using ShellExtensions.Interop.Common;
using System;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;

namespace ShellExtensions.Interop
{
    internal static class HandlerNativeMethods
    {
        internal static readonly Guid IThumbnailProviderGuid = new Guid("e357fccd-a995-4576-b01f-234630154e96");

        internal static readonly Guid IInitializeWithFileGuid = new Guid("b7d14566-0509-4cce-a71f-0a554233bd9b");
        internal static readonly Guid IInitializeWithStreamGuid = new Guid("b824b49d-22ac-4161-ac8a-9916e8fa3f7f");
        //internal static readonly Guid IInitializeWithItemGuid = new Guid("7f73be3f-fb79-493c-a6c7-7ee14e245841");

        internal static readonly Guid IMarshalGuid = new Guid("00000003-0000-0000-C000-000000000046");
    }

    #region Interfaces

    /// <summary>
    /// ComVisible interface for native IThumbnailProvider
    /// </summary>
    [ComImport]
    [Guid("e357fccd-a995-4576-b01f-234630154e96")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface IThumbnailProvider
    {
        /// <summary>
        /// Gets a pointer to a bitmap to display as a thumbnail
        /// </summary>
        /// <param name="squareLength"></param>
        /// <param name="bitmapHandle"></param>
        /// <param name="bitmapType"></param>
        void GetThumbnail(uint squareLength, [Out] out IntPtr bitmapHandle, [Out] out uint bitmapType);
    }

    /// <summary>
    /// Provides means by which to initialize with a file.
    /// </summary>
    [ComImport]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    [Guid("b7d14566-0509-4cce-a71f-0a554233bd9b")]
    interface IInitializeWithFile
    {
        /// <summary>
        /// Initializes with a file.
        /// </summary>
        /// <param name="filePath"></param>
        /// <param name="fileMode"></param>
        void Initialize([MarshalAs(UnmanagedType.LPWStr)] string filePath, AccessModes fileMode);
    }

    /// <summary>
    /// Provides means by which to initialize with a stream.
    /// </summary>
    [ComImport]
    [Guid("b824b49d-22ac-4161-ac8a-9916e8fa3f7f")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface IInitializeWithStream
    {
        /// <summary>
        /// Initializes with a stream.
        /// </summary>
        /// <param name="stream"></param>
        /// <param name="fileMode"></param>
        void Initialize(IStream stream, AccessModes fileMode);
    }

    #endregion

    // <summary>
    /// Thumbnail Alpha Types
    /// </summary>
    public enum ThumbnailAlphaType
    {
        /// <summary>
        /// Let the system decide.
        /// </summary>
        Unknown = 0,

        /// <summary>
        /// No transparency
        /// </summary>
        NoAlphaChannel = 1,

        /// <summary>
        /// Has transparency
        /// </summary>
        HasAlphaChannel = 2,
    }
}