typesense/include/facet_index.h

#pragma once

#include "ids_t.h"
#include "tsl/htrie_map.h"
#include <unordered_set>

class facet_index_t {
private:
    struct count_list {
        count_list() = delete;

        ~count_list () = default;

        count_list(const std::string& sv, uint32_t facet_count) {
            facet_value = sv;
            count = facet_count;
        }

        count_list& operator=(count_list& obj) {
            facet_value = obj.facet_value;
            count = obj.count;
            return *this;
        }

        std::string facet_value;
        uint32_t count;
    };

    struct facet_index_struct {
        void* id_list_ptr;
        uint32_t index;

        facet_index_struct() {
            id_list_ptr = nullptr;
            index = UINT32_MAX;
        }

        ~facet_index_struct() {};
    };
    
    struct facet_index_counter {
        tsl::htrie_map<char, facet_index_struct> facet_index_map;
        std::vector<count_list> counter_list;
        bool is_migrated = false;
        
        facet_index_counter() {
            facet_index_map.clear();
            counter_list.clear();
        }

        ~facet_index_counter() {
            for(auto it = facet_index_map.begin(); it != facet_index_map.end(); ++it) {
                ids_t::destroy_list(it.value().id_list_ptr);
            }
    
            facet_index_map.clear();

            counter_list.clear();
        }
    };

    std::map<std::string, facet_index_counter> facet_field_map;
    uint32_t count_index = 0;
    std::unordered_set<std::string> dropped_fields;

public:

    facet_index_t() = default;

    ~facet_index_t();

    uint32_t insert(const std::string& field, const std::string& value, uint32_t id, bool is_string = false);

    void erase(const std::string& field);

    bool contains(const std::string& field);

    size_t get_facet_count(const std::string& field);

    size_t intersect(const std::string& val, const uint32_t* result_ids, int result_id_len,
        int max_facet_count, std::map<std::string, uint32_t>& found, 
        bool is_wildcard_no_filter_query);    
    
    void get_facet_indexes(const std::string& field, std::function<void(uint32_t, uint32_t)> functor);

    bool get_migrated (const std::string& field) const;

    void set_migrated(const std::string& field, bool val);

    void set_dropped(const std::string& field);
};