/*
 * Copyright (C) 2019 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_AUTOMOTIVE_EVS_V1_1_HALCAMERA_H
#define ANDROID_AUTOMOTIVE_EVS_V1_1_HALCAMERA_H

#include "stats/CameraUsageStats.h"

#include <deque>
#include <list>
#include <thread>
#include <unordered_map>

#include <android/hardware/automotive/evs/1.1/types.h>
#include <android/hardware/automotive/evs/1.1/IEvsCamera.h>
#include <android/hardware/automotive/evs/1.1/IEvsCameraStream.h>
#include <utils/Mutex.h>
#include <utils/SystemClock.h>

using namespace ::android::hardware::automotive::evs::V1_1;
using ::android::hardware::camera::device::V3_2::Stream;
using ::android::hardware::Return;
using ::android::hardware::hidl_handle;
using ::android::hardware::automotive::evs::V1_0::EvsResult;
using IEvsCamera_1_0 = ::android::hardware::automotive::evs::V1_0::IEvsCamera;
using IEvsCamera_1_1 = ::android::hardware::automotive::evs::V1_1::IEvsCamera;
using BufferDesc_1_0 = ::android::hardware::automotive::evs::V1_0::BufferDesc;
using BufferDesc_1_1 = ::android::hardware::automotive::evs::V1_1::BufferDesc;
using IEvsCameraStream_1_0 = ::android::hardware::automotive::evs::V1_0::IEvsCameraStream;
using IEvsCameraStream_1_1 = ::android::hardware::automotive::evs::V1_1::IEvsCameraStream;

namespace android {
namespace automotive {
namespace evs {
namespace V1_1 {
namespace implementation {


class VirtualCamera;    // From VirtualCamera.h


// This class wraps the actual hardware IEvsCamera objects.  There is a one to many
// relationship between instances of this class and instances of the VirtualCamera class.
// This class implements the IEvsCameraStream interface so that it can receive the video
// stream from the hardware camera and distribute it to the associated VirtualCamera objects.
class HalCamera : public IEvsCameraStream_1_1 {
public:
    HalCamera(sp<IEvsCamera_1_1> hwCamera,
              std::string deviceId = "",
              int32_t recordId = 0,
              Stream cfg = {})
        : mHwCamera(hwCamera),
          mId(deviceId),
          mStreamConfig(cfg),
          mTimeCreatedMs(android::uptimeMillis()),
          mUsageStats(new CameraUsageStats(recordId)) {
        mCurrentRequests = &mFrameRequests[0];
        mNextRequests    = &mFrameRequests[1];
    }

    virtual ~HalCamera();

    // Factory methods for client VirtualCameras
    sp<VirtualCamera>     makeVirtualCamera();
    bool                  ownVirtualCamera(sp<VirtualCamera> virtualCamera);
    void                  disownVirtualCamera(sp<VirtualCamera> virtualCamera);

    // Implementation details
    sp<IEvsCamera_1_0>  getHwCamera()       { return mHwCamera; };
    unsigned            getClientCount()    { return mClients.size(); };
    std::string         getId()             { return mId; }
    Stream&             getStreamConfig()   { return mStreamConfig; }
    bool                changeFramesInFlight(int delta);
    bool                changeFramesInFlight(const hardware::hidl_vec<BufferDesc_1_1>& buffers,
                                             int* delta);
    void                requestNewFrame(sp<VirtualCamera> virtualCamera,
                                        const int64_t timestamp);

    Return<EvsResult>   clientStreamStarting();
    void                clientStreamEnding(const VirtualCamera* client);
    Return<void>        doneWithFrame(const BufferDesc_1_0& buffer);
    Return<void>        doneWithFrame(const BufferDesc_1_1& buffer);
    Return<EvsResult>   setMaster(sp<VirtualCamera> virtualCamera);
    Return<EvsResult>   forceMaster(sp<VirtualCamera> virtualCamera);
    Return<EvsResult>   unsetMaster(sp<VirtualCamera> virtualCamera);
    Return<EvsResult>   setParameter(sp<VirtualCamera> virtualCamera,
                                     CameraParam id, int32_t& value);
    Return<EvsResult>   getParameter(CameraParam id, int32_t& value);

    // Returns a snapshot of collected usage statistics
    CameraUsageStatsRecord getStats() const;

    // Returns active stream configuration
    Stream getStreamConfiguration() const;

    // Returns a string showing the current status
    std::string toString(const char* indent = "") const;

    // Returns a string showing current stream configuration
    static std::string toString(Stream configuration, const char* indent = "");

    // Methods from ::android::hardware::automotive::evs::V1_0::IEvsCameraStream follow.
    Return<void> deliverFrame(const BufferDesc_1_0& buffer) override;

    // Methods from ::android::hardware::automotive::evs::V1_1::IEvsCameraStream follow.
    Return<void> deliverFrame_1_1(const hardware::hidl_vec<BufferDesc_1_1>& buffer) override;
    Return<void> notify(const EvsEventDesc& event) override;

private:
    sp<IEvsCamera_1_1>              mHwCamera;
    std::list<wp<VirtualCamera>>    mClients;   // Weak pointers -> objects destruct if client dies

    enum {
        STOPPED,
        RUNNING,
        STOPPING,
    }                               mStreamState = STOPPED;

    struct FrameRecord {
        uint32_t    frameId;
        uint32_t    refCount;
        FrameRecord(uint32_t id) : frameId(id), refCount(0) {};
    };
    std::vector<FrameRecord>        mFrames;
    wp<VirtualCamera>               mMaster = nullptr;
    std::string                     mId;
    Stream                          mStreamConfig;

    struct FrameRequest {
        wp<VirtualCamera> client = nullptr;
        int64_t           timestamp = -1;
    };

    // synchronization
    mutable std::mutex        mFrameMutex;
    std::deque<FrameRequest>  mFrameRequests[2] GUARDED_BY(mFrameMutex);
    std::deque<FrameRequest>* mCurrentRequests  PT_GUARDED_BY(mFrameMutex);
    std::deque<FrameRequest>* mNextRequests     PT_GUARDED_BY(mFrameMutex);

    // Time this object was created
    int64_t mTimeCreatedMs;

    // usage statistics to collect
    android::sp<CameraUsageStats> mUsageStats;
};

} // namespace implementation
} // namespace V1_1
} // namespace evs
} // namespace automotive
} // namespace android

#endif  // ANDROID_AUTOMOTIVE_EVS_V1_1_HALCAMERA_H