// 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 <cstddef>

#include <cstring>

#include <memory>

#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_string.h"

#include "core/column/column_vector.h"

#include "core/data_type/data_type.h"

#include "core/data_type/data_type_nullable.h"

#include "core/data_type/data_type_number.h"

#include "core/data_type/data_type_string.h"

#include "core/types.h"

#include "exprs/aggregate/aggregate_function.h"

#include "exprs/function/function.h"

#include "exprs/function/simple_function_factory.h"

namespace doris {

class FunctionContext;

} // namespace doris

namespace doris {

constexpr static std::array<int, 5> SPLIT_POS = {8, 13, 18, 23, 36}; // 8-4-4-4-12

constexpr static char DELIMITER = '-';

class FunctionUuidtoInt : public IFunction {

public:

    static constexpr auto name = "uuid_to_int";

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

    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(std::make_shared<DataTypeInt128>());

    }

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

                        uint32_t result, size_t input_rows_count) const override {

        const auto& arg_column =

                assert_cast<const ColumnString&>(*block.get_by_position(arguments[0]).column);

        auto result_column = ColumnInt128::create(input_rows_count);

        auto& result_data = result_column->get_data();

        auto null_column = ColumnUInt8::create(input_rows_count);

        auto& null_map = null_column->get_data();

        for (int row = 0; row < input_rows_count; row++) {

            auto str = arg_column.get_data_at(row);

            const auto* data = str.data;

            Int128* result_cell = &result_data[row];

            *result_cell = 0;

            null_map[row] = false;

            if (str.size == 36) {

                if (data[SPLIT_POS[0]] != DELIMITER || data[SPLIT_POS[1]] != DELIMITER ||

                    data[SPLIT_POS[2]] != DELIMITER || data[SPLIT_POS[3]] != DELIMITER) {

                    null_map[row] = true;

                    continue;

                }

                char new_data[32];

                memset(new_data, 0, sizeof(new_data));

                // ignore '-'

                memcpy(new_data, data, 8);

                memcpy(new_data + 8, data + SPLIT_POS[0] + 1, 4);

                memcpy(new_data + 12, data + SPLIT_POS[1] + 1, 4);

                memcpy(new_data + 16, data + SPLIT_POS[2] + 1, 4);

                memcpy(new_data + 20, data + SPLIT_POS[3] + 1, 12);

                if (!serialize(new_data, (char*)result_cell, 32)) {

                    null_map[row] = true;

                    continue;

                }

            } else if (str.size == 32) {

                if (!serialize(data, (char*)result_cell, 32)) {

                    null_map[row] = true;

                    continue;

                }

            } else {

                null_map[row] = true;

                continue;

            }

        }

        block.replace_by_position(

                result, ColumnNullable::create(std::move(result_column), std::move(null_column)));

        return Status::OK();

    }

    // use char* to write dst is the only legal way by 'restrict aliasing rule'

    static bool serialize(const char* __restrict src, char* __restrict dst, size_t length) {

        char target; // 8bit, contains 2 char input

        auto translate = [&target](const char ch) {

            if (isdigit(ch)) {

                target += ch - '0';

            } else if (ch >= 'a' && ch <= 'f') {

                target += ch - 'a' + 10;

            } else if (ch >= 'A' && ch <= 'F') {

                target += ch - 'A' + 10;

            } else {

                return false;

            }

            return true;

        };

        bool ok = true;

        for (size_t i = 0; i < length; i += 2, src++, dst++) {

            target = 0;

            if (!translate(*src)) {

                ok = false; // dont break for auto-simd

            }

            src++;

            target <<= 4;

            if (!translate(*src)) {

                ok = false;

            }

            *dst = target;

        }

        return ok;

    }

};

class FunctionInttoUuid : public IFunction {

public:

    static constexpr auto name = "int_to_uuid";

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

    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 auto& arg_column =

                assert_cast<const ColumnInt128&>(*block.get_by_position(arguments[0]).column);

        auto result_column = ColumnString::create();

        constexpr int str_length = 36;

        auto& col_data = result_column->get_chars();

        auto& col_offset = result_column->get_offsets();

        col_data.resize(str_length * input_rows_count +

                        1); // for branchless deserialize, we occupy one more byte for the last '-'

        col_offset.resize(input_rows_count);

        for (int row = 0; row < input_rows_count; row++) {

            const Int128* arg = &arg_column.get_data()[row];

            col_offset[row] = col_offset[row - 1] + str_length;

            deserialize((char*)arg, col_data.data() + str_length * row);

        }

        col_data.resize(str_length * input_rows_count);

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

        return Status::OK();

    }

    // use char* to read src is the only legal way by 'restrict aliasing rule'

    static void deserialize(const char* __restrict src, unsigned char* __restrict dst) {

        auto transform = [](char ch) -> unsigned char {

            if (ch < 10) {

                return ch + '0';

            } else {

                return ch - 10 + 'a';

            }

        };

        int j = 0;

        for (int i : SPLIT_POS) {

            for (; j < i; src++, j += 2) { // input 16 chars, 2 data per char

                dst[j] = transform(((*src) >> 4) & 0x0F);

                dst[j + 1] = transform(*src & 0x0F);

            }

            dst[j++] = DELIMITER; // we resized one more byte.

        }

    }

};

void register_function_uuid_transforms(SimpleFunctionFactory& factory) {

    factory.register_function<FunctionUuidtoInt>();

    factory.register_function<FunctionInttoUuid>();

}

} // namespace doris