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



namespace ServerCore;

//=============================================================================================
// 간단한 로직을 위한 타이머 클래스 이다.
//
// author : kangms
// 
//=============================================================================================

public class SimpleTimer
{
	private DateTime m_begin_timestamp = DateTime.MinValue;
	private DateTime m_end_timestamp = DateTime.MinValue;

	private Int64 m_time_limit_msec = 0;

	private bool m_is_paused = false;
	private DateTime m_pause_timestamp = new DateTime();
	private Int64 m_pause_total_msec = 0;

	private bool m_active = false;

	public SimpleTimer()
	{
	}

	public SimpleTimer(Int64 timeLimitMSec)
	{
		setTimeLimitMSec(timeLimitMSec);
	}

	public void setTimer(Int64 timeLimitMSec)
	{
		setTimer(0, timeLimitMSec);
	}

	public void setTimer(Int64 beginUtcTick, Int64 timeLimitMSec)
	{
		m_begin_timestamp = beginUtcTick > 0 ? new DateTime(beginUtcTick) : DateTime.UtcNow;
		m_time_limit_msec = timeLimitMSec;

		m_is_paused = false;
		m_pause_total_msec = 0;

		m_end_timestamp = DateTime.MinValue;
	}

	public void activate(Int64 timeLimitMSec = 0)
	{
		m_active = true;
		if (timeLimitMSec != 0)
		{
			setTimer(0, timeLimitMSec);
		}
		else
		{
			reset(0);
		}
	}

	public void activate(Int64 beginUtcTick, Int64 timeLimitMSec = 0)
	{
		m_active = true;
		if (timeLimitMSec != 0)
		{
			setTimer(beginUtcTick, timeLimitMSec);
		}
		else
		{
			reset(beginUtcTick);
		}
	}

	public bool isActive()
	{
		return m_active;
	}

	public void deactivate()
	{
		m_active = false;
		m_end_timestamp = DateTime.UtcNow;
	}

	public void setTimeLimitMSec(Int64 limitMSec)
	{
		m_time_limit_msec = limitMSec;

		m_time_limit_msec = Math.Max(m_time_limit_msec, 0);
	}

	public void incTimeLimitMSec(Int64 incMSec)
	{
		m_time_limit_msec += incMSec;

		m_time_limit_msec = Math.Max(m_time_limit_msec, 0);
	}

	public Int64 getTimeLimitMSec()
	{
		return m_time_limit_msec;
	}

	public void reset()
	{
		setTimer(m_time_limit_msec);
	}

	public void reset(Int64 beginUtcTick)
	{
		setTimer(beginUtcTick, m_time_limit_msec);
	}

	public bool expired()
	{
		if (false == isActive())
		{
			return false;
		}

		if (true == isPause())
		{
			return false;
		}

		return (DateTime.UtcNow - m_begin_timestamp).TotalMilliseconds > (m_pause_total_msec + m_time_limit_msec);
	}

	public void pause()
	{
		if (isPause())
		{
			return;
		}

		m_is_paused = true;
		m_pause_timestamp = DateTime.UtcNow;
	}

	public bool isPause()
	{
		return m_is_paused;
	}

	public void unpause()
	{
		if (false == isPause())
		{
			return;
		}

		var pause_time = (DateTime.UtcNow - m_pause_timestamp).TotalMilliseconds;
		m_pause_total_msec += (Int64)pause_time;

		m_is_paused = false;
	}

	public Int64 getTotalTimeMSec()
	{
		if (!isActive())
		{
			return 0;
		}

		var end_time = m_begin_timestamp.AddMilliseconds(m_time_limit_msec);

		var total_time = (end_time - m_begin_timestamp).TotalMilliseconds;

		total_time = Math.Max(total_time, 0);

		return (Int64)total_time;
	}

	public Int64 getElapsedPauseTimeMSec()
	{
		if (false == isActive())
		{
			return 0;
		}

		var pause_time = m_pause_total_msec;

		if (true == isPause())
		{
			pause_time += (Int64)((DateTime.UtcNow - m_pause_timestamp).TotalMilliseconds);
		}

		pause_time = Math.Max(pause_time, 0);

		return (Int64)pause_time;
	}

	public bool isOn()
	{
		if (false == expired())
		{
			return false;
		}

		reset();

		return true;
	}

	public DateTime getStartedTime() => m_begin_timestamp;
	public DateTime getEndTime() => m_end_timestamp;

	public Int64 getRemainTimeMSec()
	{
		if (false == isActive())
		{
			return 0;
		}

		var pause_time = getElapsedPauseTimeMSec();

		TimeSpan time_span = DateTime.UtcNow - m_begin_timestamp;
		var remain_time = m_time_limit_msec + pause_time - (Int64)time_span.TotalMilliseconds;
		remain_time = Math.Max(remain_time, 0);

		return remain_time;
	}

	public Int64 getElapsedTimeMSec()
	{
		if (false == isActive())
		{
			return 0;
		}

		TimeSpan time_span = DateTime.UtcNow - m_begin_timestamp;
		return (Int64)time_span.TotalMilliseconds;
	}

}