TimedAction.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;

[System.Serializable]
public class TimedAction {

	public DateTime time_started { get; private set; }
	public float duration { get; private set; }
	public double action_ratio { get; private set; } // 0 to 1.
    private double time_progress;
    private double delta;
	private DateTime _last_date = DateTime.Now;

	public TimedAction(float duration, DateTime date)
	{
		this.time_started = date;
		this.duration = duration;
	}

	public void Update(DateTime new_date)
	{
		delta = MsElapsed (new_date, _last_date);
		this.time_progress += delta/1000f;
		action_ratio = Mathf.Min ((float)time_progress / duration, 1f);
		_last_date = new_date;
	}
		
	private double MsElapsed(DateTime a, DateTime b)
	{
		return a.Subtract(b).TotalMilliseconds;
	}

	public string SerializeToJSON()
	{
        TimedActionStruct s;
        s.time_started = this.time_started.ToFileTimeUtc();
        s.duration = this.duration;
        s._last_date = this._last_date.ToFileTimeUtc();
        string json = JsonUtility.ToJson(s, true);
		return json; // TODO: Display the content of the string.
	}
}

[Serializable]
public struct TimedActionStruct {
    public long time_started;
    public float duration;
    // public double action_ratio; Calculable avec: time_progress / duration
    // public double time_progress; Calculable avec: delta/1000 * msElapsed(new_date, _last_date)
    // public double delta; Calculable avec le _last_date;
    public long _last_date;

}