/*
 * Copyright (C) 2020 Weber Yann
 * 
 * This file is part of pyrpn.
 * 
 * pyrpn 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.
 * 
 * pyrpn 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 pyrpn.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "rpn_parse.h"

/**@brief Macro for @ref rpn_ops member definition
 * @param NAME @ref rpn_lib.h symbol
 * @param s The short (1 char) symbol code
 * @param l The long (char*) symbole code
 */
#define __op(NAME, s, l) {&NAME, &CODE_SZ(NAME), s, l}
const rpn_op_t rpn_ops[] = {\
	__op(rpn_add, '+', "add"),\
	__op(rpn_sub, '-', "sub"),\
	__op(rpn_div, '/', "div"),\
	__op(rpn_mul, '*', "mul"),\
	__op(rpn_mod, '%', "mod"),\
	__op(rpn_neg, '!', "neg"),\
	__op(rpn_not, '~', "not"),\
	__op(rpn_and, '&', "and"),\
	__op(rpn_or, '|', "or"),\
	__op(rpn_xor, '^', "xor"),\
	__op(rpn_shr, 'r', ">>"),\
	__op(rpn_shl, 'l', "<<"),\
	__op(rpn_xchg, 'x', "xchg"),\
	__op(rpn_dup, 'd', "dup"),\
	__op(rpn_pop_op, 'p', "pop"),\
};
#undef __op

int rpn_tokenizer_start(rpn_tokenizer_t *tokenizer, rpn_tokenized_t *dst,
	const char* expr, size_t argc)
{
	int err;

	bzero(tokenizer, sizeof(rpn_tokenizer_t));
	tokenizer->orig = expr;

	tokenizer->toks = dst;
	tokenizer->toks->argc = argc;
	tokenizer->toks->tokens_sz = 0;
	tokenizer->toks->tokens = NULL;


	if(!(tokenizer->buff = strdup(expr)))
	{
		err = errno;
		snprintf(tokenizer->err_reason, 64,
			"Error duplicating expression for tokenization : %s",
			strerror(err));
		errno = err;
		return -1;
	}
	tokenizer->cur = tokenizer->buff;

	return 0;
}

rpn_token_t* rpn_tok(rpn_tokenizer_t *tokenizer)
{
	char *token;
	rpn_token_t ret, *tmp, *res;
	int err;

	token = tokenizer->cur;

	if(!*token) // end of expression
	{
		rpn_tokenizer_free(tokenizer);
		return NULL;
	}

	while(*(tokenizer->cur))
	{
		if(*(tokenizer->cur) == ' ' ||
		   *(tokenizer->cur) == '\n' ||
		   *(tokenizer->cur) == '\t')
		{
			break;
		}
		tokenizer->cur++;
		tokenizer->chr_no++;
	}
	if(*(tokenizer->cur))
	{
		// not end, go on next chr for further rpn_tok calls
		*(tokenizer->cur) = '\0';
		tokenizer->cur++;
		tokenizer->chr_no++;
	}

	// we have a clean token '\0' terminated
	if(rpn_tokenize(token, &ret, tokenizer->err_reason) < 0)
	{
		errno = 0;
		return NULL;
	}
	if(ret.type == RPN_arg && ret.arg_n >= tokenizer->toks->argc)
	{
		// invalid argument number
		if(tokenizer->toks->argc)
		{
			snprintf(tokenizer->err_reason, 64,
"Argument number is too big : should be in [0..%ld] but \"%s\" found",
				tokenizer->toks->argc - 1, token);
		}
		else
		{
			snprintf(tokenizer->err_reason, 64,
				"No argument accepted but \"%s\" found",
				token);
		}
		errno = EINVAL;
		return NULL;
	}

	if(tokenizer->toks->tokens_sz >= tokenizer->allocated_toks)
	{
		tokenizer->allocated_toks += 8;
		tmp = realloc(tokenizer->toks->tokens,
			sizeof(rpn_token_t) * tokenizer->allocated_toks);
		if(!tmp)
		{
			err = errno;
			snprintf(tokenizer->err_reason, 64,
				"Unable to realloc tokens list : %s",
				strerror(err));
			errno = err;
			return NULL;
		}
		tokenizer->toks->tokens = tmp;
	}

	res = &(tokenizer->toks->tokens[tokenizer->toks->tokens_sz]);
	*res = ret;
	tokenizer->toks->tokens_sz++;
	return res;
}

int rpn_tokenize(const char *token, rpn_token_t *dst, char error[64])
{
	int rep;
	unsigned long num;
	const char *orig;

	if((rep = rpn_match_token_i(token)) >= 0)
	{
		dst->type = RPN_op;
		dst->op_n = rep;
		dst->op = &(rpn_ops[rep]);
		return 0;
	}

	orig = token;

	if(*token == 'A')
	{
		if(!token[1])
		{
			snprintf(error, 64,
				"Argument number is missing, lonely \"A \" found");
			return -1;
		}
		dst->type = RPN_arg;
		token++;
	}
	else
	{
		dst->type = RPN_val;
	}

	if(rpn_match_number(token, &num) < 0)
	{
		snprintf(error, 64,
			"Invalid %snumber : \"%s\"",
			dst->type == RPN_arg?"argument ":"constant ",
			orig);
		return -1;
	}
	
	if(dst->type == RPN_arg)
	{
		dst->arg_n = num;
	}
	else
	{
		dst->value = num;
	}
	return 0;
}

void rpn_tokenizer_free(rpn_tokenizer_t *tokenizer)
{
	if(tokenizer->buff)
	{
		free(tokenizer->buff);
		bzero(tokenizer, sizeof(rpn_tokenizer_t));
	}
}

char* rpn_tokenized_expr(rpn_tokenized_t *tokens, char long_op)
{
	size_t expr_sz, i;
	int err, written;
	char *cur, *tmp, *expr;
	rpn_token_t *token;
	int ALLOC_CHUNK=22; /* 64 bit uint is 20 decimal digit */

#ifdef DEBUG
	if(!tokens)
	{
		dprintf(2, "Error, NULL ptr given to rpn_rokenize_expr");
		err = EINVAL;
		goto ret_err;
	}
#endif
	errno = 0;
	err = 0;
	expr_sz = 0;
	expr_sz = 128;
	cur = expr = malloc(sizeof(char)*expr_sz);
	if(!expr)
	{
		err=errno;
		dprintf(2,"Error allocating memory for expression : %s",
			strerror(err));
		goto ret_err;
	}
	for(i=0; i<tokens->tokens_sz; i++)
	{
		token = &(tokens->tokens[i]);
		if(cur - expr >= expr_sz - ALLOC_CHUNK)
		{
			expr_sz += 128;
			tmp = realloc(expr, sizeof(char) * expr_sz);
			if(!tmp)
			{
				err=errno;
				dprintf(2,"Error allocating memory for expression : %s",
					strerror(err));
				goto ret_err;
			}
			cur = tmp + (cur - expr);
			expr = tmp;
		}
		switch(token->type)
		{
			case RPN_op:
				if(!long_op)
				{
					*cur = token->op->chr;
					cur[1] = ' ';
					cur[2] = '\0';
					written = 2;
				}
				else
				{
					written = snprintf(cur, ALLOC_CHUNK,
						"%s ", token->op->str);
					written--;
				}
				break;
			case RPN_arg:
				written = snprintf(cur, ALLOC_CHUNK,
					"A%lu ", token->arg_n);
				break;
			case RPN_val:
				written = snprintf(cur, ALLOC_CHUNK,
					"0x%lX ", token->value);
				break;
			default:
				#ifdef DEBUG
				dprintf(2,
"Invalid token type encountered : %d\n",
					token->type); 
				#endif
				err = EUCLEAN;
				goto free_err;
		}
		#ifdef DEBUG
		if(written > ALLOC_CHUNK)
		{
			dprintf(2, "Expression too long : %s",
				token->op->str);
			err = EINVAL;
			goto free_err;
		}
		#endif
		cur += written;
	}

	return expr;

	free_err:
		free(expr);
	ret_err:
		errno = err;
		return NULL;
}

const rpn_op_t* rpn_match_token(const char* token)
{
	int rep;
	if((rep = rpn_match_token_i(token)) < 0)
	{
		return NULL;
	}
	return &(rpn_ops[rep]);
}

int rpn_match_token_i(const char* token)
{
	unsigned char i;
	if(token[1] == '\0') //strlen(token) == 1
	{
		foreach_rpn_ops(i)
		{
			if(rpn_ops[i].chr == token[0])
			{
				return (int)i;
			}
		}
		return -1;
	}
	foreach_rpn_ops(i)
	{
		if(!strncmp(rpn_ops[i].str, token, 8))
		{
			return (int)i;
		}
	}
	return -1;
}

int rpn_match_number(const char* token, unsigned long *result)
{
	char *endptr;
	unsigned long long res;
	int base;

	if(*token == '\0')
	{
		return -1;
	}
	base = 10;
	if(*token == '0' && token[1] != '\0')
	{
		token++;
		if(*token == 'x')
		{
			token++;
			base = 16;
		}
		else if(*token == 'o')
		{
			token++;
			base = 8;
		}
		else if(*token == 'b')
		{
			token++;
			base = 2;
		}
	}
	res = strtoull(token, &endptr, base);
	if(*endptr != '\0')
	{
		return -1;
	}
	*result = res;
	return 0;
}

size_t rpn_op_sz()
{
	return sizeof(rpn_ops)/sizeof(rpn_op_t);
}