from datetime import date, datetime
from .test_commons import *
from vertica_python import errors
from vertica_python.vertica.column import timestamp_parse


class DateParsingTestCase(VerticaTestCase):
    """
    Testing DATE type parsing with focus on AD/BC and lack of support for dates Before Christ.

    Note: the 'BC' or 'AD' era indicators in Vertica's date format seem to make Vertica behave as follows:

     - Both 'BC' and 'AD' are simply a flags that tell Vertica: include era indicator if the date is Before
       Christ
     - Dates in AD will never include era indicator
    """
    def _query_to_date(self, expression, pattern):
        return self.query_and_fetchall("SELECT TO_DATE('%(expression)s', '%(pattern)s')" % locals())

    def _assert_date(self, expression, pattern, expected):
        res = self._query_to_date(expression, pattern)

        if len(res) == 0:
            self.fail("Expected that query '%(query)s' would return one row with one column. Got nothing." % locals())

        elif len(res[0]) == 0:
            self.fail("Expected that query '%(query)s' would return one row and one column. Got one row and no column."
                      % locals())

        self.assertEqual(expected, res[0][0], "Expected date '%s' but got: '%s'" % (str(expected), str(res[0][0])))

    def test_after_christ(self):
        self._assert_date('2000-01-01 AD', 'YYYY-MM-DD BC', date(2000, 1, 1))
        self._assert_date('2000-01-01 AD', 'YYYY-MM-DD AD', date(2000, 1, 1))
        self._assert_date('2000-01-01', 'YYYY-MM-DD', date(2000, 1, 1))

    def test_before_christ_bc_indicator(self):
        try:
            res = self._query_to_date('2000-01-01 BC', 'YYYY-MM-DD BC')

            self.fail("Expected to see NotSupportedError when Before Christ date is encountered. Got: " + str(res))
        except errors.NotSupportedError:
            pass

    def test_before_christ_ad_indicator(self):
        try:
            res = self._query_to_date('2000-01-01 BC', 'YYYY-MM-DD AD')

            self.fail("Expected to see NotSupportedError when Before Christ date is encountered. Got: " + str(res))
        except errors.NotSupportedError:
            pass


class TimestampParsingTestCase(VerticaTestCase):
    """Verify timestamp parsing works properly."""

    def test_timestamp_parser(self):
        test_timestamp = '1841-05-05 22:07:58'.encode(encoding='utf-8', errors='strict')
        parsed_timestamp = timestamp_parse(test_timestamp)
        # Assert parser default to strptime
        self.assertEqual(datetime(year=1841, month=5, day=5, hour=22, minute=7, second=58), parsed_timestamp)

    def test_timestamp_with_year_over_9999(self):
        test_timestamp = '44841-05-05 22:07:58'.encode(encoding='utf-8', errors='strict')
        parsed_timestamp = timestamp_parse(test_timestamp)
        # Assert year was truncated properly
        self.assertEqual(datetime(year=9999, month=5, day=5, hour=22, minute=7, second=58), parsed_timestamp)

    def test_timestamp_with_year_over_9999_and_ms(self):
        test_timestamp = '124841-05-05 22:07:58.000003'.encode(encoding='utf-8', errors='strict')
        parsed_timestamp = timestamp_parse(test_timestamp)
        # Assert year was truncated properly
        self.assertEqual(datetime(year=9999, month=5, day=5, hour=22, minute=7, second=58, microsecond=3), parsed_timestamp)