#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;
  }
}