text: /* ESP HTTP Client Example
  
     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 "esp_wifi.h"
  #include "esp_event_loop.h"
  #include "esp_log.h"
  #include "esp_system.h"
  #include "freertos/event_groups.h"
  #include "esp_wifi.h"
  #include "esp_event_loop.h"
  #include "esp_log.h"
  #include "app_wifi.h"
  
  static const char *TAG = "WIFI";
  
  /* FreeRTOS event group to signal when we are connected & ready to make a request */
  static EventGroupHandle_t wifi_event_group;
  
  /* The event group allows multiple bits for each event,
     but we only care about one event - are we connected
     to the AP with an IP? */
  const int CONNECTED_BIT = BIT0;
  
  static esp_err_t event_handler(void *ctx, system_event_t *event)
  {
      switch (event->event_id) {
          case SYSTEM_EVENT_STA_START:
              esp_wifi_connect();
              break;
          case SYSTEM_EVENT_STA_GOT_IP:
              xEventGroupSetBits(wifi_event_group, CONNECTED_BIT);
              break;
          case SYSTEM_EVENT_STA_DISCONNECTED:
              /* This is a workaround as ESP32 WiFi libs don't currently
                 auto-reassociate. */
              esp_wifi_connect();
              xEventGroupClearBits(wifi_event_group, CONNECTED_BIT);
              break;
          default:
              break;
      }
      return ESP_OK;
  }
  
  void app_wifi_initialise(void)
  {
      tcpip_adapter_init();
      wifi_event_group = xEventGroupCreate();
      ESP_ERROR_CHECK(esp_event_loop_init(event_handler, NULL));
      wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
      ESP_ERROR_CHECK(esp_wifi_init(&cfg));
      ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
      wifi_config_t wifi_config = {
          .sta = {
              .ssid = CONFIG_WIFI_SSID,
              .password = CONFIG_WIFI_PASSWORD,
          },
      };
      ESP_LOGI(TAG, "Setting WiFi configuration SSID %s...", wifi_config.sta.ssid);
      ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
      ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config));
      ESP_ERROR_CHECK(esp_wifi_start());
  
  }
  
  void app_wifi_wait_connected()
  {
      xEventGroupWaitBits(wifi_event_group, CONNECTED_BIT, false, true, portMAX_DELAY);
  }
  