using UnityEngine;
using UnityEditor;
using Dreamteck.Splines;
using System.Collections.Generic;

public class SplineSimpleMerge : EditorWindow
{
    [MenuItem("Tools/Splines/Simple Merge Selected Splines")]
    static void ShowWindow() => GetWindow<SplineSimpleMerge>("Merge Splines");

    void OnGUI()
    {
        if (GUILayout.Button("合并选中的 SplineComputer"))
        {
            MergeSplines();
        }
    }

    void MergeSplines()
    {
        var list = new List<SplinePoint>();

        foreach (var transform in Selection.transforms)
        {
            if (!transform.TryGetComponent<SplineComputer>(out var computer)) continue;
            var points = computer.GetPoints();

            for (var i = 0; i < points.Length; i++)
            {
                var splinePoint = points[i];

                // 如果不是第一个段的第一个点，需要平滑衔接前一个点
                if (i == 0 && list.Count > 0)
                {
                    var lastIndex = list.Count - 1;
                    var last = list[lastIndex];

                    // 计算两点之间方向
                    Vector3 dir = (splinePoint.position - last.position).normalized;
                    float distance = Vector3.Distance(splinePoint.position, last.position) * 0.5f;

                    // 设置上一个点的 tangent 和当前点的 tangent2（对称方向）
                    last.tangent2 = last.position + dir * distance;
                    splinePoint.tangent = splinePoint.position - dir * distance;

                    list[lastIndex] = last; // 更新修改过的前一个点
                }

                list.Add(splinePoint);
            }
        }

        if (list.Count == 0)
        {
            Debug.LogWarning("未找到任何 SplineComputer！");
            return;
        }

        // 创建新的合并轨道
        var go = new GameObject("Spline_Merged_Simple");
        var newSpline = go.AddComponent<SplineComputer>();
        newSpline.type = Spline.Type.Bezier;
        newSpline.SetPoints(list.ToArray());

        Debug.Log($"✅ 合并成功，生成 {list.Count} 个 SplinePoint");
    }
}