/*
 * Snake_Save  Copyright (c) 1988  MKSoft
 *
 * These routines set up and save the program's data in either a data file
 * or within the code itself...
 */

#include	"Snake.h"
#include	"Snake_Save.h"

#define	BUFF_SIZE	512L

static	struct	FileHandle	*fd=NULL;

static		long		Keys_Pos=NULL;
static		long		Score_Pos=NULL;
static		long		Screen_Pos=NULL;

static		char		FileID[]=FILE_ID_HEADER;

static		char		Buffer[BUFF_SIZE];

static	long	Find_Pos(data,size)	register	char	*data;
							long	size;
{
register	long	pos=NULL;
register	long	rds;
register	long	p;
register	long	t;
		long	tfound;
		long	found=NULL;
		short	flag=TRUE;
		short	flag1;
		short	flag2;

	while (flag)
	{
		Seek(fd,pos,OFFSET_BEGINNING);
		rds=Read(fd,Buffer,BUFF_SIZE);
		flag2=TRUE;
		if (rds)
		{
			p=NULL;
			while ((p<rds)&&flag2)
			{
				t=NULL;
				if (Buffer[p]==data[t])
				{
					tfound=pos+p;
					flag1=TRUE;
					while (flag1)
					{
						t++;
						if (t<size)
						{
							p++;
							if (p>=rds)
							{
								rds=Read(fd,Buffer,BUFF_SIZE);
								p=NULL;
								flag2=FALSE;
								pos=tfound+1L;
							}
							if (p<rds)
							{
								if (Buffer[p]!=data[t]) flag1=FALSE;
							}
							else flag1=FALSE;
						}
						else
						{
							flag2=flag1=flag=FALSE;
							found=tfound;
						}
					}
				}
				else p++;
			}
		}
		else flag=FALSE;
	}
	return(found);
}

VOID	SetUp_For_Save()
{
char	temp[sizeof(FileID)];

	if (fd=Open(Save_File,MODE_OLDFILE))
	{
		Seek(fd,0L,OFFSET_BEGINNING);
		Read(fd,temp,(long)sizeof(FileID));
		if (strcmp(temp,FileID))
		{	/* The exec file... */
			Keys_Pos=Find_Pos(KeyList,(long)sizeof(KeyList));
			Score_Pos=Find_Pos(ScoreList,(long)sizeof(ScoreList));
			Screen_Pos=Find_Pos(All_Pit_Screens[0],(long)sizeof(Pit_Screen));
		}
		else
		{	/* A data file... */
			Score_Pos=Seek(fd,0L,OFFSET_CURRENT);
			Read(fd,ScoreList,(long)sizeof(ScoreList));
			Keys_Pos=Seek(fd,0L,OFFSET_CURRENT);
			Read(fd,KeyList,(long)sizeof(KeyList));
			Screen_Pos=Seek(fd,0L,OFFSET_CURRENT);
			Read(fd,All_Pit_Screens[0],(long)(((long)MAX_LEVEL)*((long)sizeof(Pit_Screen))));
		}
	}
	else if (fd=Open(Save_File,MODE_NEWFILE))
	{	/* A new data file... */
		Seek(fd,0L,OFFSET_BEGINNING);
		Write(fd,FileID,(long)sizeof(FileID));
		Score_Pos=Seek(fd,0L,OFFSET_CURRENT);
		Write(fd,ScoreList,(long)sizeof(ScoreList));
		Keys_Pos=Seek(fd,0L,OFFSET_CURRENT);
		Write(fd,KeyList,(long)sizeof(KeyList));
		Screen_Pos=Seek(fd,0L,OFFSET_CURRENT);
		Write(fd,All_Pit_Screens[0],(long)(((long)MAX_LEVEL)*((long)sizeof(Pit_Screen))));
	}
	if (fd) Close(fd);
}

VOID	Save_It_Now(Screens,Scores,Keys)	short	Screens;
						short	Scores;
						short	Keys;
{
	if ((Score_Pos)&&(Keys_Pos)&&(Screen_Pos)&&((Screens)||(Scores)||(Keys)))
		if (fd=Open(Save_File,MODE_OLDFILE))
		{
			if (Keys)
			{
				Seek(fd,Keys_Pos,OFFSET_BEGINNING);
				Write(fd,KeyList,(long)sizeof(KeyList));
			}
			if (Scores)
			{
				Seek(fd,Score_Pos,OFFSET_BEGINNING);
				Write(fd,ScoreList,(long)sizeof(ScoreList));
			}
			if (Screens)
			{
				Seek(fd,Screen_Pos,OFFSET_BEGINNING);
				Write(fd,All_Pit_Screens[0],(long)(((long)MAX_LEVEL)*((long)sizeof(Pit_Screen))));
			}
			Close(fd);
		}
}