using System.Collections;
using UnityEngine;

// 剣閃シェーダーを使った発展的な攻撃エフェクト
public class SlashEffect : MonoBehaviour
{
    private static readonly int MagId =
        Shader.PropertyToID("_Mag");

    [Tooltip("剣閃エフェクトの広がり方")]
    [SerializeField] private AnimationCurve magnitudeCurve =
        AnimationCurve.Linear(0f, 0f, 1f, 1f);

    [Tooltip("攻撃中だけ表示する剣閃エフェクトのRenderer")]
    [SerializeField] private MeshRenderer slashMeshRenderer;

    private Material _slashMaterial;
    private Coroutine _playCoroutine;

    private void Awake()
    {
        _slashMaterial = slashMeshRenderer.material;

        SetMagnitude(0f);
        SetVisible(false);
    }

    public void Play(float duration)
    {
        if (_playCoroutine != null)
            StopCoroutine(_playCoroutine);

        _playCoroutine =
            StartCoroutine(PlayCoroutine(duration));
    }

    // 再生中の剣閃を停止して初期表示へ戻す
    public void Stop()
    {
        if (_playCoroutine != null)
            StopCoroutine(_playCoroutine);

        _playCoroutine = null;
        SetVisible(false);
        SetMagnitude(0f);
    }

    private IEnumerator PlayCoroutine(float duration)
    {
        SetVisible(true);

        var elapsedTime = 0f;
        while (elapsedTime < duration)
        {
            var progress = elapsedTime / duration;

            SetMagnitude(
                magnitudeCurve.Evaluate(progress));

            elapsedTime += Time.deltaTime;
            yield return null;
        }

        SetMagnitude(magnitudeCurve.Evaluate(1f));
        SetVisible(false);
        SetMagnitude(0f);

        _playCoroutine = null;
    }

    private void SetMagnitude(float value)
    {
        _slashMaterial.SetFloat(MagId, value);
    }

    private void SetVisible(bool isVisible)
    {
        slashMeshRenderer.enabled = isVisible;
    }

    private void OnDisable()
    {
        Stop();
    }

    private void OnDestroy()
    {
        Destroy(_slashMaterial);
    }
}