//
// Created by erki on 25/01/24.
//

#include "clock_core.hpp"

#include "esp_expected.hpp"

#include <cstring>
#include <ctime>

#include <esp_event.h>
#include <esp_log.h>
#include <esp_netif.h>
#include <esp_netif_sntp.h>
#include <esp_wifi.h>

namespace
{

const char* TAG = "clock_core";

constexpr EventBits_t WIFI_FAIL_BIT = BIT0;
constexpr EventBits_t WIFI_CONNECTED_BIT = BIT1;
constexpr EventBits_t SNTP_SYNCED_BIT = BIT2;
constexpr EventBits_t CLOCK_UPDATE_BIT = BIT3;
EventGroupHandle_t clock_core_event_group_;

void wifiEventHandler(void* arg, esp_event_base_t event_base,
                      int32_t event_id, void* event_data)
{
  static int retry_num = 0;

  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 (retry_num < 10)
    {
      esp_wifi_connect();
      retry_num++;
      ESP_LOGI(TAG, "Retrying to connect to AP.");
    }
    else
    {
      xEventGroupSetBits(clock_core_event_group_, WIFI_FAIL_BIT);
    }
    ESP_LOGW(TAG, "Connection to AP failed.");
  }
  else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP)
  {
    auto* event = static_cast<ip_event_got_ip_t*>(event_data);
    ESP_LOGI(TAG, "Connected to AP. Got IP: " IPSTR, IP2STR(&event->ip_info.ip));
    retry_num = 0;

    xEventGroupSetBits(clock_core_event_group_, WIFI_CONNECTED_BIT);
  }
}

void sntpEventHandler(struct timeval*)
{
  xEventGroupSetBits(clock_core_event_group_, SNTP_SYNCED_BIT);
}

void timerEventHandler(TimerHandle_t)
{
  xEventGroupSetBits(clock_core_event_group_, CLOCK_UPDATE_BIT);
}

esp_err_t sntpInitialize()
{
  esp_sntp_config_t config = ESP_NETIF_SNTP_DEFAULT_CONFIG("pool.ntp.org");
  config.smooth_sync = true;
  config.server_from_dhcp = true;
  config.renew_servers_after_new_IP = true;
  config.sync_cb = sntpEventHandler;
  config.start = false;
  config.ip_event_to_renew = IP_EVENT_STA_GOT_IP;

  return esp_netif_sntp_init(&config);
}

std::expected<void, esp_err_t> wifiInitialize(const char* wifi_ssid, const char* wifi_password)
{
  TRY_ESP(esp_netif_init());
  TRY_ESP(esp_event_loop_create_default());
  esp_netif_create_default_wifi_sta();

  wifi_init_config_t config = WIFI_INIT_CONFIG_DEFAULT();
  TRY_ESP(esp_wifi_init(&config));

  TRY_ESP(sntpInitialize());

  esp_event_handler_instance_t instance_any_id;
  esp_event_handler_instance_t instance_got_ip;
  TRY_ESP(esp_event_handler_instance_register(WIFI_EVENT,
                                              ESP_EVENT_ANY_ID,
                                              &wifiEventHandler,
                                              nullptr,
                                              &instance_any_id));
  TRY_ESP(esp_event_handler_instance_register(IP_EVENT,
                                              IP_EVENT_STA_GOT_IP,
                                              &wifiEventHandler,
                                              nullptr,
                                              &instance_got_ip));

  wifi_sta_config_t sta_config;
  std::memset(&sta_config, 0, sizeof(sta_config));
  std::strncpy((char*) sta_config.ssid, wifi_ssid, 32);
  std::strncpy((char*) sta_config.password, wifi_password, 64);
  sta_config.threshold.authmode = WIFI_AUTH_WPA2_PSK;

  wifi_config_t wifi_config = { .sta = sta_config };

  TRY_ESP(esp_wifi_set_mode(WIFI_MODE_STA));
  TRY_ESP(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
  TRY_ESP(esp_wifi_start());

  return {};
}

}

namespace clock_core
{

void run(const char* wifi_ssid, const char* wifi_password)
{
  clock_core_event_group_ = xEventGroupCreate();
  auto clock_timer = xTimerCreate("clock_core",
                                  pdMS_TO_TICKS(60'000),
                                  pdTRUE,
                                  nullptr,
                                  timerEventHandler);

  if (const auto res = wifiInitialize(wifi_ssid, wifi_password);
      !res.has_value())
  {
    ESP_LOGI(TAG, "WiFi setup errored in clock_core::run. Error: %s", esp_err_to_name(res.error()));
    abort();
  }

  while (true)
  {
    const EventBits_t bits = xEventGroupWaitBits(clock_core_event_group_,
                                                 WIFI_CONNECTED_BIT | WIFI_FAIL_BIT | SNTP_SYNCED_BIT | CLOCK_UPDATE_BIT,
                                                 pdTRUE,
                                                 pdFALSE,
                                                 portMAX_DELAY);

    if (bits & WIFI_CONNECTED_BIT)
    {
      ESP_LOGI(TAG, "WiFi setup in clock_core::run successful.");
      if (const auto res = esp_netif_sntp_start();
          res != ESP_OK)
      {
        ESP_LOGE(TAG, "SNTP setup failed. Error: %s", esp_err_to_name(res));
        abort();
      }

      xTimerStart(clock_timer, pdMS_TO_TICKS(10));
    }
    else if (bits & WIFI_FAIL_BIT)
    {
      ESP_LOGE(TAG, "WiFi setup in clock_core::run failed.");
    }
    else if (bits & SNTP_SYNCED_BIT)
    {
      ESP_LOGI(TAG, "SNTP sync successful.");
    }
    else if (bits & CLOCK_UPDATE_BIT)
    {
      char time_buf[64];
      std::time_t time_now;
      std::tm time_info{};
      std::time(&time_now);
      localtime_r(&time_now, &time_info);

      std::strftime(time_buf, sizeof(time_buf), "%c", &time_info);
      ESP_LOGI(TAG, "Current time: %s", time_buf);
    }
    else
    {
      ESP_LOGE(TAG, "WiFi setup encountered an unexpected set of bits. %lu", bits);
    }
  }
}

}