/*
 * 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.
 */

#ifndef android_hardware_automotive_vehicle_aidl_impl_vhal_include_DefaultVehicleHal_H_
#define android_hardware_automotive_vehicle_aidl_impl_vhal_include_DefaultVehicleHal_H_

#include <ConnectedClient.h>
#include <ParcelableUtils.h>
#include <PendingRequestPool.h>
#include <RecurrentTimer.h>
#include <SubscriptionManager.h>

#include <ConcurrentQueue.h>
#include <IVehicleHardware.h>
#include <VehicleUtils.h>
#include <aidl/android/hardware/automotive/vehicle/BnVehicle.h>
#include <android-base/expected.h>
#include <android-base/thread_annotations.h>
#include <android/binder_auto_utils.h>

#include <memory>
#include <mutex>
#include <shared_mutex>
#include <unordered_map>
#include <vector>

namespace android {
namespace hardware {
namespace automotive {
namespace vehicle {

class DefaultVehicleHal final : public aidl::android::hardware::automotive::vehicle::BnVehicle {
  public:
    using CallbackType =
            std::shared_ptr<aidl::android::hardware::automotive::vehicle::IVehicleCallback>;

    explicit DefaultVehicleHal(std::unique_ptr<IVehicleHardware> hardware);

    ~DefaultVehicleHal();

    ndk::ScopedAStatus getAllPropConfigs(
            aidl::android::hardware::automotive::vehicle::VehiclePropConfigs* returnConfigs)
            override;
    ndk::ScopedAStatus getValues(
            const CallbackType& callback,
            const aidl::android::hardware::automotive::vehicle::GetValueRequests& requests)
            override;
    ndk::ScopedAStatus setValues(
            const CallbackType& callback,
            const aidl::android::hardware::automotive::vehicle::SetValueRequests& requests)
            override;
    ndk::ScopedAStatus getPropConfigs(
            const std::vector<int32_t>& props,
            aidl::android::hardware::automotive::vehicle::VehiclePropConfigs* returnConfigs)
            override;
    ndk::ScopedAStatus subscribe(
            const CallbackType& callback,
            const std::vector<aidl::android::hardware::automotive::vehicle::SubscribeOptions>&
                    options,
            int32_t maxSharedMemoryFileCount) override;
    ndk::ScopedAStatus unsubscribe(const CallbackType& callback,
                                   const std::vector<int32_t>& propIds) override;
    ndk::ScopedAStatus returnSharedMemory(const CallbackType& callback,
                                          int64_t sharedMemoryId) override;
    binder_status_t dump(int fd, const char** args, uint32_t numArgs) override;

    IVehicleHardware* getHardware();

  private:
    // friend class for unit testing.
    friend class DefaultVehicleHalTest;

    using GetValuesClient =
            GetSetValuesClient<aidl::android::hardware::automotive::vehicle::GetValueResult,
                               aidl::android::hardware::automotive::vehicle::GetValueResults>;
    using SetValuesClient =
            GetSetValuesClient<aidl::android::hardware::automotive::vehicle::SetValueResult,
                               aidl::android::hardware::automotive::vehicle::SetValueResults>;

    // A thread safe class to maintain an increasing request ID for each subscribe client. This
    // class is safe to pass to async callbacks.
    class SubscribeIdByClient {
      public:
        int64_t getId(const CallbackType& callback);

      private:
        std::mutex mLock;
        std::unordered_map<const AIBinder*, int64_t> mIds GUARDED_BY(mLock);
    };

    // A thread safe class to store all subscribe clients. This class is safe to pass to async
    // callbacks.
    class SubscriptionClients {
      public:
        SubscriptionClients(std::shared_ptr<PendingRequestPool> pool) : mPendingRequestPool(pool) {}

        std::shared_ptr<SubscriptionClient> maybeAddClient(const CallbackType& callback);

        std::shared_ptr<SubscriptionClient> getClient(const CallbackType& callback);

        void removeClient(const AIBinder* clientId);

        size_t countClients();

      private:
        std::mutex mLock;
        std::unordered_map<const AIBinder*, std::shared_ptr<SubscriptionClient>> mClients
                GUARDED_BY(mLock);
        // PendingRequestPool is thread-safe.
        std::shared_ptr<PendingRequestPool> mPendingRequestPool;
    };

    // A wrapper for binder operations to enable stubbing for test.
    class IBinder {
      public:
        virtual ~IBinder() = default;

        virtual binder_status_t linkToDeath(AIBinder* binder, AIBinder_DeathRecipient* recipient,
                                            void* cookie) = 0;

        virtual bool isAlive(const AIBinder* binder) = 0;
    };

    // A real implementation for IBinder.
    class AIBinderImpl final : public IBinder {
      public:
        binder_status_t linkToDeath(AIBinder* binder, AIBinder_DeathRecipient* recipient,
                                    void* cookie) override;

        bool isAlive(const AIBinder* binder) override;
    };

    // OnBinderDiedContext is a type used as a cookie passed deathRecipient. The deathRecipient's
    // onBinderDied function takes only a cookie as input and we have to store all the contexts
    // as the cookie.
    struct OnBinderDiedContext {
        DefaultVehicleHal* vhal;
        const AIBinder* clientId;
    };

    // BinderDiedUnlinkedEvent represents either an onBinderDied or an onBinderUnlinked event.
    struct BinderDiedUnlinkedEvent {
        // true for onBinderDied, false for onBinderUnlinked.
        bool onBinderDied;
        const AIBinder* clientId;
    };

    // The default timeout of get or set value requests is 30s.
    // TODO(b/214605968): define TIMEOUT_IN_NANO in IVehicle and allow getValues/setValues/subscribe
    // to specify custom timeouts.
    static constexpr int64_t TIMEOUT_IN_NANO = 30'000'000'000;
    // heart beat event interval: 3s
    static constexpr int64_t HEART_BEAT_INTERVAL_IN_NANO = 3'000'000'000;
    std::unique_ptr<IVehicleHardware> mVehicleHardware;

    // mConfigsByPropId and mConfigFile are only modified during initialization, so no need to
    // lock guard them.
    std::unordered_map<int32_t, aidl::android::hardware::automotive::vehicle::VehiclePropConfig>
            mConfigsByPropId;
    // Only modified in constructor, so thread-safe.
    std::unique_ptr<ndk::ScopedFileDescriptor> mConfigFile;
    // PendingRequestPool is thread-safe.
    std::shared_ptr<PendingRequestPool> mPendingRequestPool;
    // SubscriptionManager is thread-safe.
    std::shared_ptr<SubscriptionManager> mSubscriptionManager;

    std::mutex mLock;
    std::unordered_map<const AIBinder*, std::unique_ptr<OnBinderDiedContext>> mOnBinderDiedContexts
            GUARDED_BY(mLock);
    std::unordered_map<const AIBinder*, std::shared_ptr<GetValuesClient>> mGetValuesClients
            GUARDED_BY(mLock);
    std::unordered_map<const AIBinder*, std::shared_ptr<SetValuesClient>> mSetValuesClients
            GUARDED_BY(mLock);
    // SubscriptionClients is thread-safe.
    std::shared_ptr<SubscriptionClients> mSubscriptionClients;
    // mBinderImpl is only going to be changed in test.
    std::unique_ptr<IBinder> mBinderImpl;

    // Only initialized once.
    std::shared_ptr<std::function<void()>> mRecurrentAction;
    // RecurrentTimer is thread-safe.
    RecurrentTimer mRecurrentTimer;

    ndk::ScopedAIBinder_DeathRecipient mDeathRecipient;

    // ConcurrentQueue is thread-safe.
    ConcurrentQueue<BinderDiedUnlinkedEvent> mBinderEvents;

    // A thread to handle onBinderDied or onBinderUnlinked event.
    std::thread mOnBinderDiedUnlinkedHandlerThread;

    android::base::Result<void> checkProperty(
            const aidl::android::hardware::automotive::vehicle::VehiclePropValue& propValue);

    android::base::Result<std::vector<int64_t>> checkDuplicateRequests(
            const std::vector<aidl::android::hardware::automotive::vehicle::GetValueRequest>&
                    requests);

    android::base::Result<std::vector<int64_t>> checkDuplicateRequests(
            const std::vector<aidl::android::hardware::automotive::vehicle::SetValueRequest>&
                    requests);

    VhalResult<void> checkSubscribeOptions(
            const std::vector<aidl::android::hardware::automotive::vehicle::SubscribeOptions>&
                    options);

    VhalResult<void> checkReadPermission(
            const aidl::android::hardware::automotive::vehicle::VehiclePropValue& value) const;

    VhalResult<void> checkWritePermission(
            const aidl::android::hardware::automotive::vehicle::VehiclePropValue& value) const;

    android::base::Result<const aidl::android::hardware::automotive::vehicle::VehiclePropConfig*>
    getConfig(int32_t propId) const;

    void onBinderDiedWithContext(const AIBinder* clientId);

    void onBinderUnlinkedWithContext(const AIBinder* clientId);

    // Registers a onBinderDied callback for the client if not already registered.
    // Returns true if the client Binder is alive, false otherwise.
    bool monitorBinderLifeCycleLocked(const AIBinder* clientId) REQUIRES(mLock);

    bool checkDumpPermission();

    // The looping handler function to process all onBinderDied or onBinderUnlinked events in
    // mBinderEvents.
    void onBinderDiedUnlinkedHandler();

    // Gets or creates a {@code T} object for the client to or from {@code clients}.
    template <class T>
    static std::shared_ptr<T> getOrCreateClient(
            std::unordered_map<const AIBinder*, std::shared_ptr<T>>* clients,
            const CallbackType& callback, std::shared_ptr<PendingRequestPool> pendingRequestPool);

    static void onPropertyChangeEvent(
            std::weak_ptr<SubscriptionManager> subscriptionManager,
            const std::vector<aidl::android::hardware::automotive::vehicle::VehiclePropValue>&
                    updatedValues);

    static void checkHealth(IVehicleHardware* hardware,
                            std::weak_ptr<SubscriptionManager> subscriptionManager);

    static void onBinderDied(void* cookie);

    static void onBinderUnlinked(void* cookie);

    // Test-only
    // Set the default timeout for pending requests.
    void setTimeout(int64_t timeoutInNano);

    // Test-only
    void setBinderImpl(std::unique_ptr<IBinder> impl);
};

}  // namespace vehicle
}  // namespace automotive
}  // namespace hardware
}  // namespace android

#endif  // android_hardware_automotive_vehicle_aidl_impl_vhal_include_DefaultVehicleHal_H_