// 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 <cstddef>

#include <memory>

#include <string>

#include <unordered_map>

#include <unordered_set>

#include "common/status.h"

#include "format/table/table_format_reader.h"

#include "io/fs/file_reader_writer_fwd.h"

namespace doris {

class RuntimeProfile;

class RuntimeState;

namespace io {

struct IOContext;

} // namespace io

} // namespace doris

namespace doris {

class Block;

// Doris Native format reader.

// it will read a sequence of Blocks encoded in Doris Native binary format.

//

// NOTE: current implementation is just a skeleton and will be filled step by step.

class NativeReader : public TableFormatReader {

public:

    ENABLE_FACTORY_CREATOR(NativeReader);

    NativeReader(RuntimeProfile* profile, const TFileScanRangeParams& params,

                 const TFileRangeDesc& range, io::IOContext* io_ctx, RuntimeState* state);

    NativeReader(RuntimeProfile* profile, const TFileScanRangeParams& params,

                 const TFileRangeDesc& range, std::shared_ptr<io::IOContext> io_ctx_holder,

                 RuntimeState* state);

    ~NativeReader() override;

    // Initialize underlying file reader and any format specific state.

    Status init_reader();

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

    Status _get_columns_impl(std::unordered_map<std::string, DataTypePtr>* name_to_type) override;

    Status init_schema_reader() override;

    Status get_parsed_schema(std::vector<std::string>* col_names,

                             std::vector<DataTypePtr>* col_types) override;

    Status close() override;

    bool count_read_rows() override { return true; }

protected:

    void _collect_profile_before_close() override {}

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

private:

    RuntimeProfile* _profile = nullptr;

    const TFileScanRangeParams& _scan_params;

    const TFileRangeDesc& _scan_range;

    io::FileReaderSPtr _file_reader;

    io::IOContext* _io_ctx = nullptr;

    std::shared_ptr<io::IOContext> _io_ctx_holder;

    RuntimeState* _state = nullptr;

    bool _eof = false;

    // Current read offset in the underlying file.

    int64_t _current_offset = 0;

    int64_t _file_size = 0;

    // Cached schema information from the first PBlock.

    bool _schema_inited = false;

    std::vector<std::string> _schema_col_names;

    std::vector<DataTypePtr> _schema_col_types;

    // Cached first block (serialized) to allow schema probing before data scan.

    std::string _first_block_buf;

    bool _first_block_loaded = false;

    bool _first_block_consumed = false;

    Status _read_next_pblock(std::string* buff, bool* eof);

    Status _init_schema_from_pblock(const PBlock& pblock);

};

} // namespace doris