1 files changed, 93 insertions, 0 deletions
diff --git a/src/wifi.c b/src/wifi.c
new file mode 100644
index 0000000..593cf72
--- /dev/null
+++ b/src/wifi.c
@@ -0,0 +1,93 @@
+#include "esp_log.h"
+#include "esp_wifi.h"
+#include "freertos/event_groups.h"
+#include "nvs_flash.h"
+
+/* FreeRTOS event group to signal when we are connected*/
+static EventGroupHandle_t s_wifi_event_group;
+
+/* The event group allows multiple bits for each event, but we only care about
+ * two events:
+ * - we are connected to the AP with an IP
+ * - we failed to connect after the maximum amount of retries */
+#define WIFI_CONNECTED_BIT BIT0
+#define WIFI_FAIL_BIT BIT1
+
+static const char *TAG = "wifi";
+
+static int s_retry_num = 0;
+static int s_retry_max = 0;
+
+static void 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();
+  } else if (event_base == WIFI_EVENT &&
+             event_id == WIFI_EVENT_STA_DISCONNECTED) {
+    if (s_retry_num < s_retry_max) {
+      esp_wifi_connect();
+      s_retry_num++;
+      ESP_LOGI(TAG, "retry to connect to the AP");
+    } else {
+      xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
+    }
+    ESP_LOGI(TAG, "connect to the AP fail");
+  } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
+    ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
+    ESP_LOGI(TAG, "IP:" IPSTR, IP2STR(&event->ip_info.ip));
+    s_retry_num = 0;
+    xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
+  }
+}
+
+esp_err_t _wifi_deinit(void) { return esp_wifi_stop(); }
+
+esp_err_t wifi_init(wifi_sta_config_t const *sta_config, uint8_t retries) {
+  esp_event_handler_instance_t instance_any_id;
+  esp_event_handler_instance_t instance_got_ip;
+  wifi_config_t wifi_config = {.sta = *sta_config};
+
+  s_retry_max = retries;
+
+  ESP_ERROR_CHECK(nvs_flash_init());
+  ESP_ERROR_CHECK(esp_netif_init());
+
+  ESP_LOGI(TAG, "SSID: '%s'", sta_config->ssid);
+  ESP_LOGI(TAG, "PASS: '%s'", sta_config->password);
+
+  s_wifi_event_group = xEventGroupCreate();
+  ESP_ERROR_CHECK(esp_event_loop_create_default());
+
+  esp_netif_create_default_wifi_sta();
+  wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+  ESP_ERROR_CHECK(esp_wifi_init(&cfg));
+
+  ESP_ERROR_CHECK(esp_event_handler_instance_register(
+      WIFI_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL, &instance_any_id));
+  ESP_ERROR_CHECK(esp_event_handler_instance_register(
+      IP_EVENT, IP_EVENT_STA_GOT_IP, &event_handler, NULL, &instance_got_ip));
+
+  ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
+  ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
+  ESP_ERROR_CHECK(esp_wifi_start());
+
+  /* Waiting until either the connection is established (WIFI_CONNECTED_BIT) or
+   * connection failed for the maximum number of re-tries (WIFI_FAIL_BIT). The
+   * bits are set by event_handler() (see above) */
+  EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
+                                         WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
+                                         pdFALSE, pdFALSE, portMAX_DELAY);
+
+  /* xEventGroupWaitBits() returns the bits before the call returned, hence we
+   * can test which event actually happened. */
+  if (bits & WIFI_CONNECTED_BIT) {
+    ESP_LOGI(TAG, "CONNECTED");
+    return ESP_OK;
+  } else if (bits & WIFI_FAIL_BIT) {
+    ESP_LOGI(TAG, "FAIL TO CONNECT");
+    return ESP_FAIL;
+  } else {
+    ESP_LOGE(TAG, "UNEXPECTED EVENT");
+    return ESP_FAIL;
+  }
+}