#include <LiquidCrystal_PCF8574.h>
#include <Wire.h>
#include <time.h>

int userArrowPos = 0;
int targetArrowPos;

unsigned long startTime;

//initialize the liquid crystal library
//the first parameter is the address
LiquidCrystal_PCF8574 lcd(0x27);

int analogInPin = A0;
int sensorValue = 0;

byte upArrow[8] = {
  0b00100,
  0b01110,
  0b10101,
  0b00100,
  0b00100,
  0b00100,
  0b00100,
  0b00000
};

byte downArrow[8] = {
  0b00100,
  0b00100,
  0b00100,
  0b00100,
  0b10101,
  0b01110,
  0b00100,
  0b00000
};

bool runComplete = false;
void setup() {
//initialize lcd screen
lcd.begin(16, 2);
// turn on the backlight
lcd.setBacklight(255);

lcd.createChar(0, upArrow);
lcd.createChar(1, downArrow);

pinMode(2, INPUT_PULLUP);
pinMode(3, OUTPUT);

randomSeed(analogRead(0));
targetArrowPos = random(0, 16);
drawDownArrow();
startTime = millis();
lcd.setCursor(userArrowPos, 1);
lcd.write(byte(0));
}

void drawDownArrow() {
  lcd.setCursor(targetArrowPos, 0);
  lcd.write(byte(1));
}

void drawUpArrow() {
      lcd.setCursor(userArrowPos, 1);
      lcd.write(byte(0));
}



void loop() {
  // put your main code here, to run repeatedly:
    sensorValue = analogRead(analogInPin);

    int mappedVal =  map(sensorValue, 0, 1023, 0, 15);

    if(userArrowPos !=  mappedVal) {
      userArrowPos = mappedVal;
      lcd.clear();
      drawDownArrow();
      drawUpArrow();
    }

  if(digitalRead(2) == LOW) {
    if(userArrowPos != targetArrowPos) {
      tone(3, 3000);
      delay(2000);
      noTone(3);
    } else {

      lcd.clear();
      unsigned long finishTime = millis() - startTime;
      lcd.print(finishTime);
      delay(2000);
      lcd.clear();
      targetArrowPos = random(0, 16);
      drawDownArrow();
      drawUpArrow();
      startTime = millis();
    }
  }  
  
  


}