using OpenTK.Mathematics;

namespace Yw.WinFrmUI.Hydro
{
    /// <summary>
    /// 2d正交相机
    /// </summary>
    internal class OrthoCamera2d
    {
        /// <summary>
        /// 辅助类
        /// </summary>
        public OrthoCamera2d() { }

        /// <summary>
        /// 旋转
        /// </summary>
        public Vector3 Rotation
        {
            get => _rotation;
            set => _rotation = value;
        }
        private Vector3 _rotation = Vector3.Zero;

        /// <summary>
        /// 平移
        /// </summary>
        public Vector3 Translation
        {
            get => _translation;
            set => _translation = value;
        }
        private Vector3 _translation = Vector3.Zero;

        /// <summary>
        /// 投影矩阵
        /// </summary>
        public Matrix4 ProjectionMatrix
        {
            get => _projectionMatrix;
            set => _projectionMatrix = value;
        }
        private Matrix4 _projectionMatrix = Matrix4.Identity;

        /// <summary>
        /// 视图矩阵
        /// </summary>
        public Matrix4 ViewMatrix
        {
            get => _viewMatrix;
            set => _viewMatrix = value;
        }
        private Matrix4 _viewMatrix = Matrix4.Identity;

        /// <summary>
        /// 模型矩阵
        /// </summary>
        public Matrix4 ModelMatrix
        {
            get => _modelMatrix;
            set => _modelMatrix = value;
        }
        private Matrix4 _modelMatrix = Matrix4.Identity;

        /// <summary>
        /// 缩放
        /// </summary>
        public float Zoom
        {
            get => _zoom;
            set => _zoom = MathHelper.Clamp(value, 0.01f, 100.0f); // 限制缩放范围
        }
        private float _zoom = 1.0f; // 当前缩放系数（1表示原始大小）

        private BoundingBox3 _bx = null;
        private Vector3 _center = Vector3.Zero;
        private float _radius = 100f;//包围球半径
        private float _width, _height, _aspect;//视口宽度和高度与宽高比
        private float _pw, _ph;//投影宽度和高度

        /// <summary>
        /// 初始化
        /// </summary>
        public void Initial(List<Vector3> vers, int width, int height)
        {
            UpdateViewPort(width, height);
            if (vers == null || vers.Count < 1)
            {
                vers = new List<Vector3>()
                {
                    new Vector3(-_width/2f,-_height/2f,-100f),
                    new Vector3(width/2f,height/2f,100f)
                };
            }
            _bx = new BoundingBox3(vers);
            _center = _bx.Center;
            _radius = _bx.Size.Length / 2f * 1.2f;
            UpdateMatrices();
        }

        /// <summary>
        /// 更新视口
        /// </summary>
        public void UpdateViewPort(int width, int height)
        {
            _width = width < 1 ? 1f : width;
            _height = height < 1 ? 1f : height;
            _aspect = _width / _height;
        }

        /// <summary>
        /// 更新缩放
        /// </summary>
        public void UpdateZoom(float scale)
        {
            this.Zoom *= scale;
        }

        /// <summary>
        /// 更新平移
        /// </summary>
        public void UpdateTranslation(float dx, float dy)
        {
            float xratio = _pw / _width;
            float yratio = _ph / _height;
            _translation.X += dx * xratio;
            _translation.Y -= dy * yratio;
        }

        /// <summary>
        /// 更新旋转
        /// </summary>
        public void UpdateRotation(float dx, float dy)
        {
            _rotation.X += dy / _radius;
            _rotation.Y += dx / _radius;
            _rotation.X = NormalizeAngle(_rotation.X);
            _rotation.Y = NormalizeAngle(_rotation.Y);
        }

        /// <summary>
        /// 更新模型矩阵
        /// </summary>
        public void UpdateModelMatrix()
        {
            _modelMatrix = Matrix4.CreateRotationX(_rotation.X) *
                Matrix4.CreateRotationY(_rotation.Y) *
                Matrix4.CreateTranslation(_translation * this.Zoom);
        }

        /// <summary>
        /// 更新视图矩阵
        /// </summary>
        public void UpdateViewMatrix()
        {
            var eye = new Vector3(_center.X, _center.Y, _center.Z + 2f * _radius);
            var target = _center;
            var up = Vector3.UnitY;
            _viewMatrix = Matrix4.LookAt(eye, target, up);
        }

        /// <summary>
        /// 更新投影矩阵
        /// </summary>
        public void UpdateProjectionMatrix()
        {
            _pw = _ph = _radius * 2f;
            if (_aspect > 1)
            {
                _pw *= _aspect;
            }
            else
            {
                _ph /= _aspect;
            }
            _projectionMatrix = Matrix4.CreateOrthographic(_pw * this.Zoom, _ph * this.Zoom, _radius, _radius * 3f);
        }

        /// <summary>
        /// 更新举证
        /// </summary>
        public void UpdateMatrices()
        {
            UpdateModelMatrix();
            UpdateViewMatrix();
            UpdateProjectionMatrix();
        }

        //标准化旋转弧度
        private static float NormalizeAngle(float angle)
        {
            // 取余操作
            angle %= 2 * MathF.PI;

            // 如果结果为负数，加上 2π 使其处于 [0, 2π) 区间
            if (angle < 0)
            {
                angle += 2 * MathF.PI;
            }

            return angle;
        }



    }
}