using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using BizHawk.Emulation.CPUs.H6280;
using BizHawk.Emulation.Sound;
using BizHawk.DiscSystem;

namespace BizHawk.Emulation.Consoles.TurboGrafx
{
	public enum NecSystemType { TurboGrafx, TurboCD, SuperGrafx }

	[CoreVersion("1.2.1", FriendlyName = "TurboHawk16")]
	public sealed partial class PCEngine : IEmulator
	{
		// ROM
		public byte[] RomData;
		public int RomLength;
		Disc disc;

		// Machine
		public NecSystemType Type;
		public HuC6280 Cpu;
		public VDC VDC1, VDC2;
		public VCE VCE;
		public VPC VPC;
		public ScsiCDBus SCSI;
		public ADPCM ADPCM;

		public HuC6280PSG PSG;
		public CDAudio CDAudio;
		public SoundMixer SoundMixer;
		public MetaspuSoundProvider SoundSynchronizer;

		bool TurboGrafx { get { return Type == NecSystemType.TurboGrafx; } }
		bool SuperGrafx { get { return Type == NecSystemType.SuperGrafx; } }
		bool TurboCD { get { return Type == NecSystemType.TurboCD; } }

		// BRAM
		bool BramEnabled = false;
		bool BramLocked = true;
		byte[] BRAM;

		// Memory system
		public byte[] Ram;       // PCE= 8K base ram, SGX= 64k base ram
		public byte[] CDRam;     // TurboCD extra 64k of ram
		public byte[] SuperRam;  // Super System Card 192K of additional RAM
		public byte[] ArcadeRam; // Arcade Card 2048K of additional RAM

		private string systemid = "PCE";

		// 21,477,270  Machine clocks / sec
		//  7,159,090  Cpu cycles / sec

		public PCEngine(GameInfo game, byte[] rom)
		{
			CoreOutputComm = new CoreOutputComm();

			switch (game.System)
			{
				case "PCE":
					systemid = "PCE";
					Type = NecSystemType.TurboGrafx; 
					break;
				case "SGX":
					systemid = "SGX";
					Type = NecSystemType.SuperGrafx; 
					break;
			}
			Init(game, rom);
		}

		public PCEngine(GameInfo game, Disc disc, byte[] rom)
		{
			systemid = "PCECD";
			CoreOutputComm = new CoreOutputComm();
			Type = NecSystemType.TurboCD;
			this.disc = disc;
			Init(game, rom);
		}

		void Init(GameInfo game, byte[] rom)
		{
			Controller = NullController.GetNullController();
			Cpu = new HuC6280();
			VCE = new VCE();
			VDC1 = new VDC(this, Cpu, VCE);
			PSG = new HuC6280PSG();
			SCSI = new ScsiCDBus(this, disc);

			if (TurboGrafx)
			{
				Ram = new byte[0x2000];
				Cpu.ReadMemory21 = ReadMemory;
				Cpu.WriteMemory21 = WriteMemory;
				Cpu.WriteVDC = VDC1.WriteVDC;
				soundProvider = PSG;
				CDAudio = new CDAudio(null, 0);
			}

			else if (SuperGrafx)
			{
				VDC2 = new VDC(this, Cpu, VCE);
				VPC = new VPC(this, VDC1, VDC2, VCE, Cpu);
				Ram = new byte[0x8000];
				Cpu.ReadMemory21 = ReadMemorySGX;
				Cpu.WriteMemory21 = WriteMemorySGX;
				Cpu.WriteVDC = VDC1.WriteVDC;
				soundProvider = PSG;
				CDAudio = new CDAudio(null, 0);
			}

			else if (TurboCD)
			{
				Ram = new byte[0x2000];
				CDRam = new byte[0x10000];
				ADPCM = new ADPCM(this, SCSI);
				Cpu.ReadMemory21 = ReadMemoryCD;
				Cpu.WriteMemory21 = WriteMemoryCD;
				Cpu.WriteVDC = VDC1.WriteVDC;
				CDAudio = new CDAudio(disc);
				SetCDAudioCallback();
				PSG.MaxVolume = short.MaxValue * 3 / 4;
				SoundMixer = new SoundMixer(PSG, CDAudio, ADPCM);
				SoundSynchronizer = new MetaspuSoundProvider(ESynchMethod.ESynchMethod_V);
				soundProvider = SoundSynchronizer;
				Cpu.ThinkAction = (cycles) => { SCSI.Think(); ADPCM.Think(cycles); };
			}

			if (rom.Length == 0x60000)
			{
				// 384k roms require special loading code. Why ;_;
				// In memory, 384k roms look like [1st 256k][Then full 384k]
				RomData = new byte[0xA0000];
				var origRom = rom;
				for (int i = 0; i < 0x40000; i++)
					RomData[i] = origRom[i];
				for (int i = 0; i < 0x60000; i++)
					RomData[i + 0x40000] = origRom[i];
				RomLength = RomData.Length;
			}
			else if (rom.Length > 1024 * 1024)
			{
				// If the rom is bigger than 1 megabyte, switch to Street Fighter 2 mapper
				Cpu.ReadMemory21 = ReadMemorySF2;
				Cpu.WriteMemory21 = WriteMemorySF2;
				RomData = rom;
				RomLength = RomData.Length;
			}
			else
			{
				// normal rom.
				RomData = rom;
				RomLength = RomData.Length;
			}

			if (game["BRAM"] || Type == NecSystemType.TurboCD)
			{
				BramEnabled = true;
				BRAM = new byte[2048];

				// pre-format BRAM. damn are we helpful.
				BRAM[0] = 0x48; BRAM[1] = 0x55; BRAM[2] = 0x42; BRAM[3] = 0x4D;
				BRAM[4] = 0x00; BRAM[5] = 0x88; BRAM[6] = 0x10; BRAM[7] = 0x80;
			}

			if (game["SuperSysCard"])
				SuperRam = new byte[0x30000];

			if (game["ArcadeCard"])
			{
				ArcadeRam = new byte[0x200000];
				ArcadeCard = true;
				ArcadeCardRewindHack = game["ArcadeRewindHack"];
				for (int i = 0; i < 4; i++)
					ArcadePage[i] = new ArcadeCardPage();
			}

			if (game["PopulousSRAM"])
			{
				PopulousRAM = new byte[0x8000];
				Cpu.ReadMemory21 = ReadMemoryPopulous;
				Cpu.WriteMemory21 = WriteMemoryPopulous;
			}

			if (game["ForceSpriteLimit"] || game.NotInDatabase)
			{
				VDC1.PerformSpriteLimit = true;
				if (VDC2 != null)
					VDC2.PerformSpriteLimit = true;
			}

			if (game["CdVol"])
				CDAudio.MaxVolume = int.Parse(game.OptionValue("CdVol"));
			if (game["PsgVol"])
				PSG.MaxVolume = int.Parse(game.OptionValue("PsgVol"));
			if (game["AdpcmVol"])
				ADPCM.MaxVolume = int.Parse(game.OptionValue("AdpcmVol"));
			if (game["EqualizeVolumes"] || (game.NotInDatabase && TurboCD))
				SoundMixer.EqualizeVolumes();

			// Ok, yes, HBlankPeriod's only purpose is game-specific hax.
			// 1) At least they're not coded directly into the emulator, but instead data-driven.
			// 2) The games which have custom HBlankPeriods work without it, the override only
			//    serves to clean up minor gfx anomalies.
			// 3) There's no point in haxing the timing with incorrect values in an attempt to avoid this.
			//    The proper fix is cycle-accurate/bus-accurate timing. That isn't coming to the C# 
			//    version of this core. Let's just acknolwedge that the timing is imperfect and fix
			//    it in the least intrusive and most honest way we can.

			if (game["HBlankPeriod"])
				VDC1.HBlankCycles = int.Parse(game.OptionValue("HBlankPeriod"));

			// This is also a hack. Proper multi-res/TV emulation will be a native-code core feature.

			if (game["MultiResHack"])
			{
				VDC1.MultiResHack = int.Parse(game.OptionValue("MultiResHack"));
			}

			Cpu.ResetPC();
			SetupMemoryDomains();
		}

		int _lagcount = 0;
		bool lagged = true;
		bool islag = false;
		public int Frame { get; set; }
		public int LagCount { get { return _lagcount; } set { _lagcount = value; } }
		public bool IsLagFrame { get { return islag; } }

		public void ResetFrameCounter()
		{
			// this should just be a public setter instead of a new method.
			Frame = 0;
		}

		public void FrameAdvance(bool render)
		{
			lagged = true;
			Controller.UpdateControls(Frame++);

			PSG.BeginFrame(Cpu.TotalExecutedCycles);

			if (SuperGrafx)
				VPC.ExecFrame(render);
			else
				VDC1.ExecFrame(render);

			PSG.EndFrame(Cpu.TotalExecutedCycles);
			if (TurboCD)
				SoundSynchronizer.PullSamples(SoundMixer);

			if (lagged)
			{
				_lagcount++;
				islag = true;
			}
			else
				islag = false;
		}

		public CoreInputComm CoreInputComm { get; set; }
		public CoreOutputComm CoreOutputComm { get; private set; }

		public IVideoProvider VideoProvider
		{
			get { return (IVideoProvider)VPC ?? VDC1; }
		}

		ISoundProvider soundProvider;
		public ISoundProvider SoundProvider
		{
			get { return soundProvider; }
		}

		public string SystemId { get { return systemid; } }
		public string Region { get; set; }
		public bool DeterministicEmulation { get; set; }

		public byte[] SaveRam
		{
			get { return BRAM; }
		}

		public bool SaveRamModified { get; set; }

		public void SaveStateText(TextWriter writer)
		{
			writer.WriteLine("[PCEngine]");
			writer.Write("RAM ");
			Ram.SaveAsHex(writer);
			if (PopulousRAM != null)
			{
				writer.Write("PopulousRAM ");
				PopulousRAM.SaveAsHex(writer);
			}
			writer.WriteLine("Frame {0}", Frame);
			writer.WriteLine("Lag {0}", _lagcount);
			if (Cpu.ReadMemory21 == ReadMemorySF2)
				writer.WriteLine("SF2MapperLatch " + SF2MapperLatch);
			writer.WriteLine("IOBuffer {0:X2}", IOBuffer);
			writer.Write("CdIoPorts "); CdIoPorts.SaveAsHex(writer);
			writer.WriteLine();

			if (SuperGrafx)
			{
				Cpu.SaveStateText(writer);
				VPC.SaveStateText(writer);
				VCE.SaveStateText(writer);
				VDC1.SaveStateText(writer, 1);
				VDC2.SaveStateText(writer, 2);
				PSG.SaveStateText(writer);
			}
			else
			{
				Cpu.SaveStateText(writer);
				VCE.SaveStateText(writer);
				VDC1.SaveStateText(writer, 1);
				PSG.SaveStateText(writer);
			}
			if (TurboCD)
			{
				writer.Write("CDRAM "); CDRam.SaveAsHex(writer);
				if (SuperRam != null)
				{ writer.Write("SuperRAM "); SuperRam.SaveAsHex(writer); }

				writer.WriteLine();
				SCSI.SaveStateText(writer);
				CDAudio.SaveStateText(writer);
				ADPCM.SaveStateText(writer);
			}
			if (ArcadeCard)
				SaveArcadeCardText(writer);

			writer.WriteLine("[/PCEngine]");
		}

		public void LoadStateText(TextReader reader)
		{
			while (true)
			{
				string[] args = reader.ReadLine().Split(' ');
				if (args[0].Trim() == "") continue;
				if (args[0] == "[PCEngine]") continue;
				if (args[0] == "[/PCEngine]") break;
				if (args[0] == "Frame")
					Frame = int.Parse(args[1]);
				else if (args[0] == "Lag")
					_lagcount = int.Parse(args[1]);
				else if (args[0] == "SF2MapperLatch")
					SF2MapperLatch = byte.Parse(args[1]);
				else if (args[0] == "IOBuffer")
					IOBuffer = byte.Parse(args[1], NumberStyles.HexNumber);
				else if (args[0] == "CdIoPorts")
					CdIoPorts.ReadFromHex(args[1]);
				else if (args[0] == "RAM")
					Ram.ReadFromHex(args[1]);
				else if (args[0] == "CDRAM")
					CDRam.ReadFromHex(args[1]);
				else if (args[0] == "SuperRAM")
					SuperRam.ReadFromHex(args[1]);
				else if (args[0] == "PopulousRAM" && PopulousRAM != null)
					PopulousRAM.ReadFromHex(args[1]);
				else if (args[0] == "[HuC6280]")
					Cpu.LoadStateText(reader);
				else if (args[0] == "[PSG]")
					PSG.LoadStateText(reader);
				else if (args[0] == "[VCE]")
					VCE.LoadStateText(reader);
				else if (args[0] == "[VPC]")
					VPC.LoadStateText(reader);
				else if (args[0] == "[VDC1]")
					VDC1.LoadStateText(reader, 1);
				else if (args[0] == "[VDC2]")
					VDC2.LoadStateText(reader, 2);
				else if (args[0] == "[SCSI]")
					SCSI.LoadStateText(reader);
				else if (args[0] == "[CDAudio]")
					CDAudio.LoadStateText(reader);
				else if (args[0] == "[ADPCM]")
					ADPCM.LoadStateText(reader);
				else if (args[0] == "[ArcadeCard]")
					LoadArcadeCardText(reader);
				else
					Console.WriteLine("Skipping unrecognized identifier " + args[0]);
			}
		}

		public void SaveStateBinary(BinaryWriter writer)
		{
			if (SuperGrafx == false)
			{
				writer.Write(Ram);
				writer.Write(CdIoPorts);
				RefreshIRQ2();
				if (BRAM != null)
					writer.Write(BRAM);
				if (PopulousRAM != null)
					writer.Write(PopulousRAM);
				if (SuperRam != null)
					writer.Write(SuperRam);
				if (TurboCD)
				{
					writer.Write(CDRam);
					ADPCM.SaveStateBinary(writer);
					CDAudio.SaveStateBinary(writer);
					SCSI.SaveStateBinary(writer);
				}
				if (ArcadeCard)
					SaveArcadeCardBinary(writer);
				writer.Write(Frame);
				writer.Write(_lagcount);
				writer.Write(SF2MapperLatch);
				writer.Write(IOBuffer);
				Cpu.SaveStateBinary(writer);
				VCE.SaveStateBinary(writer);
				VDC1.SaveStateBinary(writer);
				PSG.SaveStateBinary(writer);
			}
			else
			{
				writer.Write(Ram);
				writer.Write(Frame);
				writer.Write(_lagcount);
				writer.Write(IOBuffer);
				Cpu.SaveStateBinary(writer);
				VCE.SaveStateBinary(writer);
				VPC.SaveStateBinary(writer);
				VDC1.SaveStateBinary(writer);
				VDC2.SaveStateBinary(writer);
				PSG.SaveStateBinary(writer);
			}
		}

		public void LoadStateBinary(BinaryReader reader)
		{
			if (SuperGrafx == false)
			{
				Ram = reader.ReadBytes(0x2000);
				CdIoPorts = reader.ReadBytes(16);
				if (BRAM != null)
					BRAM = reader.ReadBytes(0x800);
				if (PopulousRAM != null)
					PopulousRAM = reader.ReadBytes(0x8000);
				if (SuperRam != null)
					SuperRam = reader.ReadBytes(0x30000);
				if (TurboCD)
				{
					CDRam = reader.ReadBytes(0x10000);
					ADPCM.LoadStateBinary(reader);
					CDAudio.LoadStateBinary(reader);
					SCSI.LoadStateBinary(reader);
				}
				if (ArcadeCard)
					LoadArcadeCardBinary(reader);
				Frame = reader.ReadInt32();
				_lagcount = reader.ReadInt32();
				SF2MapperLatch = reader.ReadByte();
				IOBuffer = reader.ReadByte();
				Cpu.LoadStateBinary(reader);
				VCE.LoadStateBinary(reader);
				VDC1.LoadStateBinary(reader);
				PSG.LoadStateBinary(reader);
			}
			else
			{
				Ram = reader.ReadBytes(0x8000);
				Frame = reader.ReadInt32();
				_lagcount = reader.ReadInt32();
				IOBuffer = reader.ReadByte();
				Cpu.LoadStateBinary(reader);
				VCE.LoadStateBinary(reader);
				VPC.LoadStateBinary(reader);
				VDC1.LoadStateBinary(reader);
				VDC2.LoadStateBinary(reader);
				PSG.LoadStateBinary(reader);
			}
		}

		public byte[] SaveStateBinary()
		{
			int buflen = 75887;
			if (SuperGrafx) buflen += 90698;
			if (BramEnabled) buflen += 2048;
			if (PopulousRAM != null) buflen += 0x8000;
			if (SuperRam != null) buflen += 0x30000;
			if (TurboCD) buflen += 0x20000 + 2165;
			if (ArcadeCard) buflen += 42;
			if (ArcadeCard && !ArcadeCardRewindHack) buflen += 0x200000;
			//Console.WriteLine("LENGTH1 " + buflen);

			var buf = new byte[buflen];
			var stream = new MemoryStream(buf);
			var writer = new BinaryWriter(stream);
			SaveStateBinary(writer);
			//Console.WriteLine("LENGTH2 " + stream.Position);
			writer.Close();
			return buf;
		}

		void SetupMemoryDomains()
		{
			var domains = new List<MemoryDomain>(10);
			var MainMemoryDomain = new MemoryDomain("Main Memory", Ram.Length, Endian.Little,
				addr => Ram[addr & 0x1FFF],
				(addr, value) => Ram[addr & 0x1FFF] = value);
			domains.Add(MainMemoryDomain);

			var SystemBusDomain = new MemoryDomain("System Bus", 0x200000, Endian.Little,
				addr => Cpu.ReadMemory21(addr),
				(addr, value) => Cpu.WriteMemory21(addr, value));
			domains.Add(SystemBusDomain);

			if (BRAM != null)
			{
				var BRAMMemoryDomain = new MemoryDomain("Battery RAM", Ram.Length, Endian.Little,
					addr => BRAM[addr & 0x7FF],
					(addr, value) => BRAM[addr & 0x7FF] = value);
				domains.Add(BRAMMemoryDomain);
			}

			if (TurboCD)
			{
				var CDRamMemoryDomain = new MemoryDomain("TurboCD RAM", CDRam.Length, Endian.Little,
					addr => CDRam[addr & 0xFFFF],
					(addr, value) => CDRam[addr & 0xFFFF] = value);
				domains.Add(CDRamMemoryDomain);

				var AdpcmMemoryDomain = new MemoryDomain("ADPCM RAM", ADPCM.RAM.Length, Endian.Little,
					addr => ADPCM.RAM[addr & 0xFFFF],
					(addr, value) => ADPCM.RAM[addr & 0xFFFF] = value);
				domains.Add(AdpcmMemoryDomain);

				if (SuperRam != null)
				{
					var SuperRamMemoryDomain = new MemoryDomain("Super System Card RAM", SuperRam.Length, Endian.Little,
						addr => SuperRam[addr & 0x3FFFF],
						(addr, value) => SuperRam[addr & 0x3FFFF] = value);
					domains.Add(SuperRamMemoryDomain);
				}
			}

			if (ArcadeCard)
			{
				var ArcadeRamMemoryDomain = new MemoryDomain("Aracde Card RAM", ArcadeRam.Length, Endian.Little,
						addr => ArcadeRam[addr & 0x1FFFFF],
						(addr, value) => ArcadeRam[addr & 0x1FFFFF] = value);
				domains.Add(ArcadeRamMemoryDomain);
			}

			memoryDomains = domains.AsReadOnly();
		}

		IList<MemoryDomain> memoryDomains;
		public IList<MemoryDomain> MemoryDomains { get { return memoryDomains; } }
		public MemoryDomain MainMemory { get { return memoryDomains[0]; } }

		public void Dispose()
		{
			if (disc != null)
				disc.Dispose();
		}
	}
}