using UnityEditor;
using UnityEngine;

[RequireComponent(typeof(CapsuleCollider))]
public class CapsuleColliderGizmo : MonoBehaviour
{
    [Tooltip("Gizmo显示颜色")] public Color gizmoColor = new Color(0, 1, 0, 0.3f);

    [Tooltip("是否始终显示Gizmo")] public bool alwaysShow = true;

    private CapsuleCollider capsuleCollider;

    private void Awake()
    {
        capsuleCollider = GetComponent<CapsuleCollider>();
    }

    private void OnDrawGizmos()
    {
# if UNITY_EDITOR
        if (!alwaysShow && !Selection.Contains(gameObject)) return;
#endif
        DrawCapsuleGizmo();
    }

    private void OnDrawGizmosSelected()
    {
        if (alwaysShow) return;
        DrawCapsuleGizmo();
    }

    private void DrawCapsuleGizmo()
    {
        if (capsuleCollider == null)
        {
            capsuleCollider = GetComponent<CapsuleCollider>();
            if (capsuleCollider == null) return;
        }

        Gizmos.color = gizmoColor;

        // 获取胶囊体的参数
        Vector3 center = transform.TransformPoint(capsuleCollider.center);
        float radius = capsuleCollider.radius * Mathf.Max(transform.lossyScale.x, transform.lossyScale.z);
        float height = capsuleCollider.height * transform.lossyScale.y;
        int direction = capsuleCollider.direction;

        // 计算胶囊体的两个半球中心
        Vector3 halfHeight = Vector3.zero;
        switch (direction)
        {
            case 0: // X轴
                halfHeight = Vector3.right * (height / 2 - radius);
                radius = capsuleCollider.radius * Mathf.Max(transform.lossyScale.y, transform.lossyScale.z);
                break;
            case 1: // Y轴
                halfHeight = Vector3.up * (height / 2 - radius);
                radius = capsuleCollider.radius * Mathf.Max(transform.lossyScale.x, transform.lossyScale.z);
                break;
            case 2: // Z轴
                halfHeight = Vector3.forward * (height / 2 - radius);
                radius = capsuleCollider.radius * Mathf.Max(transform.lossyScale.x, transform.lossyScale.y);
                break;
        }

        Vector3 topCenter = center + halfHeight;
        Vector3 bottomCenter = center - halfHeight;

        // 绘制胶囊体的圆柱部分
        if (height > radius * 2)
        {
            DrawCylinder(topCenter, bottomCenter, radius, 16);
        }

        // 绘制上下两个半球
        Gizmos.DrawSphere(topCenter, radius);
        Gizmos.DrawSphere(bottomCenter, radius);
    }

    // 添加自定义圆柱绘制方法
    private void DrawCylinder(Vector3 topCenter, Vector3 bottomCenter, float radius, int segments)
    {
        Vector3 up = (topCenter - bottomCenter).normalized;
        Vector3 right = Vector3.Cross(up, Vector3.forward).normalized;
        if (right.sqrMagnitude < 0.01f)
            right = Vector3.Cross(up, Vector3.right).normalized;
        Vector3 forward = Vector3.Cross(up, right).normalized;

        for (int i = 0; i < segments; i++)
        {
            float angle = (i / (float)segments) * Mathf.PI * 2;
            float nextAngle = ((i + 1) / (float)segments) * Mathf.PI * 2;

            Vector3 topPoint = topCenter + (Mathf.Cos(angle) * right + Mathf.Sin(angle) * forward) * radius;
            Vector3 topNextPoint = topCenter + (Mathf.Cos(nextAngle) * right + Mathf.Sin(nextAngle) * forward) * radius;
            Vector3 bottomPoint = bottomCenter + (Mathf.Cos(angle) * right + Mathf.Sin(angle) * forward) * radius;
            Vector3 bottomNextPoint =
                bottomCenter + (Mathf.Cos(nextAngle) * right + Mathf.Sin(nextAngle) * forward) * radius;

            // 绘制侧面竖线
            Gizmos.DrawLine(topPoint, bottomPoint);
            // 绘制顶部环线
            Gizmos.DrawLine(topPoint, topNextPoint);
            // 绘制底部环线
            Gizmos.DrawLine(bottomPoint, bottomNextPoint);
        }
    }
}