bt with NAME - 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_DEVICE_NAME "YourDeviceName" // Replace with actual Bluetooth device name

static esp_bd_addr_t target_bd_addr;
static bool paired = false;
static bool connected = false;
static uint32_t spp_handle = 0; // Store SPP session handle

// GAP callback function (handles pairing, discovery, 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_DISC_RES_EVT: {
            Serial.println("Device discovered.");
            for (int i = 0; i < param->disc_res.num_prop; i++) {
                if (param->disc_res.prop[i].type == ESP_BT_GAP_DEV_PROP_BDNAME) {
                    char *device_name = (char *)param->disc_res.prop[i].val;
                    Serial.print("Found device: ");
                    Serial.println(device_name);

                    if (strcmp(device_name, TARGET_DEVICE_NAME) == 0) {
                        memcpy(target_bd_addr, param->disc_res.bda, sizeof(esp_bd_addr_t));
                        Serial.println("Target device found! Connecting...");
                        esp_spp_connect(ESP_SPP_SEC_AUTHENTICATE, ESP_SPP_ROLE_MASTER, 1, target_bd_addr);
                        esp_bt_gap_cancel_discovery(); // Stop discovery once found
                    }
                }
            }
            break;
        }

        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;

        default:
            break;
    }
}

// SPP callback function (handles connection status and data reception)
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);

            // Enable Secure Simple Pairing (SSP)
            esp_bt_sp_param_t param_type = ESP_BT_SP_IOCAP_MODE;
            esp_bt_io_cap_t iocap = ESP_BT_IO_CAP_IO;
            esp_bt_gap_set_security_param(param_type, &iocap, sizeof(uint8_t));

            // Start discovery and attempt connection
            esp_bt_gap_start_discovery(ESP_BT_INQ_MODE_GENERAL_INQUIRY, 10, 0);
            break;

        case ESP_SPP_OPEN_EVT:
            Serial.println("SPP connection established!");
            connected = true;
            spp_handle = param->open.handle; // Store session handle for data transfer
            break;

        case ESP_SPP_CLOSE_EVT:
            Serial.println("SPP connection closed.");
            connected = false;
            spp_handle = 0;
            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);
}

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

void loop() {
    if (connected) {
        Serial.println("Connected to Bluetooth device. Waiting for data...");
        uint8_t buffer[128];
        int len = esp_spp_read(spp_handle, buffer, sizeof(buffer));
        if (len > 0) {
            Serial.print("Received Data: ");
            for (int i = 0; i < len; i++) {
                Serial.write(buffer[i]);
            }
            Serial.println();
        }
    } else if (paired) {
        Serial.println("Paired but not connected.");
    } else {
        Serial.println("Waiting for pairing...");
    }
    delay(5000);
}