import type {
  CompletionContext,
  CompletionResult,
} from "@codemirror/autocomplete";
import { history } from "@codemirror/commands";
import { syntaxTree } from "@codemirror/language";
import type { Compartment, EditorState } from "@codemirror/state";
import { EditorView } from "@codemirror/view";
import type { SyntaxNode } from "@lezer/common";
import { jitter } from "@silverbulletmd/silverbullet/lib/async";
import { deriveDbName } from "@silverbulletmd/silverbullet/lib/crypto";
import {
  encodePageURI,
  encodeRef,
  getNameFromPath,
  isMarkdownPath,
  type Path,
  parseToRef,
  type Ref,
} from "@silverbulletmd/silverbullet/lib/ref";
import type {
  AppEvent,
  ClickEvent,
  CompleteEvent,
  EnrichedClickEvent,
  SlashCompletions,
} from "@silverbulletmd/silverbullet/type/client";
import type {
  DocumentMeta,
  FileMeta,
  PageMeta,
} from "@silverbulletmd/silverbullet/type/index";
import type { StyleObject } from "../plugs/index/space_style.ts";
import type { ResolveAnchorResult } from "../plugs/index/types.ts";
import { version as publicVersion } from "../version.json";
import { ClientSystem } from "./client_system.ts";
import {
  buildMarkdownLanguageExtension,
  createEditorState,
  isValidEditor,
} from "./codemirror/editor_state.ts";
import { withCompletionInfo } from "./codemirror/completion_info.ts";
import type { Config } from "./config.ts";
import { ContentManager } from "./content_manager.ts";
import { Augmenter } from "./data/data_augmenter.ts";
import { DataStore } from "./data/datastore.ts";
import { EncryptedKvPrimitives } from "./data/encrypted_kv_primitives.ts";
import { IndexedDBKvPrimitives } from "./data/indexeddb_kv_primitives.ts";
import type { KvPrimitives } from "./data/kv_primitives.ts";
import { DataStoreMQ } from "./data/mq.datastore.ts";
import { ObjectIndex } from "./data/object_index.ts";
import { MainUI } from "./editor_ui.tsx";
import { PathPageNavigator, parseRefFromURI } from "./navigator.ts";
import { EventHook } from "./plugos/hooks/event.ts";
import { RealtimeEvents } from "./realtime_events.ts";
import { reloadWithUpdatedServiceWorker } from "./service_worker/util.ts";
import { Space } from "./space.ts";
import { evalStatement } from "./space_lua/eval.ts";
import {
  parseExpressionString,
  parseBlock as parseLua,
} from "./space_lua/parse.ts";
import type { LuaCollectionQuery } from "./space_lua/query_collection.ts";
import {
  LuaEnv,
  LuaRuntimeError,
  LuaStackFrame,
  luaValueToJS,
} from "./space_lua/runtime.ts";
import { resolveASTReference } from "./space_lua.ts";
import { CheckedSpacePrimitives } from "./spaces/checked_space_primitives.ts";
import { fsEndpoint } from "./spaces/constants.ts";
import { EventedSpacePrimitives } from "./spaces/evented_space_primitives.ts";
import { HttpSpacePrimitives } from "./spaces/http_space_primitives.ts";
import type { Command } from "./types/command.ts";
import type {
  AppViewState,
  BootConfig,
  ServiceWorkerSourceMessage,
  ServiceWorkerTargetMessage,
} from "./types/ui.ts";
import { WidgetCache } from "./widget_cache.ts";

// Fetch the file list ever so often, this will implicitly kick off a snapshot comparison resulting in the indexing of changed pages
const fetchFileListInterval = 10000;

// Runtime API bridge: written by the client when running headless to evaluate Lua in the live client.
export type SBRuntime = {
  headless?: boolean;
  ready?: boolean;
  evalLua?: (expr: string) => Promise<unknown>;
  evalLuaScript?: (script: string) => Promise<unknown>;
};

declare global {
  var client: Client;
  var sbRuntime: SBRuntime;
}

// TODO: Clean this up, this has become a god class...
export class Client {
  // Event bus used to communicate between components
  eventHook: EventHook;

  space!: Space;

  clientSystem!: ClientSystem;
  eventedSpacePrimitives!: EventedSpacePrimitives;
  httpSpacePrimitives!: HttpSpacePrimitives;
  realtimeEvents?: RealtimeEvents;

  ui!: MainUI;
  ds!: DataStore;
  mq!: DataStoreMQ;
  // Used to store additional pageMeta outside the page index itself persistent between client runs (specifically: lastOpened)
  pageMetaAugmenter!: Augmenter;
  // Used to store additional command data outside the objects themselves persistent between client rusn (specifically: lastRun)
  commandAugmenter!: Augmenter;

  // CodeMirror editor
  editorView!: EditorView;
  commandKeyHandlerCompartment?: Compartment;
  vimCompartment?: Compartment;
  indentUnitCompartment?: Compartment;
  undoHistoryCompartment?: Compartment;
  markdownLanguageCompartment?: Compartment;

  // Content manager: handles page/document loading, saving, and editor mode switching
  contentManager!: ContentManager;
  // Track if plugs have been updated since sync cycle
  fullSyncCompleted = false;
  private versionMismatchNotified = false;
  // True once we've confirmed the server reports the same publicVersion as
  // this client bundle and the plugs the server is shipping are aligned with the running build.
  private versionsInSync = false;

  // Set to true once the system is ready (plugs loaded)
  public systemReady: boolean = false;
  // Set to true once the object index has been fully built at least once
  public fullIndexCompleted: boolean = false;
  // Set to true once viewState.allPages has been populated from the index
  public pageListLoaded: boolean = false;
  // Guard so we only fire the loading→ready editor:reloadState once.
  private widgetReadyDispatched: boolean = false;
  // Resolves once the widget-ready transition has been dispatched and the
  // resulting editor state rebuild has settled. Headless tests wait on
  // this to avoid typing into the editor mid-rebuild.
  public widgetsReady!: Promise<void>;
  private resolveWidgetsReady!: () => void;
  private pageNavigator!: PathPageNavigator;
  private onLoadRef: Ref;
  dbPrefix?: string;
  syncMode = false;
  // Widget and image height caching
  widgetCache!: WidgetCache;
  objectIndex!: ObjectIndex;

  constructor(
    private parent: Element,
    public bootConfig: BootConfig,
    readonly config: Config,
  ) {
    this.eventHook = new EventHook(this.config);
    // The third case should only ever happen when the user provides an invalid index env variable
    this.onLoadRef = parseRefFromURI() || this.getIndexRef();
    this.widgetsReady = new Promise<void>((resolve) => {
      this.resolveWidgetsReady = resolve;
    });
  }

  /**
   * Initialize the client
   * This is a separated from the constructor to allow for async initialization
   */
  async init(encryptionKey?: CryptoKey) {
    const dbName = await deriveDbName(
      "data",
      this.bootConfig.spaceFolderPath,
      document.baseURI.replace(/\/$/, ""),
      encryptionKey,
    );
    // Setup the KV (database)
    let kvPrimitives: KvPrimitives = new IndexedDBKvPrimitives(dbName);
    await (kvPrimitives as IndexedDBKvPrimitives).init();

    console.log("Using IndexedDB database", dbName);

    // See if we need to encrypt this
    if (encryptionKey) {
      kvPrimitives = new EncryptedKvPrimitives(kvPrimitives, encryptionKey);
      await (kvPrimitives as EncryptedKvPrimitives).init();
      console.log("Enabled client-side encryption");
    }
    // Wrap it in a datastore
    this.ds = new DataStore(kvPrimitives);

    this.pageMetaAugmenter = new Augmenter(this.ds, ["aug", "pageMeta"]);
    this.commandAugmenter = new Augmenter(this.ds, ["aug", "command"]);

    // Setup message queue on top of that
    this.mq = new DataStoreMQ(this.ds, this.eventHook);

    this.widgetCache = new WidgetCache(this.ds);
    this.contentManager = new ContentManager(this);

    this.objectIndex = new ObjectIndex(
      this.ds,
      this.config,
      this.eventHook,
      this.mq,
    );

    // Seed the full-index readiness flag from persistent state so a
    // warm reload doesn't unnecessarily flash loading spinners. A stale
    // stored version (older than `desiredIndexVersion`) still counts as
    // ready: the entries are queryable while `ensureFullIndex` waits for
    // sync + version confirmation. See `ObjectIndex.isIndexAvailable`.
    this.fullIndexCompleted = await this.objectIndex.isIndexAvailable();

    // After the initial index completes (object_index.ts dispatches this),
    // mark the flag and — if the page list cache previously took the
    // fallback branch (so `pageListLoaded` stayed false) — re-run it
    // so it reflects the now-indexed, transform-applied values. The
    // editor itself will be rebuilt by client_system's listener for
    // the same event; we don't need to dispatch a fresh one here.
    this.eventHook.addLocalListener("editor:reloadState", () => {
      this.fullIndexCompleted = true;
      if (!this.pageListLoaded) {
        this.updatePageListCache().catch(console.error);
      }
    });

    // If widget rendering is still gated waiting on a full index, the
    // initial-index handler in ObjectIndex may have unsubscribed or
    // never fired for this client. After any indexing pass empties the
    // queue, refresh the page list cache so its index-backed branch
    // can flip pageListLoaded and unblock widget rendering.
    this.eventHook.addLocalListener("mq:emptyQueue:indexQueue", async () => {
      if (this.widgetReadyDispatched) return;
      if (
        !this.pageListLoaded &&
        (await this.objectIndex.hasFullIndexCompleted())
      ) {
        this.fullIndexCompleted = true;
        await this.updatePageListCache();
      }
    });

    // Instantiate a PlugOS system
    this.clientSystem = new ClientSystem(
      this,
      this.mq,
      this.ds,
      this.eventHook,
      this.objectIndex,
      this.bootConfig.readOnly,
    );

    this.initSpace();

    this.ui = new MainUI(this);
    this.ui.render(this.parent);

    this.editorView = new EditorView({
      state: createEditorState(this, "", "", true),
      parent: document.getElementById("sb-editor")!,
    });

    this.focus();

    this.clientSystem.init();

    if (this.bootConfig.performWipe) {
      if (confirm("Are you sure you want to wipe the client?")) {
        await this.wipeClient();
        alert("Wipe done. Please reload the page or navigate away.");
        return;
      }
    }
    if (this.bootConfig.performReset) {
      if (
        confirm(
          "Are you sure you want to reset the client? This will wipe all local data and re-sync everything.",
        )
      ) {
        await this.wipeClient();
        location.reload();
        return;
      }
    }

    await this.widgetCache.load();

    // Let's ping the remote space to ensure we're authenticated properly, if not will result in a redirect to auth page
    try {
      await this.httpSpacePrimitives.ping();
    } catch (e: any) {
      if (e.message === "Not authenticated") {
        console.warn("Not authenticated, redirecting to auth page");
        return;
      }
      console.warn(
        "Could not reach remote server, we're offline or the server is down",
        e,
      );
    }

    // Load plugs
    await this.loadPlugs();

    await this.clientSystem.loadLuaScripts();
    await this.initNavigator();
    // await this.initSync();
    await this.eventHook.dispatchEvent("system:ready");
    this.systemReady = true;
    this.maybeDispatchWidgetsReady();

    // When the service worker is disabled (desktop app / headless) there's no
    // SW proxy performing the `server-version` handshake that normally sets
    // `versionsInSync`. The bundled client and server are a matching set, so
    // treat versions as in sync. This both lets us check the index immediately
    // AND lets `space-sync-complete` signals — bridged in from the native sync
    // engine — drive the version-bump reindex after each sync cycle (otherwise
    // the gate in `handleServiceWorkerMessage` would stay permanently closed).
    if (this.bootConfig.disableServiceWorker) {
      this.versionsInSync = true;
      void this.objectIndex.ensureFullIndex(this.space);
    }

    this.initHeadlessRuntime();

    // Load space snapshot and enable events
    await this.eventedSpacePrimitives.enable();

    // Kick off a cron event interval
    setInterval(() => {
      void this.dispatchAppEvent("cron:secondPassed");
    }, 1000);

    // We can load custom styles async
    this.loadCustomStyles().catch(console.error);

    await this.dispatchAppEvent("editor:init");

    // Reset Undo History after editor initialization.
    client.editorView.dispatch({
      effects: client.undoHistoryCompartment?.reconfigure([]),
    });
    client.editorView.dispatch({
      effects: client.undoHistoryCompartment?.reconfigure([history()]),
    });

    // Asynchronously update caches
    this.updatePageListCache().catch(console.error);
    this.updateDocumentListCache().catch(console.error);
  }

  initSpace() {
    this.httpSpacePrimitives = new HttpSpacePrimitives(
      document.baseURI.replace(/\/*$/, "") + fsEndpoint,
      this.bootConfig.spaceFolderPath,
      (message, actionOrRedirectHeader) => {
        alert(message);
        if (actionOrRedirectHeader === "reload") {
          location.reload();
        } else {
          location.href = actionOrRedirectHeader;
        }
      },
      // Bearer token injected by an embedder (e.g. the Tauri App) as
      // `globalThis.silverbullet.bearerToken` before the bundle loads.
      // Undefined in a normal browser deployment, which leaves
      // HttpSpacePrimitives in its default cookie-only auth mode.
      (globalThis as { silverbullet?: { bearerToken?: string } }).silverbullet
        ?.bearerToken,
    );

    this.eventedSpacePrimitives = new EventedSpacePrimitives(
      new CheckedSpacePrimitives(
        this.httpSpacePrimitives,
        this.bootConfig.readOnly,
      ),
      this.eventHook,
      this.ds,
    );

    // Kick off a regular file listing request to trigger events
    setInterval(() => {
      void this.eventedSpacePrimitives.fetchFileList();
    }, fetchFileListInterval + jitter());

    this.eventHook.addLocalListener("file:changed", async (name: string) => {
      console.log("Queueing index for", name);
      await this.objectIndex.clearFileIndex(name);
      await this.mq.send("indexQueue", name);
    });

    const space = new Space(
      this.eventedSpacePrimitives,
      this.eventHook,
      (name, page) =>
        this.clientSystem.localSyscall("index.resolveAnchor", [name, page]),
    );

    this.space = space;

    this.eventHook.addLocalListener(
      "file:changed",
      (path: string, oldHash: number, _newHash: number, ownWrite: boolean) => {
        if (
          !this.space.watchInterval ||
          this.currentPath() !== path ||
          oldHash === undefined ||
          // our own save landing, not somebody else's edit
          ownWrite
        ) {
          return;
        }
        if (isMarkdownPath(path)) {
          this.contentManager.reloadPageContent().catch(console.error);
        } else {
          // Documents (non-markdown) keep the reload path
          this.ui.flashNotification("Document changed elsewhere, reloading");
          void this.reloadEditor();
        }
      },
    );

    // Caching a list of known files for the wiki_link highlighter (that checks if a file exists)
    // And keeping it up to date as we go
    this.eventHook.addLocalListener("file:changed", (fileName: string) => {
      // Make sure this file is in the list of known pages
      this.clientSystem.allKnownFiles.add(fileName);
    });
    this.eventHook.addLocalListener("file:deleted", (fileName: string) => {
      this.clientSystem.allKnownFiles.delete(fileName);
    });
    this.eventHook.addLocalListener("file:listed", (allFiles: FileMeta[]) => {
      // Update list of known pages
      this.clientSystem.allKnownFiles.clear();
      allFiles.forEach((f) => {
        this.clientSystem.allKnownFiles.add(f.name);
      });
      this.clientSystem.knownFilesLoaded = true;
    });

    this.space.watch();

    this.realtimeEvents = new RealtimeEvents({
      probeFile: (name) => this.eventedSpacePrimitives.getFileMeta(name),
      syncFile: (name) =>
        this.clientSystem
          .localSyscall("sync.performFileSync", [name])
          .catch((e) => console.warn("[realtime] sync nudge failed", e)),
      syncSpace: () =>
        this.clientSystem
          .localSyscall("sync.performSpaceSync", [])
          .catch((e) => console.warn("[realtime] sync nudge failed", e)),
      refreshFileList: () =>
        this.eventedSpacePrimitives.fetchFileListWhenIdle(),
      serviceWorkerActive: () =>
        !!globalThis.navigator?.serviceWorker?.controller,
    });
    this.realtimeEvents.start(
      `${document.baseURI.replace(/\/*$/, "")}/.events`,
    );
  }

  currentPath(): Path {
    return this.ui.viewState.current?.path || this.onLoadRef.path;
  }

  currentName(): string {
    return getNameFromPath(
      this.ui.viewState.current?.path || this.onLoadRef.path,
    );
  }

  currentPageMeta(): PageMeta | undefined {
    return this.ui.viewState.current?.meta;
  }

  dispatchAppEvent(name: AppEvent, ...args: any[]): Promise<any[]> {
    return this.eventHook.dispatchEvent(name, ...args);
  }

  dispatchClickEvent(clickEvent: ClickEvent) {
    const editorState = this.editorView.state;
    const sTree = syntaxTree(editorState);
    const currentNode = sTree.resolveInner(clickEvent.pos);

    const parentNodes: string[] = this.extractParentNodes(
      editorState,
      currentNode,
    );
    const enrichedEvent: EnrichedClickEvent = {
      ...clickEvent,
      parentNodes,
    };
    return this.dispatchAppEvent("page:click", enrichedEvent);
  }

  save(immediate = false): Promise<void> {
    return this.contentManager.save(immediate);
  }

  reportError(e: any, context: string = "") {
    console.error(`Error during ${context}:`, e);

    // Don't show flash notifications for expected operational errors
    if (
      e.message === "Offline" ||
      e.name === "AbortError" ||
      e.name === "TimeoutError"
    ) {
      return;
    }

    if (e instanceof LuaRuntimeError) {
      this.ui.flashNotification(`Lua error: ${e.message}`, "error");
      const origin = resolveASTReference(e.sf.astCtx!);
      if (origin) {
        void client.navigate(origin);
      }
    } else {
      this.ui.flashNotification(`Error: ${e.message}`, "error");
    }
  }

  startPageNavigate(mode: "page" | "meta" | "document" | "all") {
    // Then show the page navigator
    this.ui.viewDispatch({ type: "start-navigate", mode });
    // And update the page list cache asynchronously
    this.updatePageListCache().catch(console.error);
    this.updateDocumentListCache().catch(console.error);
  }

  queryLuaObjects<T>(
    tag: string,
    query: LuaCollectionQuery,
    scopedVariables?: Record<string, any>,
  ): Promise<T[]> {
    return this.objectIndex.queryLuaObjects(
      this.clientSystem.spaceLuaEnv.env,
      tag,
      query,
      scopedVariables,
    );
  }

  /**
   * In headless mode, expose Lua eval functions on globalThis for CDP access
   * and signal readiness once the full index is complete.
   */
  private initHeadlessRuntime() {
    if (!globalThis.sbRuntime.headless) {
      return;
    }
    console.log("[RuntimeAPI] Headless mode, exposing eval functions");
    const spaceLuaEnv = this.clientSystem.spaceLuaEnv;

    const evalLuaCode = async (code: string) => {
      const ast = parseLua(code);
      const scriptEnv = new LuaEnv(spaceLuaEnv.env);
      const tl = new LuaEnv();
      tl.setLocal("_GLOBAL", spaceLuaEnv.env);
      const sf = new LuaStackFrame(tl, ast.ctx);
      const result = await evalStatement(ast, scriptEnv, sf);
      const returnValue =
        result &&
        typeof result === "object" &&
        "ctrl" in result &&
        result.ctrl === "return" &&
        Array.isArray(result.values)
          ? result.values[0]
          : result;
      return (await Promise.resolve(luaValueToJS(returnValue, sf))) ?? null;
    };

    globalThis.sbRuntime.evalLua = (expr: string) =>
      evalLuaCode(`return ${expr}`);
    globalThis.sbRuntime.evalLuaScript = evalLuaCode;

    // Signal readiness after widgets are fully ready (index complete +
    // editor state rebuild settled). Waiting on the widget-ready
    // transition ensures tests don't type into the editor mid-rebuild.
    void this.widgetsReady.then(() => {
      console.log(
        "[RuntimeAPI] Ready (eval functions exposed + widgets ready)",
      );
      globalThis.sbRuntime.ready = true;
    });
  }

  async updatePageListCache() {
    console.log("Updating page list cache");
    // Use the looser `isIndexAvailable` check: stale-but-present index
    // entries are still queryable, so we can take the index branch.
    const indexAvailable = await this.objectIndex.isIndexAvailable();

    let allPages: PageMeta[] = [];

    if (indexAvailable) {
      console.log("Initial index complete, loading full page list via index.");
      // Fetch indexed pages
      allPages = await this.queryLuaObjects<PageMeta>("page", {});
      // Overlay augmented meta values
      await this.pageMetaAugmenter.augmentObjectArray(allPages, "ref");
      // Fetch aspiring pages
      const aspiringPageNames = await this.queryLuaObjects<string>(
        "aspiring-page",
        { select: parseExpressionString("name"), distinct: true },
      );
      // Fetch any augmented page meta data (for now only lastOpened)
      // this.clientSystem.ds.query({prefix: })
      // Map and push aspiring pages directly into allPages
      allPages.push(
        ...aspiringPageNames.map(
          (name): PageMeta => ({
            ref: name,
            tag: "page",
            _isAspiring: true,
            name: name,
            created: "", // Aspiring pages don't have timestamps yet
            lastModified: "", // Aspiring pages don't have timestamps yet
            perm: "rw",
          }),
        ),
      );
    } else {
      console.log(
        "Initial sync not complete or index plug not loaded. Fetching page list directly using space.fetchPageList().",
      );
      try {
        // Call fetchPageList directly
        allPages = await this.space.fetchPageList();

        // Let's do some heuristic-based post processing
        for (const page of allPages) {
          // These are _mostly_ meta pages, let's add a tag for them
          if (page.name.startsWith("Library/")) {
            page.tags = ["meta"];
          }
        }
      } catch (e) {
        console.error("Failed to list pages directly from space:", e);
        // Handle error, maybe show notification or leave list empty
        this.ui.flashNotification(
          "Could not fetch page list directly.",
          "error",
        );
      }
    }

    this.ui.viewDispatch({
      type: "update-page-list",
      allPages: allPages,
    });

    // Only flip the readiness flag if allPages reflects the indexed,
    // transform-applied values (the index branch). The fallback branch
    // produces raw page meta without pageDecoration, so we keep
    // showing loading widgets until the index is back.
    if (indexAvailable) {
      this.pageListLoaded = true;
      this.maybeDispatchWidgetsReady();
    }

    // Async kick-off file listing to bring listing up to date
    void this.space.spacePrimitives.fetchFileList();
  }

  /**
   * If we just transitioned from "loading" to "ready" for widget
   * rendering, dispatch editor:reloadState so the editor rebuilds and
   * the loading placeholders get replaced with real widgets. Fires at
   * most once per session.
   */
  public maybeDispatchWidgetsReady() {
    if (this.widgetReadyDispatched) return;
    if (
      this.systemReady &&
      this.clientSystem.scriptsLoaded &&
      this.fullIndexCompleted &&
      this.pageListLoaded
    ) {
      this.widgetReadyDispatched = true;
      this.rebuildEditorState();
      this.resolveWidgetsReady();
    }
  }

  async updateDocumentListCache() {
    console.log("Updating document list cache");
    const allDocuments = await this.queryLuaObjects<DocumentMeta>(
      "document",
      {},
    );

    this.ui.viewDispatch({
      type: "update-document-list",
      allDocuments: allDocuments,
    });
  }

  async startCommandPalette() {
    const commands = this.ui.viewState.commands;
    await this.commandAugmenter.augmentObjectMap(commands);
    this.ui.viewDispatch({
      type: "show-palette",
      commands,
      context: client.getContext(),
    });
  }

  /**
   * Saves when a command was last run to the datastore for command palette ordering
   */
  async registerCommandRun(name: string) {
    await this.commandAugmenter.setAugmentation(name, {
      lastRun: Date.now(),
    });
  }

  async loadPlugs() {
    await this.clientSystem.reloadPlugsFromSpace(this.space);
    await this.dispatchAppEvent("plugs:loaded");
  }

  reconfigureLanguage() {
    if (this.markdownLanguageCompartment) {
      this.editorView.dispatch({
        effects: this.markdownLanguageCompartment.reconfigure(
          buildMarkdownLanguageExtension(this),
        ),
      });
    }
  }

  rebuildEditorState() {
    const editorView = this.editorView;
    // Preserve selection + scroll across the rebuild — this fires on
    // widget loading→ready transitions after the editor is already
    // interactive, so a reset to pos 0 / scrollTop 0 is jarring.
    const previousSelection = editorView.state.selection;
    const previousScrollTop = editorView.scrollDOM.scrollTop;

    let cursorWasVisible = false;
    try {
      const block = editorView.lineBlockAt(previousSelection.main.head);
      const scrollBottom =
        previousScrollTop + editorView.scrollDOM.clientHeight;
      cursorWasVisible =
        block.bottom > previousScrollTop && block.top < scrollBottom;
    } catch {
      // fall back to no-scroll
    }

    editorView.setState(
      createEditorState(
        this,
        this.currentName(),
        editorView.state.sliceDoc(),
        this.currentPageMeta()?.perm === "ro",
        previousSelection,
      ),
    );
    editorView.scrollDOM.scrollTop = previousScrollTop;

    if (cursorWasVisible) {
      editorView.dispatch({
        effects: EditorView.scrollIntoView(previousSelection.main.head),
      });
    }
  }

  // Code completion support
  async completeWithEvent(
    context: CompletionContext,
    eventName: AppEvent,
  ): Promise<CompletionResult | SlashCompletions | null> {
    const editorState = context.state;
    const selection = editorState.selection.main;
    const line = editorState.doc.lineAt(selection.from);
    const linePrefix = line.text.slice(0, selection.from - line.from);

    // Build up list of parent nodes, some completions need this
    const sTree = syntaxTree(editorState);
    const currentNode = sTree.resolveInner(editorState.selection.main.from);

    const parentNodes: string[] = this.extractParentNodes(
      editorState,
      currentNode,
    );

    // Dispatch the event
    const results = await this.dispatchAppEvent(eventName, {
      pageName: this.currentName(),
      linePrefix,
      pos: selection.from,
      parentNodes,
    } as CompleteEvent);

    // Merge results
    let currentResult: CompletionResult | null = null;
    for (const result of results) {
      if (!result) {
        continue;
      }
      if (currentResult) {
        // Let's see if we can merge results
        if (currentResult.from !== result.from) {
          console.error(
            "Got completion results from multiple sources with different `from` locators, cannot deal with that",
          );
          console.error(
            "Previously had",
            currentResult,
            "now also got",
            result,
          );
          return null;
        } else {
          // Merge
          currentResult = {
            from: result.from,
            options: [...currentResult.options, ...result.options],
          };
        }
      } else {
        currentResult = result;
      }
    }
    if (!currentResult) {
      return null;
    }
    return {
      ...currentResult,
      options: currentResult.options.map(withCompletionInfo),
    };
  }

  isReadOnlyMode(): boolean {
    return this.bootConfig.readOnly || this.currentPageMeta()?.perm === "ro";
  }

  public extractParentNodes(editorState: EditorState, currentNode: SyntaxNode) {
    const parentNodes: string[] = [];
    if (currentNode) {
      let node: SyntaxNode | null = currentNode;
      do {
        if (["FencedCode", "FrontMatter"].includes(node.name)) {
          const body = editorState.sliceDoc(node.from + 3, node.to - 3);
          parentNodes.push(`${node.name}:${body}`);
        } else if (node.name === "LuaDirective") {
          const body = editorState.sliceDoc(node.from + 2, node.to - 1);
          parentNodes.push(`${node.name}:${body}`);
        } else {
          parentNodes.push(node.name);
        }
        node = node.parent;
      } while (node);
    }
    return parentNodes;
  }

  editorComplete(context: CompletionContext): Promise<CompletionResult | null> {
    return this.completeWithEvent(
      context,
      "editor:complete",
    ) as Promise<CompletionResult | null>;
  }

  reloadEditor() {
    return this.contentManager.reloadEditor();
  }

  // Focus the editor
  focus() {
    const viewState = this.ui.viewState;
    if (
      [
        viewState.showCommandPalette,
        viewState.showPageNavigator,
        viewState.showFilterBox,
        viewState.showConfirm,
        viewState.showPrompt,
      ].some(Boolean)
    ) {
      // console.log("not focusing");
      // Some other modal UI element is visible, don't focus editor now
      return;
    }

    if (this.contentManager.isDocumentEditor()) {
      this.contentManager.documentEditor.focus();
    } else {
      this.editorView.focus();
    }
  }

  getIndexRef(): Ref {
    return parseToRef(this.bootConfig.indexPage) || { path: "index.md" };
  }

  /**
   * Navigates the client to a particular ref (ingoring previous state)
   */
  navigate(ref: Ref | null, replaceState = false, newWindow = false) {
    return this._navigate(ref, replaceState, newWindow, false);
  }

  /**
   * Opens a particular ref in the client restoring previous state if available
   */
  open(ref: Ref | null, replaceState = false, newWindow = false) {
    return this._navigate(ref, replaceState, newWindow, true);
  }

  private async _navigate(
    ref: Ref | null,
    replaceState = false,
    newWindow = false,
    restore = false,
  ) {
    ref ??= this.getIndexRef();

    // Resolve $-anchor refs into a concrete page + position. The page
    // navigator only knows about position/header/linecolumn details, so
    // we have to translate here.
    if (ref.details?.type === "anchor") {
      const anchorName = ref.details.name;
      const pageFilter = ref.path
        ? ref.path.endsWith(".md")
          ? ref.path.slice(0, -3)
          : ref.path
        : undefined;
      const result: ResolveAnchorResult = await this.clientSystem.localSyscall(
        "index.resolveAnchor",
        [anchorName, pageFilter],
      );
      if (!result.ok) {
        if (result.reason === "missing") {
          this.ui.flashNotification(
            `Anchor not found: $${anchorName}`,
            "error",
          );
        } else {
          const pages = result.hits.map((h) => h.page).join(", ");
          this.ui.flashNotification(
            `Duplicate anchor $${anchorName} on pages: ${pages}`,
            "error",
          );
        }
        return;
      }
      ref = {
        ...ref,
        path: `${result.page}.md`,
        details: { type: "position", pos: result.range[0] },
      };
    }

    if (newWindow) {
      console.log(
        "Navigating to new page in new window",
        `${document.baseURI}${encodePageURI(encodeRef(ref))}`,
      );
      const win = globalThis.open(
        `${document.baseURI}${encodePageURI(encodeRef(ref))}`,
        "_blank",
      );
      if (win) {
        win.focus();
      }
      return;
    }

    await this.pageNavigator!.navigate(ref, replaceState, restore);
    this.focus();
  }

  openUrl(url: string, existingWindow = false) {
    if (!existingWindow) {
      const win = globalThis.open(url, "_blank");
      if (win) {
        win.focus();
      }
    } else {
      location.href = url;
    }
  }

  async loadCustomStyles() {
    if (this.bootConfig.disableSpaceStyle) {
      console.warn("Not loading custom styles, since space style is disabled");
      return;
    }
    if (!(await this.objectIndex.isIndexAvailable())) {
      console.warn(
        "Not loading custom styles, since no index is available yet",
      );
      return;
    }

    const spaceStyles = await this.queryLuaObjects<StyleObject>("space-style", {
      objectVariable: "_",
      orderBy: [
        {
          expr: parseExpressionString("_.priority"),
          desc: true,
        },
      ],
    });
    if (!spaceStyles) {
      return;
    }

    // Prepare separate <style> tag per custom style (for robustness)
    const customStylesContent = spaceStyles
      .map((s) => `<style>${s.style}</style>`)
      .join("\n\n");
    this.ui.viewDispatch({
      type: "set-ui-option",
      key: "customStyles",
      value: customStylesContent,
    });
    document.getElementById("custom-styles")!.innerHTML = customStylesContent;
  }

  async runCommandByName(name: string, args?: any[]) {
    const cmd = this.ui.viewState.commands.get(name);
    if (cmd) {
      if (args) {
        await cmd.run!(args);
      } else {
        await cmd.run!();
      }
    } else {
      throw new Error(`Command ${name} not found`);
    }
  }

  getCommandsByContext(state: AppViewState): Map<string, Command> {
    const currentEditor = client.contentManager.documentEditor?.name;
    const readOnly = this.isReadOnlyMode();
    const commands = new Map(state.commands);
    for (const [k, v] of state.commands.entries()) {
      if (
        v.contexts &&
        (!state.showCommandPaletteContext ||
          !v.contexts.includes(state.showCommandPaletteContext))
      ) {
        commands.delete(k);
      }

      const requiredEditor = v.requireEditor;
      if (!isValidEditor(currentEditor, requiredEditor)) {
        commands.delete(k);
      }

      // Hide write-mode commands when the current page (or space) is read-only.
      // CommandHook only filters on the space-wide read-only flag, so per-page
      // read-only pages would otherwise still expose "rw" commands here.
      if (readOnly && v.requireMode === "rw") {
        commands.delete(k);
      }
    }

    return commands;
  }

  getContext(): string | undefined {
    const state = this.editorView.state;
    const selection = state.selection.main;
    if (selection.empty) {
      return syntaxTree(state).resolveInner(selection.from).type.name;
    }
    return;
  }

  async handleServiceWorkerMessage(message: ServiceWorkerSourceMessage) {
    switch (message.type) {
      case "space-sync-complete": {
        const isFirstSync = !this.fullSyncCompleted;
        this.fullSyncCompleted = true;
        // Only trigger a version-bump reindex once we've also confirmed the
        // server is on the same publicVersion as this client — otherwise the
        // reindex could run against stale plug code that's about to be
        // replaced by the in-progress upgrade.
        if (this.versionsInSync) {
          void this.objectIndex.ensureFullIndex(this.space);
        }

        if (isFirstSync && message.operations > 0) {
          // First sync pulled new content — reload the current page
          // (it may have been empty because the file didn't exist locally yet)
          void this.reloadEditor();
          // Re-evaluate CONFIG and space scripts now that sync has pulled them
          void this.clientSystem.reloadState();
        }
        break;
      }
      case "online-status": {
        this.ui.viewDispatch({
          type: "online-status-change",
          isOnline: message.isOnline,
        });
        break;
      }
      case "auth-error": {
        alert(message.message);
        if (
          message.actionOrRedirectHeader &&
          message.actionOrRedirectHeader !== "reload"
        ) {
          location.href = message.actionOrRedirectHeader;
        } else {
          location.reload();
        }
        break;
      }
      case "server-version": {
        if (message.serverVersion === publicVersion) {
          const wasInSync = this.versionsInSync;
          this.versionsInSync = true;
          // If sync already completed before we learned versions were aligned,
          // kick off the deferred reindex check now.
          if (!wasInSync && this.fullSyncCompleted) {
            void this.objectIndex.ensureFullIndex(this.space);
          }
        } else if (!this.versionMismatchNotified) {
          this.versionMismatchNotified = true;
          this.ui.flashNotification(
            "Plainleaf 已更新，请刷新页面以使用新版本。",
            "warning",
            {
              timeout: 0,
              actions: [
                {
                  name: "立即更新",
                  run: () => void reloadWithUpdatedServiceWorker(),
                },
              ],
            },
          );
        }
        break;
      }
    }

    // Also dispatch it on the event hook for any other listeners
    await this.eventHook.dispatchEvent(
      `service-worker:${message.type}`,
      message,
    );
  }

  private async initNavigator() {
    this.pageNavigator = new PathPageNavigator(this);

    this.pageNavigator.subscribe(async (locationState) => {
      console.log(`Now navigating to ${encodeRef(locationState)}`);

      if (isMarkdownPath(locationState.path)) {
        await this.contentManager.loadPage(locationState);
      } else {
        await this.contentManager.loadDocumentEditor(locationState);
      }

      // Persist this page as the last opened page, we'll use this for cold start PWA loads
      await this.ds.set(["client", "lastOpenedPath"], locationState.path);
    });

    // Initial navigation
    let ref = this.onLoadRef;

    if (ref.details?.type === "header" && ref.details.header === "boot") {
      const path = (await this.ds.get(["client", "lastOpenedPath"])) as Path;

      if (path) {
        console.log("Navigating to last opened page", getNameFromPath(path));
        ref = { path };
      } else {
        // Strip the #boot detail — it's not a real header
        delete ref.details;
      }
    }

    await this.navigate(ref, true);

    console.log("Focusing editor");
    this.focus();
  }

  async wipeClient() {
    // Clean out _other_ IndexedDB databases
    console.log("Wiping IndexedDB databses not connected to this space...");
    const dbName = (this.ds.kv as any).dbName;
    const suffix = dbName.replace("sb_data", "");
    if (indexedDB.databases) {
      const allDbs = await indexedDB.databases();
      for (const db of allDbs) {
        if (!db.name?.endsWith(suffix)) {
          console.log("Deleting database", db.name);
          indexedDB.deleteDatabase(db.name!);
        }
      }
    }
    // Instructe service worker to wipe
    if (navigator.serviceWorker?.controller) {
      // We will attempt to unregister the service worker, best effort
      await new Promise<void>((resolve) => {
        navigator.serviceWorker.addEventListener("message", async (e: any) => {
          const message: ServiceWorkerSourceMessage = e.data;
          if (message.type === "dataWiped") {
            console.log(
              "Got data wipe confirm, uninstalling service worker now",
            );
            const registrations =
              await navigator.serviceWorker.getRegistrations();
            for (const registration of registrations) {
              await registration.unregister();
            }
            console.log("Unregistered all service workers");
            resolve();
          }
        });
        // Send wipe request
        navigator.serviceWorker.getRegistration().then((registration) => {
          console.log(
            "Sending data wipe request to service worker",
            registration,
          );
          registration?.active?.postMessage({
            type: "wipe-data",
          } as ServiceWorkerTargetMessage);
        });
      });
    } else {
      console.info(
        "Service workers not enabled (no HTTPS?), so not unregistering.",
      );
    }
    console.log("Stopping all systems");
    this.space.unwatch();
    this.realtimeEvents?.stop();

    console.log("Clearing data store");
    await this.ds.kv.clear();
    console.log("Clearing complete.");
  }

  public async postServiceWorkerMessage(message: ServiceWorkerTargetMessage) {
    const registration = await navigator.serviceWorker.getRegistration();
    if (!registration?.active) {
      console.warn("No active service worker, skipping message:", message.type);
      return;
    }
    registration.active.postMessage(message);
  }
}