// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_SUPERVISED_USER_CORE_BROWSER_SUPERVISED_USER_METRICS_SERVICE_H_
#define COMPONENTS_SUPERVISED_USER_CORE_BROWSER_SUPERVISED_USER_METRICS_SERVICE_H_

#include <memory>
#include <optional>

#include "base/callback_list.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/raw_ref.h"
#include "base/scoped_observation.h"
#include "base/timer/timer.h"
#include "components/keyed_service/core/keyed_service.h"
#include "components/supervised_user/core/browser/device_parental_controls.h"
#include "components/supervised_user/core/browser/supervised_user_synthetic_field_trial_service_delegate.h"
#include "components/supervised_user/core/browser/supervised_user_url_filtering_service.h"

class PrefRegistrySimple;
class PrefService;

namespace base {
class Time;
}  // namespace base

namespace supervised_user {

// Service to initialize and control metric recorders of supervised users.
// Records metrics daily, or when supervision settings change.
class SupervisedUserMetricsService
    : public KeyedService,
      public SupervisedUserUrlFilteringService::Observer {
 public:
  // This enum describes whether the approved list or blocked list is used on
  // Chrome on Chrome OS, which is set by Family Link App or at
  // families.google.com/families via "manage sites" setting. This is also
  // referred to as manual behavior/filter as parent need to add everything one
  // by one. These values are logged to UMA. Entries should not be renumbered
  // and numeric values should never be reused. Please keep in sync with
  // "FamilyLinkManagedSiteList" in src/tools/metrics/histograms/enums.xml.
  enum class ManagedSiteList {
    // The web filter has both empty blocked and approved list.
    kEmpty = 0,

    // The web filter has approved list only.
    kApprovedListOnly = 1,

    // The web filter has blocked list only.
    kBlockedListOnly = 2,

    // The web filter has both approved list and blocked list.
    kBoth = 3,

    // Used for UMA. Update kMaxValue to the last value. Add future entries
    // above this comment. Sync with enums.xml.
    kMaxValue = kBoth,
  };

  // Delegate for recording metrics relating to extensions for supervised users
  // such as metrics that should be recorded daily.
  class SupervisedUserMetricsServiceExtensionDelegate {
   public:
    virtual ~SupervisedUserMetricsServiceExtensionDelegate() = default;
    // Record metrics relating to extensions.
    // Returns true if new metrics where recorded.
    virtual bool RecordExtensionsMetrics() = 0;
  };

  static void RegisterProfilePrefs(PrefRegistrySimple* registry);
  // Returns the day id for a given time for testing.
  static int GetDayIdForTesting(base::Time time);

  SupervisedUserMetricsService(
      PrefService* pref_service,
      SupervisedUserUrlFilteringService& url_filtering_service,
      DeviceParentalControls& device_parental_controls,
      std::unique_ptr<SupervisedUserMetricsServiceExtensionDelegate>
          extensions_metrics_delegate,
      std::unique_ptr<SynteticFieldTrialDelegate>
          synthetic_field_trial_delegate);
  SupervisedUserMetricsService(const SupervisedUserMetricsService&) = delete;
  SupervisedUserMetricsService& operator=(const SupervisedUserMetricsService&) =
      delete;
  ~SupervisedUserMetricsService() override;

  // KeyedService:
  void Shutdown() override;

 private:
  // SupervisedUserUrlFilteringService::Observer:
  void OnUrlFilteringServiceChanged() override;

  void OnDeviceParentalControlsChanged(
      const DeviceParentalControls& device_parental_controls);

  // Helper function to check if a new day has arrived.
  void CheckForNewDay();
  // Returns true if metrics were emitted. Dispatches to one of the below
  // functions depending on the user type.
  bool TryEmittingMetricsAndRecordCurrentDay();
  bool TryEmittingFamilyLinkMetrics();
  bool TryEmittingSupervisedUserMetrics();

  // Clears cache of last recorded metrics. Subsequent `::TryEmittingMetrics`
  // will emit all metrics (for eligible users)
  void ClearMetricsCache();

  // Records the current day's metrics, to avoid repetitions.
  void RecordCurrentDay();

  const raw_ptr<PrefService> pref_service_;
  raw_ref<const SupervisedUserUrlFilteringService> url_filtering_service_;
  const raw_ref<const DeviceParentalControls> device_parental_controls_;
  std::unique_ptr<SupervisedUserMetricsServiceExtensionDelegate>
      extensions_metrics_delegate_;
  std::unique_ptr<SynteticFieldTrialDelegate> synthetic_field_trial_delegate_;

  // A periodic timer that checks if a new day has arrived.
  base::RepeatingTimer timer_;

  // Cache of last recorded values of FamilyLinkUrlFilter to avoid duplicated
  // emissions.
  std::optional<WebFilterType> last_recorded_family_link_web_filter_type_;
  std::optional<UrlFilteringDelegate::Statistics> last_recorded_statistics_;
  std::optional<WebFilterType> last_recorded_supervised_user_web_filter_type_;
  base::ScopedObservation<SupervisedUserUrlFilteringService,
                          SupervisedUserUrlFilteringService::Observer>
      url_filtering_service_observation_{this};

  base::CallbackListSubscription device_parental_controls_subscription_;
};
}  // namespace supervised_user

#endif  // COMPONENTS_SUPERVISED_USER_CORE_BROWSER_SUPERVISED_USER_METRICS_SERVICE_H_