//////////////////////////////////////////////////////////////////////////
// Mapper023  Konami VRC2 type B                                        //
//////////////////////////////////////////////////////////////////////////
using System;
using static VirtualNes.Core.CPU;
using static VirtualNes.MMU;
using BYTE = System.Byte;
using INT = System.Int32;


namespace VirtualNes.Core
{
    public class Mapper023 : Mapper
    {

        ushort addrmask;

        BYTE[] reg = new byte[9];
        BYTE irq_enable;
        BYTE irq_counter;
        BYTE irq_latch;
        INT irq_clock;
        public Mapper023(NES parent) : base(parent)
        {
        }


        public override void Reset()
        {
            addrmask = 0xFFFF;

            for (byte i = 0; i < 8; i++)
            {
                reg[i] = i;
            }
            reg[8] = 0;

            irq_enable = 0;
            irq_counter = 0;
            irq_latch = 0;
            irq_clock = 0;

            reg[9] = 1;

            SetPROM_32K_Bank(0, 1, PROM_8K_SIZE - 2, PROM_8K_SIZE - 1);
            SetVROM_8K_Bank(0);

            //	nes.SetRenderMethod( NES::POST_RENDER );

            uint crc = nes.rom.GetPROM_CRC();

            if (crc == 0x93794634       // Akumajou Special Boku Dracula Kun(J)
             || crc == 0xc7829dae       // Akumajou Special Boku Dracula Kun(T-Eng)
             || crc == 0xf82dc02f)
            {   // Akumajou Special Boku Dracula Kun(T-Eng v1.02)
                addrmask = 0xF00C;
                nes.SetRenderMethod(EnumRenderMethod.POST_ALL_RENDER);
            }
            if (crc == 0xdd53c4ae)
            {   // Tiny Toon Adventures(J)
                nes.SetRenderMethod(EnumRenderMethod.POST_ALL_RENDER);
            }
        }

        //void Mapper023::Write(WORD addr, BYTE data)
        public override void Write(ushort addr, byte data)
        {
            //DEBUGOUT( "MPRWR A=%04X D=%02X L=%3d CYC=%d\n", addr&0xFFFF, data&0xFF, nes.GetScanline(), nes.cpu.GetTotalCycles() );
            switch (addr & addrmask)
            {
                case 0x8000:
                case 0x8004:
                case 0x8008:
                case 0x800C:
                    if (reg[8] != 0)
                    {
                        SetPROM_8K_Bank(6, data);
                    }
                    else
                    {
                        SetPROM_8K_Bank(4, data);
                    }
                    break;

                case 0x9000:
                    if (data != 0xFF)
                    {
                        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 0x9008:
                    reg[8] = (byte)(data & 0x02);
                    break;

                case 0xA000:
                case 0xA004:
                case 0xA008:
                case 0xA00C:
                    SetPROM_8K_Bank(5, data);
                    break;

                case 0xB000:
                    reg[0] = (byte)((reg[0] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(0, reg[0]);
                    break;
                case 0xB001:
                case 0xB004:
                    reg[0] = ((byte)((reg[0] & 0x0F) | ((data & 0x0F) << 4)));
                    SetVROM_1K_Bank(0, reg[0]);
                    break;

                case 0xB002:
                case 0xB008:
                    reg[1] = (byte)((reg[1] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(1, reg[1]);
                    break;

                case 0xB003:
                case 0xB00C:
                    reg[1] = (byte)((reg[1] & 0x0F) | ((data & 0x0F) << 4));
                    SetVROM_1K_Bank(1, reg[1]);
                    break;

                case 0xC000:
                    reg[2] = (byte)((reg[2] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(2, reg[2]);
                    break;

                case 0xC001:
                case 0xC004:
                    reg[2] = (byte)((reg[2] & 0x0F) | ((data & 0x0F) << 4));
                    SetVROM_1K_Bank(2, reg[2]);
                    break;

                case 0xC002:
                case 0xC008:
                    reg[3] = (byte)((reg[3] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(3, reg[3]);
                    break;

                case 0xC003:
                case 0xC00C:
                    reg[3] = (byte)((reg[3] & 0x0F) | ((data & 0x0F) << 4));
                    SetVROM_1K_Bank(3, reg[3]);
                    break;

                case 0xD000:
                    reg[4] = (byte)((reg[4] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(4, reg[4]);
                    break;

                case 0xD001:
                case 0xD004:
                    reg[4] = (byte)((reg[4] & 0x0F) | ((data & 0x0F) << 4));
                    SetVROM_1K_Bank(4, reg[4]);
                    break;

                case 0xD002:
                case 0xD008:
                    reg[5] = (byte)((reg[5] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(5, reg[5]);
                    break;

                case 0xD003:
                case 0xD00C:
                    reg[5] = (byte)((reg[5] & 0x0F) | ((data & 0x0F) << 4));
                    SetVROM_1K_Bank(5, reg[5]);
                    break;

                case 0xE000:
                    reg[6] = (byte)((reg[6] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(6, reg[6]);
                    break;

                case 0xE001:
                case 0xE004:
                    reg[6] = (byte)((reg[6] & 0x0F) | ((data & 0x0F) << 4));
                    SetVROM_1K_Bank(6, reg[6]);
                    break;

                case 0xE002:
                case 0xE008:
                    reg[7] = (byte)((reg[7] & 0xF0) | (data & 0x0F));
                    SetVROM_1K_Bank(7, reg[7]);
                    break;

                case 0xE003:
                case 0xE00C:
                    reg[7] = ((byte)((reg[7] & 0x0F) | ((data & 0x0F) << 4)));
                    SetVROM_1K_Bank(7, reg[7]);
                    break;

                case 0xF000:
                    irq_latch = (byte)((irq_latch & 0xF0) | (data & 0x0F));
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;
                case 0xF004:
                    irq_latch = (byte)((irq_latch & 0x0F) | ((data & 0x0F) << 4));
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;

                case 0xF008:
                    irq_enable = (byte)(data & 0x03);
                    irq_counter = irq_latch;
                    irq_clock = 0;
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;

                case 0xF00C:
                    irq_enable = (byte)((irq_enable & 0x01) * 3);
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;
            }
        }

        //void Mapper023::Clock(INT cycles)
        public override void Clock(int cycles)
        {
            if ((irq_enable & 0x02) != 0)
            {
                irq_clock += cycles * 3;
                while (irq_clock >= 341)
                {
                    irq_clock -= 341;
                    irq_counter++;
                    if (irq_counter == 0)
                    {
                        irq_counter = irq_latch;
                        nes.cpu.SetIRQ(IRQ_MAPPER);
                    }
                }
            }
        }

        //void Mapper023::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            for (INT i = 0; i < 9; i++)
            {
                p[i] = reg[i];
            }
            p[9] = irq_enable;
            p[10] = irq_counter;
            p[11] = irq_latch;
            //*(INT*)&p[12] = irq_clock;
            BitConverter.GetBytes(irq_clock).CopyTo(p, 12);
        }

        //void Mapper023::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            for (INT i = 0; i < 9; i++)
            {
                reg[i] = p[i];
            }
            irq_enable = p[9];
            irq_counter = p[10];
            irq_latch = p[11];
            //irq_clock = *(INT*)&p[12];
            irq_clock = BitConverter.ToInt32(p, 12);
        }


        public override bool IsStateSave()
        {
            return true;
        }
    }
}