// 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 std::shared_ptr<IndexQueryContext>& index_query_context = nullptr) 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