xInfo/main/WifiManager.cpp

/**
 * @file WifiManager.cpp
 * @brief Implementation of the WifiManager class.
 */
#include "WifiManager.h"
#include "esp_log.h"
#include "esp_netif.h"
#include "esp_wifi.h"
#include <cstring>

static const char *TAG = "WifiManager";

// Event bits used to signal completion or failure of Wi-Fi connection
#define WIFI_CONNECTED_BIT BIT0
#define WIFI_FAIL_BIT BIT1

WifiManager::WifiManager(const std::string &ssid, const std::string &password)
    : ssid_(ssid), password_(password), wifi_event_group_(nullptr) {}

WifiManager::~WifiManager() {
  // Clean up registered event handlers and destroy the FreeRTOS event group.
  if (wifi_event_group_) {
    esp_event_handler_instance_unregister(IP_EVENT, IP_EVENT_STA_GOT_IP,
                                          instance_got_ip_);
    esp_event_handler_instance_unregister(WIFI_EVENT, ESP_EVENT_ANY_ID,
                                          instance_any_id_);
    vEventGroupDelete(wifi_event_group_);
  }
}

bool WifiManager::connect() {
  // Create an event group to block main execution until connection finishes.
  wifi_event_group_ = xEventGroupCreate();

  // Initialize the underlying TCP/IP stack and default event loop.
  ESP_ERROR_CHECK(esp_netif_init());
  ESP_ERROR_CHECK(esp_event_loop_create_default());
  esp_netif_create_default_wifi_sta();

  // Initialize the Wi-Fi driver with standard configuration values.
  wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
  ESP_ERROR_CHECK(esp_wifi_init(&cfg));

  // Register internal event handlers to process Wi-Fi and IP events.
  ESP_ERROR_CHECK(esp_event_handler_instance_register(
      WIFI_EVENT, ESP_EVENT_ANY_ID, &WifiManager::eventHandler, this,
      &instance_any_id_));
  ESP_ERROR_CHECK(esp_event_handler_instance_register(
      IP_EVENT, IP_EVENT_STA_GOT_IP, &WifiManager::eventHandler, this,
      &instance_got_ip_));

  // Set up the Wi-Fi station configuration structures.
  wifi_config_t wifi_config = {};
  strncpy((char *)wifi_config.sta.ssid, ssid_.c_str(),
          sizeof(wifi_config.sta.ssid) - 1);
  strncpy((char *)wifi_config.sta.password, password_.c_str(),
          sizeof(wifi_config.sta.password) - 1);

  // Set the hardware mode to station mode (client) and commit settings.
  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());

  ESP_LOGI(TAG, "wifi_init_sta finished.");

  // Wait indefinitely until either the connected or failed bit is set.
  EventBits_t bits =
      xEventGroupWaitBits(wifi_event_group_, WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
                          pdFALSE, pdFALSE, portMAX_DELAY);

  // Evaluate the outcome of the connection process.
  if (bits & WIFI_CONNECTED_BIT) {
    ESP_LOGI(TAG, "connected to ap SSID:%s", ssid_.c_str());
    return true;
  } else if (bits & WIFI_FAIL_BIT) {
    ESP_LOGI(TAG, "Failed to connect to SSID:%s", ssid_.c_str());
    return false;
  } else {
    ESP_LOGE(TAG, "UNEXPECTED EVENT");
    return false;
  }
}

void WifiManager::eventHandler(void *arg, esp_event_base_t event_base,
                               int32_t event_id, void *event_data) {
  // Recover the 'this' instance from the void pointer argument.
  WifiManager *instance = static_cast<WifiManager *>(arg);
  if (!instance)
    return;

  // Dispatch the event to the appropriate handlers based on its base type.
  if (event_base == WIFI_EVENT) {
    instance->handleWifiEvent(event_id, event_data);
  } else if (event_base == IP_EVENT) {
    instance->handleIpEvent(event_id, event_data);
  }
}

void WifiManager::handleWifiEvent(int32_t event_id, void *event_data) {
  if (event_id == WIFI_EVENT_STA_START) {
    // When the station has started, immediately kick off a connection.
    esp_wifi_connect();
  } else if (event_id == WIFI_EVENT_STA_DISCONNECTED) {
    // Attempt continuous reconnection, without giving up.
    ESP_LOGI(TAG, "retry to connect to the AP in 3 seconds...");
    vTaskDelay(pdMS_TO_TICKS(3000));
    esp_wifi_connect();
    // Intentionally omit setting WIFI_FAIL_BIT to keep retrying indefinitely,
    // ensuring the application never completely terminates due to network
    // failure.
  }
}

void WifiManager::handleIpEvent(int32_t event_id, void *event_data) {
  if (event_id == IP_EVENT_STA_GOT_IP) {
    // Received a DHCP lease from the AP.
    ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;

    // Convert raw IP address into human-readable string.
    char ip_buf[20];
    sprintf(ip_buf, IPSTR, IP2STR(&event->ip_info.ip));
    ip_addr_ = ip_buf;

    // Retrieve and format the MAC address.
    uint8_t mac[6];
    esp_wifi_get_mac(WIFI_IF_STA, mac);
    char mac_buf[20];
    sprintf(mac_buf, "%02x:%02x:%02x:%02x:%02x:%02x", mac[0], mac[1], mac[2],
            mac[3], mac[4], mac[5]);
    mac_ = mac_buf;

    // Fetch details like RSSI directly from the active AP connection record.
    wifi_ap_record_t ap_info;
    if (esp_wifi_sta_get_ap_info(&ap_info) == ESP_OK) {
      rssi_ = ap_info.rssi;
    }

    // Signal the main task that the connection sequence has successfully
    // completed.
    xEventGroupSetBits(wifi_event_group_, WIFI_CONNECTED_BIT);
  }
}

// Accessor implementations returning internal state strings.
std::string WifiManager::getIp() const { return ip_addr_; }
std::string WifiManager::getMac() const { return mac_; }
std::string WifiManager::getSsid() const { return ssid_; }
int8_t WifiManager::getRssi() const { return rssi_; }