#nullable enable

using System.Collections;
using UnityEngine;

namespace ReplacedPerson.Runtime
{
    [DisallowMultipleComponent]
    public sealed class ReplacedScreenMotion : MonoBehaviour
    {
        private CanvasGroup? _group;
        private Coroutine? _animation;

        public void Play()
        {
            if (_group == null) _group = GetComponent<CanvasGroup>() ?? gameObject.AddComponent<CanvasGroup>();
            if (_animation != null) StopCoroutine(_animation);
            _animation = StartCoroutine(Animate());
        }

        private IEnumerator Animate()
        {
            if (_group == null) yield break;
            _group.alpha = 0f;
            transform.localScale = Vector3.one * .985f;
            const float duration = .22f;
            var elapsed = 0f;
            while (elapsed < duration)
            {
                elapsed += Time.unscaledDeltaTime;
                var t = Mathf.Clamp01(elapsed / duration);
                var eased = 1f - Mathf.Pow(1f - t, 3f);
                _group.alpha = eased;
                transform.localScale = Vector3.one * Mathf.Lerp(.985f, 1f, eased);
                yield return null;
            }
            _group.alpha = 1f;
            transform.localScale = Vector3.one;
            _animation = null;
        }

        private void OnDisable()
        {
            if (_animation != null) StopCoroutine(_animation);
            _animation = null;
            if (_group != null) _group.alpha = 1f;
            transform.localScale = Vector3.one;
        }
    }
}