#if UNITY_EDITOR
using System;
using UnityEditor;
using UnityEditorInternal;
using UnityEngine;
using UnityEngine.UIElements;

namespace TweenAnimation
{
    [CustomEditor(typeof(TweenPath))]
    public class TweenPathEditor : Editor
    {
        TweenPath tweenPath;
        ReorderableList targetsList;
        int selectIndex = -1;
        private AnimationCurve inverseSpeedCurve;
        float startPos = 0f;

        SerializedProperty targetsProp;

        public override VisualElement CreateInspectorGUI()
        {
            tweenPath = (target as TweenPath);
            targetsProp = serializedObject.FindProperty("targets");
            targetsList = new ReorderableList(serializedObject, targetsProp, true, true, true, true);
            targetsList.onSelectCallback += (_) =>
            {
                if (selectIndex == targetsList.index)
                {
                    targetsList.ClearSelection();
                    selectIndex = -1;
                }
                else
                {
                    selectIndex = targetsList.index;
                    var target = tweenPath.targets[selectIndex];
                    startPos = Time2StartPos(target.startPos);
                }
            };
            targetsList.drawHeaderCallback = DrawHeader;

            targetsList.drawElementCallback = DrawListItems;
            targetsList.displayAdd = false;

            inverseSpeedCurve = new AnimationCurve();
            for (int i = 0; i < tweenPath.speedCurve.length; i++)
            {

                float inWeight = (tweenPath.speedCurve.keys[i].inTangent * tweenPath.speedCurve.keys[i].inWeight);
                float outWeight = (tweenPath.speedCurve.keys[i].outTangent * tweenPath.speedCurve.keys[i].outWeight);

                Keyframe inverseKey = new Keyframe(tweenPath.speedCurve.keys[i].value, tweenPath.speedCurve.keys[i].time, 1 / tweenPath.speedCurve.keys[i].inTangent, 1 / tweenPath.speedCurve.keys[i].outTangent, inWeight, outWeight);

                inverseSpeedCurve.AddKey(inverseKey);
            }

            return base.CreateInspectorGUI();
        }

        private void DrawListItems(Rect rect, int index, bool isActive, bool isFocused)
        {
            if (index < 0)
            {
                return;
            }

            EditorGUI.PropertyField(rect, targetsProp.GetArrayElementAtIndex(index).FindPropertyRelative("transform"));
        }

        private void DrawHeader(Rect rect)
        {
            string name = "目标物体";
            EditorGUI.LabelField(rect, name);
        }

        private void UpdateTargets()
        {
            if (targetsProp.arraySize != tweenPath.transform.childCount)
            {
                var tr = tweenPath.transform;
                if (tweenPath.transform.childCount > targetsProp.arraySize)
                {
                    var cnt = tweenPath.transform.childCount - targetsProp.arraySize;
                    for (int i = 0; i < cnt; i++)
                    {
                        targetsProp.InsertArrayElementAtIndex(targetsProp.arraySize);
                        targetsProp.GetArrayElementAtIndex(targetsProp.arraySize - 1).managedReferenceValue = new TweenPath.TweenTarget();
                    }
                }
                serializedObject.ApplyModifiedProperties();

                for (int i = 0; i < targetsProp.arraySize; i++)
                {
                    var target = targetsProp.GetArrayElementAtIndex(i).managedReferenceValue as TweenPath.TweenTarget;
                    if (target == null)
                    {
                        targetsProp.GetArrayElementAtIndex(i).managedReferenceValue = new TweenPath.TweenTarget()
                        {
                            transform = tr.GetChild(i),
                            startPos = 0
                        };
                    }
                    else if (target.transform && target.transform.parent != tweenPath.transform)
                    {
                        targetsProp.DeleteArrayElementAtIndex(i);
                    }
                    else if (target.transform != tr.GetChild(i))
                    {
                        target.transform = tr.GetChild(i);
                        target.startPos = 0;
                    }
                }
            }
            else
            {
                if (tweenPath.targets == null)
                {
                    return;
                }

                Array.Sort(tweenPath.targets, (a, b) =>
                {
                    var ai = 0;
                    var bi = 0;
                    for (int i = 0; i < tweenPath.transform.childCount; i++)
                    {
                        if (tweenPath.transform.GetChild(i) == a.transform)
                        {
                            ai = i;
                        }
                        if (tweenPath.transform.GetChild(i) == b.transform)
                        {
                            bi = i;
                        }
                    }

                    return ai.CompareTo(bi);
                });

            }

            serializedObject.ApplyModifiedProperties();
        }

        public override void OnInspectorGUI()
        {
            serializedObject.Update();
            UpdateTargets();

            base.OnInspectorGUI();
            targetsList.DoLayoutList();
            serializedObject.ApplyModifiedProperties();
        }

        public void OnSceneGUI()
        {
            if (selectIndex == -1)
            {
                tweenPath.isEditing = false;
                Tools.hidden = false;
                return;
            }
            Tools.hidden = true;
            tweenPath.isEditing = true;
            DrawSelectHandle();
        }


        private void DrawSelectHandle()
        {
            var target = tweenPath.targets[selectIndex];

            target.transform.localPosition = tweenPath.path.EvaluateLocalPosition(startPos);
            var newPos = Handles.PositionHandle(target.transform.position, Quaternion.identity);
            startPos = tweenPath.path.FindClosestPoint(newPos, 0, 1, 1000);

            target.startPos = StartPos2Time(startPos);
        }

        private float Time2StartPos(float t)
        {
            var p = tweenPath.speedCurve.Evaluate(t);
            p = p * (tweenPath.path.MaxPos - tweenPath.path.MinPos);
            return p;
        }

        private float StartPos2Time(float pos)
        {
            var t = pos / (tweenPath.path.MaxPos - tweenPath.path.MinPos);
            t = inverseSpeedCurve.Evaluate(t);
            return t;
        }

        private void OnDestroy()
        {
            Tools.hidden = false;
        }
    }
}
#endif