using UnityEngine;

using System;
using System.Collections;

public class TweenCG : Tween
{
    #region 变量

    protected float Delta;
    protected float Origin;
    protected float Destination;
    protected CanvasGroup Target;
    protected CurveFunctionF Func;

    #endregion

    public TweenCG(CanvasGroup target, float origin, float destination, float duration, bool originActive, bool destActive, Curve curve)
    {
        if (Math.Abs(target.alpha - origin) < 0.0005f)
        {
            InForward = true;
        }
        else if (Math.Abs(target.alpha - destination) < 0.0005f)
        {
            InBackward = true;
        }

        Func = ManaAnim.FunctionDicF[curve];
        Target = target;

        IsForward = false;
        IsBackward = false;

        Delta = destination - origin;
        Origin = origin;
        Duration = duration;
        DestActive = destActive;
        Destination = destination;
        OriginActive = originActive;

        OnForwardStart += () =>
        {
            Target.SetActive(true);
            Target.interactable = false;
        };

        OnForwardFinish += () =>
        {
            Target.SetActive(DestActive);
            Target.interactable = DestActive;
        };

        OnBackwardStart += () =>
        {
            Target.SetActive(true);
            Target.interactable = false;
        };

        OnBackwardFinish += () =>
        {
            Target.SetActive(OriginActive);
            Target.interactable = OriginActive;
        };
    }

    public override void StartForward()
    {
        base.StartForward();

        if (IsBackward)
        {
            Timer = Duration - Timer;
        }
        else
        {
            Target.alpha = Origin;
        }
    }

    public override void StartBackward()
    {
        base.StartBackward();

        if (IsForward)
        {
            Timer = Duration - Timer;
        }
        else
        {
            Target.alpha = Destination;
        }
    }

    public override bool DoForward()
    {
        Timer += Time.fixedDeltaTime;

        if (Timer > Duration)
        {
            Timer = 0;

            Target.alpha = Destination;

            IsForward = false;
            InBackward = true;

            OnForwardFinish.Invoke();

            ManaAnim.TweenForList.Remove(this);

            return true;
        }
        else
        {
            Target.alpha = Func(Timer, Duration, Origin, Delta);

            return false;
        }
    }

    public override bool DoBackward()
    {
        Timer += Time.fixedDeltaTime;

        if (Timer > Duration)
        {
            Timer = 0;

            Target.alpha = Origin;

            IsBackward = false;
            InForward = true;

            OnBackwardFinish.Invoke();

            ManaAnim.TweenBacList.Remove(this);

            return true;
        }
        else
        {
            Target.alpha = Func(Timer, Duration, Destination, -Delta);

            return false;
        }
    }
}