// 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.

#include "format_v2/table/hive_reader.h"

#include <utility>

#include "format_v2/column_mapper.h"

#include "format_v2/file_reader.h"

#include "runtime/runtime_state.h"

namespace doris::hive {

Status HiveReader::init(format::TableReadOptions&& options) {

    const bool allow_missing_columns = options.allow_missing_columns;

    const format::FileFormat file_format = options.format;

    RETURN_IF_ERROR(format::TableReader::init(std::move(options)));

    // Hive-specific behavior: choose the column matching mode based on file format and the

    // matching session variable.

    //   - hive_orc_use_column_names / hive_parquet_use_column_names == true

    //     => BY_NAME (modern Hive default, match by column name)

    //   - those options == false

    //     => BY_INDEX (mainly for Hive1 ORC `_col0` / `_col1`, match by top-level position;

    //                  Parquet exposes the same switch for consistency)

    // The base init path does not accept file-format-specific mapper configuration, so the mapper

    // must be replaced here after the base initialization completes.

    DORIS_CHECK(_runtime_state != nullptr);

    const auto& query_options = _runtime_state->query_options();

    bool use_column_names = true;

    switch (file_format) {

    case format::FileFormat::ORC:

        use_column_names = query_options.hive_orc_use_column_names;

        break;

    case format::FileFormat::PARQUET:

        use_column_names = query_options.hive_parquet_use_column_names;

        break;

    case format::FileFormat::CSV:

        // CSV does not really have a "column name vs position" choice. The format is inherently

        // positional, so BY_INDEX is the closest match to the original behavior.

        use_column_names = false;

        break;

    }

    _mode = use_column_names ? format::TableColumnMappingMode::BY_NAME

                             : format::TableColumnMappingMode::BY_INDEX;

    _mapper_options.allow_missing_columns = allow_missing_columns;

    return Status::OK();

}

} // namespace doris::hive