package ru.ulstu.utils.timetable;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;
import ru.ulstu.core.util.DateUtils;
import ru.ulstu.utils.timetable.errors.TimetableClientException;
import ru.ulstu.utils.timetable.model.Lesson;
import ru.ulstu.utils.timetable.model.TimetableResponse;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

public class TimetableService {
    private static final String TIMETABLE_URL = "http://timetable.athene.tech/api/1.0/timetable?filter=%s";
    private final SimpleDateFormat lessonTimeFormat = new SimpleDateFormat("hh:mm");

    private final long[] lessonsStarts = new long[]{
            lessonTimeFormat.parse("8:00:00").getTime(),
            lessonTimeFormat.parse("9:40:00").getTime(),
            lessonTimeFormat.parse("11:30:00").getTime(),
            lessonTimeFormat.parse("13:10:00").getTime(),
            lessonTimeFormat.parse("14:50:00").getTime(),
            lessonTimeFormat.parse("16:30:00").getTime(),
            lessonTimeFormat.parse("18:10:00").getTime(),
    };

    public TimetableService() throws ParseException {
    }

    private int getCurrentDay() {
        Calendar calendar = Calendar.getInstance();
        int day = calendar.get(Calendar.DAY_OF_WEEK);
        return (day + 5) % 7;
    }

    private int getCurrentLessonNumber() {
        long lessonDuration = 90 * 60000;
        Date now = new Date();
        long timeNow = now.getTime() % (24 * 60 * 60 * 1000L);

        for (int i = 0; i < lessonsStarts.length; i++) {
            if (timeNow > lessonsStarts[i] && timeNow < lessonsStarts[i] + lessonDuration) {
                return i;
            }
        }
        return -1;
    }

    private int getCurrentWeek() {
        Date currentDate = Calendar.getInstance().getTime();
        currentDate = DateUtils.clearTime(currentDate);

        Calendar firstJan = Calendar.getInstance();
        firstJan.set(Calendar.MONTH, 0);
        firstJan.set(Calendar.DAY_OF_MONTH, 1);

        return (int) Math.round(Math.ceil((((currentDate.getTime() - firstJan.getTime().getTime()) / 86400000)
                + DateUtils.addDays(firstJan.getTime(), 1).getTime() / 7) % 2));
    }

    private TimetableResponse getTimetableForUser(String userFIO) throws RestClientException {
        RestTemplate restTemplate = new RestTemplate();
        return restTemplate.getForObject(String.format(TIMETABLE_URL, userFIO), TimetableResponse.class);
    }

    public Lesson getCurrentLesson(String userFio) {
        TimetableResponse response;
        try {
            response = getTimetableForUser(userFio);
        } catch (RestClientException e) {
            e.printStackTrace();
            throw new TimetableClientException(userFio);
        }

        int lessonNumber = getCurrentLessonNumber();
        if (lessonNumber < 0) {
            return null;
        }

        List<Lesson> lessons = response
                .getResponse()
                .getWeeks()
                .get(getCurrentWeek())
                .getDays()
                .get(getCurrentDay())
                .getLessons()
                .get(lessonNumber);

        if (lessons.size() == 0) {
            return null;
        }
        return new ObjectMapper().convertValue(lessons.get(0), Lesson.class);
    }
}