//
// Copyright (C) 2008 Aaron Bockover, abockover@novell.com
// Copyright (C) 2008 Jordi Mas i Hernandez, jmas@softcatala.org
//
// 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.
//

using System;
using System.Runtime.InteropServices;

using Cairo;

namespace Mistelix.Widgets
{
	public class DataImageSurface : ImageSurface, IDisposable
	{
		delegate void cairo_destroy_func_t (IntPtr userdata);
		static int user_data_key = 0;
		static cairo_destroy_func_t destroy_func;
		protected IntPtr data;
		static protected bool is_le = BitConverter.IsLittleEndian;
		       
		static void DestroyPixelData (IntPtr data)
		{
			Marshal.FreeHGlobal (data);
		}

		static DataImageSurface ()
		{
		    	destroy_func = new cairo_destroy_func_t (DestroyPixelData);
		}

		static public IntPtr Allocate (byte [] pixels)
		{
			IntPtr ptr = Marshal.AllocHGlobal (pixels.Length);		
			Marshal.Copy (pixels, 0, ptr, pixels.Length);
			return ptr;
		}

		public DataImageSurface (IntPtr data, Cairo.Format format, int width, int height, int stride) : base (data, format, width, height, width * 4)
		{
			this.data = data;
			SetDestroyFunc ();
		}

		public byte[] Get24bitsPixBuf ()
		{
			return FromCairo32ToPixBuf (Data, Width, Height, 3);
		}

		// Converts a pixel data array from Cairo 32-bits to GDK 24/32 bits
		static public byte[] FromCairo32ToPixBuf (byte[] cairo_pixels, int width, int height, int channels)
		{
			int pos_cairo = 0;
			int pos_gdk = 0;
			byte [] pixels;

			pixels = new byte [height * width * channels];

			for (int h = 0; h < height; h++) 
			{
				for (int i = 0; i < width; i++)
				{
					if (is_le) {
						pixels[pos_gdk + 2] = cairo_pixels[pos_cairo + 0];
					   	pixels[pos_gdk + 1] = cairo_pixels[pos_cairo + 1];
					   	pixels[pos_gdk + 0] = cairo_pixels[pos_cairo + 2];

						if (channels == 4)
							pixels[pos_gdk + 3] = cairo_pixels[pos_cairo + 3];
						
						
					} else {
					   	pixels[pos_gdk + 0] = cairo_pixels[pos_cairo + 1];
					   	pixels[pos_gdk + 1] = cairo_pixels[pos_cairo + 2];
					   	pixels[pos_gdk + 2] = cairo_pixels[pos_cairo + 3];

						if (channels == 4)
							pixels[pos_gdk + 3] = cairo_pixels[pos_cairo + 0];
					}

					pos_gdk += channels;
					pos_cairo += 4;
				}
			}
			return pixels;
		}

		[DllImport ("libcairo.so.2")]
		static extern Cairo.Status cairo_surface_set_user_data (IntPtr surface, ref int key, IntPtr userdata, cairo_destroy_func_t destroy);

		void SetDestroyFunc ()
		{
			try {
				Cairo.Status status = cairo_surface_set_user_data (Handle, ref user_data_key, data, destroy_func);
				if (status != Cairo.Status.Success) {
				    throw new ApplicationException (String.Format (
					"cairo_surface_set_user_data returned {0}", status));
				}
			} catch (Exception e) {
				Console.Error.WriteLine (e);	
			}
		}
	}
}