namespace ConsoleApplication1.SP
{
    public sealed class OamWriteCycle : ICycle
    {
        private readonly Oam oam;
        private readonly Registers registers;

        public OamWriteCycle(Oam oam, Registers registers)
        {
            this.oam = oam;
            this.registers = registers;
        }

        public void Execute()
        {
            oam.Sprite[oam.SpriteIndex] = oam.Latch;

            if ((oam.SpriteIndex & 3) == 0)
            {
                int compare = (registers.V - oam.Latch) & 0x1ff;
                if (compare >= 8)
                {
                    oam.MemoryIndex = (oam.MemoryIndex + 4) & 0xff;

                    if (oam.SpriteCount < 8)
                    {
                        return;
                    }
                }
            }

            oam.MemoryIndex = (oam.MemoryIndex + 1) & 0xff;
            oam.SpriteIndex = (oam.SpriteIndex + 1) & 0x1f;
        }
    }
}