/* USER CODE BEGIN Header */
/**
 ******************************************************************************
 * @file           : main.c
 * @brief          : Main program body
 ******************************************************************************
 * @attention
 *
 * Copyright (c) 2025 STMicroelectronics.
 * All rights reserved.
 *
 * This software is licensed under terms that can be found in the LICENSE file
 * in the root directory of this software component.
 * If no LICENSE file comes with this software, it is provided AS-IS.
 *
 ******************************************************************************
 */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <stdio.h>

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

// --- User pins (as requested) ---
#define BTN_GPIO_Port     GPIOC
#define BTN_Pin           GPIO_PIN_0

#define LED1_GPIO_Port    GPIOA
#define LED1_Pin          GPIO_PIN_6        // LED1 → PA6
#define LED2_GPIO_Port    GPIOA
#define LED2_Pin          GPIO_PIN_7        // LED2 → PA7

// --- Timing (ms) ---
#define DEBOUNCE_MS       50u
#define LONG_PRESS_MS     1000u
#define DOUBLE_GAP_MS     500u

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
TIM_HandleTypeDef htim2;
TIM_HandleTypeDef htim3;

UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */

// Button handling state (all modified in ISRs)
static volatile uint8_t  debouncing = 0;                // 1 while debounce timer running
static volatile GPIO_PinState last_stable_level = GPIO_PIN_SET; // pulled-up idle (not pressed)
static volatile uint32_t press_time_ms = 0;             // timestamp at press
static volatile uint8_t  short_press_count = 0;         // counts short presses awaiting classification

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_TIM2_Init(void);
static void MX_TIM3_Init(void);
/* USER CODE BEGIN PFP */

static void start_debounce_timer(void);
static void stop_debounce_timer(void);
static void start_double_timer(void);
static void stop_double_timer(void);
static void on_button_state_change(GPIO_PinState new_level);
static void do_single_press_action(void);
static void do_double_press_action(void);
static void do_long_press_action(void);

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

// Helper: configure TIM base for a one-shot duration in ms
static void TIM_OneShot_Arm(TIM_HandleTypeDef *htim, uint32_t duration_ms)
{
  __HAL_TIM_DISABLE_IT(htim, TIM_IT_UPDATE);
  __HAL_TIM_SET_COUNTER(htim, 0);
  __HAL_TIM_CLEAR_FLAG(htim, TIM_FLAG_UPDATE);
  __HAL_TIM_SET_AUTORELOAD(htim, duration_ms); // period equals ms when prescaler makes 1 kHz
  __HAL_TIM_ENABLE_IT(htim, TIM_IT_UPDATE);
  HAL_TIM_Base_Start(htim);
}

static void TIM_OneShot_Disarm(TIM_HandleTypeDef *htim)
{
  HAL_TIM_Base_Stop(htim);
  __HAL_TIM_DISABLE_IT(htim, TIM_IT_UPDATE);
  __HAL_TIM_CLEAR_FLAG(htim, TIM_FLAG_UPDATE);
}


// === EXTI callback: edge detected on PC0 ===
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
  if (GPIO_Pin != BTN_Pin) return;

  if (debouncing) {
    // Ignore bounces while debounce timer active
    return;
  }

  // Start debounce one-shot and mask EXTI until done
  debouncing = 1;
  HAL_NVIC_DisableIRQ(EXTI0_IRQn);
  start_debounce_timer();
}

// === TIM Period Elapsed callback ===
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  if (htim->Instance == TIM2) {
    // Debounce window ended -> sample stable level, process change
    stop_debounce_timer();

    GPIO_PinState stable_level = HAL_GPIO_ReadPin(BTN_GPIO_Port, BTN_Pin);
    if (stable_level != last_stable_level) {
      on_button_state_change(stable_level);
      last_stable_level = stable_level;
    }

    debouncing = 0;
    __HAL_GPIO_EXTI_CLEAR_IT(BTN_Pin);
    HAL_NVIC_EnableIRQ(EXTI0_IRQn);
  }
  else if (htim->Instance == TIM3) {
    // Double-click window ended -> decide single/double
    stop_double_timer();

    if (short_press_count == 1) {
      do_single_press_action();
    } else if (short_press_count >= 2) {
      do_double_press_action();
    }
    short_press_count = 0;
  }
}

// --- State machine on stable edge after debounce ---
static void on_button_state_change(GPIO_PinState  new_level)
{
  if (new_level == GPIO_PIN_RESET) {
    // Pressed (active-LOW)
    press_time_ms = HAL_GetTick();
  } else {
    // Released
    uint32_t dur = HAL_GetTick() - press_time_ms;

    if (dur >= LONG_PRESS_MS) {
      // Long press -> turn both LEDs OFF, cancel any pending single/double
      do_long_press_action();
      short_press_count = 0;
      stop_double_timer();
    } else {
      // Short press -> count and (re)arm double-click timer
      short_press_count++;
      start_double_timer();
    }
  }
}

// --- Actions ---
static void do_single_press_action(void)
{
  HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin); // Single -> toggle LED1
}

static void do_double_press_action(void)
{
  HAL_GPIO_TogglePin(LED2_GPIO_Port, LED2_Pin); // Double -> toggle LED2
}

static void do_long_press_action(void)
{
  HAL_GPIO_WritePin(LED1_GPIO_Port, LED1_Pin, GPIO_PIN_RESET);
  HAL_GPIO_WritePin(LED2_GPIO_Port, LED2_Pin, GPIO_PIN_RESET); // Long -> both OFF
}

// --- Timer helpers ---
static void start_debounce_timer(void)
{
  __HAL_TIM_SET_AUTORELOAD(&htim2, DEBOUNCE_MS);
  TIM_OneShot_Arm(&htim2, DEBOUNCE_MS);
}

static void stop_debounce_timer(void)
{
  TIM_OneShot_Disarm(&htim2);
}

static void start_double_timer(void)
{
  // (Re)start window
  __HAL_TIM_SET_AUTORELOAD(&htim3, DOUBLE_GAP_MS);
  TIM_OneShot_Disarm(&htim3);
  TIM_OneShot_Arm(&htim3, DOUBLE_GAP_MS);
}

static void stop_double_timer(void)
{
  TIM_OneShot_Disarm(&htim3);
}


/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART2_UART_Init();
  MX_TIM2_Init();
  MX_TIM3_Init();
  /* USER CODE BEGIN 2 */

  // Ensure LEDs start OFF
  HAL_GPIO_WritePin(LED1_GPIO_Port, LED1_Pin, GPIO_PIN_RESET);
  HAL_GPIO_WritePin(LED2_GPIO_Port, LED2_Pin, GPIO_PIN_RESET);

  // Set initial stable level based on current pin (pulled-up expected)
  last_stable_level = HAL_GPIO_ReadPin(BTN_GPIO_Port, BTN_Pin);

  // Enable EXTI interrupt line (done in MX_GPIO_Init), just to be explicit:
  HAL_NVIC_EnableIRQ(EXTI0_IRQn);

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
	while (1) {

    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
	}
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief TIM2 Initialization Function
  * @param None
  * @retval None
  */
static void MX_TIM2_Init(void)
{

  /* USER CODE BEGIN TIM2_Init 0 */

  /* USER CODE END TIM2_Init 0 */

  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  /* USER CODE BEGIN TIM2_Init 1 */

  /* USER CODE END TIM2_Init 1 */
  htim2.Instance = TIM2;
  htim2.Init.Prescaler = 64000-1;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 50;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM2_Init 2 */

  HAL_NVIC_SetPriority(TIM2_IRQn, 1, 0);
  HAL_NVIC_EnableIRQ(TIM2_IRQn);


  /* USER CODE END TIM2_Init 2 */

}

/**
  * @brief TIM3 Initialization Function
  * @param None
  * @retval None
  */
static void MX_TIM3_Init(void)
{

  /* USER CODE BEGIN TIM3_Init 0 */

  /* USER CODE END TIM3_Init 0 */

  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  /* USER CODE BEGIN TIM3_Init 1 */

  /* USER CODE END TIM3_Init 1 */
  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 64000-1;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 500;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM3_Init 2 */

  HAL_NVIC_SetPriority(TIM3_IRQn, 2, 0);
  HAL_NVIC_EnableIRQ(TIM3_IRQn);

  /* USER CODE END TIM3_Init 2 */

}

/**
  * @brief USART2 Initialization Function
  * @param None
  * @retval None
  */
static void MX_USART2_UART_Init(void)
{

  /* USER CODE BEGIN USART2_Init 0 */

  /* USER CODE END USART2_Init 0 */

  /* USER CODE BEGIN USART2_Init 1 */

  /* USER CODE END USART2_Init 1 */
  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;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART2_Init 2 */

  /* USER CODE END USART2_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  /* USER CODE BEGIN MX_GPIO_Init_1 */

  /* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_6|GPIO_PIN_7, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC0 */
  GPIO_InitStruct.Pin = GPIO_PIN_0;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING_FALLING;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pins : PA6 PA7 */
  GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7;
  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);

  /* EXTI interrupt init*/
  HAL_NVIC_SetPriority(EXTI0_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(EXTI0_IRQn);

  /* USER CODE BEGIN MX_GPIO_Init_2 */

  /* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
	/* User can add his own implementation to report the HAL error return state */
	__disable_irq();
	while (1) {
	}
  /* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
