package de.ph87.data.weather;

import lombok.NonNull;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.context.event.ApplicationStartedEvent;
import org.springframework.context.event.EventListener;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;
import tools.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.time.LocalDate;
import java.time.LocalTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;

@Slf4j
@Service
@EnableScheduling
@RequiredArgsConstructor
public class WeatherService {

  private List<WeatherHour> hours = new ArrayList<>();

  private final WeatherConfig weatherConfig;

  private final ObjectMapper objectMapper;

  @NonNull
  public List<WeatherHour> all() {
    return new ArrayList<>(hours);
  }

  @Scheduled(cron = "0 0 * * * *")
  @EventListener(ApplicationStartedEvent.class)
  public void update() {
    try {
      final LocalDate today = LocalDate.now();
      final LocalDate first = today.minusDays(weatherConfig.getPastDays());
      final LocalDate end = today.plusDays(weatherConfig.getFutureDays());
      final List<WeatherHour> hours = new ArrayList<>();
      log.debug("Updating Weather...");
      for (LocalDate day = first; !day.isAfter(end); day = day.plusDays(1)) {
        fetchDay(day).getWeather().stream().map(WeatherHour::new).forEach(hours::add);
      }
      this.hours = hours;
      log.info("Weather update complete");
    } catch (Exception e) {
      log.error("Failed fetching Weather data: {}", e.toString());
    }
  }

  @NonNull
  public BrightSkyDto fetchDay(@NonNull final LocalDate day) throws IOException {
    final String url = weatherConfig
      .getUrlPattern()
      .replace("{date}", ZonedDateTime.of(day, LocalTime.MIDNIGHT, ZoneId.systemDefault()).format(DateTimeFormatter.ISO_OFFSET_DATE_TIME))
      .replace("{latitude}", weatherConfig.getLatitude() + "")
      .replace("{longitude}", weatherConfig.getLongitude() + "");
    final HttpURLConnection connection = (HttpURLConnection) URI.create(url).toURL().openConnection();
    final int responseCode = connection.getResponseCode();
    final byte[] bytes = connection.getInputStream().readAllBytes();
    if (responseCode / 100 != 2) {
      throw new IOException("responseCode=%d, message: %s".formatted(responseCode, new String(bytes, StandardCharsets.UTF_8)));
    }
    return objectMapper.readValue(bytes, BrightSkyDto.class);
  }

}