utils.py

# Copyright (c) 2025, Salesforce, Inc.
# SPDX-License-Identifier: Apache-2
#
# Licensed 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 __future__ import annotations

from typing import TYPE_CHECKING

import pandas.api.types as pd_types
from pyspark.sql.types import (
    BooleanType,
    DoubleType,
    LongType,
    StringType,
    StructField,
    StructType,
    TimestampType,
)

if TYPE_CHECKING:
    import pandas
    from pyspark.sql.types import AtomicType

PANDAS_TYPE_MAPPING = {
    "object": StringType(),
    "int64": LongType(),
    "float64": DoubleType(),
    "bool": BooleanType(),
}


def _pandas_to_spark_schema(
    pandas_df: pandas.DataFrame, nullable: bool = True
) -> StructType:
    fields = []
    for column, dtype in pandas_df.dtypes.items():
        spark_type: AtomicType
        if pd_types.is_datetime64_any_dtype(dtype):
            spark_type = TimestampType()
        else:
            spark_type = PANDAS_TYPE_MAPPING.get(str(dtype), StringType())
        fields.append(StructField(column.lower(), spark_type, nullable))
    return StructType(fields)