text: // Copyright 2017 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef COMPONENTS_FEATURE_ENGAGEMENT_INTERNAL_EVENT_MODEL_IMPL_H_
  #define COMPONENTS_FEATURE_ENGAGEMENT_INTERNAL_EVENT_MODEL_IMPL_H_
  
  #include <map>
  #include <memory>
  #include <string>
  #include <vector>
  
  #include "base/macros.h"
  #include "base/memory/weak_ptr.h"
  #include "components/feature_engagement/internal/event_model.h"
  #include "components/feature_engagement/internal/proto/feature_event.pb.h"
  
  namespace feature_engagement {
  class EventStorageValidator;
  class EventStore;
  
  // A EventModelImpl provides the default implementation of the EventModel.
  class EventModelImpl : public EventModel {
   public:
    EventModelImpl(std::unique_ptr<EventStore> store,
                   std::unique_ptr<EventStorageValidator> storage_validator);
    ~EventModelImpl() override;
  
    // EventModel implementation.
    void Initialize(OnModelInitializationFinished callback,
                    uint32_t current_day) override;
    bool IsReady() const override;
    const Event* GetEvent(const std::string& event_name) const override;
    uint32_t GetEventCount(const std::string& event_name,
                           uint32_t current_day,
                           uint32_t window_size) const override;
    void IncrementEvent(const std::string& event_name,
                        uint32_t current_day) override;
  
   private:
    // Callback for loading the underlying store.
    void OnStoreLoaded(OnModelInitializationFinished callback,
                       uint32_t current_day,
                       bool success,
                       std::unique_ptr<std::vector<Event>> events);
  
    // Internal version for getting the non-const version of a stored Event.
    // Creates the event if it is not already stored.
    Event& GetNonConstEvent(const std::string& event_name);
  
    // The underlying store for all events.
    std::unique_ptr<EventStore> store_;
  
    // A utility for checking whether new events should be stored and for whether
    // old events should be kept.
    std::unique_ptr<EventStorageValidator> storage_validator_;
  
    // An in-memory representation of all events.
    std::map<std::string, Event> events_;
  
    // Whether the model has been fully initialized.
    bool ready_;
  
    base::WeakPtrFactory<EventModelImpl> weak_factory_{this};
  
    DISALLOW_COPY_AND_ASSIGN(EventModelImpl);
  };
  
  }  // namespace feature_engagement
  
  #endif  // COMPONENTS_FEATURE_ENGAGEMENT_INTERNAL_EVENT_MODEL_IMPL_H_
  