/*
macro.c
Copyright © 2008 William Astle

This file is part of LWASM.

LWASM is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.

You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.

Contains stuff associated with macro processing
*/

#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include "lwasm.h"
#include "instab.h"
#include "util.h"

OPFUNC(pseudo_macro)
{
	macrotab_t *m;

	// if skipping a condition, flag in a macro
	if (as -> skipcond)
	{
		as -> skipmacro = 1;
		return;
	}

	// actually define a macro
	if (as -> inmacro)
	{
		register_error(as, l, 1, "Attempt to define a macro inside a macro");
		return;
	}

	as -> inmacro = 1;

	// don't actually do anything if not pass 1
	if (as -> passnum != 1)
		return;


	if (!l -> sym)
	{
		register_error(as, l, 1, "Macro definition with no effect - no symbol");
		return;
	}
	
	// search for macro by same name...
	for (m = as -> macros; m; m = m -> next)
	{
		if (!strcmp(m -> name, l -> sym))
			break;
	}
	if (m)
	{
		register_error(as, l, 1, "Duplicate macro definition");
		return;
	}
	
	m = lwasm_alloc(sizeof(macrotab_t));
	m -> name = lwasm_strdup(l -> sym);
	m -> next = as -> macros;
	m -> lines = NULL;
	m -> numlines = 0;
	as -> macros = m;

	while (**p && !isspace(**p))
		(*p)++;
}

OPFUNC(pseudo_endm)
{
	if (as -> skipcond)
	{
		as -> skipmacro = 0;
		return;
	}
	
	if (!as -> inmacro)
	{
		register_error(as, l, 1, "ENDM without MACRO");
		return;
	}
	
	as -> inmacro = 0;
	
	// a macro definition counts as a context break for local symbols
	as -> context = lwasm_next_context(as);
}

// the current macro will ALWAYS be the first one in the table
int add_macro_line(asmstate_t *as, char *optr)
{
	if (!as -> inmacro)
		return 0;
	
	if (as -> passnum == 2)
		return 1;

	as -> macros -> lines = lwasm_realloc(as -> macros -> lines, sizeof(char *) * (as -> macros -> numlines + 1));
	as -> macros -> lines[as -> macros -> numlines] = lwasm_strdup(optr);
	as -> macros -> numlines += 1;
	return 1;
}

void macro_add_to_buff(char **buff, int *loc, int *len, char c)
{
	if (*loc == *len)
	{
		*buff = lwasm_realloc(*buff, *len + 32);
		*len += 32;
	}
	(*buff)[(*loc)++] = c;
}

// this is just like a regular operation function
/*
macro args are referenced by "\n" where 1 <= n <= 9
or by "\{n}"; a \ can be included by writing \\
a comma separates argument but one can be included with "\,"
whitespace ends argument list but can be included with "\ " or the like

In pass 1, actually add the lines to the system, in pass 2, do not
In pass 2, track the number of lines to skip because they already will be
processed by this function - this will be in as -> skiplines

*/
int expand_macro(asmstate_t *as, lwasm_line_t *l, char **p, char *opc)
{
	int lc;
	lwasm_line_t *cl, *nl;
	int oldcontext;
	macrotab_t *m;

	char **args = NULL;		// macro arguments
	int nargs = 0;			// number of arguments

	char *p2, *p3;
	
	int bloc, blen;
	char *linebuff;

	for (m = as -> macros; m; m = m -> next)
	{
		if (!strcmp(opc, m -> name))
			break;
	}
	// signal no macro expansion
	if (!m)
		return -1;
	

	// save current symbol context for after macro expansion
	oldcontext = as -> context;

	cl = l;

	as -> context = lwasm_next_context(as);

	// step 1: parse arguments (pass 1 only)
	if (as -> passnum == 1)
	{
		while (**p && !isspace(**p) && **p != ',')
		{
			p2 = *p;
			while (*p2 && !isspace(*p2) && *p2 != ',')
			{
				if (*p2 == '\\')
				{
					if (p2[1])
						p2++;
				}
				p2++;
			}
			
			// have arg here
			args = lwasm_realloc(args, sizeof(char *) * (nargs + 1));
			args[nargs] = lwasm_alloc(p2 - *p + 1);
			args[nargs][p2 - *p] = '\0';
			memcpy(args[nargs], *p, p2 - *p);
			*p = p2;
			
			// now collapse out "\" characters
			for (p3 = p2 = args[nargs]; *p2; p2++, p3++)
			{
				if (*p2 == '\\' && p2[1])
				{
					p2++;
				}
				*p3 = *p2;
			}
			*p3 = '\0';
			
			nargs++;
			if (**p == ',')
				(*p)++;
		}
	}
	
	{
		int i;
		for (i = 0; i < nargs; i++)
		{
			debug_message(10, "Macro (%s) arg %d: %s", m -> name, i + 1, args[i]);
		}
	}
	
	// step 2: iterate over the lines
	if (as -> passnum == 2)
	{
		// pass 2 only - parse the lines and count them
		for (lc = 0; lc < m -> numlines; lc++)
		{
			cl = cl -> next;
			as -> skiplines++;
			lwasm_parse_line(as, cl);
		}
	}
	else
	{
		// pass 1 only - construct the lines and parse them
		for (lc = 0; lc < m -> numlines; lc++)
		{
			nl = lwasm_alloc(sizeof(lwasm_line_t));
			nl -> lineno = lc + 1;
			nl -> filename = m -> name;
			nl -> next = NULL;
			nl -> prev = as -> linestail;
			nl -> err = NULL;
			nl -> fsize = 0;
			nl -> sym = NULL;
			nl -> bytes = NULL;
			nl -> codelen = 0;
			nl -> codesize = 0;
			nl -> nocodelen = 0;
			nl -> addrset = 0;
			nl -> symaddr = -1;
			nl -> badop = 0;
			nl -> relocoff = -1;
			if (as -> linestail)
				as -> linestail -> next = nl;
			as -> linestail = nl;
			if (!(as -> lineshead))
				as -> lineshead = nl;

			bloc = blen = 0;
			linebuff = NULL;
			for (p2 = m -> lines[lc]; *p2; p2++)
			{
				if (*p2 == '\\' && isdigit(p2[1]))
				{
					int n;
					
					p2++;
					n = *p2 - '0';
					if (n == 0)
					{
						for (p3 = m -> name; *p3; p3++)
							macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
						continue;
					}
					if (n < 1 || n > nargs)
						continue;
					for (p3 = args[n - 1]; *p3; p3++)
						macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
					continue;
				}
				else if (*p2 == '{')
				{
					int n = 0, n2;
					p2++;
					while (*p2 && isdigit(*p2))
					{
						n2 = *p2 - '0';
						if (n2 < 0 || n2 > 9)
							n2 = 0;
						n = n * 10 + n2;
						p2++;
					}
					if (*p2 == '}')
						p2++;
					 
					if (n == 0)
					{
						for (p3 = m -> name; *p3; p3++)
							macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
						continue;
					}
					if (n < 1 || n > nargs)
						continue;
					for (p3 = args[n - 1]; *p3; p3++)
						macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
					continue;
				}
				else
				{
					macro_add_to_buff(&linebuff, &bloc, &blen, *p2);
				}
			}

			macro_add_to_buff(&linebuff, &bloc, &blen, 0);
			
			nl -> text = linebuff;

			lwasm_parse_line(as, nl);
			if (as -> endseen)
				break;

		}
	}
	
	// restore context from before the macro was called
	as -> context = oldcontext;

	// clean up
	if (args)
	{
		while (nargs)
		{
			lwasm_free(args[--nargs]);
		}
		lwasm_free(args);
	}

	// indicate a macro was expanded
	return 0;	
}