/**
 * @license
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import '../../../scripts/bundled-polymer.js';

import {Polymer} from '@polymer/polymer/lib/legacy/polymer-fn.js';

// Latency reporting constants.
const TIMING = {
  TYPE: 'timing-report',
  CATEGORY_UI_LATENCY: 'UI Latency',
  CATEGORY_RPC: 'RPC Timing',
  // Reported events - alphabetize below.
  APP_STARTED: 'App Started',
};

// Plugin-related reporting constants.
const PLUGINS = {
  TYPE: 'lifecycle',
  // Reported events - alphabetize below.
  INSTALLED: 'Plugins installed',
};

// Chrome extension-related reporting constants.
const EXTENSION = {
  TYPE: 'lifecycle',
  // Reported events - alphabetize below.
  DETECTED: 'Extension detected',
};

// Navigation reporting constants.
const NAVIGATION = {
  TYPE: 'nav-report',
  CATEGORY: 'Location Changed',
  PAGE: 'Page',
};

const ERROR = {
  TYPE: 'error',
  CATEGORY: 'exception',
};

const ERROR_DIALOG = {
  TYPE: 'error',
  CATEGORY: 'Error Dialog',
};

const TIMER = {
  CHANGE_DISPLAYED: 'ChangeDisplayed',
  CHANGE_LOAD_FULL: 'ChangeFullyLoaded',
  DASHBOARD_DISPLAYED: 'DashboardDisplayed',
  DIFF_VIEW_CONTENT_DISPLAYED: 'DiffViewOnlyContent',
  DIFF_VIEW_DISPLAYED: 'DiffViewDisplayed',
  DIFF_VIEW_LOAD_FULL: 'DiffViewFullyLoaded',
  FILE_LIST_DISPLAYED: 'FileListDisplayed',
  PLUGINS_LOADED: 'PluginsLoaded',
  STARTUP_CHANGE_DISPLAYED: 'StartupChangeDisplayed',
  STARTUP_CHANGE_LOAD_FULL: 'StartupChangeFullyLoaded',
  STARTUP_DASHBOARD_DISPLAYED: 'StartupDashboardDisplayed',
  STARTUP_DIFF_VIEW_CONTENT_DISPLAYED: 'StartupDiffViewOnlyContent',
  STARTUP_DIFF_VIEW_DISPLAYED: 'StartupDiffViewDisplayed',
  STARTUP_DIFF_VIEW_LOAD_FULL: 'StartupDiffViewFullyLoaded',
  STARTUP_FILE_LIST_DISPLAYED: 'StartupFileListDisplayed',
  WEB_COMPONENTS_READY: 'WebComponentsReady',
  METRICS_PLUGIN_LOADED: 'MetricsPluginLoaded',
};

const STARTUP_TIMERS = {};
STARTUP_TIMERS[TIMER.PLUGINS_LOADED] = 0;
STARTUP_TIMERS[TIMER.METRICS_PLUGIN_LOADED] = 0;
STARTUP_TIMERS[TIMER.STARTUP_CHANGE_DISPLAYED] = 0;
STARTUP_TIMERS[TIMER.STARTUP_CHANGE_LOAD_FULL] = 0;
STARTUP_TIMERS[TIMER.STARTUP_DASHBOARD_DISPLAYED] = 0;
STARTUP_TIMERS[TIMER.STARTUP_DIFF_VIEW_CONTENT_DISPLAYED] = 0;
STARTUP_TIMERS[TIMER.STARTUP_DIFF_VIEW_DISPLAYED] = 0;
STARTUP_TIMERS[TIMER.STARTUP_DIFF_VIEW_LOAD_FULL] = 0;
STARTUP_TIMERS[TIMER.STARTUP_FILE_LIST_DISPLAYED] = 0;
STARTUP_TIMERS[TIMING.APP_STARTED] = 0;
// WebComponentsReady timer is triggered from gr-router.
STARTUP_TIMERS[TIMER.WEB_COMPONENTS_READY] = 0;

const INTERACTION_TYPE = 'interaction';

const DRAFT_ACTION_TIMER = 'TimeBetweenDraftActions';
const DRAFT_ACTION_TIMER_MAX = 2 * 60 * 1000; // 2 minutes.

let pending = [];
let slowRpcList = [];
const SLOW_RPC_THRESHOLD = 500;

// Variables that hold context info in global scope
let reportRepoName = undefined;

const onError = function(oldOnError, msg, url, line, column, error) {
  if (oldOnError) {
    oldOnError(msg, url, line, column, error);
  }
  if (error) {
    line = line || error.lineNumber;
    column = column || error.columnNumber;
    let shortenedErrorStack = msg;
    if (error.stack) {
      const errorStackLines = error.stack.split('\n');
      shortenedErrorStack = errorStackLines.slice(0,
          Math.min(3, errorStackLines.length)).join('\n');
    }
    msg = shortenedErrorStack || error.toString();
  }
  const payload = {
    url,
    line,
    column,
    error,
  };
  GrReporting.prototype.reporter(ERROR.TYPE, ERROR.CATEGORY, msg, payload);
  return true;
};

const catchErrors = function(opt_context) {
  const context = opt_context || window;
  context.onerror = onError.bind(null, context.onerror);
  context.addEventListener('unhandledrejection', e => {
    const msg = e.reason.message;
    const payload = {
      error: e.reason,
    };
    GrReporting.prototype.reporter(ERROR.TYPE, ERROR.CATEGORY, msg, payload);
  });
};
catchErrors();

// PerformanceObserver interface is a browser API.
if (window.PerformanceObserver) {
  const supportedEntryTypes = PerformanceObserver.supportedEntryTypes || [];
  // Safari doesn't support longtask yet
  if (supportedEntryTypes.includes('longtask')) {
    const catchLongJsTasks = new PerformanceObserver(list => {
      for (const task of list.getEntries()) {
        // We are interested in longtask longer than 200 ms (default is 50 ms)
        if (task.duration > 200) {
          GrReporting.prototype.reporter(TIMING.TYPE,
              TIMING.CATEGORY_UI_LATENCY, `Task ${task.name}`,
              Math.round(task.duration), {}, false);
        }
      }
    });
    catchLongJsTasks.observe({entryTypes: ['longtask']});
  }
}

document.addEventListener('visibilitychange', () => {
  const eventName = `Visibility changed to ${document.visibilityState}`;
  GrReporting.prototype.reporter(INTERACTION_TYPE, undefined, eventName,
      undefined, {}, true);
});

// The Polymer pass of JSCompiler requires this to be reassignable
// eslint-disable-next-line prefer-const
let GrReporting = Polymer({
  is: 'gr-reporting',

  properties: {
    category: String,

    _baselines: {
      type: Object,
      value: STARTUP_TIMERS, // Shared across all instances.
    },

    _timers: {
      type: Object,
      value: {timeBetweenDraftActions: null}, // Shared across all instances.
    },
  },

  get performanceTiming() {
    return window.performance.timing;
  },

  get slowRpcSnapshot() {
    return slowRpcList.slice();
  },

  now() {
    return Math.round(window.performance.now());
  },

  _arePluginsLoaded() {
    return this._baselines &&
      !this._baselines.hasOwnProperty(TIMER.PLUGINS_LOADED);
  },

  _isMetricsPluginLoaded() {
    return this._arePluginsLoaded() || this._baselines &&
      !this._baselines.hasOwnProperty(TIMER.METRICS_PLUGIN_LOADED);
  },

  /**
   * Reporter reports events. Events will be queued if metrics plugin is not
   * yet installed.
   *
   * @param {string} type
   * @param {string} category
   * @param {string} eventName
   * @param {string|number} eventValue
   * @param {Object} eventDetails
   * @param {boolean|undefined} opt_noLog If true, the event will not be
   *     logged to the JS console.
   */
  reporter(type, category, eventName, eventValue, eventDetails, opt_noLog) {
    const eventInfo = this._createEventInfo(type, category,
        eventName, eventValue, eventDetails);
    if (type === ERROR.TYPE && category === ERROR.CATEGORY) {
      console.error(eventValue && eventValue.error || eventName);
    }

    // We report events immediately when metrics plugin is loaded
    if (this._isMetricsPluginLoaded() && !pending.length) {
      this._reportEvent(eventInfo, opt_noLog);
    } else {
      // We cache until metrics plugin is loaded
      pending.push([eventInfo, opt_noLog]);
      if (this._isMetricsPluginLoaded()) {
        pending.forEach(([eventInfo, opt_noLog]) => {
          this._reportEvent(eventInfo, opt_noLog);
        });
        pending = [];
      }
    }
  },

  _reportEvent(eventInfo, opt_noLog) {
    const {type, value, name} = eventInfo;
    document.dispatchEvent(new CustomEvent(type, {detail: eventInfo}));
    if (opt_noLog) { return; }
    if (type !== ERROR.TYPE) {
      if (value !== undefined) {
        console.log(`Reporting: ${name}: ${value}`);
      } else {
        console.log(`Reporting: ${name}`);
      }
    }
  },

  _createEventInfo(type, category, name, value, eventDetails) {
    const eventInfo = {
      type,
      category,
      name,
      value,
      eventStart: this.now(),
    };

    if (typeof(eventDetails) === 'object' &&
      Object.entries(eventDetails).length !== 0) {
      eventInfo.eventDetails = JSON.stringify(eventDetails);
    }
    if (reportRepoName) {
      eventInfo.repoName = reportRepoName;
    }
    const isInBackgroundTab = document.visibilityState === 'hidden';
    if (isInBackgroundTab !== undefined) {
      eventInfo.inBackgroundTab = isInBackgroundTab;
    }

    return eventInfo;
  },

  /**
   * User-perceived app start time, should be reported when the app is ready.
   */
  appStarted() {
    this.timeEnd(TIMING.APP_STARTED);
    this._reportNavResTimes();
  },

  /**
   * Browser's navigation and resource timings
   */
  _reportNavResTimes() {
    const perfEvents = Object.keys(this.performanceTiming.toJSON());
    perfEvents.forEach(
        eventName => this._reportPerformanceTiming(eventName)
    );
  },

  _reportPerformanceTiming(eventName, eventDetails) {
    const eventTiming = this.performanceTiming[eventName];
    if (eventTiming > 0) {
      const elapsedTime = eventTiming -
          this.performanceTiming.navigationStart;
      // NavResTime - Navigation and resource timings.
      this.reporter(TIMING.TYPE, TIMING.CATEGORY_UI_LATENCY,
          `NavResTime - ${eventName}`, elapsedTime, eventDetails, true);
    }
  },

  beforeLocationChanged() {
    for (const prop of Object.keys(this._baselines)) {
      delete this._baselines[prop];
    }
    this.time(TIMER.CHANGE_DISPLAYED);
    this.time(TIMER.CHANGE_LOAD_FULL);
    this.time(TIMER.DASHBOARD_DISPLAYED);
    this.time(TIMER.DIFF_VIEW_CONTENT_DISPLAYED);
    this.time(TIMER.DIFF_VIEW_DISPLAYED);
    this.time(TIMER.DIFF_VIEW_LOAD_FULL);
    this.time(TIMER.FILE_LIST_DISPLAYED);
    reportRepoName = undefined;
    // reset slow rpc list since here start page loads which report these rpcs
    slowRpcList = [];
  },

  locationChanged(page) {
    this.reporter(
        NAVIGATION.TYPE, NAVIGATION.CATEGORY, NAVIGATION.PAGE, page);
  },

  dashboardDisplayed() {
    if (this._baselines.hasOwnProperty(TIMER.STARTUP_DASHBOARD_DISPLAYED)) {
      this.timeEnd(TIMER.STARTUP_DASHBOARD_DISPLAYED, {rpcList:
        this.slowRpcSnapshot});
    } else {
      this.timeEnd(TIMER.DASHBOARD_DISPLAYED, {rpcList:
        this.slowRpcSnapshot});
    }
  },

  changeDisplayed() {
    if (this._baselines.hasOwnProperty(TIMER.STARTUP_CHANGE_DISPLAYED)) {
      this.timeEnd(TIMER.STARTUP_CHANGE_DISPLAYED, {rpcList:
        this.slowRpcSnapshot});
    } else {
      this.timeEnd(TIMER.CHANGE_DISPLAYED, {rpcList:
        this.slowRpcSnapshot});
    }
  },

  changeFullyLoaded() {
    if (this._baselines.hasOwnProperty(TIMER.STARTUP_CHANGE_LOAD_FULL)) {
      this.timeEnd(TIMER.STARTUP_CHANGE_LOAD_FULL);
    } else {
      this.timeEnd(TIMER.CHANGE_LOAD_FULL);
    }
  },

  diffViewDisplayed() {
    if (this._baselines.hasOwnProperty(TIMER.STARTUP_DIFF_VIEW_DISPLAYED)) {
      this.timeEnd(TIMER.STARTUP_DIFF_VIEW_DISPLAYED, {rpcList:
        this.slowRpcSnapshot});
    } else {
      this.timeEnd(TIMER.DIFF_VIEW_DISPLAYED, {rpcList:
        this.slowRpcSnapshot});
    }
  },

  diffViewFullyLoaded() {
    if (this._baselines.hasOwnProperty(TIMER.STARTUP_DIFF_VIEW_LOAD_FULL)) {
      this.timeEnd(TIMER.STARTUP_DIFF_VIEW_LOAD_FULL);
    } else {
      this.timeEnd(TIMER.DIFF_VIEW_LOAD_FULL);
    }
  },

  diffViewContentDisplayed() {
    if (this._baselines.hasOwnProperty(
        TIMER.STARTUP_DIFF_VIEW_CONTENT_DISPLAYED)) {
      this.timeEnd(TIMER.STARTUP_DIFF_VIEW_CONTENT_DISPLAYED);
    } else {
      this.timeEnd(TIMER.DIFF_VIEW_CONTENT_DISPLAYED);
    }
  },

  fileListDisplayed() {
    if (this._baselines.hasOwnProperty(TIMER.STARTUP_FILE_LIST_DISPLAYED)) {
      this.timeEnd(TIMER.STARTUP_FILE_LIST_DISPLAYED);
    } else {
      this.timeEnd(TIMER.FILE_LIST_DISPLAYED);
    }
  },

  reportExtension(name) {
    this.reporter(EXTENSION.TYPE, EXTENSION.DETECTED, name);
  },

  pluginLoaded(name) {
    if (name.startsWith('metrics-')) {
      this.timeEnd(TIMER.METRICS_PLUGIN_LOADED);
    }
  },

  pluginsLoaded(pluginsList) {
    this.timeEnd(TIMER.PLUGINS_LOADED);
    this.reporter(
        PLUGINS.TYPE, PLUGINS.INSTALLED, PLUGINS.INSTALLED, undefined,
        {pluginsList: pluginsList || []}, true);
  },

  /**
   * Reset named timer.
   */
  time(name) {
    this._baselines[name] = this.now();
    window.performance.mark(`${name}-start`);
  },

  /**
   * Finish named timer and report it to server.
   */
  timeEnd(name, eventDetails) {
    if (!this._baselines.hasOwnProperty(name)) { return; }
    const baseTime = this._baselines[name];
    delete this._baselines[name];
    this._reportTiming(name, this.now() - baseTime, eventDetails);

    // Finalize the interval. Either from a registered start mark or
    // the navigation start time (if baseTime is 0).
    if (baseTime !== 0) {
      window.performance.measure(name, `${name}-start`);
    } else {
      // Microsft Edge does not handle the 2nd param correctly
      // (if undefined).
      window.performance.measure(name);
    }
  },

  /**
   * Reports just line timeEnd, but additionally reports an average given a
   * denominator and a separate reporiting name for the average.
   *
   * @param {string} name Timing name.
   * @param {string} averageName Average timing name.
   * @param {number} denominator Number by which to divide the total to
   *     compute the average.
   */
  timeEndWithAverage(name, averageName, denominator) {
    if (!this._baselines.hasOwnProperty(name)) { return; }
    const baseTime = this._baselines[name];
    this.timeEnd(name);

    // Guard against division by zero.
    if (!denominator) { return; }
    const time = this.now() - baseTime;
    this._reportTiming(averageName, time / denominator);
  },

  /**
   * Send a timing report with an arbitrary time value.
   *
   * @param {string} name Timing name.
   * @param {number} time The time to report as an integer of milliseconds.
   * @param {Object} eventDetails non sensitive details
   */
  _reportTiming(name, time, eventDetails) {
    this.reporter(TIMING.TYPE, TIMING.CATEGORY_UI_LATENCY, name, time,
        eventDetails);
  },

  /**
   * Get a timer object to for reporing a user timing. The start time will be
   * the time that the object has been created, and the end time will be the
   * time that the "end" method is called on the object.
   *
   * @param {string} name Timing name.
   * @returns {!Object} The timer object.
   */
  getTimer(name) {
    let called = false;
    let start;
    let max = null;

    const timer = {

      // Clear the timer and reset the start time.
      reset: () => {
        called = false;
        start = this.now();
        return timer;
      },

      // Stop the timer and report the intervening time.
      end: () => {
        if (called) {
          throw new Error(`Timer for "${name}" already ended.`);
        }
        called = true;
        const time = this.now() - start;

        // If a maximum is specified and the time exceeds it, do not report.
        if (max && time > max) { return timer; }

        this._reportTiming(name, time);
        return timer;
      },

      // Set a maximum reportable time. If a maximum is set and the timer is
      // ended after the specified amount of time, the value is not reported.
      withMaximum(maximum) {
        max = maximum;
        return timer;
      },
    };

    // The timer is initialized to its creation time.
    return timer.reset();
  },

  /**
   * Log timing information for an RPC.
   *
   * @param {string} anonymizedUrl The URL of the RPC with tokens obfuscated.
   * @param {number} elapsed The time elapsed of the RPC.
   */
  reportRpcTiming(anonymizedUrl, elapsed) {
    this.reporter(TIMING.TYPE, TIMING.CATEGORY_RPC, 'RPC-' + anonymizedUrl,
        elapsed, {}, true);
    if (elapsed >= SLOW_RPC_THRESHOLD) {
      slowRpcList.push({anonymizedUrl, elapsed});
    }
  },

  reportInteraction(eventName, details) {
    this.reporter(INTERACTION_TYPE, this.category, eventName, undefined,
        details, true);
  },

  /**
   * A draft interaction was started. Update the time-betweeen-draft-actions
   * timer.
   */
  recordDraftInteraction() {
    // If there is no timer defined, then this is the first interaction.
    // Set up the timer so that it's ready to record the intervening time when
    // called again.
    const timer = this._timers.timeBetweenDraftActions;
    if (!timer) {
      // Create a timer with a maximum length.
      this._timers.timeBetweenDraftActions = this.getTimer(DRAFT_ACTION_TIMER)
          .withMaximum(DRAFT_ACTION_TIMER_MAX);
      return;
    }

    // Mark the time and reinitialize the timer.
    timer.end().reset();
  },

  reportErrorDialog(message) {
    this.reporter(ERROR_DIALOG.TYPE, ERROR_DIALOG.CATEGORY,
        'ErrorDialog: ' + message, {error: new Error(message)});
  },

  setRepoName(repoName) {
    reportRepoName = repoName;
  },
});

window.GrReporting = GrReporting;
// Expose onerror installation so it would be accessible from tests.
window.GrReporting._catchErrors = catchErrors;
window.GrReporting.STARTUP_TIMERS = Object.assign({}, STARTUP_TIMERS);