using System.IO;

namespace MyNes.Core;

[BoardInfo("VRC7", 85)]
[HassIssues]
internal class Mapper085 : Board
{
	private int irq_reload;

	private int irq_counter;

	private int prescaler;

	private bool irq_mode_cycle;

	private bool irq_enable;

	private bool irq_enable_on_ak;

	internal override string Issues => MNInterfaceLanguage.IssueMapper85;

	internal override void HardReset()
	{
		base.HardReset();
		Switch08KPRG(PRG_ROM_08KB_Mask, PRGArea.AreaE000);
		irq_reload = 0;
		prescaler = 341;
		irq_counter = 0;
		irq_mode_cycle = false;
		irq_enable = false;
		irq_enable_on_ak = false;
	}

	internal override void WritePRG(ref ushort address, ref byte data)
	{
		switch (address)
		{
		case 32768:
			Switch08KPRG(data, PRGArea.Area8000);
			break;
		case 32776:
		case 32784:
			Switch08KPRG(data, PRGArea.AreaA000);
			break;
		case 36864:
			Switch08KPRG(data, PRGArea.AreaC000);
			break;
		case 40960:
			Switch01KCHR(data, CHRArea.Area0000);
			break;
		case 40968:
		case 40976:
			Switch01KCHR(data, CHRArea.Area0400);
			break;
		case 45056:
			Switch01KCHR(data, CHRArea.Area0800);
			break;
		case 45064:
		case 45072:
			Switch01KCHR(data, CHRArea.Area0C00);
			break;
		case 49152:
			Switch01KCHR(data, CHRArea.Area1000);
			break;
		case 49160:
		case 49168:
			Switch01KCHR(data, CHRArea.Area1400);
			break;
		case 53248:
			Switch01KCHR(data, CHRArea.Area1800);
			break;
		case 53256:
		case 53264:
			Switch01KCHR(data, CHRArea.Area1C00);
			break;
		case 57344:
			switch (data & 3)
			{
			case 0:
				Switch01KNMTFromMirroring(Mirroring.Vert);
				break;
			case 1:
				Switch01KNMTFromMirroring(Mirroring.Horz);
				break;
			case 2:
				Switch01KNMTFromMirroring(Mirroring.OneScA);
				break;
			case 3:
				Switch01KNMTFromMirroring(Mirroring.OneScB);
				break;
			}
			break;
		case 57352:
		case 57360:
			irq_reload = data;
			break;
		case 61440:
			irq_mode_cycle = (data & 4) == 4;
			irq_enable = (data & 2) == 2;
			irq_enable_on_ak = (data & 1) == 1;
			if (irq_enable)
			{
				irq_counter = irq_reload;
				prescaler = 341;
			}
			NesEmu.IRQFlags &= -9;
			break;
		case 61448:
		case 61456:
			NesEmu.IRQFlags &= -9;
			irq_enable = irq_enable_on_ak;
			break;
		}
	}

	internal override void OnCPUClock()
	{
		if (!irq_enable)
		{
			return;
		}
		if (!irq_mode_cycle)
		{
			if (prescaler > 0)
			{
				prescaler -= 3;
				return;
			}
			prescaler = 341;
			irq_counter++;
			if (irq_counter == 255)
			{
				NesEmu.IRQFlags |= 8;
				irq_counter = irq_reload;
			}
		}
		else
		{
			irq_counter++;
			if (irq_counter == 255)
			{
				NesEmu.IRQFlags |= 8;
				irq_counter = irq_reload;
			}
		}
	}

	internal override void WriteStateData(ref BinaryWriter stream)
	{
		base.WriteStateData(ref stream);
		stream.Write(prescaler);
		stream.Write(irq_counter);
		stream.Write(irq_mode_cycle);
		stream.Write(irq_reload);
		stream.Write(irq_enable);
		stream.Write(irq_enable_on_ak);
	}

	internal override void ReadStateData(ref BinaryReader stream)
	{
		base.ReadStateData(ref stream);
		prescaler = stream.ReadInt32();
		irq_counter = stream.ReadInt32();
		irq_mode_cycle = stream.ReadBoolean();
		irq_reload = stream.ReadInt32();
		irq_enable = stream.ReadBoolean();
		irq_enable_on_ak = stream.ReadBoolean();
	}
}