#define PROFILE_NUM 1
#define PROFILE_APP_IDX 0

#define LED_CHAR_UUID 0x0100
#define LED_CHAR_PROP (ESP_GATT_CHAR_PROP_BIT_WRITE | ESP_GATT_CHAR_PROP_BIT_READ)
#define LED_CHAR_DESCR_UUID 0x0101
#define LED_SERVICE_UUID 0x00FF
#define LED_VALUE_LEN 1

static uint8_t led_value = 0;

static uint8_t led_char_descr[ESP_UUID_LEN_16] = {
    ESP_UUID_16(LED_CHAR_DESCR_UUID),
    ESP_UUID_16(ESP_GATT_UUID_CHAR_CLIENT_CONFIG),
};

static esp_ble_adv_data_t adv_data = {
    .set_scan_rsp = false,
    .include_name = true,
    .include_txpower = true,
    .min_interval = 0x20,
    .max_interval = 0x40,
    .appearance = 0x00,
    .manufacturer_len = 0,
    .p_manufacturer_data = NULL,
    .service_data_len = 0,
    .p_service_data = NULL,
    .service_uuid_len = sizeof(LED_SERVICE_UUID),
    .p_service_uuid = (uint8_t *)&LED_SERVICE_UUID,
    .flag = (ESP_BLE_ADV_FLAG_GEN_DISC | ESP_BLE_ADV_FLAG_BREDR_NOT_SPT),
};

static esp_ble_adv_params_t adv_params = {
    .adv_int_min = 0x20,
    .adv_int_max = 0x40,
    .adv_type = ADV_TYPE_NONCONN_IND,
    .own_addr_type = BLE_ADDR_TYPE_PUBLIC,
    .channel_map = ADV_CHNL_ALL,
    .adv_filter_policy = ADV_FILTER_ALLOW_SCAN_ANY_CON_ANY,
};

static esp_gatts_attr_db_t gatt_db[1] = {
    [0] = {
        .att_desc = {
            .uuid_length = ESP_UUID_LEN_16,
            .uuid_p = (uint8_t *)&LED_CHAR_UUID,
            .perm = ESP_GATT_PERM_READ | ESP_GATT_PERM_WRITE,
            .max_length = LED_VALUE_LEN,
            .length = LED_VALUE_LEN,
        },
        .desc = {
            .uuid_length = ESP_UUID_LEN_16,
            .uuid_p = (uint8_t *)&LED_CHAR_DESCR_UUID,
            .perm = ESP_GATT_PERM_READ | ESP_GATT_PERM_WRITE,
            .max_length = sizeof(uint16_t),
            .length = sizeof(uint16_t),
            .value = (uint8_t *)&led_char_descr,
        },
        .attr_control = {
            .auto_rsp = ESP_GATT_AUTO_RSP,
        },
    },
};

static esp_gatts_attr_db_t *gatt_db_ptr = gatt_db;

static esp_gatts_service_t gatt_service = {
    .uuid = {
        .len = ESP_UUID_LEN_16,
        .uuid = (uint8_t *)&LED_SERVICE_UUID,
    },
    .num_handle = 1,
    .handle = NULL,
    .end_handle = NULL,
    .type = ESP_GATT_SVC_TYPE_PRIMARY,
    .parent = NULL,
    .desc = {
        .uuid_length = 0,
        .uuid_p = NULL,
        .perm = 0,
        .max_length = 0,
        .length = 0,
        .value = NULL,
    },
    .srvc_db = gatt
static void gatts_event_handler(esp_gatts_cb_event_t event, esp_gatt_if_t gatts_if, esp_ble_gatts_cb_param_t *param)
{
    switch (event) {
        case ESP_GATTS_REG_EVT:
            esp_ble_gap_set_device_name("LED Control");
            esp_ble_gap_config_adv_data(&adv_data);
            esp_ble_gatts_create_service(gatts_if, &gatt_service, PROFILE_NUM);
            break;
        case ESP_GATTS_READ_EVT:
            if (param->read.handle == gatt_db[0].att_desc.handle) {
                esp_ble_gatts_send_response(gatts_if, param->read.conn_id, param->read.trans_id, ESP_GATT_OK, &led_value, sizeof(led_value));
            }
            break;
        case ESP_GATTS_WRITE_EVT:
            if (param->write.handle == gatt_db[0].att_desc.handle) {
                led_value = *param->write.value;
                update_led_brightness(led_value);
                esp_ble_gatts_send_response(gatts_if, param->write.conn_id, param->write.trans_id, ESP_GATT_OK, NULL, 0);
            }
            break;
        case ESP_GATTS_CREAT_ATTR_TAB_EVT:
            if (param->add_attr_tab.status != ESP_GATT_OK) {
                break;
            }
            gatt_db_ptr[0].att_desc.handle = param->add_attr_tab.handles[0];
            gatt_db_ptr[0].desc.handle = param->add_attr_tab.handles[1];
            esp_ble_gatts_start_service(gatt_db_ptr[0].att_desc.handle);
            break;
        case ESP_GATTS_CONNECT_EVT:
            esp_ble_gap_stop_advertising();
            break;
        case ESP_GATTS_DISCONNECT_EVT:
            esp_ble_gap_start_advertising(&adv_params);
            break;
        default:
            break;
    }
}

void app_main()
{
    gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);
    gpio_set_direction(BUTTON_A_PIN, GPIO_MODE_INPUT);
    gpio_set_direction(BUTTON_B_PIN, GPIO_MODE_INPUT);
    gpio_set_direction(BUTTON_C_PIN, GPIO_MODE_INPUT);

    esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
    esp_bt_controller_init(&bt_cfg);
    esp_bt_controller_enable(ESP_BT_MODE_BLE);

    esp
    esp_bluedroid_init();
    esp_bluedroid_enable();
    esp_gap_ble_set_device_name("LED Control");
    esp_gap_ble_set_advertise_mode(ESP_BLE_ADV_TYPE_ADV_IND);
    esp_gap_ble_add_service_uuid(&gatt_service_id);
    esp_gap_ble_set_adv_data(&adv_data);
    esp_gap_ble_start_advertising(&adv_params);

    esp_ble_gatts_register_callback(gatts_event_handler);
    esp_ble_gatts_app_register(PROFILE_NUM);

    while (1) {
        if (gpio_get_level(BUTTON_A_PIN) == 0) {
            increase_led_brightness();
        }
        if (gpio_get_level(BUTTON_B_PIN) == 0) {
            decrease_led_brightness();
        }
        if (gpio_get_level(BUTTON_C_PIN) == 0) {
            toggle_led();
        }
        vTaskDelay(50 / portTICK_PERIOD_MS);
    }
}