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

ADC_HandleTypeDef hadc1;
UART_HandleTypeDef huart2;

void MX_GPIO_Init(void);
void MX_ADC1_Init(void);
void MX_USART2_UART_Init(void);

int main(void) {
  HAL_Init();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_ADC_CLK_ENABLE();
  
  MX_GPIO_Init();
  MX_ADC1_Init();
  MX_USART2_UART_Init();
  
  char buf[64];
  while (1) {
    HAL_ADC_Start(&hadc1);
    HAL_ADC_PollForConversion(&hadc1, 10);
    uint32_t value = HAL_ADC_GetValue(&hadc1);
    
    int wake = (value > 1800);
    
    sprintf(buf, "ADC:%lu Wake:%s\r\n", value, wake ? "YES" : "NO ");
    HAL_UART_Transmit(&huart2, (uint8_t*)buf, strlen(buf), 100);
    
    HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, wake ? GPIO_PIN_RESET : GPIO_PIN_SET);
    HAL_Delay(200);
  }
}

void MX_GPIO_Init(void) {
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_SET);  // LED OFF
  
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

void MX_ADC1_Init(void) {
  ADC_ChannelConfTypeDef sConfig = {0};
  
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.ContinuousConvMode = DISABLE;
  HAL_ADC_Init(&hadc1);

  sConfig.Channel = ADC_CHANNEL_0;  // PA0
  sConfig.Rank = ADC_REGULAR_RANK_1;
  HAL_ADC_ConfigChannel(&hadc1, &sConfig);
}

void MX_USART2_UART_Init(void) {
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  
  __HAL_RCC_USART2_CLK_ENABLE();
  
  // PA2-TX, PA3-RX with CORRECT AF9 for STM32C0
  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_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF9_USART2;  // FIXED!
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  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;
  HAL_UART_Init(&huart2);
}