// 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.

#pragma once

#include <gen_cpp/PlanNodes_types.h>

#include <map>

#include <memory>

#include <string>

#include <vector>

#include "common/factory_creator.h"

#include "common/status.h"

#include "format/generic_reader.h"

#include "runtime/descriptors.h"

namespace doris {

class RuntimeProfile;

class RuntimeState;

namespace io {

class FileReader;

} // namespace io

} // namespace doris

namespace doris {

class Block;

// Lightweight reader that surfaces Parquet footer metadata as a table-valued scan.

// It reads only file footers (no data pages) and emits either schema rows or

// row-group/column statistics based on `mode`.

class ParquetMetadataReader : public GenericReader {

    ENABLE_FACTORY_CREATOR(ParquetMetadataReader);

public:

    class ModeHandler;

    ParquetMetadataReader(std::vector<SlotDescriptor*> slots, RuntimeState* state,

                          RuntimeProfile* profile, TMetaScanRange scan_range);

    ~ParquetMetadataReader() override;

    Status init_reader();

    Status _do_get_next_block(Block* block, size_t* read_rows, bool* eof) override;

    Status close() override;

protected:

    Status _do_init_reader(ReaderInitContext* /*ctx*/) override { return init_reader(); }

private:

    Status _init_from_scan_range(const TMetaScanRange& scan_range);

    Status _build_rows(std::vector<MutableColumnPtr>& columns);

    Status _append_file_rows(const std::string& path, std::vector<MutableColumnPtr>& columns);

    enum class Mode { SCHEMA, METADATA, FILE_METADATA, KEY_VALUE_METADATA, BLOOM_PROBE };

    RuntimeState* _state = nullptr;

    std::vector<SlotDescriptor*> _slots;

    TMetaScanRange _scan_range;

    std::vector<std::string> _paths;

    // File system type and properties for remote Parquet access.

    TFileType::type _file_type = TFileType::FILE_LOCAL;

    std::map<std::string, std::string> _properties;

    std::string _mode;

    Mode _mode_type = Mode::METADATA;

    std::string _bloom_column;

    std::string _bloom_literal;

    bool _eof = false;

    std::unique_ptr<ModeHandler> _mode_handler;

};

} // namespace doris