// 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 <cctype>

#include "common/status.h"

#include "core/column/column_string.h"

#include "core/data_type/data_type_string.h"

#include "exprs/function/function.h"

#include "exprs/function/simple_function_factory.h"

namespace doris {

class FunctionSoundex : public IFunction {

public:

    static constexpr auto name = "soundex";

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

    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 std::make_shared<DataTypeString>();

    }

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

                        uint32_t result, size_t input_rows_count) const override {

        const ColumnPtr col_ptr = block.get_by_position(arguments[0]).column;

        auto res_column = ColumnString::create();

        res_column->reserve(input_rows_count);

        auto& res_data = res_column->get_chars();

        auto& res_offsets = res_column->get_offsets();

        res_data.reserve(input_rows_count * CODE_SIZE);

        res_offsets.resize(input_rows_count);

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

            StringRef ref = col_ptr->get_data_at(i);

            RETURN_IF_ERROR(calculate_soundex_and_insert(ref, res_data, res_offsets, i));

        }

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

        return Status::OK();

    }

private:

    Status calculate_soundex_and_insert(const StringRef& ref, ColumnString::Chars& chars,

                                        ColumnString::Offsets& offsets, const size_t row) const {

        uint32_t row_start = (row == 0) ? 0 : offsets[row - 1];

        uint32_t expect_end = row_start + CODE_SIZE;

        if (ref.size == 0) {

            offsets[row] = row_start;

            return Status::OK();

        }

        char pre_code = '\0';

        for (size_t i = 0; i < ref.size; ++i) {

            auto c = static_cast<unsigned char>(ref.data[i]);

            if (c > 0x7f) {

                return Status::InvalidArgument("soundex only supports ASCII, but got: {}",

                                               ref.data[i]);

            }

            if (!std::isalpha(c)) {

                continue;

            }

            c = static_cast<char>(std::toupper(c));

            if (chars.size() == row_start) {

                chars.push_back(c);

                pre_code = (SOUNDEX_TABLE[c - 'A'] == 'N') ? '\0' : SOUNDEX_TABLE[c - 'A'];

            } else if (char code = SOUNDEX_TABLE[c - 'A']; code != 'N') {

                if (code != 'V' && code != pre_code) {

                    chars.push_back(code);

                    if (chars.size() == expect_end) {

                        offsets[row] = static_cast<ColumnString::Offset>(chars.size());

                        return Status::OK();

                    }

                }

                pre_code = code;

            }

        }

        while (chars.size() != row_start && chars.size() < expect_end) {

            chars.push_back('0');

        }

        offsets[row] = static_cast<ColumnString::Offset>(chars.size());

        return Status::OK();

    }

    /** 1. If a vowel (A, E, I, O, U) separates two consonants that have the same soundex code

     *  the consonant to the right of the vowel is coded. Here we use 'V' to represent vowels.

     *  eg : **Tymczak** is coded as T-522 (T, 5 for the M, 2 for the C, Z ignored , 2 for the K). 

     *  Since the vowel "A" separates the Z and K, the K is coded.

     *

     *  2. If "H" or "W" separate two consonants that have the same soundex code, the consonant to the right of the vowel is NOT coded.

     *  Here we use 'N' to represent these two characters.

     *  eg : **Ashcraft** is coded A-261 (A, 2 for the S, C ignored, 6 for the R, 1 for the F). It is not coded A-226.

     */

    static constexpr char SOUNDEX_TABLE[26] = {'V', '1', '2', '3', 'V', '1', '2', 'N', 'V',

                                               '2', '2', '4', '5', '5', 'V', '1', '2', '6',

                                               '2', '3', 'V', '1', 'N', '2', 'V', '2'};

    static constexpr uint8_t CODE_SIZE = 4;

};

void register_function_soundex(SimpleFunctionFactory& factory) {

    factory.register_function<FunctionSoundex>();

}

} // namespace doris