//////////////////////////////////////////////////////////////////////////
// Mapper004  Supor Computer V4.0                                       //
//////////////////////////////////////////////////////////////////////////
using static VirtualNes.MMU;
using static VirtualNes.Core.CPU;
using INT = System.Int32;
using BYTE = System.Byte;
using System;
//using Codice.CM.Client.Differences;

namespace VirtualNes.Core
{
    public class Mapper167 : Mapper
    {
        BYTE[] regs = new byte[4];
        BYTE rom_type;
        public Mapper167(NES parent) : base(parent)
        {
        }

        public override void Reset()
        {
            uint crc;

            regs[0] = 0;
            regs[1] = 0;
            regs[2] = 0;
            regs[3] = 0;

            crc = nes.rom.GetPROM_CRC();
            if (crc == 0x82F1Fb96)
            {
                // Subor Computer(Russia)
                rom_type = 1;
            }
            else
            {
                // Subor Computer(Chinese)
                rom_type = 0;
            }

            SetBank_CPU();
            SetBank_PPU();
        }

        //void Mapper167::Write(WORD addr, BYTE data)
        public override void Write(ushort addr, byte data)
        {
            int idx;

            idx = (addr >> 13) & 0x03;
            regs[idx] = data;
            SetBank_CPU();
            SetBank_PPU();
            //	DEBUGOUT("write to %04x:%02x\n", addr, data);
        }


        void SetBank_CPU()
        {
            int @base, bank;

            @base = ((regs[0] ^ regs[1]) & 0x10) << 1;
            bank = (regs[2] ^ regs[3]) & 0x1f;

            if ((regs[1] & 0x08) != 0)
            {
                bank &= 0xfe;
                if (rom_type == 0)
                {
                    SetPROM_16K_Bank(4, @base + bank + 1);
                    SetPROM_16K_Bank(6, @base + bank + 0);
                }
                else
                {
                    SetPROM_16K_Bank(6, @base + bank + 1);
                    SetPROM_16K_Bank(4, @base + bank + 0);
                }
                //		DEBUGOUT("32K MODE!\n");
            }
            else
            {
                if ((regs[1] & 0x04) != 0)
                {
                    SetPROM_16K_Bank(4, 0x1f);
                    SetPROM_16K_Bank(6, @base + bank);
                    //			DEBUGOUT("HIGH 16K MODE!\n");
                }
                else
                {
                    SetPROM_16K_Bank(4, @base + bank);
                    if (rom_type == 0)
                    {
                        SetPROM_16K_Bank(6, 0x20);
                    }
                    else
                    {
                        SetPROM_16K_Bank(6, 0x07);
                    }
                    //			DEBUGOUT("LOW  16K MODE!\n");
                }
            }


        }

        void SetBank_PPU()
        {
            SetCRAM_8K_Bank(0);
        }

        //void Mapper167::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            p[0] = regs[0];
            p[1] = regs[1];
            p[2] = regs[2];
            p[3] = regs[3];
            p[4] = rom_type;
        }

        //void Mapper167::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            regs[0] = p[0];
            regs[1] = p[1];
            regs[2] = p[2];
            regs[3] = p[3];
            rom_type = p[4];
        }

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