using OpenTK.GLControl;
using OpenTK.Graphics.OpenGL;
using OpenTK.Mathematics;

namespace Yw.WinFrmUI.Hydro
{
    /// <summary>
    /// 正交2d视图辅助类
    /// </summary>
    internal class OrthoViewer2dHelper
    {

        /// <summary>
        /// 辅助类
        /// </summary>
        public OrthoViewer2dHelper() { }

        #region 公共事件

        /// <summary>
        /// 旋转改变事件
        /// </summary>
        public event Action<Vector3> RotationChangedEvent;

        #endregion

        #region 私有字段

        private GLControl _gl = null;//gl控件
        private NetworkL3d _nw = null;//管网模型
        private Vector3CacheHelper _veccache = null;//位置缓存
        private OrthoCamera2d _camera = null;//相机
        private Point _lastMos;//最近的鼠标位置
        private bool _isTranslation, _isRotation;

        #endregion

        #region 公共属性

        /// <summary>
        /// 是否初始化
        /// </summary>
        public bool Initialized
        {
            get
            {
                if (_nw == null)
                {
                    return false;
                }
                if (_gl == null)
                {
                    return false;
                }
                if (_camera == null)
                {
                    return false;
                }
                return true;
            }
        }

        #endregion

        /// <summary>
        /// 初始化
        /// </summary>
        public void Initial(GLControl gl, NetworkL3d nw)
        {
            _gl = gl;
            _nw = nw;
            _veccache = new Vector3CacheHelper(nw);
            _camera = new OrthoCamera2d();
            _camera.Initial(_veccache.GetAll(), gl.Width, gl.Height);
        }


        #region 辅助方法

        //初始化GL状态
        private void InitialGLState()
        {
            GL.ClearColor(Color.Transparent); // 背景颜色
            GL.Enable(EnableCap.DepthTest);//深度测试
            GL.DepthMask(true); // 允许写入深度缓冲区
            GL.Enable(EnableCap.PointSmooth);//启用点平滑
            GL.Enable(EnableCap.LineSmooth);//启用线平滑
            GL.Enable(EnableCap.Multisample);// 启用反锯齿
            GL.ShadeModel(ShadingModel.Smooth);

            // 设置混合模式以支持反锯齿
            GL.Enable(EnableCap.Blend);
            GL.BlendFunc(BlendingFactor.SrcAlpha, BlendingFactor.OneMinusSrcAlpha);
            Resize();
        }

        #endregion

        #region 交互处理

        /// <summary>
        /// 加载
        /// </summary>
        public void Load()
        {
            if (!Initialized)
            {
                return;
            }
            _gl.MakeCurrent();
            InitialGLState();
        }

        /// <summary>
        /// 大小改变
        /// </summary>
        public void Resize()
        {
            if (!Initialized)
            {
                return;
            }
            _gl.MakeCurrent();
            _camera.UpdateViewPort(_gl.Width, _gl.Height);
            GL.Viewport(0, 0, _gl.Width, _gl.Height);
            _camera.UpdateMatrices();
            _gl.Invalidate();
        }

        /// <summary>
        /// 绘制
        /// </summary>
        public void Render()
        {
            if (!Initialized)
            {
                return;
            }
            _gl.MakeCurrent();
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit | ClearBufferMask.StencilBufferBit);
            //投影矩阵
            GL.MatrixMode(MatrixMode.Projection);
            var projectionMatrix = _camera.ProjectionMatrix;
            GL.LoadMatrix(ref projectionMatrix);

            //视图矩阵
            GL.MatrixMode(MatrixMode.Modelview);
            var viewMatrix = _camera.ViewMatrix;
            GL.LoadMatrix(ref viewMatrix);

            var modelMatrix = _camera.ModelMatrix;
            GL.MultMatrix(ref modelMatrix);

            _nw.Draw2d(_camera.Zoom);

            _gl.SwapBuffers();
        }

        /// <summary>
        /// 鼠标滚轮
        /// </summary>
        public void MouseWheel(MouseEventArgs e)
        {
            if (!Initialized)
            {
                return;
            }
            var scale = e.Delta > 0 ? 0.9f : 1.1f;
            _camera.UpdateZoom(scale);
            _camera.UpdateMatrices();
            _gl.Invalidate();
        }

        /// <summary>
        /// 鼠标按下
        /// </summary>
        public void MouseDown(MouseEventArgs e)
        {
            if (!Initialized)
            {
                return;
            }
            _lastMos = e.Location;
            if (e.Button == MouseButtons.Right)
            {
                _isTranslation = true;
                _gl.Cursor = Cursors.SizeAll; // 修改光标样式
            }
            else if (e.Button == MouseButtons.Left)
            {
                _isRotation = true;
                _gl.Cursor = Cursors.SizeAll; // 修改光标样式
            }
        }

        /// <summary>
        /// 鼠标弹起
        /// </summary>
        public void MouseUp(MouseEventArgs e)
        {
            if (!Initialized)
            {
                return;
            }
            _lastMos = e.Location;
            if (e.Button == MouseButtons.Right)
            {
                _isTranslation = false;
                _gl.Cursor = Cursors.Default;
            }
            else if (e.Button == MouseButtons.Left)
            {
                _isRotation = false;
                _gl.Cursor = Cursors.Default;
            }

            _gl.Invalidate();
        }

        /// <summary>
        /// 鼠标移动
        /// </summary>
        public void MouseMove(MouseEventArgs e)
        {
            if (!Initialized)
            {
                return;
            }
            float dx = e.X - _lastMos.X;
            float dy = e.Y - _lastMos.Y;

            if (_isRotation)
            {
                _camera.UpdateRotation(dx, dy);
                _camera.UpdateMatrices();
                this.RotationChangedEvent?.Invoke(_camera.Rotation);
            }
            else if (_isTranslation)
            {
                _camera.UpdateTranslation(dx, dy);
                _camera.UpdateMatrices();
            }

            var ray = OrthoTransformHelper.CreateRay(e.X, e.Y, _camera.ModelMatrix, _camera.ViewMatrix, _camera.ProjectionMatrix, _gl.Width, _gl.Height);
            if (ray != null)
            {
                _nw.Hover2d(ray, _camera.Zoom, _veccache);
            }

            _lastMos = e.Location;
            _gl.Invalidate();

        }

        /// <summary>
        /// 鼠标点击
        /// </summary>
        public void MouseClick(MouseEventArgs e)
        {
            if (!Initialized)
            {
                return;
            }
            var ray = OrthoTransformHelper.CreateRay(e.X, e.Y, _camera.ModelMatrix, _camera.ViewMatrix, _camera.ProjectionMatrix, _gl.Width, _gl.Height);
            if (ray != null)
            {
                _nw.Select2d(ray, _camera.Zoom, _veccache);
            }
            _gl.Invalidate();
        }

        /// <summary>
        /// 鼠标双击
        /// </summary>
        public void MouseDoubleClick(MouseEventArgs e)
        {
            var depth = OrthoTransformHelper.GetScreenPointDepth(e.X, e.Y, _gl.Height);
            var world = OrthoTransformHelper.ScreenToWorld(e.X, e.Y, depth, _camera.ModelMatrix, _camera.ViewMatrix, _camera.ProjectionMatrix, _gl.Width, _gl.Height);
            MessageBox.Show($"x:{world.X},y:{world.Y},z:{world.Z}");
        }

        #endregion









    }
}