fix week number calculation

src/main/java/ru/ulstu/utils/timetable/TimetableService.java

@@ -3,6 +3,7 @@ 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;
@@ -50,9 +51,15 @@ public class TimetableService {
     }
 
     private int getCurrentWeek() {
-        Calendar cal = Calendar.getInstance();
-        cal.setTime(new Date());
-        return (cal.get(Calendar.WEEK_OF_YEAR) + 1) % 2;
+        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 {