// 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.

#include "common/status.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/data_type/data_type.h"

#include "core/data_type/data_type_nullable.h"

#include "core/types.h"

#include "exprs/function/function.h"

#include "exprs/function/simple_function_factory.h"

namespace doris {

class FunctionContext;

} // namespace doris

namespace doris {

class FunctionNullable : public IFunction {

public:

    static constexpr auto name = "nullable";

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

    String get_name() const override { return name; }

    size_t get_number_of_arguments() const override { return 1; }

    DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {

        return make_nullable(arguments[0]);

    }

    bool use_default_implementation_for_nulls() const override { return false; }

    // trans nullable column to non-nullable column. If argument is already non-nullable, raise error.

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

                        uint32_t result, size_t input_rows_count) const override {

        ColumnPtr& col = block.get_by_position(arguments[0]).column;

        if (const auto* col_null = check_and_get_column<ColumnNullable>(col.get());

            col_null == nullptr) {

            // not null

            block.replace_by_position(

                    result, ColumnNullable::create(col, ColumnBool::create(input_rows_count, 0)));

        } else { // column is ColumnNullable

            block.replace_by_position(result, col->clone_resized(input_rows_count));

        }

        return Status::OK();

    }

};

class FunctionNonNullable : public IFunction {

public:

    static constexpr auto name = "non_nullable";

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

    String get_name() const override { return name; }

    size_t get_number_of_arguments() const override { return 1; }

    DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {

        return remove_nullable(arguments[0]);

    }

    bool use_default_implementation_for_nulls() const override { return false; }

    // trans nullable column to non-nullable column. If argument is already non-nullable, raise error.

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

                        uint32_t result, size_t input_rows_count) const override {

        auto& data = block.get_by_position(arguments[0]);

        if (const auto* col_null = check_and_get_column<ColumnNullable>(data.column.get());

            col_null != nullptr) {

            if (col_null->has_null()) [[unlikely]] {

                return Status::InvalidArgument(

                        "There's NULL value in column {} which is illegal for non_nullable",

                        data.name);

            }

            const ColumnPtr& nest_col = col_null->get_nested_column_ptr();

            block.replace_by_position(result, nest_col->clone_resized(nest_col->size()));

        } else {

            block.replace_by_position(result, data.column->clone_resized(input_rows_count));

        }

        return Status::OK();

    }

};

void register_function_nullables(SimpleFunctionFactory& factory) {

    factory.register_function<FunctionNullable>();

    factory.register_function<FunctionNonNullable>();

}

} // namespace doris