#include "stm32l0xx_hal.h"


// Define the GPIO pins for the segments
#define SEG_A_PIN GPIO_PIN_0
#define SEG_B_PIN GPIO_PIN_1
#define SEG_C_PIN GPIO_PIN_2
#define SEG_D_PIN GPIO_PIN_3
#define SEG_E_PIN GPIO_PIN_4
#define SEG_F_PIN GPIO_PIN_5
#define SEG_G_PIN GPIO_PIN_6
#define SEG_PORT GPIOA

// Define the GPIO pins for button
#define BUTTON_PIN GPIO_PIN_4
#define BUTTON_GPIO_PORT GPIOB

// Segment definitions for displaying digits 0-9 on a common cathode display
const uint8_t digit_segments[10] = {
    0b00111111, // 0
    0b00000110, // 1
    0b01011011, // 2
    0b01001111, // 3
    0b01100110, // 4
    0b01101101, // 5
    0b01111101, // 6
    0b00000111, // 7
    0b01111111, // 8
    0b01101111  // 9
};

// Function prototypes
void SystemClock_Config(void);
void GPIO_Init(void);
void display_digit(uint8_t digit);

uint8_t time_l = 0;
float time = 0.f;

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

    while (1)
    {
      HAL_Delay(1);

      if (HAL_GPIO_ReadPin(BUTTON_GPIO_PORT, BUTTON_PIN) == GPIO_PIN_SET)
      {
        if (time_l != (uint8_t)time)
        {
          time_l = (uint8_t)time; 
          display_digit(time_l);
        }
        
        time += 0.001;
        if (time > 10.f) time = 0.f;
      }
      else
      {
        display_digit(0);
        time = 0;
      }
    }
}

void SystemClock_Config(void)
{
    // Configure the system clock to 16 MHz
    RCC_OscInitTypeDef RCC_OscInitStruct = {0};
    RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
    RCC_OscInitStruct.HSIState = RCC_HSI_ON;
    RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
    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);
}

void GPIO_Init(void)
{
    __HAL_RCC_GPIOA_CLK_ENABLE();
    __HAL_RCC_GPIOB_CLK_ENABLE();

    GPIO_InitTypeDef GPIO_InitStruct = {0};

    // Configure segment pins
    GPIO_InitStruct.Pin = SEG_A_PIN | SEG_B_PIN | SEG_C_PIN | SEG_D_PIN |
                          SEG_E_PIN | SEG_F_PIN | SEG_G_PIN;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    // Configure GPIO pin for button (PA1)
    GPIO_InitStruct.Pin = BUTTON_PIN;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(BUTTON_GPIO_PORT, &GPIO_InitStruct);
}

void display_digit(uint8_t digit) {
    if (digit > 9) return; // Only handle digits 0-9
    uint8_t segments = digit_segments[digit];

    HAL_GPIO_WritePin(SEG_PORT, SEG_A_PIN, (segments & 0b00000001) ? GPIO_PIN_SET : GPIO_PIN_RESET);
    HAL_GPIO_WritePin(SEG_PORT, SEG_B_PIN, (segments & 0b00000010) ? GPIO_PIN_SET : GPIO_PIN_RESET);
    HAL_GPIO_WritePin(SEG_PORT, SEG_C_PIN, (segments & 0b00000100) ? GPIO_PIN_SET : GPIO_PIN_RESET);
    HAL_GPIO_WritePin(SEG_PORT, SEG_D_PIN, (segments & 0b00001000) ? GPIO_PIN_SET : GPIO_PIN_RESET);
    HAL_GPIO_WritePin(SEG_PORT, SEG_E_PIN, (segments & 0b00010000) ? GPIO_PIN_SET : GPIO_PIN_RESET);
    HAL_GPIO_WritePin(SEG_PORT, SEG_F_PIN, (segments & 0b00100000) ? GPIO_PIN_SET : GPIO_PIN_RESET);
    HAL_GPIO_WritePin(SEG_PORT, SEG_G_PIN, (segments & 0b01000000) ? GPIO_PIN_SET : GPIO_PIN_RESET);
}