// 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 <stddef.h>

#include <algorithm>

#include <boost/iterator/iterator_facade.hpp>

#include <cmath>

#include <memory>

#include <type_traits>

#include "common/status.h"

#include "core/assert_cast.h"

#include "core/binary_cast.hpp"

#include "core/column/column_vector.h"

#include "core/data_type/data_type_number.h"

#include "core/types.h"

#include "core/value/decimalv2_value.h"

#include "exprs/aggregate/aggregate_function.h"

#include "util/io_helper.h"

namespace doris {

class Arena;

class BufferReadable;

class BufferWritable;

class IColumn;

template <PrimitiveType T>

class ColumnDecimal;

template <PrimitiveType T>

struct AggregateFunctionAvgWeightedData {

    using DataType = typename PrimitiveTypeTraits<T>::CppType;

    void add(const DataType& data_val, double weight_val) {

#ifdef __clang__

#pragma clang fp reassociate(on)

#endif

        data_sum = data_sum + (double(data_val) * weight_val);

        weight_sum = weight_sum + weight_val;

    }

    void write(BufferWritable& buf) const {

        buf.write_binary(data_sum);

        buf.write_binary(weight_sum);

    }

    void read(BufferReadable& buf) {

        buf.read_binary(data_sum);

        buf.read_binary(weight_sum);

    }

    void merge(const AggregateFunctionAvgWeightedData& rhs) {

#ifdef __clang__

#pragma clang fp reassociate(on)

#endif

        data_sum = data_sum + rhs.data_sum;

        weight_sum = weight_sum + rhs.weight_sum;

    }

    void reset() {

        data_sum = 0.0;

        weight_sum = 0.0;

    }

    double get() const { return data_sum / weight_sum; }

    double data_sum = 0.0;

    double weight_sum = 0.0;

};

template <PrimitiveType type>

class AggregateFunctionAvgWeight final

        : public IAggregateFunctionDataHelper<AggregateFunctionAvgWeightedData<type>,

                                              AggregateFunctionAvgWeight<type>>,

          MultiExpression,

          NullableAggregateFunction {

public:

    using T = typename PrimitiveTypeTraits<type>::CppType;

    using ColVecType = typename PrimitiveTypeTraits<type>::ColumnType;

    AggregateFunctionAvgWeight(const DataTypes& argument_types_)

            : IAggregateFunctionDataHelper<AggregateFunctionAvgWeightedData<type>,

                                           AggregateFunctionAvgWeight<type>>(argument_types_) {}

    String get_name() const override { return "avg_weighted"; }

    DataTypePtr get_return_type() const override { return std::make_shared<DataTypeFloat64>(); }

    void add(AggregateDataPtr __restrict place, const IColumn** columns, ssize_t row_num,

             Arena&) const override {

        const auto& column =

                assert_cast<const ColVecType&, TypeCheckOnRelease::DISABLE>(*columns[0]);

        const auto& weight =

                assert_cast<const ColumnFloat64&, TypeCheckOnRelease::DISABLE>(*columns[1]);

        this->data(place).add(column.get_data()[row_num], weight.get_element(row_num));

    }

    void reset(AggregateDataPtr place) const override { this->data(place).reset(); }

    void merge(AggregateDataPtr __restrict place, ConstAggregateDataPtr rhs,

               Arena&) const override {

        this->data(place).merge(this->data(rhs));

    }

    void serialize(ConstAggregateDataPtr __restrict place, BufferWritable& buf) const override {

        this->data(place).write(buf);

    }

    void deserialize(AggregateDataPtr __restrict place, BufferReadable& buf,

                     Arena&) const override {

        this->data(place).read(buf);

    }

    void insert_result_into(ConstAggregateDataPtr __restrict place, IColumn& to) const override {

        auto& column = assert_cast<ColumnFloat64&>(to);

        column.get_data().push_back(this->data(place).get());

    }

};

} // namespace doris