/*
 * 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 "UidCpuStatsCollector.h"
#include "UidProcStatsCollector.h"
#include "UidStatsCollectorBase.h"

#include <android-base/result.h>
#include <utils/Mutex.h>
#include <utils/RefBase.h>
#include <utils/StrongPointer.h>

#include <vector>

namespace android {
namespace automotive {
namespace watchdog {

// Forward declaration for testing use only.
namespace internal {

class UidStatsCollectorPeer;

}  // namespace internal

struct UidStats : public UidBaseStats {
    int64_t cpuTimeMillis = 0;
    UidProcStats procStats = {};
};

// Collector/Aggregator for per-UID I/O and proc stats.
class UidStatsCollectorInterface : virtual public UidStatsCollectorBaseInterface {
public:
    // Returns the latest per-uid I/O and proc stats.
    virtual const std::vector<UidStats> latestStats() const = 0;
    // Returns the delta of per-uid I/O and proc stats since the last before collection.
    virtual const std::vector<UidStats> deltaStats() const = 0;
};

class UidStatsCollector final : public UidStatsCollectorBase, public UidStatsCollectorInterface {
public:
    UidStatsCollector() :
          mUidCpuStatsCollector(android::sp<UidCpuStatsCollector>::make()),
          mUidProcStatsCollector(android::sp<UidProcStatsCollector>::make()) {}

    void init() override {
        Mutex::Autolock lock(mMutex);
        mUidCpuStatsCollector->init();
        mUidIoStatsCollector->init();
        mUidProcStatsCollector->init();
    }

    android::base::Result<void> collect() override;

    const std::vector<UidStats> latestStats() const override {
        Mutex::Autolock lock(mMutex);
        return mLatestStats;
    }

    const std::vector<UidStats> deltaStats() const override {
        Mutex::Autolock lock(mMutex);
        return mDeltaStats;
    }

    const std::vector<UidBaseStats> latestBaseStats() const override {
        Mutex::Autolock lock(mMutex);
        std::vector<UidBaseStats> latestBaseStats{mLatestStats.begin(), mLatestStats.end()};
        return latestBaseStats;
    }

    const std::vector<UidBaseStats> deltaBaseStats() const override {
        Mutex::Autolock lock(mMutex);
        std::vector<UidBaseStats> deltaBaseStats{mDeltaStats.begin(), mDeltaStats.end()};
        return deltaBaseStats;
    }

    bool enabled() const override {
        return UidStatsCollectorBase::enabled() || mUidProcStatsCollector->enabled();
    }

private:
    std::vector<UidStats> process(
            const std::unordered_map<uid_t, UidIoStats>& uidIoStatsByUid,
            const std::unordered_map<uid_t, UidProcStats>& uidProcStatsByUid,
            const std::unordered_map<uid_t, int64_t>& cpuTimeMillisByUid) const;

    android::sp<UidCpuStatsCollectorInterface> mUidCpuStatsCollector GUARDED_BY(mMutex);

    android::sp<UidProcStatsCollectorInterface> mUidProcStatsCollector GUARDED_BY(mMutex);

    std::vector<UidStats> mLatestStats GUARDED_BY(mMutex);

    std::vector<UidStats> mDeltaStats GUARDED_BY(mMutex);

    // For unit tests.
    friend class internal::UidStatsCollectorPeer;
};

}  // namespace watchdog
}  // namespace automotive
}  // namespace android