#include "stm32c0xx_hal.h"

/* ADC handle */
ADC_HandleTypeDef hadc1;

/* Stepper motor pins */
#define DIR_Pin  GPIO_PIN_8
#define DIR_Port GPIOA
#define STEP_Pin GPIO_PIN_9
#define STEP_Port GPIOA

/* Function prototypes */
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_ADC1_Init(void);

/* Set motor direction */
void Set_Direction(uint8_t val) {
    HAL_GPIO_WritePin(DIR_Port, DIR_Pin, val ? GPIO_PIN_SET : GPIO_PIN_RESET);
}

/* Make one step */
void Step() {
    HAL_GPIO_WritePin(STEP_Port, STEP_Pin, GPIO_PIN_SET);
    HAL_Delay(1);  
    HAL_GPIO_WritePin(STEP_Port, STEP_Pin, GPIO_PIN_RESET);
    HAL_Delay(1);
}

/* Read ADC value */
uint32_t Read_ADC() {
    HAL_ADC_Start(&hadc1);
    HAL_ADC_PollForConversion(&hadc1, HAL_MAX_DELAY);
    return HAL_ADC_GetValue(&hadc1);
}

/* Main program */
int main(void)
{
    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();
    MX_ADC1_Init();

    uint32_t target_angle = 0;
    uint32_t current_angle = 0;

    while (1)
    {
        target_angle = Read_ADC();
        target_angle = (target_angle * 200) / 4095; // Scale to steps

        if(current_angle < target_angle) {
            Set_Direction(1); // clockwise
            Step();
            current_angle++;
        }
        else if(current_angle > target_angle) {
            Set_Direction(0); // counter-clockwise
            Step();
            current_angle--;
        }
        HAL_Delay(2);
    }
}

/* System Clock Configuration */
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;
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { while(1); }

    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_APB1_DIV1;
    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK) { while(1); }
}

/* GPIO Initialization */
static void MX_GPIO_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};
    __HAL_RCC_GPIOA_CLK_ENABLE();

    GPIO_InitStruct.Pin = DIR_Pin | STEP_Pin;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

/* ADC1 Initialization */
static void MX_ADC1_Init(void)
{
    ADC_ChannelConfTypeDef sConfig = {0};

    hadc1.Instance = ADC1;
    hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2;
    hadc1.Init.Resolution = ADC_RESOLUTION_12B;
    hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
    hadc1.Init.ScanConvMode = ADC_SCAN_DISABLE;
    hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
    hadc1.Init.LowPowerAutoWait = DISABLE;
    hadc1.Init.LowPowerAutoPowerOff = DISABLE;
    hadc1.Init.ContinuousConvMode = DISABLE;
    hadc1.Init.NbrOfConversion = 1;
    hadc1.Init.DiscontinuousConvMode = DISABLE;
    hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
    hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
    hadc1.Init.DMAContinuousRequests = DISABLE;
    hadc1.Init.Overrun = ADC_OVR_DATA_PRESERVED;
    hadc1.Init.SamplingTimeCommon1 = ADC_SAMPLETIME_1CYCLE_5;
    hadc1.Init.OversamplingMode = DISABLE;
    if (HAL_ADC_Init(&hadc1) != HAL_OK) { while(1); }

    sConfig.Channel = ADC_CHANNEL_7; // potentiometer
    sConfig.Rank = ADC_REGULAR_RANK_1;
    sConfig.SamplingTime = ADC_SAMPLINGTIME_COMMON_1;
    if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { while(1); }
}