using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace Tango.RemoteDesktop.Utils
{
    /// <summary>
    /// Represents a static cursor helper.
    /// </summary>
    public static class CursorUtils
    {
        #region INTERNALS

        internal static class User32
        {
            public const Int32 CURSOR_SHOWING = 0x00000001;

            [StructLayout(LayoutKind.Sequential)]
            public struct ICONINFO
            {
                public bool fIcon;
                public Int32 xHotspot;
                public Int32 yHotspot;
                public IntPtr hbmMask;
                public IntPtr hbmColor;
            }

            [StructLayout(LayoutKind.Sequential)]
            public struct POINT
            {
                public Int32 x;
                public Int32 y;
            }

            [StructLayout(LayoutKind.Sequential)]
            public struct CURSORINFO
            {
                public Int32 cbSize;
                public Int32 flags;
                public IntPtr hCursor;
                public POINT ptScreenPos;
            }

            [DllImport("user32.dll")]
            public static extern bool GetCursorInfo(out CURSORINFO pci);

            [DllImport("user32.dll")]
            public static extern IntPtr CopyIcon(IntPtr hIcon);

            [DllImport("user32.dll", SetLastError = true)]
            public static extern bool DestroyIcon(IntPtr hIcon);

            [DllImport("user32.dll", SetLastError = true)]
            public static extern bool DrawIconEx(IntPtr hdc, int xLeft, int yTop, IntPtr hIcon, int cxWidth, int cyHeight, int istepIfAniCur, IntPtr hbrFlickerFreeDraw, int diFlags);

            [DllImport("user32.dll")]
            public static extern bool DrawIcon(IntPtr hdc, int x, int y, IntPtr hIcon);

            [DllImport("user32.dll")]
            public static extern bool GetIconInfo(IntPtr hIcon, out ICONINFO piconinfo);
        }

        #endregion

        #region Internal Classes

        [StructLayout(LayoutKind.Sequential)]
        struct CURSORINFO
        {
            public Int32 cbSize;
            public Int32 flags;
            public IntPtr hCursor;
            public POINTAPI ptScreenPos;
        }

        [StructLayout(LayoutKind.Sequential)]
        struct POINTAPI
        {
            public int x;
            public int y;
        }

        [DllImport("user32.dll")]
        static extern bool GetCursorInfo(out CURSORINFO pci);

        [DllImport("user32.dll")]
        static extern bool DrawIcon(IntPtr hDC, int X, int Y, IntPtr hIcon);

        const Int32 CURSOR_SHOWING = 0x00000001;

        internal struct SIZE
        {
            public int cx;
            public int cy;
        }

        internal class GDIStuff
        {
            #region Class Variables
            public const int SRCCOPY = 13369376;
            #endregion


            #region Class Functions
            [DllImport("gdi32.dll", EntryPoint = "CreateDC")]
            public static extern IntPtr CreateDC(IntPtr lpszDriver, string lpszDevice, IntPtr lpszOutput, IntPtr lpInitData);

            [DllImport("gdi32.dll", EntryPoint = "DeleteDC")]
            public static extern IntPtr DeleteDC(IntPtr hDc);

            [DllImport("gdi32.dll", EntryPoint = "DeleteObject")]
            public static extern IntPtr DeleteObject(IntPtr hDc);

            [DllImport("gdi32.dll", EntryPoint = "BitBlt")]
            public static extern bool BitBlt(IntPtr hdcDest, int xDest,
                                             int yDest, int wDest,
                                             int hDest, IntPtr hdcSource,
                                             int xSrc, int ySrc, int RasterOp);

            [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleBitmap")]
            public static extern IntPtr CreateCompatibleBitmap
                                        (IntPtr hdc, int nWidth, int nHeight);

            [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleDC")]
            public static extern IntPtr CreateCompatibleDC(IntPtr hdc);

            [DllImport("gdi32.dll", EntryPoint = "SelectObject")]
            public static extern IntPtr SelectObject(IntPtr hdc, IntPtr bmp);
            #endregion
        }

        internal class Win32Stuff
        {

            #region Class Variables

            public const int SM_CXSCREEN = 0;
            public const int SM_CYSCREEN = 1;

            public const Int32 CURSOR_SHOWING = 0x00000001;

            [StructLayout(LayoutKind.Sequential)]
            public struct ICONINFO
            {
                public bool fIcon;         // Specifies whether this structure defines an icon or a cursor. A value of TRUE specifies 
                public Int32 xHotspot;     // Specifies the x-coordinate of a cursor's hot spot. If this structure defines an icon, the hot 
                public Int32 yHotspot;     // Specifies the y-coordinate of the cursor's hot spot. If this structure defines an icon, the hot 
                public IntPtr hbmMask;     // (HBITMAP) Specifies the icon bitmask bitmap. If this structure defines a black and white icon, 
                public IntPtr hbmColor;    // (HBITMAP) Handle to the icon color bitmap. This member can be optional if this 
            }
            [StructLayout(LayoutKind.Sequential)]
            public struct POINT
            {
                public Int32 x;
                public Int32 y;
            }

            [StructLayout(LayoutKind.Sequential)]
            public struct CURSORINFO
            {
                public Int32 cbSize;        // Specifies the size, in bytes, of the structure. 
                public Int32 flags;         // Specifies the cursor state. This parameter can be one of the following values:
                public IntPtr hCursor;          // Handle to the cursor. 
                public POINT ptScreenPos;       // A POINT structure that receives the screen coordinates of the cursor. 
            }

            #endregion


            #region Class Functions

            [DllImport("user32.dll", EntryPoint = "GetDesktopWindow")]
            public static extern IntPtr GetDesktopWindow();

            [DllImport("user32.dll", EntryPoint = "GetDC")]
            public static extern IntPtr GetDC(IntPtr ptr);

            [DllImport("user32.dll", EntryPoint = "GetSystemMetrics")]
            public static extern int GetSystemMetrics(int abc);

            [DllImport("user32.dll", EntryPoint = "GetWindowDC")]
            public static extern IntPtr GetWindowDC(Int32 ptr);

            [DllImport("user32.dll", EntryPoint = "ReleaseDC")]
            public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc);


            [DllImport("user32.dll", EntryPoint = "GetCursorInfo")]
            public static extern bool GetCursorInfo(out CURSORINFO pci);

            [DllImport("user32.dll", EntryPoint = "CopyIcon")]
            public static extern IntPtr CopyIcon(IntPtr hIcon);

            [DllImport("user32.dll", SetLastError = true)]
            static extern bool DestroyIcon(IntPtr hIcon);

            [DllImport("user32.dll", EntryPoint = "GetIconInfo")]
            public static extern bool GetIconInfo(IntPtr hIcon, out ICONINFO piconinfo);


            #endregion
        }

        #endregion

        /// <summary>
        /// Applies the current user cursor icon at the specified position on the specified bitmap.
        /// </summary>
        /// <param name="graphics">The drawing graphics object.</param>
        /// <param name="bitmap">The bitmap.</param>
        /// <param name="left">The left cursor position.</param>
        /// <param name="top">The top cursor position.</param>
        [DebuggerHidden]
        [DebuggerStepThrough]
        public static void ApplyCursor(System.Drawing.Graphics graphics, System.Drawing.Bitmap bitmap, int left, int top)
        {
            try
            {
                CURSORINFO pci;
                pci.cbSize = Marshal.SizeOf(typeof(CURSORINFO));

                if (GetCursorInfo(out pci))
                {
                    if (pci.flags == CURSOR_SHOWING)
                    {
                        //var iconPointer = User32.CopyIcon(pci.hCursor);
                        //User32.ICONINFO iconInfo;
                        //User32.GetIconInfo(iconPointer, out iconInfo);

                        var hdc = graphics.GetHdc();
                        User32.DrawIconEx(hdc, pci.ptScreenPos.x - left, pci.ptScreenPos.y - top, pci.hCursor, 0, 0, 0, IntPtr.Zero, 0x0003);

                        //User32.DestroyIcon(iconPointer);
                        GDIStuff.DeleteObject(pci.hCursor);
                    }
                }
                graphics.ReleaseHdc();
            }
            catch { }
        }
    }
}