// Copyright 2018 The Chromium OS 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 POWER_MANAGER_POWERD_POLICY_USER_PROXIMITY_VOTING_H_
#define POWER_MANAGER_POWERD_POLICY_USER_PROXIMITY_VOTING_H_

#include "power_manager/common/power_constants.h"

#include <unordered_map>

#include <base/macros.h>

namespace power_manager {
namespace policy {

// Aggregates votes from one or more sensors about the user's physical
// proximity to the device.
class UserProximityVoting {
 public:
  UserProximityVoting();
  UserProximityVoting(const UserProximityVoting&) = delete;
  UserProximityVoting& operator=(const UserProximityVoting&) = delete;

  ~UserProximityVoting();

  // Sets the vote of sensor |id| to |vote|. The sensor is added
  // to the voting pool if no previous vote for |id| was registered.
  // Returns true if the consensus changes due to |vote|.
  bool Vote(int id, UserProximity vote);

  // Returns the current consensus among all the sensors in this voting pool.
  // NEAR is returned if at least one sensor is claiming proximity, otherwise
  // FAR is returned. UNKNOWN is returned iff there are no sensors.
  UserProximity GetVote() const;

 private:
  UserProximity CalculateVote() const;

  std::unordered_map<int, UserProximity> votes_;
  UserProximity consensus_ = UserProximity::UNKNOWN;
};

}  // namespace policy
}  // namespace power_manager

#endif  //  POWER_MANAGER_POWERD_POLICY_USER_PROXIMITY_VOTING_H_