#include "ntp.h"

#include <string.h>
#include <sys/time.h>
#include <time.h>
#include "esp_attr.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_netif_sntp.h"
#include "esp_sleep.h"
#include "esp_sntp.h"
#include "esp_system.h"
#include "lwip/ip_addr.h"
#include "nvs_flash.h"

#include "sdkconfig.h"

static const char* TAG = "NTP";

void obtain_time(void) {
  ESP_LOGI(TAG, "Initializing SNTP");

  esp_sntp_config_t config =
      ESP_NETIF_SNTP_DEFAULT_CONFIG(CONFIG_SNTP_TIME_SERVER);
  config.start = false;
  config.server_from_dhcp = true;
  config.renew_servers_after_new_IP = true;
  config.index_of_first_server = 1;
  config.ip_event_to_renew = IP_EVENT_STA_GOT_IP;
  esp_netif_sntp_init(&config);

  ESP_LOGI(TAG, "Starting SNTP");
  esp_netif_sntp_start();

  // wait for time to be set
  time_t now = 0;
  struct tm timeinfo = {0};
  int retry = 0;
  const int retry_count = 15;
  while (esp_netif_sntp_sync_wait(2000 / portTICK_PERIOD_MS) ==
             ESP_ERR_TIMEOUT &&
         ++retry < retry_count) {
    ESP_LOGI(TAG, "Waiting for system time to be set... (%d/%d)", retry,
             retry_count);
  }
  time(&now);
  localtime_r(&now, &timeinfo);

  esp_netif_sntp_deinit();
}

esp_err_t init_ntp(void) {
  time_t now;
  struct tm timeinfo;
  time(&now);
  localtime_r(&now, &timeinfo);

  if (timeinfo.tm_year < (2016 - 1900)) {
    ESP_LOGI(
        TAG,
        "Time is not set yet. Connecting to WiFi and getting time over NTP.");
    obtain_time();
  }

  char strftime_buf[64];

  // Set timezone to Eastern Standard Time and print local time
  setenv("TZ", "CET-1CEST,M3.5.0,M10.5.0/3", 1);
  tzset();
  time(&now);
  localtime_r(&now, &timeinfo);
  strftime(strftime_buf, sizeof(strftime_buf), "%c", &timeinfo);
  ESP_LOGI(TAG, "The current date/time in Berlin/Europe is: %s", strftime_buf);

  return ESP_OK;
}