using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Drawing;

// Created by Yousef El-Dardiry
//     yousef.dardiry.com

// Please let me know when you're using 
// this code in one of your projects

namespace Advanced_toolbar_buttons
{
    public class BHO : IObjectWithSite
    {
        private Win32.WndProc newWndProc;
        private Win32.WndProc newWndProcParent;
        private IntPtr oldWndProc = (IntPtr)null;
        private IntPtr oldWndProcParent = (IntPtr)null;
        private int imageProperty;
        
        // The command identifier of the button we're going to add.
        // We should make sure this one isn't being used already instead of just picking this number
        private uint BUTTON_CID = 1000;

        
        public BHO()
        {
            IntPtr hwnd = GetToolBarHWND();

            // Make sure the button hasn't been added yet
            if (Win32.SendMessage(hwnd, Win32.TB_COMMANDTOINDEX, BUTTON_CID, 0) == -1)
            {
                newWndProc = new Win32.WndProc(WindowProc);
                oldWndProc = Win32.SetWindowLong(hwnd, Win32.GWL_WNDPROC,
                       Marshal.GetFunctionPointerForDelegate(newWndProc));

                newWndProcParent = new Win32.WndProc(WindowProcParent);
                oldWndProcParent = Win32.SetWindowLong(GetToolBarParentHWND(), Win32.GWL_WNDPROC,
                       Marshal.GetFunctionPointerForDelegate(newWndProcParent));
            }
        }

        // Implement these functions yourself using a tool like 
        // Spy++ for the toolbar where you want to add your button
        private IntPtr GetToolBarParentHWND()
        {
            return IntPtr.Zero;
        }

        private IntPtr GetToolBarHWND()
        {
            return IntPtr.Zero;
        }

        
        private Win32.TBBUTTON getButton()
        {
            Win32.TBBUTTON button = new Win32.TBBUTTON();
            button.fsStyle = Win32.BTNS_WHOLEDROPDOWN | Win32.BTNS_SHOWTEXT;
            button.iString = (int)Marshal.StringToHGlobalAuto("Button");
            button.idCommand = (int)BUTTON_CID;
            button.iBitmap = imageProperty;
            return button;
        }

        private int WindowProc(
            IntPtr hwnd, uint msg, uint wParam, int lParam)
        {

            if (msg == Win32.TB_SETIMAGELIST)
            {
                // Obtain the Bitmap of the Icon we want to insert into the image list
                // This example works with resources, but you can do this however you like
                Bitmap bmp = Resource1.Normal.ToBitmap();

                // Add it into the Toolbar's image list
                int count = Win32.ImageList_GetImageCount((IntPtr)lParam);
                int res = Win32.ImageList_Add((IntPtr)lParam, bmp.GetHbitmap(), IntPtr.Zero);

                // Save this value for future use in the buttons iBitmap property
                imageProperty = Win32.MakeLong(res, (int)wParam);
            }
            else if (msg == Win32.TB_ADDBUTTONS)
            {
                // When TB_ADDBUTTONS gets called, we want to make sure our button gets added as well
                if (Win32.SendMessage(hwnd, Win32.TB_COMMANDTOINDEX, BUTTON_CID, 0) == -1)
                {
                    object[] buttons = MarshalEx.PtrToStructureArray((IntPtr)lParam, typeof(Win32.TBBUTTON), (int)wParam++);
                    object[] newbuttons = new object[wParam];

                    // Copy all buttons to newbuttons
                    for (int i = 0; i < wParam - 1; i++)
                    {
                        newbuttons[i] = buttons[i];
                    }

                    // Add our own button
                    newbuttons[wParam - 1] = getButton();

                    // Send newbuttons as lParam instead of the old buttons structure
                    lParam = (int)Marshal.AllocCoTaskMem((int)(wParam * Marshal.SizeOf(typeof(Win32.TBBUTTON))));
                    MarshalEx.StructureArrayToPtr((IntPtr)lParam, newbuttons);
                }
            }
            else if (msg == Win32.WM_NCDESTROY)
            {
                // Make sure we clean up before the window gets completely destroyed
                Win32.SetWindowLong(hwnd, Win32.GWL_WNDPROC,
                       oldWndProc);
            }
            return Win32.CallWindowProc(
                oldWndProc, hwnd, msg, wParam, lParam);
        }

        private int WindowProcParent(IntPtr hwnd, uint msg, uint wParam, int lParam)
        {
            if (msg == Win32.WM_COMMAND)
            {
                // Handle WM_COMMAND like you would do in a normal application
                // When one of your buttons gets clicked, you can notify other instances of your BHO of this 
                // by letting them handle a static event, and fire the event here.
            }
            else if (msg == Win32.WM_NOTIFY)
            {
                Win32.NMHDR nm = new Win32.NMHDR();
                Marshal.PtrToStructure((IntPtr)lParam, nm);

                if (nm.code == Win32.TBN_DROPDOWN)
                {
                    Win32.NMTOOLBAR nmtoolbar = (Win32.NMTOOLBAR)System.Runtime.InteropServices.Marshal.PtrToStructure((IntPtr)lParam, typeof(Win32.NMTOOLBAR));
                    if (nmtoolbar.iItem == BUTTON_CID)
                    {
                        // Show your menu using TrackPopupMenuEx here!
                    }
                }
                else if (nm.code == Win32.TBN_GETBUTTONINFO)
                {
                    // To make sure our button gets listed into the 'customize toolbar' form
                    // we simply add it as the first button requested

                    Win32.NMTOOLBAR toolbar = (Win32.NMTOOLBAR)Marshal.PtrToStructure((IntPtr)lParam, typeof(Win32.NMTOOLBAR));
                    String s = Marshal.PtrToStringAuto((IntPtr)toolbar.tbButton.iString);
                    if (toolbar.iItem == 1)
                    {
                        Win32.TBBUTTON button = getButton();
                        toolbar.tbButton = button;
                        toolbar.cchText = 6;
                        toolbar.pszText = (IntPtr)button.iString;
                        Marshal.StructureToPtr(toolbar, (IntPtr)lParam, true);
                        return 1;
                    }
                }
            }
            else if (msg == Win32.WM_NCDESTROY)
            {
                // Once again, make sure we clean up before the window gets completely destroyed
                Win32.SetWindowLong(hwnd, Win32.GWL_WNDPROC,
                       oldWndProcParent);
            }

            return Win32.CallWindowProc(
                oldWndProcParent, hwnd, msg, wParam, lParam);
        }
    }

    // We need these helper functions in the TB_ADDBUTTONS hook
    public class MarshalEx
    {
        public static object[] PtrToStructureArray(IntPtr pointer,
                               Type structureType, int len)
        {

            //----- Creates the array
            object[] array = new object[len];

            for (int i = 0; i < len; i++)
            {
                //----- Get the structure pointed from pointer parameter address
                array[i] = Marshal.PtrToStructure(pointer, structureType);

                //----- Add to the pointer parameter address the size of structure
                //----- After that, pointer parameter
                //----- points to the next structure in memory
                pointer = (IntPtr)(pointer.ToInt32() + Marshal.SizeOf(array[i]));
            }

            return array;

        }

        public static void StructureArrayToPtr(IntPtr pointer, object[] array)
        {
            for (int i = 0; i < array.Length; i++)
            {
                Marshal.StructureToPtr(array[i], pointer, true);
                pointer = (IntPtr)(pointer.ToInt32() + Marshal.SizeOf(array[i]));
            }
        }
    }

    public class Win32
    {
        public delegate int WndProc(IntPtr hwnd, uint msg, uint wParam, int lParam);

        #region Win32 function imports
        [DllImport("user32.dll")]
        public extern static int SendMessage(
            IntPtr hwnd, uint msg, uint wParam, uint lParam);

        [DllImport("user32.dll")]
        public extern static int SendMessage(
            IntPtr hwnd, uint msg, uint wParam, ref TBBUTTONINFO lParam);

        [DllImport("user32.dll")]
        public extern static IntPtr SetWindowLong(
            IntPtr hwnd, int nIndex, IntPtr dwNewLong);

        [DllImport("comctl32")]
        public extern static int ImageList_Add(
            IntPtr himl,
            IntPtr hbmImage,
            IntPtr hbmMask
            );

        [DllImport("comctl32")]
        public extern static int ImageList_GetImageCount(
            IntPtr himl);

        [DllImport("user32.dll")]
        public extern static int CallWindowProc(
            IntPtr lpPrevWndFunc, IntPtr hwnd, uint msg, uint wParam, int lParam);
        #endregion

        public static int MakeLong(int LoWord, int HiWord)
        {
            return (HiWord << 16) | (LoWord & 0xffff);
        }

        #region Win32 Constants
        public const int GWL_WNDPROC = -4;

        public const uint WM_NOTIFY = 0x4E;
        public const uint WM_USER = 0x0400;
        public const uint WM_NCDESTROY = 0x0082;
        public const uint WM_COMMAND = 0x0111;

        public const uint TB_COMMANDTOINDEX = WM_USER + 25;
        public const uint TB_SETBUTTONINFO = WM_USER + 64;
        public const uint TB_ADDBUTTONS = WM_USER + 68;
        public const uint TB_SETIMAGELIST = WM_USER + 48;

        public static uint SH = 700;
        public static uint ZERO = 0;
        public static uint TBN_FIRST = ZERO - SH;
        public static uint TBN_DROPDOWN = TBN_FIRST - 10;
        public static uint TBN_GETBUTTONINFO = TBN_FIRST - 20;

        public const byte BTNS_SHOWTEXT = 0x0040;
        public const byte BTNS_DROPDOWN = 0x0008;
        public const byte BTNS_WHOLEDROPDOWN = 0x0080;

        public const uint TBIF_IMAGE = 0x00000001;
        public const uint TBIF_TEXT = 0x00000002;
        public const uint TBIF_STATE = 0x00000004;
        public const uint TBIF_STYLE = 0x00000008;
        public const uint TBIF_LPARAM = 0x00000010;
        public const uint TBIF_COMMAND = 0x00000020;
        public const uint TBIF_SIZE = 0x00000040;
        public const uint TBIF_BYINDEX = 0x80000000;
        #endregion

        #region Win32 Struct definitions
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        public struct TBBUTTON
        {
            public int iBitmap;
            public int idCommand;
            public byte fsState;
            public byte fsStyle;
            public byte bReserved0;
            public byte bReserved1;
            public int dwData;
            public int iString;
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct TBBUTTONINFO
        {
            public int cbSize;
            public int dwMask;
            public int idCommand;
            public int iImage;
            public byte fsState;
            public byte fsStyle;
            public short cx;
            public IntPtr lParam;
            public IntPtr pszText;
            public int cchText;
        }

        [StructLayout(LayoutKind.Sequential)]
        public class NMHDR
        {
            private IntPtr hwndFrom;
            public uint idFrom;
            public uint code;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct NMTOOLBAR
        {
            public NMHDR hdr;
            public int iItem;
            public TBBUTTON tbButton;
            public int cchText;
            public IntPtr pszText;
            public RECT rcButton;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }
        #endregion
    }
}