/*
https://forum.arduino.cc/t/button-timer-with-pwm-output/1419547/
*/



#define BTN_PIN 2
#define LED_PIN 11
#define POT_PIN A0
#define POT2_PIN A1


unsigned long lastBtn;
unsigned long btnDebounce = 50;
byte btnState = HIGH;


unsigned long ledStart;
unsigned long ledRunTime = 500;

enum StatesSystem {
  state_Idle,
  state_Wait,
  state_Run
};

StatesSystem sysState = state_Idle;

unsigned long waitStart;
unsigned long waitTime = 1000;

void setup() {
  Serial.begin(115200);
  pinMode(BTN_PIN, INPUT_PULLUP);

}

void loop() {

  unsigned long now = millis();
  
  int v;
  
  v = analogRead(POT2_PIN);
  waitTime = map(v, 0, 1023, 10, 2000); 


  if (now - lastBtn >= btnDebounce) {
    byte b = digitalRead(BTN_PIN);
    if (b != btnState) {
      lastBtn = now;
      btnState = b;
      if (b == HIGH) {
        //press and release
        if (sysState == state_Idle) {
          sysState = state_Wait;
          waitStart = now;
        }
      }
    }
  }


  switch (sysState) {
    case state_Wait: 
       if (now - waitStart >= waitTime) {
        sysState = state_Run;
        ledStart = now;
       }
      break;
    case state_Run:
       if (now - ledStart >= ledRunTime) {
        //stop
        stateSys = state_Idle;
        analogWrite(LED_PIN, 0);
       } else {
        //led is active..
        v = analogRead(POT_PIN);
        v = map(v, 0, 1023, 0, 255);
        analogWrite(LED_PIN, v);
       }
      break;
  }


}