// 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 <arrow/status.h>

#include "udf/python/python_client.h"

namespace doris {

class PythonUDFClient;

using PythonUDFClientPtr = std::shared_ptr<PythonUDFClient>;

/**

 * Python UDF Client

 *

 * Implements standard UDF (User-Defined Function) pattern with a single evaluation function:

 * - evaluate_func(*args): Process input arguments and return result

 *

 * UDF Characteristics:

 * - Takes scalar or column inputs

 * - Returns scalar or column outputs

 * - Stateless evaluation (each call is independent)

 * - Simple input-output transformation

 *

 * Example:

 * ```python

 * def evaluate_func(x, y):

 *     # Add two numbers

 *     return x + y

 * ```

 *

 * Communication protocol with Python server:

 * 1. Send input batch (RecordBatch with N rows)

 * 2. Python calls evaluate_func() for each row (or vectorized)

 * 3. Receive output batch (RecordBatch with N rows)

 */

class PythonUDFClient : public PythonClient {

public:

    PythonUDFClient() = default;

    ~PythonUDFClient() override = default;

    static Status create(const PythonUDFMeta& func_meta, ProcessPtr process,

                         PythonUDFClientPtr* client);

    /**

     * Evaluate UDF on input rows

     *

     * @param input Input row batch (columns = UDF function parameters)

     * @param output Output row batch (single column = UDF return value)

     * @return Status

     */

    Status evaluate(const arrow::RecordBatch& input, std::shared_ptr<arrow::RecordBatch>* output);

private:

    DISALLOW_COPY_AND_ASSIGN(PythonUDFClient);

};

} // namespace doris