package org.vaadin.stefan.fullcalendar;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Arrays;
import java.util.List;

public class TimezoneTests {

    public static final ZoneId UTC_ID = ZoneId.of("UTC");
    public static final Timezone CUSTOM_TIMEZONE = new Timezone(ZoneId.of("Europe/Berlin"));

    @Test
    void testStatics() {
        Assertions.assertEquals(UTC_ID, Timezone.UTC.getZoneId());

        List<Timezone> timezoneList = Arrays.asList(Timezone.getAvailableZones());
        Assertions.assertTrue(timezoneList.contains(Timezone.UTC));
    }

    @Test
    void testConstructors() {
        ZoneId zoneId = ZoneId.of("Europe/Berlin");
        Timezone timezone = new Timezone(zoneId);
        Assertions.assertEquals(zoneId, timezone.getZoneId());
        Assertions.assertEquals(zoneId.getId(), timezone.getClientSideValue());

        timezone = new Timezone(zoneId, "someOther");
        Assertions.assertEquals(zoneId, timezone.getZoneId());
        Assertions.assertEquals("someOther", timezone.getClientSideValue());
    }

//    @Test
//    void testFormatting() {
//        Instant now = Instant.now();
//        String utcString = now.toString();
//        String ldtString = DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(LocalDateTime.ofInstant(now, CUSTOM_TIMEZONE.getZoneId()));
//
//        Assertions.assertEquals(utcString, Timezone.UTC.formatWithZoneId(now));
//        Assertions.assertEquals(utcString, new Timezone(UTC_ID).formatWithZoneId(now));
//
//        Assertions.assertEquals(ldtString, CUSTOM_TIMEZONE.formatWithZoneId(now));
//    }

//    @Test
//    void testConversion() {
//        Instant instant = Instant.now();
//
//        // TODO additional tests needed?
//        Assertions.assertEquals(instant, Timezone.UTC.convertToUTC(Timezone.UTC.convertToLocalDateTime(instant)));
//        Assertions.assertEquals(instant, CUSTOM_TIMEZONE.convertToUTC(CUSTOM_TIMEZONE.convertToLocalDateTime(instant)));
//    }

    @Test
    void testSystemTimezone() {
        Timezone system = Timezone.getSystem();
        Assertions.assertEquals(ZoneId.systemDefault(), system.getZoneId());
    }

    @Test
    void test_applyRemoveOffsets() {
        LocalDateTime now = LocalDateTime.now();
        Timezone timezone = new Timezone(ZoneId.of("Etc/GMT-1")); // timezone one hour ahead of UTC, ignoring daylight saving rules, e.g. Germany in winter.
        LocalDateTime nowZoned = now.plusHours(1);

        Assertions.assertEquals(nowZoned, timezone.applyTimezoneOffset(now));
        Assertions.assertEquals(now, timezone.removeTimezoneOffset(nowZoned));

        Assertions.assertEquals(nowZoned, timezone.applyTimezone(now).toLocalDateTime());
        Assertions.assertEquals(now, timezone.removeTimezone(nowZoned).toLocalDateTime());
    }


}