/**
 * Copyright (c) 2020, 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.
 */

#ifndef CPP_WATCHDOG_SERVER_SRC_WATCHDOGSERVICEHELPER_H_
#define CPP_WATCHDOG_SERVER_SRC_WATCHDOGSERVICEHELPER_H_

#include "WatchdogProcessService.h"

#include <android-base/result.h>
#include <android/automotive/watchdog/TimeoutLength.h>
#include <android/automotive/watchdog/internal/ICarWatchdogServiceForSystem.h>
#include <android/automotive/watchdog/internal/PackageInfo.h>
#include <android/automotive/watchdog/internal/PackageIoOveruseStats.h>
#include <binder/IBinder.h>
#include <binder/Status.h>
#include <gtest/gtest_prod.h>
#include <utils/Mutex.h>
#include <utils/StrongPointer.h>

#include <shared_mutex>

namespace android {
namespace automotive {
namespace watchdog {

class ServiceManager;

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

class WatchdogServiceHelperPeer;

}  // namespace internal

class IWatchdogServiceHelper : public android::IBinder::DeathRecipient {
public:
    virtual android::binder::Status registerService(
            const android::sp<
                    android::automotive::watchdog::internal::ICarWatchdogServiceForSystem>&
                    service) = 0;
    virtual android::binder::Status unregisterService(
            const android::sp<
                    android::automotive::watchdog::internal::ICarWatchdogServiceForSystem>&
                    service) = 0;

    // Helper methods for APIs in ICarWatchdogServiceForSystem.aidl.
    virtual android::binder::Status checkIfAlive(const android::wp<android::IBinder>& who,
                                                 int32_t sessionId,
                                                 TimeoutLength timeout) const = 0;
    virtual android::binder::Status prepareProcessTermination(
            const android::wp<android::IBinder>& who) = 0;
    virtual android::binder::Status getPackageInfosForUids(
            const std::vector<int32_t>& uids, const std::vector<std::string>& vendorPackagePrefixes,
            std::vector<android::automotive::watchdog::internal::PackageInfo>* packageInfos) = 0;
    virtual android::binder::Status latestIoOveruseStats(
            const std::vector<android::automotive::watchdog::internal::PackageIoOveruseStats>&
                    packageIoOveruseStats) = 0;
    virtual android::binder::Status resetResourceOveruseStats(
            const std::vector<std::string>& packageNames) = 0;
    virtual android::binder::Status getTodayIoUsageStats(
            std::vector<android::automotive::watchdog::internal::UserPackageIoUsageStats>*
                    userPackageIoUsageStats) = 0;

protected:
    virtual android::base::Result<void> init(
            const android::sp<WatchdogProcessService>& watchdogProcessService) = 0;
    virtual void terminate() = 0;

private:
    friend class ServiceManager;
};

// WatchdogServiceHelper implements the helper functions for the outbound API requests to
// the CarWatchdogService. This class doesn't handle the inbound APIs requests from
// CarWatchdogService except the registration APIs.
class WatchdogServiceHelper final : public IWatchdogServiceHelper {
public:
    WatchdogServiceHelper() : mService(nullptr), mWatchdogProcessService(nullptr) {}
    ~WatchdogServiceHelper();

    android::binder::Status registerService(
            const android::sp<
                    android::automotive::watchdog::internal::ICarWatchdogServiceForSystem>& service)
            override;
    android::binder::Status unregisterService(
            const android::sp<
                    android::automotive::watchdog::internal::ICarWatchdogServiceForSystem>& service)
            override;
    void binderDied(const android::wp<android::IBinder>& who) override;

    // Helper methods for ICarWatchdogServiceForSystem.aidl.
    android::binder::Status checkIfAlive(const android::wp<android::IBinder>& who,
                                         int32_t sessionId, TimeoutLength timeout) const override;
    android::binder::Status prepareProcessTermination(
            const android::wp<android::IBinder>& who) override;
    android::binder::Status getPackageInfosForUids(
            const std::vector<int32_t>& uids, const std::vector<std::string>& vendorPackagePrefixes,
            std::vector<android::automotive::watchdog::internal::PackageInfo>* packageInfos);
    android::binder::Status latestIoOveruseStats(
            const std::vector<android::automotive::watchdog::internal::PackageIoOveruseStats>&
                    packageIoOveruseStats);
    android::binder::Status resetResourceOveruseStats(const std::vector<std::string>& packageNames);
    android::binder::Status getTodayIoUsageStats(
            std::vector<android::automotive::watchdog::internal::UserPackageIoUsageStats>*
                    userPackageIoUsageStats);

protected:
    android::base::Result<void> init(
            const android::sp<WatchdogProcessService>& watchdogProcessService);
    void terminate();

private:
    void unregisterServiceLocked();

    mutable std::shared_mutex mRWMutex;
    android::sp<android::automotive::watchdog::internal::ICarWatchdogServiceForSystem> mService
            GUARDED_BY(mRWMutex);
    android::sp<WatchdogProcessService> mWatchdogProcessService;

    friend class ServiceManager;

    // For unit tests.
    friend class internal::WatchdogServiceHelperPeer;
    FRIEND_TEST(WatchdogServiceHelperTest, TestInit);
    FRIEND_TEST(WatchdogServiceHelperTest,
                TestErrorOnInitWithErrorFromWatchdogProcessServiceRegistration);
    FRIEND_TEST(WatchdogServiceHelperTest, TestErrorOnInitWithNullWatchdogProcessServiceInstance);
    FRIEND_TEST(WatchdogServiceHelperTest, TestTerminate);
};

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

#endif  // CPP_WATCHDOG_SERVER_SRC_WATCHDOGSERVICEHELPER_H_