#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stm32f1xx_hal.h>

UART_HandleTypeDef huart2;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);

int main(void) {
  const char * hello_world = "Hello STM32\r\n";

  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_USART2_UART_Init();

  HAL_UART_Transmit(&huart2, (uint8_t *)hello_world, strlen(hello_world), HAL_MAX_DELAY);

  printf("Characters: %c %c\n", 'a', 65);
  printf("Decimals: %d %ld\n", 1977, 650000L);
  printf("Preceding with blanks: %10d\n", 1977);
  printf("Preceding with zeros: %010d\n", 1977);
  printf("Some different radices: %d %x %o %#x %#o\n", 100, 100, 100, 100, 100);
  printf("floats: %4.2f %+.0e %E\n", 3.1416, 3.1416, 3.1416);
  printf("Width trick: %*d\n", 5, 10);
  printf("%s\n", "A string");

  while (1);

  return 0;
}

void SystemClock_Config(void) {
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  HAL_RCC_OscConfig(&RCC_OscInitStruct);
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2);
}

void SysTick_Handler(void) {
  HAL_IncTick();
}

static void MX_USART2_UART_Init(void) {
  __HAL_RCC_USART2_CLK_ENABLE();
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  HAL_UART_Init(&huart2);
}
void MX_GPIO_Init(void) {
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  GPIO_InitStruct.Pin = GPIO_PIN_2 | GPIO_PIN_3;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

#define STDOUT_FILENO   1
#define STDERR_FILENO   2

int _write(int file, char *ptr, int len)
{
  switch (file)
  {
    case STDOUT_FILENO: /*stdout*/
      HAL_UART_Transmit(&huart2, ptr, len, HAL_MAX_DELAY);
      // Send the string somewhere
      break;
    case STDERR_FILENO: /* stderr */
      HAL_UART_Transmit(&huart2, ptr, len, HAL_MAX_DELAY);
      // Send the string somewhere
      break;
    default:
      return -1;
  }
  return len;
}