#pragma once

#include <boost/asio.hpp>
#include <boost/asio/awaitable.hpp>
#include <boost/mysql.hpp>
#include <memory>
#include <queue>
#include <string>

class DatabaseManager {
public:
  static DatabaseManager &GetInstance();

  bool Init(boost::asio::io_context &io_context, const std::string &host,
            uint16_t port, const std::string &user, const std::string &password,
            const std::string &db);

  struct UserData {
    std::string nickname;
    uint64_t gold;
    uint32_t swordLevel;
    uint32_t maxSwordLevel;
  };

  struct RankingResult {
    struct Entry {
      uint32_t rank;
      std::string nickname;
      uint64_t value;
    };
    std::vector<Entry> topEntries;
    int32_t myRank;
    uint64_t myValue;
  };

  boost::asio::awaitable<UserData> LoadUser(std::string nickname);
  boost::asio::awaitable<void> SaveUser(std::string nickname, uint64_t gold,
                                        uint32_t swordLevel);
  boost::asio::awaitable<RankingResult> GetRanking(int type,
                                                   std::string nickname);

  //  내부용 객체
  class PooledConnection {
  public:
    PooledConnection(DatabaseManager &manager,
                     std::unique_ptr<boost::mysql::tcp_ssl_connection> conn);
    ~PooledConnection();

    boost::mysql::tcp_ssl_connection &Get();
    boost::mysql::tcp_ssl_connection *operator->();

  private:
    DatabaseManager &manager_;
    std::unique_ptr<boost::mysql::tcp_ssl_connection> conn_;
  };

  boost::asio::awaitable<std::unique_ptr<PooledConnection>> GetConnection();

private:
  DatabaseManager() = default;
  void ReturnConnection(std::unique_ptr<boost::mysql::tcp_ssl_connection> conn);

  // DB 접속 정보 저장용 (새로운 커넥션 생성 시 필요)
  std::string host_, user_, password_, db_;
  uint16_t port_;

  std::unique_ptr<boost::asio::strand<boost::asio::io_context::executor_type>>
      strand_;

  // 풀 상태 관리
  std::vector<std::unique_ptr<boost::mysql::tcp_ssl_connection>>
      available_conns_;
  std::queue<std::shared_ptr<boost::asio::steady_timer>> waiting_queue_;
  const uint16_t max_pool_size_ = 10;
  int16_t current_total_conns_ = 0;
};