/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

import { Log } from "resource://gre/modules/Log.sys.mjs";
import { TelemetryUtils } from "resource://gre/modules/TelemetryUtils.sys.mjs";
import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";

const lazy = {};

ChromeUtils.defineESModuleGetters(lazy, {
  AddonManagerPrivate: "resource://gre/modules/AddonManager.sys.mjs",
  NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
  TelemetryController: "resource://gre/modules/TelemetryController.sys.mjs",
  TelemetryEnvironment: "resource://gre/modules/TelemetryEnvironment.sys.mjs",
  TelemetryReportingPolicy:
    "resource://gre/modules/TelemetryReportingPolicy.sys.mjs",
  TelemetryScheduler: "resource://gre/modules/TelemetryScheduler.sys.mjs",
  TelemetryStorage: "resource://gre/modules/TelemetryStorage.sys.mjs",
});

const Utils = TelemetryUtils;

// When modifying the payload in incompatible ways, please bump this version number
const PAYLOAD_VERSION = 4;
const PING_TYPE_MAIN = "main";
const PING_TYPE_SAVED_SESSION = "saved-session";

const REASON_ABORTED_SESSION = "aborted-session";
const REASON_DAILY = "daily";
const REASON_SAVED_SESSION = "saved-session";
const REASON_GATHER_PAYLOAD = "gather-payload";
const REASON_TEST_PING = "test-ping";
const REASON_ENVIRONMENT_CHANGE = "environment-change";
const REASON_SHUTDOWN = "shutdown";

const ENVIRONMENT_CHANGE_LISTENER = "TelemetrySession::onEnvironmentChange";

const MIN_SUBSESSION_LENGTH_MS =
  Services.prefs.getIntPref("toolkit.telemetry.minSubsessionLength", 5 * 60) *
  1000;

const LOGGER_NAME = "Toolkit.Telemetry";
const LOGGER_PREFIX =
  "TelemetrySession" + (Utils.isContentProcess ? "#content::" : "::");

// Whether the FHR/Telemetry unification features are enabled.
// Changing this pref requires a restart.
const IS_UNIFIED_TELEMETRY = Services.prefs.getBoolPref(
  TelemetryUtils.Preferences.Unified,
  false
);

function generateUUID() {
  let str = Services.uuid.generateUUID().toString();
  // strip {}
  return str.substring(1, str.length - 1);
}

/**
 * This is a policy object used to override behavior for testing.
 */
export var Policy = {
  now: () => new Date(),
  monotonicNow: Utils.monotonicNow,
  generateSessionUUID: () => generateUUID(),
  generateSubsessionUUID: () => generateUUID(),
};

/**
 * Get the ping type based on the payload.
 *
 * @param {object} aPayload The ping payload.
 * @return {string} A string representing the ping type.
 */
function getPingType(aPayload) {
  // To remain consistent with server-side ping handling, set "saved-session" as the ping
  // type for "saved-session" payload reasons.
  if (aPayload.info.reason == REASON_SAVED_SESSION) {
    return PING_TYPE_SAVED_SESSION;
  }

  return PING_TYPE_MAIN;
}

/**
 * Annotate the current session ID with the crash reporter to map potential
 * crash pings with the related main ping.
 */
function annotateCrashReport(sessionId) {
  try {
    Services.appinfo.annotateCrashReport("TelemetrySessionId", sessionId);
  } catch (e) {
    // Ignore errors when crash reporting is disabled
  }
}

/**
 * Read current process I/O counters.
 */
var processInfo = {
  _initialized: false,
  _IO_COUNTERS: null,
  _kernel32: null,
  _GetProcessIoCounters: null,
  _GetCurrentProcess: null,
  getCounters() {
    let isWindows = "@mozilla.org/windows-registry-key;1" in Cc;
    if (isWindows) {
      return this.getCounters_Windows();
    }
    return null;
  },
  getCounters_Windows() {
    if (!this._initialized) {
      var { ctypes } = ChromeUtils.importESModule(
        "resource://gre/modules/ctypes.sys.mjs"
      );
      this._IO_COUNTERS = new ctypes.StructType("IO_COUNTERS", [
        { readOps: ctypes.unsigned_long_long },
        { writeOps: ctypes.unsigned_long_long },
        { otherOps: ctypes.unsigned_long_long },
        { readBytes: ctypes.unsigned_long_long },
        { writeBytes: ctypes.unsigned_long_long },
        { otherBytes: ctypes.unsigned_long_long },
      ]);
      try {
        this._kernel32 = ctypes.open("Kernel32.dll");
        this._GetProcessIoCounters = this._kernel32.declare(
          "GetProcessIoCounters",
          ctypes.winapi_abi,
          ctypes.bool, // return
          ctypes.voidptr_t, // hProcess
          this._IO_COUNTERS.ptr
        ); // lpIoCounters
        this._GetCurrentProcess = this._kernel32.declare(
          "GetCurrentProcess",
          ctypes.winapi_abi,
          ctypes.voidptr_t
        ); // return
        this._initialized = true;
      } catch (err) {
        return null;
      }
    }
    let io = new this._IO_COUNTERS();
    if (!this._GetProcessIoCounters(this._GetCurrentProcess(), io.address())) {
      return null;
    }
    return [parseInt(io.readBytes), parseInt(io.writeBytes)];
  },
};

export var TelemetrySession = Object.freeze({
  /**
   * Send a ping to a test server. Used only for testing.
   */
  testPing() {
    return Impl.testPing();
  },
  /**
   * Returns the current telemetry payload.
   *
   * @param reason Optional, the reason to trigger the payload.
   * @param clearSubsession Optional, whether to clear subsession specific data.
   * @returns Object
   */
  getPayload(reason, clearSubsession = false) {
    return Impl.getPayload(reason, clearSubsession);
  },
  /**
   * Save the session state to a pending file.
   * Used only for testing purposes.
   */
  testSavePendingPing() {
    return Impl.testSavePendingPing();
  },
  /**
   * Collect and store information about startup.
   */
  gatherStartup() {
    return Impl.gatherStartup();
  },
  /**
   * Inform the ping which AddOns are installed.
   *
   * @param aAddOns - The AddOns.
   */
  setAddOns(aAddOns) {
    return Impl.setAddOns(aAddOns);
  },
  /**
   * Descriptive metadata
   *
   * @param  reason
   *         The reason for the telemetry ping, this will be included in the
   *         returned metadata,
   * @return The metadata as a JS object
   */
  getMetadata(reason) {
    return Impl.getMetadata(reason);
  },

  /**
   * Reset the subsession and profile subsession counter.
   * This should only be called when the profile should be considered completely new,
   * e.g. after opting out of sending Telemetry
   */
  resetSubsessionCounter() {
    Impl._subsessionCounter = 0;
    Impl._profileSubsessionCounter = 0;
  },

  /**
   * Used only for testing purposes.
   */
  testReset() {
    Impl._newProfilePingSent = false;
    Impl._sessionId = null;
    Impl._subsessionId = null;
    Impl._previousSessionId = null;
    Impl._previousSubsessionId = null;
    Impl._subsessionCounter = 0;
    Impl._profileSubsessionCounter = 0;
    Impl._subsessionStartActiveTicks = 0;
    Impl._sessionActiveTicks = 0;
    Impl._isUserActive = true;
    Impl._isUserActiveNonSynthesized = true;
    Impl._consecutiveActiveTicks = 0;
    Impl._consecutiveActiveTicksNonSynthesized = 0;
    Impl._inactiveTimerId = null;
    Impl._inactiveTimerIdNonSynthesized = null;
    Impl._subsessionStartTimeMonotonic = 0;
    Impl._lastEnvironmentChangeDate = Policy.monotonicNow();
    this.testUninstall();
  },
  /**
   * Triggers shutdown of the module.
   */
  shutdown() {
    return Impl.shutdownChromeProcess();
  },
  /**
   * Used only for testing purposes.
   */
  testUninstall() {
    try {
      Impl.uninstall();
    } catch (ex) {
      // Ignore errors
    }
  },
  /**
   * Lightweight init function, called as soon as Firefox starts.
   */
  earlyInit(aTesting = false) {
    return Impl.earlyInit(aTesting);
  },
  /**
   * Does the "heavy" Telemetry initialization later on, so we
   * don't impact startup performance.
   *
   * @return {Promise} Resolved when the initialization completes.
   */
  delayedInit() {
    return Impl.delayedInit();
  },
  /**
   * Send a notification.
   */
  observe(aSubject, aTopic, aData) {
    return Impl.observe(aSubject, aTopic, aData);
  },
  /**
   * Marks the "new-profile" ping as sent in the telemetry state file.
   *
   * @return {Promise} A promise resolved when the new telemetry state is saved to disk.
   */
  markNewProfilePingSent() {
    return Impl.markNewProfilePingSent();
  },
  /**
   * Returns if the "new-profile" ping has ever been sent for this profile.
   * Please note that the returned value is trustworthy only after the delayed setup.
   *
   * @return {boolean} True if the new profile ping was sent on this profile,
   *         false otherwise.
   */
  get newProfilePingSent() {
    return Impl._newProfilePingSent;
  },

  saveAbortedSessionPing(aProvidedPayload) {
    return Impl._saveAbortedSessionPing(aProvidedPayload);
  },

  sendDailyPing() {
    return Impl._sendDailyPing();
  },

  testOnEnvironmentChange(...args) {
    return Impl._onEnvironmentChange(...args);
  },
});

var Impl = {
  _initialized: false,
  _logger: null,
  _slowSQLStartup: {},
  // The activity state for the user. If false, don't count the next
  // active tick. Otherwise, increment the active ticks as usual.
  _isUserActive: true,
  // Like _isUserActive, but only tracks non-synthesized events. Used to record
  // the corrected active tick (active_ticks_non_synthesized) side-by-side with
  // the legacy active tick.
  _isUserActiveNonSynthesized: true,
  // Length of the current uninterrupted run of active ticks. Recorded as a
  // sample into the consecutiveActiveTicks distribution when the run ends
  // (i.e. the user goes inactive), then reset.
  _consecutiveActiveTicks: 0,
  // Like _consecutiveActiveTicks, but for the non-synthesized stream.
  _consecutiveActiveTicksNonSynthesized: 0,
  // Glean timing_distribution timer id for the inactive period currently in
  // progress, or null if the user is active. Set when the user goes inactive
  // and stopped (accumulated) when activity resumes.
  _inactiveTimerId: null,
  // Like _inactiveTimerId, but for the non-synthesized stream.
  _inactiveTimerIdNonSynthesized: null,
  _startupIO: {},
  // The previous build ID, if this is the first run with a new build.
  // Null if this is the first run, or the previous build ID is unknown.
  _previousBuildId: null,
  // Unique id that identifies this session so the server can cope with duplicate
  // submissions, orphaning and other oddities. The id is shared across subsessions.
  _sessionId: null,
  // Random subsession id.
  _subsessionId: null,
  // Session id of the previous session, null on first run.
  _previousSessionId: null,
  // Subsession id of the previous subsession (even if it was in a different session),
  // null on first run.
  _previousSubsessionId: null,
  // The running no. of subsessions since the start of the browser session
  _subsessionCounter: 0,
  // The running no. of all subsessions for the whole profile life time
  _profileSubsessionCounter: 0,
  // Date of the last session split
  _subsessionStartDate: null,
  // Start time of the current subsession using a monotonic clock for the subsession
  // length measurements.
  _subsessionStartTimeMonotonic: 0,
  // The active ticks counted when the subsession starts
  _subsessionStartActiveTicks: 0,
  // Active ticks in the whole session.
  _sessionActiveTicks: 0,
  // A task performing delayed initialization of the chrome process
  _delayedInitTask: null,
  _testing: false,
  // An accumulator of total memory across all processes. Only valid once the final child reports.
  _lastEnvironmentChangeDate: 0,
  // We save whether the "new-profile" ping was sent yet, to
  // survive profile refresh and migrations.
  _newProfilePingSent: false,
  // Keep track of the active observers
  _observedTopics: new Set(),
  _earlyObserversRegistered: false,
  _delayedObserversRegistered: false,

  addObserver(aTopic) {
    Services.obs.addObserver(this, aTopic);
    this._observedTopics.add(aTopic);
  },

  removeObserver(aTopic) {
    Services.obs.removeObserver(this, aTopic);
    this._observedTopics.delete(aTopic);
  },

  get _log() {
    if (!this._logger) {
      this._logger = Log.repository.getLoggerWithMessagePrefix(
        LOGGER_NAME,
        LOGGER_PREFIX
      );
    }
    return this._logger;
  },

  /**
   * Gets a series of simple measurements (counters). At the moment, this
   * only returns startup data from nsIAppStartup.getStartupInfo().
   *
   * @param {boolean} isSubsession True if this is a subsession, false otherwise.
   * @param {boolean} clearSubsession True if a new subsession is being started, false otherwise.
   *
   * @return simple measurements as a dictionary.
   */
  getSimpleMeasurements: function getSimpleMeasurements(
    forSavedSession,
    isSubsession,
    clearSubsession
  ) {
    // Only activeTicks, blankWindowShown, firstPaint, main, sessionRestored,
    // and totalTime are recognized by the pipeline, so only report those.

    // Supplies `process` for calculations, `firstPaint`, `main`,
    // `sessionRestored`.
    let si = Services.startup.getStartupInfo();

    // Measurements common to chrome and content processes.
    let elapsedTime = Date.now() - si.process;
    var ret = {
      totalTime: Math.round(elapsedTime / 1000), // totalTime, in seconds
    };

    // Look for app-specific timestamps
    var appTimestamps = {};
    try {
      let { TelemetryTimestamps } = ChromeUtils.importESModule(
        "resource://gre/modules/TelemetryTimestamps.sys.mjs"
      );
      // Supplies `blankWindowShown`
      appTimestamps = TelemetryTimestamps.get();
    } catch (ex) {}

    if (si.process) {
      for (let field of Object.keys(si)) {
        if (field == "process") {
          continue;
        }
        ret[field] = si[field] - si.process;
      }

      for (let p in appTimestamps) {
        if (!(p in ret) && appTimestamps[p]) {
          ret[p] = appTimestamps[p] - si.process;
        }
      }
    }

    // Remove all fields in `ret` that the pipeline doesn't know about:
    const knownFields = [
      "blankWindowShown",
      "firstPaint",
      "main",
      "sessionRestored",
      "totalTime",
    ];
    ret = Object.fromEntries(
      Object.entries(ret).filter(([key, _v]) => knownFields.includes(key))
    );

    if (Utils.isContentProcess) {
      return ret;
    }

    let activeTicks = this._sessionActiveTicks;
    if (isSubsession) {
      activeTicks = this._sessionActiveTicks - this._subsessionStartActiveTicks;
    }

    if (clearSubsession) {
      this._subsessionStartActiveTicks = this._sessionActiveTicks;
    }

    ret.activeTicks = activeTicks;

    return ret;
  },

  getHistograms: function getHistograms(clearSubsession) {
    const snapshot = Services.telemetry.getSnapshotForHistograms(
      "main",
      clearSubsession,
      !this._testing
    );
    if (
      lazy.NimbusFeatures.legacyTelemetry.getVariable("disableMainPingHgrams")
    ) {
      this._log.trace("getHistograms - Main ping histograms are disabled.");
      return {};
    }
    return snapshot;
  },

  getKeyedHistograms(clearSubsession) {
    const snapshot = Services.telemetry.getSnapshotForKeyedHistograms(
      "main",
      clearSubsession,
      !this._testing
    );
    if (
      lazy.NimbusFeatures.legacyTelemetry.getVariable("disableMainPingHgrams")
    ) {
      this._log.trace(
        "getKeyedHistograms - Main ping histograms are disabled."
      );
      return {};
    }
    return snapshot;
  },

  /**
   * Get a snapshot of the scalars and clear them.
   *
   * @param {subsession} If true, then we collect the data for a subsession.
   * @param {clearSubsession} If true, we  need to clear the subsession.
   * @param {keyed} Take a snapshot of keyed or non keyed scalars.
   * @return {object} The scalar data as a Javascript object, including the
   *         data from child processes, in the following format:
   *            {'content': { 'scalarName': ... }, 'gpu': { ... } }
   */
  getScalars(subsession, clearSubsession, keyed) {
    if (!subsession) {
      // We only support scalars for subsessions.
      this._log.trace("getScalars - We only support scalars in subsessions.");
      return {};
    }

    let scalarsSnapshot = keyed
      ? Services.telemetry.getSnapshotForKeyedScalars(
          "main",
          clearSubsession,
          !this._testing
        )
      : Services.telemetry.getSnapshotForScalars(
          "main",
          clearSubsession,
          !this._testing
        );

    if (
      lazy.NimbusFeatures.legacyTelemetry.getVariable("disableMainPingScalars")
    ) {
      this._log.trace("getScalars - Main ping scalars are disabled.");
      if (keyed) {
        // We don't need to preserve any keyed scalars.
        scalarsSnapshot = {};
      } else {
        let filteredSnapshot = {};
        const scalarsToKeep = [
          "browser.engagement.total_uri_count_normal_and_private_mode",
          "browser.engagement.active_ticks",
        ];
        for (let scalar of scalarsToKeep) {
          if ("parent" in scalarsSnapshot && scalar in scalarsSnapshot.parent) {
            if (!("parent" in filteredSnapshot)) {
              filteredSnapshot.parent = {};
            }
            filteredSnapshot.parent[scalar] = scalarsSnapshot.parent[scalar];
          }
        }
        scalarsSnapshot = filteredSnapshot;
      }
    }

    return scalarsSnapshot;
  },

  /**
   * Descriptive metadata
   *
   * @param  reason
   *         The reason for the telemetry ping, this will be included in the
   *         returned metadata,
   * @return The metadata as a JS object
   */
  getMetadata: function getMetadata(reason) {
    const sessionStartDate = Utils.toLocalTimeISOString(
      Utils.truncateToHours(this._sessionStartDate)
    );
    const subsessionStartDate = Utils.toLocalTimeISOString(
      Utils.truncateToHours(this._subsessionStartDate)
    );
    const monotonicNow = Policy.monotonicNow();

    let ret = {
      reason,
      revision: AppConstants.SOURCE_REVISION_URL,

      // Date.getTimezoneOffset() unintuitively returns negative values if we are ahead of
      // UTC and vice versa (e.g. -60 for UTC+1). We invert the sign here.
      timezoneOffset: -this._subsessionStartDate.getTimezoneOffset(),
      previousBuildId: this._previousBuildId,

      sessionId: this._sessionId,
      subsessionId: this._subsessionId,
      previousSessionId: this._previousSessionId,
      previousSubsessionId: this._previousSubsessionId,

      subsessionCounter: this._subsessionCounter,
      profileSubsessionCounter: this._profileSubsessionCounter,

      sessionStartDate,
      subsessionStartDate,

      // Compute the session and subsession length in seconds.
      // We use monotonic clocks as Date() is affected by jumping clocks (leading
      // to negative lengths and other issues).
      sessionLength: Math.floor(monotonicNow / 1000),
      subsessionLength: Math.floor(
        (monotonicNow - this._subsessionStartTimeMonotonic) / 1000
      ),
    };

    // TODO: Remove this when bug 1201837 lands.
    if (this._addons) {
      ret.addons = this._addons;
    }

    return ret;
  },

  /**
   * Get the current session's payload using the provided
   * simpleMeasurements and info, which are typically obtained by a call
   * to |this.getSimpleMeasurements| and |this.getMetadata|,
   * respectively.
   */
  assemblePayloadWithMeasurements(
    simpleMeasurements,
    info,
    reason,
    clearSubsession
  ) {
    const isSubsession = IS_UNIFIED_TELEMETRY && !this._isClassicReason(reason);
    clearSubsession = IS_UNIFIED_TELEMETRY && clearSubsession;
    this._log.trace(
      "assemblePayloadWithMeasurements - reason: " +
        reason +
        ", submitting subsession data: " +
        isSubsession
    );

    // This allows wrapping data retrieval calls in a try-catch block so that
    // failures don't break the rest of the ping assembly.
    const protect = (fn, defaultReturn = null) => {
      try {
        return fn();
      } catch (ex) {
        this._log.error(
          "assemblePayloadWithMeasurements - caught exception",
          ex
        );
        return defaultReturn;
      }
    };

    // Payload common to chrome and content processes.
    let payloadObj = {
      ver: PAYLOAD_VERSION,
      simpleMeasurements,
    };

    // Add extended set measurements common to chrome & content processes
    if (Services.telemetry.canRecordExtended) {
      payloadObj.log = [];
    }

    if (Utils.isContentProcess) {
      return payloadObj;
    }

    // Additional payload for chrome process.
    let measurements = {
      histograms: protect(() => this.getHistograms(clearSubsession), {}),
      keyedHistograms: protect(
        () => this.getKeyedHistograms(clearSubsession),
        {}
      ),
      scalars: protect(
        () => this.getScalars(isSubsession, clearSubsession),
        {}
      ),
      keyedScalars: protect(
        () => this.getScalars(isSubsession, clearSubsession, true),
        {}
      ),
    };

    let measurementsContainGPU = Object.keys(measurements).some(
      key => "gpu" in measurements[key]
    );

    let measurementsContainSocket = Object.keys(measurements).some(
      key => "socket" in measurements[key]
    );

    payloadObj.processes = {};
    let processTypes = ["parent", "content", "dynamic"];
    // Only include the GPU process if we've accumulated data for it.
    if (measurementsContainGPU) {
      processTypes.push("gpu");
    }
    if (measurementsContainSocket) {
      processTypes.push("socket");
    }

    // Collect per-process measurements.
    for (const processType of processTypes) {
      let processPayload = {};

      for (const key in measurements) {
        let payloadLoc = processPayload;
        // Parent histograms are added to the top-level payload object instead of the process payload.
        if (
          processType == "parent" &&
          (key == "histograms" || key == "keyedHistograms")
        ) {
          payloadLoc = payloadObj;
        }
        // The Dynamic process only collects scalars and keyed scalars.
        if (
          processType == "dynamic" &&
          key !== "scalars" &&
          key !== "keyedScalars"
        ) {
          continue;
        }

        // Process measurements can be empty, set a default value.
        payloadLoc[key] = measurements[key][processType] || {};
      }

      // Add process measurements to payload.
      payloadObj.processes[processType] = processPayload;
    }

    payloadObj.info = info;

    // Add extended set measurements for chrome process.
    if (Services.telemetry.canRecordExtended) {
      payloadObj.slowSQL = protect(() => Services.telemetry.slowSQL);
      payloadObj.fileIOReports = protect(
        () => Services.telemetry.fileIOReports
      );

      payloadObj.addonDetails = protect(() =>
        lazy.AddonManagerPrivate.getTelemetryDetails()
      );

      if (
        this._slowSQLStartup &&
        !!Object.keys(this._slowSQLStartup).length &&
        (Object.keys(this._slowSQLStartup.mainThread).length ||
          Object.keys(this._slowSQLStartup.otherThreads).length)
      ) {
        payloadObj.slowSQLStartup = this._slowSQLStartup;
      }
    }

    return payloadObj;
  },

  /**
   * Start a new subsession.
   */
  startNewSubsession() {
    this._subsessionStartDate = Policy.now();
    this._subsessionStartTimeMonotonic = Policy.monotonicNow();
    this._previousSubsessionId = this._subsessionId;
    this._subsessionId = Policy.generateSubsessionUUID();
    this._subsessionCounter++;
    this._profileSubsessionCounter++;
  },

  getSessionPayload: function getSessionPayload(reason, clearSubsession) {
    this._log.trace(
      "getSessionPayload - reason: " +
        reason +
        ", clearSubsession: " +
        clearSubsession
    );

    let payload;
    try {
      const isMobile = AppConstants.platform == "android";
      const isSubsession = isMobile ? false : !this._isClassicReason(reason);

      // The order of the next two msSinceProcessStart* calls is somewhat
      // important. In theory, `session_time_including_suspend` is supposed to
      // ALWAYS be lower or equal than `session_time_excluding_suspend` (because
      // the former is a temporal superset of the latter). When a device has not
      // been suspended since boot, we want the previous property to hold,
      // regardless of the delay during or between the two
      // `msSinceProcessStart*` calls.
      Glean.browserEngagement.sessionTimeExcludingSuspend.set(
        Services.telemetry.msSinceProcessStartExcludingSuspend()
      );
      Glean.browserEngagement.sessionTimeIncludingSuspend.set(
        Services.telemetry.msSinceProcessStartIncludingSuspend()
      );

      if (isMobile) {
        clearSubsession = false;
      }

      let measurements = this.getSimpleMeasurements(
        reason == REASON_SAVED_SESSION,
        isSubsession,
        clearSubsession
      );
      let info = !Utils.isContentProcess ? this.getMetadata(reason) : null;
      payload = this.assemblePayloadWithMeasurements(
        measurements,
        info,
        reason,
        clearSubsession
      );
    } finally {
      if (!Utils.isContentProcess && clearSubsession) {
        this.startNewSubsession();
        // Persist session data to disk (don't wait until it completes).
        let sessionData = this._getSessionDataObject();
        lazy.TelemetryStorage.saveSessionData(sessionData);

        // Notify that there was a subsession split in the parent process. This is an
        // internal topic and is only meant for internal Telemetry usage.
        Services.obs.notifyObservers(
          null,
          "internal-telemetry-after-subsession-split"
        );
      }
    }

    return payload;
  },

  /**
   * Send data to the server. Record success/send-time in histograms
   */
  send: async function send(reason) {
    this._log.trace("send - Reason " + reason);
    // populate histograms one last time
    await Services.telemetry.gatherMemory();

    const isSubsession = !this._isClassicReason(reason);
    let payload = this.getSessionPayload(reason, isSubsession);
    let options = {
      addClientId: true,
      addEnvironment: true,
    };
    return lazy.TelemetryController.submitExternalPing(
      getPingType(payload),
      payload,
      options
    );
  },

  /**
   * Attaches the needed observers during Telemetry early init, in the
   * chrome process.
   */
  attachEarlyObservers() {
    if (!this._earlyObserversRegistered) {
      this.addObserver("sessionstore-windows-restored");
      if (AppConstants.platform === "android") {
        this.addObserver("application-background");
      }
      this.addObserver("xul-window-visible");

      // Attach the active-ticks related observers.
      this.addObserver("user-interaction-active");
      this.addObserver("user-interaction-inactive");
      this.addObserver("user-interaction-active-non-synthesized");
      this.addObserver("user-interaction-inactive-non-synthesized");
      this._earlyObserversRegistered = true;
    }
  },

  /**
   * Lightweight init function, called as soon as Firefox starts.
   */
  earlyInit(testing) {
    this._log.trace("earlyInit");

    this._initStarted = true;
    this._testing = testing;

    if (this._initialized && !testing) {
      this._log.error("earlyInit - already initialized");
      return;
    }

    if (!Services.telemetry.canRecordBase && !testing) {
      this._log.config(
        "earlyInit - Telemetry recording is disabled, skipping Chrome process setup."
      );
      return;
    }

    // Generate a unique id once per session so the server can cope with duplicate
    // submissions, orphaning and other oddities. The id is shared across subsessions.
    this._sessionId = Policy.generateSessionUUID();
    Glean.legacyTelemetry.sessionId.set(this._sessionId);
    this.startNewSubsession();
    // startNewSubsession sets |_subsessionStartDate| to the current date/time. Use
    // the very same value for |_sessionStartDate|.
    this._sessionStartDate = this._subsessionStartDate;
    Glean.legacyTelemetry.sessionStartDate.set(
      this._sessionStartDate.getTime() * 1000
    );

    annotateCrashReport(this._sessionId);

    // Record old value and update build ID preference if this is the first
    // run with a new build ID.
    let previousBuildId = Services.prefs.getStringPref(
      TelemetryUtils.Preferences.PreviousBuildID,
      null
    );
    let thisBuildID = Services.appinfo.appBuildID;
    // If there is no previousBuildId preference, we send null to the server.
    if (previousBuildId != thisBuildID) {
      this._previousBuildId = previousBuildId;
      Services.prefs.setStringPref(
        TelemetryUtils.Preferences.PreviousBuildID,
        thisBuildID
      );
    }

    this.attachEarlyObservers();
  },

  /**
   * Does the "heavy" Telemetry initialization later on, so we
   * don't impact startup performance.
   *
   * @return {Promise} Resolved when the initialization completes.
   */
  delayedInit() {
    this._log.trace("delayedInit");

    this._delayedInitTask = (async () => {
      try {
        this._initialized = true;

        await this._loadSessionData();
        // Update the session data to keep track of new subsessions created before
        // the initialization.
        await lazy.TelemetryStorage.saveSessionData(
          this._getSessionDataObject()
        );

        if (!this._delayedObserversRegistered) {
          this.addObserver("idle-daily");
          this._delayedObserversRegistered = true;
        }
        await Services.telemetry.gatherMemory();

        Services.telemetry.asyncFetchTelemetryData(function () {});

        if (IS_UNIFIED_TELEMETRY) {
          // Check for a previously written aborted session ping.
          await lazy.TelemetryController.checkAbortedSessionPing();

          // Write the first aborted-session ping as early as possible. Just do that
          // if we are not testing, since calling Telemetry.reset() will make a previous
          // aborted ping a pending ping.
          if (!this._testing) {
            await this._saveAbortedSessionPing();
          }

          // The last change date for the environment, used to throttle environment changes.
          this._lastEnvironmentChangeDate = Policy.monotonicNow();
          lazy.TelemetryEnvironment.registerChangeListener(
            ENVIRONMENT_CHANGE_LISTENER,
            (reason, data) => this._onEnvironmentChange(reason, data)
          );

          // Start the scheduler.
          // We skip this if unified telemetry is off, so we don't
          // trigger the new unified ping types.
          lazy.TelemetryScheduler.init();
        }

        this._delayedInitTask = null;
      } catch (e) {
        this._delayedInitTask = null;
        throw e;
      }
    })();

    return this._delayedInitTask;
  },

  /**
   * On Desktop: Save the "shutdown" ping to disk.
   * On Android: Save the "saved-session" ping to disk.
   * This needs to be called after TelemetrySend shuts down otherwise pings
   * would be sent instead of getting persisted to disk.
   */
  saveShutdownPings() {
    this._log.trace("saveShutdownPings");

    // We append the promises to this list and wait
    // on all pings to be saved after kicking off their collection.
    let p = [];

    if (IS_UNIFIED_TELEMETRY) {
      let shutdownPayload = this.getSessionPayload(REASON_SHUTDOWN, false);

      // Only send the shutdown ping using the pingsender from the second
      // browsing session on, to mitigate issues with "bot" profiles (see bug 1354482).
      const sendOnThisSession =
        Services.prefs.getBoolPref(
          Utils.Preferences.ShutdownPingSenderFirstSession,
          false
        ) || !lazy.TelemetryReportingPolicy.isFirstRun();
      let sendWithPingsender =
        Services.prefs.getBoolPref(
          TelemetryUtils.Preferences.ShutdownPingSender,
          false
        ) && sendOnThisSession;

      let options = {
        addClientId: true,
        addEnvironment: true,
        usePingSender: sendWithPingsender,
      };
      p.push(
        lazy.TelemetryController.submitExternalPing(
          getPingType(shutdownPayload),
          shutdownPayload,
          options
        ).catch(e =>
          this._log.error(
            "saveShutdownPings - failed to submit shutdown ping",
            e
          )
        )
      );

      // Send a duplicate of first-shutdown pings as a new ping type, in order to properly
      // evaluate first session profiles (see bug 1390095).
      const sendFirstShutdownPing =
        Services.prefs.getBoolPref(
          Utils.Preferences.ShutdownPingSender,
          false
        ) &&
        Services.prefs.getBoolPref(
          Utils.Preferences.FirstShutdownPingEnabled,
          false
        ) &&
        lazy.TelemetryReportingPolicy.isFirstRun();

      if (sendFirstShutdownPing) {
        options = {
          addClientId: true,
          addEnvironment: true,
          usePingSender: true,
        };
        p.push(
          lazy.TelemetryController.submitExternalPing(
            "first-shutdown",
            shutdownPayload,
            options
          ).catch(e =>
            this._log.error(
              "saveShutdownPings - failed to submit first shutdown ping",
              e
            )
          )
        );
      }
    }

    if (
      AppConstants.platform == "android" &&
      Services.telemetry.canRecordExtended
    ) {
      let payload = this.getSessionPayload(REASON_SAVED_SESSION, false);

      let options = {
        addClientId: true,
        addEnvironment: true,
      };
      p.push(
        lazy.TelemetryController.submitExternalPing(
          getPingType(payload),
          payload,
          options
        ).catch(e =>
          this._log.error(
            "saveShutdownPings - failed to submit saved-session ping",
            e
          )
        )
      );
    }

    // Wait on pings to be saved.
    return Promise.all(p);
  },

  testSavePendingPing() {
    let payload = this.getSessionPayload(REASON_SAVED_SESSION, false);
    let options = {
      addClientId: true,
      addEnvironment: true,
      overwrite: true,
    };
    return lazy.TelemetryController.addPendingPing(
      getPingType(payload),
      payload,
      options
    );
  },

  /**
   * Do some shutdown work that is common to all process types.
   */
  uninstall() {
    for (let topic of this._observedTopics) {
      try {
        // Tests may flip Telemetry.canRecordExtended on and off. It can be the case
        // that the observer TOPIC_CYCLE_COLLECTOR_BEGIN was not added.
        this.removeObserver(topic);
      } catch (e) {
        this._log.warn("uninstall - Failed to remove " + topic, e);
      }
    }
    this._earlyObserversRegistered = false;
    this._delayedObserversRegistered = false;
  },

  getPayload: function getPayload(reason, clearSubsession) {
    this._log.trace("getPayload - clearSubsession: " + clearSubsession);
    reason = reason || REASON_GATHER_PAYLOAD;
    // This function returns the current Telemetry payload to the caller.
    // We only gather startup info once.
    if (!Object.keys(this._slowSQLStartup).length) {
      this._slowSQLStartup = Services.telemetry.slowSQL;
    }
    Services.telemetry.gatherMemory();
    return this.getSessionPayload(reason, clearSubsession);
  },

  gatherStartup: function gatherStartup() {
    this._log.trace("gatherStartup");
    let counters = processInfo.getCounters();
    if (counters) {
      [
        this._startupIO.startupSessionRestoreReadBytes,
        this._startupIO.startupSessionRestoreWriteBytes,
      ] = counters;
      Glean.startupIo.read.sessionRestore.set(counters[0]);
      Glean.startupIo.write.sessionRestore.set(counters[1]);
    }
    this._slowSQLStartup = Services.telemetry.slowSQL;
  },

  setAddOns: function setAddOns(aAddOns) {
    this._addons = aAddOns;
  },

  testPing: function testPing() {
    return this.send(REASON_TEST_PING);
  },

  /**
   * Tracks the number of "ticks" the user was active in.
   */
  _onActiveTick(aUserActive) {
    const wasActive = this._isUserActive;
    this._isUserActive = aUserActive;

    // Don't count the first active tick after we get out of
    // inactivity, because it is just the start of this active tick.
    if (aUserActive && wasActive) {
      this._sessionActiveTicks++;
      Glean.browserEngagement.activeTicks.add(1);
      this._consecutiveActiveTicks++;
    } else if (wasActive && !aUserActive) {
      // The run of active ticks just ended: record its length (if any) and
      // start timing the inactive period that is beginning now.
      if (this._consecutiveActiveTicks > 0) {
        Glean.browserEngagement.consecutiveActiveTicks.active_ticks.accumulateSingleSample(
          this._consecutiveActiveTicks
        );
        this._consecutiveActiveTicks = 0;
      }
      this._inactiveTimerId =
        Glean.browserEngagement.inactivePeriodDuration.active_ticks.start();
    } else if (!wasActive && aUserActive && this._inactiveTimerId !== null) {
      // Activity resumed: record the duration of the inactive period.
      Glean.browserEngagement.inactivePeriodDuration.active_ticks.stopAndAccumulate(
        this._inactiveTimerId
      );
      this._inactiveTimerId = null;
    }
  },

  /**
   * Like _onActiveTick, but only counts ticks driven by non-synthesized events.
   * Recorded side-by-side with activeTicks for data continuity while the
   * correction is evaluated.
   */
  _onActiveTickNonSynthesized(aUserActive) {
    const wasActive = this._isUserActiveNonSynthesized;
    this._isUserActiveNonSynthesized = aUserActive;

    if (aUserActive && wasActive) {
      Glean.browserEngagement.activeTicksNonSynthesized.add(1);
      this._consecutiveActiveTicksNonSynthesized++;
    } else if (wasActive && !aUserActive) {
      if (this._consecutiveActiveTicksNonSynthesized > 0) {
        Glean.browserEngagement.consecutiveActiveTicks.active_ticks_non_synthesized.accumulateSingleSample(
          this._consecutiveActiveTicksNonSynthesized
        );
        this._consecutiveActiveTicksNonSynthesized = 0;
      }
      this._inactiveTimerIdNonSynthesized =
        Glean.browserEngagement.inactivePeriodDuration.active_ticks_non_synthesized.start();
    } else if (
      !wasActive &&
      aUserActive &&
      this._inactiveTimerIdNonSynthesized !== null
    ) {
      Glean.browserEngagement.inactivePeriodDuration.active_ticks_non_synthesized.stopAndAccumulate(
        this._inactiveTimerIdNonSynthesized
      );
      this._inactiveTimerIdNonSynthesized = null;
    }
  },

  /**
   * This observer drives telemetry.
   */
  observe(aSubject, aTopic) {
    this._log.trace("observe - " + aTopic + " notified.");

    switch (aTopic) {
      case "xul-window-visible":
        this.removeObserver("xul-window-visible");
        var counters = processInfo.getCounters();
        if (counters) {
          [
            this._startupIO.startupWindowVisibleReadBytes,
            this._startupIO.startupWindowVisibleWriteBytes,
          ] = counters;
          Glean.startupIo.read.windowVisible.set(counters[0]);
          Glean.startupIo.write.windowVisible.set(counters[1]);
        }
        break;
      case "sessionstore-windows-restored": {
        this.removeObserver("sessionstore-windows-restored");
        this.gatherStartup();
        break;
      }
      case "idle-daily":
        // Enqueue to main-thread, otherwise components may be inited by the
        // idle-daily category and miss the notification.
        Services.tm.dispatchToMainThread(function () {});
        break;

      case "application-background": {
        if (AppConstants.platform !== "android") {
          break;
        }
        // On Android, we can get killed without warning once we are in the background,
        // but we may also submit data and/or come back into the foreground without getting
        // killed. To deal with this, we save the current session data to file when we are
        // put into the background. This handles the following post-backgrounding scenarios:
        // 1) We are killed immediately. In this case the current session data (which we
        //    save to a file) will be loaded and submitted on a future run.
        // 2) We submit the data while in the background, and then are killed. In this case
        //    the file that we saved will be deleted by the usual process in
        //    finishPingRequest after it is submitted.
        // 3) We submit the data, and then come back into the foreground. Same as case (2).
        // 4) We do not submit the data, but come back into the foreground. In this case
        //    we have the option of either deleting the file that we saved (since we will either
        //    send the live data while in the foreground, or create the file again on the next
        //    backgrounding), or not (in which case we will delete it on submit, or overwrite
        //    it on the next backgrounding). Not deleting it is faster, so that's what we do.
        let payload = this.getSessionPayload(REASON_SAVED_SESSION, false);
        let options = {
          addClientId: true,
          addEnvironment: true,
          overwrite: true,
        };
        lazy.TelemetryController.addPendingPing(
          getPingType(payload),
          payload,
          options
        );
        break;
      }
      case "user-interaction-active":
        this._onActiveTick(true);
        break;
      case "user-interaction-inactive":
        this._onActiveTick(false);
        break;
      case "user-interaction-active-non-synthesized":
        this._onActiveTickNonSynthesized(true);
        break;
      case "user-interaction-inactive-non-synthesized":
        this._onActiveTickNonSynthesized(false);
        break;
    }
    return undefined;
  },

  /**
   * This tells TelemetrySession to uninitialize and save any pending pings.
   */
  shutdownChromeProcess() {
    this._log.trace("shutdownChromeProcess");

    let cleanup = () => {
      if (IS_UNIFIED_TELEMETRY) {
        lazy.TelemetryEnvironment.unregisterChangeListener(
          ENVIRONMENT_CHANGE_LISTENER
        );
        lazy.TelemetryScheduler.shutdown();
      }
      this.uninstall();

      let reset = () => {
        this._initStarted = false;
        this._initialized = false;
      };

      return (async () => {
        await this.saveShutdownPings();

        if (IS_UNIFIED_TELEMETRY) {
          await lazy.TelemetryController.removeAbortedSessionPing();
        }

        reset();
      })();
    };

    // We can be in one the following states here:
    // 1) delayedInit was never called
    // or it was called and
    //   2) _delayedInitTask is running now.
    //   3) _delayedInitTask finished running already.

    // This handles 1).
    if (!this._initStarted) {
      return Promise.resolve();
    }

    // This handles 3).
    if (!this._delayedInitTask) {
      // We already ran the delayed initialization.
      return cleanup();
    }

    // This handles 2).
    return this._delayedInitTask.then(cleanup);
  },

  /**
   * Gather and send a daily ping.
   *
   * @return {Promise} Resolved when the ping is sent.
   */
  _sendDailyPing() {
    this._log.trace("_sendDailyPing");
    let payload = this.getSessionPayload(REASON_DAILY, true);

    let options = {
      addClientId: true,
      addEnvironment: true,
    };

    let promise = lazy.TelemetryController.submitExternalPing(
      getPingType(payload),
      payload,
      options
    );

    // Also save the payload as an aborted session. If we delay this, aborted-session can
    // lag behind for the profileSubsessionCounter and other state, complicating analysis.
    if (IS_UNIFIED_TELEMETRY) {
      this._saveAbortedSessionPing(payload).catch(e =>
        this._log.error(
          "_sendDailyPing - Failed to save the aborted session ping",
          e
        )
      );
    }

    return promise;
  },

  /**
   * Loads session data from the session data file.
   *
   * @return {Promise<object>} A promise which is resolved with an object when
   *                            loading has completed, with null otherwise.
   */
  async _loadSessionData() {
    let data = await lazy.TelemetryStorage.loadSessionData();

    if (!data) {
      return null;
    }

    if (
      !("profileSubsessionCounter" in data) ||
      !(typeof data.profileSubsessionCounter == "number") ||
      !("subsessionId" in data) ||
      !("sessionId" in data)
    ) {
      this._log.error("_loadSessionData - session data is invalid");
      return null;
    }

    this._previousSessionId = data.sessionId;
    this._previousSubsessionId = data.subsessionId;
    // Add |_subsessionCounter| to the |_profileSubsessionCounter| to account for
    // new subsession while loading still takes place. This will always be exactly
    // 1 - the current subsessions.
    this._profileSubsessionCounter =
      data.profileSubsessionCounter + this._subsessionCounter;
    // If we don't have this flag in the state file, it means that this is an old profile.
    // We don't want to send the "new-profile" ping on new profile, so se this to true.
    this._newProfilePingSent =
      "newProfilePingSent" in data ? data.newProfilePingSent : true;
    return data;
  },

  /**
   * Get the session data object to serialise to disk.
   */
  _getSessionDataObject() {
    return {
      sessionId: this._sessionId,
      subsessionId: this._subsessionId,
      profileSubsessionCounter: this._profileSubsessionCounter,
      newProfilePingSent: this._newProfilePingSent,
    };
  },

  _onEnvironmentChange(reason, oldEnvironment) {
    this._log.trace("_onEnvironmentChange", reason);

    let now = Policy.monotonicNow();
    let timeDelta = now - this._lastEnvironmentChangeDate;
    if (timeDelta <= MIN_SUBSESSION_LENGTH_MS) {
      this._log.trace(
        `_onEnvironmentChange - throttling; last change was ${Math.round(
          timeDelta / 1000
        )}s ago.`
      );
      return;
    }

    this._lastEnvironmentChangeDate = now;
    let payload = this.getSessionPayload(REASON_ENVIRONMENT_CHANGE, true);
    lazy.TelemetryScheduler.rescheduleDailyPing(payload);

    let options = {
      addClientId: true,
      addEnvironment: true,
      overrideEnvironment: oldEnvironment,
    };
    lazy.TelemetryController.submitExternalPing(
      getPingType(payload),
      payload,
      options
    );
  },

  _isClassicReason(reason) {
    const classicReasons = [
      REASON_SAVED_SESSION,
      REASON_GATHER_PAYLOAD,
      REASON_TEST_PING,
    ];
    return classicReasons.includes(reason);
  },

  /**
   * Get an object describing the current state of this module for AsyncShutdown diagnostics.
   */
  _getState() {
    return {
      initialized: this._initialized,
      initStarted: this._initStarted,
      haveDelayedInitTask: !!this._delayedInitTask,
    };
  },

  /**
   * Saves the aborted session ping to disk.
   *
   * @param {object} [aProvidedPayload=null] A payload object to be used as an aborted
   *                 session ping. The reason of this payload is changed to aborted-session.
   *                 If not provided, a new payload is gathered.
   */
  _saveAbortedSessionPing(aProvidedPayload = null) {
    this._log.trace("_saveAbortedSessionPing");

    let payload = null;
    if (aProvidedPayload) {
      payload = Cu.cloneInto(aProvidedPayload, {});
      // Overwrite the original reason.
      payload.info.reason = REASON_ABORTED_SESSION;
    } else {
      payload = this.getSessionPayload(REASON_ABORTED_SESSION, false);
    }

    return lazy.TelemetryController.saveAbortedSessionPing(payload);
  },

  async markNewProfilePingSent() {
    this._log.trace("markNewProfilePingSent");
    this._newProfilePingSent = true;
    return lazy.TelemetryStorage.saveSessionData(this._getSessionDataObject());
  },
};
