using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;

namespace RichCreator.Utility
{
    /// <summary>
    /// 鼠标全局钩子
    /// </summary>
    public class MouseHook:IDisposable
    {

        public MouseHook(MouseEvent mouseEvent)
        {
            this.OnMouseActivity = mouseEvent;
        }

        public enum MouseButton:Int32
        {
            None                =0,
            MouseMove           = 0x200,
            LeftButtonDown      = 0x201,
            RightButtonDown     = 0x204,
            middleButtonDown   = 0x207,
            LeftButtonUp        = 0x202,
            RightButtonUp       = 0x205,
            MiddleButtonUp     = 0x208,
            LeftButtonClick = 0x203,
            RightButtonClick = 0x206,
            MiddleButtonClick = 0x209,
        }

        /// <summary>
        /// 鼠标事件
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <param name="clickCount"></param>
        /// <param name="button"></param>
        public delegate void MouseEvent(Int32 x,Int32 y,Int32 clickCount,MouseButton button);
        

        /// <summary>
        /// 点
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        private class POINT
        {
            public int x;
            public int y;
        }

        /// <summary>
        /// 钩子结构体
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        private class MouseHookStruct
        {
            public POINT pt;
            public int hWnd;
            public int wHitTestCode;
            public int dwExtraInfo;
        }


        // 钩子回调函数
        private delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);


        private const int WH_MOUSE_LL = 14; // mouse hook constant
        // 装置钩子的函数
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        private static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);

        // 卸下钩子的函数
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        private static extern bool UnhookWindowsHookEx(int idHook);

        // 下一个钩挂的函数
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        private static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);

        private event MouseEvent OnMouseActivity;  // 全局的鼠标事件
        private HookProc mouseHookProcedure;// 声明鼠标钩子事件类型
        private static int hMouseHook = 0; // 鼠标钩子句柄
        private bool isFinalize=false;//是否已主动释放
        

        /// <summary>
        /// 启动全局钩子
        /// </summary>
        public void Start()
        {
            // 安装鼠标钩子
            if (hMouseHook == 0)
            {
                mouseHookProcedure = new HookProc(MouseHookProc);
                Module module = System.Reflection.Assembly.GetExecutingAssembly().GetModules()[0];
                // 生成一个HookProc的实例.
                hMouseHook = SetWindowsHookEx(WH_MOUSE_LL, mouseHookProcedure, Marshal.GetHINSTANCE(module), 0);

                //假设装置失败停止钩子
                if (hMouseHook == 0)
                {
                    Close();
                    throw new Exception("SetWindowsHookEx failed.");
                }
            }
        }


        
        /// <summary>
        /// 停止全局钩子
        /// </summary>
        public void Close()
        {
            if (isFinalize)
            {
                return;
            }
            bool retMouse = true;

            if (hMouseHook != 0)
            {
                retMouse = UnhookWindowsHookEx(hMouseHook);
                hMouseHook = 0;
            }

            // 假设卸下钩子失败
            if (!(retMouse))
            {
                throw new Exception("UnhookWindowsHookEx failed.");
            }
            isFinalize = true;
            GC.SuppressFinalize(this);
        }

        /// <summary>
        /// 鼠标钩子回调函数
        /// </summary>
        private int MouseHookProc(int nCode, Int32 wParam, IntPtr lParam)
        {
            // 假设正常执行而且用户要监听鼠标的消息
            if ((nCode >= 0) && (OnMouseActivity != null))
            {
                MouseButton button = MouseButton.None;
                Enum.TryParse<MouseButton>(wParam.ToString(), out button);

                int clickCount = 0;
                switch (button)
                {
                    case MouseButton.LeftButtonDown:
                        clickCount = 1;
                        break;
                    case MouseButton.LeftButtonUp:
                        clickCount = 1;
                        break;
                    case MouseButton.LeftButtonClick:
                        clickCount = 2;
                        break;
                    case MouseButton.RightButtonDown:
                        clickCount = 1;
                        break;
                    case MouseButton.RightButtonUp:
                        clickCount = 1;
                        break;
                    case MouseButton.RightButtonClick:
                        clickCount = 2;
                        break;
                }

                // 从回调函数中得到鼠标的信息
                MouseHookStruct MyMouseHookStruct = (MouseHookStruct)Marshal.PtrToStructure(lParam, typeof(MouseHookStruct));
                
                //MouseEvent e = new MouseEventArgs(button, clickCount, MyMouseHookStruct.pt.x, MyMouseHookStruct.pt.y, 0);

                //// 假设想要限制鼠标在屏幕中的移动区域能够在此处设置
                //// 后期须要考虑实际的x、y的容差
                //if (!Screen.PrimaryScreen.Bounds.Contains(e.X, e.Y))
                //{
                //    //return 1;
                //}

                OnMouseActivity(MyMouseHookStruct.pt.x, MyMouseHookStruct.pt.y,clickCount, button);
            }

            // 启动下一次钩子
            return CallNextHookEx(hMouseHook, nCode, wParam, lParam);
        }

        public void Dispose()
        {
            Close();
        }
    }
}