//////////////////////////////////////////////////////////////////////////
// Mapper168          Subor (PPUExtLatch)                               //
//////////////////////////////////////////////////////////////////////////
using VirtualNes.Core.Debug;
using static VirtualNes.MMU;
using BYTE = System.Byte;
using INT = System.Int32;

namespace VirtualNes.Core
{
    public class Mapper168 : Mapper
    {
        byte reg5000, reg5200, reg5300;
        byte PPU_SW, NT_data;
        byte Rom_Type;
        public Mapper168(NES parent) : base(parent) { }

        public override bool IsStateSave()
        {
            return true;
        }
        public override void Reset()
        {
            reg5000 = 0;
            reg5200 = 0;
            reg5300 = 0;
            PPU_SW = 0;
            NT_data = 0;
            nes.ppu.SetExtLatchMode(true);
            SetPROM_16K_Bank(4, 0);
            SetPROM_16K_Bank(6, 0);

            Rom_Type = 0;
            uint crc = nes.rom.GetPROM_CRC();
            if (crc == 0x0A9808AE)      //[Subor] Karaoke (C)
            {
                Rom_Type = 1;
                SetPROM_32K_Bank(0);
                nes.SetVideoMode(2 != 0);
            }
            if (crc == 0x12D61CE8)      //[Subor] Subor V11.0 (C)
            {
                Rom_Type = 2;
            }
        }

        public override byte ReadLow(ushort addr)
        {
            if (addr == 0x5300) return 0x8F;    //返回0x8F，跳过真人语音发声有关的程序段
            return base.ReadLow(addr);
        }

        public override void WriteLow(ushort addr, byte data)
        {
            if (addr == 0x5000)
            {
                reg5000 = data;
                SetBank_CPU();
            }
            else if (addr == 0x5200)
            {
                reg5200 = (byte)(data & 0x7);
                SetBank_CPU();
            }
            else if (addr == 0x5300)
            {
                reg5300 = data;
            }
            else if (addr >= 0x6000)
            {
                CPU_MEM_BANK[addr >> 13][addr & 0x1FFF] = data;
            }
        }


        public override void Write(ushort addr, byte data)
        {
            if (Rom_Type == 1)
            {   //[Subor] Karaoke (C)
                SetPROM_32K_Bank(data & 0x1F);
                if ((data & 0x40) != 0) SetVRAM_Mirror(VRAM_HMIRROR);
                else SetVRAM_Mirror(VRAM_VMIRROR);
                if ((data & 0xC0) != 0) PPU_SW = 1;
                else PPU_SW = 0;
            }
        }

        void SetBank_CPU()
        {
            if (reg5200 < 4) SetPROM_16K_Bank(4, reg5000);
            else SetPROM_32K_Bank(reg5000);
            switch (reg5200)
            {
                case 0:
                    SetVRAM_Mirror(VRAM_VMIRROR);
                    PPU_SW = 0;
                    break;
                case 2:
                    SetVRAM_Mirror(VRAM_VMIRROR);
                    PPU_SW = 1;
                    break;
                case 1:
                case 3:
                    SetVRAM_Mirror(VRAM_HMIRROR);
                    PPU_SW = 0;
                    break;
                case 5:
                    if (reg5000 == 4 && Rom_Type == 2)
                    {   //Special for [Subor] Subor V11.0 (C) - Tank (坦克大战)
                        nes.ppu.SetExtLatchMode(false);
                        SetVRAM_Mirror(VRAM_HMIRROR);
                    }
                    break;
            }
        }

        public override void PPU_Latch(ushort addr)
        {
            if ((addr & 0xF000) == 0x2000)
            {
                NT_data = (byte)((addr >> 8) & 0x03);
            }
        }

        public override void PPU_ExtLatch(ushort ntbladr, ref byte chr_l, ref byte chr_h, ref byte attr)
        {
            INT loopy_v = nes.ppu.GetPPUADDR();
            INT loopy_y = nes.ppu.GetTILEY();
            INT tileofs = (PPUREG[0] & PPU.PPU_BGTBL_BIT) << 8;
            INT attradr = 0x23C0 + (loopy_v & 0x0C00) + ((loopy_v & 0x0380) >> 4);
            INT attrsft = (ntbladr & 0x0040) >> 4;
            ArrayRef<byte> pNTBL = PPU_MEM_BANK[ntbladr >> 10];
            INT ntbl_x = ntbladr & 0x001F;
            INT tileadr, ntb;

            ntb = (ntbladr >> 10) & 3;

            if (ntb == 2)
                tileofs |= 0x1000;
            else if (ntb != 0 && PPU_SW != 0)
                tileofs |= 0x1000;
            else
                tileofs |= 0x0000;

            attradr &= 0x3FF;
            attr = (byte)(((pNTBL[attradr + (ntbl_x >> 2)] >> ((ntbl_x & 2) + attrsft)) & 3) << 2);
            tileadr = tileofs + pNTBL[ntbladr & 0x03FF] * 0x10 + loopy_y;

            chr_l = PPU_MEM_BANK[tileadr >> 10][tileadr & 0x03FF];
            chr_h = PPU_MEM_BANK[tileadr >> 10][(tileadr & 0x03FF) + 8];
        }

        public override void SaveState(byte[] p)
        {
            p[0] = reg5000;
            p[1] = reg5200;
        }

        public override void LoadState(byte[] p)
        {
            reg5000 = p[0];
            reg5200 = p[1];
        }

    }
}