using System.IO;

namespace MyNes.Core;

[BoardInfo("VRC6", 24)]
[WithExternalSound]
internal class Mapper024 : 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;

	private VRC6Pulse snd_1;

	private VRC6Pulse snd_2;

	private VRC6Sawtooth snd_3;

	private double[] audio_pulse_table;

	private double[] audio_tnd_table;

	internal override void Initialize(IRom rom)
	{
		base.Initialize(rom);
		snd_1 = new VRC6Pulse();
		snd_2 = new VRC6Pulse();
		snd_3 = new VRC6Sawtooth();
		audio_pulse_table = new double[32];
		for (int i = 0; i < 32; i++)
		{
			audio_pulse_table[i] = 95.52 / (8128.0 / (double)i + 100.0);
		}
		audio_tnd_table = new double[204];
		for (int j = 0; j < 204; j++)
		{
			audio_tnd_table[j] = 163.67 / (24329.0 / (double)j + 100.0);
		}
	}

	internal override void HardReset()
	{
		base.HardReset();
		Switch08KPRG(PRG_ROM_08KB_Mask, PRGArea.AreaE000);
		APUApplyChannelsSettings();
		snd_1.HardReset();
		snd_2.HardReset();
		snd_3.HardReset();
	}

	internal override void WritePRG(ref ushort address, ref byte data)
	{
		switch (address)
		{
		case 32768:
		case 32769:
		case 32770:
		case 32771:
			Switch16KPRG(data, PRGArea.Area8000);
			break;
		case 36864:
			snd_1.Write0(ref data);
			break;
		case 36865:
			snd_1.Write1(ref data);
			break;
		case 36866:
			snd_1.Write2(ref data);
			break;
		case 40960:
			snd_2.Write0(ref data);
			break;
		case 40961:
			snd_2.Write1(ref data);
			break;
		case 40962:
			snd_2.Write2(ref data);
			break;
		case 45056:
			snd_3.Write0(ref data);
			break;
		case 45057:
			snd_3.Write1(ref data);
			break;
		case 45058:
			snd_3.Write2(ref data);
			break;
		case 45059:
			switch ((data & 0xC) >> 2)
			{
			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 49152:
		case 49153:
		case 49154:
		case 49155:
			Switch08KPRG(data, PRGArea.AreaC000);
			break;
		case 53248:
			Switch01KCHR(data, CHRArea.Area0000);
			break;
		case 53249:
			Switch01KCHR(data, CHRArea.Area0400);
			break;
		case 53250:
			Switch01KCHR(data, CHRArea.Area0800);
			break;
		case 53251:
			Switch01KCHR(data, CHRArea.Area0C00);
			break;
		case 57344:
			Switch01KCHR(data, CHRArea.Area1000);
			break;
		case 57345:
			Switch01KCHR(data, CHRArea.Area1400);
			break;
		case 57346:
			Switch01KCHR(data, CHRArea.Area1800);
			break;
		case 57347:
			Switch01KCHR(data, CHRArea.Area1C00);
			break;
		case 61440:
			irq_reload = data;
			break;
		case 61441:
			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 61442:
			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 OnAPUClockSingle()
	{
		base.OnAPUClockSingle();
		snd_1.ClockSingle();
		snd_2.ClockSingle();
		snd_3.ClockSingle();
	}

	internal override void APUApplyChannelsSettings()
	{
		base.APUApplyChannelsSettings();
		snd_1.Outputable = MyNesMain.RendererSettings.Audio_ChannelEnabled_VRC6_SQ1;
		snd_2.Outputable = MyNesMain.RendererSettings.Audio_ChannelEnabled_VRC6_SQ2;
		snd_3.Outputable = MyNesMain.RendererSettings.Audio_ChannelEnabled_VRC6_SAW;
	}

	internal override double APUGetSample()
	{
		return audio_pulse_table[snd_1.output + snd_2.output] + audio_tnd_table[snd_3.output];
	}

	internal override void WriteStateData(ref BinaryWriter stream)
	{
		base.WriteStateData(ref stream);
		stream.Write(irq_reload);
		stream.Write(irq_counter);
		stream.Write(prescaler);
		stream.Write(irq_mode_cycle);
		stream.Write(irq_enable);
		stream.Write(irq_enable_on_ak);
		snd_1.SaveState(ref stream);
		snd_2.SaveState(ref stream);
		snd_3.SaveState(ref stream);
	}

	internal override void ReadStateData(ref BinaryReader stream)
	{
		base.ReadStateData(ref stream);
		irq_reload = stream.ReadInt32();
		irq_counter = stream.ReadInt32();
		prescaler = stream.ReadInt32();
		irq_mode_cycle = stream.ReadBoolean();
		irq_enable = stream.ReadBoolean();
		irq_enable_on_ak = stream.ReadBoolean();
		snd_1.LoadState(ref stream);
		snd_2.LoadState(ref stream);
		snd_3.LoadState(ref stream);
	}
}