using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MongoDB.Driver;


using MONGO_DB_LIST = System.String;


namespace ServerCore;


// HANDOVER: MongoDB Wrapper 클래스 이고, MongoDB 연결을 위한 함수를 제공 한다.

public abstract class MongoDbConnectorBase : IDisposable
{
    private IMongoClient? m_mongo_client;

    public MongoDbConnectorBase()
    {
    }

    public async Task<(bool, List<MONGO_DB_LIST>)> initAndVerifyDb( string connectionString
                                                                  , int minConnectionPoolSize, int maxConnectionPoolSize
                                                                  , int waitQueueTimeoutSecs )
    {
        var err_msg = string.Empty;

        try
        {
            if (true == connectionString.isNullOrWhiteSpace())
            {
                throw new ArgumentException("Connection string is null or empty.", nameof(connectionString));
            }

            if (minConnectionPoolSize < 0 || maxConnectionPoolSize <= 0 || minConnectionPoolSize > maxConnectionPoolSize)
            {
                throw new ArgumentOutOfRangeException("Invalid pool size configuration.");
            }

            if (waitQueueTimeoutSecs < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(waitQueueTimeoutSecs), "Wait queue timeout must be non-negative.");
            }

            var settings = MongoClientSettings.FromConnectionString(connectionString);
            settings.MinConnectionPoolSize = minConnectionPoolSize;
            settings.MaxConnectionPoolSize = maxConnectionPoolSize;
            settings.WaitQueueTimeout = TimeSpan.FromSeconds(waitQueueTimeoutSecs);

            var mongo_client = new MongoClient(settings);

            var cursor = await mongo_client.ListDatabaseNamesAsync();
            var db_list = await cursor.ToListAsync();

            m_mongo_client = mongo_client;

            return (true, db_list);
        }
        catch (Exception e)
        {
            Log.getLogger().error($"Exception !!!, Failed to perform in MongoDbConnectorBase.initAndVerifyDb() !!! : exception:{e} - connectionString:{connectionString}");
        }

        return (false, new List<MONGO_DB_LIST>());
    }

    public IMongoClient getMongoClient()
    {
        NullReferenceCheckHelper.throwIfNull(m_mongo_client, () => $"m_mongo_client is null !!!");
        return m_mongo_client;
    }

    public void Dispose()
    {
        m_mongo_client = null;
        GC.SuppressFinalize(this);
    }

    public void disposeMongoDb()
    {
        Dispose();
    }
}