using System;
using System.Collections.Generic;
using BizHawk.Common;

namespace BizHawk.Emulation.Cores.Computers.Commodore64.Cartridge
{
    public abstract partial class CartridgeDevice
    {
        private sealed class Mapper0012 : CartridgeDevice
        {
            [SaveState.DoNotSave]
            private readonly int[] _bankMain;
            [SaveState.DoNotSave]
            private readonly int[][] _bankHigh;
            [SaveState.SaveWithName("BankHighSelected")]
            private int[] _bankHighSelected;
            [SaveState.SaveWithName("BankIndex")]
            private int _bankIndex;

            // Zaxxon and Super Zaxxon cartridges
            // - read to 8xxx selects bank 0 in A000-BFFF
            // - read to 9xxx selects bank 1 in A000-BFFF

            public Mapper0012(IList<int> newAddresses, IList<int> newBanks, IList<int[]> newData)
            {
                _bankMain = new int[0x2000];
                _bankHigh = new int[2][];
                var dummyBank = new int[0x2000];

                // create dummy bank just in case
                for (var i = 0; i < 0x2000; i++)
                    dummyBank[i] = 0xFF;

                _bankHigh[0] = dummyBank;
                _bankHigh[1] = dummyBank;

                // load in the banks
                for (var i = 0; i < newAddresses.Count; i++)
                {
                    if (newAddresses[i] == 0x8000)
                        Array.Copy(newData[i], _bankMain, 0x1000);
                    else if ((newAddresses[i] == 0xA000 || newAddresses[i] == 0xE000) && newBanks[i] < 2)
                        _bankHigh[newBanks[i]] = newData[i];
                }

                // mirror the main rom from 8000 to 9000
                Array.Copy(_bankMain, 0x0000, _bankMain, 0x1000, 0x1000);

                // set both pins low for 16k rom config
                pinExRom = false;
                pinGame = false;

            }

            public override int Peek8000(int addr)
            {
                return _bankMain[addr];
            }

            public override int PeekA000(int addr)
            {
                return _bankHighSelected[addr];
            }

            public override int Read8000(int addr)
            {
                _bankIndex = (addr & 0x1000) >> 12;
                _bankHighSelected = _bankHigh[_bankIndex];
                return _bankMain[addr];
            }

            public override int ReadA000(int addr)
            {
                return _bankHighSelected[addr];
            }

            public override void SyncState(Serializer ser)
            {
                base.SyncState(ser);
                if (ser.IsReader)
                    _bankHighSelected = _bankHigh[_bankIndex];
            }
        }

    }
}