class LevelCompatibility play
{
	private static void Apply()
	{
		string checksum = level.GetChecksum();

		if (   checksum ~== "AB24AE6E2CB13CBDD04600A4D37F9189"   // doom2.wad map02
			|| checksum ~== "1EC0AF1E3985650F0C9000319C599D0C")  // doom2bfg.wad map02
		{
			// Missing textures
			TextureID stone4 = TexMan.CheckForTexture("STONE4", TexMan.Type_Wall);
			SetWallTextureID(327, Line.front, Side.bottom, stone4);
			SetWallTextureID(328, Line.front, Side.bottom, stone4);
			SetWallTextureID(338, Line.front, Side.bottom, stone4);
			SetWallTextureID(339, Line.front, Side.bottom, stone4);
		}
		else if (checksum ~== "66C46385EB1A23D60839D1532522076B")  // doom2.wad map08
		{
			// Missing texture
			SetWallTexture(101, Line.back, Side.top, "BRICK7");
		}
	}

	private static void SetWallTexture(int line, int side, int texpart, String texture)
	{
		SetWallTextureID(line, side, texpart, TexMan.CheckForTexture(texture, TexMan.Type_Wall));
	}

	private static void SetWallTextureID(int line, int side, int texpart, TextureID texture)
	{
		level.Lines[line].sidedef[side].SetTexture(texpart, texture);
	}
}