//////////////////////////////////////////////////////////////////////////
// Mapper199  WaiXingTypeG Base ON Nintendo MMC3                        //
//////////////////////////////////////////////////////////////////////////
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 Mapper199 : Mapper
    {
        BYTE[] reg = new byte[8];
        BYTE[] prg = new byte[4];
        BYTE[] chr = new byte[8];
        BYTE we_sram;

        BYTE irq_type;
        BYTE irq_enable;
        BYTE irq_counter;
        BYTE irq_latch;
        BYTE irq_request;
        public Mapper199(NES parent) : base(parent)
        {
        }

        public override void Reset()
        {
            for (INT i = 0; i < 8; i++)
            {
                reg[i] = 0x00;
                chr[i] = (byte)i;
            }
            prg[0] = 0x00;
            prg[1] = 0x01;
            prg[2] = 0x3e;
            prg[3] = 0x3f;
            SetBank_CPU();
            SetBank_PPU();

            we_sram = 0;
            irq_enable = irq_counter = irq_latch = irq_request = 0;


            uint crcP = nes.rom.GetPROM_CRC();
            uint crcV = nes.rom.GetVROM_CRC();

            if ((crcP == 0xE80D8741) || (crcV == 0x3846520D))
            {//ÍâÐÇ°ÔÍõµÄ´ó½
                nes.SetRenderMethod(EnumRenderMethod.POST_ALL_RENDER);
            }
        }


        //BYTE Mapper199::ReadLow(WORD addr)
        public override byte ReadLow(ushort addr)
        {
            if (addr >= 0x5000 && addr <= 0x5FFF)
            {
                return XRAM[addr - 0x4000];
            }
            else
            {
                return base.ReadLow(addr);
            }
        }

        //void Mapper199::WriteLow(WORD addr, BYTE data)
        public override void WriteLow(ushort addr, byte data)
        {
            if (addr >= 0x5000 && addr <= 0x5FFF)
            {
                XRAM[addr - 0x4000] = data;
            }
            else
            {
                base.WriteLow(addr, data);
            }
        }

        //void Mapper199::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 & 0xE001)
            {
                case 0x8000:
                    reg[0] = data;
                    SetBank_CPU();
                    SetBank_PPU();
                    break;
                case 0x8001:
                    reg[1] = data;

                    switch (reg[0] & 0x0f)
                    {
                        case 0x00: chr[0] = data; SetBank_PPU(); break;
                        case 0x01: chr[2] = data; SetBank_PPU(); break;
                        case 0x02:
                        case 0x03:
                        case 0x04:
                        case 0x05: chr[(reg[0] & 0x07) + 2] = data; SetBank_PPU(); break;
                        case 0x06:
                        case 0x07:
                        case 0x08:
                        case 0x09: prg[(reg[0] & 0x0f) - 6] = data; SetBank_CPU(); break;
                        case 0x0A: chr[1] = data; SetBank_PPU(); break;
                        case 0x0B: chr[3] = data; SetBank_PPU(); break;
                    }
                    break;
                case 0xA000:
                    reg[2] = data;
                    //if( !nes.rom.Is4SCREEN() ) 
                    {
                        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 0xA001:
                    reg[3] = data;
                    break;
                case 0xC000:
                    reg[4] = data;
                    irq_counter = data;
                    irq_request = 0;
                    break;
                case 0xC001:
                    reg[5] = data;
                    irq_latch = data;
                    irq_request = 0;
                    break;
                case 0xE000:
                    reg[6] = data;
                    irq_enable = 0;
                    irq_request = 0;
                    nes.cpu.ClrIRQ(IRQ_MAPPER);
                    break;
                case 0xE001:
                    reg[7] = data;
                    irq_enable = 1;
                    irq_request = 0;
                    break;
            }

        }

        //void Mapper199::HSync(INT scanline)
        public override void HSync(int scanline)
        {
            if ((scanline >= 0 && scanline <= 239))
            {
                if (nes.ppu.IsDispON())
                {
                    if (irq_enable != 0 && irq_request == 0)
                    {
                        if (scanline == 0)
                        {
                            if (irq_counter != 0)
                            {
                                irq_counter--;
                            }
                        }
                        if ((irq_counter--) == 0)
                        {
                            irq_request = 0xFF;
                            irq_counter = irq_latch;
                            nes.cpu.SetIRQ(IRQ_MAPPER);
                        }
                    }
                }
            }
        }

        void SetBank_CPU()
        {
            SetPROM_8K_Bank(4, prg[0 ^ (reg[0] >> 5 & ~(0 << 1) & 2)]);
            SetPROM_8K_Bank(5, prg[1 ^ (reg[0] >> 5 & ~(1 << 1) & 2)]);
            SetPROM_8K_Bank(6, prg[2 ^ (reg[0] >> 5 & ~(2 << 1) & 2)]);
            SetPROM_8K_Bank(7, prg[3 ^ (reg[0] >> 5 & ~(3 << 1) & 2)]);
        }

        void SetBank_PPU()
        {
            //unsigned int bank = (reg[0] & 0x80) >> 5;
            int bank = (reg[0] & 0x80) >> 5;
            for (int x = 0; x < 8; x++)
            {
                if (chr[x] <= 7)
                {
                    SetCRAM_1K_Bank((byte)(x ^ bank), chr[x]);
                }
                else
                {
                    SetVROM_1K_Bank((byte)(x ^ bank), chr[x]);
                }
            }
        }

        //void Mapper199::SaveState(LPBYTE p)
        public override void SaveState(byte[] p)
        {
            for (INT i = 0; i < 8; i++)
            {
                p[i] = reg[i];
                p[10 + i] = chr[i];
            }

            p[8] = prg[0];
            p[9] = prg[1];
            p[18] = irq_enable;
            p[19] = irq_counter;
            p[20] = irq_latch;
            p[21] = irq_request;
            p[22] = prg[2];
            p[23] = prg[3];
        }

        //void Mapper199::LoadState(LPBYTE p)
        public override void LoadState(byte[] p)
        {
            for (INT i = 0; i < 8; i++)
            {
                reg[i] = p[i];
                chr[i] = p[10 + i];
            }
            prg[0] = p[8];
            prg[1] = p[9];
            irq_enable = p[18];
            irq_counter = p[19];
            irq_latch = p[20];
            irq_request = p[21];
            prg[2] = p[22];
            prg[3] = p[23];
        }

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