// constants won't change. Used here to set a pin number:
const int cncReady = 8;  // the number of the LED pin
const int cncRunning = 12;  // the number of the LED pin 2
const int cncStart = 9;    //mimics the start button
int modeState = 0;         
const int machineSateLED = 6;    //mimics the state machine wether it is running or at rest.
const int button1 = 2;
const int button3 = 3;
const int button4 = 4;
const int resetButton = 5;
const int debugPin = A4; 
unsigned long currentMillis = 0;
bool lastBtnState = false;
int mode = 0;
bool startCncInput = 0;
long interval = 0;  // interval at which machine state LED blinks (milliseconds)
// Variables will change:
int machineState = LOW;  // ledState used to set the LED
int machineToolRunning = 0;   // saves the machine state (running / not running)
unsigned long previousMillis = 0;  // will store last time LED was updated

void setup() {
  // set the digital pin as output:
  pinMode(cncReady, OUTPUT);
  pinMode(cncRunning, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(cncStart, INPUT);
  // Set the 3 different buttons for the 3 different modes as input 
  pinMode(button1, INPUT);
  pinMode(button3, INPUT);
  pinMode(button4, INPUT);
  pinMode(resetButton, INPUT);
  //setting debug pin to putput
  pinMode(debugPin, OUTPUT);
  //setting the machine state LED as output
  pinMode(machineSateLED, OUTPUT);
  //digitalWrite(machineSateLED , HIGH);

  digitalWrite(cncReady , HIGH);
  digitalWrite(cncRunning , LOW);

  lastBtnState = digitalRead(cncStart); 
}


void mode_1(){
  switch (modeState){
      //state of initiating the 
    	case 0:
      machineToolRunning = 1;
      digitalWrite(cncReady, LOW);
      digitalWrite(cncRunning, HIGH);
      modeState = 1;
      interval = 2000;
      previousMillis = millis();
      break;
      case 1:
      async_delay(2);
      break;
      case 2:
  	  digitalWrite(cncReady, HIGH);
      digitalWrite(cncRunning, LOW);
      modeState = 0;
      machineToolRunning = 0;
      break;
  }
}


void mode_3(){  
    switch (modeState){
    	case 0:
      machineToolRunning = 1;
      digitalWrite(cncReady, LOW);
      modeState = 1;
      interval = 2000;
      previousMillis = millis();
      break;
      case 1:
      async_delay(2);
      break;
      case 2:
  	  digitalWrite(cncReady, HIGH);
      modeState = 0;
      machineToolRunning = 0;
      break;
  }
}


void mode_4(){
    switch (modeState){
    	case 0:
      interval = 3000;
      previousMillis = millis();
      async_delay(1);
      break;
      case 1:
      machineToolRunning = 1;
      digitalWrite(cncReady, LOW);
      digitalWrite(cncRunning, HIGH);
      modeState = 2;
      interval = 5000;
      previousMillis = millis();
      break;
      case 2:
      async_delay(3);
      break;
      case 4:
  	  digitalWrite(cncReady, HIGH);
      digitalWrite(cncRunning, LOW);
      modeState = 0;
      machineToolRunning = 0;
      break;
  }
}

//switch case for going to specific mode according to clicked pushbutton
void handling_state(){
  switch (mode){
      case 1:
      mode_1();
      break;

      case 3:
      mode_3();
      break;

      case 4:
      mode_4();
      break;

      // This sets the default mode to 1 in case no pushbutton is clicked.
      default:
      mode_1();
      break;
    }
}

//
void reset(){
  previousMillis = millis()+interval; 
  modeState = 0;
  machineToolRunning = 0;
}

//Asynchronous timer 
void async_delay(int state){
  currentMillis = millis();
    if (currentMillis - previousMillis >= interval) {
      previousMillis = currentMillis;
      modeState = state;
    }
}

void machineStateBlink(){

  // check to see if it's time to blink the LED; that is, if the difference
  // between the current time and last time you blinked the LED is bigger than
  // the interval at which you want to blink the LED.
  /*unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    // save the last time you blinked the LED
    previousMillis = currentMillis;
  */
    // if the LED is off turn it on and vice-versa:
    if (machineState == HIGH) {
      machineState = LOW;
    } else {
      machineState = HIGH;
    }
    // set the LED with the ledState of the variable:
    digitalWrite(machineSateLED , machineState);
    //delay(500);
}

void loop() {
  // here is where you'd put code that needs to be running all the time.
  // read the state of the pushbutton value:
  if (digitalRead(button1)) {mode = 1; reset();}
  if (digitalRead(button3)) {mode = 3; reset();}
  if (digitalRead(button4)) {mode = 4; reset();}
  //reset the mode selected when the reset button is pressed
  if (digitalRead(resetButton)){machineToolRunning= 0; mode = 0; machineState = LOW;}

  //the following nested if statements are to make sure that you 
  // 1- User wasn't keeping the pushbutton clicked when the cycle ended
  // 2- User clicked the pushbutton when machine was ready
  // 3- User didn't click the pushbutton when a cycle was running
  if (digitalRead(cncStart) != lastBtnState){
    lastBtnState = digitalRead(cncStart); 
    if (lastBtnState && !machineToolRunning) {
      machineToolRunning =1;
      }
  }

  //this for debouncing after clicking on any pushbutton
  while (digitalRead(button1) || digitalRead(button3) || digitalRead(button4)){
    delay(10);
  }
  
  // handle the chosen mode after making sure of conditions 1,2,3 as written in the comments above
  if (machineToolRunning){
      handling_state();
      //machineStateBlink();
  }
  //this delay is for debounce after clicking on the cncStart input button
  delay(10);
}