/* Copyright Yann Weber <asmsh@yannweb.net>
   This file is part of asmsh.

   asmsh 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 any later version.
   
   asmsh 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 asmsh. If not, see <https://www.gnu.org/licenses/>.
*/
#include "completion.h"


char **asmsh_completion(const char *buf, const char *text, int start, int end)
{
	if(end == 0)
	{
		// TODO catenate all !
		return asmsh_compl_instr(text);
	}
	if(*buf != '.')
	{
		if(start == 0)
		{
			return asmsh_compl_instr(text);
		}
		return asmsh_compl_arg(buf, text, start);
	}
	// command completion handling
}


/// Replace uppper char leading macro if needed
static int _completion_upper_macro(const char *macro, const char *start, char **ret, size_t *i);
char **asmsh_compl_instr(const char *start)
{
	const size_t icount = sizeof(x86_64_instr)/sizeof(*x86_64_instr);
	size_t i,j;
	char **ret;
	int start_len, cmp;
	ret = malloc(icount * 2 * sizeof(char*));
	bzero(ret, icount * sizeof(char*));
	if(!ret)
	{
		perror("Unable to allocate completion result");
		return NULL;
	}
	if(!start || !*start)
	{
		i=0;
		for(j=0; j<icount; j++)
		{
			if(x86_64_instr[j].mnemo)
			{
				int mret = _completion_upper_macro(
					x86_64_instr[j].mnemo,
					"", ret, &i);
				if(mret < 0)
				{
					goto err_strdup;
				}
				else if(mret == 0)
				{
					ret[i] = strdup(x86_64_instr[j].mnemo);
					if(!ret[i])
					{
						goto err_strdup;
					}
					i++;
				}
			}
			else
			{
				ret[i] = NULL;
			}
		}
		return ret;
	}
	else
	{
		start_len = strlen(start);
		i=0;
		for(j=0; x86_64_instr[j].mnemo; j++)
		{

			int mret = _completion_upper_macro(
					x86_64_instr[j].mnemo,
					start, ret, &i);
			if(mret < 0)
			{
				goto err_strdup;
			}
			else if(mret > 0)
			{
				continue; // handled by macro
			}
			// normal comparison
			cmp = strncmp(start, x86_64_instr[j].mnemo, start_len);
			if(cmp == 0)
			{
				ret[i]=strdup(x86_64_instr[j].mnemo);
				if(!ret[i])
				{
					goto err_strdup;
				}
				i++;
			}
			else if (cmp < 0)
			{
				break;
			}
		}
	}
	return ret;

err_strdup:
	perror("Error while copying string for completion");
	i--;
	do
	{
		free(ret[i]);
	}while(i>0);
	free(ret);
	return NULL;
}



/// match against macro
static int _completion_macro_match(const char *macro, const char *buf, int mlen);
char **asmsh_compl_arg(const char *buf, const char *text, int start)
{
	const asmsh_compinstr_t *match = NULL;
	int argno;
	int i, tlen;
	int matchlen = 0;
	int macro = 0;

	char **ret = malloc(sizeof(char*)*512); /* large enough */
	if(!ret)
	{
		perror("unable to allocate buffer");
		return NULL;
	}
	bzero(ret, sizeof(char*)*512);

	tlen = text?strlen(text):0;

	for(int i=0; i<(sizeof(x86_64_instr)/sizeof(*x86_64_instr))-1; i++)
	{
		int cmp;
		const char *instr = x86_64_instr[i].mnemo;
		int ilen = strlen(instr);
		macro=0;
		if(instr[ilen-1] >= 'A' && instr[ilen-1] <= 'Z')
		{
			ilen--;
			macro = 1;
			cmp = _completion_macro_match(instr, buf, ilen);
			if(cmp < 0)
			{
				goto err;
			}
		}
		else
		{
			cmp = strncmp(buf, instr, ilen);
		}
		if(cmp < 0)
		{
			break;
		}
		else if(cmp > 0)
		{
			continue;
		}
		else if(!macro && (buf[ilen] != ' ' && buf[ilen] != '\t'))
		{
			continue; //not a full match
		}
		// match or approximate macro match
		match = &x86_64_instr[i];
		matchlen = ilen;
		while(buf[matchlen] && buf[matchlen] != ' ' && buf[matchlen] != '\t')
		{
			matchlen++;
		}
		break;
	}
	if(!match)
	{
		ret = malloc(sizeof(char*));
		*ret = NULL;
		return ret;
	}
	argno=0;
	for(i=matchlen; i<=start; i++)
	{
		if(buf[i] == ',')
		{
			argno=1;
		}
	}

	int args = argno?match->arg2:match->arg1;
	if(macro && match->mnemo[strlen(match->mnemo)-1] == 'S')
	{
		int wreg=ASHCOMP_REGALL;
		switch(buf[matchlen-1])
		{
			case 'b'://M_sizes[0]:
				wreg = ASHCOMP_REG8;
				break;
			case 'w'://M_sizes[1]:
				wreg = ASHCOMP_REG16;
				break;
			case 'd'://M_sizes[2]:
				wreg = ASHCOMP_REG32;
				break;
			case 'q'://M_sizes[3]:
				wreg = ASHCOMP_REG64;
				break;
			default:
				wreg = ASHCOMP_REGALL;
				break;
		}
		args &= (0xff ^ ASHCOMP_REGALL) | wreg;
	}

	i=0;// result index
	for(const asmsh_symtable_elt_t *elt=asmsh_symtable; elt->regs; elt++)
	{
		if(!(elt->flag & args))
		{
			continue;
		}
		if(elt->flag == ASHCOMP_IMM && tlen > 1 && *text=='$')
		{
			// immediate value handling
			continue;
		}
		for(const char * const *r=elt->regs; *r; r++)
		{
			if(tlen && strncmp(text, *r, tlen))
			{
				continue;
			}
			if(!(ret[i] = strdup(*r)))
			{
				goto err_strdup;
			}
			if(argno == 0 && **r == '%')
			{
				//full match on arg0 adding ","
				char *tmp = ret[i];
				char buf[32];
				snprintf(buf, 31, "%s,", tmp);
				ret[i] = strdup(buf);
			}
			i++;
		}
	}
	
	return ret;

err_strdup:
	perror("Unable to strdup arg match");
	i--;
	while(i>=0)
	{
		free(ret[i]);
		i--;
	}
err:
	free(ret);
	return NULL;

}



static int _completion_upper_macro(const char *macro, const char *start, char **ret, size_t *i)
{
	int stlen, len, oi, need_cmp;
	char buf[32]; /* large enough */
	char fmt[32];
	oi = *i;
	len = strlen(macro);
	stlen = strlen(start);

	switch(macro[len-1])
	{
		case 'C':
		case 'S':
			break;
		default:
			return 0;
	}

	need_cmp=1;
	if(len > stlen)
	{
		if(strncmp(start, macro, stlen) == 0)
		{
			need_cmp = 0;
		}
		else
		{
			return 0;
		}
	}
	else
	{
		if(strncmp(start, macro, len-1))
		{
			return 0;
		}
	}
	
	switch(macro[len-1])
	{
		case 'C':
			memcpy(fmt, macro, len-1);
			fmt[len-1]='%';
			fmt[len]='s';
			fmt[len+1]='\0';
			for(const char * const *cc=M_conds; *cc; cc++)
			{
				int r = snprintf(buf, 31, fmt, *cc);
				if(r < 0) { return -1; }
				buf[r] = '\0';
				if(!need_cmp || strncmp(start, buf, r<stlen?r:stlen) == 0)
				{
					ret[*i] = strdup(buf);
					(*i)++;
				}
			}
			break;
		case 'S':
			if(!need_cmp)
			{
				ret[*i] = strdup(macro);
				ret[*i][len-1] = '\0';
				(*i)++;
				for(const char *s=M_sizes; *s; s++)
				{
					if(!(ret[*i] = strdup(macro)))
					{
						return -1;
					}
					ret[*i][len-1] = *s;
					(*i)++;
				}
			}
			else if(stlen == len-1)
			{
				ret[*i] = strdup(macro);
				ret[*i][len-1] = '\0';
				(*i)++;
			}
			else if(stlen == len)
			{
				for(const char *s=M_sizes; *s; s++)
				{
					if(*s == start[len-1])
					{
						if(!(ret[*i]=strdup(macro)))
						{
							return -1;
						}
						ret[*i][len-1]=*s;
						(*i)++;
						break;
					}
				}
			}
			break;
	}
	return 1;
}


static int _completion_macro_match(const char *macro, const char *text, int mlen)
{
	char buf[32];
	memcpy(buf, macro, mlen);
	buf[mlen] = '\0';
	switch(macro[mlen])
	{
		case 'C':
			for(const char * const *cond = M_conds;*cond;cond++)
			{
				int ret=snprintf(&buf[mlen], 31-mlen, "%s", *cond);
				int cmp = strncmp(text, buf, mlen+ret);
				if(cmp ==  0)
				{
					return 0;
				}
			}
			break;
		case 'S':
			for(const char * sz=M_sizes; *sz; sz++)
			{
				buf[mlen] = *sz;
				buf[mlen+1] = '\0';
				int cmp =  strncmp(text, buf, mlen+1);
				if(cmp == 0)
				{
					return 0;
				}
			}
			break;
	}
	return 1;
}