// Include the required libraries
#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

#define SDA_PIN 21
#define SCL_PIN 22

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
// The pins for I2C are defined by the Wire-library. 
// On an arduino UNO:       A4(SDA), A5(SCL)
// On an arduino MEGA 2560: 20(SDA), 21(SCL)
// On an arduino LEONARDO:   2(SDA),  3(SCL), ...
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);



void setup() {
  Serial.begin(9600);

  // For ESP32, we MUST initialize the I2C bus on the correct GPIO pins.
  Wire.begin(SDA_PIN, SCL_PIN);

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }

  // Show initial display buffer contents on the screen --
  // the library initializes this with an Adafruit splash screen.
  display.display();
  delay(2000); // Pause for 2 seconds

 // --- DISPLAY "Hey!!" ---

  display.clearDisplay(); // 1. Clear the screen buffer
  display.setTextSize(3); // 2. Set the text size to a value (3X)
  display.setTextColor(SSD1306_WHITE); // 3. Set the text color
  display.setCursor(20, 20); // 4. Set the starting position (roughly centered)
  display.println(F("Hey!!")); // 5. Print the text to the display's memory buffer

  display.display(); // 6. Push the buffer content from memory to the physical screen!
}

void loop() {
  // We only want to display the message once in setup(), so loop() is empty.
}