package eirb.pg203;

import org.json.JSONObject;
import org.json.JSONArray;

import eirb.pg203.utils.JSONFetcher;

import java.io.IOException;
import java.net.URI;
import java.net.URL;
import java.time.Clock;
import java.time.DayOfWeek;
import java.time.Instant;
import java.time.ZoneId;
import java.util.ArrayList;
import java.util.Locale;

import eirb.pg203.WeatherData.Condition;

/**
 * OpenWeatherMap api implementation
 */
public class OpenWeatherMap implements WeatherDataAPI {
	private static final String forecastBaseURL = "https://api.openweathermap.org/data/2.5/forecast";
	private String APIKey;
	Clock clock = Clock.systemUTC();
	JSONFetcher JSONFetcher = new JSONFetcher();

	OpenWeatherMap(String APIKey) {
		this.APIKey = APIKey;
	}

  private JSONObject fetchWeather(City city) throws IOException {
    URL url = URI.create(
        String.format(Locale.ENGLISH, forecastBaseURL + "?appid=%s&lat=%.2f&lon=%.2f&units=metric",
					APIKey,
					city.getCityCoords().getLat(),
					city.getCityCoords().getLon()
        )
    ).toURL();

    return JSONFetcher.fetch(url);
  }

	private WeatherData getWeatherDataFromForecast(JSONObject response, int day, String city) {
		JSONArray list = response.getJSONArray("list");

		DayOfWeek targetedDay = Instant.now(clock).plusSeconds(day * 24 * 3600).atZone(ZoneId.systemDefault()).getDayOfWeek();
		DayOfWeek dayOfWeek;
		int dataCount = 0;
		float temp_c = 0;
		float windSpeed = 0;
		float windDirection = 0;
		float pop = 0;  // probability of precipitation
		float cloudiness = 0;  // percent

		for (int i = 0 ; i < list.length() ; ++i)
		{
			JSONObject data = list.getJSONObject(i);
			int timestamp = data.getInt("dt");
			dayOfWeek = Instant.ofEpochSecond(timestamp).atZone(ZoneId.systemDefault()).getDayOfWeek();

			if (dayOfWeek == targetedDay)
			{
				temp_c += data.getJSONObject("main").getFloat("temp");
				windSpeed += data.getJSONObject("wind").getFloat("speed");
				windDirection += data.getJSONObject("wind").getFloat("deg");
				cloudiness += data.getJSONObject("clouds").getFloat("all");
				pop += data.getFloat("pop");
				dataCount++;
			}
		}

		if (dataCount != 0)
		{
			temp_c /= dataCount;
			windSpeed /= dataCount;
			windDirection /= dataCount;
			pop /= dataCount;
			cloudiness /= dataCount;
		}

		Condition condition = Condition.SUNNY;
		if (pop > 50)
			condition = Condition.RAINY;
		else if (cloudiness > 75)
			condition = Condition.CLOUDY;
		else if (cloudiness > 25)
			condition = Condition.PARTIAL;


        return new WeatherData(
				new City(city),
				Instant.now(clock).plusSeconds(day * 24 * 3600),
				temp_c,
				windSpeed,
				windDirection,
				condition
			);
	}

  /**
   * @param day Day, 0 &leq; day &leq; 14
   */
  @Override
  public WeatherData getTemperature(int day, String city) throws IOException {
    JSONObject result = fetchWeather(new City(city));

    return getWeatherDataFromForecast(result, day, city);
  }

  @Override
  public WeatherData getTemperature(int day, int hour, String city) throws IOException{
    return getTemperature(day, city);
  }

  @Override
  public ArrayList<WeatherData> getTemperatures(int days, String city) throws IOException {
    JSONObject result = fetchWeather(new City(city));

    ArrayList<WeatherData> weatherDatas = new ArrayList<>();

    for (int day = 0; day < days ; ++day) {
		weatherDatas.add(
			getWeatherDataFromForecast(result, day, city)
		);
    }

    return weatherDatas;
  }

  @Override
  public String getAPIName() {
    return "OpenWeatherMap";
  }

  @Override
  public String toString() {
	  return this.getAPIName();
  }
}