using Cysharp.Threading.Tasks;
using UnityEngine;
using UnityEngine.VFX;

namespace DanieleMarotta.RiversongCodeShowcase
{
    public class BuildingUpgradeAnimation : MonoBehaviour
    {
        [SerializeField]
        private VisualEffect _vfxPrefab;

        [SerializeField]
        private float _stretchDuration = 0.25f;

        [SerializeField]
        private float _stretchFactor = 1.2f;

        [SerializeField]
        private float _settleDuration = 0.75f;

        [SerializeField]
        private float _settleElasticity = 4.5f;

        public async UniTask PlayAsync(Building building)
        {
            var vfx = Instantiate(_vfxPrefab, transform.position, transform.rotation);
            DustVfxProperties.Setup(vfx, 1, new Vector2(building.Rect.Width, building.Rect.Height));

            var fromScale = transform.localScale;
            var toScale = new Vector3(fromScale.x, fromScale.y * _stretchFactor, fromScale.z);

            var elapsed = 0f;
            while (elapsed < _stretchDuration)
            {
                elapsed += Time.unscaledDeltaTime;
                var t = EaseOutBack(Mathf.Clamp01(elapsed / _stretchDuration));
                transform.localScale = Vector3.LerpUnclamped(fromScale, toScale, t);
                await UniTask.NextFrame();
            }

            elapsed = 0;
            while (elapsed < _settleDuration)
            {
                elapsed += Time.unscaledDeltaTime;
                var t = EaseOutElastic(Mathf.Clamp01(elapsed / _settleDuration), _settleElasticity);
                transform.localScale = Vector3.LerpUnclamped(toScale, fromScale, t);
                await UniTask.NextFrame();
            }

            transform.localScale = fromScale;
        }

        private static float EaseOutBack(float t)
        {
            const float c1 = 1.70158f;
            const float c3 = c1 + 1;
            return 1 + c3 * Mathf.Pow(t - 1, 3) + c1 * Mathf.Pow(t - 1, 2);
        }

        private static float EaseOutElastic(float t, float elasticity)
        {
            var c4 = 2 * Mathf.PI / elasticity;
            return t switch
            {
                0 => 0,
                1 => 1,
                _ => Mathf.Pow(2, -10 * t) * Mathf.Sin((10 * t - 0.75f) * c4) + 1
            };
        }
    }
}