// 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 <memory>

#include "core/data_type/data_type_number.h"

#include "core/data_type/primitive_type.h"

#include "exprs/aggregate/aggregate_function.h"

#include "util/reservoir_sampler.h"

namespace doris {

class Arena;

class BufferReadable;

struct QuantileReservoirSampler {

    void add(const double x, const double input_level) {

        this->level = input_level;

        data.insert(x);

    }

    void add_batch(const double* values, size_t size, const double input_level) {

        this->level = input_level;

        data.insert_many(values, size);

    }

    void merge(const QuantileReservoirSampler& rhs) {

        level = rhs.level;

        data.merge(rhs.data);

    }

    void reset() {

        level = 0.0;

        data.clear();

    }

    void serialize(BufferWritable& buf) const {

        buf.write_binary(level);

        data.write(buf);

    }

    void deserialize(BufferReadable& buf) {

        buf.read_binary(level);

        data.read(buf);

    }

    double get() const {

        // The caller is a ConstAggregateDataPtr, but it itself is an AggregateDataPtr.

        // To call a non-const method here, a const_cast is required.

        return const_cast<ReservoirSampler&>(data).quantileInterpolated(this->level);

    }

private:

    double level = 0.0;

    ReservoirSampler data;

};

template <typename Data>

class AggregateFunctionPercentileReservoir final

        : public IAggregateFunctionDataHelper<Data, AggregateFunctionPercentileReservoir<Data>>,

          MultiExpression,

          NullableAggregateFunction {

public:

    AggregateFunctionPercentileReservoir(const DataTypes& argument_types_)

            : IAggregateFunctionDataHelper<Data, AggregateFunctionPercentileReservoir<Data>>(

                      argument_types_) {}

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

    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 {

        auto value = assert_cast<const ColumnFloat64&, TypeCheckOnRelease::DISABLE>(*columns[0])

                             .get_data()[row_num];

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

                             .get_data()[0];

        this->data(place).add(value, level);

    }

    void add_batch_single_place(size_t batch_size, AggregateDataPtr place, const IColumn** columns,

                                Arena&) const override {

        const auto& sources =

                assert_cast<const ColumnFloat64&, TypeCheckOnRelease::DISABLE>(*columns[0]);

        const auto& levels =

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

        this->data(place).add_batch(sources.get_data().data(), batch_size, levels.get_data()[0]);

    }

    void add_range_single_place(int64_t partition_start, int64_t partition_end, int64_t frame_start,

                                int64_t frame_end, AggregateDataPtr place, const IColumn** columns,

                                Arena&, UInt8* use_null_result,

                                UInt8* could_use_previous_result) const override {

        frame_start = std::max<int64_t>(frame_start, partition_start);

        frame_end = std::min<int64_t>(frame_end, partition_end);

        if (frame_start < frame_end) {

            const auto& sources =

                    assert_cast<const ColumnFloat64&, TypeCheckOnRelease::DISABLE>(*columns[0]);

            const auto& levels =

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

            this->data(place).add_batch(sources.get_data().data() + frame_start,

                                        frame_end - frame_start, levels.get_data()[0]);

            *use_null_result = false;

            *could_use_previous_result = true;

        } else if (!*could_use_previous_result) {

            *use_null_result = true;

        }

    }

    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).serialize(buf);

    }

    void deserialize(AggregateDataPtr __restrict place, BufferReadable& buf,

                     Arena&) const override {

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

    }

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

        assert_cast<ColumnFloat64&, TypeCheckOnRelease::DISABLE>(to).get_data().push_back(

                this->data(place).get());

    }

};

} // namespace doris