#include "stm32c0xx_hal.h"

// Define pin numbers for start_stop, increment, and decrement buttons
  uint8_t startStopState;
  uint8_t incrementState;
  uint8_t decrementState;
  
void SystemClock_Config(void);

void displayCounter(int counter);

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

    // Initialize GPIO structures
    GPIO_InitTypeDef GPIO_InitStruct = {0};

    // Enable GPIO clock for Port A
    __HAL_RCC_GPIOA_CLK_ENABLE();

    // Enable GPIO clock for Port B
    __HAL_RCC_GPIOB_CLK_ENABLE();

    // Enable GPIO clock for Port D
    __HAL_RCC_GPIOD_CLK_ENABLE();

    // Configure pins PA0 - PA7 as output
    GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3 | GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6 | GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    // Configure pins PB0 - PB7 as output
    GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3 | GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6 | GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

    // Configure pins PD3, PB8, and PB9 as input with pull-up
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);   
    
    // Initial display
    displayCounter();

    // Initialize variables
    _Bool counting = 0;
    _Bool countingDirection = 1; // true for counting up, false for counting down
    int counterValue = 0;
    int decrementButtonPrevState = GPIO_PIN_RESET;
    int incrementButtonPrevState = GPIO_PIN_RESET;

  while (1) {
    int startStopState = HAL_GPIO_ReadPin(GPIOD, GPIO_PIN_3);
    int incrementState = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_8);
    int decrementState = HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_9);

    // Toggle counting state when the start/stop button is pressed
    if (startStopState == GPIO_PIN_SET) {
      counting = !counting; // Toggle counting state
      HAL_Delay(250); // Debounce delay
    }

    if (counting) {
      // Change counting direction when the decrement button is pressed
      if (decrementState == GPIO_PIN_SET && decrementButtonPrevState == GPIO_PIN_RESET) {
        countingDirection = 0; // Toggle counting direction
        HAL_Delay(250); // Debounce delay
      }

      // Change direction to count up if previously counting down
      if (incrementState == GPIO_PIN_SET && incrementButtonPrevState == GPIO_PIN_RESET && !countingDirection) {
        countingDirection = 1; // Change direction to count up
        HAL_Delay(250); // Debounce delay
      }

      // Increment or decrement counter based on counting direction
      counterValue = (counterValue + (countingDirection ? 1 : -1) + 10000) % 10000;
      // displayCounter(); // Update display (implementation dependent)
      HAL_Delay(250); // Debounce delay
    } else {
      // Increment or decrement counter by 1 when paused
      if (incrementState == GPIO_PIN_SET) {
        counterValue = (counterValue + 1) % 10000; // Increment counter
      } else if (decrementState == GPIO_PIN_SET) {
        counterValue = (counterValue - 1 + 10000) % 10000; // Decrement counter
      }

      // Update display if either increment or decrement button is pressed
      if (incrementState == GPIO_PIN_SET || decrementState == GPIO_PIN_SET) {
        // displayCounter(); // Update display (implementation dependent)
        HAL_Delay(250); // Debounce delay
      }
    }

    decrementButtonPrevState = decrementState;
    incrementButtonPrevState = incrementState;
  }
}


// display counter
void displayCounter(int counter) {

  // get each digit in different place
  int ones = counter%10;
  int tens = (counter/10)%10;
  int hundreds = (counter/100)%10;
  int thousands = counter/1000;

  // decode ones digit
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, (ones & 0x01) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, (ones & 0x02) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_2, (ones & 0x04) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_3, (ones & 0x08) ? GPIO_PIN_SET : GPIO_PIN_RESET);

  // decode tens digit
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_0, (tens & 0x01) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_1, (tens & 0x02) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_2, (tens & 0x04) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, (tens & 0x08) ? GPIO_PIN_SET : GPIO_PIN_RESET);

  // decode hundreds digit
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, (hundreds & 0x01) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, (hundreds & 0x02) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_6, (hundreds & 0x04) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_7, (hundreds & 0x08) ? GPIO_PIN_SET : GPIO_PIN_RESET);

  // decode tens digit
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_4, (thousands & 0x01) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, (thousands & 0x02) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, (thousands & 0x04) ? GPIO_PIN_SET : GPIO_PIN_RESET);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_7, (thousands & 0x08) ? GPIO_PIN_SET : GPIO_PIN_RESET);


}

// System Clock Configuration
void SystemClock_Config(void) {
    RCC_OscInitTypeDef RCC_OscInitStruct = {0};
    RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

    /** Configure the main internal regulator output voltage
    */
    __HAL_RCC_PWR_CLK_ENABLE();
   
    /** Initializes the CPU, AHB and APB busses clocks
    */
    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
    RCC_OscInitStruct.HSIState = RCC_HSI_ON;
    RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
   
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
        Error_Handler();
    }

  
}