using System.IO;

namespace MyNes.Core;

[BoardInfo("HK-SF3", 91, true, true)]
internal class Mapper091 : Board
{
	private bool irq_enabled;

	private byte irq_counter;

	private int old_irq_counter;

	private byte irq_reload;

	private bool irq_clear;

	internal override void HardReset()
	{
		base.HardReset();
		Switch16KPRG(PRG_ROM_16KB_Mask, PRGArea.AreaC000);
	}

	internal override void WriteSRM(ref ushort address, ref byte data)
	{
		switch (address & 0x7003)
		{
		case 24576:
			Switch02KCHR(data, CHRArea.Area0000);
			break;
		case 24577:
			Switch02KCHR(data, CHRArea.Area0800);
			break;
		case 24578:
			Switch02KCHR(data, CHRArea.Area1000);
			break;
		case 24579:
			Switch02KCHR(data, CHRArea.Area1800);
			break;
		case 28672:
			Switch08KPRG(data & 0xF, PRGArea.Area8000);
			break;
		case 28673:
			Switch08KPRG(data & 0xF, PRGArea.AreaA000);
			break;
		case 28674:
			irq_enabled = false;
			NesEmu.IRQFlags &= -9;
			break;
		case 28675:
			irq_enabled = true;
			irq_reload = 7;
			irq_counter = 0;
			break;
		}
	}

	internal override void OnPPUA12RaisingEdge()
	{
		old_irq_counter = irq_counter;
		if (irq_counter == 0 || irq_clear)
		{
			irq_counter = irq_reload;
		}
		else
		{
			irq_counter--;
		}
		if ((old_irq_counter != 0 || irq_clear) && irq_counter == 0 && irq_enabled)
		{
			NesEmu.IRQFlags |= 8;
		}
		irq_clear = false;
	}

	internal override void WriteStateData(ref BinaryWriter stream)
	{
		base.WriteStateData(ref stream);
		stream.Write(irq_enabled);
		stream.Write(irq_counter);
		stream.Write(old_irq_counter);
		stream.Write(irq_reload);
		stream.Write(irq_clear);
	}

	internal override void ReadStateData(ref BinaryReader stream)
	{
		base.ReadStateData(ref stream);
		irq_enabled = stream.ReadBoolean();
		irq_counter = stream.ReadByte();
		old_irq_counter = stream.ReadInt32();
		irq_reload = stream.ReadByte();
		irq_clear = stream.ReadBoolean();
	}
}