// Copyright 2020 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_OPTIMIZATION_GUIDE_CORE_DELIVERY_OPTIMIZATION_TARGET_MODEL_OBSERVER_H_
#define COMPONENTS_OPTIMIZATION_GUIDE_CORE_DELIVERY_OPTIMIZATION_TARGET_MODEL_OBSERVER_H_

#include "base/files/file_path.h"
#include "base/observer_list_types.h"
#include "base/types/optional_ref.h"
#include "components/optimization_guide/core/delivery/model_info.h"
#include "components/optimization_guide/proto/models.pb.h"

namespace optimization_guide {

// Observes `optimization_guide::OptimizationGuideDecider` for updates to models
// for a particular optimization target.
class OptimizationTargetModelObserver : public base::CheckedObserver {
 public:
  // Invoked when a model for `optimization_target` has been updated. It is
  // guaranteed that this method will only be invoked for targets that `this` is
  // added as an observer for.
  //
  // When this observer is first added, this function will be called with the
  // model if it is already on device.
  //
  // When model was stopped to be served from the optimization guide server, and
  // removed from on-device store, this will be called with null `model_info`.
  // The observers should stop using the model, and remove any persistent state
  // about the `optimization_target`, if applicable.
  virtual void OnModelUpdated(
      proto::OptimizationTarget optimization_target,
      base::optional_ref<const ModelInfo> model_info) = 0;
};

}  // namespace optimization_guide

#endif  // COMPONENTS_OPTIMIZATION_GUIDE_CORE_DELIVERY_OPTIMIZATION_TARGET_MODEL_OBSERVER_H_