/***
*
*	Copyright (c) 1998, Valve LLC. All rights reserved.
*	
*	This product contains software technology licensed from Id 
*	Software, Inc. ("Id Technology").  Id Technology (c) 1996 Id Software, Inc. 
*	All Rights Reserved.
*
****/

// scriplib.c

#include "cmdlib.h"
#include "scriplib.h"

/*
=============================================================================

						PARSING STUFF

=============================================================================
*/

typedef struct
{
	char	filename[1024];
	char    *buffer,*script_p,*end_p;
	int     line;
} script_t;

#define	MAX_INCLUDES	8
script_t	scriptstack[MAX_INCLUDES];
script_t	*script;
int			scriptline;

char    token[MAXTOKEN];
qboolean endofscript;
qboolean tokenready;                     // only true if UnGetToken was just called

/*
==============
AddScriptToStack
==============
*/
void AddScriptToStack (char *filename)
{
	int            size;

	script++;
	if (script == &scriptstack[MAX_INCLUDES])
		Error ("script file exceeded MAX_INCLUDES");
	strcpy (script->filename, ExpandPath (filename) );

	size = LoadFile (script->filename, (void **)&script->buffer);

	printf ("entering %s\n", script->filename);

	script->line = 1;

	script->script_p = script->buffer;
	script->end_p = script->buffer + size;
}


/*
==============
LoadScriptFile
==============
*/
void LoadScriptFile (char *filename)
{
	script = scriptstack;
	AddScriptToStack (filename);

	endofscript = false;
	tokenready = false;
}


/*
==============
ParseFromMemory
==============
*/
void ParseFromMemory (char *buffer, int size)
{
	script = scriptstack;
	script++;
	if (script == &scriptstack[MAX_INCLUDES])
		Error ("script file exceeded MAX_INCLUDES");
	strcpy (script->filename, "memory buffer" );

	script->buffer = buffer;
	script->line = 1;
	script->script_p = script->buffer;
	script->end_p = script->buffer + size;

	endofscript = false;
	tokenready = false;
}


/*
==============
UnGetToken

Signals that the current token was not used, and should be reported
for the next GetToken.  Note that

GetToken (true);
UnGetToken ();
GetToken (false);

could cross a line boundary.
==============
*/
void UnGetToken (void)
{
	tokenready = true;
}


qboolean EndOfScript (qboolean crossline)
{
	if (!crossline)
		Error ("Line %i is incomplete\n",scriptline);

	if (!strcmp (script->filename, "memory buffer"))
	{
		endofscript = true;
		return false;
	}

	free (script->buffer);
	if (script == scriptstack+1)
	{
		endofscript = true;
		return false;
	}
	script--;
	scriptline = script->line;
	printf ("returning to %s\n", script->filename);
	return GetToken (crossline);
}

/*
==============
GetToken
==============
*/
qboolean GetToken (qboolean crossline)
{
	char    *token_p;

	if (tokenready)                         // is a token allready waiting?
	{
		tokenready = false;
		return true;
	}

	if (script->script_p >= script->end_p)
		return EndOfScript (crossline);

//
// skip space
//
skipspace:
	while (*script->script_p <= 32)
	{
		if (script->script_p >= script->end_p)
			return EndOfScript (crossline);
		if (*script->script_p++ == '\n')
		{
			if (!crossline)
				Error ("Line %i is incomplete\n",scriptline);
			scriptline = script->line++;
		}
	}

	if (script->script_p >= script->end_p)
		return EndOfScript (crossline);

	if (*script->script_p == ';' || *script->script_p == '#' ||		 // semicolon and # is comment field
		(*script->script_p == '/' && *((script->script_p)+1) == '/')) // also make // a comment field
	{											
		if (!crossline)
			Error ("Line %i is incomplete\n",scriptline);
		while (*script->script_p++ != '\n')
			if (script->script_p >= script->end_p)
				return EndOfScript (crossline);
		goto skipspace;
	}

//
// copy token
//
	token_p = token;

	if (*script->script_p == '"')
	{
		// quoted token
		script->script_p++;
		while (*script->script_p != '"')
		{
			*token_p++ = *script->script_p++;
			if (script->script_p == script->end_p)
				break;
			if (token_p == &token[MAXTOKEN])
				Error ("Token too large on line %i\n",scriptline);
		}
		script->script_p++;
	}
	else	// regular token
	while ( *script->script_p > 32 && *script->script_p != ';')
	{
		*token_p++ = *script->script_p++;
		if (script->script_p == script->end_p)
			break;
		if (token_p == &token[MAXTOKEN])
			Error ("Token too large on line %i\n",scriptline);
	}

	*token_p = 0;

	if (!strcmp (token, "$include"))
	{
		GetToken (false);
		AddScriptToStack (token);
		return GetToken (crossline);
	}

	return true;
}


/*
==============
TokenAvailable

Returns true if there is another token on the line
==============
*/
qboolean TokenAvailable (void)
{
	char    *search_p;

	search_p = script->script_p;

	if (search_p >= script->end_p)
		return false;

	while ( *search_p <= 32)
	{
		if (*search_p == '\n')
			return false;
		search_p++;
		if (search_p == script->end_p)
			return false;

	}

	if (*search_p == ';')
		return false;

	return true;
}