/*
 * Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 *
 * (c) Copyright 1996 - 2001 Gary Henderson (gary.henderson@ntlworld.com) and
 *                           Jerremy Koot (jkoot@snes9x.com)
 *
 * Super FX C emulator code 
 * (c) Copyright 1997 - 1999 Ivar (ivar@snes9x.com) and
 *                           Gary Henderson.
 * Super FX assembler emulator code (c) Copyright 1998 zsKnight and _Demo_.
 *
 * DSP1 emulator code (c) Copyright 1998 Ivar, _Demo_ and Gary Henderson.
 * C4 asm and some C emulation code (c) Copyright 2000 zsKnight and _Demo_.
 * C4 C code (c) Copyright 2001 Gary Henderson (gary.henderson@ntlworld.com).
 *
 * DOS port code contains the works of other authors. See headers in
 * individual files.
 *
 * Snes9x homepage: http://www.snes9x.com
 *
 * Permission to use, copy, modify and distribute Snes9x in both binary and
 * source form, for non-commercial purposes, is hereby granted without fee,
 * providing that this license information and copyright notice appear with
 * all copies and any derived work.
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event shall the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Snes9x is freeware for PERSONAL USE only. Commercial users should
 * seek permission of the copyright holders first. Commercial use includes
 * charging money for Snes9x or software derived from Snes9x.
 *
 * The copyright holders request that bug fixes and improvements to the code
 * should be forwarded to them so everyone can benefit from the modifications
 * in future versions.
 *
 * Super NES and Super Nintendo Entertainment System are trademarks of
 * Nintendo Co., Limited and its subsidiary companies.
 */
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

#if defined(__unix) || defined(__linux) || defined(__sun) || defined(__DJGPP)
//#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#endif

#include "snapshot.h"
#include "snaporig.h"
#include "memmap.h"
#include "snes9x.h"
#include "65c816.h"
#include "ppu.h"
#include "cpuexec.h"
#include "display.h"
#include "apu.h"
#include "soundux.h"

struct SOrigPPU OrigPPU;
struct SOrigDMA OrigDMA [8];
struct SOrigRegisters OrigRegisters;
struct SOrigCPUState OrigCPU;
struct SOrigAPU OrigAPU;
SOrigSoundData OrigSoundData;
struct SOrigAPURegisters OrigAPURegisters;
char ROMFilename [1025];

static int ReadOrigSnapshot (STREAM);

bool8_32 S9xLoadOrigSnapshot (const char *filename)
{
    STREAM snapshot = NULL;
    if (S9xOpenSnapshotFile (filename, TRUE, &snapshot))
    {
	int result;
	if ((result = ReadOrigSnapshot (snapshot)) != SUCCESS)
	{
	    S9xCloseSnapshotFile (snapshot);
	    return (FALSE);
	}
	S9xCloseSnapshotFile (snapshot);
	return (TRUE);
    }
    return (FALSE);
}

static int ReadBlock (const char *key, void *block, int max_len, STREAM snap)
{
    char buffer [20];
    int len = 0;
    int rem = 0;
    
    if (READ_STREAM (buffer, 11, snap) != 11 ||
	strncmp (buffer, key, 4) != 0 ||
	(len = atoi (&buffer [4])) == 0)
	return (WRONG_FORMAT);

    if (len > max_len)
    {
	rem = len - max_len;
	len = max_len;
    }
    if (READ_STREAM (block, len, snap) != len)
	return (WRONG_FORMAT);

    if (rem)
    {
	char *junk = new char [rem];
	READ_STREAM (junk, rem, snap);
	delete junk;
    }
	
    return (SUCCESS);
}

static int ReadOrigSnapshot (STREAM snap)
{
    char buffer [_MAX_PATH];
    char rom_filename [_MAX_PATH];
    int result;
    int i;
    int j;

    int version;
    int len = strlen (ORIG_SNAPSHOT_MAGIC) + 1 + 4 + 1;
    if (READ_STREAM (buffer, len, snap) != len)
	return (WRONG_FORMAT);
    if (strncmp (buffer, ORIG_SNAPSHOT_MAGIC, strlen (ORIG_SNAPSHOT_MAGIC)) != 0)
	return (WRONG_FORMAT);
    if ((version = atoi (&buffer [strlen (SNAPSHOT_MAGIC) + 1])) > ORIG_SNAPSHOT_VERSION)
	return (WRONG_VERSION);

    if ((result = ReadBlock ("NAM:", rom_filename, _MAX_PATH, snap)) != SUCCESS)
	return (result);

    if ((result = ReadBlock ("HiR:", buffer, 0x41, snap)) != SUCCESS)
	return (result);

    if (strcasecmp (rom_filename, Memory.ROMFilename) != 0 &&
	strcasecmp (S9xBasename (rom_filename), S9xBasename (Memory.ROMFilename)) != 0)
    {
	S9xMessage (S9X_WARNING, S9X_FREEZE_ROM_NAME,
		    "Current loaded ROM image doesn't match that required by freeze-game file.");
    }

    S9xReset ();
    S9xSetSoundMute (TRUE);
    if ((result = ReadBlock ("CPU:", &OrigCPU, sizeof (OrigCPU), snap)) != SUCCESS)
	return (result);
    OrigCPU.FastROMSpeed = OrigCPU.FastROMSpeed_old;
    Memory.FixROMSpeed ();
    if (version == 3)
    {
	OrigCPU.Cycles = OrigCPU.Cycles_old;
	OrigCPU.NextEvent = OrigCPU.NextEvent_old;
	OrigCPU.V_Counter = OrigCPU.V_Counter_old;
	OrigCPU.MemSpeed = OrigCPU.MemSpeed_old;
	OrigCPU.MemSpeedx2 = OrigCPU.MemSpeedx2_old;
	OrigCPU.FastROMSpeed = OrigCPU.FastROMSpeed_old;
    }
    CPU.Flags = OrigCPU.Flags;
    CPU.BranchSkip = OrigCPU.BranchSkip;
    CPU.NMIActive = OrigCPU.NMIActive;
    CPU.IRQActive = OrigCPU.IRQActive;
    CPU.WaitingForInterrupt = OrigCPU.WaitingForInterrupt;
    CPU.WhichEvent = OrigCPU.WhichEvent;
    CPU.Cycles = OrigCPU.Cycles;
    CPU.NextEvent = OrigCPU.NextEvent;
    CPU.V_Counter = OrigCPU.V_Counter;
    CPU.MemSpeed = OrigCPU.MemSpeed;
    CPU.MemSpeedx2 = OrigCPU.MemSpeedx2;
    CPU.FastROMSpeed = OrigCPU.FastROMSpeed;

    if ((result = ReadBlock ("REG:", &OrigRegisters, sizeof (OrigRegisters), snap)) != SUCCESS)
	return (result);

    Registers = *(struct SRegisters *) &OrigRegisters;

    if ((result = ReadBlock ("PPU:", &OrigPPU, sizeof (OrigPPU), snap)) != SUCCESS)
	return (result);

    if (version == 2)
    {
	OrigPPU.OBJNameSelect = OrigPPU.OBJNameSelect_old << 13;
	OrigPPU.OBJNameBase <<= 1;
	OrigPPU.OBJNameSelect <<= 13;
    }
    PPU.BGMode = OrigPPU.BGMode;
    PPU.BG3Priority = OrigPPU.BG3Priority;
    PPU.Brightness = OrigPPU.Brightness;

    PPU.VMA.High = OrigPPU.VMA.High;
    PPU.VMA.Increment = OrigPPU.VMA.Increment;
    PPU.VMA.Address = OrigPPU.VMA.Address;
    PPU.VMA.Mask1 = OrigPPU.VMA.Mask1;
    PPU.VMA.FullGraphicCount = OrigPPU.VMA.FullGraphicCount;
    PPU.VMA.Shift = OrigPPU.VMA.Shift;

    for (i = 0; i < 4; i++)
    {
	PPU.BG[i].SCBase = OrigPPU.BG[i].SCBase;
	PPU.BG[i].VOffset = OrigPPU.BG[i].VOffset;
	PPU.BG[i].HOffset = OrigPPU.BG[i].HOffset;
	PPU.BG[i].BGSize = OrigPPU.BG[i].BGSize;
	PPU.BG[i].NameBase = OrigPPU.BG[i].NameBase;
	PPU.BG[i].SCSize = OrigPPU.BG[i].SCSize;
    }

    PPU.CGFLIP = OrigPPU.CGFLIP;
    for (i = 0; i < 256; i++)
	PPU.CGDATA [i] = OrigPPU.CGDATA [i];
    PPU.FirstSprite = OrigPPU.FirstSprite;
    for (i = 0; i < 128; i++)
    {
	PPU.OBJ[i].HPos = OrigPPU.OBJ [i].HPos;
	PPU.OBJ[i].VPos = OrigPPU.OBJ [i].VPos;
	PPU.OBJ[i].Name = OrigPPU.OBJ [i].Name;
	PPU.OBJ[i].VFlip = OrigPPU.OBJ [i].VFlip;
	PPU.OBJ[i].HFlip = OrigPPU.OBJ [i].HFlip;
	PPU.OBJ[i].Priority = OrigPPU.OBJ [i].Priority;
	PPU.OBJ[i].Palette = OrigPPU.OBJ [i].Palette;
	PPU.OBJ[i].Size = OrigPPU.OBJ [i].Size;
    }
    PPU.OAMPriorityRotation = OrigPPU.OAMPriorityRotation;
    PPU.OAMAddr = OrigPPU.OAMAddr;

    PPU.OAMFlip = OrigPPU.OAMFlip;
    PPU.OAMTileAddress = OrigPPU.OAMTileAddress;
    PPU.IRQVBeamPos = OrigPPU.IRQVBeamPos;
    PPU.IRQHBeamPos = OrigPPU.IRQHBeamPos;
    PPU.VBeamPosLatched = OrigPPU.VBeamPosLatched;
    PPU.HBeamPosLatched = OrigPPU.HBeamPosLatched;

    PPU.HBeamFlip = OrigPPU.HBeamFlip;
    PPU.VBeamFlip = OrigPPU.VBeamFlip;
    PPU.HVBeamCounterLatched = OrigPPU.HVBeamCounterLatched;

    PPU.MatrixA = OrigPPU.MatrixA;
    PPU.MatrixB = OrigPPU.MatrixB;
    PPU.MatrixC = OrigPPU.MatrixC;
    PPU.MatrixD = OrigPPU.MatrixD;
    PPU.CentreX = OrigPPU.CentreX;
    PPU.CentreY = OrigPPU.CentreY;
    PPU.Joypad1ButtonReadPos = OrigPPU.Joypad1ButtonReadPos;
    PPU.Joypad2ButtonReadPos = OrigPPU.Joypad2ButtonReadPos;
    PPU.Joypad3ButtonReadPos = OrigPPU.Joypad3ButtonReadPos;

    PPU.CGADD = OrigPPU.CGADD;
    PPU.FixedColourRed = OrigPPU.FixedColourRed;
    PPU.FixedColourGreen = OrigPPU.FixedColourGreen;
    PPU.FixedColourBlue = OrigPPU.FixedColourBlue;
    PPU.SavedOAMAddr = OrigPPU.SavedOAMAddr;
    PPU.ScreenHeight = OrigPPU.ScreenHeight;
    PPU.WRAM = OrigPPU.WRAM;
    PPU.ForcedBlanking = OrigPPU.ForcedBlanking;
    PPU.OBJNameSelect = OrigPPU.OBJNameSelect;
    PPU.OBJSizeSelect = OrigPPU.OBJSizeSelect;
    PPU.OBJNameBase = OrigPPU.OBJNameBase;
    PPU.OAMReadFlip = OrigPPU.OAMReadFlip;
    memmove (PPU.OAMData, OrigPPU.OAMData, sizeof (PPU.OAMData));
    PPU.VTimerEnabled = OrigPPU.VTimerEnabled;
    PPU.HTimerEnabled = OrigPPU.HTimerEnabled;
    PPU.HTimerPosition = OrigPPU.HTimerPosition;
    PPU.Mosaic = OrigPPU.Mosaic;
    memmove (PPU.BGMosaic, OrigPPU.BGMosaic, sizeof (PPU.BGMosaic));
    PPU.Mode7HFlip = OrigPPU.Mode7HFlip;
    PPU.Mode7VFlip = OrigPPU.Mode7VFlip;
    PPU.Mode7Repeat = OrigPPU.Mode7Repeat;
    PPU.Window1Left = OrigPPU.Window1Left;
    PPU.Window1Right = OrigPPU.Window1Right;
    PPU.Window2Left = OrigPPU.Window2Left;
    PPU.Window2Right = OrigPPU.Window2Right;
    for (i = 0; i < 6; i++)
    {
	PPU.ClipWindowOverlapLogic [i] = OrigPPU.ClipWindowOverlapLogic [i];
	PPU.ClipWindow1Enable [i] = OrigPPU.ClipWindow1Enable [i];
	PPU.ClipWindow2Enable [i] = OrigPPU.ClipWindow2Enable [i];
	PPU.ClipWindow1Inside [i] = OrigPPU.ClipWindow1Inside [i];
	PPU.ClipWindow2Inside [i] = OrigPPU.ClipWindow2Inside [i];
    }
    PPU.CGFLIPRead = OrigPPU.CGFLIPRead;
    PPU.Need16x8Mulitply = OrigPPU.Need16x8Mulitply;

    IPPU.ColorsChanged = TRUE;
    IPPU.OBJChanged = TRUE;
    S9xFixColourBrightness ();
    IPPU.RenderThisFrame = FALSE;

    if ((result = ReadBlock ("DMA:", OrigDMA, sizeof (OrigDMA), snap)) != SUCCESS)
	return (result);

    for (i = 0; i < 8; i++)
    {
	DMA[i].TransferDirection = OrigDMA[i].TransferDirection;
	DMA[i].AAddressFixed = OrigDMA[i].AAddressFixed;
	DMA[i].AAddressDecrement = OrigDMA[i].AAddressDecrement;
	DMA[i].TransferMode = OrigDMA[i].TransferMode;
	DMA[i].ABank = OrigDMA[i].ABank;
	DMA[i].AAddress = OrigDMA[i].AAddress;
	DMA[i].Address = OrigDMA[i].Address;
	DMA[i].BAddress = OrigDMA[i].BAddress;
	DMA[i].TransferBytes = OrigDMA[i].TransferBytes;
	DMA[i].HDMAIndirectAddressing = OrigDMA[i].HDMAIndirectAddressing;
	DMA[i].IndirectAddress = OrigDMA[i].IndirectAddress;
	DMA[i].IndirectBank = OrigDMA[i].IndirectBank;
	DMA[i].Repeat = OrigDMA[i].Repeat;
	DMA[i].LineCount = OrigDMA[i].LineCount;
	DMA[i].FirstLine = OrigDMA[i].FirstLine;
    }

    if ((result = ReadBlock ("VRA:", Memory.VRAM, 0x10000, snap)) != SUCCESS)
	return (result);
    if ((result = ReadBlock ("RAM:", Memory.RAM, 0x20000, snap)) != SUCCESS)
	return (result);
    if ((result = ReadBlock ("SRA:", SRAM, 0x10000, snap)) != SUCCESS)
	return (result);
    if ((result = ReadBlock ("FIL:", Memory.FillRAM, 0x8000, snap)) != SUCCESS)
	return (result);
    if (ReadBlock ("APU:", &OrigAPU, sizeof (OrigAPU), snap) == SUCCESS)
    {
	APU = *(struct SAPU *) &OrigAPU;

	if ((result = ReadBlock ("ARE:", &OrigAPURegisters,
				 sizeof (OrigAPURegisters), snap)) != SUCCESS)
	    return (result);
	APURegisters = *(struct SAPURegisters *) &OrigAPURegisters;
	if ((result = ReadBlock ("ARA:", IAPU.RAM, 0x10000, snap)) != SUCCESS)
	    return (result);
	if ((result = ReadBlock ("SOU:", &OrigSoundData,
				 sizeof (SOrigSoundData), snap)) != SUCCESS)
	    return (result);

	SoundData.master_volume_left = OrigSoundData.master_volume_left;
	SoundData.master_volume_right = OrigSoundData.master_volume_right;
	SoundData.echo_volume_left = OrigSoundData.echo_volume_left;
	SoundData.echo_volume_right = OrigSoundData.echo_volume_right; 
	SoundData.echo_enable = OrigSoundData.echo_enable;
	SoundData.echo_feedback = OrigSoundData.echo_feedback;
	SoundData.echo_ptr = OrigSoundData.echo_ptr;
	SoundData.echo_buffer_size = OrigSoundData.echo_buffer_size;
	SoundData.echo_write_enabled = OrigSoundData.echo_write_enabled;
	SoundData.echo_channel_enable = OrigSoundData.echo_channel_enable;
	SoundData.pitch_mod = OrigSoundData.pitch_mod;

	for (i = 0; i < 3; i++)
	    SoundData.dummy [i] = OrigSoundData.dummy [i];
	for (i = 0; i < NUM_CHANNELS; i++)
	{
	    SoundData.channels [i].state = OrigSoundData.channels [i].state;
	    SoundData.channels [i].type = OrigSoundData.channels [i].type;
	    SoundData.channels [i].volume_left = OrigSoundData.channels [i].volume_left;
	    SoundData.channels [i].volume_right = OrigSoundData.channels [i].volume_right;
	    SoundData.channels [i].hertz = OrigSoundData.channels [i].frequency;
	    SoundData.channels [i].count = OrigSoundData.channels [i].count;
	    SoundData.channels [i].loop = OrigSoundData.channels [i].loop;
	    SoundData.channels [i].envx = OrigSoundData.channels [i].envx;
	    SoundData.channels [i].left_vol_level = OrigSoundData.channels [i].left_vol_level;
	    SoundData.channels [i].right_vol_level = OrigSoundData.channels [i].right_vol_level;
	    SoundData.channels [i].envx_target = OrigSoundData.channels [i].envx_target;
	    SoundData.channels [i].env_error = OrigSoundData.channels [i].env_error;
	    SoundData.channels [i].erate = OrigSoundData.channels [i].erate;
	    SoundData.channels [i].direction = OrigSoundData.channels [i].direction;
	    SoundData.channels [i].attack_rate = OrigSoundData.channels [i].attack_rate;
	    SoundData.channels [i].decay_rate = OrigSoundData.channels [i].decay_rate;
	    SoundData.channels [i].sustain_rate = OrigSoundData.channels [i].sustain_rate;
	    SoundData.channels [i].release_rate = OrigSoundData.channels [i].release_rate;
	    SoundData.channels [i].sustain_level = OrigSoundData.channels [i].sustain_level;
	    SoundData.channels [i].sample = OrigSoundData.channels [i].sample;
	    for (j = 0; j < 16; j++)
		SoundData.channels [i].decoded [j] = OrigSoundData.channels [i].decoded [j];

	    for (j = 0; j < 2; j++)
		SoundData.channels [i].previous [j] = OrigSoundData.channels [i].previous [j];

	    SoundData.channels [i].sample_number = OrigSoundData.channels [i].sample_number;
	    SoundData.channels [i].last_block = OrigSoundData.channels [i].last_block;
	    SoundData.channels [i].needs_decode = OrigSoundData.channels [i].needs_decode;
	    SoundData.channels [i].block_pointer = OrigSoundData.channels [i].block_pointer;
	    SoundData.channels [i].sample_pointer = OrigSoundData.channels [i].sample_pointer;
	    SoundData.channels [i].mode = OrigSoundData.channels [i].mode;
	}

	S9xSetSoundMute (FALSE);
	IAPU.PC = IAPU.RAM + IAPU.PC;
	S9xAPUUnpackStatus ();
	if (APUCheckDirectPage ())
	    IAPU.DirectPage = IAPU.RAM + 0x100;
	else
	    IAPU.DirectPage = IAPU.RAM;
	Settings.APUEnabled = TRUE;
	CPU.APU_APUExecuting = TRUE;
    }
    else
    {
	Settings.APUEnabled = FALSE;
	CPU.APU_APUExecuting = FALSE;
	S9xSetSoundMute (TRUE);
    }
    S9xFixSoundAfterSnapshotLoad ();
    ICPU.ShiftedPB = Registers.PB << 16;
    ICPU.ShiftedDB = Registers.DB << 16;
    S9xSetPCBase (ICPU.ShiftedPB + Registers.PC, &CPU);
    S9xUnpackStatus ();
    S9xFixCycles (&Registers, &ICPU);
    S9xReschedule ();

    return (SUCCESS);
}