read_button

uint8_t read_button()
{
  static boolean hold;
  static boolean button_a_state_prev;
  static boolean button_b_state_prev;
  static unsigned int button_a_time_prev;
  static unsigned int button_b_time_prev;
  
  boolean button_a_state = 1-digitalRead(button_a);  //pull up
  boolean button_b_state = 1-digitalRead(button_b);  //pull up
  unsigned long time = millis();
  
  if (button_a_state_prev == 0 && button_a_state == 1)
  {
    button_a_time_prev = time;
    hold = 1 ;
  }
  
  if (button_b_state_prev == 0 && button_b_state == 1)
  {
    button_b_time_prev = time;
    hold = 1 ;
  } 
  
  if (hold == 1)
  {
    if (button_a_state_prev == 1 && button_a_state == 0)
    {
      hold = 0;
      return 1;
    } 
    
    if (button_b_state_prev == 1 && button_b_state == 0)
    {
      hold = 0;
      return 2;
    } 
    
    if ((time - button_a_time_prev > 1000))
    {
      hold = 0;
      return 3;
    }
    
    if ((time - button_b_time_prev > 1000))
    {
      hold = 0;
      return 4;   
    }
    
    if (button_a_time_prev == button_b_time_prev)
    {
      hold = 0;
      return 5;      
    }
  }
  
  button_a_state_prev = button_a_state ;
  button_b_state_prev = button_b_state ;
  return 0;
}