// 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 <glog/logging.h>

#include <array>

#include <cctype>

#include <cstddef>

#include <cstring>

#include <functional>

#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_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"

#include "util/block_compression.h"

#include "util/faststring.h"

namespace doris {

class FunctionContext;

} // namespace doris

namespace doris {

static constexpr int COMPRESS_STR_LENGTH = 4;

class FunctionCompress : public IFunction {

public:

    static constexpr auto name = "compress";

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

    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 {

        // Get the compression algorithm object

        BlockCompressionCodec* compression_codec;

        RETURN_IF_ERROR(get_block_compression_codec(segment_v2::CompressionTypePB::ZLIB,

                                                    &compression_codec));

        const auto& arg_column =

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

        auto result_column = ColumnString::create();

        auto& arg_data = arg_column.get_chars();

        auto& arg_offset = arg_column.get_offsets();

        const char* arg_begin = reinterpret_cast<const char*>(arg_data.data());

        auto& col_data = result_column->get_chars();

        auto& col_offset = result_column->get_offsets();

        col_offset.resize(input_rows_count);

        faststring compressed_str;

        Slice data;

        // When the original string is large, the result is roughly this value

        size_t total = arg_offset[input_rows_count - 1];

        col_data.reserve(total / 1000);

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

            uint32_t length = arg_offset[row] - arg_offset[row - 1];

            data = Slice(arg_begin + arg_offset[row - 1], length);

            size_t idx = col_data.size();

            if (!length) { // data is ''

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

                continue;

            }

            // Z_MEM_ERROR and Z_BUF_ERROR are already handled in compress, making sure st is always Z_OK

            RETURN_IF_ERROR(compression_codec->compress(data, &compressed_str));

            col_data.resize(col_data.size() + COMPRESS_STR_LENGTH + compressed_str.size());

            std::memcpy(col_data.data() + idx, &length, sizeof(length));

            idx += COMPRESS_STR_LENGTH;

            // The length of compress_str is not known in advance, so it cannot be compressed directly into col_data

            unsigned char* src = compressed_str.data();

            for (size_t i = 0; i < compressed_str.size(); idx++, i++, src++) {

                col_data[idx] = *src;

            }

            col_offset[row] =

                    col_offset[row - 1] + COMPRESS_STR_LENGTH + (int)compressed_str.size();

        }

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

        return Status::OK();

    }

};

class FunctionUncompress : public IFunction {

public:

    static constexpr auto name = "uncompress";

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

    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<DataTypeString>());

    }

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

                        uint32_t result, size_t input_rows_count) const override {

        // Get the compression algorithm object

        BlockCompressionCodec* compression_codec;

        RETURN_IF_ERROR(get_block_compression_codec(segment_v2::CompressionTypePB::ZLIB,

                                                    &compression_codec));

        const auto& arg_column =

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

        auto& arg_data = arg_column.get_chars();

        auto& arg_offset = arg_column.get_offsets();

        const char* arg_begin = reinterpret_cast<const char*>(arg_data.data());

        auto result_column = ColumnString::create();

        auto& col_data = result_column->get_chars();

        auto& col_offset = result_column->get_offsets();

        col_offset.resize(input_rows_count);

        auto null_column = ColumnUInt8::create(input_rows_count);

        auto& null_map = null_column->get_data();

        std::string uncompressed;

        Slice data;

        Slice uncompressed_slice;

        size_t total = arg_offset[input_rows_count - 1];

        col_data.reserve(total * 1000);

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

            null_map[row] = false;

            data = Slice(arg_begin + arg_offset[row - 1], arg_offset[row] - arg_offset[row - 1]);

            size_t data_length = arg_offset[row] - arg_offset[row - 1];

            if (data_length == 0) { // The original data is ''

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

                continue;

            }

            union {

                char bytes[COMPRESS_STR_LENGTH];

                uint32_t value;

            } length;

            std::memcpy(length.bytes, data.data, COMPRESS_STR_LENGTH);

            size_t idx = col_data.size();

            col_data.resize(col_data.size() + length.value);

            uncompressed_slice = Slice(col_data.data() + idx, length.value);

            Slice compressed_data(data.data + COMPRESS_STR_LENGTH, data.size - COMPRESS_STR_LENGTH);

            auto st = compression_codec->decompress(compressed_data, &uncompressed_slice);

            if (!st.ok()) {                                      // is not a legal compressed string

                col_data.resize(col_data.size() - length.value); // remove compressed_data

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

                null_map[row] = true;

                continue;

            }

            col_offset[row] = col_offset[row - 1] + length.value;

        }

        block.replace_by_position(

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

        return Status::OK();

    }

};

void register_function_compress(SimpleFunctionFactory& factory) {

    factory.register_function<FunctionCompress>();

    factory.register_function<FunctionUncompress>();

}

} // namespace doris