// 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 <glog/logging.h>

#include <set>

#include <string>

#include <utility>

#include <vector>

namespace doris {

class LambdaExecutionContext {

public:

    struct Binding {

        std::string name;

        int column_position = -1;

    };

    struct Frame {

        bool bind_by_name = true;

        bool parent_bindings_visible = true;

        std::vector<Binding> argument_bindings;

    };

    struct ResolveResult {

        bool searched_named_scope = false;

        bool found = false;

        int column_position = -1;

    };

    class FrameGuard {

    public:

        FrameGuard(LambdaExecutionContext& context, Frame frame) : _context(&context) {

            _context->push_frame(std::move(frame));

        }

        FrameGuard(FrameGuard&& other) = delete;

        FrameGuard& operator=(FrameGuard&& other) = delete;

        FrameGuard(const FrameGuard&) = delete;

        FrameGuard& operator=(const FrameGuard&) = delete;

        ~FrameGuard() { release(); }

    private:

        void release() {

            if (_context != nullptr) {

                _context->pop_frame();

                _context = nullptr;

            }

        }

        LambdaExecutionContext* _context;

    };

    void push_frame(Frame frame) { _frames.push_back(std::move(frame)); }

    void pop_frame() {

        DCHECK(!_frames.empty());

        _frames.pop_back();

    }

    ResolveResult resolve_column_position(const std::string& name) const {

        ResolveResult result;

        for (auto frame_it = _frames.rbegin(); frame_it != _frames.rend(); ++frame_it) {

            const auto& frame = *frame_it;

            result.searched_named_scope |= frame.bind_by_name;

            for (auto binding_it = frame.argument_bindings.rbegin();

                 binding_it != frame.argument_bindings.rend(); ++binding_it) {

                const auto& argument_binding = *binding_it;

                if (argument_binding.name == name) {

                    result.found = true;

                    result.column_position = argument_binding.column_position;

                    return result;

                }

            }

            if (!frame.parent_bindings_visible) {

                break;

            }

        }

        return result;

    }

    void collect_visible_binding_column_positions(std::set<int>& column_positions) const {

        for (auto frame_it = _frames.rbegin(); frame_it != _frames.rend(); ++frame_it) {

            for (const auto& binding : frame_it->argument_bindings) {

                if (binding.column_position >= 0) {

                    column_positions.insert(binding.column_position);

                }

            }

            if (!frame_it->parent_bindings_visible) {

                break;

            }

        }

    }

private:

    std::vector<Frame> _frames;

};

} // namespace doris