// Licensed to the LF AI & Data foundation 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 "Operator.h"
#include "plan/PlanNode.h"

namespace milvus {
namespace exec {
class QueryContext;

class PhyProjectNode : public Operator {
 public:
    PhyProjectNode(int32_t operator_id,
                   DriverContext* ctx,
                   const std::shared_ptr<const plan::ProjectNode>& projectNode);

    bool
    IsFilter() const override {
        return false;
    }

    bool
    NeedInput() const override {
        return true;
    }

    void
    AddInput(RowVectorPtr& input) override;

    RowVectorPtr
    GetOutput() override;

    // ProjectNode is a stateless pass-through operator: it transforms input
    // rows on the fly and holds no accumulated state across batches.
    // It is finished when either:
    //   - is_finished_: it has processed its single input batch and produced
    //     output (normal completion after GetOutput succeeds).
    //   - no_more_input_: the upstream operator has no data at all (e.g.,
    //     empty segment with active_count=0). In this case GetOutput is never
    //     called with valid input, so is_finished_ is never set. But since
    //     no future input can arrive, the operator is logically done.
    bool
    IsFinished() override {
        return is_finished_ || no_more_input_;
    }

    BlockingReason
    IsBlocked(ContinueFuture* /* unused */) override {
        return BlockingReason::kNotBlocked;
    }

    std::string
    ToString() const override {
        return "Project Operator";
    }

 private:
    const segcore::SegmentInternalInterface* segment_;
    bool is_finished_{false};
    const std::vector<FieldId> fields_to_project_;
    QueryContext* query_context_;
    OpContext* op_context_;
};
}  // namespace exec
}  // namespace milvus
