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# pylint: disable=C,R,W
from superset.db_engine_specs.base import BaseEngineSpec, LimitMethod


class TeradataEngineSpec(BaseEngineSpec):
    """Dialect for Teradata DB."""
    engine = 'teradata'
    limit_method = LimitMethod.WRAP_SQL
    max_column_name_length = 30  # since 14.10 this is 128

    time_grain_functions = {
        None: '{col}',
        'PT1M': "TRUNC(CAST({col} as DATE), 'MI')",
        'PT1H': "TRUNC(CAST({col} as DATE), 'HH')",
        'P1D': "TRUNC(CAST({col} as DATE), 'DDD')",
        'P1W': "TRUNC(CAST({col} as DATE), 'WW')",
        'P1M': "TRUNC(CAST({col} as DATE), 'MONTH')",
        'P0.25Y': "TRUNC(CAST({col} as DATE), 'Q')",
        'P1Y': "TRUNC(CAST({col} as DATE), 'YEAR')",
    }

    @classmethod
    def epoch_to_dttm(cls):
        return "CAST(((CAST(DATE '1970-01-01' + ({col} / 86400) AS TIMESTAMP(0) " \
               "AT 0)) AT 0) + (({col} MOD 86400) * INTERVAL '00:00:01' " \
               'HOUR TO SECOND) AS TIMESTAMP(0))'