    await loadLibrary();
  } finally {
    els.rescanBtn.disabled = false;
    els.rescanBtn.textContent = "Rescan";
  }
});

loadLibrary().catch((err) => {
  els.details.innerHTML = `<div class="empty"><h2>Could not load library</h2><p>${escapeHtml(err.message)}</p></div>`;
});