/*----------------------------------------------------------------------------*/
/* Copyright (c) 2017 FIRST. All Rights Reserved.                             */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#include "HAL/DriverStation.h"

#ifdef __APPLE__
#include <pthread.h>
#endif

#include <condition_variable>
#include <cstdio>
#include <cstdlib>
#include <mutex>
#include <string>

#include "MockData/DriverStationDataInternal.h"
#include "MockData/MockHooks.h"

static std::mutex msgMutex;
static std::condition_variable newDSDataAvailableCond;
static std::mutex newDSDataAvailableMutex;
static int newDSDataAvailableCounter{0};

using namespace hal;

extern "C" {
int32_t HAL_SetErrorData(const char* errors, int32_t errorsLength,
                         int32_t waitMs) {
  return 0;
}

int32_t HAL_SendError(HAL_Bool isError, int32_t errorCode, HAL_Bool isLVCode,
                      const char* details, const char* location,
                      const char* callStack, HAL_Bool printMsg) {
  // Avoid flooding console by keeping track of previous 5 error
  // messages and only printing again if they're longer than 1 second old.
  static constexpr int KEEP_MSGS = 5;
  std::lock_guard<std::mutex> lock(msgMutex);
  static std::string prevMsg[KEEP_MSGS];
  static std::chrono::time_point<std::chrono::steady_clock>
      prevMsgTime[KEEP_MSGS];
  static bool initialized = false;
  if (!initialized) {
    for (int i = 0; i < KEEP_MSGS; i++) {
      prevMsgTime[i] =
          std::chrono::steady_clock::now() - std::chrono::seconds(2);
    }
    initialized = true;
  }

  auto curTime = std::chrono::steady_clock::now();
  int i;
  for (i = 0; i < KEEP_MSGS; ++i) {
    if (prevMsg[i] == details) break;
  }
  int retval = 0;
  if (i == KEEP_MSGS || (curTime - prevMsgTime[i]) >= std::chrono::seconds(1)) {
    printMsg = true;
    if (printMsg) {
      if (location && location[0] != '\0') {
        std::fprintf(stderr, "%s at %s: ", isError ? "Error" : "Warning",
                     location);
      }
      std::fprintf(stderr, "%s\n", details);
      if (callStack && callStack[0] != '\0') {
        std::fprintf(stderr, "%s\n", callStack);
      }
    }
    if (i == KEEP_MSGS) {
      // replace the oldest one
      i = 0;
      auto first = prevMsgTime[0];
      for (int j = 1; j < KEEP_MSGS; ++j) {
        if (prevMsgTime[j] < first) {
          first = prevMsgTime[j];
          i = j;
        }
      }
      prevMsg[i] = details;
    }
    prevMsgTime[i] = curTime;
  }
  return retval;
}

int32_t HAL_GetControlWord(HAL_ControlWord* controlWord) {
  controlWord->enabled = SimDriverStationData.GetEnabled();
  controlWord->autonomous = SimDriverStationData.GetAutonomous();
  controlWord->test = SimDriverStationData.GetTest();
  controlWord->eStop = SimDriverStationData.GetEStop();
  controlWord->fmsAttached = SimDriverStationData.GetFmsAttached();
  controlWord->dsAttached = SimDriverStationData.GetDsAttached();
  return 0;
}

HAL_AllianceStationID HAL_GetAllianceStation(int32_t* status) {
  *status = 0;
  return SimDriverStationData.GetAllianceStationId();
}

int32_t HAL_GetJoystickAxes(int32_t joystickNum, HAL_JoystickAxes* axes) {
  return 0;
}

int32_t HAL_GetJoystickPOVs(int32_t joystickNum, HAL_JoystickPOVs* povs) {
  return 0;
}

int32_t HAL_GetJoystickButtons(int32_t joystickNum,
                               HAL_JoystickButtons* buttons) {
  return 0;
}
/**
 * Retrieve the Joystick Descriptor for particular slot
 * @param desc [out] descriptor (data transfer object) to fill in.  desc is
 * filled in regardless of success. In other words, if descriptor is not
 * available, desc is filled in with default values matching the init-values in
 * Java and C++ Driverstation for when caller requests a too-large joystick
 * index.
 *
 * @return error code reported from Network Comm back-end.  Zero is good,
 * nonzero is bad.
 */
int32_t HAL_GetJoystickDescriptor(int32_t joystickNum,
                                  HAL_JoystickDescriptor* desc) {
  return 0;
}

HAL_Bool HAL_GetJoystickIsXbox(int32_t joystickNum) { return false; }

int32_t HAL_GetJoystickType(int32_t joystickNum) { return 0; }

char* HAL_GetJoystickName(int32_t joystickNum) {
  char* name = static_cast<char*>(std::malloc(1));
  name[0] = '\0';
  return name;
}

void HAL_FreeJoystickName(char* name) { std::free(name); }

int32_t HAL_GetJoystickAxisType(int32_t joystickNum, int32_t axis) { return 0; }

int32_t HAL_SetJoystickOutputs(int32_t joystickNum, int64_t outputs,
                               int32_t leftRumble, int32_t rightRumble) {
  return 0;
}

double HAL_GetMatchTime(int32_t* status) {
  return SimDriverStationData.GetMatchTime();
}

void HAL_ObserveUserProgramStarting(void) { HALSIM_SetProgramStarted(); }

void HAL_ObserveUserProgramDisabled(void) {
  // TODO
}

void HAL_ObserveUserProgramAutonomous(void) {
  // TODO
}

void HAL_ObserveUserProgramTeleop(void) {
  // TODO
}

void HAL_ObserveUserProgramTest(void) {
  // TODO
}

#ifdef __APPLE__
static pthread_key_t lastCountKey;
static pthread_once_t lastCountKeyOnce = PTHREAD_ONCE_INIT;

static void InitLastCountKey() { pthread_key_create(&lastCountKey, std::free); }
#endif

bool HAL_IsNewControlData(void) {
#ifdef __APPLE__
  pthread_once(&lastCountKeyOnce, InitLastCountKey);
  int* lastCountPtr = static_cast<int*>(pthread_getspecific(lastCountKey));
  if (!lastCountPtr) {
    lastCountPtr = static_cast<int*>(std::malloc(sizeof(int)));
    *lastCountPtr = -1;
    pthread_setspecific(lastCountKey, lastCountPtr);
  }
  int& lastCount = *lastCountPtr;
#else
  thread_local int lastCount{-1};
#endif
  // There is a rollover error condition here. At Packet# = n * (uintmax), this
  // will return false when instead it should return true. However, this at a
  // 20ms rate occurs once every 2.7 years of DS connected runtime, so not
  // worth the cycles to check.
  int currentCount = 0;
  {
    std::unique_lock<std::mutex> lock(newDSDataAvailableMutex);
    currentCount = newDSDataAvailableCounter;
  }
  if (lastCount == currentCount) return false;
  lastCount = currentCount;
  return true;
}

/**
 * Waits for the newest DS packet to arrive. Note that this is a blocking call.
 */
void HAL_WaitForDSData(void) { HAL_WaitForDSDataTimeout(0); }

/**
 * Waits for the newest DS packet to arrive. If timeout is <= 0, this will wait
 * forever. Otherwise, it will wait until either a new packet, or the timeout
 * time has passed. Returns true on new data, false on timeout.
 */
HAL_Bool HAL_WaitForDSDataTimeout(double timeout) {
  auto timeoutTime =
      std::chrono::steady_clock::now() + std::chrono::duration<double>(timeout);

  std::unique_lock<std::mutex> lock(newDSDataAvailableMutex);
  int currentCount = newDSDataAvailableCounter;
  while (newDSDataAvailableCounter == currentCount) {
    if (timeout > 0) {
      auto timedOut = newDSDataAvailableCond.wait_until(lock, timeoutTime);
      if (timedOut == std::cv_status::timeout) {
        return false;
      }
    } else {
      newDSDataAvailableCond.wait(lock);
    }
  }
  return true;
}

// Constant number to be used for our occur handle
constexpr int32_t refNumber = 42;

static int32_t newDataOccur(uint32_t refNum) {
  // Since we could get other values, require our specific handle
  // to signal our threads
  if (refNum != refNumber) return 0;
  std::lock_guard<std::mutex> lock(newDSDataAvailableMutex);
  // Nofify all threads
  newDSDataAvailableCounter++;
  newDSDataAvailableCond.notify_all();
  return 0;
}

/*
 * Call this to initialize the driver station communication. This will properly
 * handle multiple calls. However note that this CANNOT be called from a library
 * that interfaces with LabVIEW.
 */
void HAL_InitializeDriverStation(void) {
  static std::atomic_bool initialized{false};
  static std::mutex initializeMutex;
  // Initial check, as if it's true initialization has finished
  if (initialized) return;

  std::lock_guard<std::mutex> lock(initializeMutex);
  // Second check in case another thread was waiting
  if (initialized) return;

  SimDriverStationData.ResetData();

  initialized = true;
}

/*
 * Releases the DS Mutex to allow proper shutdown of any threads that are
 * waiting on it.
 */
void HAL_ReleaseDSMutex(void) { newDataOccur(refNumber); }

}  // extern "C"