#define gre 4
#define yel 3
#define red 2
#define blu 5

#define buz 10

#define b50c 8
#define b1e 7
#define b2e 6
#define bdis 9

float credit = 0;
float price = 1.5;

enum State {
  IDLE,
  PROCESSING,
  DISPENSING,
  CHANG,
  ERROR
};

void setLeds(bool b, bool g, bool y, bool r){
  digitalWrite(blu, b);
  digitalWrite(gre, g);
  digitalWrite(yel, y);
  digitalWrite(red, r);
}

bool bHandler(int pin){
  if(digitalRead(pin) == LOW){
    delay(200);
    return true;
  }
  else{
    return false;
  }
}

void beep(int duration) {
  tone(buz, 1000);
  delay(duration);
  noTone(buz);
}

void coinHandler(){
  if (bHandler(b50c)) {
    credit += 0.5;
    beep(500);

    Serial.print("Credit: ");
    Serial.println(credit);
  }
  if (bHandler(b1e)) {
    credit += 1.0;
    beep(500);

    Serial.print("Credit: ");
    Serial.println(credit);
  }
  if (bHandler(b2e)) {
    credit += 2.0;
    beep(500);

    Serial.print("Credit: ");
    Serial.println(credit);
  }
}

void changeFunction(){

  float change = credit - price;
  Serial.print("Returned ");
  Serial.println(change);

  for (int i = 0; i < 3; i++) {
    digitalWrite(blu, HIGH);
    tone(buz, 1000);
    delay(300);

    digitalWrite(blu, LOW);
    noTone(buz);
    delay(300);
  }

  credit = 0;
  Serial.println("Credit reset to 0");
}

bool errorBlink(){
  for(int i = 0; i < 3; i++){
   digitalWrite(red, HIGH);
   delay(200);
   digitalWrite(red,LOW);
   delay(200);
  }
}



void setup() {
  // put your setup code here, to run once:
  pinMode(gre, OUTPUT);
  pinMode(yel, OUTPUT);
  pinMode(red, OUTPUT);
  pinMode(blu, OUTPUT);

  pinMode(buz, OUTPUT);

  pinMode(b50c, INPUT_PULLUP);
  pinMode(b1e, INPUT_PULLUP);
  pinMode(b2e, INPUT_PULLUP);
  pinMode(bdis, INPUT_PULLUP);

  Serial.begin(9600);

  setLeds(0,1,0,0);
  Serial.print("Credit: ");
  Serial.println(credit);
}

State curState = IDLE;

bool disState = true;


void loop() {
  // put your main code here, to run repeatedly:
  coinHandler();

  switch(curState){

    case IDLE:
      setLeds(0,1,0,0);

      if (bHandler(bdis)) {
        if (credit >= price) {
          curState = PROCESSING;
        } else {
          curState = ERROR;
        }
      }
      break;

    case PROCESSING:
      setLeds(0,0,1,0);
      delay(1000);

      if(disState){
        curState = DISPENSING;
        disState = false;
        break;
      }
      else{
        curState = IDLE;
        disState = true;
        Serial.print("Credit: ");
        Serial.println(credit);
        break;
      }

    case DISPENSING:
      setLeds(0,0,0,1);

      tone(buz, 1000);
      delay(500);
      noTone(buz);

      delay(2000);
      

    case CHANG:
      setLeds(1,0,0,0);

      changeFunction();
      curState = PROCESSING;
      break;

    case ERROR:
      setLeds(0,0,0,1);
      errorBlink();
      curState = IDLE;
      break;
  }
}