// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_UPGRADE_DETECTOR_UPGRADE_DETECTOR_H_
#define CHROME_BROWSER_UPGRADE_DETECTOR_UPGRADE_DETECTOR_H_

#include <optional>
#include <string>

#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/sequence_checker.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "build/build_config.h"
#include "chrome/browser/upgrade_detector/upgrade_observer.h"
#include "components/prefs/pref_change_registrar.h"

class PrefRegistrySimple;
class UpgradeObserver;
namespace base {
class Clock;
class TickClock;
}

///////////////////////////////////////////////////////////////////////////////
// UpgradeDetector
//
// This class is a singleton class that monitors when an upgrade happens in the
// background. We basically ask Omaha what it thinks the latest version is and
// if our version is lower we send out a notification upon:
//   a) Detecting an upgrade and...
//   b) When we think the user should be notified about the upgrade.
// The latter happens much later, since we don't want to be too annoying.
// This class is not thread safe -- all access must take place on the UI thread.
//
class UpgradeDetector {
 public:
  // The Homeland Security Upgrade Advisory System.
  // These values are persisted to logs. Entries should not be renumbered and
  // numeric values should never be reused.
  enum UpgradeNotificationAnnoyanceLevel {
    UPGRADE_ANNOYANCE_NONE = 0,      // What? Me worry?
    UPGRADE_ANNOYANCE_LOW = 1,       // Green.
    UPGRADE_ANNOYANCE_ELEVATED = 2,  // Yellow.
    UPGRADE_ANNOYANCE_HIGH = 3,      // Red.
    // UPGRADE_ANNOYANCE_SEVERE = 4,  // Removed in 2018-03 for lack of use.
    UPGRADE_ANNOYANCE_CRITICAL = 5,  // Red exclamation mark.
    UPGRADE_ANNOYANCE_VERY_LOW = 6,  // Green early warning for canary and dev.
    UPGRADE_ANNOYANCE_GRACE = 7,     // Red last warning before deadline.
    UPGRADE_ANNOYANCE_MAX_VALUE = UPGRADE_ANNOYANCE_GRACE
  };

  struct RelaunchWindow {
    constexpr RelaunchWindow(int start_hour,
                             int start_minute,
                             base::TimeDelta duration)
        : hour(start_hour), minute(start_minute), duration(duration) {}

    bool IsValid() const {
      return hour >= 0 && hour <= 23 && minute >= 0 && minute <= 59 &&
             duration >= base::Minutes(1) && duration != base::TimeDelta::Max();
    }

    int hour;
    int minute;
    base::TimeDelta duration;
  };

  // Returns the singleton implementation instance.
  static UpgradeDetector* GetInstance();

  UpgradeDetector(const UpgradeDetector&) = delete;
  UpgradeDetector& operator=(const UpgradeDetector&) = delete;

  virtual ~UpgradeDetector();

  // Returns the default delta from upgrade detection until high annoyance is
  // reached.
  static base::TimeDelta GetDefaultHighAnnoyanceThreshold();

  // Returns the default delta from upgrade detection until elevated annoyance
  // is reached.
  static base::TimeDelta GetDefaultElevatedAnnoyanceThreshold();

  static void RegisterPrefs(PrefRegistrySimple* registry);

  virtual void Init();
  virtual void Shutdown();

  // Returns the time at which an available upgrade was detected.
  base::Time upgrade_detected_time() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return upgrade_detected_time_;
  }

  // Whether the user should be notified about an upgrade.
  bool notify_upgrade() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return notify_upgrade_;
  }

  // Whether the upgrade recommendation is due to Chrome being outdated.
  bool is_outdated_install() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return upgrade_available_ == UPGRADE_NEEDED_OUTDATED_INSTALL;
  }

  // Whether the upgrade recommendation is due to Chrome being outdated AND
  // auto-update is turned off.
  bool is_outdated_install_no_au() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return upgrade_available_ == UPGRADE_NEEDED_OUTDATED_INSTALL_NO_AU;
  }

  // Returns true if the detector has found that a newer version of Chrome is
  // installed and a relaunch would complete the update.
  bool is_upgrade_available() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return upgrade_available_ == UPGRADE_AVAILABLE_REGULAR ||
           upgrade_available_ == UPGRADE_AVAILABLE_CRITICAL;
  }

  // Notify this object that the user has acknowledged the critical update so we
  // don't need to complain about it for now.
  void acknowledge_critical_update() {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    critical_update_acknowledged_ = true;
  }

  // Whether the user has acknowledged the critical update.
  bool critical_update_acknowledged() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return critical_update_acknowledged_;
  }

#if BUILDFLAG(IS_CHROMEOS)
  bool is_factory_reset_required() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return is_factory_reset_required_;
  }

  bool is_rollback() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return is_rollback_;
  }
#endif  // BUILDFLAG(IS_CHROMEOS)

  UpgradeNotificationAnnoyanceLevel upgrade_notification_stage() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return upgrade_notification_stage_;
  }

  // Returns the time at which `level` annoyance level will be (or was) reached,
  // or a null time object if an upgrade has not yet been detected.
  virtual base::Time GetAnnoyanceLevelDeadline(
      UpgradeNotificationAnnoyanceLevel level) = 0;

  // Overrides the "high" annoyance deadline, setting it to |deadline|. On
  // Chrome OS, this also sets the "elevated" annoyance deadline to the time at
  // which the available update was detected. This has no effect on desktop
  // Chrome browsers.
  virtual void OverrideHighAnnoyanceDeadline(base::Time deadine) {}

  // Resets the overridden deadlines and recalculates them according to the
  // thresholds from the Local State. This has no effect on desktop Chrome
  // browsers.
  virtual void ResetOverriddenDeadline() {}

  // Overrides the relaunch notification style to required if |override|; else
  // resets the override so that the policy settings take effect.
  void OverrideRelaunchNotificationToRequired(bool overridden);

  void AddObserver(UpgradeObserver* observer);

  void RemoveObserver(UpgradeObserver* observer);

  // Notifies that the current install is outdated. No details are expected.
  void NotifyOutdatedInstall();

  // Notifies that the current install is outdated and auto-update (AU) is
  // disabled. No details are expected.
  void NotifyOutdatedInstallNoAutoUpdate();

  void set_upgrade_notification_stage_for_testing(
      UpgradeNotificationAnnoyanceLevel stage) {
    set_upgrade_notification_stage(stage);
  }

  void NotifyUpgradeForTesting();

 protected:
  enum UpgradeAvailable {
    // If no update is available and current install is recent enough.
    UPGRADE_AVAILABLE_NONE,
    // If a regular update is available.
    UPGRADE_AVAILABLE_REGULAR,
    // If a critical update to Chrome has been installed, such as a zero-day
    // fix.
    UPGRADE_AVAILABLE_CRITICAL,
    // If no update to Chrome has been installed for more than the recommended
    // time.
    UPGRADE_NEEDED_OUTDATED_INSTALL,
    // If no update to Chrome has been installed for more than the recommended
    // time AND auto-update is turned off.
    UPGRADE_NEEDED_OUTDATED_INSTALL_NO_AU,
  };

  UpgradeDetector(const base::Clock* clock, const base::TickClock* tick_clock);

  // Starts observing changes to Local State preference `pref`.
  void MonitorPrefChanges(const std::string& pref);

  // Returns the notification period specified via the
  // RelaunchNotificationPeriod policy setting, or a zero delta if unset or out
  // of range.
  static base::TimeDelta GetRelaunchNotificationPeriod();
  static bool IsRelaunchNotificationPolicyEnabled();

  // Returns the adjusted deadline to fall within `window`. If the
  // `deadline` has already passed the window for the day, it is prolonged for
  // the next day within the window. If the `deadline` already falls within the
  // window, no change is made.
  static base::Time AdjustDeadline(base::Time deadline,
                                   const RelaunchWindow& window);

  // Returns the relaunch window specified via the RelaunchWindow policy
  // setting, or nullopt if unset or set incorrectly.
  static std::optional<RelaunchWindow> GetRelaunchWindowPolicyValue();

  // Returns the default relaunch window within which the relaunch should take
  // place. It is 2am to 4am from Chrome OS and the whole day for others.
  static RelaunchWindow GetDefaultRelaunchWindow();

  // Returns the delta between "grace" and "high" annoyance levels using
  // `elevated_to_high_delta` which is the delta between "elevated" and "high"
  // annoyance levels.
  static base::TimeDelta GetGracePeriod(base::TimeDelta elevated_to_high_delta);

  // Returns the network time, falling back to system time if unavailable.
  // Returns true if it's network time, or false if it's not.
  bool GetNetworkTimeWithFallback(base::Time& network_time);

  // Returns true if `last_served_date_` is known and older than the number
  // of days specified by the RelaunchFastIfOutdated policy.
  bool ShouldRelaunchFast();

  // Returns true if the last served date should be fetched on update, for
  // the RelaunchOutdatedInstall policy.
  bool ShouldFetchLastServedDate() const;

  // Fetches the last served date via GetLastServedDate(), and updates
  // `last_served_date_`.
  void FetchLastServedDate();

  const base::Clock* clock() {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return clock_;
  }

  const base::TickClock* tick_clock() {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return tick_clock_;
  }

  // Notifies that update is recommended and triggers different actions based
  // on the update availability.
  void NotifyUpgrade();

  // Notifies that update is recommended.
  void NotifyUpgradeRecommended();

  // Notifies that a critical update has been installed. No details are
  // expected.
  void NotifyCriticalUpgradeInstalled();

  // Notifies that an update is downloaded but deferred. Set `use_notification`
  // to true to enable system tray notification.
  void NotifyUpdateDeferred(bool use_notification);

  // The function that sends out a notification that lets the rest of the UI
  // know we should notify the user that a new update is available to download
  // over cellular connection.
  void NotifyUpdateOverCellularAvailable();

  // Notifies that the user's one time permission on update over cellular
  // connection has been granted.
  void NotifyUpdateOverCellularOneTimePermissionGranted();

  // Notifies about a request to override the relaunch notification style to
  // required or reset the overridden style.
  void NotifyRelaunchOverriddenToRequired(bool overridden);

  // Triggers a critical update, which starts a timer that checks the machine
  // idle state. Protected and virtual so that it could be overridden by tests.
  virtual void TriggerCriticalUpdate();

  UpgradeAvailable upgrade_available() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return upgrade_available_;
  }
  void set_upgrade_available(UpgradeAvailable available) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    upgrade_available_ = available;
  }

  void set_upgrade_detected_time(base::Time upgrade_detected_time) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    upgrade_detected_time_ = upgrade_detected_time;
  }

  void set_best_effort_experiment_updates_available(bool available) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    best_effort_experiment_updates_available_ = available;
  }

  bool critical_experiment_updates_available() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    return critical_experiment_updates_available_;
  }
  void set_critical_experiment_updates_available(bool available) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    critical_experiment_updates_available_ = available;
  }

  void set_critical_update_acknowledged(bool acknowledged) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    critical_update_acknowledged_ = acknowledged;
  }

  void set_upgrade_notification_stage(UpgradeNotificationAnnoyanceLevel stage) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    upgrade_notification_stage_ = stage;
  }

#if BUILDFLAG(IS_CHROMEOS)
  void set_is_factory_reset_required(bool is_factory_reset_required) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    is_factory_reset_required_ = is_factory_reset_required;
  }

  void set_is_rollback(bool is_rollback) {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
    is_rollback_ = is_rollback;
  }
#endif  // BUILDFLAG(IS_CHROMEOS)

 private:
  FRIEND_TEST_ALL_PREFIXES(AppMenuModelTest, Basics);
  FRIEND_TEST_ALL_PREFIXES(RelaunchNotificationControllerUiTest,
                           ReactivateAfterDeadline);
  FRIEND_TEST_ALL_PREFIXES(SystemTrayClientTest, UpdateTrayIcon);
  friend class RelaunchNotificationControllerUiTest;
  friend class UpgradeMetricsProviderTest;

  // Called on the UI thread after one or more monitored prefs or
  // `last_served_date_` have changed. If an update has been detected,
  // subclasses may need to recompute the schedule for advancing through the
  // annoyance levels.
  virtual void RecomputeSchedule() {}

  // Initiates an Idle check. Tells us whether Chrome has received any
  // input events since the specified time.
  void CheckIdle();

  // Handles a change to the relaunch notification related Local State
  // preferences. Posts a task to call OnThresholdPrefChanged() if it isn't
  // already posted and pending for execution.
  void OnRelaunchPrefChanged();

  // Handles the result of GetLastServedDate().
  void OnGotLastServedDate(std::optional<base::Time> last_served_date);

  // A provider of Time to the detector.
  const raw_ptr<const base::Clock> clock_;

  // A provider of TimeTicks to the detectors' timers.
  const raw_ptr<const base::TickClock> tick_clock_;

  // Observes changes to the browser.relaunch_notification_period Local State
  // preference.
  PrefChangeRegistrar pref_change_registrar_;

  // Whether any software updates are available (experiment updates are tracked
  // separately via additional member variables below).
  UpgradeAvailable upgrade_available_;

  // The time at which an available upgrade was detected.
  base::Time upgrade_detected_time_;

  // Whether "best effort" experiment updates are available.
  bool best_effort_experiment_updates_available_;

  // Whether "critical" experiment updates are available.
  bool critical_experiment_updates_available_;

  // Whether the user has acknowledged the critical update.
  bool critical_update_acknowledged_;

  // Whether a task posted on any relaunch preference change is still pending
  // for execution.
  bool pref_change_task_pending_ = false;

#if BUILDFLAG(IS_CHROMEOS)
  // Whether a factory reset is needed to complete an update.
  bool is_factory_reset_required_ = false;

  // Whether the update is actually an admin-initiated rollback of the device
  // to an earlier version of Chrome OS, which results in the device being
  // wiped when it's rebooted.
  bool is_rollback_ = false;
#endif  // BUILDFLAG(IS_CHROMEOS)

  // A timer to check to see if we've been idle for long enough to show the
  // critical warning. Should only be set if |upgrade_available_| is
  // UPGRADE_AVAILABLE_CRITICAL.
  base::RepeatingTimer idle_check_timer_;

  // The stage at which the annoyance level for upgrade notifications is at.
  UpgradeNotificationAnnoyanceLevel upgrade_notification_stage_;

  // Whether we have waited long enough after detecting an upgrade (to see
  // is we should start nagging about upgrading).
  bool notify_upgrade_;

  bool fetched_last_served_date_ = false;
  std::optional<base::Time> last_served_date_;

  SEQUENCE_CHECKER(sequence_checker_);

  base::ObserverList<UpgradeObserver>::Unchecked observer_list_;

  base::WeakPtrFactory<UpgradeDetector> weak_factory_{this};
};

#endif  // CHROME_BROWSER_UPGRADE_DETECTOR_UPGRADE_DETECTOR_H_