package de.ph87.data.weather;

import com.fasterxml.jackson.databind.*;
import lombok.*;
import lombok.extern.slf4j.*;
import org.springframework.boot.context.event.*;
import org.springframework.context.event.EventListener;
import org.springframework.scheduling.annotation.*;
import org.springframework.stereotype.*;

import java.io.*;
import java.net.*;
import java.nio.charset.*;
import java.time.*;
import java.time.format.*;
import java.util.*;

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

  private List<WeatherDay> days = new ArrayList<>();

  private final WeatherConfig weatherConfig;

  private final ObjectMapper objectMapper;

  @NonNull
  public List<WeatherDay> all() {
    return new ArrayList<>(days);
  }

  @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<WeatherDay> newDays = new ArrayList<>();
      log.debug("Updating Weather...");
      for (LocalDate day = first; !day.isAfter(end); day = day.plusDays(1)) {
        final WeatherDay weatherDay = new WeatherDay(fetchDay(day));
        newDays.add(weatherDay);
        if (log.isDebugEnabled()) {
          log.debug("  {}:", weatherDay);
          for (WeatherDay.Hour hour : weatherDay.getHours()) {
            log.debug("    %s: %4s clouds, %9s, %4s".formatted(hour.date.toLocalTime(), hour.getClouds(), hour.getIrradiation(), hour.getPrecipitation()));
          }
        }
      }
      days = newDays;
      log.info("Weather update complete");
    } catch (IOException e) {
      log.error(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);
  }

}