using OpenTK.GLControl;
using OpenTK.Graphics.OpenGL;
using OpenTK.Mathematics;
using System.Drawing.Imaging;

namespace Yw.WinFrmUI.Hydro
{
    /// <summary>
    /// 正交旋转2d辅助类
    /// </summary>
    internal class OrthoRotate2dHelper : IDisposable
    {
        /// <summary>
        /// 
        /// </summary>
        public OrthoRotate2dHelper() { }


        #region 静态资源

        //立方体尺寸
        private const int Size = 100;
        private const string UpText = "上";
        private const string DownText = "下";
        private const string LeftText = "左";
        private const string RightText = "右";
        private const string FrontText = "前";
        private const string BackText = "后";
        //颜色字典
        private readonly static Dictionary<string, Color> TextColor = new()
        {
            { UpText,ColorTranslator.FromHtml("#800080")},
            { DownText,ColorTranslator.FromHtml("#242424")},
            { LeftText,ColorTranslator.FromHtml("#87CEEB")},
            { RightText,ColorTranslator.FromHtml("#FF0000")},
            { FrontText,ColorTranslator.FromHtml("#00008B")},
            { BackText,ColorTranslator.FromHtml("#008000")},
        };

        #endregion

        #region 私有字段

        private GLControl _gl = null;//GL控件
        private OrthoCamera2d _camera = null;
        private Dictionary<string, int> _textures = null;//文本纹理
        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 (_gl == null)
                {
                    return false;
                }
                if (_camera == null)
                {
                    return false;
                }
                return true;
            }
        }

        #endregion

        /// <summary>
        /// 初始化
        /// </summary>
        public void Initial(GLControl gl)
        {
            _gl = gl;
            _camera = new OrthoCamera2d();
            _camera.Initial(GetVertices(), gl.Width, gl.Height);
        }

        #region 辅助方法

        //初始化GL状态
        private void InitialGLState()
        {
            GL.ClearColor(Color.LightBlue);
            GL.Enable(EnableCap.DepthTest);
            GL.Enable(EnableCap.Texture2D);
            GL.Enable(EnableCap.Blend);
            GL.BlendFunc(BlendingFactor.SrcAlpha, BlendingFactor.OneMinusSrcAlpha);

            // 生成六个面的文字纹理
            CreateTextures();
            Resize();
        }

        //绘制立方体
        private void DrawCube()
        {
            GL.Begin(PrimitiveType.Quads);

            // 上 (Z+ 方向)
            GL.Color3(TextColor[UpText]);
            var vers = GetVertices(UpText);
            vers.ForEach(x => GL.Vertex3(x));


            // 下 (Z- 方向)
            GL.Color3(TextColor[DownText]);
            vers = GetVertices(DownText);
            vers.ForEach(x => GL.Vertex3(x));

            // 左 (X- 方向)
            GL.Color3(TextColor[LeftText]);
            vers = GetVertices(LeftText);
            vers.ForEach(x => GL.Vertex3(x));

            // 右 (X+ 方向)
            GL.Color3(TextColor[RightText]);
            vers = GetVertices(RightText);
            vers.ForEach(x => GL.Vertex3(x));

            // 后 (Y+ 方向)
            GL.Color3(TextColor[BackText]);
            vers = GetVertices(BackText);
            vers.ForEach(x => GL.Vertex3(x));

            // 前 (Y- 方向)
            GL.Color3(TextColor[FrontText]);
            vers = GetVertices(FrontText);
            vers.ForEach(x => GL.Vertex3(x));

            GL.End();
        }

        //获取坐标
        private List<Vector3> GetVertices(string text)
        {
            float half = Size / 2f;
            List<Vector3> vertices = null;
            switch (text)
            {
                case UpText:
                    vertices = new List<Vector3>()
                    {
                         new Vector3(-half, -half, half),
                         new Vector3(half, -half, half),
                         new Vector3(half, half, half),
                         new Vector3(-half, half, half)
                    };
                    break;
                case DownText:
                    vertices = new List<Vector3>()
                    {
                         new Vector3(-half, -half, -half),
                         new Vector3(-half, half, -half),
                         new Vector3(half, half, -half),
                         new Vector3(half, -half, -half)
                    };
                    break;
                case LeftText:
                    vertices = new List<Vector3>()
                    {
                         new Vector3(-half, -half, -half),
                         new Vector3(-half, -half, half),
                         new Vector3(-half, half, half),
                         new Vector3(-half, half, -half)
                    };
                    break;
                case RightText:
                    vertices = new List<Vector3>()
                    {
                         new Vector3(half, -half, half),
                         new Vector3(half, -half, -half),
                         new Vector3(half, half, -half),
                         new Vector3(half, half, half)
                    };
                    break;
                case BackText:
                    vertices = new List<Vector3>()
                    {
                         new Vector3(-half, half, half),
                         new Vector3(half, half, half),
                         new Vector3(half, half, -half),
                         new Vector3(-half, half, -half)
                     };
                    break;
                case FrontText:
                    vertices = new List<Vector3>()
                    {
                         new Vector3(-half, -half, -half),
                         new Vector3(half, -half, -half),
                         new Vector3(half, -half, half),
                         new Vector3(-half, -half, half)
                    };
                    break;
                default: break;
            }
            return vertices;
        }

        //获取坐标
        private List<Vector3> GetVertices()
        {
            var texts = new List<string>() { UpText, DownText, LeftText, RightText, FrontText, BackText };
            return texts.SelectMany(x => GetVertices(x)).ToList();
        }

        //创建纹理
        private void CreateTexture(string text)
        {
            if (_textures == null)
            {
                _textures = new Dictionary<string, int>();
            }
            if (_textures.ContainsKey(text))
            {
                return;
            }

            // 创建位图并绘制文字
            using (var bmp = new Bitmap(Size, Size))
            using (var gfx = Graphics.FromImage(bmp))
            {
                var bgColor = TextColor[text];
                gfx.Clear(bgColor);
                var font = new Font("宋体", 32, FontStyle.Bold);
                var format = new StringFormat
                {
                    Alignment = StringAlignment.Center,
                    LineAlignment = StringAlignment.Center
                };

                gfx.DrawString(text, font, new SolidBrush(Color.White),
                    new RectangleF(0, 0, Size, Size), format);
                //反转y轴（图片坐标与GL屏幕坐标y轴正好是相反的）
                bmp.RotateFlip(RotateFlipType.RotateNoneFlipY);

                // 转换位图为OpenGL纹理
                var data = bmp.LockBits(
                    new Rectangle(0, 0, bmp.Width, bmp.Height),
                    ImageLockMode.ReadOnly,
                    System.Drawing.Imaging.PixelFormat.Format32bppArgb);

                int texId = GL.GenTexture();
                GL.BindTexture(TextureTarget.Texture2D, texId);
                GL.TexImage2D(TextureTarget.Texture2D, 0,
                    PixelInternalFormat.Rgba,
                    data.Width, data.Height, 0,
                    OpenTK.Graphics.OpenGL.PixelFormat.Bgra,
                    PixelType.UnsignedByte, data.Scan0);

                // 设置纹理参数
                GL.TexParameter(TextureTarget.Texture2D,
                    TextureParameterName.TextureMinFilter,
                    (int)TextureMinFilter.Linear);
                GL.TexParameter(TextureTarget.Texture2D,
                    TextureParameterName.TextureMagFilter,
                    (int)TextureMagFilter.Linear);

                bmp.UnlockBits(data);

                _textures.Add(text, texId);
            }
        }

        //创建纹理s
        private void CreateTextures()
        {
            var texts = new List<string>() { UpText, DownText, LeftText, RightText, FrontText, BackText };
            texts.ForEach(x => CreateTexture(x));
        }

        //绘制纹理
        private void DrawTexture(string text)
        {
            if (_textures == null || _textures.Count < 1)
            {
                return;
            }
            var tetId = _textures[text];
            var vers = GetVertices(text);

            GL.BindTexture(TextureTarget.Texture2D, tetId);
            GL.Begin(PrimitiveType.Quads);

            GL.TexCoord2(0, 0); GL.Vertex3(vers[0]);
            GL.TexCoord2(1, 0); GL.Vertex3(vers[1]);
            GL.TexCoord2(1, 1); GL.Vertex3(vers[2]);
            GL.TexCoord2(0, 1); GL.Vertex3(vers[3]);

            // 修正后的纹理坐标（翻转Y方向）
            //GL.TexCoord2(0, 1); GL.Vertex3(vers[0]); // 左上→左下
            //GL.TexCoord2(1, 1); GL.Vertex3(vers[1]); // 右上→右下
            //GL.TexCoord2(1, 0); GL.Vertex3(vers[2]); // 右下→右上
            //GL.TexCoord2(0, 0); GL.Vertex3(vers[3]); // 左下→左上

            GL.End();
        }

        //绘制纹理s
        private void DrawTextures()
        {
            var texts = new List<string>() { UpText, DownText, LeftText, RightText, FrontText, BackText };
            texts.ForEach(x => DrawTexture(x));
        }


        #endregion

        #region 交互处理

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

        /// <summary>
        /// 调整大小
        /// </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);
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
            //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);

            //DrawCube();
            DrawTextures();

            var error = GL.GetError();

            _gl.SwapBuffers();
        }

        /// <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();
            }
            else if (_isTranslation)
            {
                _camera.UpdateTranslation(dx, dy);
                _camera.UpdateMatrices();
            }
            _lastMos = e.Location;
            _gl.Invalidate();
        }

        /// <summary>
        /// 鼠标滚动
        /// </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>
        /// 鼠标点击
        /// </summary>
        public void MouseClick(MouseEventArgs e)
        {

        }

        /// <summary>
        /// 鼠标双击
        /// </summary>
        public void MouseDoubleClick(MouseEventArgs e)
        {

        }

        #endregion

        /// <summary>
        /// 释放
        /// </summary>
        public void Dispose()
        {
            if (_textures != null && _textures.Count > 0)
            {
                GL.DeleteTextures(_textures.Count, _textures.Values.ToArray());
            }
        }

    }
}