esp32/domestic-climate-monitor/main/wifi.c

#include "esp_event.h"
#include "esp_log.h"
#include "esp_wifi.h"
#include "freertos/task.h"
#include "secrets.h"

static const char *TAG = "wifi"; // Logs are coming from this wifi module
static uint32_t WIFI_CONNECTED = 0;

static int s_retry_num = 0;

#define MAX_RETRY 5

static void wifi_event_handler(void *arg, esp_event_base_t event_base,
                               int32_t event_id, void *event_data)
{

  if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START)
  {
    esp_wifi_connect();
  }

  if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED)
  {
    if (s_retry_num < MAX_RETRY)
    {
      esp_wifi_connect();
      s_retry_num++;
      ESP_LOGI(TAG, "Trying to reconnect to WiFi.");
    }
    else
    {
      ESP_LOGI(TAG, "Could not connect to WiFi. Giving up.");
    }
  }

  if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP)
  {
    s_retry_num = 0;
    WIFI_CONNECTED = 1;
  }
}

void wifi_connect(void)
{

  ESP_LOGI(TAG, "Attempting to connect to WiFi");

  // Initialise network interface layer (Internet Layer) once Link Layer
  // established (in standard TCP/IP architecture)
  ESP_ERROR_CHECK(esp_netif_init());

  // Create default event dispatcher
  ESP_ERROR_CHECK(esp_event_loop_create_default());

  // Having established interface layer, create an interface instance
  esp_netif_create_default_wifi_sta();

  // Initialise WiFi driver (Link Layer)
  wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();

  ESP_ERROR_CHECK(esp_wifi_init(&cfg));

  ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID,
                                             &wifi_event_handler, NULL));
  ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, ESP_EVENT_ANY_ID,
                                             &wifi_event_handler, NULL));

  wifi_config_t wifi_config = {
      .sta =
          {
              .ssid = SECRETS_WIFI_SSID,
              .password = SECRETS_WIFI_PASS,
          },
  };

  // Set WiFi mode to 'station' (basically a client connecting to a WiFi access
  // point)
  ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));

  // Give connection config to WiFi driver
  ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));

  // Begin the connection which triggers WIFI_EVENT_STA_START (the event which
  // is the basis for the actual connection defined in the event handler)
  ESP_ERROR_CHECK(esp_wifi_start());

  // Block main execution until WiFi connection est

  ESP_LOGI(TAG, "Waiting for WiFi connection...");

  while (!WIFI_CONNECTED)
  {
    vTaskDelay(pdMS_TO_TICKS(100));
  }
}