# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
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) -> str:
        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))"
        )