//! \file       ImageSYG.cs
//! \date       Sun Jun 05 19:14:11 2016
//! \brief      West Vision image format.
//
// Copyright (C) 2016 by morkt
//
// 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.ComponentModel.Composition;
using System.IO;
using System.Windows.Media;
using GameRes.Utility;

namespace GameRes.Formats.WestVision
{
    internal class SygMetaData : ImageMetaData
    {
        public uint AlphaOffset;
    }

    [Export(typeof(ImageFormat))]
    public class SygFormat : ImageFormat
    {
        public override string         Tag { get { return "SYG"; } }
        public override string Description { get { return "West Vision image format"; } }
        public override uint     Signature { get { return 0x47595324; } } // '$SYG'

        public override ImageMetaData ReadMetaData (Stream stream)
        {
            var header = new byte[0x20];
            if (header.Length != stream.Read (header, 0, header.Length))
                return null;
            uint alpha_offset = LittleEndian.ToUInt32 (header, 0x1C);
            return new SygMetaData
            {
                Width  = LittleEndian.ToUInt32 (header, 0x10),
                Height = LittleEndian.ToUInt32 (header, 0x14),
                BPP = 0 == alpha_offset ? 24 : 32,
                AlphaOffset = alpha_offset,
            };
        }

        public override ImageData Read (Stream stream, ImageMetaData info)
        {
            var meta = (SygMetaData)info;
            int pixel_count = (int)meta.Width * (int)meta.Height;
            var pixels = new byte[pixel_count * 3];
            stream.Position = 0x20;
            if (pixels.Length != stream.Read (pixels, 0, pixels.Length))
                throw new EndOfStreamException ("Unexpected end of file");
            var format = PixelFormats.Bgr24;
            if (meta.AlphaOffset != 0)
            {
                var alpha = new byte[pixel_count];
                stream.Position = 0x20 + meta.AlphaOffset;
                if (alpha.Length == stream.Read (alpha, 0, alpha.Length))
                {
                    var output = new byte[pixel_count * 4];
                    int dst = 0;
                    int src = 0;
                    for (int i = 0; i < pixel_count; ++i)
                    {
                        output[dst++] = pixels[src++];
                        output[dst++] = pixels[src++];
                        output[dst++] = pixels[src++];
                        output[dst++] = alpha[i];
                    }
                    pixels = output;
                    format = PixelFormats.Bgra32;
                }
            }
            return ImageData.Create (info, format, null, pixels);
        }

        public override void Write (Stream file, ImageData image)
        {
            throw new System.NotImplementedException ("SygFormat.Write not implemented");
        }
    }
}