//
// Created by Kirill Zhukov on 20.04.2025.
//

#ifndef UDB_H
#define UDB_H

#include <string>
#include <unordered_map>
#include <atomic>
#include <thread>
#include <memory>

#include "Memtable.h"
#include "utils/datastructures/LFCircullarBuffer.h"
#include "core/SharedMemoryManager.h"
#include "core/SharedCommandQueue.h"
#include "core/Command.h"
#include "utils/hash/Hash128.h"
#include "utils/datastructures/LFSkipList.h"
#include "utils/string/basic_utils.h"
#include "utils/io/VersionManager.h"
#include "utils/io/Wal.h"
#include "utils/io/SSTableIO.h"
#include "Memtable.h"
#include "utils/io/RecoveryLog.h"
#include "utils/io/Compactor.h"

namespace usub::core
{
    class UDB
    {
    public:
        UDB(const std::string& db_name, const std::string& shm_name, size_t shm_queue_capacity = 1024,
            size_t max_memtable_size = 1024 * 1024, bool create_new = true);

        ~UDB();

        void run();

    private:
        void process_command(const usub::core::Command& cmd);
        void background_flush_worker();
        void recover_from_logs();

    private:
        std::string db_name_;
        std::string shm_name_;
        size_t shm_queue_capacity_;
        size_t max_memtable_size_;

        SharedMemoryManager shm_manager_;
        SharedCommandQueue* command_queue_;

        utils::VersionManager version_manager_;

        shared_storage::MemTableManager<utils::LFSkipList<utils::Hash128, std::string>> memtable_manager_;
        utils::Compactor compactor_;

        std::unordered_map<utils::Hash128, std::string> fast_cache_;

        std::atomic<bool> running_;
        std::thread background_flush_thread_;
    };
}

#endif // UDB_H