//
// Copyright (C) 2012 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.
//

#ifndef UPDATE_ENGINE_UPDATE_ATTEMPTER_H_
#define UPDATE_ENGINE_UPDATE_ATTEMPTER_H_

#include <time.h>

#include <memory>
#include <set>
#include <string>
#include <utility>
#include <vector>

#include <base/bind.h>
#include <base/time/time.h>
#include <gtest/gtest_prod.h>  // for FRIEND_TEST

#if USE_CHROME_NETWORK_PROXY
#include "update_engine/chrome_browser_proxy_resolver.h"
#endif  // USE_CHROME_NETWORK_PROXY
#include "update_engine/certificate_checker.h"
#include "update_engine/client_library/include/update_engine/update_status.h"
#include "update_engine/common/action_processor.h"
#include "update_engine/common/cpu_limiter.h"
#include "update_engine/omaha_request_params.h"
#include "update_engine/omaha_response_handler_action.h"
#include "update_engine/payload_consumer/download_action.h"
#include "update_engine/payload_consumer/postinstall_runner_action.h"
#include "update_engine/proxy_resolver.h"
#include "update_engine/service_observer_interface.h"
#include "update_engine/system_state.h"
#include "update_engine/update_manager/policy.h"
#include "update_engine/update_manager/update_manager.h"

namespace policy {
class PolicyProvider;
}

namespace chromeos_update_engine {

class UpdateEngineAdaptor;

class UpdateAttempter : public ActionProcessorDelegate,
                        public DownloadActionDelegate,
                        public CertificateChecker::Observer,
                        public PostinstallRunnerAction::DelegateInterface {
 public:
  using UpdateStatus = update_engine::UpdateStatus;
  using UpdateAttemptFlags = update_engine::UpdateAttemptFlags;
  static const int kMaxDeltaUpdateFailures;

  UpdateAttempter(SystemState* system_state, CertificateChecker* cert_checker);
  ~UpdateAttempter() override;

  // Further initialization to be done post construction.
  void Init();

  // Initiates scheduling of update checks.
  virtual void ScheduleUpdates();

  // Checks for update and, if a newer version is available, attempts to update
  // the system. Non-empty |in_app_version| or |in_update_url| prevents
  // automatic detection of the parameter.  |target_channel| denotes a
  // policy-mandated channel we are updating to, if not empty. If |obey_proxies|
  // is true, the update will likely respect Chrome's proxy setting. For
  // security reasons, we may still not honor them. |interactive| should be true
  // if this was called from the user (ie dbus).
  virtual void Update(const std::string& app_version,
                      const std::string& omaha_url,
                      const std::string& target_channel,
                      const std::string& target_version_prefix,
                      bool obey_proxies,
                      bool interactive);

  // ActionProcessorDelegate methods:
  void ProcessingDone(const ActionProcessor* processor,
                      ErrorCode code) override;
  void ProcessingStopped(const ActionProcessor* processor) override;
  void ActionCompleted(ActionProcessor* processor,
                       AbstractAction* action,
                       ErrorCode code) override;

  // PostinstallRunnerAction::DelegateInterface
  void ProgressUpdate(double progress) override;

  // Resets the current state to UPDATE_STATUS_IDLE.
  // Used by update_engine_client for restarting a new update without
  // having to reboot once the previous update has reached
  // UPDATE_STATUS_UPDATED_NEED_REBOOT state. This is used only
  // for testing purposes.
  virtual bool ResetStatus();

  // Returns the current status in the out param. Returns true on success.
  virtual bool GetStatus(update_engine::UpdateEngineStatus* out_status);

  // Runs chromeos-setgoodkernel, whose responsibility it is to mark the
  // currently booted partition has high priority/permanent/etc. The execution
  // is asynchronous. On completion, the action processor may be started
  // depending on the |start_action_processor_| field. Note that every update
  // attempt goes through this method.
  void UpdateBootFlags();

  // Called when the boot flags have been updated.
  void CompleteUpdateBootFlags(bool success);

  UpdateStatus status() const { return status_; }

  int http_response_code() const { return http_response_code_; }
  void set_http_response_code(int code) { http_response_code_ = code; }

  // Set flags that influence how updates and checks are performed.  These
  // influence all future checks and updates until changed or the device
  // reboots.
  void SetUpdateAttemptFlags(UpdateAttemptFlags flags) {
    update_attempt_flags_ = flags;
  }

  // Returns the update attempt flags that are in place for the current update
  // attempt.  These are cached at the start of an update attempt so that they
  // remain constant throughout the process.
  virtual UpdateAttemptFlags GetCurrentUpdateAttemptFlags() {
    return current_update_attempt_flags_;
  }

  // This is the internal entry point for going through an
  // update. If the current status is idle invokes Update.
  // This is called by the DBus implementation.
  // This returns true if an update check was started, false if a check or an
  // update was already in progress.
  virtual bool CheckForUpdate(const std::string& app_version,
                              const std::string& omaha_url,
                              UpdateAttemptFlags flags);

  // This is the internal entry point for going through a rollback. This will
  // attempt to run the postinstall on the non-active partition and set it as
  // the partition to boot from. If |powerwash| is True, perform a powerwash
  // as part of rollback. Returns True on success.
  bool Rollback(bool powerwash);

  // This is the internal entry point for checking if we can rollback.
  bool CanRollback() const;

  // This is the internal entry point for getting a rollback partition name,
  // if one exists. It returns the bootable rollback kernel device partition
  // name or empty string if none is available.
  BootControlInterface::Slot GetRollbackSlot() const;

  // Initiates a reboot if the current state is
  // UPDATED_NEED_REBOOT. Returns true on sucess, false otherwise.
  bool RebootIfNeeded();

  // DownloadActionDelegate methods:
  void BytesReceived(uint64_t bytes_progressed,
                     uint64_t bytes_received,
                     uint64_t total) override;

  // Returns that the update should be canceled when the download channel was
  // changed.
  bool ShouldCancel(ErrorCode* cancel_reason) override;

  void DownloadComplete() override;

  // Broadcasts the current status to all observers.
  void BroadcastStatus();

  // Returns the special flags to be added to ErrorCode values based on the
  // parameters used in the current update attempt.
  uint32_t GetErrorCodeFlags();

  // Called at update_engine startup to do various house-keeping.
  void UpdateEngineStarted();

  // Reloads the device policy from libbrillo. Note: This method doesn't
  // cause a real-time policy fetch from the policy server. It just reloads the
  // latest value that libbrillo has cached. libbrillo fetches the policies
  // from the server asynchronously at its own frequency.
  virtual void RefreshDevicePolicy();

  // Stores in |out_boot_time| the boottime (CLOCK_BOOTTIME) recorded at the
  // time of the last successful update in the current boot. Returns false if
  // there wasn't a successful update in the current boot.
  virtual bool GetBootTimeAtUpdate(base::Time *out_boot_time);

  // Returns a version OS version that was being used before the last reboot,
  // and if that reboot happended to be into an update (current version).
  // This will return an empty string otherwise.
  std::string const& GetPrevVersion() const { return prev_version_; }

  // Returns the number of consecutive failed update checks.
  virtual unsigned int consecutive_failed_update_checks() const {
    return consecutive_failed_update_checks_;
  }

  // Returns the poll interval dictated by Omaha, if provided; zero otherwise.
  virtual unsigned int server_dictated_poll_interval() const {
    return server_dictated_poll_interval_;
  }

  // Sets a callback to be used when either a forced update request is received
  // (first argument set to true) or cleared by an update attempt (first
  // argument set to false). The callback further encodes whether the forced
  // check is an interactive one (second argument set to true). Takes ownership
  // of the callback object. A null value disables callback on these events.
  // Note that only one callback can be set, so effectively at most one client
  // can be notified.
  virtual void set_forced_update_pending_callback(
      base::Callback<void(bool, bool)>*  // NOLINT(readability/function)
      callback) {
    forced_update_pending_callback_.reset(callback);
  }

  // Returns true if we should allow updates from any source. In official builds
  // we want to restrict updates to known safe sources, but under certain
  // conditions it's useful to allow updating from anywhere (e.g. to allow
  // 'cros flash' to function properly).
  virtual bool IsAnyUpdateSourceAllowed();

  // Add and remove a service observer.
  void AddObserver(ServiceObserverInterface* observer) {
    service_observers_.insert(observer);
  }
  void RemoveObserver(ServiceObserverInterface* observer) {
    service_observers_.erase(observer);
  }

  const std::set<ServiceObserverInterface*>& service_observers() {
    return service_observers_;
  }

  // Remove all the observers.
  void ClearObservers() { service_observers_.clear(); }

 private:
  // Update server URL for automated lab test.
  static const char* const kTestUpdateUrl;

  // Friend declarations for testing purposes.
  friend class UpdateAttempterUnderTest;
  friend class UpdateAttempterTest;
  FRIEND_TEST(UpdateAttempterTest, ActionCompletedDownloadTest);
  FRIEND_TEST(UpdateAttempterTest, ActionCompletedErrorTest);
  FRIEND_TEST(UpdateAttempterTest, ActionCompletedOmahaRequestTest);
  FRIEND_TEST(UpdateAttempterTest, BootTimeInUpdateMarkerFile);
  FRIEND_TEST(UpdateAttempterTest, BroadcastCompleteDownloadTest);
  FRIEND_TEST(UpdateAttempterTest, ChangeToDownloadingOnReceivedBytesTest);
  FRIEND_TEST(UpdateAttempterTest, CreatePendingErrorEventTest);
  FRIEND_TEST(UpdateAttempterTest, CreatePendingErrorEventResumedTest);
  FRIEND_TEST(UpdateAttempterTest, DisableDeltaUpdateIfNeededTest);
  FRIEND_TEST(UpdateAttempterTest, DownloadProgressAccumulationTest);
  FRIEND_TEST(UpdateAttempterTest, MarkDeltaUpdateFailureTest);
  FRIEND_TEST(UpdateAttempterTest, PingOmahaTest);
  FRIEND_TEST(UpdateAttempterTest, ReportDailyMetrics);
  FRIEND_TEST(UpdateAttempterTest, ScheduleErrorEventActionNoEventTest);
  FRIEND_TEST(UpdateAttempterTest, ScheduleErrorEventActionTest);
  FRIEND_TEST(UpdateAttempterTest, TargetVersionPrefixSetAndReset);
  FRIEND_TEST(UpdateAttempterTest, UpdateAttemptFlagsCachedAtUpdateStart);
  FRIEND_TEST(UpdateAttempterTest, UpdateDeferredByPolicyTest);
  FRIEND_TEST(UpdateAttempterTest, UpdateIsNotRunningWhenUpdateAvailable);
  FRIEND_TEST(UpdateAttempterTest, UpdateTest);

  // CertificateChecker::Observer method.
  // Report metrics about the certificate being checked.
  void CertificateChecked(ServerToCheck server_to_check,
                          CertificateCheckResult result) override;

  // Checks if it's more than 24 hours since daily metrics were last
  // reported and, if so, reports daily metrics. Returns |true| if
  // metrics were reported, |false| otherwise.
  bool CheckAndReportDailyMetrics();

  // Calculates and reports the age of the currently running OS. This
  // is defined as the age of the /etc/lsb-release file.
  void ReportOSAge();

  // Sets the status to the given status and notifies a status update over dbus.
  void SetStatusAndNotify(UpdateStatus status);

  // Creates an error event object in |error_event_| to be included in an
  // OmahaRequestAction once the current action processor is done.
  void CreatePendingErrorEvent(AbstractAction* action, ErrorCode code);

  // If there's a pending error event allocated in |error_event_|, schedules an
  // OmahaRequestAction with that event in the current processor, clears the
  // pending event, updates the status and returns true. Returns false
  // otherwise.
  bool ScheduleErrorEventAction();

  // Schedules an event loop callback to start the action processor. This is
  // scheduled asynchronously to unblock the event loop.
  void ScheduleProcessingStart();

  // Checks if a full update is needed and forces it by updating the Omaha
  // request params.
  void DisableDeltaUpdateIfNeeded();

  // If this was a delta update attempt that failed, count it so that a full
  // update can be tried when needed.
  void MarkDeltaUpdateFailure();

  ProxyResolver* GetProxyResolver() {
#if USE_CHROME_NETWORK_PROXY
    return obeying_proxies_ ?
        reinterpret_cast<ProxyResolver*>(&chrome_proxy_resolver_) :
        reinterpret_cast<ProxyResolver*>(&direct_proxy_resolver_);
#else
    return &direct_proxy_resolver_;
#endif  // USE_CHROME_NETWORK_PROXY
  }

  // Sends a ping to Omaha.
  // This is used after an update has been applied and we're waiting for the
  // user to reboot.  This ping helps keep the number of actives count
  // accurate in case a user takes a long time to reboot the device after an
  // update has been applied.
  void PingOmaha();

  // Helper method of Update() to calculate the update-related parameters
  // from various sources and set the appropriate state. Please refer to
  // Update() method for the meaning of the parametes.
  bool CalculateUpdateParams(const std::string& app_version,
                             const std::string& omaha_url,
                             const std::string& target_channel,
                             const std::string& target_version_prefix,
                             bool obey_proxies,
                             bool interactive);

  // Calculates all the scattering related parameters (such as waiting period,
  // which type of scattering is enabled, etc.) and also updates/deletes
  // the corresponding prefs file used in scattering. Should be called
  // only after the device policy has been loaded and set in the system_state_.
  void CalculateScatteringParams(bool is_interactive);

  // Sets a random value for the waiting period to wait for before downloading
  // an update, if one available. This value will be upperbounded by the
  // scatter factor value specified from policy.
  void GenerateNewWaitingPeriod();

  // Helper method of Update() and Rollback() to construct the sequence of
  // actions to be performed for the postinstall.
  // |previous_action| is the previous action to get
  // bonded with the install_plan that gets passed to postinstall.
  void BuildPostInstallActions(InstallPlanAction* previous_action);

  // Helper method of Update() to construct the sequence of actions to
  // be performed for an update check. Please refer to
  // Update() method for the meaning of the parameters.
  void BuildUpdateActions(bool interactive);

  // Decrements the count in the kUpdateCheckCountFilePath.
  // Returns True if successfully decremented, false otherwise.
  bool DecrementUpdateCheckCount();

  // Starts p2p and performs housekeeping. Returns true only if p2p is
  // running and housekeeping was done.
  bool StartP2PAndPerformHousekeeping();

  // Calculates whether peer-to-peer should be used. Sets the
  // |use_p2p_to_download_| and |use_p2p_to_share_| parameters
  // on the |omaha_request_params_| object.
  void CalculateP2PParams(bool interactive);

  // Starts P2P if it's enabled and there are files to actually share.
  // Called only at program startup. Returns true only if p2p was
  // started and housekeeping was performed.
  bool StartP2PAtStartup();

  // Writes to the processing completed marker. Does nothing if
  // |update_completed_marker_| is empty.
  void WriteUpdateCompletedMarker();

  // Reboots the system directly by calling /sbin/shutdown. Returns true on
  // success.
  bool RebootDirectly();

  // Callback for the async UpdateCheckAllowed policy request. If |status| is
  // |EvalStatus::kSucceeded|, either runs or suppresses periodic update checks,
  // based on the content of |params|. Otherwise, retries the policy request.
  void OnUpdateScheduled(
      chromeos_update_manager::EvalStatus status,
      const chromeos_update_manager::UpdateCheckParams& params);

  // Updates the time an update was last attempted to the current time.
  void UpdateLastCheckedTime();

  // Checks whether we need to clear the rollback-happened preference after
  // policy is available again.
  void UpdateRollbackHappened();

  // Returns whether an update is currently running or scheduled.
  bool IsUpdateRunningOrScheduled();

  // Last status notification timestamp used for throttling. Use monotonic
  // TimeTicks to ensure that notifications are sent even if the system clock is
  // set back in the middle of an update.
  base::TimeTicks last_notify_time_;

  std::vector<std::shared_ptr<AbstractAction>> actions_;
  std::unique_ptr<ActionProcessor> processor_;

  // External state of the system outside the update_engine process
  // carved out separately to mock out easily in unit tests.
  SystemState* system_state_;

  // Pointer to the certificate checker instance to use.
  CertificateChecker* cert_checker_;

  // The list of services observing changes in the updater.
  std::set<ServiceObserverInterface*> service_observers_;

  // Pointer to the OmahaResponseHandlerAction in the actions_ vector.
  std::shared_ptr<OmahaResponseHandlerAction> response_handler_action_;

  // Pointer to the DownloadAction in the actions_ vector.
  std::shared_ptr<DownloadAction> download_action_;

  // Pointer to the preferences store interface. This is just a cached
  // copy of system_state->prefs() because it's used in many methods and
  // is convenient this way.
  PrefsInterface* prefs_ = nullptr;

  // Pending error event, if any.
  std::unique_ptr<OmahaEvent> error_event_;

  // If we should request a reboot even tho we failed the update
  bool fake_update_success_ = false;

  // HTTP server response code from the last HTTP request action.
  int http_response_code_ = 0;

  // CPU limiter during the update.
  CPULimiter cpu_limiter_;

  // For status:
  UpdateStatus status_{UpdateStatus::IDLE};
  double download_progress_ = 0.0;
  int64_t last_checked_time_ = 0;
  std::string prev_version_;
  std::string new_version_ = "0.0.0.0";
  std::string new_system_version_;
  uint64_t new_payload_size_ = 0;
  // Flags influencing all periodic update checks
  UpdateAttemptFlags update_attempt_flags_ = UpdateAttemptFlags::kNone;
  // Flags influencing the currently in-progress check (cached at the start of
  // the update check).
  UpdateAttemptFlags current_update_attempt_flags_ = UpdateAttemptFlags::kNone;

  // Common parameters for all Omaha requests.
  OmahaRequestParams* omaha_request_params_ = nullptr;

  // Number of consecutive manual update checks we've had where we obeyed
  // Chrome's proxy settings.
  int proxy_manual_checks_ = 0;

  // If true, this update cycle we are obeying proxies
  bool obeying_proxies_ = true;

  // Our two proxy resolvers
  DirectProxyResolver direct_proxy_resolver_;
#if USE_CHROME_NETWORK_PROXY
  ChromeBrowserProxyResolver chrome_proxy_resolver_;
#endif  // USE_CHROME_NETWORK_PROXY

  // Originally, both of these flags are false. Once UpdateBootFlags is called,
  // |update_boot_flags_running_| is set to true. As soon as UpdateBootFlags
  // completes its asynchronous run, |update_boot_flags_running_| is reset to
  // false and |updated_boot_flags_| is set to true. From that point on there
  // will be no more changes to these flags.
  //
  // True if UpdateBootFlags has completed.
  bool updated_boot_flags_ = false;
  // True if UpdateBootFlags is running.
  bool update_boot_flags_running_ = false;

  // True if the action processor needs to be started by the boot flag updater.
  bool start_action_processor_ = false;

  // Used for fetching information about the device policy.
  std::unique_ptr<policy::PolicyProvider> policy_provider_;

  // The current scatter factor as found in the policy setting.
  base::TimeDelta scatter_factor_;

  // The number of consecutive failed update checks. Needed for calculating the
  // next update check interval.
  unsigned int consecutive_failed_update_checks_ = 0;

  // The poll interval (in seconds) that was dictated by Omaha, if any; zero
  // otherwise. This is needed for calculating the update check interval.
  unsigned int server_dictated_poll_interval_ = 0;

  // Tracks whether we have scheduled update checks.
  bool waiting_for_scheduled_check_ = false;

  // A callback to use when a forced update request is either received (true) or
  // cleared by an update attempt (false). The second argument indicates whether
  // this is an interactive update, and its value is significant iff the first
  // argument is true.
  std::unique_ptr<base::Callback<void(bool, bool)>>
      forced_update_pending_callback_;

  // The |app_version| and |omaha_url| parameters received during the latest
  // forced update request. They are retrieved for use once the update is
  // actually scheduled.
  std::string forced_app_version_;
  std::string forced_omaha_url_;

  DISALLOW_COPY_AND_ASSIGN(UpdateAttempter);
};

}  // namespace chromeos_update_engine

#endif  // UPDATE_ENGINE_UPDATE_ATTEMPTER_H_