import datetime
from unittest import TestCase

from ..converters import Iso8601Serializer


class Iso8601SerializerTestCase(TestCase):
    def _gen_dates(self, start_date, end_date, step=1):
        date = start_date
        while date <= end_date:
            text = '%04d-%02d-%02d' % (date.year, date.month, date.day)
            yield date, text
            date += datetime.timedelta(step)

    def _gen_times(self, step_hours=1, step_minutes=1, step_seconds=1):
        for hour in range(0, 13, step_hours):
            for minute in range(0, 60, step_minutes):
                for second in range(0, 60, step_seconds):
                    text = '%02d:%02d:%02d' % (hour, minute, second)
                    time = datetime.time(hour, minute, second)
                    yield (time, text)

    def _gen_datetimes(self, start_date, end_date, step_days=47, step_hours=1, step_minutes=13, step_seconds=17):
        for date, date_text in self._gen_dates(start_date, end_date, step_days):
            for time, time_text in self._gen_times(step_hours, step_minutes, step_seconds):
                text = '{}T{}'.format(date_text, time_text)
                obj = datetime.datetime.combine(date, time)
                yield (obj, text)

    def test_serialize(self):
        test_data = []

        # Check date objects
        # Populate test data with all days between 1970 and 2070
        test_data += self._gen_dates(datetime.date(1970, 1, 1), datetime.date(2070, 12, 31))
        # Check time objects
        test_data += self._gen_times()
        # Check datetime objects
        test_data += self._gen_datetimes(datetime.date(1999, 1, 1), datetime.date(2035, 12, 31))

        for obj, text in test_data:
            expected = 'ISO8601:{}'.format(text)
            serialized = Iso8601Serializer.serialize(obj)
            self.assertEqual(serialized, expected)

        # Check invalid input
        invalid_values = (
            None, True, False,
            '2019-03-01',
        )
        for value in invalid_values:
            emsg = ('Expected datetime.datetime, datetime.date or datetime.time,'
                    ' not {}'.format(value.__class__.__name__))
            with self.assertRaisesRegex(ValueError, emsg):
                Iso8601Serializer.serialize(value)
            serialized = Iso8601Serializer.serialize(value, ignore_unsupported_input=True)
            self.assertEqual(serialized, value)

    def test_deserialize(self):
        test_data = []

        # Check '<YYYY>-<MM>-<DD>' format
        test_data += self._gen_dates(datetime.date(1970, 1, 1), datetime.date(2070, 12, 31))
        # Check '<HH>:<MM>:<SS>' format
        test_data += self._gen_times()
        # Check '<YYYY>-<MM>-<DD>T<HH>:<MM>:<SS>' format
        test_data += self._gen_datetimes(datetime.date(1999, 1, 1), datetime.date(2035, 12, 31))

        for obj, text in test_data:
            text = 'ISO8601:{}'.format(text)
            deserialized = Iso8601Serializer.deserialize(text)
            self.assertIsInstance(deserialized, obj.__class__)
            self.assertEqual(deserialized, obj)