// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Copyright (c) 2007 Novell, Inc.
//
// Authors:
//	Geoff Norton (gnorton@novell.com)
//
//


using System;
using System.IO;
using System.Text;
using System.Drawing;
using System.Threading;
using System.Collections;
using System.Windows.Forms;
using System.Runtime.Serialization;
using System.Runtime.InteropServices;
using System.Runtime.Serialization.Formatters.Binary;

namespace System.Windows.Forms.CarbonInternal {
	internal delegate void DragTrackingDelegate (short message, IntPtr window, IntPtr data, IntPtr dragref);

	internal class Dnd {
		internal const uint kEventParamDragRef = 1685217639; 
		internal const uint typeDragRef = 1685217639;

		internal const uint typeMono = 1836019311;
		internal const uint typeMonoSerializedObject = 1836279154;

		private static DragDropEffects effects = DragDropEffects.None;
		private static DragTrackingDelegate DragTrackingHandler = new DragTrackingDelegate (TrackingCallback);

		static Dnd () {
			try {
				InstallTrackingHandler (DragTrackingHandler, IntPtr.Zero, IntPtr.Zero);
			} catch (EntryPointNotFoundException) {
				// it is deprecated in 10.6 and does not exist anymore.
			}
		}

		internal Dnd () {
		}

		internal static void TrackingCallback (short message, IntPtr window, IntPtr data, IntPtr dragref) {
			XplatUICarbon.GetInstance ().FlushQueue ();
		}
	
		internal static DragDropEffects DragActionsToEffects (UInt32 actions) {
			DragDropEffects effects = DragDropEffects.None;
			if ((actions & 1) != 0)
				effects |= DragDropEffects.Copy;
			if ((actions & (1 << 4)) != 0)
				effects |= DragDropEffects.Move;
			if ((actions & 0xFFFFFFFF) != 0)
				effects |= DragDropEffects.All;

			return effects;
		}

		internal static DataObject DragToDataObject (IntPtr dragref) {
			UInt32 items = 0;
			ArrayList flavorlist = new ArrayList ();

			CountDragItems (dragref, ref items);
			
			for (uint item_counter = 1; item_counter <= items; item_counter++) {
				IntPtr itemref = IntPtr.Zero;
				UInt32 flavors = 0;
				
				GetDragItemReferenceNumber (dragref, item_counter, ref itemref);
				CountDragItemFlavors (dragref, itemref, ref flavors);
				for (uint flavor_counter = 1; flavor_counter <= flavors; flavor_counter++) {
					FlavorHandler flavor = new FlavorHandler (dragref, itemref, flavor_counter);
					if (flavor.Supported)
						flavorlist.Add (flavor);
				}
			}

			if (flavorlist.Count > 0) {
				return ((FlavorHandler) flavorlist [0]).Convert (flavorlist);
			} 

			return new DataObject ();
		}

		internal static bool HandleEvent (IntPtr callref, IntPtr eventref, IntPtr handle, uint kind, ref MSG msg) {
			Control control;
			DataObject data;
			DragEventArgs drag_event;
			DragDropEffects allowed;
			QDPoint point = new QDPoint ();
			UInt32 actions = 0;
			IntPtr dragref = IntPtr.Zero;
			Hwnd hwnd = Hwnd.ObjectFromHandle (handle);

			if (hwnd == null || hwnd.Handle != handle)
				return false;

			GetEventParameter (eventref, kEventParamDragRef, typeDragRef, IntPtr.Zero, (uint) Marshal.SizeOf (typeof (IntPtr)), IntPtr.Zero, ref dragref);
			XplatUICarbon.GetGlobalMouse (ref point);
			GetDragAllowableActions (dragref, ref actions);
			control = Control.FromHandle (hwnd.Handle);
			allowed = DragActionsToEffects (actions);
			data = DragToDataObject (dragref);
			drag_event = new DragEventArgs (data, 0, point.x, point.y, allowed, DragDropEffects.None);
				
			switch (kind) {
				case ControlHandler.kEventControlDragEnter: {
					bool accept = control.AllowDrop;
					SetEventParameter (eventref, ControlHandler.kEventParamControlLikesDrag, ControlHandler.typeBoolean, (uint)Marshal.SizeOf (typeof (bool)), ref accept);

					control.DndEnter (drag_event);
					effects = drag_event.Effect;
					return false;
				}
				case ControlHandler.kEventControlDragWithin:
					control.DndOver (drag_event);
					effects = drag_event.Effect;
					break;
				case ControlHandler.kEventControlDragLeave:
					control.DndLeave (drag_event);
					break;
				case ControlHandler.kEventControlDragReceive:
					control.DndDrop (drag_event);
					break;
			}
			return true;
		}

		public void SetAllowDrop (Hwnd hwnd, bool allow) {
			if (hwnd.allow_drop == allow)
				return;

			hwnd.allow_drop = allow;
			SetControlDragTrackingEnabled (hwnd.whole_window, true);
			SetControlDragTrackingEnabled (hwnd.client_window, true);
		}

		public void SendDrop (IntPtr handle, IntPtr from, IntPtr time) {
		}

		public DragDropEffects StartDrag (IntPtr handle, object data, DragDropEffects allowed_effects) {
			IntPtr dragref = IntPtr.Zero;
			EventRecord eventrecord = new EventRecord ();

			effects = DragDropEffects.None;

			NewDrag (ref dragref);
			XplatUICarbon.GetGlobalMouse (ref eventrecord.mouse);
			StoreObjectInDrag (handle, dragref, data);

			TrackDrag (dragref, ref eventrecord, IntPtr.Zero);

			DisposeDrag (dragref);

			return effects;
		}

		public void StoreObjectInDrag (IntPtr handle, IntPtr dragref, object data) {
			IntPtr type = IntPtr.Zero;
			IntPtr dataptr = IntPtr.Zero;
			Int32 size = 0;

			if (data is string) {
				// implement me
				throw new NotSupportedException ("Implement me.");
			} else if (data is ISerializable) {
				MemoryStream stream = new MemoryStream ();
				BinaryFormatter bf = new BinaryFormatter ();

				bf.Serialize (stream, data);

				dataptr = Marshal.AllocHGlobal ((int) stream.Length);
				stream.Seek (0, 0);

				for (int i = 0; i < stream.Length; i++) {
					Marshal.WriteByte (dataptr, i, (byte) stream.ReadByte ());
				}
				
				type = (IntPtr) typeMonoSerializedObject;
				size = (int) stream.Length;
			} else {
				dataptr = (IntPtr) GCHandle.Alloc (data);

				type = (IntPtr) typeMono;
				size = Marshal.SizeOf (typeof (IntPtr));
			}

			AddDragItemFlavor (dragref, handle, type, ref dataptr, size, 1 << 0);
		}

		[DllImport ("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		static extern int InstallTrackingHandler (DragTrackingDelegate callback, IntPtr window, IntPtr data);

		[DllImport ("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		static extern int GetEventParameter (IntPtr eventref, uint name, uint type, IntPtr outtype, uint size, IntPtr outsize, ref IntPtr data);
		[DllImport ("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		static extern int SetEventParameter (IntPtr eventref, uint name, uint type, uint size, ref bool data);

		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int SetControlDragTrackingEnabled (IntPtr view, bool enabled);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int AddDragItemFlavor (IntPtr dragref, IntPtr itemref, IntPtr flavortype, ref IntPtr data, Int32 size, UInt32 flags);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int CountDragItems (IntPtr dragref, ref UInt32 count);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int CountDragItemFlavors (IntPtr dragref, IntPtr itemref, ref UInt32 count);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int GetDragItemReferenceNumber (IntPtr dragref, UInt32 index, ref IntPtr itemref);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int NewDrag (ref IntPtr dragref);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int TrackDrag (IntPtr dragref, ref EventRecord eventrecord, IntPtr region);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int DisposeDrag (IntPtr dragref);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int GetDragAllowableActions (IntPtr dragref, ref UInt32 actions);
	}

	internal struct EventRecord {
		internal UInt16 what;
		internal UInt32 message;
		internal UInt32 when;
		internal QDPoint mouse;
		internal UInt16 modifiers;
	}

	internal class FlavorHandler {
		internal IntPtr flavorref;
		internal IntPtr dragref;
		internal IntPtr itemref;
		internal Int32 size;
		internal UInt32 flags;
		internal byte [] data;
		internal string fourcc;

		internal FlavorHandler (IntPtr dragref, IntPtr itemref, uint counter) {
			GetFlavorType (dragref, itemref, counter, ref flavorref);
			GetFlavorFlags (dragref, itemref, flavorref, ref flags);
			byte [] fourcc_b = BitConverter.GetBytes ((Int32)flavorref);
			this.fourcc = String.Format ("{0}{1}{2}{3}", (char)fourcc_b [3], (char)fourcc_b [2], (char)fourcc_b [1], (char)fourcc_b [0]);
			this.dragref = dragref;
			this.itemref = itemref;

			this.GetData ();
		}

		internal void GetData () {
			GetFlavorDataSize (dragref, itemref, flavorref, ref size);
			data = new byte [size];
			GetFlavorData (dragref, itemref, flavorref, data, ref size, 0);
		}

		internal string DataString {
			get { return Encoding.Default.GetString (this.data); }
		}
		
		internal byte[] DataArray {
			get { return this.data; }
		}

		internal IntPtr DataPtr {
			get { return (IntPtr) BitConverter.ToInt32 (this.data, 0); }
		}

		internal bool Supported {
			get {
				switch (fourcc) {
					case "furl":
						return true;
					case "mono":
						return true;
					case "mser":
						return true;
				}
				return false;
			}
		}

		internal DataObject Convert (ArrayList flavorlist) {
			switch (fourcc) {
				case "furl":
					return ConvertToFileDrop (flavorlist);
				case "mono":
					return ConvertToObject (flavorlist);
				case "mser":
					return DeserializeObject (flavorlist);
			}

			return new DataObject ();
		}

		internal DataObject DeserializeObject (ArrayList flavorlist) {
			DataObject data = new DataObject ();
			MemoryStream stream = new MemoryStream (this.DataArray);
			BinaryFormatter bf = new BinaryFormatter ();

			if (stream.Length == 0)
				return data;

			stream.Seek (0, 0);
			data.SetData (bf.Deserialize (stream));

			return data;
		}

		internal DataObject ConvertToObject (ArrayList flavorlist) {
			DataObject data = new DataObject ();
			
			foreach (FlavorHandler flavor in flavorlist) {
				GCHandle handle = (GCHandle) flavor.DataPtr;

				data.SetData (handle.Target);
			}
			
			return data;
		}

		internal DataObject ConvertToFileDrop (ArrayList flavorlist) {
			DataObject data = new DataObject ();
			ArrayList uri_list = new ArrayList ();

			foreach (FlavorHandler flavor in flavorlist) {
				try {
					uri_list.Add (new Uri (flavor.DataString).LocalPath);			
				} catch { }
			}

			string [] l = (string []) uri_list.ToArray (typeof (string));
			if (l.Length < 1)
				return data;
			data.SetData (DataFormats.FileDrop, l);
			data.SetData ("FileName", l [0]);
			data.SetData ("FileNameW", l [0]);
			
			return data;
		}

		public override string ToString () {
			return fourcc;
		}
		
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int GetFlavorDataSize (IntPtr dragref, IntPtr itemref, IntPtr flavorref, ref Int32 size);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int GetFlavorData (IntPtr dragref, IntPtr itemref, IntPtr flavorref, [In, Out] byte[] data, ref Int32 size, UInt32 offset);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int GetFlavorFlags (IntPtr dragref, IntPtr itemref, IntPtr flavorref, ref UInt32 flags);
		[DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")]
		extern static int GetFlavorType (IntPtr dragref, IntPtr itemref, UInt32 index, ref IntPtr flavor);
	}
}