// Decompiled with JetBrains decompiler
// Type: SEGATools.Graphics.MRImageConverter
// Assembly: SEGATools, Version=1.0.3.0, Culture=neutral, PublicKeyToken=611be24fdeb07e08
// MVID: D631183F-57B1-40A1-B502-5364D288307A
// Assembly location: SEGATools.dll

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Text;

namespace SEGATools.Graphics
{
  public class MRImageConverter
  {
    private static readonly string MR_ID = "MR";
    private static readonly int MR_HEADER_OFFSET = 2;
    private static readonly int MR_COLOR_PALETTE_OFFSET = MRImageConverter.MR_HEADER_OFFSET + 28;
    private static readonly int MR_HEADER_MINIMUM_SIZE = 30;
    private static readonly int MR_COLOR_SIZE = 4;

    public static MRImage ToMRImage(byte[] buffer, int startIndex)
    {
      if (startIndex < 0 || buffer.Length - startIndex < MRImageConverter.MR_HEADER_MINIMUM_SIZE)
        throw new ArgumentOutOfRangeException();
      string str = Encoding.ASCII.GetString(buffer, startIndex, MRImageConverter.MR_ID.Length);
      if (!MRImageConverter.MR_ID.Equals(str))
        throw new MRImageIdentifierMissingException("Wrong MR file identifier");
      MRImageHeader structure1 = (MRImageHeader) Marshal.PtrToStructure(Marshal.UnsafeAddrOfPinnedArrayElement((Array) buffer, startIndex + MRImageConverter.MR_HEADER_OFFSET), typeof (MRImageHeader));
      if (structure1.NumberOfColors <= 0U || (long) (buffer.Length - startIndex - MRImageConverter.MR_COLOR_PALETTE_OFFSET) < (long) structure1.NumberOfColors * (long) MRImageConverter.MR_COLOR_SIZE)
        throw new MRImageDecompressionException("Color palette too big");
      Color[] colorArray = new Color[(int) structure1.NumberOfColors];
      for (int index1 = 0; index1 < colorArray.Length; ++index1)
      {
        int index2 = startIndex + MRImageConverter.MR_COLOR_PALETTE_OFFSET + index1 * MRImageConverter.MR_COLOR_SIZE;
        MRImageColor structure2 = (MRImageColor) Marshal.PtrToStructure(Marshal.UnsafeAddrOfPinnedArrayElement((Array) buffer, index2), typeof (MRImageColor));
        colorArray[index1] = Color.FromArgb((int) structure2.Alpha, (int) structure2.Red, (int) structure2.Green, (int) structure2.Blue);
      }
      int length = structure1.Size - structure1.Offset;
      int startIndex1 = startIndex + structure1.Offset;
      try
      {
        byte[] rawData = new byte[structure1.Size];
        Buffer.BlockCopy((Array) buffer, startIndex, (Array) rawData, 0, rawData.Length);
        byte[] pixels = MRImageConverter.DecompressPixelData(structure1, colorArray, buffer, startIndex1, length);
        return new MRImage(structure1, colorArray, pixels, startIndex, rawData);
      }
      catch (MRImageUnknownColorException ex)
      {
        throw new MRImageDecompressionException("Unable to decompress the image", (Exception) ex);
      }
      catch (Exception ex)
      {
        throw new MRImageDecompressionException("Unable to decompress the image", ex);
      }
    }

    private static byte[] DecompressPixelData(
      MRImageHeader mrHeader,
      Color[] palette,
      byte[] buffer,
      int startIndex,
      int length)
    {
      int length1 = palette.Length;
      int index1 = 0;
      byte[] buffer1 = new byte[mrHeader.Width * mrHeader.Height];
      for (int index2 = startIndex; index2 < startIndex + length; ++index2)
      {
        if (buffer[index2] < (byte) 128)
        {
          byte colorNumber = buffer[index2];
          index1 = MRImageConverter.decodePixels(buffer1, index1, colorNumber, length1, 1);
        }
        else if (buffer[index2] == (byte) 129)
        {
          int numberOfPixels = (int) buffer[index2 + 1];
          byte colorNumber = buffer[index2 + 2];
          index1 = MRImageConverter.decodePixels(buffer1, index1, colorNumber, length1, numberOfPixels);
          index2 += 2;
        }
        else if (buffer[index2] == (byte) 130 && buffer[index2 + 1] >= (byte) 128)
        {
          int numberOfPixels = (int) buffer[index2 + 1] - 128 + 256;
          byte colorNumber = buffer[index2 + 2];
          index1 = MRImageConverter.decodePixels(buffer1, index1, colorNumber, length1, numberOfPixels);
          index2 += 2;
        }
        else
        {
          int numberOfPixels = (int) buffer[index2] - 128;
          byte colorNumber = buffer[index2 + 1];
          index1 = MRImageConverter.decodePixels(buffer1, index1, colorNumber, length1, numberOfPixels);
          ++index2;
        }
      }
      return buffer1;
    }

    private static int decodePixels(
      byte[] buffer,
      int index,
      byte colorNumber,
      int numberOfColors,
      int numberOfPixels)
    {
      for (int index1 = 0; index1 < numberOfPixels && index < buffer.Length; ++index1)
      {
        if ((int) colorNumber >= numberOfColors)
          colorNumber = colorNumber == (byte) 154 ? (byte) 0 : throw MRImageUnknownColorException.anUnknownColor(colorNumber);
        buffer[index] = colorNumber;
        ++index;
      }
      return index;
    }
  }
}