// Perfect Culling (C) 2021 Patrick König
//

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

namespace Koenigz.PerfectCulling
{
    public static class CustomHandle
    {
        public interface IResizableByHandle
        {
            Vector3 HandleSized { get; set; }
        }

        public class ActualHandle<T, U> where T : UnityEngine.Behaviour, IResizableByHandle
            where U : struct
        {
#if UNITY_EDITOR
            public void DrawHandle(T zone)
            {
                Matrix4x4 oldMatrix = Handles.matrix;

                Matrix4x4 mat = Matrix4x4.TRS(zone.transform.position, zone.transform.rotation, Vector3.one);

                Handles.matrix = mat;

                DrawHandleForDirection(zone, mat, Vector3.up);
                DrawHandleForDirection(zone, mat, -Vector3.up);

                DrawHandleForDirection(zone, mat, Vector3.right);
                DrawHandleForDirection(zone, mat, -Vector3.right);

                DrawHandleForDirection(zone, mat, Vector3.forward);
                DrawHandleForDirection(zone, mat, -Vector3.forward);

                Handles.matrix = oldMatrix;
            }

            void DrawHandleForDirection(T origin, Matrix4x4 matrix4X4, Vector3 axis)
            {
                Vector3 oldSize = origin.HandleSized;

                Vector3 snap = Vector3.one * 0.5f;

                Vector3 GetAxis(Vector3 value) => Vector3.Scale(value, axis);

                Transform t = origin.transform;

                Vector3 basePos = (0.5f * Vector3.Scale(origin.HandleSized, axis));

                float size = UnityEditor.HandleUtility.GetHandleSize(basePos) * 0.1f;

                UnityEditor.EditorGUI.BeginChangeCheck();

#if UNITY_2022_1_OR_NEWER
                Vector3 hPos3 = UnityEditor.Handles.FreeMoveHandle(basePos, size, snap, UnityEditor.Handles.DotHandleCap);
#else
                Vector3 hPos3 = UnityEditor.Handles.FreeMoveHandle(basePos, Quaternion.identity, size, snap,
                    UnityEditor.Handles.DotHandleCap);
#endif

                if (UnityEditor.EditorGUI.EndChangeCheck())
                {
                    string undoName = "Size changed";

                    UnityEditor.Undo.RecordObject(origin, undoName);
                    UnityEditor.Undo.RecordObject(origin.transform, undoName);

                    if (axis.x < 0 || axis.y < 0 || axis.z < 0)
                    {
                        Vector3 tmp = (GetAxis(basePos) - GetAxis(hPos3));

                        tmp.x = GetValue(tmp.x);
                        tmp.y = GetValue(tmp.y);
                        tmp.z = GetValue(tmp.z);

                        origin.HandleSized = origin.HandleSized - tmp;

                        if (GetAxis(origin.HandleSized).magnitude <= 1)
                        {
                            origin.HandleSized = oldSize;
                        }
                        else
                        {
                            t.Translate(0.5f * tmp);
                        }
                    }
                    else
                    {
                        Vector3 tmp = (GetAxis(hPos3) - GetAxis(basePos));

                        tmp.x = GetValue(tmp.x);
                        tmp.y = GetValue(tmp.y);
                        tmp.z = GetValue(tmp.z);

                        origin.HandleSized = origin.HandleSized + tmp;

                        if (GetAxis(origin.HandleSized).magnitude <= 1)
                        {
                            origin.HandleSized = oldSize;
                        }
                        else
                        {
                            t.Translate(0.5f * tmp);
                        }
                    }
                }
            }

            float GetValue(float x)
            {
                if (typeof(U) == typeof(float))
                {
                    return x;
                }

                if (typeof(U) == typeof(int))
                {
                    return (int)x;
                }

                throw new System.NotImplementedException();
            }
#endif
        }
    }
}