// 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 <fmt/core.h>

#include <cstddef>

#include <cstdint>

#include "common/status.h"

#include "core/block/block.h"

#include "exprs/vexpr_context.h"

namespace doris {

constexpr auto COMBINATOR_SUFFIX_OUTER = "_outer";

class TableFunction {

public:

    virtual ~TableFunction() = default;

    struct BlockFastPathContext {

        const UInt8* array_nullmap_data = nullptr;

        const IColumn::Offsets64* offsets_ptr = nullptr;

        ColumnPtr nested_col = nullptr;

        const UInt8* nested_nullmap_data = nullptr;

        bool generate_row_index = false;

    };

    virtual Status prepare() { return Status::OK(); }

    virtual Status open() { return Status::OK(); }

    virtual Status process_init(Block* block, RuntimeState* state) = 0;

    virtual void process_row(size_t row_idx) {

        if (!_is_const) {

            _cur_size = 0;

        }

        reset();

    }

    // only used for vectorized.

    virtual void process_close() = 0;

    virtual void reset() {

        _eos = false;

        _cur_offset = 0;

    }

    virtual void get_same_many_values(MutableColumnPtr& column, int length = 0) = 0;

    virtual int get_value(MutableColumnPtr& column, int max_step) = 0;

    virtual bool support_block_fast_path() const { return false; }

    virtual Status prepare_block_fast_path(Block* /*block*/, RuntimeState* /*state*/,

                                           BlockFastPathContext* /*ctx*/) {

        return Status::NotSupported("table function {} doesn't support block fast path", _fn_name);

    }

    virtual Status close() { return Status::OK(); }

    virtual void forward(int step = 1) {

        if (current_empty()) {

            _eos = true;

        } else {

            _cur_offset += step;

            if (_cur_offset >= _cur_size) {

                _eos = true;

            }

        }

    }

    std::string name() const { return _fn_name; }

    bool eos() const { return _eos; }

    void set_expr_context(const VExprContextSPtr& expr_context) { _expr_context = expr_context; }

    void set_nullable() { _is_nullable = true; }

    bool is_outer() const { return _is_outer; }

    void set_outer() {

        if (is_outer()) {

            return;

        }

        _is_outer = true;

        _fn_name += COMBINATOR_SUFFIX_OUTER;

    }

    bool current_empty() const { return _cur_size == 0; }

protected:

    std::string _fn_name;

    VExprContextSPtr _expr_context = nullptr;

    // true if there is no more data can be read from this function.

    bool _eos = false;

    // the position of current cursor

    int64_t _cur_offset = 0;

    // the size of current result

    int64_t _cur_size = 0;

    // set _is_outer to false for explode function, and should not return tuple while array is null or empty

    bool _is_outer = false;

    bool _is_nullable = false;

    bool _is_const = false;

};

} // namespace doris