using Microsoft.Win32;

using System;
using System.Runtime.InteropServices;

namespace WPFluent.Controls
{
    public sealed class VistaFolderBrowserDialog
    {
        private IFileOpenDialog CreateNativeDialog() { return (IFileOpenDialog)new FileOpenDialog(); }

        private Fos GetDialogOptions()
        {
            Fos options = Fos.Pickfolders;
            if(Multiselect)
            {
                options |= Fos.Allowmultiselect;
            }

            if(!AllowNonStoragePlaces)
            {
                options |= Fos.Forcefilesystem;
            }

            return options;
        }

        private void GetPathAndElementName(IShellItem item, out string path, out string elementName)
        {
            item.GetDisplayName(Sigdn.Parentrelativeforaddressbar, out elementName);
            try
            {
                item.GetDisplayName(Sigdn.Filesyspath, out path);
            } catch(ArgumentException ex) when (ex.HResult == -2147024809)
            {
                path = null;
            }
        }

        private void SetDialogResults(IFileOpenDialog dialog)
        {
            IShellItem item;
            if(!Multiselect)
            {
                dialog.GetResult(out item);
                string path, value;
                GetPathAndElementName(item, out path, out value);
                SelectedPath = path;
                SelectedPaths = new[] { path };
                SelectedElementName = value;
                SelectedElementNames = new[] { value };
            }
            else
            {
                IShellItemArray items;
                dialog.GetResults(out items);

                uint count;
                items.GetCount(out count);

                SelectedPaths = new string[count];
                SelectedElementNames = new string[count];

                for(uint i = 0; i < count; ++i)
                {
                    items.GetItemAt(i, out item);
                    string path, value;
                    GetPathAndElementName(item, out path, out value);
                    SelectedPaths[i] = path;
                    SelectedElementNames[i] = value;
                }

                SelectedPath = null;
                SelectedElementName = null;
            }
        }

        private void SetInitialFolder(IFileOpenDialog dialog)
        {
            IShellItem item;
            if(!string.IsNullOrEmpty(SelectedPath))
            {
                IntPtr idl;
                uint atts = 0;
                if(NativeMethods.SHILCreateFromPath(SelectedPath, out idl, ref atts) == 0 &&
                    NativeMethods.SHCreateShellItem(IntPtr.Zero, IntPtr.Zero, idl, out item) == 0)
                {
                    dialog.SetFolder(item);
                }
            }
        }

        private void SetOptions(IFileOpenDialog dialog) { dialog.SetOptions(GetDialogOptions()); }

        public bool ShowDialog() { return ShowDialog(IntPtr.Zero); }

        public bool ShowDialog(Window owner)
        { return ShowDialog(owner == null ? IntPtr.Zero : new WindowInteropHelper(owner).Handle); }

        public bool ShowDialog(IWin32Window owner) { return ShowDialog(owner == null ? IntPtr.Zero : owner.Handle); }

        public bool ShowDialog(IntPtr owner)
        {
            if(Environment.OSVersion.Version.Major < 6)
            {
                throw new InvalidOperationException("对话框需要至少在Visia系统以上才能使用");
            }

            IFileOpenDialog dialog = CreateNativeDialog();
            try
            {
                SetInitialFolder(dialog);
                SetOptions(dialog);

                if(dialog.Show(owner) != 0)
                {
                    return false;
                }

                SetDialogResults(dialog);

                return true;
            } finally
            {
                Marshal.ReleaseComObject(dialog);
            }
        }

        public bool AllowNonStoragePlaces { get; set; }

        public bool Multiselect { get; set; }

        public string SelectedElementName { get; private set; }

        public string[] SelectedElementNames { get; private set; }

        public string SelectedPath { get; set; }

        public string[] SelectedPaths { get; private set; }

        [ComImport]
        [Guid("DC1C5A9C-E88A-4dde-A5A1-60F82A20AEF7")]
        private class FileOpenDialog
        {
        }

        private class NativeMethods
        {
            [DllImport("user32.dll")]
            public static extern IntPtr GetActiveWindow();

            [DllImport("shell32.dll")]
            public static extern int SHCreateShellItem(
                IntPtr pidlParent,
                IntPtr psfParent,
                IntPtr pidl,
                out IShellItem ppsi);

            [DllImport("shell32.dll")]
            public static extern int SHILCreateFromPath(
                [MarshalAs(UnmanagedType.LPWStr)] string pszPath,
                out IntPtr ppIdl,
                ref uint rgflnOut);
        }

        [Flags]
        private enum Fos
        {
            Allnonstorageitems = 0x80,

            Allowmultiselect = 0x200,

            Createprompt = 0x2000,

            Defaultnominimode = 0x20000000,

            Dontaddtorecent = 0x2000000,

            Filemustexist = 0x1000,

            Forcefilesystem = 0x40,

            Forceshowhidden = 0x10000000,

            Hidemruplaces = 0x20000,

            Hidepinnedplaces = 0x40000,

            Nochangedir = 8,

            Nodereferencelinks = 0x100000,

            Noreadonlyreturn = 0x8000,

            Notestfilecreate = 0x10000,

            Novalidate = 0x100,

            Overwriteprompt = 2,

            Pathmustexist = 0x800,

            Pickfolders = 0x20,

            Shareaware = 0x4000,

            Strictfiletypes = 4
        }

        [ComImport]
        [Guid("d57c7288-d4ad-4768-be02-9d969532d960")]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        [CoClass(typeof(FileOpenDialog))]
        private interface IFileOpenDialog
        {
            [PreserveSig]
            int Show([In] IntPtr parent);

            void SetFileTypes([In] uint cFileTypes, [In][MarshalAs(UnmanagedType.Struct)] ref IntPtr rgFilterSpec);

            void SetFileTypeIndex([In] uint iFileType);

            void GetFileTypeIndex(out uint piFileType);

            void Advise([In][MarshalAs(UnmanagedType.Interface)] IntPtr pfde, out uint pdwCookie);

            void Unadvise([In] uint dwCookie);

            void SetOptions([In] Fos fos);

            void GetOptions(out Fos pfos);

            void SetDefaultFolder([In][MarshalAs(UnmanagedType.Interface)] IShellItem psi);

            void SetFolder([In][MarshalAs(UnmanagedType.Interface)] IShellItem psi);

            void GetFolder([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            void GetCurrentSelection([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            void SetFileName([In][MarshalAs(UnmanagedType.LPWStr)] string pszName);

            void GetFileName([MarshalAs(UnmanagedType.LPWStr)] out string pszName);

            void SetTitle([In][MarshalAs(UnmanagedType.LPWStr)] string pszTitle);

            void SetOkButtonLabel([In][MarshalAs(UnmanagedType.LPWStr)] string pszText);

            void SetFileNameLabel([In][MarshalAs(UnmanagedType.LPWStr)] string pszLabel);

            void GetResult([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            void AddPlace([In][MarshalAs(UnmanagedType.Interface)] IShellItem psi, FileDialogCustomPlace fdcp);

            void SetDefaultExtension([In][MarshalAs(UnmanagedType.LPWStr)] string pszDefaultExtension);

            void Close([MarshalAs(UnmanagedType.Error)] int hr);

            void SetClientGuid([In] ref Guid guid);

            void ClearClientData();

            void SetFilter([MarshalAs(UnmanagedType.Interface)] IntPtr pFilter);

            void GetResults([MarshalAs(UnmanagedType.Interface)] out IShellItemArray ppenum);

            void GetSelectedItems([MarshalAs(UnmanagedType.Interface)] out IShellItemArray ppsai);
        }

        [ComImport]
        [Guid("43826D1E-E718-42EE-BC55-A1E261C37BFE")]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        private interface IShellItem
        {
            void BindToHandler(
                [In][MarshalAs(UnmanagedType.Interface)] IntPtr pbc,
                [In] ref Guid bhid,
                [In] ref Guid riid,
                out IntPtr ppv);

            void GetParent([MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            void GetDisplayName([In] Sigdn sigdnName, [MarshalAs(UnmanagedType.LPWStr)] out string ppszName);

            void GetAttributes([In] uint sfgaoMask, out uint psfgaoAttribs);

            void Compare([In][MarshalAs(UnmanagedType.Interface)] IShellItem psi, [In] uint hint, out int piOrder);
        }

        [ComImport]
        [Guid("B63EA76D-1F85-456F-A19C-48159EFA858B")]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        private interface IShellItemArray
        {
            void BindToHandler(
                [In][MarshalAs(UnmanagedType.Interface)] IntPtr pbc,
                [In] ref Guid rbhid,
                [In] ref Guid riid,
                out IntPtr ppvOut);

            void GetPropertyStore([In] int flags, [In] ref Guid riid, out IntPtr ppv);

            void GetPropertyDescriptionList(
                [In][MarshalAs(UnmanagedType.Struct)] ref IntPtr keyType,
                [In] ref Guid riid,
                out IntPtr ppv);

            void GetAttributes(
                [In][MarshalAs(UnmanagedType.I4)] IntPtr dwAttribFlags,
                [In] uint sfgaoMask,
                out uint psfgaoAttribs);

            void GetCount(out uint pdwNumItems);

            void GetItemAt([In] uint dwIndex, [MarshalAs(UnmanagedType.Interface)] out IShellItem ppsi);

            void EnumItems([MarshalAs(UnmanagedType.Interface)] out IntPtr ppenumShellItems);
        }

        private enum Sigdn : uint
        {
            Desktopabsoluteediting = 0x8004c000,

            Desktopabsoluteparsing = 0x80028000,

            Filesyspath = 0x80058000,

            Normaldisplay = 0,

            Parentrelative = 0x80080001,

            Parentrelativeediting = 0x80031001,

            Parentrelativeforaddressbar = 0x8007c001,

            Parentrelativeparsing = 0x80018001,

            Url = 0x80068000
        }
    }
}