using System.IO;

namespace MyNes.Core;

internal abstract class Bandai : Board
{
	private bool irq_enable;

	private int irq_counter;

	private Eprom eprom;

	internal override void Initialize(IRom rom)
	{
		base.Initialize(rom);
		if (base.BoardType.ToLower().Contains("24c01"))
		{
			eprom = new Eprom(128);
		}
		else
		{
			eprom = new Eprom((base.MapperNumber == 16) ? 256 : 128);
		}
	}

	internal override void HardReset()
	{
		base.HardReset();
		Switch16KPRG(PRG_ROM_16KB_Mask, PRGArea.AreaC000);
		irq_enable = false;
		irq_counter = 0;
		eprom.HardReset();
	}

	internal override void WriteSRM(ref ushort address, ref byte data)
	{
		WritePRG(ref address, ref data);
	}

	internal override void WritePRG(ref ushort address, ref byte data)
	{
		switch (address & 0xF)
		{
		case 0:
			Switch01KCHR(data, CHRArea.Area0000);
			break;
		case 1:
			Switch01KCHR(data, CHRArea.Area0400);
			break;
		case 2:
			Switch01KCHR(data, CHRArea.Area0800);
			break;
		case 3:
			Switch01KCHR(data, CHRArea.Area0C00);
			break;
		case 4:
			Switch01KCHR(data, CHRArea.Area1000);
			break;
		case 5:
			Switch01KCHR(data, CHRArea.Area1400);
			break;
		case 6:
			Switch01KCHR(data, CHRArea.Area1800);
			break;
		case 7:
			Switch01KCHR(data, CHRArea.Area1C00);
			break;
		case 8:
			Switch16KPRG(data, PRGArea.Area8000);
			break;
		case 9:
			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 10:
			irq_enable = (data & 1) == 1;
			NesEmu.IRQFlags &= -9;
			break;
		case 11:
			irq_counter = (irq_counter & 0xFF00) | data;
			break;
		case 12:
			irq_counter = (irq_counter & 0xFF) | (data << 8);
			break;
		case 13:
			eprom.Write(address, data);
			break;
		}
	}

	internal override void ReadSRM(ref ushort address, out byte value)
	{
		value = eprom.Read(address);
	}

	internal override void OnCPUClock()
	{
		if (irq_enable)
		{
			irq_counter--;
			if (irq_counter == 0)
			{
				NesEmu.IRQFlags |= 8;
			}
			if (irq_counter < 0)
			{
				irq_counter = 65535;
			}
		}
	}

	internal override void WriteStateData(ref BinaryWriter stream)
	{
		base.WriteStateData(ref stream);
		stream.Write(irq_enable);
		stream.Write(irq_counter);
		eprom.SaveState(stream);
	}

	internal override void ReadStateData(ref BinaryReader stream)
	{
		base.ReadStateData(ref stream);
		irq_enable = stream.ReadBoolean();
		irq_counter = stream.ReadInt32();
		eprom.LoadState(stream);
	}
}