/*
 * 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 ANDROID_POWERHALWRAPPER_H
#define ANDROID_POWERHALWRAPPER_H

#include <android-base/thread_annotations.h>
#include <android/hardware/power/1.1/IPower.h>
#include <android/hardware/power/Boost.h>
#include <android/hardware/power/IPower.h>
#include <android/hardware/power/IPowerHintSession.h>
#include <android/hardware/power/Mode.h>

namespace android {

namespace power {

// State of Power HAL support for individual apis.
enum class HalSupport {
    UNKNOWN = 0,
    ON = 1,
    OFF = 2,
};

// Result of a call to the Power HAL wrapper, holding data if successful.
template <typename T>
class HalResult {
public:
    static HalResult<T> ok(T value) { return HalResult(value); }
    static HalResult<T> failed(std::string msg) {
        return HalResult(std::move(msg), /* unsupported= */ false);
    }
    static HalResult<T> unsupported() { return HalResult("", /* unsupported= */ true); }

    static HalResult<T> fromStatus(binder::Status status, T data) {
        if (status.exceptionCode() == binder::Status::EX_UNSUPPORTED_OPERATION) {
            return HalResult<T>::unsupported();
        }
        if (status.isOk()) {
            return HalResult<T>::ok(data);
        }
        return HalResult<T>::failed(std::string(status.toString8().c_str()));
    }
    static HalResult<T> fromStatus(hardware::power::V1_0::Status status, T data);

    template <typename R>
    static HalResult<T> fromReturn(hardware::Return<R>& ret, T data);

    template <typename R>
    static HalResult<T> fromReturn(hardware::Return<R>& ret, hardware::power::V1_0::Status status,
                                   T data);

    // This will throw std::bad_optional_access if this result is not ok.
    const T& value() const { return mValue.value(); }
    bool isOk() const { return !mUnsupported && mValue.has_value(); }
    bool isFailed() const { return !mUnsupported && !mValue.has_value(); }
    bool isUnsupported() const { return mUnsupported; }
    const char* errorMessage() const { return mErrorMessage.c_str(); }

private:
    std::optional<T> mValue;
    std::string mErrorMessage;
    bool mUnsupported;

    explicit HalResult(T value)
          : mValue(std::make_optional(value)), mErrorMessage(), mUnsupported(false) {}
    explicit HalResult(std::string errorMessage, bool unsupported)
          : mValue(), mErrorMessage(std::move(errorMessage)), mUnsupported(unsupported) {}
};

// Empty result of a call to the Power HAL wrapper.
template <>
class HalResult<void> {
public:
    static HalResult<void> ok() { return HalResult(); }
    static HalResult<void> failed(std::string msg) { return HalResult(std::move(msg)); }
    static HalResult<void> unsupported() { return HalResult(/* unsupported= */ true); }

    static HalResult<void> fromStatus(status_t status);
    static HalResult<void> fromStatus(binder::Status status);
    static HalResult<void> fromStatus(hardware::power::V1_0::Status status);

    template <typename R>
    static HalResult<void> fromReturn(hardware::Return<R>& ret);

    bool isOk() const { return !mUnsupported && !mFailed; }
    bool isFailed() const { return !mUnsupported && mFailed; }
    bool isUnsupported() const { return mUnsupported; }
    const char* errorMessage() const { return mErrorMessage.c_str(); }

private:
    std::string mErrorMessage;
    bool mFailed;
    bool mUnsupported;

    explicit HalResult(bool unsupported = false)
          : mErrorMessage(), mFailed(false), mUnsupported(unsupported) {}
    explicit HalResult(std::string errorMessage)
          : mErrorMessage(std::move(errorMessage)), mFailed(true), mUnsupported(false) {}
};

// Wrapper for Power HAL handlers.
class HalWrapper {
public:
    virtual ~HalWrapper() = default;

    virtual HalResult<void> setBoost(hardware::power::Boost boost, int32_t durationMs) = 0;
    virtual HalResult<void> setMode(hardware::power::Mode mode, bool enabled) = 0;
    virtual HalResult<sp<hardware::power::IPowerHintSession>> createHintSession(
            int32_t tgid, int32_t uid, const std::vector<int32_t>& threadIds,
            int64_t durationNanos) = 0;
    virtual HalResult<int64_t> getHintSessionPreferredRate() = 0;
};

// Empty Power HAL wrapper that ignores all api calls.
class EmptyHalWrapper : public HalWrapper {
public:
    EmptyHalWrapper() = default;
    ~EmptyHalWrapper() = default;

    virtual HalResult<void> setBoost(hardware::power::Boost boost, int32_t durationMs) override;
    virtual HalResult<void> setMode(hardware::power::Mode mode, bool enabled) override;
    virtual HalResult<sp<hardware::power::IPowerHintSession>> createHintSession(
            int32_t tgid, int32_t uid, const std::vector<int32_t>& threadIds,
            int64_t durationNanos) override;
    virtual HalResult<int64_t> getHintSessionPreferredRate() override;
};

// Wrapper for the HIDL Power HAL v1.0.
class HidlHalWrapperV1_0 : public HalWrapper {
public:
    explicit HidlHalWrapperV1_0(sp<hardware::power::V1_0::IPower> Hal)
          : mHandleV1_0(std::move(Hal)) {}
    virtual ~HidlHalWrapperV1_0() = default;

    virtual HalResult<void> setBoost(hardware::power::Boost boost, int32_t durationMs) override;
    virtual HalResult<void> setMode(hardware::power::Mode mode, bool enabled) override;
    virtual HalResult<sp<hardware::power::IPowerHintSession>> createHintSession(
            int32_t tgid, int32_t uid, const std::vector<int32_t>& threadIds,
            int64_t durationNanos) override;
    virtual HalResult<int64_t> getHintSessionPreferredRate() override;

protected:
    virtual HalResult<void> sendPowerHint(hardware::power::V1_0::PowerHint hintId, uint32_t data);

private:
    sp<hardware::power::V1_0::IPower> mHandleV1_0;
    HalResult<void> setInteractive(bool enabled);
    HalResult<void> setFeature(hardware::power::V1_0::Feature feature, bool enabled);
};

// Wrapper for the HIDL Power HAL v1.1.
class HidlHalWrapperV1_1 : public HidlHalWrapperV1_0 {
public:
    HidlHalWrapperV1_1(sp<hardware::power::V1_0::IPower> handleV1_0,
                       sp<hardware::power::V1_1::IPower> handleV1_1)
          : HidlHalWrapperV1_0(std::move(handleV1_0)), mHandleV1_1(std::move(handleV1_1)) {}
    virtual ~HidlHalWrapperV1_1() = default;

protected:
    virtual HalResult<void> sendPowerHint(hardware::power::V1_0::PowerHint hintId,
                                          uint32_t data) override;

private:
    sp<hardware::power::V1_1::IPower> mHandleV1_1;
};

// Wrapper for the AIDL Power HAL.
class AidlHalWrapper : public HalWrapper {
public:
    explicit AidlHalWrapper(sp<hardware::power::IPower> handle) : mHandle(std::move(handle)) {}
    virtual ~AidlHalWrapper() = default;

    virtual HalResult<void> setBoost(hardware::power::Boost boost, int32_t durationMs) override;
    virtual HalResult<void> setMode(hardware::power::Mode mode, bool enabled) override;
    virtual HalResult<sp<hardware::power::IPowerHintSession>> createHintSession(
            int32_t tgid, int32_t uid, const std::vector<int32_t>& threadIds,
            int64_t durationNanos) override;
    virtual HalResult<int64_t> getHintSessionPreferredRate() override;

private:
    // Control access to the boost and mode supported arrays.
    std::mutex mBoostMutex;
    std::mutex mModeMutex;
    sp<hardware::power::IPower> mHandle;
    // Android framework only sends boost upto DISPLAY_UPDATE_IMMINENT.
    // Need to increase the array size if more boost supported.
    std::array<std::atomic<HalSupport>,
               static_cast<int32_t>(hardware::power::Boost::DISPLAY_UPDATE_IMMINENT) + 1>
            mBoostSupportedArray GUARDED_BY(mBoostMutex) = {HalSupport::UNKNOWN};
    // Android framework only sends mode upto DISPLAY_INACTIVE.
    // Need to increase the array if more mode supported.
    std::array<std::atomic<HalSupport>,
               static_cast<int32_t>(hardware::power::Mode::DISPLAY_INACTIVE) + 1>
            mModeSupportedArray GUARDED_BY(mModeMutex) = {HalSupport::UNKNOWN};
};

}; // namespace power

}; // namespace android

#endif // ANDROID_POWERHALWRAPPER_H