#define DEBUG
const int numInputs = 3;
const int inputPins[numInputs] = {4, 3, 2};
const int numSteps = 5;
const int steps[numSteps] = {0, 2, 1, 1, 0};
const int ledPins[numSteps] = {12, 11, 10, 9, 8};
const int lockPin = A0;
bool lastInputState[] = {HIGH, HIGH, HIGH, HIGH};
int currentStep = 0;

unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

void setup() {
  // put your setup code here, to run once:
for(int i=0; i< numInputs; i++){
  pinMode(inputPins[i], INPUT_PULLUP);
}

for(int i=0; i< numSteps; i++){
  pinMode(ledPins[i], OUTPUT);
}

pinMode(lockPin, OUTPUT);
digitalWrite(lockPin, HIGH);

#ifdef DEBUG
Serial.begin(9600);
Serial.println(F("Serial communication started"));
#endif
}



void loop() {
 
if ( (millis() - lastDebounceTime) > debounceDelay) {
  for(int i=0; i<numInputs; i++){
    int currentInputState = digitalRead(inputPins[i]);

    if(currentInputState != lastInputState[i]) {
      lastDebounceTime = millis();
    }

   if(currentInputState == LOW && lastInputState[i] == HIGH) {
    if(steps[currentStep] == i){
      currentStep++;

      #ifdef DEBUG
      Serial.print(F("Correct input! Onto step #"));
      Serial.println(currentStep);
      #endif
    }
    else {
      currentStep = 0;
      Serial.println(F("Incorrect input! Back to begining!"));
    }
   }
   lastInputState[i] = currentInputState;
  }
} 
 
if(currentStep == numSteps) {
  onSolve();
} 

for(int i=0; i<numSteps; i++){
  digitalWrite(ledPins[i], (i< currentStep ? HIGH : LOW));
} 
}

void onSolve() {
  #ifdef DEBUG
  Serial.println(F("Puzzle Solved!"));
  #endif

  digitalWrite(lockPin, LOW);
  while(true){
    for(int i=0; i<numSteps; i++){
      digitalWrite(ledPins[i], HIGH);
      delay(100);
    }
    delay(100);
    for(int i=0; i<numSteps; i++){
    digitalWrite(ledPins[i], LOW);
    delay(100);  
    }
  }
}