/*
 * Copyright 2018 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.
 */

#pragma once

#include "Thread.h"

#include <cstdint>
#include <mutex>
#include <string>
#include <vector>
#include <chrono>

namespace swappy {

class Settings {
  private:
    // Allows construction with std::unique_ptr from a static method, but disallows construction
    // outside of the class since no one else can construct a ConstructorTag
    struct ConstructorTag {
    };
  public:
    explicit Settings(ConstructorTag) {};

    static Settings *getInstance();

    using Listener = std::function<void()>;
    void addListener(Listener listener);

    void setRefreshPeriod(std::chrono::nanoseconds period);
    void setSwapIntervalNS(uint64_t swap_ns);
    void setUseAffinity(bool);

    std::chrono::nanoseconds getRefreshPeriod() const;
    uint64_t getSwapIntervalNS() const;
    bool getUseAffinity() const;

  private:
    void notifyListeners();

    mutable std::mutex mMutex;
    std::vector<Listener> mListeners GUARDED_BY(mMutex);

    std::chrono::nanoseconds
        mRefreshPeriod GUARDED_BY(mMutex) = std::chrono::nanoseconds{12'345'678};
    uint64_t mSwapIntervalNS GUARDED_BY(mMutex) = 16666667L;
    bool mUseAffinity GUARDED_BY(mMutex) = true;
};

} // namespace swappy