/**
 * This module contains tools and helpers to open HelpScout "Beacon" -- a popup which may contain
 * an email form, chat, and help docs -- and to include info relevant to support requests.
 *
 * Usage:
 *    import {Beacon} from 'app/client/lib/helpScout';
 *    Beacon('open')
 *    Beacon('prefill', {...})
 * It takes care of initialization automatically.
 *
 * This is essentially a prettified typescript version of the snippet for the HelpScout Beacon
 * available under Beacon settings in HelpScout. It offers the API documented at
 * https://developer.helpscout.com/beacon-2/web/javascript-api/
 */

// tslint:disable:unified-signatures

import {logTelemetryEvent} from 'app/client/lib/telemetry';
import {AppModel} from 'app/client/models/AppModel';
import {reportWarning} from 'app/client/models/errors';
import {IAppError} from 'app/client/models/NotifyModel';
import {GristLoadConfig} from 'app/common/gristUrls';
import {timeFormat} from 'app/common/timeFormat';
import * as version from 'app/common/version';
import {dom} from 'grainjs';
import identity = require('lodash/identity');
import pickBy = require('lodash/pickBy');

export type BeaconCmd = 'init' | 'destroy' | 'open' | 'close' | 'toggle' | 'search' | 'suggest' |
  'article' | 'navigate' | 'identify' | 'prefill' | 'reset' | 'logout' | 'config' | 'on' | 'off' |
  'once' | 'event' | 'session-data';

export type BeaconRoute = '/ask/message/' | '/answers/';

export interface IUserObj {
  name?: string;
  email?: string;
  company?: string;
  jobTitle?: string;
  avatar?: string;
  signature?: string;
  [customKey: string]: string|number|boolean|null|undefined;
}

interface IFormObj {
  name?: string;
  email?: string;
  subject?: string;
  text?: string;
  fields?: Array<{id: number, value: string|number|boolean}>;
}

interface ISessionData {
  [key: string]: string;
}

interface ICallbackAttributes {
  id?: string;
  query?: string;
}

/**
 * This provides the HelpScout Beacon API, taking care of initializing Beacon on first use.
 */
export function Beacon(method: 'init', beaconId: string): void;
export function Beacon(method: 'search', query: string): void;
export function Beacon(method: 'suggest', articles?: string[]): void;
export function Beacon(method: 'article', articleId: string, options?: unknown): void;
export function Beacon(method: 'navigate', route: string): void;
export function Beacon(method: 'identify', userObj: IUserObj): void;
export function Beacon(method: 'prefill', formObj: IFormObj): void;
export function Beacon(method: 'config', configObj: object): void;
export function Beacon(method: 'on'|'once', event: string,
  callback: (attrs?: ICallbackAttributes) => void): void;
export function Beacon(method: 'off', event: string, callback?: () => void): void;
export function Beacon(method: 'session-data', data: ISessionData): void;
export function Beacon(method: BeaconCmd): void;
export function Beacon(method: BeaconCmd, options?: unknown, data?: unknown) {
  initBeacon();
  (window as any).Beacon(method, options, data);
}

// This is essentially what's done by the code snippet that HelpScout suggests to install in every
// page. In Grist app pages, we only load HelpScout code when the beacon is opened.
function _beacon(method: BeaconCmd, options?: unknown, data?: unknown) {
  _beacon.readyQueue.push({method, options, data});
}
_beacon.readyQueue = [] as unknown[];

function initBeacon(): void {
  if (!(window as any).Beacon) {
    const gristConfig: GristLoadConfig|undefined = (window as any).gristConfig;
    const beaconId = gristConfig && gristConfig.helpScoutBeaconId;
    if (beaconId) {
      (window as any).Beacon = _beacon;
      document.head.appendChild(dom('script',
        {
          type: 'text/javascript',
          src: 'https://beacon-v2.helpscout.net',
          async: true,
        },
        // Report when the beacon fails to load so that the user knows something is wrong, and we
        // have a log of the error. (Note: might not report all failures due to ad-blockers.)
        dom.on('error', (e) => {
          reportWarning("Support form failed to load. " +
            "Please email support@getgrist.com with questions instead.");
        }),
      ));
      _beacon('init', beaconId);
      _beacon('config', {display: {style: "manual"}});
    } else {
      (window as any).Beacon = () => null;
      reportWarning("Support form is not configured");
    }
  }
}

let lastOpenType: 'error' | 'message' = 'message';
let lastRoute: BeaconRoute|null = null;

/**
 * Helper to open a beacon, taking care of setting focus appropriately. Calls optional onOpen
 * callback when the beacon has opened.
 * If errors is given, prepares a form for submitting an error report, and includes stack traces
 * into the session-data.
 */
function _beaconOpen(userObj: IUserObj|null, options: IBeaconOpenOptions) {
  const {onOpen, errors} = options;

  // The beacon remembers its content, so reset it when switching between reporting errors and
  // sending a message.
  const openType = errors?.length ? 'error' : 'message';
  if (openType !== lastOpenType) {
    Beacon('reset');
    lastOpenType = openType;
  }

  const route: BeaconRoute = options.route || (errors?.length ? '/ask/message/' : '/answers/');
  // If beacon was and still is being opened for help articles, avoid the 'navigate' call
  // altogether, to keep the beacon at the last article it was on.
  const skipNav = (route === lastRoute && route === '/answers/');
  lastRoute = route;

  Beacon('once', 'open', () => {
    const iframe = document.querySelector('#beacon-container iframe') as HTMLIFrameElement;
    if (iframe) { iframe.focus(); }
    if (onOpen) { onOpen(); }
  });
  // Fix base-href tag when opening an article.
  Beacon('once', 'article-viewed', () => fixBeaconBaseHref());
  // We duplicate this check for 'ready' event, because 'open' and 'article-viewed' events don't
  // trigger on page reload when a beacon article is already open (seems to be a HelpScout bug).
  Beacon('once', 'ready', () => fixBeaconBaseHref());

  Beacon('once', 'close', () => {
    const iframe = document.querySelector('#beacon-container iframe') as HTMLIFrameElement;
    if (iframe) { iframe.blur(); }
    Beacon('off', 'article-viewed');
  });
  if (userObj) {
    Beacon('identify', userObj);
  }

  const attrs: ISessionData = {};
  if (errors?.length) {
    // If sending errors, prefill part of the message (the user sees this and can add to it), and
    // include more detailed errors with stack traces into session-data.
    const messages = errors.map(({error, timestamp}) =>
      (timeFormat('T', new Date(timestamp)) + ' ' + error.message));
    const lastMessage = errors.length > 0 ? errors[errors.length - 1].error.message : '';
    const prefill: IFormObj = {
      subject: `Application Error: ${lastMessage}`.slice(0, 250), // subject has max-length of 250
      text: `\n-- Include your description above --\nErrors encountered:\n${messages.join('\n')}\n`,
    };
    Beacon('prefill', prefill);
    Beacon('config', {messaging: {contactForm: {showSubject: false}}});

    errors.forEach(({error, timestamp}, i) => {
      attrs[`error-${i}`] =  timeFormat('D T', new Date(timestamp)) + ' ' + error.message;
      if (error.stack) {
        attrs[`error-${i}-stack`] = JSON.stringify(error.stack.trim().split('\n'));
      }
    });
  } else {
    Beacon('config', {messaging: {contactForm: {showSubject: true}}});
  }

  Beacon('session-data', {
    'Grist Version': `${version.version} (${version.gitcommit})`,
    ...attrs,
  });
  Beacon('open');
  if (!skipNav) {
    Beacon('navigate', route);
  }

  Beacon('once', 'open', () => logTelemetryEvent('beaconOpen'));
  Beacon('on', 'article-viewed', (article) => logTelemetryEvent('beaconArticleViewed', {
    full: {articleId: article!.id},
  }));
  Beacon('on', 'email-sent', () => logTelemetryEvent('beaconEmailSent'));
  Beacon('on', 'search', (search) => logTelemetryEvent('beaconSearch', {
    full: {searchQuery: search!.query},
  }));
}

function fixBeaconBaseHref() {
  // HelpScout creates an iframe with an empty 'src' attribute, then writes to it. In such an
  // iframe, different browsers interpret relative links differently: Chrome's are relative to
  // the parent page's URL; Firefox's are relative to the parent page's <base href>.
  //
  // Here we set a <base href> explicitly in the iframe to get consistent behavior of links
  // relative to the top page's URL (HelpScout then seems to handle clicks on them correctly).
  const iframe = document.querySelector('#beacon-container iframe') as HTMLIFrameElement;
  const iframeDoc = iframe?.contentDocument;
  if (iframeDoc && !iframeDoc.querySelector('head > base')) {
    iframeDoc.head.appendChild(dom('base', {href: ''}));
  }
}

export interface IBeaconOpenOptions {
  appModel: AppModel|null;
  includeAppErrors?: boolean;
  onOpen?: () => void;
  errors?: IAppError[];
  route?: BeaconRoute;
}

/**
 * Open the helpScout beacon to send us a message. Calls optional onOpen callback when the beacon
 * has opened. The topAppModel is used to get the current user.
 *
 * If includeAppErrors or errors is set, the beacon will open to submit an error report. With
 * includeAppErrors, it will include stack traces of errors in the notifier into the session-data.
 * If errors is set, it will include the specified errors.
 */
export function beaconOpenMessage(options: IBeaconOpenOptions) {
  const app = options.appModel;
  const errors = options.errors || [];
  if (options.includeAppErrors && app) {
    errors.push(...app.notifier.getFullAppErrors());
  }
  _beaconOpen(getBeaconUserObj(app), {...options, errors});
}


function getBeaconUserObj(appModel: AppModel|null): IUserObj|null {
  if (!appModel) { return null; }

  // ActiveSessionInfo["user"] includes optional helpScoutSignature too.
  const user = appModel.currentValidUser;

  // For anon user, don't attempt to identify anything. Even the "company" field (when anon on a
  // team doc) isn't useful, because the user may be external to the company.
  if (!user) { return null; }

  // Use the company name only when it's not a personal org. Otherwise, it adds no information and
  // overrides more useful company name gleaned by HelpScout from the web.
  const org = appModel.currentOrg;
  const company = org && !org.owner ? appModel.currentOrgName : undefined;

  return pickBy({
    name: user.name,
    email: user.email,
    company,
    avatar: user.picture,
    signature: user.helpScoutSignature,
  }, identity);
}