//////////////////////////////////////////////////////////////////////////
// Mapper109 SACHEN The Great Wall SA-019                               //
//////////////////////////////////////////////////////////////////////////
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 Mapper109 : Mapper
	{

		BYTE reg;
		BYTE chr0, chr1, chr2, chr3;
		BYTE chrmode0, chrmode1;
		public Mapper109(NES parent) : base(parent)
		{
		}

		public override void Reset()
		{
			reg = 0;
			SetPROM_32K_Bank(0);

			chr0 = 0;
			chr1 = 0;
			chr2 = 0;
			chr3 = 0;
			SetBank_PPU();
			chrmode0 = 0;
			chrmode1 = 0;
		}

		//void Mapper109::WriteLow(WORD addr, BYTE data)
		public override void WriteLow(ushort addr, byte data)
		{
			switch (addr)
			{
				case 0x4100:
					reg = data;
					break;
				case 0x4101:
					switch (reg)
					{
						case 0:
							chr0 = data;
							SetBank_PPU();
							break;
						case 1:
							chr1 = data;
							SetBank_PPU();
							break;
						case 2:
							chr2 = data;
							SetBank_PPU();
							break;
						case 3:
							chr3 = data;
							SetBank_PPU();
							break;
						case 4:
							chrmode0 = (byte)(data & 0x01);
							SetBank_PPU();
							break;
						case 5:
							SetPROM_32K_Bank(data & 0x07);
							break;
						case 6:
							chrmode1 = (byte)(data & 0x07);
							SetBank_PPU();
							break;
						case 7:
							if ((data & 0x01) != 0) SetVRAM_Mirror(VRAM_HMIRROR);
							else SetVRAM_Mirror(VRAM_VMIRROR);
							break;
					}
					break;
			}

		}

		void SetBank_PPU()
		{
			if (VROM_1K_SIZE != 0)
			{
				SetVROM_1K_Bank(0, chr0);
				SetVROM_1K_Bank(1, chr1 | ((chrmode1 << 3) & 0x8));
				SetVROM_1K_Bank(2, chr2 | ((chrmode1 << 2) & 0x8));
				SetVROM_1K_Bank(3, chr3 | ((chrmode1 << 1) & 0x8) | (chrmode0 * 0x10));
				SetVROM_1K_Bank(4, VROM_1K_SIZE - 4);
				SetVROM_1K_Bank(5, VROM_1K_SIZE - 3);
				SetVROM_1K_Bank(6, VROM_1K_SIZE - 2);
				SetVROM_1K_Bank(7, VROM_1K_SIZE - 1);
			}
		}

		//void Mapper109::SaveState(LPBYTE p)
		public override void SaveState(byte[] p)
		{
			p[0] = reg;
			p[1] = chr0;
			p[2] = chr1;
			p[3] = chr2;
			p[4] = chr3;
			p[5] = chrmode0;
			p[6] = chrmode1;
		}

		//void Mapper109::LoadState(LPBYTE p)
		public override void LoadState(byte[] p)
		{
			reg = p[0];
			chr0 = p[1];
			chr1 = p[2];
			chr2 = p[3];
			chr3 = p[4];
			chrmode0 = p[5];
			chrmode1 = p[6];
		}


		public override bool IsStateSave()
		{
			return true;
		}

	}
}