using UnityEngine;
using UnityEngine.UI;

namespace Superlazy.UI
{
    public class SLUIFadeCanvasGroup : SLUIOnOffTransition
    {
        public float fadeInTime = 0.3f;
        public float fadeOutTime = 0.3f;

        private CanvasGroup group;
        private float currentAlpha = 0.0f;

        protected override void Validate()
        {
            group = GetComponent<CanvasGroup>();
        }

        protected override void Init()
        {
            if (currentState) currentAlpha = 1.0f;
            else currentAlpha = 0.0f;

            group.alpha = currentAlpha;
        }

        protected override bool OnUpdate(bool forceUpdate = false)
        {
            var result = false;
            if (currentState)
            {
                if (fadeInTime != 0) currentAlpha += Time.unscaledDeltaTime / fadeInTime;
                else currentAlpha = 1.0f;
                if (currentAlpha >= 1.0f)
                {
                    currentAlpha = 1.0f;
                    result = true;
                }
            }
            else
            {
                if (fadeOutTime != 0) currentAlpha -= Time.unscaledDeltaTime / fadeOutTime;
                else currentAlpha = 0.0f;
                if (currentAlpha <= 0.0f)
                {
                    currentAlpha = 0.0f;
                    result = true;
                }
            }

            group.alpha = currentAlpha;

            return result;
        }

        protected override void ForceDisable()
        {
            group.alpha = 0;
        }
    }
}