/*
 * Copyright (C) 2021 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 <inttypes.h>

#include <array>
#include <chrono>
#include <deque>
#include <random>
#include <vector>

#include "AdaptiveCpuConfig.h"
#include "CpuFrequencyReader.h"
#include "Device.h"
#include "ThrottleDecision.h"
#include "WorkDurationProcessor.h"

namespace aidl {
namespace google {
namespace hardware {
namespace power {
namespace impl {
namespace pixel {

// Currently Adaptive CPU is targeted to only raven/oriole, so we can hardcode the CPU architecture.
// If we extend to other architectures, this will have to vary per-device or be dynamically loaded.
constexpr uint32_t NUM_CPU_CORES = 8;
constexpr uint32_t NUM_CPU_POLICIES = 3;
constexpr std::array<uint32_t, NUM_CPU_POLICIES> CPU_POLICY_INDICES{0, 4, 6};

struct ModelInput {
    std::array<double, NUM_CPU_POLICIES> cpuPolicyAverageFrequencyHz;
    std::array<double, NUM_CPU_CORES> cpuCoreIdleTimesPercentage;
    WorkDurationFeatures workDurationFeatures;
    ThrottleDecision previousThrottleDecision;
    Device device;

    bool SetCpuFreqiencies(
            const std::vector<CpuPolicyAverageFrequency> &cpuPolicyAverageFrequencies);

    void LogToAtrace() const;

    bool operator==(const ModelInput &other) const {
        return cpuPolicyAverageFrequencyHz == other.cpuPolicyAverageFrequencyHz &&
               cpuCoreIdleTimesPercentage == other.cpuCoreIdleTimesPercentage &&
               workDurationFeatures == other.workDurationFeatures &&
               previousThrottleDecision == other.previousThrottleDecision;
    }
};

class Model {
  public:
    Model()
        : mShouldRandomThrottleDistribution(0, 1),
          mRandomThrottleDistribution(static_cast<uint32_t>(ThrottleDecision::FIRST),
                                      static_cast<uint32_t>(ThrottleDecision::LAST)) {}
    ThrottleDecision Run(const std::deque<ModelInput> &modelInputs,
                         const AdaptiveCpuConfig &config);

  private:
    std::default_random_engine mGenerator;
    std::uniform_real_distribution<double> mShouldRandomThrottleDistribution;
    std::uniform_int_distribution<uint32_t> mRandomThrottleDistribution;

    ThrottleDecision RunDecisionTree(const std::deque<ModelInput> &modelInputs);
};

}  // namespace pixel
}  // namespace impl
}  // namespace power
}  // namespace hardware
}  // namespace google
}  // namespace aidl