/*
  State change detection (edge detection)

  Wokwi sim  https://wokwi.com/projects/365743943712748545
  based on: https://wokwi.com/projects/365724367327685633

  Modified from https://www.arduino.cc/en/Tutorial/BuiltInExamples/StateChangeDetection
    to use INPUT_PULLUP
    to measure and report time-in-state
    to add a state machine per 
    for https://forum.arduino.cc/t/search-and-destroy-bomb-prop-for-paintball/1130728/8?u=davex

  Often, you don't need to know the state of a digital input all the time, but
  you just need to know when the input changes from one state to another.
  For example, you want to know when a button goes from OFF to ON. This is called
  state change detection, or edge detection.

  This example shows how to detect when a button or button changes from off to on
  and on to off.

  The circuit:
  - pushbutton attached to pin 2 from GND
  - LED attached from pin 13 to ground through 220 ohm resistor (or use the
    built-in LED on most Arduino boards)

  created  27 Sep 2005
  modified 30 Aug 2011
  by Tom Igoe

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/StateChangeDetection
*/

// this constant won't change:
const int  buttonPin = 2;    // the pin that the pushbutton is attached to
const int ledPin = 13;       // the pin that the LED is attached to

// Variables will change:
int buttonPushCounter = 0;   // counter for the number of button presses
int buttonState = 0;         // current state of the button
int lastButtonState = 0;     // previous state of the button
unsigned long lastChangeMs = 0; // time of last state change
unsigned long lastLowMs = 0; // time of last state change

void setup() {
  // initialize the button pin as a input:
  pinMode(buttonPin, INPUT_PULLUP);
  // initialize the LED as an output:
  pinMode(ledPin, OUTPUT);
  // initialize serial communication:
  Serial.begin(9600);
}


unsigned long countdownStartMs = 0;
int armed = false;
unsigned long startOfStateMs = 0;




void loop() {
  // read the pushbutton input pin:
  buttonState = digitalRead(buttonPin);
  unsigned long now = millis();

  // compare the buttonState to its previous state
  if (buttonState != lastButtonState) {
    // if the state has changed, increment the counter
    lastChangeMs = now;
    if (buttonState == LOW) {
      // if the current state is HIGH then the button went from off to on:
      buttonPushCounter++;
      lastLowMs = now;
      Serial.println("on");
      Serial.print("number of button pushes: ");
      Serial.println(buttonPushCounter);
    } else {
      // if the current state is LOW then the button went from on to off:
      Serial.println("off");
    }
    // Delay a little bit to avoid bouncing
    delay(50);
  }
  // save the current state as the last state, for next time through the loop
  lastButtonState = buttonState;
 
  switch (armed) { // transition based on arm-state and button
    case 0: // idle
      if (buttonState == LOW && now - lastLowMs > 15000UL) {
        armed = 1;
        countdownStartMs = now;
        changeArming(1);
        digitalWrite(ledPin, HIGH);
      }
      break;
    case 1: // armed and counting
      if (now - startOfStateMs > 60000UL) { // boom
        Serial.print("boom");
        changeArming(5);
      }
      if (buttonState == LOW && now - lastLowMs > 15000UL) { // disarmed
        changeArming(0);
        digitalWrite(ledPin, LOW);
      }
      break;
    case 5: // boom
      Serial.print("B");
      if (buttonState == LOW && now - lastLowMs > 15000UL) { // disarmed
        changeArming(0);
        digitalWrite(ledPin, LOW);
      }
  }
  report();
}

void changeArming(int newState) {
  unsigned long now = millis();
  armed = newState;
  startOfStateMs = now; // record transition time
  lastChangeMs = now; // reset button time
  lastLowMs = now;
}

void report() {
  unsigned long interval = 250;
  static unsigned long last = 0;
  unsigned long now = millis();
  if (now - last >= interval) {
    last = now;
    Serial.print("state:");
    Serial.print(buttonState == HIGH ? "HIGH" : "LOW" );
    Serial.print(" time:");
    Serial.print( now - lastChangeMs );
    Serial.print(" armed:");
    Serial.print(armed);
    if (armed) {
      Serial.print(" armedTime:");
      Serial.print(now - countdownStartMs);
    }
    Serial.println();
  }
}