import {ipcRenderer, remote} from "electron";
import fs from "fs";
import path from "path";

import * as ConfigUtil from "../../../common/config-util";
import {HTML, html} from "../../../common/html";
import * as SystemUtil from "../utils/system-util";

import {generateNodeFromHTML} from "./base";
import {contextMenu} from "./context-menu";
import handleExternalLink from "./handle-external-link";

const {app, dialog} = remote;

const shouldSilentWebview = ConfigUtil.getConfigItem("silent");

interface WebViewProps {
  $root: Element;
  index: number;
  tabIndex: number;
  url: string;
  role: string;
  name: string;
  isActive: () => boolean;
  switchLoading: (loading: boolean, url: string) => void;
  onNetworkError: (index: number) => void;
  nodeIntegration: boolean;
  preload: boolean;
  onTitleChange: () => void;
  hasPermission?: (origin: string, permission: string) => boolean;
}

export default class WebView {
  props: WebViewProps;
  zoomFactor: number;
  badgeCount: number;
  loading: boolean;
  customCSS: string;
  $webviewsContainer: DOMTokenList;
  $el: Electron.WebviewTag;
  domReady?: Promise<void>;

  constructor(props: WebViewProps) {
    this.props = props;
    this.zoomFactor = 1;
    this.loading = true;
    this.badgeCount = 0;
    this.customCSS = ConfigUtil.getConfigItem("customCSS");
    this.$webviewsContainer = document.querySelector(
      "#webviews-container",
    ).classList;
  }

  templateHTML(): HTML {
    return html`
      <webview
        class="disabled"
        data-tab-id="${this.props.tabIndex}"
        src="${this.props.url}"
        ${new HTML({html: this.props.nodeIntegration ? "nodeIntegration" : ""})}
        ${new HTML({html: this.props.preload ? 'preload="js/preload.js"' : ""})}
        partition="persist:webviewsession"
        name="${this.props.name}"
        webpreferences="
          contextIsolation=${!this.props.nodeIntegration},
          spellcheck=${Boolean(ConfigUtil.getConfigItem("enableSpellchecker"))},
          worldSafeExecuteJavaScript=true
        "
      >
      </webview>
    `;
  }

  init(): void {
    this.$el = generateNodeFromHTML(this.templateHTML()) as Electron.WebviewTag;
    this.domReady = new Promise((resolve) => {
      this.$el.addEventListener(
        "dom-ready",
        () => {
          resolve();
        },
        true,
      );
    });
    this.props.$root.append(this.$el);

    this.registerListeners();
  }

  registerListeners(): void {
    this.$el.addEventListener("new-window", (event) => {
      handleExternalLink.call(this, event);
    });

    if (shouldSilentWebview) {
      this.$el.addEventListener("dom-ready", () => {
        this.$el.setAudioMuted(true);
      });
    }

    this.$el.addEventListener("page-title-updated", (event) => {
      const {title} = event;
      this.badgeCount = this.getBadgeCount(title);
      this.props.onTitleChange();
    });

    this.$el.addEventListener("did-navigate-in-page", (event) => {
      const isSettingPage = event.url.includes("renderer/preference.html");
      if (isSettingPage) {
        return;
      }

      this.canGoBackButton();
    });

    this.$el.addEventListener("did-navigate", () => {
      this.canGoBackButton();
    });

    this.$el.addEventListener("page-favicon-updated", (event) => {
      const {favicons} = event;

      // This returns a string of favicons URL. If there is a PM counts in unread messages then the URL would be like
      // https://chat.zulip.org/static/images/favicon/favicon-pms.png
      if (
        favicons[0].indexOf("favicon-pms") > 0 &&
        process.platform === "darwin"
      ) {
        // This api is only supported on macOS
        app.dock.setBadge("●");
        // Bounce the dock
        if (ConfigUtil.getConfigItem("dockBouncing")) {
          app.dock.bounce();
        }
      }
    });

    this.$el.addEventListener("dom-ready", () => {
      const webContents = remote.webContents.fromId(
        this.$el.getWebContentsId(),
      );
      webContents.addListener("context-menu", (event, menuParameters) => {
        contextMenu(webContents, event, menuParameters);
      });

      if (this.props.role === "server") {
        this.$el.classList.add("onload");
      }

      this.loading = false;
      this.props.switchLoading(false, this.props.url);
      this.show();

      // Refocus text boxes after reload
      // Remove when upstream issue https://github.com/electron/electron/issues/14474 is fixed
      this.$el.blur();
      this.$el.focus();
    });

    this.$el.addEventListener("did-fail-load", (event) => {
      const {errorDescription} = event;
      const hasConnectivityError = SystemUtil.connectivityERR.includes(
        errorDescription,
      );
      if (hasConnectivityError) {
        console.error("error", errorDescription);
        if (!this.props.url.includes("network.html")) {
          this.props.onNetworkError(this.props.index);
        }
      }
    });

    this.$el.addEventListener("did-start-loading", () => {
      const isSettingPage = this.props.url.includes("renderer/preference.html");
      if (!isSettingPage) {
        this.props.switchLoading(true, this.props.url);
      }
    });

    this.$el.addEventListener("did-stop-loading", () => {
      this.props.switchLoading(false, this.props.url);
    });
  }

  getBadgeCount(title: string): number {
    const messageCountInTitle = /\((\d+)\)/.exec(title);
    return messageCountInTitle ? Number(messageCountInTitle[1]) : 0;
  }

  showNotificationSettings(): void {
    ipcRenderer.sendTo(
      this.$el.getWebContentsId(),
      "show-notification-settings",
    );
  }

  show(): void {
    // Do not show WebView if another tab was selected and this tab should be in background.
    if (!this.props.isActive()) {
      return;
    }

    // To show or hide the loading indicator in the the active tab
    if (this.loading) {
      this.$webviewsContainer.remove("loaded");
    } else {
      this.$webviewsContainer.add("loaded");
    }

    this.$el.classList.remove("disabled");
    this.$el.classList.add("active");
    setTimeout(() => {
      if (this.props.role === "server") {
        this.$el.classList.remove("onload");
      }
    }, 1000);
    this.focus();
    this.props.onTitleChange();
    // Injecting preload css in webview to override some css rules
    (async () =>
      this.$el.insertCSS(
        fs.readFileSync(path.join(__dirname, "/../../css/preload.css"), "utf8"),
      ))();

    // Get customCSS again from config util to avoid warning user again
    this.customCSS = ConfigUtil.getConfigItem("customCSS");
    if (this.customCSS) {
      if (!fs.existsSync(this.customCSS)) {
        this.customCSS = null;
        ConfigUtil.setConfigItem("customCSS", null);

        const errorMessage = "The custom css previously set is deleted!";
        dialog.showErrorBox("custom css file deleted!", errorMessage);
        return;
      }

      (async () =>
        this.$el.insertCSS(
          fs.readFileSync(path.resolve(__dirname, this.customCSS), "utf8"),
        ))();
    }
  }

  focus(): void {
    // Focus Webview and it's contents when Window regain focus.
    const webContents = remote.webContents.fromId(this.$el.getWebContentsId());
    // HACK: webContents.isFocused() seems to be true even without the element
    // being in focus. So, we check against `document.activeElement`.
    if (webContents && this.$el !== document.activeElement) {
      // HACK: Looks like blur needs to be called on the previously focused
      // element to transfer focus correctly, in Electron v3.0.10
      // See https://github.com/electron/electron/issues/15718
      (document.activeElement as HTMLElement).blur();
      this.$el.focus();
      webContents.focus();
    }
  }

  hide(): void {
    this.$el.classList.add("disabled");
    this.$el.classList.remove("active");
  }

  load(): void {
    if (this.$el) {
      this.show();
    } else {
      this.init();
    }
  }

  zoomIn(): void {
    this.zoomFactor += 0.1;
    this.$el.setZoomFactor(this.zoomFactor);
  }

  zoomOut(): void {
    this.zoomFactor -= 0.1;
    this.$el.setZoomFactor(this.zoomFactor);
  }

  zoomActualSize(): void {
    this.zoomFactor = 1;
    this.$el.setZoomFactor(this.zoomFactor);
  }

  logOut(): void {
    ipcRenderer.sendTo(this.$el.getWebContentsId(), "logout");
  }

  showKeyboardShortcuts(): void {
    ipcRenderer.sendTo(this.$el.getWebContentsId(), "show-keyboard-shortcuts");
  }

  openDevTools(): void {
    this.$el.openDevTools();
  }

  back(): void {
    if (this.$el.canGoBack()) {
      this.$el.goBack();
      this.focus();
    }
  }

  canGoBackButton(): void {
    const $backButton = document.querySelector(
      "#actions-container #back-action",
    );
    if (this.$el.canGoBack()) {
      $backButton.classList.remove("disable");
    } else {
      $backButton.classList.add("disable");
    }
  }

  forward(): void {
    if (this.$el.canGoForward()) {
      this.$el.goForward();
    }
  }

  reload(): void {
    this.hide();
    // Shows the loading indicator till the webview is reloaded
    this.$webviewsContainer.remove("loaded");
    this.loading = true;
    this.props.switchLoading(true, this.props.url);
    this.$el.reload();
  }

  forceLoad(): void {
    this.init();
  }

  async send(channel: string, ...parameters: unknown[]): Promise<void> {
    await this.domReady;
    await this.$el.send(channel, ...parameters);
  }
}