// 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.

#pragma once

#include <CLucene.h>

#include <gen_cpp/Exprs_types.h>

#include <map>

#include <memory>

#include <string>

#include <unordered_map>

#include <vector>

#include "core/block/block.h"

#include "core/data_type/data_type.h"

#include "core/data_type/data_type_number.h"

#include "core/types.h"

#include "exprs/function/function.h"

#include "storage/index/index_query_context.h"

#include "storage/index/inverted/inverted_index_cache.h"

#include "storage/index/inverted/query_v2/boolean_query/operator_boolean_query.h"

CL_NS_USE(index)

namespace doris {

using namespace doris::segment_v2;

class IndexExecContext;

struct FieldReaderBinding {

    std::string logical_field_name;

    std::string stored_field_name;

    std::wstring stored_field_wstr;

    DataTypePtr column_type;

    InvertedIndexQueryType query_type;

    InvertedIndexReaderPtr inverted_reader;

    std::shared_ptr<lucene::index::IndexReader> lucene_reader;

    std::map<std::string, std::string> index_properties;

    std::string binding_key;

    std::string analyzer_key;

};

class FieldReaderResolver {

public:

    FieldReaderResolver(

            const std::unordered_map<std::string, IndexFieldNameAndTypePair>& data_type_with_names,

            const std::unordered_map<std::string, IndexIterator*>& iterators,

            std::shared_ptr<IndexQueryContext> context,

            const std::vector<TSearchFieldBinding>& field_bindings = {})

            : _data_type_with_names(data_type_with_names),

              _iterators(iterators),

              _context(std::move(context)),

              _field_bindings(field_bindings) {

        // Build lookup maps for quick access

        for (const auto& binding : _field_bindings) {

            if (binding.__isset.is_variant_subcolumn && binding.is_variant_subcolumn) {

                _variant_subcolumn_fields.insert(binding.field_name);

            }

            _field_binding_map[binding.field_name] = &binding;

        }

    }

    Status resolve(const std::string& field_name, InvertedIndexQueryType query_type,

                   FieldReaderBinding* binding);

    // Check if a field is a variant subcolumn

    bool is_variant_subcolumn(const std::string& field_name) const {

        return _variant_subcolumn_fields.count(field_name) > 0;

    }

    const std::vector<std::shared_ptr<lucene::index::IndexReader>>& readers() const {

        return _readers;

    }

    const std::unordered_map<std::string, std::shared_ptr<lucene::index::IndexReader>>&

    reader_bindings() const {

        return _binding_readers;

    }

    const std::unordered_map<std::wstring, std::shared_ptr<lucene::index::IndexReader>>&

    field_readers() const {

        return _field_readers;

    }

    const std::unordered_map<std::string, FieldReaderBinding>& binding_cache() const {

        return _cache;

    }

    IndexIterator* get_iterator(const std::string& field_name) const {

        auto it = _iterators.find(field_name);

        return (it != _iterators.end()) ? it->second : nullptr;

    }

private:

    std::string binding_key_for(const std::string& stored_field_name,

                                InvertedIndexQueryType query_type) const {

        return stored_field_name + "#" + std::to_string(static_cast<int>(query_type));

    }

    const std::unordered_map<std::string, IndexFieldNameAndTypePair>& _data_type_with_names;

    const std::unordered_map<std::string, IndexIterator*>& _iterators;

    std::shared_ptr<IndexQueryContext> _context;

    std::vector<TSearchFieldBinding> _field_bindings;

    std::unordered_map<std::string, const TSearchFieldBinding*> _field_binding_map;

    std::unordered_set<std::string> _variant_subcolumn_fields;

    std::unordered_map<std::string, FieldReaderBinding> _cache;

    std::vector<std::shared_ptr<lucene::index::IndexReader>> _readers;

    std::unordered_map<std::string, std::shared_ptr<lucene::index::IndexReader>> _binding_readers;

    std::unordered_map<std::wstring, std::shared_ptr<lucene::index::IndexReader>> _field_readers;

    // Keep searcher cache handles alive for the resolver's lifetime.

    // This pins cached IndexSearcher entries so extracted IndexReaders remain valid.

    std::vector<segment_v2::InvertedIndexCacheHandle> _searcher_cache_handles;

};

class FunctionSearch : public IFunction {

public:

    static constexpr auto name = "search";

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

    String get_name() const override { return name; }

    bool is_variadic() const override { return true; }

    size_t get_number_of_arguments() const override { return 0; }

    // We manage nulls explicitly for index pushdown only.

    bool use_default_implementation_for_nulls() const override { return false; }

    bool is_use_default_implementation_for_constants() const override { return false; }

    bool use_default_implementation_for_constants() const override { return false; }

    DataTypePtr get_return_type_impl(const DataTypes& /*arguments*/) const override {

        return std::make_shared<DataTypeUInt8>();

    }

    Status execute_impl(FunctionContext* /*context*/, Block& /*block*/,

                        const ColumnNumbers& /*arguments*/, uint32_t /*result*/,

                        size_t /*input_rows_count*/) const override;

    bool can_push_down_to_index() const override { return true; }

    Status evaluate_inverted_index(

            const ColumnsWithTypeAndName& arguments,

            const std::vector<IndexFieldNameAndTypePair>& data_type_with_names,

            std::vector<IndexIterator*> iterators, uint32_t num_rows,

            const InvertedIndexAnalyzerCtx* /*analyzer_ctx*/,

            InvertedIndexResultBitmap& bitmap_result) const override;

    Status evaluate_inverted_index_with_search_param(

            const TSearchParam& search_param,

            const std::unordered_map<std::string, IndexFieldNameAndTypePair>& data_type_with_names,

            std::unordered_map<std::string, IndexIterator*> iterators, uint32_t num_rows,

            InvertedIndexResultBitmap& bitmap_result, bool enable_cache = true) const;

    Status evaluate_inverted_index_with_search_param(

            const TSearchParam& search_param,

            const std::unordered_map<std::string, IndexFieldNameAndTypePair>& data_type_with_names,

            std::unordered_map<std::string, IndexIterator*> iterators, uint32_t num_rows,

            InvertedIndexResultBitmap& bitmap_result, bool enable_cache,

            const IndexExecContext* index_exec_ctx,

            const std::unordered_map<std::string, int>& field_name_to_column_id) const;

    Status evaluate_nested_query(

            const TSearchParam& search_param, const TSearchClause& nested_clause,

            const std::shared_ptr<IndexQueryContext>& context, FieldReaderResolver& resolver,

            uint32_t num_rows, const IndexExecContext* index_exec_ctx,

            const std::unordered_map<std::string, int>& field_name_to_column_id,

            std::shared_ptr<roaring::Roaring>& result_bitmap) const;

    // Public methods for testing

    enum class ClauseTypeCategory {

        NON_TOKENIZED, // TERM, PREFIX, WILDCARD, REGEXP, RANGE, LIST - no tokenization, use EQUAL_QUERY

        TOKENIZED,     // PHRASE, MATCH, ANY, ALL - need tokenization, use MATCH_ANY_QUERY

        COMPOUND       // AND, OR, NOT - boolean operations

    };

    ClauseTypeCategory get_clause_type_category(const std::string& clause_type) const;

    // Analyze query type for a specific field in the search clause

    InvertedIndexQueryType analyze_field_query_type(const std::string& field_name,

                                                    const TSearchClause& clause) const;

    // Map clause_type string to InvertedIndexQueryType

    InvertedIndexQueryType clause_type_to_query_type(const std::string& clause_type) const;

    Status build_query_recursive(const TSearchClause& clause,

                                 const std::shared_ptr<IndexQueryContext>& context,

                                 FieldReaderResolver& resolver,

                                 inverted_index::query_v2::QueryPtr* out, std::string* binding_key,

                                 const std::string& default_operator,

                                 int32_t minimum_should_match) const;

    Status build_leaf_query(const TSearchClause& clause,

                            const std::shared_ptr<IndexQueryContext>& context,

                            FieldReaderResolver& resolver, inverted_index::query_v2::QueryPtr* out,

                            std::string* binding_key, const std::string& default_operator,

                            int32_t minimum_should_match) const;

};

} // namespace doris