namespace MyNes.Core;

[BoardInfo("Irem H-3001", 65)]
internal class Mapper065 : Board
{
	private bool irq_enable;

	private int irq_reload;

	private int irq_counter;

	internal override void HardReset()
	{
		base.HardReset();
		Switch08KPRG(0, PRGArea.Area8000);
		Switch08KPRG(1, PRGArea.AreaA000);
		Switch08KPRG(254, PRGArea.AreaC000);
		Switch08KPRG(PRG_ROM_08KB_Mask, PRGArea.AreaE000);
	}

	internal override void WritePRG(ref ushort address, ref byte data)
	{
		switch (address)
		{
		case 32768:
			Switch08KPRG(data, PRGArea.Area8000);
			break;
		case 36865:
			Switch01KNMTFromMirroring(((data & 0x80) == 128) ? Mirroring.Horz : Mirroring.Vert);
			break;
		case 36867:
			irq_enable = (data & 0x80) == 128;
			NesEmu.IRQFlags &= -9;
			break;
		case 36868:
			irq_counter = irq_reload;
			NesEmu.IRQFlags &= -9;
			break;
		case 36869:
			irq_reload = (irq_reload & 0xFF) | (data << 8);
			break;
		case 36870:
			irq_reload = (irq_reload & 0xFF00) | data;
			break;
		case 40960:
			Switch08KPRG(data, PRGArea.AreaA000);
			break;
		case 49152:
			Switch08KPRG(data, PRGArea.AreaC000);
			break;
		case 45056:
			Switch01KCHR(data, CHRArea.Area0000);
			break;
		case 45057:
			Switch01KCHR(data, CHRArea.Area0400);
			break;
		case 45058:
			Switch01KCHR(data, CHRArea.Area0800);
			break;
		case 45059:
			Switch01KCHR(data, CHRArea.Area0C00);
			break;
		case 45060:
			Switch01KCHR(data, CHRArea.Area1000);
			break;
		case 45061:
			Switch01KCHR(data, CHRArea.Area1400);
			break;
		case 45062:
			Switch01KCHR(data, CHRArea.Area1800);
			break;
		case 45063:
			Switch01KCHR(data, CHRArea.Area1C00);
			break;
		}
	}

	internal override void OnCPUClock()
	{
		if (irq_enable)
		{
			if (irq_counter > 0)
			{
				irq_counter--;
			}
			else if (irq_counter == 0)
			{
				irq_counter = -1;
				NesEmu.IRQFlags |= 8;
			}
		}
	}
}