#include <LiquidCrystal_I2C.h>

int ledPinR1 =19;//red light if jumped line
int ledPinG1 =18;//green light if sucessful 
int ledPinY3 =8;//indicator light 3
int ledPinY2 =9;//indicator light 2
int ledPinY1 =10;//indicator light 1
int ledPinStageY1 =17;//staging light 1
int ledPinStageY2 = 16;//staging light 2
int buttonPin = 7;//button used to play game
int reactionTime;//holds final reaction time
int stage = 0;//holds each stage of the game
unsigned long startTime;//gets start time
unsigned long endTime;//gets end time
unsigned long rollout=240;//a delay for a drag car to actual start rolling due to the time it takes the powertrain to react
LiquidCrystal_I2C lcd(0x27, 16, 2);


void setup() {
  // put your setup code here, to run once:
pinMode(ledPinR1, OUTPUT);
pinMode(ledPinG1, OUTPUT);
pinMode(ledPinY3, OUTPUT);
pinMode(ledPinY2, OUTPUT);
pinMode(ledPinY1, OUTPUT);
pinMode(ledPinStageY1, OUTPUT);
pinMode(ledPinStageY2, OUTPUT);
pinMode(buttonPin, INPUT_PULLUP);

lcd.begin(20, 2);
lcd.backlight();
lcd.print("Reaction Time:");
Serial.begin(9600); 
}

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

  lcd.setCursor(0, 1);
    
     //stops after each round and displays both staging lights to indicate ready
    if (digitalRead(buttonPin) == HIGH  && stage == 3) 
    {     
     
       digitalWrite(ledPinStageY1,HIGH);
       digitalWrite(ledPinStageY2,HIGH);
      delay(2000);
      //sets stage to ready
       stage = 0; 
     } 

    //user indicated ready and now timer starts 
    if (digitalRead(buttonPin) == LOW  && stage == 0) 
    {     
       
       digitalWrite(ledPinStageY1,HIGH);
       digitalWrite(ledPinStageY2,HIGH);
       startTime = millis();
       stage = 1;
       delay(500);
      
     } 
     
        //round finished and timer stopped
        if (digitalRead(buttonPin) == HIGH && stage ==1)
         {
             endTime = millis();
              digitalWrite(ledPinStageY2,LOW);
              digitalWrite(ledPinStageY1,LOW);
              digitalWrite(ledPinY1,LOW);
              digitalWrite(ledPinY2,LOW);
              digitalWrite(ledPinY3,LOW);
              stage =2;
         }

        //results sent here to indicate green or red light 
        if (stage ==2)
         { 
            //shows green if the user pressed button after yellow
            if((endTime+rollout) - startTime >=2000)
            {
            displayreactiontime();
            
            digitalWrite(ledPinG1,HIGH);
            delay(3000);
            digitalWrite(ledPinG1,LOW);
            stage=3;
            }
            //shows red if user pushed button before yellow
            if((endTime+rollout) - startTime <=2000)
            {
              //displays reaction time
            displayreactiontime();
            digitalWrite(ledPinR1,HIGH);
            delay(3000);
            digitalWrite(ledPinR1,LOW);
            stage=3;
            }
        
         }

        //used to go through 3 indicating lights
        if (digitalRead(buttonPin) == LOW  && stage ==1)        
        
         {
            if(millis() - startTime >= 500)
            {
            digitalWrite(ledPinY1, HIGH);  // Update the actual LED
            }
            if( millis() - startTime >= 1000)
            {
            digitalWrite(ledPinY1, LOW);  // Update the actual LED 
            digitalWrite(ledPinY2, HIGH);  // Update the actual LED
            }
            if(millis() - startTime >= 1500)
            {
            digitalWrite(ledPinY2, LOW);  // Update the actual LED
            digitalWrite(ledPinY3, HIGH);  // Update the actual LED
            }
            if(millis() - startTime >= 2000)
            {
            digitalWrite(ledPinY3, LOW);  // Update the actual LED
          
            } 
          }
 
        
}
//method calculates time
void displayreactiontime()
{
reactionTime = ((endTime+rollout)-startTime)- 2000;
Serial.print("Reaction time = ");
Serial.println(reactionTime);
lcd.println(reactionTime);
}