using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;

namespace VSoft.Prams
{
    /// <summary>
    /// 鼠标全局钩子
    /// </summary>
    public class MouseHook
    {
        private const int WM_MOUSEMOVE = 0x200;
        private const int WM_LBUTTONDOWN = 0x201;
        private const int WM_RBUTTONDOWN = 0x204;
        private const int WM_MBUTTONDOWN = 0x207;
        private const int WM_XBUTTONDOWN = 0x20B;
        private const int WM_LBUTTONUP = 0x202;
        private const int WM_RBUTTONUP = 0x205;
        private const int WM_MBUTTONUP = 0x208;
        private const int WM_XBUTTON1 = 0x20B;
        private const int WM_XBUTTON2 = 0x20C;
        private const int WM_LBUTTONDBLCLK = 0x203;
        private const int WM_RBUTTONDBLCLK = 0x206;
        private const int WM_MBUTTONDBLCLK = 0x209;

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

        /// <summary>
        /// 钩子结构体
        /// </summary>
        [StructLayout(LayoutKind.Explicit)]
        public class MouseHookStruct
        {
            /// <summary>
            ///     Specifies a Point structure that contains the X- and Y-coordinates of the cursor, in screen coordinates.
            /// </summary>
            [FieldOffset(0x00)] public System.Drawing.Point Point;

            /// <summary>
            ///     Specifies information associated with the message.
            /// </summary>
            /// <remarks>
            ///     The possible values are:
            ///     <list type="bullet">
            ///         <item>
            ///             <description>0 - No Information</description>
            ///         </item>
            ///         <item>
            ///             <description>1 - X-Button1 Click</description>
            ///         </item>
            ///         <item>
            ///             <description>2 - X-Button2 Click</description>
            ///         </item>
            ///         <item>
            ///             <description>120 - Mouse Scroll Away from User</description>
            ///         </item>
            ///         <item>
            ///             <description>-120 - Mouse Scroll Toward User</description>
            ///         </item>
            ///     </list>
            /// </remarks>
            [FieldOffset(0x0A)] public short MouseData;

            /// <summary>
            ///     Returns a Timestamp associated with the input, in System Ticks.
            /// </summary>
            [FieldOffset(0x10)] public int Timestamp;
        }

        public 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)]
        public 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)]
        public static extern bool UnhookWindowsHookEx(int idHook);

        // 下一个钩挂的函数
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);
        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr GetModuleHandle(string lpModuleName);

        // 全局的鼠标事件
        public event MouseEventHandler OnMouseActivity;

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

        // 声明鼠标钩子事件类型
        private HookProc _mouseHookProcedure;
        private static int _hMouseHook = 0; // 鼠标钩子句柄

        /// <summary>
        /// 构造函数
        /// </summary>
        public MouseHook()
        {

        }

        /// <summary>
        /// 析构函数
        /// </summary>
        ~MouseHook()
        {
            Stop();
        }
        /// <summary>
        /// 启动全局钩子
        /// </summary>
        public void Start()
        {
            // 安装鼠标钩子
            if (_hMouseHook == 0)
            {
                // 生成一个HookProc的实例.
                _mouseHookProcedure = new HookProc(MouseHookProc);

                _hMouseHook = SetWindowsHookEx(WH_MOUSE_LL, _mouseHookProcedure, Process.GetCurrentProcess().MainModule.BaseAddress, 0);

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

        /// <summary>
        /// 停止全局钩子
        /// </summary>
        public void Stop()
        {
            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.");
        }

        /// <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))
            {
                MouseButtons button = MouseButtons.None;
                int clickCount = 0;
                // 从回调函数中得到鼠标的信息
                MouseHookStruct MyMouseHookStruct = (MouseHookStruct)Marshal.PtrToStructure(lParam, typeof(MouseHookStruct));
                switch (wParam)
                {
                    case WM_LBUTTONDOWN:
                        button = MouseButtons.Left;
                        clickCount = 1;
                        break;
                    case WM_LBUTTONUP:
                        button = MouseButtons.Left;
                        clickCount = 1;
                        break;
                    case WM_LBUTTONDBLCLK:
                        button = MouseButtons.Left;
                        clickCount = 2;
                        break;
                    case WM_RBUTTONDOWN:
                        button = MouseButtons.Right;
                        clickCount = 1;
                        break;
                    case WM_RBUTTONUP:
                        button = MouseButtons.Right;
                        clickCount = 1;
                        break;
                    case WM_RBUTTONDBLCLK:
                        button = MouseButtons.Right;
                        clickCount = 2;
                        break;
                    case WM_MBUTTONDOWN:
                        button = MouseButtons.Middle;
                        clickCount = 1;
                        break;
                    //case WM_MBUTTONUP:
                    //    button = MouseButtons.Middle;
                    //    clickCount = 1;
                    //    break;
                    case WM_XBUTTONDOWN:
                        button = MyMouseHookStruct.MouseData == 1
                        ? MouseButtons.XButton1
                        : MouseButtons.XButton2;
                        clickCount = 1;
                        break;
                    default:
                        break;
                }
                MouseEventArgs e = new MouseEventArgs(button, clickCount, MyMouseHookStruct.Point.X, MyMouseHookStruct.Point.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(this, e);
            }

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