(() => {
  const defaults = {
    rootSelector: "",
    contentSelector: "",
    fragmentSelector: "",
    statusTextSelector: "",
    tabSelector: "",
    panelSelector: "",
    selectSelector: "",
    tabDataKey: "",
    panelDataKey: "",
    storageKey: "",
    defaultTab: "",
    defaultEndpoint: "",
    source: "WritingMode",
    allowChapterOnly: false,
    waitingStatus: "Connected, waiting for scene",
    updatingStatus: "Updating",
    disconnectedStatus: "Word not connected"
  };

  const parsePositiveInt = (value) => {
    const parsed = Number.parseInt(value || "", 10);
    return Number.isInteger(parsed) && parsed > 0 ? parsed : null;
  };

  const initialize = (options) => {
    const config = { ...defaults, ...options };
    const root = document.querySelector(config.rootSelector);
    if (!root) {
      return null;
    }

    const contentHost = root.querySelector(config.contentSelector);
    const statusText = root.querySelector(config.statusTextSelector);
    const endpoint = root.dataset.contextUrl || config.defaultEndpoint;
    const scopedProjectId = parsePositiveInt(root.dataset.scopeProjectId);
    const scopedBookId = parsePositiveInt(root.dataset.scopeBookId);
    let currentFragment = contentHost?.querySelector(config.fragmentSelector);
    let currentSceneId = parsePositiveInt(currentFragment?.dataset.sceneId);
    let currentChapterId = parsePositiveInt(currentFragment?.dataset.chapterId);
    let loadingSceneId = null;
    let loadingChapterId = null;

    const setStatus = (value) => {
      if (statusText && value) {
        statusText.textContent = value;
      }
    };

    const registerWorkspaceRole = () => {
      const role = config.source === "WritingContext"
        ? window.PlotDirectorWritingWorkspace?.roles?.context
        : config.source === "WritingIntent"
          ? window.PlotDirectorWritingWorkspace?.roles?.intent
          : null;
      if (!role || !window.PlotDirectorWritingWorkspace?.registerWindow) {
        return;
      }

      const fragment = contentHost?.querySelector(config.fragmentSelector);
      void window.PlotDirectorWritingWorkspace.registerWindow({
        projectID: fragment?.dataset.projectId || root.dataset.scopeProjectId,
        bookID: fragment?.dataset.bookId || root.dataset.scopeBookId,
        writingRole: role,
        displayLabel: config.source === "WritingContext" ? "Writing Context" : "Writing Intent"
      }).catch(() => null);
    };

    const readStoredTab = () => {
      try {
        return localStorage.getItem(config.storageKey) || config.defaultTab;
      } catch {
        return config.defaultTab;
      }
    };

    const activeTab = () => {
      const active = contentHost?.querySelector(`${config.tabSelector}.active`)?.dataset[config.tabDataKey];
      return active || readStoredTab();
    };

    const activateTab = (tabName) => {
      const nextTab = tabName || config.defaultTab;
      contentHost?.querySelectorAll(config.tabSelector).forEach((button) => {
        const active = button.dataset[config.tabDataKey] === nextTab;
        button.classList.toggle("active", active);
        button.setAttribute("aria-selected", String(active));
      });
      contentHost?.querySelectorAll(config.panelSelector).forEach((panel) => {
        const active = panel.dataset[config.panelDataKey] === nextTab;
        panel.classList.toggle("active", active);
        panel.hidden = !active;
      });
      try {
        localStorage.setItem(config.storageKey, nextTab);
      } catch {
        // Remembering the selected tab is a convenience only.
      }
    };

    const wireFragment = () => {
      activateTab(activeTab());
      const fragment = contentHost?.querySelector(config.fragmentSelector);
      const fragmentStatus = fragment?.dataset.followStatus;
      if (fragmentStatus) {
        setStatus(fragmentStatus);
      }
      registerWorkspaceRole();

      const fragmentSceneId = parsePositiveInt(fragment?.dataset.sceneId);
      if (fragmentSceneId) {
        currentSceneId = fragmentSceneId;
      }

      const fragmentChapterId = parsePositiveInt(fragment?.dataset.chapterId);
      if (fragmentChapterId) {
        currentChapterId = fragmentChapterId;
      }

      contentHost?.querySelectorAll(config.tabSelector).forEach((button) => {
        button.addEventListener("click", () => activateTab(button.dataset[config.tabDataKey]));
      });

      contentHost?.querySelector(config.selectSelector)?.addEventListener("change", (event) => {
        const sceneId = parsePositiveInt(event.target.value);
        if (!sceneId) {
          return;
        }

        const fragment = contentHost?.querySelector(config.fragmentSelector);
        window.PlotDirectorStoryPosition?.publishChanged({
          source: config.source,
          projectId: fragment?.dataset.projectId,
          bookId: fragment?.dataset.bookId,
          chapterId: fragment?.dataset.chapterId,
          sceneId
        }, config.source);
      });

      contentHost?.querySelector("[data-writing-intent-chapter-select]")?.addEventListener("change", (event) => {
        const chapterId = parsePositiveInt(event.target.value);
        if (!chapterId) {
          return;
        }

        const fragment = contentHost?.querySelector(config.fragmentSelector);
        window.PlotDirectorStoryPosition?.publishChanged({
          source: config.source,
          projectId: fragment?.dataset.projectId,
          bookId: fragment?.dataset.bookId,
          chapterId
        }, config.source);
      });
    };

    const inScope = (position) => {
      if (scopedProjectId && position.projectId !== scopedProjectId) {
        return false;
      }

      if (scopedBookId && position.bookId && position.bookId !== scopedBookId) {
        return false;
      }

      return true;
    };

    const loadPosition = async (position) => {
      const hasScene = Number.isInteger(position?.sceneId) && position.sceneId > 0;
      const hasChapter = Number.isInteger(position?.chapterId) && position.chapterId > 0;
      if (!position || !inScope(position) || (!hasScene && (!config.allowChapterOnly || !hasChapter))) {
        return;
      }

      if (hasScene && (position.sceneId === currentSceneId || position.sceneId === loadingSceneId)) {
        return;
      }

      if (!hasScene && (position.chapterId === currentChapterId || position.chapterId === loadingChapterId)) {
        return;
      }

      const tab = activeTab();
      loadingSceneId = hasScene ? position.sceneId : null;
      loadingChapterId = !hasScene ? position.chapterId : null;
      setStatus(config.updatingStatus);
      const url = new URL(endpoint, window.location.origin);
      if (position.projectId) url.searchParams.set("projectId", position.projectId);
      if (position.bookId) url.searchParams.set("bookId", position.bookId);
      if (position.chapterId) url.searchParams.set("chapterId", position.chapterId);
      if (hasScene) url.searchParams.set("sceneId", position.sceneId);

      try {
        const response = await fetch(url, { headers: { "X-Requested-With": "XMLHttpRequest" } });
        if (!response.ok) {
          throw new Error(`${config.source} request failed: ${response.status}`);
        }

        contentHost.innerHTML = await response.text();
        if (hasScene) {
          currentSceneId = position.sceneId;
        }
        if (hasChapter) {
          currentChapterId = position.chapterId;
        }
        wireFragment();
        activateTab(tab);
      } catch (error) {
        console.debug(`${config.source} could not update.`, error);
        setStatus(config.waitingStatus);
      } finally {
        loadingSceneId = null;
        loadingChapterId = null;
      }
    };

    document.addEventListener(window.PlotDirectorStoryPosition?.eventName || "plotdirector:story-position-changed", (event) => {
      void loadPosition(event.detail);
    });

    if (window.signalR) {
      const connection = new signalR.HubConnectionBuilder()
        .withUrl("/hubs/word-companion-follow")
        .withAutomaticReconnect()
        .build();

      connection.on("storyPositionChanged", (payload) => {
        window.PlotDirectorStoryPosition?.publishChanged(payload, payload?.source || payload?.Source || "WordCompanion");
      });

      connection.start()
        .then(() => {
          if (!currentSceneId) {
            setStatus(config.waitingStatus);
          }
        })
        .catch((error) => {
          console.debug(`${config.source} follow connection unavailable.`, error);
          setStatus(config.disconnectedStatus);
        });
    } else {
      setStatus(config.disconnectedStatus);
    }

    wireFragment();
    return { loadPosition, activateTab };
  };

  window.PlotDirectorWritingFollow = { initialize };
})();