using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;
using EnvDTE;

public static class DTEHelper
{
    const uint S_OK = 0;

    [DllImport("ole32.dll")]
    public static extern uint GetRunningObjectTable(uint reserved, out IRunningObjectTable ROT);
    
    [DllImport("ole32.dll")]
    public static extern uint CreateBindCtx(uint reserved, out IBindCtx ctx);

    static IDictionary<string, object> GetRunningObjectTable()
    {                        
        IDictionary<string, object> rotTable = new Dictionary<string, object>();
        
        IRunningObjectTable runningObjectTable;            
        IEnumMoniker monikerEnumerator;
        IMoniker[] monikers = new IMoniker[1];

        GetRunningObjectTable(0, out runningObjectTable);
        runningObjectTable.EnumRunning(out monikerEnumerator);
        monikerEnumerator.Reset();

        IntPtr numberFetched = IntPtr.Zero;
        
        while (monikerEnumerator.Next(1, monikers, numberFetched) == 0)
        {
            IBindCtx ctx;
            CreateBindCtx(0, out ctx);

            string runningObjectName;
            monikers[0].GetDisplayName(ctx, null, out runningObjectName);
            Marshal.ReleaseComObject(ctx);

            object runningObjectValue;
            runningObjectTable.GetObject(monikers[0], out runningObjectValue);
            
            if (!rotTable.ContainsKey(runningObjectName))
                rotTable.Add(runningObjectName, runningObjectValue);
        }

        return rotTable;
    }

    public static IDictionary<string, _DTE> GetRunningVSIDETable()
    {            
        IDictionary<string, object> runningObjects = GetRunningObjectTable();
        IDictionary<string, _DTE> runningDTEObjects = new Dictionary<string, _DTE>();            

        foreach (string objectName in runningObjects.Keys)
        {
            if (!objectName.StartsWith("!VisualStudio.DTE"))
                continue;

            _DTE ide = runningObjects[objectName] as _DTE;
            if (ide == null)
                continue;
            
            runningDTEObjects.Add(objectName, ide);
        }

        return runningDTEObjects;
    }        
}