//////////////////////////////////////////////////////////////////////////
// Mapper067  SunSoft Mapper 3                                          //
//////////////////////////////////////////////////////////////////////////
using System;
using static VirtualNes.Core.CPU;
using static VirtualNes.MMU;
using BYTE = System.Byte;
using INT = System.Int32;


namespace VirtualNes.Core
{
    public class Mapper067 : Mapper
    {
        BYTE irq_enable;
        BYTE irq_occur;
        BYTE irq_toggle;
        INT irq_counter;
        public Mapper067(NES parent) : base(parent)
        {
        }

        public override void Reset()

        {
            irq_enable = 0;
            irq_toggle = 0;
            irq_counter = 0;
            irq_occur = 0;

            SetPROM_32K_Bank(0, 1, PROM_8K_SIZE - 2, PROM_8K_SIZE - 1);

            SetVROM_4K_Bank(0, 0);
            SetVROM_4K_Bank(4, VROM_4K_SIZE - 1);

            uint crc = nes.rom.GetPROM_CRC();

            if (crc == 0x7f2a04bf)
            {   // For Fantasy Zone 2(J)
                nes.SetRenderMethod(EnumRenderMethod.PRE_ALL_RENDER);
            }
        }

        //void Mapper067::Write(WORD addr, BYTE data)
        public override void Write(ushort addr, byte data)
        {
            switch (addr & 0xF800)
            {
                case 0x8800:
                    SetVROM_2K_Bank(0, data);
                    break;
                case 0x9800:
                    SetVROM_2K_Bank(2, data);
                    break;
                case 0xA800:
                    SetVROM_2K_Bank(4, data);
                    break;
                case 0xB800:
                    SetVROM_2K_Bank(6, data);
                    break;

                case 0xC800:
                    if (irq_toggle == 0)
                    {
                        irq_counter = (irq_counter & 0x00FF) | ((INT)data << 8);
                    }
                    else
                    {
                        irq_counter = (irq_counter & 0xFF00) | ((INT)data & 0xFF);
                    }
                    irq_toggle ^= 1;
                    irq_occur = 0;
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;
                case 0xD800:
                    irq_enable = (byte)(data & 0x10);
                    irq_toggle = 0;
                    irq_occur = 0;
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;

                case 0xE800:
                    data &= 0x03;
                    if (data == 0) SetVRAM_Mirror(VRAM_VMIRROR);
                    else if (data == 1) SetVRAM_Mirror(VRAM_HMIRROR);
                    else if (data == 2) SetVRAM_Mirror(VRAM_MIRROR4L);
                    else SetVRAM_Mirror(VRAM_MIRROR4H);
                    break;

                case 0xF800:
                    SetPROM_16K_Bank(4, data);
                    break;
            }
        }

        //void Mapper067::Clock(INT cycles)
        public override void Clock(int cycles)
        {
            if (irq_enable != 0)
            {
                if ((irq_counter -= cycles) <= 0)
                {
                    irq_enable = 0;
                    irq_occur = 0xFF;
                    irq_counter = 0xFFFF;
                    nes.cpu.SetIRQ(IRQ_MAPPER);
                }
            }

            //	if( irq_occur ) {
            //		nes.cpu.IRQ_NotPending();
            //	}
        }

        //void Mapper067::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            p[0] = irq_enable;
            p[1] = irq_occur;
            p[2] = irq_toggle;
            //*((INT*)&p[3]) = irq_counter;
            BitConverter.GetBytes(irq_counter).CopyTo(p, 3);
        }

        //void Mapper067::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            irq_enable = p[0];
            irq_occur = p[1];
            irq_toggle = p[2];
            //irq_counter = *((INT*)&p[3]);
            irq_counter = BitConverter.ToInt32(p, 3);
        }


        public override bool IsStateSave()
        {
            return true;
        }

    }
}