using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using EnvDTE;
using System.Runtime.InteropServices;

namespace Reformatter
{
    class Program
    {
        [STAThread]
        static void Main(string[] args)
        {
            if (args.Length != 1)
            {
                System.Console.WriteLine("Syntax: one argument: a file which will be run through Visual Studio's auto-formatter.");
            }
            else
            {
                var file = args[0];
                if (!Path.IsPathRooted(file))
                {
                    file = Directory.GetCurrentDirectory() + "\\" + file;
                }

                FormatFile(file);
            }
        }

        static void FormatFile(string file)
        {
            EnvDTE.Solution soln = System.Activator.CreateInstance(
                Type.GetTypeFromProgID("VisualStudio.Solution.12.0")) as EnvDTE.Solution;

            // Registering the message filter lets us retry commands that the threading model
            // can't handle at the moment because windows is stupid and hasn't built up their
            // com interface stuff to handle multiple requests simultaneously
            MessageFilter.Register();
            {
                var window = soln.DTE.ItemOperations.OpenFile(file);

                TextSelection selection = window.Selection as TextSelection;
                selection.SelectAll();
                selection.SmartFormat();

                soln.DTE.ActiveDocument.Save();
            }
            MessageFilter.Revoke();
        }

        public class MessageFilter : IOleMessageFilter
        {
            //
            // Class containing the IOleMessageFilter
            // thread error-handling functions.

            // Start the filter.
            public static void Register()
            {
                IOleMessageFilter newFilter = new MessageFilter();
                IOleMessageFilter oldFilter = null;
                
                var result = CoRegisterMessageFilter(newFilter, out oldFilter);
                if (result != 0)
                {
                    System.Console.WriteLine("Error 0x{0:X}", result);
                }
            }

            // Done with the filter, close it.
            public static void Revoke()
            {
                IOleMessageFilter oldFilter = null;
                var result = CoRegisterMessageFilter(null, out oldFilter);
                if (result != 0)
                {
                    System.Console.WriteLine("Error 0x{0:X}", result);
                }
            }

            //
            // IOleMessageFilter functions.
            // Handle incoming thread requests.
            int IOleMessageFilter.HandleInComingCall(int dwCallType,
              System.IntPtr hTaskCaller, int dwTickCount, System.IntPtr
              lpInterfaceInfo)
            {
                //Return the flag SERVERCALL_ISHANDLED.
                return 0;
            }

            // Thread call was rejected, so try again.
            int IOleMessageFilter.RetryRejectedCall(System.IntPtr
              hTaskCallee, int dwTickCount, int dwRejectType)
            {
                if (dwRejectType == 2)
                // flag = SERVERCALL_RETRYLATER.
                {
                    // Retry the thread call immediately if return >=0 & 
                    // <100.
                    return 99;
                }
                // Too busy; cancel call.
                return -1;
            }

            int IOleMessageFilter.MessagePending(System.IntPtr hTaskCallee,
              int dwTickCount, int dwPendingType)
            {
                //Return the flag PENDINGMSG_WAITDEFPROCESS.
                return 2;
            }

            // Implement the IOleMessageFilter interface.
            [DllImport("Ole32.dll")]
            private static extern int
              CoRegisterMessageFilter(IOleMessageFilter newFilter, out 
          IOleMessageFilter oldFilter);
        }

        [ComImport(), Guid("00000016-0000-0000-C000-000000000046"),
        InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
        interface IOleMessageFilter
        {
            [PreserveSig]
            int HandleInComingCall(
                int dwCallType,
                IntPtr hTaskCaller,
                int dwTickCount,
                IntPtr lpInterfaceInfo);

            [PreserveSig]
            int RetryRejectedCall(
                IntPtr hTaskCallee,
                int dwTickCount,
                int dwRejectType);

            [PreserveSig]
            int MessagePending(
                IntPtr hTaskCallee,
                int dwTickCount,
                int dwPendingType);
        }
    }
}