(function () {
  const STORAGE_KEY = "rename_mvp_session_id";

  const state = {
    sessionId: initSessionId(),
    selectedSeries: null,
    episodes: [],
    selectedEpisodes: [],
    selectedFiles: [],
    selectedPairIndex: null,
    roots: [],
    modalFolders: [],
    modalFiles: [],
    modalSelectedFilePaths: new Set(),
    syncScrolling: false,
  };

  const el = {
    sessionMeta: document.getElementById("sessionMeta"),
    outputBox: document.getElementById("outputBox"),
    searchInput: document.getElementById("searchInput"),
    searchBtn: document.getElementById("searchBtn"),
    searchResults: document.getElementById("searchResults"),
    seriesInfo: document.getElementById("seriesInfo"),
    refreshEpisodesBtn: document.getElementById("refreshEpisodesBtn"),
    episodesList: document.getElementById("episodesList"),
    episodeMeta: document.getElementById("episodeMeta"),
    refreshSelectedEpisodesBtn: document.getElementById("refreshSelectedEpisodesBtn"),
    clearSelectedEpisodesBtn: document.getElementById("clearSelectedEpisodesBtn"),
    episodeUpBtn: document.getElementById("episodeUpBtn"),
    episodeDownBtn: document.getElementById("episodeDownBtn"),
    episodeRemoveBtn: document.getElementById("episodeRemoveBtn"),
    selectedEpisodesList: document.getElementById("selectedEpisodesList"),
    fileMeta: document.getElementById("fileMeta"),
    selectFilesBtn: document.getElementById("selectFilesBtn"),
    refreshSelectedFilesBtn: document.getElementById("refreshSelectedFilesBtn"),
    clearSelectedFilesBtn: document.getElementById("clearSelectedFilesBtn"),
    fileUpBtn: document.getElementById("fileUpBtn"),
    fileDownBtn: document.getElementById("fileDownBtn"),
    fileRemoveBtn: document.getElementById("fileRemoveBtn"),
    selectedFilesList: document.getElementById("selectedFilesList"),
    filenamePreviewBtn: document.getElementById("filenamePreviewBtn"),
    renameExecuteBtn: document.getElementById("renameExecuteBtn"),
    fileModal: document.getElementById("fileModal"),
    fileModalTitle: document.getElementById("fileModalTitle"),
    closeFileModalBtn: document.getElementById("closeFileModalBtn"),
    modalRootSelect: document.getElementById("modalRootSelect"),
    modalFolderSelect: document.getElementById("modalFolderSelect"),
    modalSubpathInput: document.getElementById("modalSubpathInput"),
    modalRecursiveInput: document.getElementById("modalRecursiveInput"),
    modalLoadFoldersBtn: document.getElementById("modalLoadFoldersBtn"),
    modalLoadFilesBtn: document.getElementById("modalLoadFilesBtn"),
    modalFoldersList: document.getElementById("modalFoldersList"),
    modalFilesList: document.getElementById("modalFilesList"),
    modalAddSelectedFilesBtn: document.getElementById("modalAddSelectedFilesBtn"),
  };

  function initSessionId() {
    const existing = localStorage.getItem(STORAGE_KEY);
    if (existing) return existing;
    const created = "ui-" + Date.now() + "-" + Math.floor(Math.random() * 10000);
    localStorage.setItem(STORAGE_KEY, created);
    return created;
  }

  function q(path) {
    return path.includes("?")
      ? `${path}&session_id=${encodeURIComponent(state.sessionId)}`
      : `${path}?session_id=${encodeURIComponent(state.sessionId)}`;
  }

  async function api(path, options = {}) {
    const resp = await fetch(path, options);
    const text = await resp.text();
    let data = {};
    try {
      data = text ? JSON.parse(text) : {};
    } catch (_err) {
      data = { raw: text };
    }
    if (!resp.ok) {
      throw new Error(data.detail || data.raw || `HTTP ${resp.status}`);
    }
    return data;
  }

  function out(label, payload) {
    el.outputBox.textContent = `${label}\n${JSON.stringify(payload, null, 2)}`;
  }

  function makeBtn(label, handler, secondary) {
    const btn = document.createElement("button");
    btn.textContent = label;
    if (secondary) btn.className = "secondary";
    btn.addEventListener("click", handler);
    return btn;
  }

  function setBusy(btn, busy) {
    if (btn) btn.disabled = busy;
  }

  function updateMeta() {
    const epCount = state.selectedEpisodes.length;
    const fileCount = state.selectedFiles.length;
    const mismatch = epCount !== fileCount;
    const mismatchText = mismatch ? " mismatch" : " aligned";

    el.episodeMeta.innerHTML = `Rows: <b>${epCount}</b>`;
    el.fileMeta.innerHTML = `Rows: <b>${fileCount}</b> <span class="${mismatch ? "mismatch" : ""}">${mismatchText}</span>`;
  }

  function selectPair(index) {
    state.selectedPairIndex = index;
    renderSelectedEpisodes();
    renderSelectedFiles();
  }

  function syncScroll(source, target) {
    if (state.syncScrolling) return;
    state.syncScrolling = true;
    target.scrollTop = source.scrollTop;
    requestAnimationFrame(() => {
      state.syncScrolling = false;
    });
  }

  function renderSelectedEpisodes() {
    el.selectedEpisodesList.innerHTML = "";
    state.selectedEpisodes.forEach((item, idx) => {
      const li = document.createElement("li");
      if (state.selectedPairIndex === idx) li.classList.add("selected");

      const left = document.createElement("span");
      const badge = document.createElement("span");
      badge.className = "badge";
      badge.textContent = `#${idx + 1}`;
      left.appendChild(badge);
      left.appendChild(document.createTextNode(item.episode.label || item.episode.title || "(episode)"));

      const right = document.createElement("div");
      right.appendChild(makeBtn("Select", () => selectPair(idx), true));

      li.appendChild(left);
      li.appendChild(right);
      li.addEventListener("click", () => selectPair(idx));
      el.selectedEpisodesList.appendChild(li);
    });
    updateMeta();
  }

  function renderSelectedFiles() {
    el.selectedFilesList.innerHTML = "";
    state.selectedFiles.forEach((item, idx) => {
      const li = document.createElement("li");
      if (state.selectedPairIndex === idx) li.classList.add("selected");

      const left = document.createElement("span");
      const badge = document.createElement("span");
      badge.className = "badge";
      badge.textContent = `#${idx + 1}`;
      left.appendChild(badge);
      left.appendChild(document.createTextNode(item.file.path || item.file.name || "(file)"));

      const right = document.createElement("div");
      right.appendChild(makeBtn("Select", () => selectPair(idx), true));

      li.appendChild(left);
      li.appendChild(right);
      li.addEventListener("click", () => selectPair(idx));
      el.selectedFilesList.appendChild(li);
    });
    updateMeta();
  }

  async function loadRoots() {
    const data = await api("/api/files/roots");
    state.roots = data.items || [];
    el.modalRootSelect.innerHTML = "";
    state.roots.forEach((root) => {
      const opt = document.createElement("option");
      opt.value = root.id;
      opt.textContent = `${root.id}: ${root.path}`;
      el.modalRootSelect.appendChild(opt);
    });
    if (state.roots.length) {
      el.modalSubpathInput.value = "";
      await loadModalFolders();
    }
  }

  async function doSearch() {
    const query = (el.searchInput.value || "").trim();
    if (!query) return;
    const data = await api(`/api/tvdb/search?q=${encodeURIComponent(query)}`);
    el.searchResults.innerHTML = "";
    (data.items || []).forEach((item) => {
      const li = document.createElement("li");
      const left = document.createElement("span");
      left.textContent = item.display_name || item.name || "(series)";
      const right = document.createElement("div");
      right.appendChild(makeBtn("Select", async () => {
        state.selectedSeries = item;
        el.seriesInfo.textContent = `Selected: ${item.display_name || item.name}`;
        await loadEpisodes();
      }));
      li.appendChild(left);
      li.appendChild(right);
      el.searchResults.appendChild(li);
    });
    out("Search result", data);
  }

  async function loadEpisodes() {
    if (!state.selectedSeries || !state.selectedSeries.id) {
      throw new Error("Select a series first");
    }
    const data = await api(`/api/tvdb/series/${encodeURIComponent(state.selectedSeries.id)}/episodes?order_type=aired`);
    state.episodes = data.items || [];
    el.episodesList.innerHTML = "";
    state.episodes.forEach((episode) => {
      const li = document.createElement("li");
      const left = document.createElement("span");
      left.textContent = episode.label || `${episode.season_number}x${episode.episode_number} ${episode.title}`;
      const right = document.createElement("div");
      right.appendChild(makeBtn("Add", async () => {
        const payload = {
          id: episode.id,
          series: state.selectedSeries.name,
          year: state.selectedSeries.year,
          season_number: episode.season_number,
          episode_number: episode.episode_number,
          title: episode.title,
          aired: episode.aired,
          label: episode.label,
        };
        await api(q("/api/session/selected-episodes"), {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({ items: [payload] }),
        });
        await loadSelectedEpisodes();
      }));
      li.appendChild(left);
      li.appendChild(right);
      el.episodesList.appendChild(li);
    });
    out("Episodes loaded", data);
  }

  async function loadSelectedEpisodes() {
    const data = await api(q("/api/session/selected-episodes"));
    state.selectedEpisodes = data.items || [];
    if (state.selectedPairIndex != null && state.selectedPairIndex >= state.selectedEpisodes.length) {
      state.selectedPairIndex = state.selectedEpisodes.length - 1;
    }
    renderSelectedEpisodes();
    return data;
  }

  async function loadSelectedFiles() {
    const data = await api(q("/api/session/selected-files"));
    state.selectedFiles = data.items || [];
    if (state.selectedPairIndex != null && state.selectedPairIndex >= state.selectedFiles.length) {
      state.selectedPairIndex = state.selectedFiles.length - 1;
    }
    renderSelectedFiles();
    return data;
  }

  function openFileModal() {
    state.modalSelectedFilePaths = new Set();
    el.fileModalTitle.textContent = "File Discovery";
    el.modalAddSelectedFilesBtn.style.display = "";
    el.modalLoadFilesBtn.style.display = "";
    el.fileModal.classList.remove("hidden");
    el.fileModal.setAttribute("aria-hidden", "false");
  }

  function closeFileModal() {
    el.fileModal.classList.add("hidden");
    el.fileModal.setAttribute("aria-hidden", "true");
  }

  async function loadModalFolders() {
    const rootId = el.modalRootSelect.value;
    if (!rootId) throw new Error("No root selected");
    const subpath = (el.modalSubpathInput.value || "").trim();
    const data = await api(
      `/api/files/folders?root_id=${encodeURIComponent(rootId)}&subpath=${encodeURIComponent(subpath)}&limit=5000`
    );
    state.modalFolders = data.items || [];

    el.modalFolderSelect.innerHTML = "";
    const placeholder = document.createElement("option");
    placeholder.value = "";
    placeholder.textContent = state.modalFolders.length ? "Choose folder..." : "(No folders)";
    el.modalFolderSelect.appendChild(placeholder);

    el.modalFoldersList.innerHTML = "";
    state.modalFolders.forEach((folder) => {
      const opt = document.createElement("option");
      opt.value = folder.subpath;
      opt.textContent = folder.subpath || folder.name;
      el.modalFolderSelect.appendChild(opt);

      const li = document.createElement("li");
      const left = document.createElement("span");
      left.textContent = folder.subpath || folder.name;
      const right = document.createElement("div");
      right.appendChild(makeBtn("Select", () => {
        el.modalFolderSelect.value = folder.subpath;
        el.modalSubpathInput.value = folder.subpath;
      }, true));
      li.appendChild(left);
      li.appendChild(right);
      el.modalFoldersList.appendChild(li);
    });

    out("Folders loaded", data);
  }

  async function loadModalFiles() {
    const rootId = el.modalRootSelect.value;
    const subpath = (el.modalFolderSelect.value || "").trim();
    if (!rootId) throw new Error("No root selected");
    if (!subpath) throw new Error("Choose a folder first");

    el.modalSubpathInput.value = subpath;
    const recursive = el.modalRecursiveInput.checked ? "true" : "false";
    const data = await api(
      `/api/files/discover?root_id=${encodeURIComponent(rootId)}&subpath=${encodeURIComponent(subpath)}&recursive=${recursive}&limit=200`
    );
    state.modalFiles = data.items || [];
    el.modalFilesList.innerHTML = "";
    state.modalSelectedFilePaths = new Set();

    state.modalFiles.forEach((file) => {
      const li = document.createElement("li");
      const left = document.createElement("span");
      left.textContent = file.relative_path || file.name;
      const right = document.createElement("div");
      right.appendChild(makeBtn("Toggle", () => {
        if (state.modalSelectedFilePaths.has(file.path)) {
          state.modalSelectedFilePaths.delete(file.path);
          li.classList.remove("selected");
        } else {
          state.modalSelectedFilePaths.add(file.path);
          li.classList.add("selected");
        }
      }, true));
      li.appendChild(left);
      li.appendChild(right);
      el.modalFilesList.appendChild(li);
    });

    out("Discovered files", data);
  }

  async function addModalSelectedFiles() {
    const selected = state.modalFiles.filter((f) => state.modalSelectedFilePaths.has(f.path));
    if (!selected.length) throw new Error("Select at least one file");
    const payload = selected.map((f) => ({ path: f.path, name: f.name }));
    await api(q("/api/session/selected-files"), {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ items: payload }),
    });
    await loadSelectedFiles();
    closeFileModal();
  }

  async function reorderSelectedEpisodes(delta) {
    if (state.selectedPairIndex == null) throw new Error("Select an episode row first");
    const from = state.selectedPairIndex;
    const to = from + delta;
    if (to < 0 || to >= state.selectedEpisodes.length) return;
    await api(q("/api/session/selected-episodes/reorder"), {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ from_index: from, to_index: to }),
    });
    state.selectedPairIndex = to;
    await loadSelectedEpisodes();
  }

  async function reorderSelectedFiles(delta) {
    if (state.selectedPairIndex == null) throw new Error("Select a file row first");
    const from = state.selectedPairIndex;
    const to = from + delta;
    if (to < 0 || to >= state.selectedFiles.length) return;
    await api(q("/api/session/selected-files/reorder"), {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ from_index: from, to_index: to }),
    });
    state.selectedPairIndex = to;
    await loadSelectedFiles();
  }

  async function removeSelectedEpisode() {
    if (state.selectedPairIndex == null) throw new Error("Select an episode row first");
    const item = state.selectedEpisodes[state.selectedPairIndex];
    if (!item) return;
    await api(q(`/api/session/selected-episodes/${item.selection_id}`), { method: "DELETE" });
    await loadSelectedEpisodes();
  }

  async function removeSelectedFile() {
    if (state.selectedPairIndex == null) throw new Error("Select a file row first");
    const item = state.selectedFiles[state.selectedPairIndex];
    if (!item) return;
    await api(q(`/api/session/selected-files/${item.selection_id}`), { method: "DELETE" });
    await loadSelectedFiles();
  }

  async function executeRename() {
    const data = await api(q("/api/session/rename-execute") + "&confirm=true", { method: "POST" });
    if (data.executed) {
      out("Rename execute: success", data);
      const renamedFiles = (data.items || [])
        .filter((i) => i.status === "renamed")
        .map((i) => ({ path: i.destination_path, name: i.proposed_filename }));
      await api(q("/api/session/selected-files"), { method: "DELETE" });
      if (renamedFiles.length) {
        await api(q("/api/session/selected-files"), {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({ items: renamedFiles }),
        });
      }
      await loadSelectedFiles();
      return;
    }
    out("Rename execute: preflight failed", data);
  }

  async function withHandler(fn, btn) {
    try {
      setBusy(btn, true);
      await fn();
    } catch (err) {
      out("Error", { detail: err.message || String(err) });
    } finally {
      setBusy(btn, false);
    }
  }

  function bindEvents() {
    el.searchBtn.addEventListener("click", () => withHandler(doSearch, el.searchBtn));
    el.refreshEpisodesBtn.addEventListener("click", () => withHandler(loadEpisodes, el.refreshEpisodesBtn));

    el.refreshSelectedEpisodesBtn.addEventListener("click", () => withHandler(loadSelectedEpisodes, el.refreshSelectedEpisodesBtn));
    el.clearSelectedEpisodesBtn.addEventListener("click", () =>
      withHandler(async () => {
        await api(q("/api/session/selected-episodes"), { method: "DELETE" });
        state.selectedPairIndex = null;
        await loadSelectedEpisodes();
      }, el.clearSelectedEpisodesBtn)
    );
    el.episodeUpBtn.addEventListener("click", () => withHandler(() => reorderSelectedEpisodes(-1), el.episodeUpBtn));
    el.episodeDownBtn.addEventListener("click", () => withHandler(() => reorderSelectedEpisodes(1), el.episodeDownBtn));
    el.episodeRemoveBtn.addEventListener("click", () => withHandler(removeSelectedEpisode, el.episodeRemoveBtn));

    el.selectFilesBtn.addEventListener("click", () => withHandler(async () => {
      openFileModal();
      await loadRoots();
    }, el.selectFilesBtn));
    el.refreshSelectedFilesBtn.addEventListener("click", () => withHandler(loadSelectedFiles, el.refreshSelectedFilesBtn));
    el.clearSelectedFilesBtn.addEventListener("click", () =>
      withHandler(async () => {
        await api(q("/api/session/selected-files"), { method: "DELETE" });
        state.selectedPairIndex = null;
        await loadSelectedFiles();
      }, el.clearSelectedFilesBtn)
    );
    el.fileUpBtn.addEventListener("click", () => withHandler(() => reorderSelectedFiles(-1), el.fileUpBtn));
    el.fileDownBtn.addEventListener("click", () => withHandler(() => reorderSelectedFiles(1), el.fileDownBtn));
    el.fileRemoveBtn.addEventListener("click", () => withHandler(removeSelectedFile, el.fileRemoveBtn));

    el.filenamePreviewBtn.addEventListener("click", () => withHandler(async () => out("Filename preview", await api(q("/api/session/filename-preview"))), el.filenamePreviewBtn));
    el.renameExecuteBtn.addEventListener("click", () => withHandler(executeRename, el.renameExecuteBtn));

    el.closeFileModalBtn.addEventListener("click", closeFileModal);
    el.fileModal.addEventListener("click", (e) => {
      if (e.target === el.fileModal) closeFileModal();
    });
    el.modalRootSelect.addEventListener("change", () => withHandler(loadModalFolders, el.modalRootSelect));
    el.modalLoadFoldersBtn.addEventListener("click", () => withHandler(loadModalFolders, el.modalLoadFoldersBtn));
    el.modalLoadFilesBtn.addEventListener("click", () => withHandler(loadModalFiles, el.modalLoadFilesBtn));
    el.modalFolderSelect.addEventListener("change", () => {
      const sub = (el.modalFolderSelect.value || "").trim();
      if (sub) el.modalSubpathInput.value = sub;
    });
    el.modalAddSelectedFilesBtn.addEventListener("click", () => withHandler(addModalSelectedFiles, el.modalAddSelectedFilesBtn));

    el.selectedEpisodesList.addEventListener("scroll", () => syncScroll(el.selectedEpisodesList, el.selectedFilesList));
    el.selectedFilesList.addEventListener("scroll", () => syncScroll(el.selectedFilesList, el.selectedEpisodesList));
  }

  async function init() {
    el.sessionMeta.textContent = `session_id: ${state.sessionId}`;
    el.modalRecursiveInput.checked = true;
    bindEvents();
    await loadSelectedEpisodes();
    await loadSelectedFiles();
    await loadRoots();
  }

  init().catch((err) => out("Init error", { detail: err.message || String(err) }));
})();