using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Xml;
using System.Xml.Serialization;

namespace ModernWpf.SampleApp.Helpers
{
    // RECT structure required by WINDOWPLACEMENT structure
    [Serializable]
    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        public int Left;
        public int Top;
        public int Right;
        public int Bottom;

        public RECT(int left, int top, int right, int bottom)
        {
            Left = left;
            Top = top;
            Right = right;
            Bottom = bottom;
        }
    }

    // POINT structure required by WINDOWPLACEMENT structure
    [Serializable]
    [StructLayout(LayoutKind.Sequential)]
    public struct POINT
    {
        public int X;
        public int Y;

        public POINT(int x, int y)
        {
            X = x;
            Y = y;
        }
    }

    // WINDOWPLACEMENT stores the position, size, and state of a window
    [Serializable]
    [StructLayout(LayoutKind.Sequential)]
    public struct WINDOWPLACEMENT
    {
        public int length;
        public int flags;
        public int showCmd;
        public POINT minPosition;
        public POINT maxPosition;
        public RECT normalPosition;
    }

    public static class WindowPlacement
    {
        private static Encoding encoding = new UTF8Encoding();
        private static XmlSerializer serializer = new XmlSerializer(typeof(WINDOWPLACEMENT));

        [DllImport("user32.dll")]
        private static extern bool SetWindowPlacement(IntPtr hWnd, [In] ref WINDOWPLACEMENT lpwndpl);

        [DllImport("user32.dll")]
        private static extern bool GetWindowPlacement(IntPtr hWnd, out WINDOWPLACEMENT lpwndpl);

        private const int SW_SHOWNORMAL = 1;
        private const int SW_SHOWMINIMIZED = 2;

        public static void SetPlacement(IntPtr windowHandle, string placementXml)
        {
            if (string.IsNullOrEmpty(placementXml))
            {
                return;
            }

            WINDOWPLACEMENT placement;
            byte[] xmlBytes = encoding.GetBytes(placementXml);

            try
            {
                using (MemoryStream memoryStream = new MemoryStream(xmlBytes))
                {
                    placement = (WINDOWPLACEMENT)serializer.Deserialize(memoryStream);
                }

                placement.length = Marshal.SizeOf(typeof(WINDOWPLACEMENT));
                placement.flags = 0;
                placement.showCmd = placement.showCmd == SW_SHOWMINIMIZED ? SW_SHOWNORMAL : placement.showCmd;
                SetWindowPlacement(windowHandle, ref placement);
            }
            catch (InvalidOperationException)
            {
                // Parsing placement XML failed. Fail silently.
            }
        }

        public static string GetPlacement(IntPtr windowHandle)
        {
            WINDOWPLACEMENT placement = new WINDOWPLACEMENT();
            GetWindowPlacement(windowHandle, out placement);

            using (MemoryStream memoryStream = new MemoryStream())
            {
                using (XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream, Encoding.UTF8))
                {
                    serializer.Serialize(xmlTextWriter, placement);
                    byte[] xmlBytes = memoryStream.ToArray();
                    return encoding.GetString(xmlBytes);
                }
            }
        }
    }
}