using System.IO;

namespace MyNes.Core
{
    internal class Sunsoft5BChnl
    {
    	internal bool Enabled;

    	internal byte Volume;

    	private int dutyStep = 0;

    	private int freqTimer;

    	private int frequency;

    	private int cycles;

    	internal int output;

    	internal bool Outputable;

    	internal void HardReset()
    	{
    	}

    	internal void SoftReset()
    	{
    	}

    	internal void Write0(ref byte data)
    	{
    		frequency = (frequency & 0xF00) | data;
    		freqTimer = (frequency + 1) * 2;
    	}

    	internal void Write1(ref byte data)
    	{
    		frequency = (frequency & 0xFF) | ((data & 0xF) << 8);
    		freqTimer = (frequency + 1) * 2;
    	}

    	internal void ClockSingle()
    	{
    		if (--cycles > 0)
    		{
    			return;
    		}
    		cycles = freqTimer;
    		dutyStep = (dutyStep + 1) & 0x1F;
    		if (dutyStep <= 15)
    		{
    			if (Enabled)
    			{
    				if (Outputable)
    				{
    					output = Volume;
    				}
    				else
    				{
    					output = 0;
    				}
    			}
    			else
    			{
    				output = 0;
    			}
    		}
    		else
    		{
    			output = 0;
    		}
    	}

    	internal void SaveState(ref BinaryWriter stream)
    	{
    		stream.Write(Enabled);
    		stream.Write(Volume);
    		stream.Write(dutyStep);
    		stream.Write(freqTimer);
    		stream.Write(frequency);
    		stream.Write(cycles);
    	}

    	internal void LoadState(ref BinaryReader stream)
    	{
    		Enabled = stream.ReadBoolean();
    		Volume = stream.ReadByte();
    		dutyStep = stream.ReadInt32();
    		freqTimer = stream.ReadInt32();
    		frequency = stream.ReadInt32();
    		cycles = stream.ReadInt32();
    	}
    }
}