#include "stm32c0xx_hal.h"
#include <stdio.h>

UART_HandleTypeDef huart1;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART1_UART_Init(void);

int __io_putchar(int ch)
{
  HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, HAL_MAX_DELAY);
  return ch;
}

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_USART1_UART_Init();

  printf("Experiment 9 Started (Polling Mode)...\n");

  while (1)
  {
    // Read button state
    if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0) == GPIO_PIN_RESET)
    {
      HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_5);
      printf("Button Pressed! LED Toggled\n");

      HAL_Delay(300); // Debounce
    }
  }
}

//////////////////////////////////////////////////////////
// GPIO INIT
//////////////////////////////////////////////////////////
static void MX_GPIO_Init(void)
{
  __HAL_RCC_GPIOA_CLK_ENABLE();

  GPIO_InitTypeDef GPIO_InitStruct = {0};

  // LED (PA5)
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  // Button (PA0)
  GPIO_InitStruct.Pin = GPIO_PIN_0;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

//////////////////////////////////////////////////////////
// UART INIT
//////////////////////////////////////////////////////////
static void MX_USART1_UART_Init(void)
{
  __HAL_RCC_USART1_CLK_ENABLE();

  huart1.Instance = USART1;
  huart1.Init.BaudRate = 115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;

  HAL_UART_Init(&huart1);
}

//////////////////////////////////////////////////////////
// CLOCK CONFIG
//////////////////////////////////////////////////////////
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSIDiv = RCC_HSI_DIV1;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;

  HAL_RCC_OscConfig(&RCC_OscInitStruct);

  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK |
                               RCC_CLOCKTYPE_SYSCLK |
                               RCC_CLOCKTYPE_PCLK1;

  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0);
}