using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Reflection;
using System.Xml.Linq;



namespace ServerCore;

//=============================================================================================
// 주기적 Task 타이머 클래스 이다.
//
// author : kangms
// 
//=============================================================================================

public class PeriodicTaskTimer : IAsyncDisposable
{
    private readonly string m_name;
	private readonly System.Threading.PeriodicTimer m_timer;
	private readonly Task m_timer_task;
	private readonly CancellationTokenSource m_cts;

	public delegate Task FnFunction();
	private readonly FnFunction m_fn_alarm_function;

	public PeriodicTaskTimer(string name, Int32 intervalSec, FnFunction fnAlarmFunction)
	{
        m_name = name;
        m_cts = new CancellationTokenSource();

		m_timer = new System.Threading.PeriodicTimer(TimeSpan.FromSeconds(intervalSec));

		m_fn_alarm_function = fnAlarmFunction;
		m_timer_task = handleTimerAsync(m_timer, m_cts.Token);
	}

    //=============================================================================================
    // CancellationTokenSource 를 외부에서 제어할 때 사용한다.
    //=============================================================================================
    public PeriodicTaskTimer(string name, double intervalMSec, CancellationTokenSource cts, FnFunction fnAlarmFunction)
    {
        m_name = name;
        m_cts = cts;

        m_timer = new System.Threading.PeriodicTimer(TimeSpan.FromMilliseconds(intervalMSec));

        m_fn_alarm_function = fnAlarmFunction;
        m_timer_task = handleTimerAsync(m_timer, m_cts.Token);
    }

    private async Task handleTimerAsync(System.Threading.PeriodicTimer timer, CancellationToken cancel = default)
	{
		try
		{
			while (await timer.WaitForNextTickAsync(cancel))
			{
				await Task.Run(() => m_fn_alarm_function.Invoke());
			}
		}
		catch (OperationCanceledException e)
		{
            var msg = $"PeriodicTaskTimer cancel Operation !!! : exception:{e} - {m_name}";
            Log.getLogger().info(msg);
        }
		catch (Exception e)
		{
			var err_msg = $"PeriodicTaskTimer exception !!! : exception:{e} - {m_name}";
			Log.getLogger().error(err_msg);
		}
	}

	public void cancelTimer() => m_cts.Cancel();

    //for IAsyncDisposable.DisposeAsync()
    public async ValueTask DisposeAsync()
	{
		m_timer.Dispose();
		await m_timer_task;

		GC.SuppressFinalize(this);
	}

	public System.Threading.PeriodicTimer getPeriodicTimer() => m_timer;

	public Task getTask() => m_timer_task;
}


//=============================================================================================
// 주기적 Task 타이머 지원 클래스 이다.
//
// author : kangms
// 
//=============================================================================================
public static class PeriodicTaskHelper
{
    public static async Task runTask(Func<Task> action, TimeSpan interval, CancellationToken cancellationToken = default)
    {
        using var timer = new PeriodicTimer(interval);
        while (cancellationToken.IsCancellationRequested == false)
        {
            try
            {
                await action();
                await timer.WaitForNextTickAsync(cancellationToken);
            }
            catch (OperationCanceledException e)
            {
                var msg = $"PeriodicTaskHelper cancel Operation !!! : Msg:{e.Message}";
                Log.getLogger().info(msg);
                break;
            }
            catch (Exception e)
            {
                var err_msg = $"PeriodicTaskHelper exception !!! : errMsg:{e.Message}";
                Log.getLogger().error(err_msg);
                throw;
            }
        }
    }

    public static void bindToTasks(this PeriodicTaskTimer taskTimer, List<Task> tasks)
    {
        tasks.Add(taskTimer.getTask());
    }
}