typesense/include/popular_queries.h

#pragma once

#include <string>
#include <vector>
#include <tsl/htrie_map.h>
#include <json.hpp>
#include <atomic>
#include <shared_mutex>

class PopularQueries {
public:
    struct QWithTimestamp {
        std::string query;
        uint64_t timestamp;

        QWithTimestamp(const std::string& query, uint64_t timestamp) : query(query), timestamp(timestamp) {}
    };

    static const size_t QUERY_FINALIZATION_INTERVAL_MICROS = 4 * 1000 * 1000;

private:

    size_t k;
    const size_t max_size;

    // counts aggregated within the current node
    tsl::htrie_map<char, uint32_t> local_counts;
    std::shared_mutex lmutex;

    std::unordered_map<std::string, std::vector<QWithTimestamp>> user_prefix_queries;
    std::shared_mutex umutex;

public:

    PopularQueries(size_t k);

    void add(const std::string& value, const bool live_query, const std::string& user_id,
             uint64_t now_ts_us = 0);

    void compact_user_queries(uint64_t now_ts_us);

    void serialize_as_docs(std::string& docs);

    void reset_local_counts();

    size_t get_k();

    std::unordered_map<std::string, std::vector<QWithTimestamp>> get_user_prefix_queries();

    tsl::htrie_map<char, uint32_t> get_local_counts();
};