// 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.

// This file is copied from

// https://github.com/ClickHouse/ClickHouse/blob/master/src/AggregateFunctions/AggregateFunctionAvg.cpp

// and modified by Doris

#include "exprs/aggregate/aggregate_function_avg.h"

#include "core/data_type/define_primitive_type.h"

#include "core/field.h"

#include "exprs/aggregate/aggregate_function_simple_factory.h"

#include "exprs/aggregate/helpers.h"

namespace doris {

constexpr PrimitiveType result_type(PrimitiveType T) {

    if (T == TYPE_LARGEINT || T == TYPE_BIGINT) {

        return TYPE_LARGEINT;

    } else if (is_int_or_bool(T)) {

        return TYPE_BIGINT;

    } else if (is_float_or_double(T) || is_time_type(T)) {

        return TYPE_DOUBLE;

    } else if (is_decimalv3(T) && T != TYPE_DECIMAL256) {

        return TYPE_DECIMAL128I;

    } else {

        return T;

    }

}

// TODO: use result type got from FE plan

template <PrimitiveType T>

struct Avg {

    static constexpr PrimitiveType ResultPType = T == TYPE_DECIMALV2 ? T : TYPE_DOUBLE;

    using Function = AggregateFunctionAvg<T, ResultPType, AggregateFunctionAvgData<result_type(T)>>;

};

template <PrimitiveType T>

using AggregateFuncAvg = typename Avg<T>::Function;

// use result type got from FE plan

template <PrimitiveType InputType, PrimitiveType ResultType>

struct AvgDecimalV3 {

    using Function =

            AggregateFunctionAvg<InputType, ResultType, AggregateFunctionAvgData<ResultType>>;

};

template <PrimitiveType InputType, PrimitiveType ResultType>

using AggregateFuncAvgDecimalV3 = typename AvgDecimalV3<InputType, ResultType>::Function;

void register_aggregate_function_avg(AggregateFunctionSimpleFactory& factory) {

    AggregateFunctionCreator creator = [&](const std::string& name, const DataTypes& types,

                                           const DataTypePtr& result_type,

                                           const bool result_is_nullable,

                                           const AggregateFunctionAttr& attr) {

        if (is_decimalv3(types[0]->get_primitive_type())) {

            return creator_with_type_list<TYPE_DECIMAL32, TYPE_DECIMAL64, TYPE_DECIMAL128I,

                                          TYPE_DECIMAL256>::

                    creator_with_result_type<AggregateFuncAvgDecimalV3>(name, types, result_type,

                                                                        result_is_nullable, attr);

        } else {

            return creator_with_type_list<

                    TYPE_TINYINT, TYPE_SMALLINT, TYPE_INT, TYPE_BIGINT, TYPE_LARGEINT, TYPE_DOUBLE,

                    TYPE_DECIMALV2>::creator<AggregateFuncAvg>(name, types, result_type,

                                                               result_is_nullable, attr);

        }

    };

    factory.register_function_both("avg", creator);

}

} // namespace doris