text: /*
     This example code is in the Public Domain (or CC0 licensed, at your option.)
  
     Unless required by applicable law or agreed to in writing, this
     software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
     CONDITIONS OF ANY KIND, either express or implied.
  */
  
  #include <stdint.h>
  #include <string.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include "nvs.h"
  #include "nvs_flash.h"
  #include "freertos/FreeRTOS.h"
  #include "freertos/task.h"
  #include "esp_log.h"
  #include "esp_bt.h"
  #include "esp_bt_main.h"
  #include "esp_gap_bt_api.h"
  #include "esp_bt_device.h"
  #include "esp_spp_api.h"
  
  #include "time.h"
  #include "sys/time.h"
  
  #define SPP_TAG "SPP_INITIATOR_DEMO"
  #define EXAMPLE_DEVICE_NAME "ESP_SPP_INITIATOR"
  
  #define SPP_SHOW_DATA 0
  #define SPP_SHOW_SPEED 1
  #define SPP_SHOW_MODE SPP_SHOW_SPEED    /*Choose show mode: show data or speed*/
  
  static const esp_spp_mode_t esp_spp_mode = ESP_SPP_MODE_CB;
  
  static struct timeval time_new, time_old;
  static long data_num = 0;
  
  static const esp_spp_sec_t sec_mask = ESP_SPP_SEC_AUTHENTICATE;
  static const esp_spp_role_t role_master = ESP_SPP_ROLE_MASTER;
  
  static esp_bd_addr_t peer_bd_addr;
  static uint8_t peer_bdname_len;
  static char peer_bdname[ESP_BT_GAP_MAX_BDNAME_LEN + 1];
  static const char remote_device_name[] = "ESP_SPP_ACCEPTOR";
  static const esp_bt_inq_mode_t inq_mode = ESP_BT_INQ_MODE_GENERAL_INQUIRY;
  static const uint8_t inq_len = 30;
  static const uint8_t inq_num_rsps = 0;
  
  #if (SPP_SHOW_MODE == SPP_SHOW_DATA)
  #define SPP_DATA_LEN 20
  #else
  #define SPP_DATA_LEN ESP_SPP_MAX_MTU
  #endif
  static uint8_t spp_data[SPP_DATA_LEN];
  
  static void print_speed(void)
  {
      float time_old_s = time_old.tv_sec + time_old.tv_usec / 1000000.0;
      float time_new_s = time_new.tv_sec + time_new.tv_usec / 1000000.0;
      float time_interval = time_new_s - time_old_s;
      float speed = data_num * 8 / time_interval / 1000.0;
      ESP_LOGI(SPP_TAG, "speed(%fs ~ %fs): %f kbit/s" , time_old_s, time_new_s, speed);
      data_num = 0;
      time_old.tv_sec = time_new.tv_sec;
      time_old.tv_usec = time_new.tv_usec;
  }
  
  static bool get_name_from_eir(uint8_t *eir, char *bdname, uint8_t *bdname_len)
  {
      uint8_t *rmt_bdname = NULL;
      uint8_t rmt_bdname_len = 0;
  
      if (!eir) {
          return false;
      }
  
      rmt_bdname = esp_bt_gap_resolve_eir_data(eir, ESP_BT_EIR_TYPE_CMPL_LOCAL_NAME, &rmt_bdname_len);
      if (!rmt_bdname) {
          rmt_bdname = esp_bt_gap_resolve_eir_data(eir, ESP_BT_EIR_TYPE_SHORT_LOCAL_NAME, &rmt_bdname_len);
      }
  
      if (rmt_bdname) {
          if (rmt_bdname_len > ESP_BT_GAP_MAX_BDNAME_LEN) {
              rmt_bdname_len = ESP_BT_GAP_MAX_BDNAME_LEN;
          }
  
          if (bdname) {
              memcpy(bdname, rmt_bdname, rmt_bdname_len);
              bdname[rmt_bdname_len] = '\0';
          }
          if (bdname_len) {
              *bdname_len = rmt_bdname_len;
          }
          return true;
      }
  
      return false;
  }
  
  static void esp_spp_cb(esp_spp_cb_event_t event, esp_spp_cb_param_t *param)
  {
      switch (event) {
      case ESP_SPP_INIT_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_INIT_EVT");
          esp_bt_dev_set_device_name(EXAMPLE_DEVICE_NAME);
          esp_bt_gap_set_scan_mode(ESP_BT_CONNECTABLE, ESP_BT_GENERAL_DISCOVERABLE);
          esp_bt_gap_start_discovery(inq_mode, inq_len, inq_num_rsps);
  
          break;
      case ESP_SPP_DISCOVERY_COMP_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_DISCOVERY_COMP_EVT status=%d scn_num=%d",param->disc_comp.status, param->disc_comp.scn_num);
          if (param->disc_comp.status == ESP_SPP_SUCCESS) {
              esp_spp_connect(sec_mask, role_master, param->disc_comp.scn[0], peer_bd_addr);
          }
          break;
      case ESP_SPP_OPEN_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_OPEN_EVT");
          esp_spp_write(param->open.handle, SPP_DATA_LEN, spp_data);
          gettimeofday(&time_old, NULL);
          break;
      case ESP_SPP_CLOSE_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_CLOSE_EVT");
          break;
      case ESP_SPP_START_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_START_EVT");
          break;
      case ESP_SPP_CL_INIT_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_CL_INIT_EVT");
          break;
      case ESP_SPP_DATA_IND_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_DATA_IND_EVT");
          break;
      case ESP_SPP_CONG_EVT:
  #if (SPP_SHOW_MODE == SPP_SHOW_DATA)
          ESP_LOGI(SPP_TAG, "ESP_SPP_CONG_EVT cong=%d", param->cong.cong);
  #endif
          if (param->cong.cong == 0) {
              esp_spp_write(param->cong.handle, SPP_DATA_LEN, spp_data);
          }
          break;
      case ESP_SPP_WRITE_EVT:
  #if (SPP_SHOW_MODE == SPP_SHOW_DATA)
          ESP_LOGI(SPP_TAG, "ESP_SPP_WRITE_EVT len=%d cong=%d", param->write.len , param->write.cong);
          esp_log_buffer_hex("",spp_data,SPP_DATA_LEN);
  #else
          gettimeofday(&time_new, NULL);
          data_num += param->write.len;
          if (time_new.tv_sec - time_old.tv_sec >= 3) {
              print_speed();
          }
  #endif
          if (param->write.cong == 0) {
              esp_spp_write(param->write.handle, SPP_DATA_LEN, spp_data);
          }
          break;
      case ESP_SPP_SRV_OPEN_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_SRV_OPEN_EVT");
          break;
      case ESP_SPP_UNINIT_EVT:
          ESP_LOGI(SPP_TAG, "ESP_SPP_UNINIT_EVT");
          break;
      default:
          break;
      }
  }
  
  static void esp_bt_gap_cb(esp_bt_gap_cb_event_t event, esp_bt_gap_cb_param_t *param)
  {
      switch(event){
      case ESP_BT_GAP_DISC_RES_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_DISC_RES_EVT");
          esp_log_buffer_hex(SPP_TAG, param->disc_res.bda, ESP_BD_ADDR_LEN);
          for (int i = 0; i < param->disc_res.num_prop; i++){
              if (param->disc_res.prop[i].type == ESP_BT_GAP_DEV_PROP_EIR
                  && get_name_from_eir(param->disc_res.prop[i].val, peer_bdname, &peer_bdname_len)){
                  esp_log_buffer_char(SPP_TAG, peer_bdname, peer_bdname_len);
                  if (strlen(remote_device_name) == peer_bdname_len
                      && strncmp(peer_bdname, remote_device_name, peer_bdname_len) == 0) {
                      memcpy(peer_bd_addr, param->disc_res.bda, ESP_BD_ADDR_LEN);
                      esp_spp_start_discovery(peer_bd_addr);
                      esp_bt_gap_cancel_discovery();
                  }
              }
          }
          break;
      case ESP_BT_GAP_DISC_STATE_CHANGED_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_DISC_STATE_CHANGED_EVT");
          break;
      case ESP_BT_GAP_RMT_SRVCS_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_RMT_SRVCS_EVT");
          break;
      case ESP_BT_GAP_RMT_SRVC_REC_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_RMT_SRVC_REC_EVT");
          break;
      case ESP_BT_GAP_AUTH_CMPL_EVT:{
          if (param->auth_cmpl.stat == ESP_BT_STATUS_SUCCESS) {
              ESP_LOGI(SPP_TAG, "authentication success: %s", param->auth_cmpl.device_name);
              esp_log_buffer_hex(SPP_TAG, param->auth_cmpl.bda, ESP_BD_ADDR_LEN);
          } else {
              ESP_LOGE(SPP_TAG, "authentication failed, status:%d", param->auth_cmpl.stat);
          }
          break;
      }
      case ESP_BT_GAP_PIN_REQ_EVT:{
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_PIN_REQ_EVT min_16_digit:%d", param->pin_req.min_16_digit);
          if (param->pin_req.min_16_digit) {
              ESP_LOGI(SPP_TAG, "Input pin code: 0000 0000 0000 0000");
              esp_bt_pin_code_t pin_code = {0};
              esp_bt_gap_pin_reply(param->pin_req.bda, true, 16, pin_code);
          } else {
              ESP_LOGI(SPP_TAG, "Input pin code: 1234");
              esp_bt_pin_code_t pin_code;
              pin_code[0] = '1';
              pin_code[1] = '2';
              pin_code[2] = '3';
              pin_code[3] = '4';
              esp_bt_gap_pin_reply(param->pin_req.bda, true, 4, pin_code);
          }
          break;
      }
  
  #if (CONFIG_BT_SSP_ENABLED == true)
      case ESP_BT_GAP_CFM_REQ_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_CFM_REQ_EVT Please compare the numeric value: %d", param->cfm_req.num_val);
          esp_bt_gap_ssp_confirm_reply(param->cfm_req.bda, true);
          break;
      case ESP_BT_GAP_KEY_NOTIF_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_KEY_NOTIF_EVT passkey:%d", param->key_notif.passkey);
          break;
      case ESP_BT_GAP_KEY_REQ_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_KEY_REQ_EVT Please enter passkey!");
          break;
  #endif
  
      case ESP_BT_GAP_MODE_CHG_EVT:
          ESP_LOGI(SPP_TAG, "ESP_BT_GAP_MODE_CHG_EVT mode:%d", param->mode_chg.mode);
          break;
  
      default:
          break;
      }
  }
  
  void app_main(void)
  {
      for (int i = 0; i < SPP_DATA_LEN; ++i) {
          spp_data[i] = i;
      }
  
      esp_err_t ret = nvs_flash_init();
      if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
          ESP_ERROR_CHECK(nvs_flash_erase());
          ret = nvs_flash_init();
      }
      ESP_ERROR_CHECK( ret );
  
      ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_BLE));
  
      esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
      if ((ret = esp_bt_controller_init(&bt_cfg)) != ESP_OK) {
          ESP_LOGE(SPP_TAG, "%s initialize controller failed: %s\n", __func__, esp_err_to_name(ret));
          return;
      }
  
      if ((ret = esp_bt_controller_enable(ESP_BT_MODE_CLASSIC_BT)) != ESP_OK) {
          ESP_LOGE(SPP_TAG, "%s enable controller failed: %s\n", __func__, esp_err_to_name(ret));
          return;
      }
  
      if ((ret = esp_bluedroid_init()) != ESP_OK) {
          ESP_LOGE(SPP_TAG, "%s initialize bluedroid failed: %s\n", __func__, esp_err_to_name(ret));
          return;
      }
  
      if ((ret = esp_bluedroid_enable()) != ESP_OK) {
          ESP_LOGE(SPP_TAG, "%s enable bluedroid failed: %s\n", __func__, esp_err_to_name(ret));
          return;
      }
  
      if ((ret = esp_bt_gap_register_callback(esp_bt_gap_cb)) != ESP_OK) {
          ESP_LOGE(SPP_TAG, "%s gap register failed: %s\n", __func__, esp_err_to_name(ret));
          return;
      }
  
      if ((ret = esp_spp_register_callback(esp_spp_cb)) != ESP_OK) {
          ESP_LOGE(SPP_TAG, "%s spp register failed: %s\n", __func__, esp_err_to_name(ret));
          return;
      }
  
      if ((ret = esp_spp_init(esp_spp_mode)) != ESP_OK) {
          ESP_LOGE(SPP_TAG, "%s spp init failed: %s\n", __func__, esp_err_to_name(ret));
          return;
      }
  
  #if (CONFIG_BT_SSP_ENABLED == true)
      /* Set default parameters for Secure Simple Pairing */
      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));
  #endif
  
      /*
       * Set default parameters for Legacy Pairing
       * Use variable pin, input pin code when pairing
       */
      esp_bt_pin_type_t pin_type = ESP_BT_PIN_TYPE_VARIABLE;
      esp_bt_pin_code_t pin_code;
      esp_bt_gap_set_pin(pin_type, 0, pin_code);
  }
  
  