#include <BluetoothSerial.h>
#include <WiFi.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1

BluetoothSerial SerialBT;
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Replace with the actual MAC address of Device 1
uint8_t serverMacAddress[] = {0x24, 0x0A, 0xC4, 0xXX, 0xXX, 0xXX}; // Update this

void setup() {
  Serial.begin(115200);
  
  // Start Bluetooth with the name "ESP32_Device2"
  if (!SerialBT.begin("ESP32_Device2")) {
    Serial.println("An error occurred while starting Bluetooth.");
    while (1); // Halt if Bluetooth fails to start
  }

  Serial.println("Device 2 Bluetooth Started.");

  // Initialize the OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // I2C address 0x3C
    Serial.println(F("SSD1306 allocation failed"));
    while (1); // Halt if display initialization fails
  }
  
  display.clearDisplay(); // Clear the buffer
  display.setTextSize(1); // Set text size to 1
  display.setTextColor(WHITE); // Set text color to white
  display.setCursor(0, 0); // Set the cursor to top-left corner
  display.println("Connecting to Device 1...");
  display.display(); // Display the text

  // Try to connect to Device 1 via MAC address
  while (!SerialBT.connect(serverMacAddress)) {
    Serial.println("Device 2: Connecting...");
    delay(1000); // Wait for 1 second before retrying
  }
  
  Serial.println("Device 2 Connected to Device 1");

  // Update OLED display after successful connection
  display.clearDisplay();
  display.setCursor(0, 0);
  display.println("Connected to Device 1");
  display.display();
}

void loop() {
  if (SerialBT.connected()) {
    // Send a message to Device 1
    String message = "Hello from Device 2";
    SerialBT.println(message);
    Serial.println("Device 2 Sent: " + message);

    // Check for incoming data from Device 1
    if (SerialBT.available()) {
      String receivedData = SerialBT.readString();
      Serial.println("Device 2 Received: " + receivedData);

      // Display the received data on the OLED
      display.clearDisplay();
      display.setCursor(0, 0);
      display.println("Received:");
      display.setCursor(0, 10);
      display.println(receivedData);
      display.display();
    }

    delay(2000); // Send message every 2 seconds
  }

  delay(20); // Small delay for stability
}