bt with mac address - WITH ssp

#include <Arduino.h>
#include "esp_bt.h"
#include "esp_bt_main.h"
#include "esp_gap_bt_api.h"
#include "esp_spp_api.h"
#include "esp_bt_device.h"
#include "esp_err.h"

#define TARGET_MAC_ADDRESS "XX:XX:XX:XX:XX:XX" // Set the MAC address of your target device
#define BT_PIN_CODE "1234" // Change this to your correct PIN

static esp_bd_addr_t target_bd_addr;
static bool paired = false;
static bool connected = false;

// Convert MAC address string to esp_bd_addr_t format
void str2bda(const char *str, esp_bd_addr_t bda) {
    int values[6];
    if (sscanf(str, "%x:%x:%x:%x:%x:%x", &values[0], &values[1], &values[2], &values[3], &values[4], &values[5]) == 6) {
        for (int i = 0; i < 6; ++i) {
            bda[i] = (uint8_t)values[i];
        }
    }
}

// GAP callback function (handles pairing and authentication)
void bt_gap_callback(esp_bt_gap_cb_event_t event, esp_bt_gap_cb_param_t *param) {
    switch (event) {
        case ESP_BT_GAP_AUTH_CMPL_EVT:
            if (param->auth_cmpl.stat == ESP_BT_STATUS_SUCCESS) {
                Serial.println("Bluetooth pairing successful!");
                paired = true;
            } else {
                Serial.println("Bluetooth pairing failed!");
            }
            break;

        case ESP_BT_GAP_PIN_REQ_EVT:
            Serial.println("PIN requested...");
            esp_bt_gap_pin_reply(param->pin_req.bda, true, strlen(BT_PIN_CODE), (uint8_t *)BT_PIN_CODE);
            Serial.println("PIN sent.");
            break;

        default:
            break;
    }
}

// SPP callback function (handles connection status)
void bt_spp_callback(esp_spp_cb_event_t event, esp_spp_cb_param_t *param) {
    switch (event) {
        case ESP_SPP_INIT_EVT:
            Serial.println("SPP initialized.");
            esp_bt_dev_set_device_name("ESP32_BT_Client");
            esp_bt_gap_register_callback(bt_gap_callback);

            // Disable Secure Simple Pairing (SSP) and use PIN
            esp_bt_pin_type_t pin_type = ESP_BT_PIN_TYPE_FIXED;
            esp_bt_gap_set_pin(pin_type, 4, (uint8_t*)BT_PIN_CODE);

            // Start discovery and attempt connection
            esp_spp_start_discovery(target_bd_addr);
            break;

        case ESP_SPP_DISCOVERY_COMP_EVT:
            if (param->disc_comp.status == ESP_SPP_SUCCESS) {
                Serial.println("Device discovered, attempting connection...");
                esp_spp_connect(ESP_SPP_SEC_AUTHENTICATE, ESP_SPP_ROLE_MASTER, param->disc_comp.scn[0], target_bd_addr);
            } else {
                Serial.println("Device discovery failed.");
            }
            break;

        case ESP_SPP_OPEN_EVT:
            Serial.println("SPP connection established!");
            connected = true;
            break;

        case ESP_SPP_CLOSE_EVT:
            Serial.println("SPP connection closed.");
            connected = false;
            break;

        default:
            break;
    }
}

// Function to initialize Bluetooth
void setup_bluetooth() {
    if (!btStart()) {
        Serial.println("Failed to initialize Bluetooth.");
        return;
    }

    if (esp_bluedroid_init() != ESP_OK) {
        Serial.println("Failed to initialize bluedroid.");
        return;
    }

    if (esp_bluedroid_enable() != ESP_OK) {
        Serial.println("Failed to enable bluedroid.");
        return;
    }

    Serial.println("Bluetooth initialized.");

    esp_spp_register_callback(bt_spp_callback);
    esp_spp_init(ESP_SPP_MODE_CB);

    str2bda(TARGET_MAC_ADDRESS, target_bd_addr);
}

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

void loop() {
    if (connected) {
        Serial.println("Connected to Bluetooth device.");
    } else if (paired) {
        Serial.println("Paired but not connected.");
    } else {
        Serial.println("Waiting for pairing...");
    }
    delay(5000);
}