#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define tacswitch 2
#define redled 8
#define yelled 9
#define greled 10

long starttime = millis();
float redrand = random(100, 2000);
float yelrand = random(100, 3000);

void setup() {
  Serial.begin(115200);

  pinMode(redled, OUTPUT);
  pinMode(yelled, OUTPUT);
  pinMode(greled, OUTPUT);
  pinMode(tacswitch, INPUT_PULLUP);
  digitalWrite(redled, LOW);
  digitalWrite(yelled, LOW);
  digitalWrite(greled, LOW);

  // SSD1306 display initialization
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  
  // Clear the display buffer
  display.clearDisplay();
  
  // Display initialization message with bigger font
  display.setTextSize(0); // Set text size to 2 (larger)
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,0);
  display.println("Reaction Time Game");
  display.println("");
  display.println("by Khairusthani");
  display.println("StudID 5223122214");
  display.display();
  delay(1000);
  display.clearDisplay();

  digitalWrite(redled,HIGH);
  delay(redrand);
  digitalWrite(redled,LOW);

  digitalWrite(yelled,HIGH);
  delay(yelrand);
  digitalWrite(yelled,LOW);
}

void loop() {
  delay(100);
  digitalWrite(greled, HIGH);

  if (digitalRead(2) == 0) {
    long stoptime = millis();
    long mytime = (stoptime - starttime - 1100 - redrand - yelrand);
    
    // Display reaction time on SSD1306 display with bigger font
    display.clearDisplay();
    display.setTextSize(1); // Set text size to 2 (larger)
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0,0);
    display.print("Your time is:");
    display.setCursor(0,20); // Increase Y position to accommodate larger font
    display.print(mytime);
    display.print(" ms:");
    display.display();

    Serial.print("start - ");
    Serial.println(starttime);
    Serial.print("stop - ");
    Serial.println(stoptime);
    Serial.print("mytime - ");
    Serial.print(mytime);
  }
}