// 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/Functions/IsNotNull.cpp

// and modified by Doris

#include <stddef.h>

#include <algorithm>

#include <boost/iterator/iterator_facade.hpp>

#include <memory>

#include <string>

#include <utility>

#include "common/status.h"

#include "core/assert_cast.h"

#include "core/block/block.h"

#include "core/block/column_numbers.h"

#include "core/block/column_with_type_and_name.h"

#include "core/column/column.h"

#include "core/column/column_nullable.h"

#include "core/column/column_vector.h"

#include "core/data_type/data_type_number.h"

#include "core/field.h"

#include "exprs/aggregate/aggregate_function.h"

#include "exprs/expr_zonemap_filter.h"

#include "exprs/function/function.h"

#include "exprs/vslot_ref.h"

namespace doris {

class FunctionContext;

} // namespace doris

namespace doris {

/// Implements the function isNotNull which returns true if a value

/// is not null, false otherwise.

class FunctionIsNotNull : public IFunction {

public:

    static constexpr auto name = "is_not_null_pred";

    static FunctionPtr create() { return std::make_shared<FunctionIsNotNull>(); }

    std::string get_name() const override { return name; }

    size_t get_number_of_arguments() const override { return 1; }

    bool use_default_implementation_for_nulls() const override { return false; }

    DataTypePtr get_return_type_impl(const DataTypes&) const override {

        return std::make_shared<DataTypeUInt8>();

    }

    ZoneMapFilterResult evaluate_zonemap_filter(const ZoneMapEvalContext& ctx,

                                                const VExprSPtrs& arguments) const override {

        return expr_zonemap::eval_null_zonemap(ctx, arguments, false);

    }

    bool can_evaluate_zonemap_filter(const VExprSPtrs& arguments) const override {

        return std::dynamic_pointer_cast<VSlotRef>(arguments[0]) != nullptr;

    }

    Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,

                        uint32_t result, size_t input_rows_count) const override {

        const ColumnWithTypeAndName& elem = block.get_by_position(arguments[0]);

        if (auto* nullable = check_and_get_column<ColumnNullable>(*elem.column)) {

            /// Return the negated null map.

            auto res_column = ColumnUInt8::create(input_rows_count);

            const auto* __restrict src_data = nullable->get_null_map_data().data();

            auto* __restrict res_data = res_column->get_data().data();

            for (size_t i = 0; i < input_rows_count; ++i) {

                res_data[i] = !src_data[i];

            }

            block.replace_by_position(result, std::move(res_column));

        } else {

            /// Since no element is nullable, return a constant one.

            block.get_by_position(result).column = DataTypeUInt8().create_column_const(

                    elem.column->size(), Field::create_field<TYPE_BOOLEAN>(1));

        }

        return Status::OK();

    }

    Status evaluate_inverted_index(

            const ColumnsWithTypeAndName& arguments,

            const std::vector<IndexFieldNameAndTypePair>& data_type_with_names,

            std::vector<segment_v2::IndexIterator*> iterators, uint32_t num_rows,

            const InvertedIndexAnalyzerCtx* /*analyzer_ctx*/,

            segment_v2::InvertedIndexResultBitmap& bitmap_result) const override {

        if (iterators.empty() || iterators[0] == nullptr) {

            return Status::OK();

        }

        auto* index_iter = iterators[0];

        if (index_iter->has_null()) {

            segment_v2::InvertedIndexQueryCacheHandle null_bitmap_cache_handle;

            RETURN_IF_ERROR(index_iter->read_null_bitmap(&null_bitmap_cache_handle));

            std::shared_ptr<roaring::Roaring> null_bitmap = null_bitmap_cache_handle.get_bitmap();

            // only inverted index has null bitmap, so we can calculate

            if (null_bitmap) {

                std::shared_ptr<roaring::Roaring> data_bitmap =

                        std::make_shared<roaring::Roaring>();

                data_bitmap->addRange(0, num_rows);

                // null_bitmap is null bitmap

                bitmap_result = segment_v2::InvertedIndexResultBitmap(data_bitmap, null_bitmap);

                // need to mask out null bitmap

                bitmap_result.mask_out_null();

            }

        }

        return Status::OK();

    }

};

} // namespace doris