/*
 * Copyright (C) 2011 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 HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H
#define HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H

/*
 * Contains declaration of an abstract class EmulatedCameraDevice that defines
 * functionality expected from an emulated physical camera device:
 *  - Obtaining and setting camera device parameters
 *  - Capturing frames
 *  - Streaming video
 *  - etc.
 */

#include <utils/KeyedVector.h>
#include <utils/String8.h>
#include <utils/threads.h>
#include "Converters.h"
#include "EmulatedCameraCommon.h"

#include <CameraParameters.h>

using ::android::hardware::camera::common::V1_0::helper::CameraParameters;

namespace android {

class EmulatedCamera;

/* Encapsulates an abstract class EmulatedCameraDevice that defines
 * functionality expected from an emulated physical camera device:
 *  - Obtaining and setting camera device parameters
 *  - Capturing frames
 *  - Streaming video
 *  - etc.
 */
class EmulatedCameraDevice {
 public:
  /* Constructs EmulatedCameraDevice instance.
   * Param:
   *  camera_hal - Emulated camera that implements the camera HAL API, and
   *      manages (contains) this object.
   */
  explicit EmulatedCameraDevice(EmulatedCamera* camera_hal);

  /* Destructs EmulatedCameraDevice instance. */
  virtual ~EmulatedCameraDevice();

  /***************************************************************************
   * Emulated camera device abstract interface
   **************************************************************************/

 public:
  /* Connects to the camera device.
   * This method must be called on an initialized instance of this class.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t connectDevice() = 0;

  /* Disconnects from the camera device.
   * Return:
   *  NO_ERROR on success, or an appropriate error status. If this method is
   *  called for already disconnected, or uninitialized instance of this class,
   *  a successful status must be returned from this method. If this method is
   *  called for an instance that is in the "started" state, this method must
   *  return a failure.
   */
  virtual status_t disconnectDevice() = 0;

  /* Starts the camera device.
   * This method tells the camera device to start capturing frames of the given
   * dimensions for the given pixel format. Note that this method doesn't start
   * the delivery of the captured frames to the emulated camera. Call
   * startDeliveringFrames method to start delivering frames. This method must
   * be called on a connected instance of this class. If it is called on a
   * disconnected instance, this method must return a failure.
   * Param:
   *  width, height - Frame dimensions to use when capturing video frames.
   *  pix_fmt - Pixel format to use when capturing video frames.
   *  fps - Target rate of frames per second.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t startDevice(int width, int height, uint32_t pix_fmt,
                               int fps) = 0;

  /* Stops the camera device.
   * This method tells the camera device to stop capturing frames. Note that
   * this method doesn't stop delivering frames to the emulated camera. Always
   * call stopDeliveringFrames prior to calling this method.
   * Return:
   *  NO_ERROR on success, or an appropriate error status. If this method is
   *  called for an object that is not capturing frames, or is disconnected,
   *  or is uninitialized, a successful status must be returned from this
   *  method.
   */
  virtual status_t stopDevice() = 0;

  /***************************************************************************
   * Emulated camera device public API
   **************************************************************************/

 public:
  /* Initializes EmulatedCameraDevice instance.
   * Derived classes should override this method in order to cache static
   * properties of the physical device (list of supported pixel formats, frame
   * sizes, etc.) If this method is called on an already initialized instance,
   * it must return a successful status.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t Initialize();

  /* Initializes the white balance modes parameters.
   * The parameters are passed by each individual derived camera API to
   * represent that different camera manufacturers may have different
   * preferences on the white balance parameters. Green channel in the RGB
   * color space is fixed to keep the luminance to be reasonably constant.
   *
   * Param:
   * mode the text describing the current white balance mode
   * r_scale the scale factor for the R channel in RGB space
   * b_scale the scale factor for the B channel in RGB space.
   */
  void initializeWhiteBalanceModes(const char* mode, const float r_scale,
                                   const float b_scale);

  /* Starts delivering frames captured from the camera device.
   * This method will start the worker thread that would be pulling frames from
   * the camera device, and will deliver the pulled frames back to the emulated
   * camera via onNextFrameAvailable callback. This method must be called on a
   * connected instance of this class with a started camera device. If it is
   * called on a disconnected instance, or camera device has not been started,
   * this method must return a failure.
   * Param:
   *  one_burst - Controls how many frames should be delivered. If this
   *      parameter is 'true', only one captured frame will be delivered to the
   *      emulated camera. If this parameter is 'false', frames will keep
   *      coming until stopDeliveringFrames method is called. Typically, this
   *      parameter is set to 'true' only in order to obtain a single frame
   *      that will be used as a "picture" in takePicture method of the
   *      emulated camera.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t startDeliveringFrames(bool one_burst);

  /* Stops delivering frames captured from the camera device.
   * This method will stop the worker thread started by startDeliveringFrames.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t stopDeliveringFrames();

  /* Sets the exposure compensation for the camera device.
   */
  void setExposureCompensation(const float ev);

  /* Sets the white balance mode for the device.
   */
  void setWhiteBalanceMode(const char* mode);

  /* Initiates focus operation.
   */
  virtual void startAutoFocus();

  /* Gets current framebuffer, converted into preview frame format.
   * This method must be called on a connected instance of this class with a
   * started camera device. If it is called on a disconnected instance, or
   * camera device has not been started, this method must return a failure.
   * Note that this method should be called only after at least one frame has
   * been captured and delivered. Otherwise it will return garbage in the
   * preview frame buffer. Typically, this method shuld be called from
   * onNextFrameAvailable callback.
   * Param:
   *  buffer - Buffer, large enough to contain the entire preview frame.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t getCurrentPreviewFrame(void* buffer);

  /* Gets width of the frame obtained from the physical device.
   * Return:
   *  Width of the frame obtained from the physical device. Note that value
   *  returned from this method is valid only in case if camera device has been
   *  started.
   */
  inline int getFrameWidth() const {
    ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
    return mFrameWidth;
  }

  /* Gets height of the frame obtained from the physical device.
   * Return:
   *  Height of the frame obtained from the physical device. Note that value
   *  returned from this method is valid only in case if camera device has been
   *  started.
   */
  inline int getFrameHeight() const {
    ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
    return mFrameHeight;
  }

  /* Gets byte size of the current frame buffer.
   * Return:
   *  Byte size of the frame buffer. Note that value returned from this method
   *  is valid only in case if camera device has been started.
   */
  inline size_t getFrameBufferSize() const {
    ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
    return mFrameBufferSize;
  }

  /* Gets number of pixels in the current frame buffer.
   * Return:
   *  Number of pixels in the frame buffer. Note that value returned from this
   *  method is valid only in case if camera device has been started.
   */
  inline int getPixelNum() const {
    ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
    return mTotalPixels;
  }

  /* Gets pixel format of the frame that camera device streams to this class.
   * Throughout camera framework, there are three different forms of pixel
   * format representation:
   *  - Original format, as reported by the actual camera device. Values for
   *    this format are declared in bionic/libc/kernel/common/linux/videodev2.h
   *  - String representation as defined in CameraParameters::PIXEL_FORMAT_XXX
   *    strings in frameworks/base/include/camera/CameraParameters.h
   *  - HAL_PIXEL_FORMAT_XXX format, as defined in
   * system/core/include/system/graphics.h Since emulated camera device gets its
   * data from the actual device, it gets pixel format in the original form. And
   * that's the pixel format representation that will be returned from this
   * method. HAL components will need to translate value returned from this
   * method to the appropriate form. This method must be called only on started
   * instance of this class, since it's applicable only when camera device is
   * ready to stream frames. Param: pix_fmt - Upon success contains the original
   * pixel format. Return: Current framebuffer's pixel format. Note that value
   * returned from this method is valid only in case if camera device has been
   * started.
   */
  inline uint32_t getOriginalPixelFormat() const {
    ALOGE_IF(!isStarted(), "%s: Device is not started", __FUNCTION__);
    return mPixelFormat;
  }

  /* Gets image metadata (from HAL).
   * Return:
   *  Filled in ImageMetadata structure (in/out parameter).
   */
  const CameraParameters* getCameraParameters();

  /*
   * State checkers.
   */

  inline bool isInitialized() const {
    /* Instance is initialized when the worker thread has been successfuly
     * created (but not necessarily started). */
    return mWorkerThread.get() != NULL && mState != ECDS_CONSTRUCTED;
  }
  inline bool isConnected() const {
    /* Instance is connected when its status is either"connected", or
     * "started". */
    return mState == ECDS_CONNECTED || mState == ECDS_STARTED;
  }
  inline bool isStarted() const { return mState == ECDS_STARTED; }

  /****************************************************************************
   * Emulated camera device private API
   ***************************************************************************/
 protected:
  /* Performs common validation and calculation of startDevice parameters.
   * Param:
   *  width, height, pix_fmt, fps - Parameters passed to startDevice method.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t commonStartDevice(int width, int height, uint32_t pix_fmt,
                                     int fps);

  /* Performs common cleanup on stopDevice.
   * This method will undo what commonStartDevice had done.
   */
  virtual void commonStopDevice();

  /** Computes a luminance value after taking the exposure compensation.
   * value into account.
   *
   * Param:
   * inputY - The input luminance value.
   * Return:
   * The luminance value after adjusting the exposure compensation.
   */
  inline uint8_t changeExposure(const uint8_t& inputY) const {
    return static_cast<uint8_t>(
        clamp(static_cast<float>(inputY) * mExposureCompensation));
  }

  /** Simulates focusing and reports completion to the client.
   */
  void simulateAutoFocus();

  /** Computes the pixel value in YUV space after adjusting to the current
   * white balance mode.
   */
  void changeWhiteBalance(uint8_t& y, uint8_t& u, uint8_t& v) const;

  /****************************************************************************
   * Worker thread management.
   * Typicaly when emulated camera device starts capturing frames from the
   * actual device, it does that in a worker thread created in StartCapturing,
   * and terminated in StopCapturing. Since this is such a typical scenario,
   * it makes sence to encapsulate worker thread management in the base class
   * for all emulated camera devices.
   ***************************************************************************/

 protected:
  /* Starts the worker thread.
   * Typically, worker thread is started from startDeliveringFrames method of
   * this class.
   * Param:
   *  one_burst - Controls how many times thread loop should run. If this
   *      parameter is 'true', thread routine will run only once If this
   *      parameter is 'false', thread routine will run until stopWorkerThread
   *      method is called. See startDeliveringFrames for more info.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t startWorkerThread(bool one_burst);

  /* Stops the worker thread.
   * Note that this method will always wait for the worker thread to terminate.
   * Typically, worker thread is started from stopDeliveringFrames method of
   * this class.
   * Return:
   *  NO_ERROR on success, or an appropriate error status.
   */
  virtual status_t stopWorkerThread();

  /* Implementation of the worker thread routine.
   * In the default implementation of the worker thread routine we simply
   * return 'false' forcing the thread loop to exit, and the thread to
   * terminate. Derived class should override that method to provide there the
   * actual frame delivery.
   * Return:
   *  true To continue thread loop (this method will be called again), or false
   *  to exit the thread loop and to terminate the thread.
   */
  virtual bool inWorkerThread();

  /* Encapsulates a worker thread used by the emulated camera device.
   */
  friend class WorkerThread;
  class WorkerThread : public Thread {
    /****************************************************************************
     * Public API
     ***************************************************************************/

   public:
    inline explicit WorkerThread(EmulatedCameraDevice* camera_dev)
        : Thread(true),  // Callbacks may involve Java calls.
          mCameraDevice(camera_dev),
          mThreadControl(-1),
          mControlFD(-1) {}

    inline ~WorkerThread() {
      ALOGW_IF(mThreadControl >= 0 || mControlFD >= 0,
               "%s: Control FDs are opened in the destructor", __FUNCTION__);
      if (mThreadControl >= 0) {
        close(mThreadControl);
      }
      if (mControlFD >= 0) {
        close(mControlFD);
      }
    }

    /* Starts the thread
     * Param:
     *  one_burst - Controls how many times thread loop should run. If
     *      this parameter is 'true', thread routine will run only once
     *      If this parameter is 'false', thread routine will run until
     *      stopThread method is called. See startWorkerThread for more
     *      info.
     * Return:
     *  NO_ERROR on success, or an appropriate error status.
     */
    inline status_t startThread(bool one_burst) {
      mOneBurst = one_burst;
      return run("Camera_startThread", ANDROID_PRIORITY_URGENT_DISPLAY, 0);
    }

    /* Overriden base class method.
     * It is overriden in order to provide one-time initialization just
     * prior to starting the thread routine.
     */
    status_t readyToRun();

    /* Stops the thread. */
    status_t stopThread();

    /* Values returned from the Select method of this class. */
    enum SelectRes {
      /* A timeout has occurred. */
      TIMEOUT,
      /* Data are available for read on the provided FD. */
      READY,
      /* Thread exit request has been received. */
      EXIT_THREAD,
      /* An error has occurred. */
      ERROR
    };

    /* Select on an FD event, keeping in mind thread exit message.
     * Param:
     *  fd - File descriptor on which to wait for an event. This
     *      parameter may be negative. If it is negative this method will
     *      only wait on a control message to the thread.
     *  timeout - Timeout in microseconds. 0 indicates no timeout (wait
     *      forever).
     * Return:
     *  See SelectRes enum comments.
     */
    SelectRes Select(int fd, int timeout);

    /****************************************************************************
     * Private API
     ***************************************************************************/

   private:
    /* Implements abstract method of the base Thread class. */
    bool threadLoop() {
      /* Simply dispatch the call to the containing camera device. */
      if (mCameraDevice->inWorkerThread()) {
        /* Respect "one burst" parameter (see startThread). */
        return !mOneBurst;
      } else {
        return false;
      }
    }

    /* Containing camera device object. */
    EmulatedCameraDevice* mCameraDevice;

    /* FD that is used to send control messages into the thread. */
    int mThreadControl;

    /* FD that thread uses to receive control messages. */
    int mControlFD;

    /* Controls number of times the thread loop runs.
     * See startThread for more information. */
    bool mOneBurst;

    /* Enumerates control messages that can be sent into the thread. */
    enum ControlMessage {
      /* Stop the thread. */
      THREAD_STOP
    };

    Condition mSetup;
  };

  /* Worker thread accessor. */
  inline WorkerThread* getWorkerThread() const { return mWorkerThread.get(); }

  /****************************************************************************
   * Data members
   ***************************************************************************/

 protected:
  /* Locks this instance for parameters, state, etc. change. */
  Mutex mObjectLock;

  /* Worker thread that is used in frame capturing. */
  sp<WorkerThread> mWorkerThread;

  /* Timestamp of the current frame. */
  nsecs_t mCurFrameTimestamp;

  /* Emulated camera object containing this instance. */
  EmulatedCamera* mCameraHAL;

  /* Framebuffer containing the current frame. */
  uint8_t* mCurrentFrame;

  /*
   * Framebuffer properties.
   */

  /* Byte size of the framebuffer. */
  size_t mFrameBufferSize;

  /* Original pixel format (one of the V4L2_PIX_FMT_XXX values, as defined in
   * bionic/libc/kernel/common/linux/videodev2.h */
  uint32_t mPixelFormat;

  /* Frame width */
  int mFrameWidth;

  /* Frame height */
  int mFrameHeight;

  /* Total number of pixels */
  int mTotalPixels;

  /* Requested FPS rate */
  int mTargetFps;

  /* Exposure compensation value */
  float mExposureCompensation;

  float* mWhiteBalanceScale;

  bool mIsFocusing;

  DefaultKeyedVector<String8, float*> mSupportedWhiteBalanceScale;

  /* Defines possible states of the emulated camera device object.
   */
  enum EmulatedCameraDeviceState {
    /* Object has been constructed. */
    ECDS_CONSTRUCTED,
    /* Object has been initialized. */
    ECDS_INITIALIZED,
    /* Object has been connected to the physical device. */
    ECDS_CONNECTED,
    /* Camera device has been started. */
    ECDS_STARTED,
  };

  /* Object state. */
  EmulatedCameraDeviceState mState;
};

}; /* namespace android */

#endif /* HW_EMULATOR_CAMERA_EMULATED_CAMERA_DEVICE_H */