using UnityEngine;
using UnityEngine.UI;

namespace Superlazy.UI
{
    public class SLUILayoutScale : SLUIOnOffTransition
    {
        public float onDuration = 0.3f;
        public float offDuration = 0.3f;

        public Vector2 startSize = Vector2.one;
        public Vector2 endSize = Vector2.zero;

        private float currentTime;

        private LayoutElement layoutElement;

        protected override void Validate()
        {
            layoutElement = GetComponent<LayoutElement>();
        }

        protected override void Init()
        {
            if (currentState == false)
            {
                currentTime = 0;
            }
            else
            {
                currentTime = 1;
            }

            var current = currentTime == 1 ? startSize : endSize;

            layoutElement.preferredWidth = current.x;
            layoutElement.preferredHeight = current.y;
        }

        protected override bool OnUpdate(bool forceUpdate = false)
        {
            var result = false;

            if (currentState)
            {
                if (onDuration == 0)
                {
                    currentTime = 1;
                }
                else
                {
                    currentTime += Time.unscaledDeltaTime / onDuration;
                }

                if (currentTime >= 1.0f)
                {
                    currentTime = 1.0f;
                    result = true;
                }
            }
            else
            {
                if (offDuration == 0)
                {
                    currentTime = 0;
                }
                else
                {
                    currentTime -= Time.unscaledDeltaTime / offDuration;
                }

                if (currentTime <= 0.0f)
                {
                    currentTime = 0.0f;
                    result = true;
                }
            }

            var ease = currentTime == 1.0f ? 1 :
                        currentState ? 1 - Mathf.Pow(2, -10 * currentTime)
                                     : Mathf.Pow(2, -10 * (1 - currentTime));

            var current = Vector2.Lerp(endSize, startSize, ease);

            layoutElement.preferredWidth = current.x;
            layoutElement.preferredHeight = current.y;

            return result;
        }

        protected override void ForceDisable()
        {
            currentTime = 0.0f;
            layoutElement.preferredWidth = endSize.x;
            layoutElement.preferredHeight = endSize.y;
        }
    }
}