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# 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
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# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
from datetime import datetime
from typing import Optional

from superset.db_engine_specs.base import LimitMethod
from superset.db_engine_specs.postgres import PostgresBaseEngineSpec
from superset.utils import core as utils


class HanaEngineSpec(PostgresBaseEngineSpec):
    engine = "hana"
    engine_name = "SAP HANA"
    limit_method = LimitMethod.WRAP_SQL
    force_column_alias_quotes = True
    max_column_name_length = 30

    _time_grain_expressions = {
        None: "{col}",
        "PT1S": "TO_TIMESTAMP(SUBSTRING(TO_TIMESTAMP({col}),0,20))",
        "PT1M": "TO_TIMESTAMP(SUBSTRING(TO_TIMESTAMP({col}),0,17) || '00')",
        "PT1H": "TO_TIMESTAMP(SUBSTRING(TO_TIMESTAMP({col}),0,14) || '00:00')",
        "P1D": "TO_DATE({col})",
        "P1M": "TO_DATE(SUBSTRING(TO_DATE({col}),0,7)||'-01')",
        "P0.25Y": "TO_DATE(SUBSTRING( \
                   TO_DATE({col}), 0, 5)|| LPAD(CAST((CAST(SUBSTRING(QUARTER( \
                   TO_DATE({col}), 1), 7, 1) as int)-1)*3 +1 as text),2,'0') ||'-01')",
        "P1Y": "TO_DATE(YEAR({col})||'-01-01')",
    }

    @classmethod
    def convert_dttm(cls, target_type: str, dttm: datetime) -> Optional[str]:
        tt = target_type.upper()
        if tt == utils.TemporalType.DATE:
            return f"TO_DATE('{dttm.date().isoformat()}', 'YYYY-MM-DD')"
        if tt == utils.TemporalType.TIMESTAMP:
            return f"""TO_TIMESTAMP('{dttm
                .isoformat(timespec="microseconds")}', 'YYYY-MM-DD"T"HH24:MI:SS.ff6')"""
        return None