// 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/FunctionsMultiStringSearch.h

// and modified by Doris

#pragma once

#include <hs/hs_runtime.h>

#include <algorithm>

#include <cstddef>

#include <limits>

#include <memory>

#include <optional>

#include <vector>

#include "common/status.h"

#include "core/column/column_array.h"

#include "core/column/column_nullable.h"

#include "core/column/column_string.h"

#include "core/data_type/data_type_number.h"

#include "core/field.h"

#include "core/pod_array_fwd.h"

#include "core/string_ref.h"

#include "core/types.h"

#include "exprs/function/function_helpers.h"

#include "exprs/function/regexps.h"

namespace doris {

/// For more readable instantiations of MultiMatchAnyImpl<>

struct MultiMatchTraits {

    enum class Find { Any, AnyIndex };

};

template <PrimitiveType PType, MultiMatchTraits::Find Find, bool WithEditDistance>

struct FunctionMultiMatchAnyImpl {

    using ResultType = typename PrimitiveTypeTraits<PType>::CppType;

    static constexpr PrimitiveType ResultPType = PType;

    static constexpr bool FindAny = (Find == MultiMatchTraits::Find::Any);

    static constexpr bool FindAnyIndex = (Find == MultiMatchTraits::Find::AnyIndex);

    static constexpr auto name = "multi_match_any";

    static auto get_return_type() {

        return std::make_shared<typename PrimitiveTypeTraits<PType>::DataType>();

    }

    /**

     * Prepares the regular expressions and scratch space for Hyperscan.

     *

     * This function takes a vector of needles (substrings to search for) and initializes

     * the regular expressions and scratch space required for Hyperscan, a high-performance

     * regular expression matching library.

     *

     */

    static Status prepare_regexps_and_scratch(const std::vector<StringRef>& needles,

                                              multiregexps::RegexpsPtr& regexps,

                                              multiregexps::ScratchPtr& smart_scratch) {

        multiregexps::DeferredConstructedRegexpsPtr deferred_constructed_regexps =

                multiregexps::getOrSet</*SaveIndices*/

                                       FindAnyIndex, WithEditDistance>(needles, std::nullopt);

        regexps = deferred_constructed_regexps->get();

        hs_scratch_t* scratch = nullptr;

        hs_error_t err = hs_clone_scratch(regexps->getScratch(), &scratch);

        if (err != HS_SUCCESS) {

            return Status::InternalError("could not clone scratch space for vectorscan");

        }

        smart_scratch.reset(scratch);

        return Status::OK();

    }

    /**

     * Static callback function to handle the match results of the hs_scan function.

     *

     * This function is called when a matching substring is found while scanning with

     * Hyperscan. It updates the result based on the match information.

     *

     */

    static int on_match([[maybe_unused]] unsigned int id, unsigned long long /* from */, // NOLINT

                        unsigned long long /* to */,                                     // NOLINT

                        unsigned int /* flags */, void* context) {

        if constexpr (FindAnyIndex) {

            *reinterpret_cast<ResultType*>(context) = id;

        } else if constexpr (FindAny) {

            *reinterpret_cast<ResultType*>(context) = 1;

        }

        /// Once we hit the callback, there is no need to search for others.

        return 1;

    }

    static Status vector_constant(const ColumnString::Chars& haystack_data,

                                  const ColumnString::Offsets& haystack_offsets,

                                  const Array& needles_arr, PaddedPODArray<ResultType>& res,

                                  PaddedPODArray<UInt64>& offsets, bool allow_hyperscan,

                                  size_t max_hyperscan_regexp_length,

                                  size_t max_hyperscan_regexp_total_length) {

        if (!allow_hyperscan) {

            return Status::InvalidArgument("Hyperscan functions are disabled");

        }

        std::vector<StringRef> needles;

        needles.reserve(needles_arr.size());

        for (const auto& needle : needles_arr) {

            const auto& tmp = needle.get<TYPE_STRING>();

            needles.emplace_back(StringRef {tmp.data(), tmp.size()});

        }

        res.resize(haystack_offsets.size());

        if (needles_arr.empty()) {

            std::fill(res.begin(), res.end(), 0);

            return Status::OK();

        }

        multiregexps::RegexpsPtr regexps;

        multiregexps::ScratchPtr smart_scratch;

        RETURN_IF_ERROR(prepare_regexps_and_scratch(needles, regexps, smart_scratch));

        const size_t haystack_offsets_size = haystack_offsets.size();

        UInt64 offset = 0;

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

            UInt64 length = haystack_offsets[i] - offset;

            /// vectorscan restriction.

            if (length > std::numeric_limits<UInt32>::max()) {

                return Status::InternalError("too long string to search");

            }

            /// zero the result, scan, check, update the offset.

            res[i] = 0;

            hs_error_t err = hs_scan(

                    regexps->getDB(), reinterpret_cast<const char*>(haystack_data.data()) + offset,

                    static_cast<unsigned>(length), 0, smart_scratch.get(), on_match, &res[i]);

            if (err != HS_SUCCESS && err != HS_SCAN_TERMINATED) {

                return Status::InternalError("failed to scan with vectorscan");

            }

            offset = haystack_offsets[i];

        }

        return Status::OK();

    }

    static Status vector_vector(const ColumnString::Chars& haystack_data,

                                const ColumnString::Offsets& haystack_offsets,

                                const IColumn& needles_data,

                                const ColumnArray::Offsets64& needles_offsets,

                                PaddedPODArray<ResultType>& res, PaddedPODArray<UInt64>& offsets,

                                bool allow_hyperscan, size_t max_hyperscan_regexp_length,

                                size_t max_hyperscan_regexp_total_length) {

        if (!allow_hyperscan) {

            return Status::InvalidArgument("Hyperscan functions are disabled");

        }

        res.resize(haystack_offsets.size());

        size_t prev_haystack_offset = 0;

        size_t prev_needles_offset = 0;

        const auto& nested_column =

                assert_cast<const ColumnNullable&>(needles_data).get_nested_column();

        const auto* needles_data_string = check_and_get_column<ColumnString>(nested_column);

        if (!needles_data_string) {

            return Status::InvalidArgument("needles should be string column");

        }

        std::vector<StringRef> needles;

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

            needles.reserve(needles_offsets[i] - prev_needles_offset);

            for (size_t j = prev_needles_offset; j < needles_offsets[i]; ++j) {

                needles.emplace_back(needles_data_string->get_data_at(j));

            }

            if (needles.empty()) {

                res[i] = 0;

                prev_haystack_offset = haystack_offsets[i];

                prev_needles_offset = needles_offsets[i];

                continue;

            }

            multiregexps::RegexpsPtr regexps;

            multiregexps::ScratchPtr smart_scratch;

            RETURN_IF_ERROR(prepare_regexps_and_scratch(needles, regexps, smart_scratch));

            const size_t cur_haystack_length = haystack_offsets[i] - prev_haystack_offset;

            /// vectorscan restriction.

            if (cur_haystack_length > std::numeric_limits<UInt32>::max()) {

                return Status::InternalError("too long string to search");

            }

            /// zero the result, scan, check, update the offset.

            res[i] = 0;

            hs_error_t err = hs_scan(

                    regexps->getDB(),

                    reinterpret_cast<const char*>(haystack_data.data()) + prev_haystack_offset,

                    static_cast<unsigned>(cur_haystack_length), 0, smart_scratch.get(), on_match,

                    &res[i]);

            if (err != HS_SUCCESS && err != HS_SCAN_TERMINATED) {

                return Status::InternalError("failed to scan with vectorscan");

            }

            prev_haystack_offset = haystack_offsets[i];

            prev_needles_offset = needles_offsets[i];

            needles.clear();

        }

        return Status::OK();

    }

};

} // namespace doris