// Third party web dependencies
import {
  CompletionContext,
  CompletionResult,
  EditorView,
  gitIgnoreCompiler,
  syntaxTree,
} from "../common/deps.ts";
import { Space } from "./space.ts";
import { FilterOption, PageMeta } from "./types.ts";
import { parseYamlSettings } from "../common/util.ts";
import { EventHook } from "../plugos/hooks/event.ts";
import { AppCommand } from "./hooks/command.ts";
import { PathPageNavigator } from "./navigator.ts";

import { AppViewState, BuiltinSettings } from "./types.ts";

import type { AppEvent, CompleteEvent } from "../plug-api/app_event.ts";
import { throttle } from "../common/async_util.ts";
import { PlugSpacePrimitives } from "../common/spaces/plug_space_primitives.ts";
import { IndexedDBSpacePrimitives } from "../common/spaces/indexeddb_space_primitives.ts";
import { FileMetaSpacePrimitives } from "../common/spaces/file_meta_space_primitives.ts";
import { EventedSpacePrimitives } from "../common/spaces/evented_space_primitives.ts";
import { SyncService } from "./sync_service.ts";
import { simpleHash } from "../common/crypto.ts";
import { DexieKVStore } from "../plugos/lib/kv_store.dexie.ts";
import { SyncStatus } from "../common/spaces/sync.ts";
import { HttpSpacePrimitives } from "../common/spaces/http_space_primitives.ts";
import { FallbackSpacePrimitives } from "../common/spaces/fallback_space_primitives.ts";
import { FilteredSpacePrimitives } from "../common/spaces/filtered_space_primitives.ts";
import { isValidPageName } from "$sb/lib/page.ts";
import { ClientSystem } from "./client_system.ts";
import { createEditorState } from "./editor_state.ts";
import { OpenPages } from "./open_pages.ts";
import { MainUI } from "./editor_ui.tsx";
const frontMatterRegex = /^---\n(([^\n]|\n)*?)---\n/;

const autoSaveInterval = 1000;

declare global {
  interface Window {
    // Injected via index.html
    silverBulletConfig: {
      spaceFolderPath: string;
    };
    client: Client;
  }
}

// TODO: Oh my god, need to refactor this
export class Client {
  editorView?: EditorView;
  pageNavigator?: PathPageNavigator;

  space: Space;

  remoteSpacePrimitives: HttpSpacePrimitives;
  plugSpaceRemotePrimitives: PlugSpacePrimitives;

  saveTimeout?: number;

  debouncedUpdateEvent = throttle(() => {
    this.eventHook
      .dispatchEvent("editor:updated")
      .catch((e) => console.error("Error dispatching editor:updated event", e));
  }, 1000);
  system: ClientSystem;

  // Track if plugs have been updated since sync cycle
  fullSyncCompleted = false;

  // Runtime state (that doesn't make sense in viewState)
  syncService: SyncService;
  settings?: BuiltinSettings;
  kvStore: DexieKVStore;

  // Event bus used to communicate between components
  eventHook: EventHook;

  ui: MainUI;
  openPages: OpenPages;

  constructor(
    parent: Element,
  ) {
    const runtimeConfig = window.silverBulletConfig;

    // Generate a semi-unique prefix for the database so not to reuse databases for different space paths
    const dbPrefix = "" + simpleHash(window.silverBulletConfig.spaceFolderPath);

    this.kvStore = new DexieKVStore(
      `${dbPrefix}_store`,
      "data",
      globalThis.indexedDB,
    );

    // Event hook
    this.eventHook = new EventHook();

    // Instantiate a PlugOS system
    this.system = new ClientSystem(
      this,
      this.kvStore,
      dbPrefix,
      this.eventHook,
    );

    // Setup space
    this.remoteSpacePrimitives = new HttpSpacePrimitives(
      location.origin,
      runtimeConfig.spaceFolderPath,
      true,
    );

    this.plugSpaceRemotePrimitives = new PlugSpacePrimitives(
      this.remoteSpacePrimitives,
      this.system.namespaceHook,
    );

    let fileFilterFn: (s: string) => boolean = () => true;

    const localSpacePrimitives = new FilteredSpacePrimitives(
      new FileMetaSpacePrimitives(
        new EventedSpacePrimitives(
          // Using fallback space primitives here to allow (by default) local reads to "fall through" to HTTP when files aren't synced yet
          new FallbackSpacePrimitives(
            new IndexedDBSpacePrimitives(
              `${dbPrefix}_space`,
              globalThis.indexedDB,
            ),
            this.plugSpaceRemotePrimitives,
          ),
          this.eventHook,
        ),
        this.system.indexSyscalls,
      ),
      (meta) => fileFilterFn(meta.name),
      async () => {
        await this.loadSettings();
        if (typeof this.settings?.spaceIgnore === "string") {
          fileFilterFn = gitIgnoreCompiler(this.settings.spaceIgnore).accepts;
        } else {
          fileFilterFn = () => true;
        }
      },
    );

    this.space = new Space(localSpacePrimitives, this.kvStore);
    this.space.watch();

    this.syncService = new SyncService(
      localSpacePrimitives,
      this.plugSpaceRemotePrimitives,
      this.kvStore,
      this.eventHook,
      (path) => {
        // TODO: At some point we should remove the data.db exception here
        return path !== "data.db" &&
            // Exclude all plug space primitives paths
            !this.plugSpaceRemotePrimitives.isLikelyHandled(path) ||
          // Except federated ones
          path.startsWith("!");
      },
    );

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

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

    this.openPages = new OpenPages(this.editorView);
  }

  get currentPage(): string | undefined {
    return this.ui.viewState.currentPage;
  }

  async init() {
    this.focus();

    this.space.on({
      pageChanged: (meta) => {
        // Only reload when watching the current page (to avoid reloading when switching pages)
        if (this.space.watchInterval && this.currentPage === meta.name) {
          console.log("Page changed elsewhere, reloading");
          this.flashNotification("Page changed elsewhere, reloading");
          this.reloadPage();
        }
      },
      pageListUpdated: (pages) => {
        this.ui.viewDispatch({
          type: "pages-listed",
          pages: pages,
        });
      },
    });

    // Load settings
    this.settings = await this.loadSettings();

    this.pageNavigator = new PathPageNavigator(
      this.settings.indexPage,
    );

    await this.reloadPlugs();

    this.pageNavigator.subscribe(async (pageName, pos: number | string) => {
      console.log("Now navigating to", pageName);
      if (!this.editorView) {
        return;
      }

      const stateRestored = await this.loadPage(pageName);
      if (pos) {
        if (typeof pos === "string") {
          console.log("Navigating to anchor", pos);

          // We're going to look up the anchor through a direct page store query...
          // TODO: This should be extracted
          const posLookup = await this.system.localSyscall(
            "index.get",
            [
              pageName,
              `a:${pageName}:${pos}`,
            ],
          );

          if (!posLookup) {
            return this.flashNotification(
              `Could not find anchor @${pos}`,
              "error",
            );
          } else {
            pos = +posLookup;
          }
        }
        this.editorView.dispatch({
          selection: { anchor: pos },
          effects: EditorView.scrollIntoView(pos, { y: "start" }),
        });
      } else if (!stateRestored) {
        // Somewhat ad-hoc way to determine if the document contains frontmatter and if so, putting the cursor _after it_.
        const pageText = this.editorView.state.sliceDoc();

        // Default the cursor to be at position 0
        let initialCursorPos = 0;
        const match = frontMatterRegex.exec(pageText);
        if (match) {
          // Frontmatter found, put cursor after it
          initialCursorPos = match[0].length;
        }
        // By default scroll to the top
        this.editorView.scrollDOM.scrollTop = 0;
        this.editorView.dispatch({
          selection: { anchor: initialCursorPos },
          // And then scroll down if required
          scrollIntoView: true,
        });
      }
    });

    this.loadCustomStyles().catch(console.error);

    // Kick off background sync
    this.syncService.start();

    this.eventHook.addLocalListener("sync:success", async (operations) => {
      // console.log("Operations", operations);
      if (operations > 0) {
        // Update the page list
        await this.space.updatePageList();
      }
      if (operations !== undefined) {
        // "sync:success" is called with a number of operations only from syncSpace(), not from syncing individual pages
        this.fullSyncCompleted = true;
      }
      if (this.system.plugsUpdated) {
        // To register new commands, update editor state based on new plugs
        this.rebuildEditorState();
        this.dispatchAppEvent("editor:pageLoaded", this.currentPage);
        if (operations) {
          // Likely initial sync so let's show visually that we're synced now
          // this.flashNotification(`Synced ${operations} files`, "info");
          this.showProgress(100);
        }
      }
      // Reset for next sync cycle
      this.system.plugsUpdated = false;

      this.ui.viewDispatch({ type: "sync-change", synced: true });
    });
    this.eventHook.addLocalListener("sync:error", (_name) => {
      this.ui.viewDispatch({ type: "sync-change", synced: false });
    });
    this.eventHook.addLocalListener("sync:conflict", (name) => {
      this.flashNotification(
        `Sync: conflict detected for ${name} - conflict copy created`,
        "error",
      );
    });
    this.eventHook.addLocalListener("sync:progress", (status: SyncStatus) => {
      this.showProgress(
        Math.round(status.filesProcessed / status.totalFiles * 100),
      );
    });

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

  async loadSettings(): Promise<BuiltinSettings> {
    let settingsText: string | undefined;

    try {
      settingsText = (await this.space.readPage("SETTINGS")).text;
    } catch {
      console.log("No SETTINGS page, falling back to default");
      settingsText = "```yaml\nindexPage: index\n```\n";
    }
    const settings = parseYamlSettings(settingsText!) as BuiltinSettings;

    if (!settings.indexPage) {
      settings.indexPage = "index";
    }
    return settings;
  }

  save(immediate = false): Promise<void> {
    return new Promise((resolve, reject) => {
      if (this.saveTimeout) {
        clearTimeout(this.saveTimeout);
      }
      this.saveTimeout = setTimeout(
        () => {
          if (this.currentPage) {
            if (
              !this.ui.viewState.unsavedChanges ||
              this.ui.viewState.uiOptions.forcedROMode
            ) {
              // No unsaved changes, or read-only mode, not gonna save
              return resolve();
            }
            console.log("Saving page", this.currentPage);
            this.space
              .writePage(
                this.currentPage,
                this.editorView!.state.sliceDoc(0),
                true,
              )
              .then(async (meta) => {
                this.ui.viewDispatch({ type: "page-saved" });
                await this.dispatchAppEvent(
                  "editor:pageSaved",
                  this.currentPage,
                  meta,
                );
                resolve();
              })
              .catch((e) => {
                this.flashNotification(
                  "Could not save page, retrying again in 10 seconds",
                  "error",
                );
                this.saveTimeout = setTimeout(this.save.bind(this), 10000);
                reject(e);
              });
          } else {
            resolve();
          }
        },
        immediate ? 0 : autoSaveInterval,
      );
    });
  }

  flashNotification(message: string, type: "info" | "error" = "info") {
    const id = Math.floor(Math.random() * 1000000);
    this.ui.viewDispatch({
      type: "show-notification",
      notification: {
        id,
        type,
        message,
        date: new Date(),
      },
    });
    setTimeout(
      () => {
        this.ui.viewDispatch({
          type: "dismiss-notification",
          id: id,
        });
      },
      type === "info" ? 4000 : 5000,
    );
  }

  progressTimeout?: number;

  showProgress(progressPerc: number) {
    this.ui.viewDispatch({
      type: "set-progress",
      progressPerc,
    });
    if (this.progressTimeout) {
      clearTimeout(this.progressTimeout);
    }
    this.progressTimeout = setTimeout(
      () => {
        this.ui.viewDispatch({
          type: "set-progress",
        });
      },
      10000,
    );
  }

  filterBox(
    label: string,
    options: FilterOption[],
    helpText = "",
    placeHolder = "",
  ): Promise<FilterOption | undefined> {
    return new Promise((resolve) => {
      this.ui.viewDispatch({
        type: "show-filterbox",
        label,
        options,
        placeHolder,
        helpText,
        onSelect: (option: any) => {
          this.ui.viewDispatch({ type: "hide-filterbox" });
          this.focus();
          resolve(option);
        },
      });
    });
  }

  prompt(
    message: string,
    defaultValue = "",
  ): Promise<string | undefined> {
    return new Promise((resolve) => {
      this.ui.viewDispatch({
        type: "show-prompt",
        message,
        defaultValue,
        callback: (value: string | undefined) => {
          this.ui.viewDispatch({ type: "hide-prompt" });
          this.focus();
          resolve(value);
        },
      });
    });
  }

  confirm(
    message: string,
  ): Promise<boolean> {
    return new Promise((resolve) => {
      this.ui.viewDispatch({
        type: "show-confirm",
        message,
        callback: (value: boolean) => {
          this.ui.viewDispatch({ type: "hide-confirm" });
          this.focus();
          resolve(value);
        },
      });
    });
  }

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

  async reloadPlugs() {
    console.log("Loading plugs");
    await this.system.reloadPlugsFromSpace(this.space);
    this.rebuildEditorState();
    await this.dispatchAppEvent("plugs:loaded");
  }

  rebuildEditorState() {
    const editorView = this.editorView;
    console.log("Rebuilding editor state");

    this.system.updateMarkdownParser();

    if (editorView && this.currentPage) {
      // And update the editor if a page is loaded
      this.openPages.saveState(this.currentPage);

      editorView.setState(
        createEditorState(
          this,
          this.currentPage,
          editorView.state.sliceDoc(),
          this.ui.viewState.currentPageMeta?.perm === "ro",
        ),
      );
      if (editorView.contentDOM) {
        this.tweakEditorDOM(
          editorView.contentDOM,
        );
      }

      this.openPages.restoreState(this.currentPage);
    }
  }

  // Code completion support
  private async completeWithEvent(
    context: CompletionContext,
    eventName: AppEvent,
  ): Promise<CompletionResult | 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);

    const results = await this.dispatchAppEvent(eventName, {
      pageName: this.currentPage!,
      linePrefix,
      pos: selection.from,
    } as CompleteEvent);
    let actualResult = null;
    for (const result of results) {
      if (result) {
        if (actualResult) {
          console.error(
            "Got completion results from multiple sources, cannot deal with that",
          );
          console.error("Previously had", actualResult, "now also got", result);
          return null;
        }
        actualResult = result;
      }
    }
    return actualResult;
  }

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

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

  async reloadPage() {
    console.log("Reloading page");
    clearTimeout(this.saveTimeout);
    await this.loadPage(this.currentPage!);
  }

  focus() {
    this.editorView!.focus();
  }

  async navigate(
    name: string,
    pos?: number | string,
    replaceState = false,
    newWindow = false,
  ) {
    if (!name) {
      name = this.settings!.indexPage;
    }

    if (!isValidPageName(name)) {
      return this.flashNotification(
        "Invalid page name: page names cannot end with a file extension nor start with a '.'",
        "error",
      );
    }

    if (newWindow) {
      const win = window.open(`${location.origin}/${name}`, "_blank");
      if (win) {
        win.focus();
      }
      return;
    }
    await this.pageNavigator!.navigate(name, pos, replaceState);
  }

  async loadPage(pageName: string): Promise<boolean> {
    const loadingDifferentPage = pageName !== this.currentPage;
    const editorView = this.editorView;
    if (!editorView) {
      return false;
    }

    const previousPage = this.currentPage;

    // Persist current page state and nicely close page
    if (previousPage) {
      this.openPages.saveState(previousPage);
      this.space.unwatchPage(previousPage);
      if (previousPage !== pageName) {
        await this.save(true);
      }
    }

    this.ui.viewDispatch({
      type: "page-loading",
      name: pageName,
    });

    // Fetch next page to open
    let doc;
    try {
      doc = await this.space.readPage(pageName);
      if (doc.meta.contentType.startsWith("text/html")) {
        throw new Error("Got HTML page, not markdown");
      }
    } catch (e: any) {
      // Not found, new page
      console.log("Creating new page", pageName);
      doc = {
        text: "",
        meta: { name: pageName, lastModified: 0, perm: "rw" } as PageMeta,
      };
    }

    const editorState = createEditorState(
      this,
      pageName,
      doc.text,
      doc.meta.perm === "ro",
    );
    editorView.setState(editorState);
    if (editorView.contentDOM) {
      this.tweakEditorDOM(editorView.contentDOM);
    }
    const stateRestored = this.openPages.restoreState(pageName);
    this.space.watchPage(pageName);

    this.ui.viewDispatch({
      type: "page-loaded",
      meta: doc.meta,
    });

    // Note: these events are dispatched asynchronously deliberately (not waiting for results)
    if (loadingDifferentPage) {
      this.eventHook.dispatchEvent("editor:pageLoaded", pageName, previousPage)
        .catch(
          console.error,
        );
    } else {
      this.eventHook.dispatchEvent("editor:pageReloaded", pageName).catch(
        console.error,
      );
    }

    return stateRestored;
  }

  tweakEditorDOM(contentDOM: HTMLElement) {
    contentDOM.spellcheck = true;
    contentDOM.setAttribute("autocorrect", "on");
    contentDOM.setAttribute("autocapitalize", "on");
  }

  async loadCustomStyles() {
    if (this.settings?.customStyles) {
      try {
        const { text: stylesText } = await this.space.readPage(
          this.settings?.customStyles,
        );
        const cssBlockRegex = /```css([^`]+)```/;
        const match = cssBlockRegex.exec(stylesText);
        if (!match) {
          return;
        }
        const css = match[1];
        document.getElementById("custom-styles")!.innerHTML = css;
      } catch (e: any) {
        console.error("Failed to load custom styles", e);
      }
    }
  }

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

  getCommandsByContext(
    state: AppViewState,
  ): Map<string, AppCommand> {
    const commands = new Map(state.commands);
    for (const [k, v] of state.commands.entries()) {
      if (
        v.command.contexts &&
        (!state.showCommandPaletteContext ||
          !v.command.contexts.includes(state.showCommandPaletteContext))
      ) {
        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;
  }
}