/*
 * utility_asynchuartlogger.cpp
 *
 *  Created on: Mar 20, 2021
 *      Author: erki
 */

#include "utility_asyncaurtlogger.hpp"

#include <cstdlib>
#include <cstdarg>
#include <cassert>

#include "utility_atomicscopeguard.hpp"

namespace Utility
{

AsyncUARTLogger* AsyncUARTLogger::_this = nullptr;

AsyncUARTLogger::AsyncUARTLogger(UART_HandleTypeDef* huart)
  : _huart(huart)
{
  assert(!_this);

  _this = this;
  _huart->TxCpltCallback = &AsyncUARTLogger::_txCompleteCallback;
}

void AsyncUARTLogger::log(const char* format, ...)
{
  {
    AtomicScopeGuard s;

    if (_buffer_queue.size() == _buffer_queue.max_size())
      return;
  }

  std::va_list args;
  va_start(args, format);

  auto tail = _buffer_queue.end();
  std::array<char, 255>& buffer = tail->buffer;

  tail->length = vsnprintf(buffer.data(), buffer.size(), format, args);

  {
    AtomicScopeGuard s;
    _buffer_queue.increment_tail();

    if (!_in_flight)
      _sendNextLog();
  }
}

void AsyncUARTLogger::_txCompleteCallback(UART_HandleTypeDef*)
{
  if (!AsyncUARTLogger::_this->_buffer_queue.empty())
    AsyncUARTLogger::_this->_sendNextLog();
  else
    AsyncUARTLogger::_this->_in_flight = false;
}

void AsyncUARTLogger::_sendNextLog()
{
  _in_flight = true;

  _Data& head = _buffer_queue.front();
  HAL_UART_Transmit_DMA(_huart, reinterpret_cast<uint8_t*>(head.buffer.data()), head.length);
  _buffer_queue.pop_front();
}

}