using System;
using System.Net;
using System.Threading;


using GAURD_KEY = System.String;


namespace ServerCore;

//=============================================================================================
// 병렬 프로그래밍 환경에서 특정 로직이 동시에 실행되지 않도록 보호하는 클래스 이다.
//
// author : kangms
// 
//=============================================================================================

public class AtomicGuard : IDisposable
{
    private string m_try_guard_key = string.Empty;
    private string m_using_guard_key = string.Empty;

    private AtomicString? m_guard_key_nullable;
    private AtomicBool? m_atomic_bool_nullable;

    public AtomicGuard(GAURD_KEY guardKey)
    {
        m_try_guard_key = guardKey;
    }

    public AtomicGuard(AtomicString guardKey)
    {
        m_guard_key_nullable = guardKey;
    }

    public AtomicGuard(AtomicString guardKey, AtomicBool atomicBool)
    {
        m_guard_key_nullable = guardKey;
        m_atomic_bool_nullable = atomicBool;
    }

    public bool tryGuard()
    {
        if (null == m_guard_key_nullable)
        {
            var err_msg = $"m_guard_key_nullable is null !!! in tryGuard() - guardKey:{m_try_guard_key}";
            Log.getLogger().error(err_msg);

            return false;
        }

        if(false == m_guard_key_nullable.compareAndSet(string.Empty, m_try_guard_key))
        {
            var err_msg = $"Failed to in compareAndSet() !!! in tryGuard() - guardKey:{m_try_guard_key}";
            Log.getLogger().info(err_msg);

            return false;
        }

        if (null == m_atomic_bool_nullable)
        {
            var err_msg = $"m_atomic_bool_nullable is null !!! in tryGuard() - guardKey:{m_try_guard_key}";
            Log.getLogger().error(err_msg);

            return false;
        }

        if (false == m_atomic_bool_nullable.set(true))
        {
            var err_msg = $"Failed to set true !!! in tryGuard() - guardKey:{m_try_guard_key}";
            Log.getLogger().info(err_msg);

            return false;
        }

        m_using_guard_key = m_try_guard_key;

        return true;
    }

    public void Dispose()
    {
        if (null == m_guard_key_nullable)
        {
            var err_msg = $"m_guard_key_nullable is null !!! in Dispose() - guardKey:{m_try_guard_key}";
            Log.getLogger().error(err_msg);

            return;
        }

        var guard_key = m_guard_key_nullable.Value;

        if (false == m_guard_key_nullable.compareAndSet(m_using_guard_key, string.Empty))
        {
            var err_msg = $"Failed to compareAndSet() !!! in Dispose() : usingGuardKey:{m_using_guard_key} - guardKey:{guard_key}";
            Log.getLogger().info(err_msg);

            return;
        }

        if (null == m_atomic_bool_nullable)
        {
            var err_msg = $"m_atomic_bool_nullable is null !!! in Dispose() - guardKey:{guard_key}";
            Log.getLogger().error(err_msg);

            return;
        }

        if (false == m_atomic_bool_nullable.set(false))
        {
            var err_msg = $"Failed to set false in Dispose() !!! - guardKey:{guard_key}";
            Log.getLogger().error(err_msg);

            return;
        }
    }

    public void bindAtomic(AtomicString guardKey, AtomicBool atomicBool)
    {
        m_guard_key_nullable = guardKey;
        m_atomic_bool_nullable = atomicBool;
    }
}