using System;

namespace BizHawk.Emulation.Cores.Sega.Genesis
{
	partial class Genesis
	{
		public sbyte ReadByte(int address)
		{
			address &= 0x00FFFFFF;

			if (address < 0x200000)
				return (sbyte)RomData[address];

			if (address < 0x400000)
			{
				if (SaveRamEnabled && address >= SaveRamStartOffset && address < SaveRamEndOffset)
				{
					if (SaveRamEveryOtherByte)
						return (sbyte)SaveRAM[(address - SaveRamStartOffset) >> 1];
					else
						return (sbyte)SaveRAM[address - SaveRamStartOffset];
				}
				return (sbyte)RomData[address];
			}

			if (address >= 0xE00000)
				return (sbyte)Ram[address & 0xFFFF];

			if (address == 0xA11100) // Z80 BUS status
			{
				//Console.WriteLine("QUERY z80 bus status. 68000 can access? " + (M68000HasZ80Bus && Z80Reset == false));
				return (sbyte)(M68000HasZ80Bus && Z80Reset == false ? 0 : 1);
			}

			if (address >= 0xA10000 && address <= 0xA1001F)
				return (sbyte)ReadIO(address);

			if ((address & 0xFF0000) == 0xA00000)
				return (sbyte)ReadMemoryZ80((ushort)(address & 0x7FFF));

			if (address >= 0xC00000 && address < 0xC00010)
			{
				//Console.WriteLine("byte-reading the VDP. someone is probably stupid.");
				ushort value = VDP.ReadVdp(address & 0x0E);
				if ((address & 1) == 0) // read MSB
					return (sbyte)(value >> 8);
				return (sbyte)value; // read LSB
			}

			Console.WriteLine("UNHANDLED READB {0:X6}", address);
			return 0x7D;
		}

		public short ReadWord(int address)
		{
			address &= 0x00FFFFFF;

			int maskedAddr;
			if (address < 0x400000)
				return (short)((RomData[address] << 8) | RomData[address + 1]);

			if (address >= 0xE00000) // Work RAM
			{
				maskedAddr = address & 0xFFFE;
				return (short)((Ram[maskedAddr] << 8) | Ram[maskedAddr + 1]);
			}

			if (address >= 0xC00000 && address < 0xC00010)
				return (short)VDP.ReadVdp(address & 0x0E);

			if (address >= 0xA10000 && address <= 0xA1001F)
				return (sbyte)ReadIO(address);

			if (address == 0xA11100) // Z80 BUS status
				return (short)(M68000HasZ80Bus && Z80Reset == false ? 0x0000 : 0x0100);

			Console.WriteLine("UNHANDLED READW {0:X6}", address);
			return 0x7DCD;
		}

		public int ReadLong(int address)
		{
			address &= 0x00FFFFFF;

			int maskedAddr;
			if (address < 0x400000) // Cartridge ROM
				return (RomData[address] << 24) | (RomData[address + 1] << 16) | (RomData[address + 2] << 8) | RomData[address + 3];

			if (address >= 0xE00000) // Work RAM
			{
				maskedAddr = address & 0xFFFF;
				return (Ram[maskedAddr] << 24) | (Ram[maskedAddr + 1] << 16) | (Ram[maskedAddr + 2] << 8) | Ram[maskedAddr + 3];
			}

			if (address >= 0xC00000)
			{
				//Console.WriteLine("long-read from VDP");
				short msw = ReadWord(address);
				short msl = ReadWord(address + 2);
				return (msw << 16) | (ushort)msl;
			}

			// try to handle certain things separate if they need to be separate? otherwise handle as 2x readwords?
			{
				return ((ushort)ReadWord(address) | (ushort)(ReadWord(address + 2) << 16));
			}
			//if (address == 0xA10008) return 0; // FIXME HACK for tg-sync.

			//Console.WriteLine("UNHANDLED READL {0:X6}", address);
			//return 0x7DCDCDCD;
		}

		public void WriteByte(int address, sbyte value)
		{
			address &= 0x00FFFFFF;

			if (address >= 0xE00000) // Work RAM
			{
				//Console.WriteLine("MEM[{0:X4}] change from {1:X2} to {2:X2}", address & 0xFFFF, Ram[address & 0xFFFF], value);
				Ram[address & 0xFFFF] = (byte)value;
				return;
			}
			if ((address & 0xFF0000) == 0xA00000)
			{
				WriteMemoryZ80((ushort)(address & 0x7FFF), (byte)value);
				return;
			}
			if (address >= 0xA10000 && address <= 0xA1001F)
			{
				WriteIO(address, value);
				return;
			}
			if (address == 0xA11100)
			{
				M68000HasZ80Bus = (value & 1) != 0;
				//Console.WriteLine("68000 has the z80 bus: " + M68000HasZ80Bus);
				return;
			}
			if (address == 0xA11200) // Z80 RESET
			{
				Z80Reset = (value & 1) == 0;
				if (Z80Reset)
					SoundCPU.SoftReset();
				//Console.WriteLine("z80 reset: " + Z80Reset);
				return;
			}
			if (address >= 0xC00000 && address < 0xC00010)
			{
				// when writing to VDP in byte mode, the LSB is duplicated into the MSB
				VDP.WriteVdp(address & 0x1E, (ushort)((ushort)value | ((ushort)value << 8)));
				return;
			}
			if (address >= 0xC00011 && address <= 0xC00017 && (address & 1) != 0)
			{
				PSG.WritePsgData((byte)value, SoundCPU.TotalExecutedCycles);
				return;
			}

			if (SaveRamEnabled && address >= SaveRamStartOffset && address < SaveRamEndOffset)
			{
				if (SaveRamEveryOtherByte)
					SaveRAM[(address - SaveRamStartOffset) >> 1] = (byte)value;
				else
					SaveRAM[address - SaveRamStartOffset] = (byte)value;

				SaveRamModified = true;
				return;
			}

			if (EepromEnabled && (address == SclAddr || address == SdaInAddr))
			{
				WriteByteEeprom(address, (byte)value);
				return;

			}

			Console.WriteLine("UNHANDLED WRITEB {0:X6}:{1:X2}", address, value);
		}

		public void WriteWord(int address, short value)
		{
			address &= 0x00FFFFFF;

			if (address >= 0xE00000) // Work RAM
			{
				//Console.WriteLine("MEM[{0:X4}] change to {1:X4}", address & 0xFFFF, value);
				Ram[(address & 0xFFFF) + 0] = (byte)(value >> 8);
				Ram[(address & 0xFFFF) + 1] = (byte)value;
				return;
			}
			if (address >= 0xC00000)
			{
				switch (address & 0x1F)
				{
					case 0x00:
					case 0x02:
						VDP.WriteVdpData((ushort)value);
						return;
					case 0x04:
					case 0x06:
						VDP.WriteVdpControl((ushort)value);
						return;
				}
			}
			if (address == 0xA11100) // Z80 BUSREQ
			{
				M68000HasZ80Bus = (value & 0x100) != 0;
				//Console.WriteLine("68000 has the z80 bus: " + M68000HasZ80Bus);
				return;
			}
			if (address == 0xA11200) // Z80 RESET
			{
				Z80Reset = (value & 0x100) == 0;
				if (Z80Reset)
					SoundCPU.SoftReset();
				//Console.WriteLine("z80 reset: " + Z80Reset);
				return;
			}
			Console.WriteLine("UNHANDLED WRITEW {0:X6}:{1:X4}", address, value);
		}

		public void WriteLong(int address, int value)
		{
			address &= 0x00FFFFFF;

			if (address >= 0xE00000) // Work RAM
			{
				//Console.WriteLine("MEM[{0:X4}] change to {1:X8}", address & 0xFFFF, value);
				Ram[(address & 0xFFFF) + 0] = (byte)(value >> 24);
				Ram[(address & 0xFFFF) + 1] = (byte)(value >> 16);
				Ram[(address & 0xFFFF) + 2] = (byte)(value >> 8);
				Ram[(address & 0xFFFF) + 3] = (byte)value;
				return;
			}
			if (address >= 0xC00000)
			{
				WriteWord(address, (short)(value >> 16));
				WriteWord(address + 2, (short)value);
				return;
			}

			Console.WriteLine("UNHANDLED WRITEL {0:X6}:{1:X8}", address, value);
		}

		// Mushashi interop test stuff. TODO kill this when we're ready to ditch musashi.

		public uint Read8(uint a) { /*Console.WriteLine("read8 {0:X}", a);*/ return (uint)ReadByte((int)a) & 0xFF; }
		public uint Read16(uint a) { /*Console.WriteLine("read16 {0:X}", a);*/ return (uint)ReadWord((int)a) & 0xFFFF; }
		public uint Read32(uint a) { /*Console.WriteLine("read32 {0:X}", a);*/ return (uint)ReadLong((int)a); }
		public void Write8(uint a, uint v) { /*Console.WriteLine("write8 {0:X}:{1:X2}", a, v);*/ WriteByte((int)a, (sbyte)v); }
		public void Write16(uint a, uint v) { /*Console.WriteLine("write16 {0:X}:{1:X4}", a, v);*/ WriteWord((int)a, (short)v); }
		public void Write32(uint a, uint v) { /*Console.WriteLine("write32 {0:X}:{1:X8}", a, v);*/ WriteLong((int)a, (int)v); }
	}
}