/* grecs - Gray's Extensible Configuration System
   Copyright (C) 2007-2011 Sergey Poznyakoff

   Grecs 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.

   Grecs 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 Grecs. If not, see <http://www.gnu.org/licenses/>. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include "grecs.h"
#include "wordsplit.h"

static int
_grecs_list_eq(struct grecs_value *a, struct grecs_value *b)
{
	struct grecs_list_entry *aent, *bent;
	if (grecs_list_size(a->v.list) != grecs_list_size(b->v.list))
		return 0;

	for (aent = a->v.list->head, bent = b->v.list->head;;
	     aent = aent->next, bent = bent->next) {
		if (!aent)
			return bent == NULL;
		if (!bent)
			return 0;
		if (!grecs_value_eq(aent->data, bent->data))
			return 0;
	}
	/*notreached*/
	return 1;
}

static int
_grecs_array_eq(struct grecs_value *a, struct grecs_value *b)
{
	size_t i;

	if (a->v.arg.c != b->v.arg.c)
		return 0;

	for (i = 0; i < a->v.arg.c; i++)
		if (!grecs_value_eq(a->v.arg.v[i], b->v.arg.v[i]))
			return 0;
	return 1;
}

/* Return 1 if configuration value A equals B */
int
grecs_value_eq(struct grecs_value *a, struct grecs_value *b)
{
	if (a->type != b->type)
		return 0;
	switch (a->type) {
	case GRECS_TYPE_STRING:
		if (a->v.string == NULL)
			return b->v.string == NULL;
		return strcmp(a->v.string, b->v.string) == 0;
      
	case GRECS_TYPE_LIST:
		return _grecs_list_eq(a, b);
      
	case GRECS_TYPE_ARRAY:
		return _grecs_array_eq(a, b);
    }
  return 0;
}


static int
split_cfg_path(const char *path, int *pargc, char ***pargv)
{
	int argc;
	char **argv;
	char *delim = ".";
	char static_delim[2] = { 0, 0 };
  
	if (path[0] == '\\') {
		argv = calloc(2, sizeof (*argv));
		if (!argv)
			return ENOMEM;
		argv[0] = strdup(path + 1);
		if (!argv[0]) {
			free(argv);
			return ENOMEM;
		}
		argv[1] = NULL;
		argc = 1;
	} else {
		struct wordsplit ws;
		
		if (ispunct(path[0])) {
			delim = static_delim;
			delim[0] = path[0];
			path++;
		}
		ws.ws_delim = delim;
      
		if (wordsplit(path, &ws, WRDSF_DEFFLAGS|WRDSF_DELIM))
			return errno;
		argc = ws.ws_wordc;
		argv = ws.ws_wordv;
		ws.ws_wordc = 0;
		ws.ws_wordv = NULL;
		wordsplit_free(&ws);
	}
  
	*pargc = argc;
	*pargv = argv;
	
	return 0;
}

static struct grecs_value *
parse_label(const char *str)
{
	struct grecs_value *val = NULL;
	size_t i;
	struct wordsplit ws;
	size_t len = strlen (str);
  
	if (len > 1 && str[0] == '(' && str[len-1] == ')') {
		struct grecs_list *lst;
      
		ws.ws_delim = ",";
		if (wordsplit_len (str + 1, len - 2, &ws,
				      WRDSF_DEFFLAGS|WRDSF_DELIM|
				      WRDSF_WS)) {
			return NULL;
		}

		lst = grecs_value_list_create();
		for (i = 0; i < ws.ws_wordc; i++) {
			struct grecs_value *p = grecs_malloc(sizeof(*p));
			p->type = GRECS_TYPE_STRING;
			p->v.string = ws.ws_wordv[i];
			grecs_list_append(lst, p);
		}
		val = grecs_malloc(sizeof(*val));
		val->type = GRECS_TYPE_LIST;
		val->v.list = lst;
	} else {      
		if (wordsplit(str, &ws, WRDSF_DEFFLAGS))
			return NULL;
		val = grecs_malloc(sizeof(*val));
		if (ws.ws_wordc == 1) {
			val->type = GRECS_TYPE_STRING;
			val->v.string = ws.ws_wordv[0];
		} else {
			val->type = GRECS_TYPE_ARRAY;
			val->v.arg.c = ws.ws_wordc;
			val->v.arg.v = grecs_calloc(ws.ws_wordc,
						    sizeof(val->v.arg.v[0]));
			for (i = 0; i < ws.ws_wordc; i++) {
				val->v.arg.v[i]->type = GRECS_TYPE_STRING;
				val->v.arg.v[i]->v.string = ws.ws_wordv[i];
			}
		}
		ws.ws_wordc = 0;
		wordsplit_free(&ws);
	}
	return val;
}


struct find_closure {
	int argc;
	char **argv;
	int tag;
	struct grecs_value *label;
	struct grecs_node *node;
};

static void
parse_tag(struct find_closure *fptr)
{
	char *p = strchr(fptr->argv[fptr->tag], '=');
	if (p) {
		*p++ = 0;
		fptr->label = parse_label(p);
	}
	else
		fptr->label = NULL;
}

static enum grecs_tree_recurse_res
node_finder(enum grecs_tree_recurse_op op, struct grecs_node *node, void *data)
{
	struct find_closure *fdptr = data;

	if (op == grecs_tree_recurse_post || node->type == grecs_node_root)
		return grecs_tree_recurse_ok;
	
	if (strcmp(fdptr->argv[fdptr->tag], node->ident) == 0
	    && (!fdptr->label ||
		grecs_value_eq(fdptr->label, node->v.value))) {
		fdptr->tag++;
		if (fdptr->tag == fdptr->argc) {
			fdptr->node = node;
			return grecs_tree_recurse_stop;
		}
		parse_tag(fdptr);
		return grecs_tree_recurse_ok;
	}
  
	return node->type == grecs_node_block ?
		grecs_tree_recurse_skip : grecs_tree_recurse_ok;
}

struct grecs_node *
grecs_find_node(struct grecs_node *node, const char *path)
{
	int rc, i;
	struct find_closure clos;
  
	rc = split_cfg_path(path, &clos.argc, &clos.argv);
	if (rc || !clos.argc)
		return NULL;
	clos.tag = 0;
	clos.label = NULL;
	clos.node = NULL;
	parse_tag(&clos);
	grecs_tree_recurse(node, node_finder, &clos);
	for (i = 0; i < clos.argc; i++)
		free(clos.argv[i]);
	free(clos.argv);
	grecs_value_free(clos.label);
	return clos.node;
}
	

struct grecs_node *
grecs_node_from_path(const char *path, const char *value)
{
	int rc;
	int i;
	int argc;
	char **argv;
	struct grecs_node *dn = NULL;
	
	rc = split_cfg_path(path, &argc, &argv);
	if (rc)
		return NULL;
	dn = grecs_node_create(grecs_node_stmt, NULL);
	dn->ident = argv[argc - 1];
	if (value) {
		struct grecs_value *gval = parse_label(value);
		dn->v.value = gval;
	} else
		dn->v.value = NULL;		
	
	for (i = argc - 2; i >= 0; i--) {
		struct grecs_value *label = NULL;
		struct grecs_node *node;
		char *p, *q = argv[i];

		do {
			p = strchr(q, '=');
			if (p && p > argv[i] && p[-1] != '\\') {
				*p++ = 0;
				label = parse_label(p);
				break;
			} else if (p)
				q = p + 1;
			else
				break;
		} while (*q);
		
		node = grecs_node_create(grecs_node_block, NULL);
		node->ident = argv[i];
		if (label)
			node->v.value = label;

		node->down = dn;
		if (dn)
			dn->up = node;
		dn = node;
	}
	
	free(argv);
	return dn;
}