/* This file is part of Eclat
   Copyright (C) 2012-2014 Sergey Poznyakoff
 
   Eclat 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, or (at your option)
   any later version.
 
   Eclat 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 Eclat.  If not, see <http://www.gnu.org/licenses/>. */

#include <config.h>
#include "libeclat.h"
#include <ctype.h>

#define NODEREF_TEXT 0x01 /* Text is being constructed */

struct eclat_partial_tree {
	int flags;
	struct grecs_txtacc *acc;
	struct grecs_symtab *texttab;
	struct grecs_list *stack; /* Node stack */
};

static void
pt_free_node(void *ptr)
{
	struct grecs_node *node = ptr;
	grecs_node_free(node);
}

struct eclat_partial_tree *
eclat_partial_tree_create()
{
	struct eclat_partial_tree *pt = grecs_zalloc(sizeof(*pt));
	pt->acc = grecs_txtacc_create();
	pt->stack = grecs_list_create();
	pt->stack->free_entry = pt_free_node;
	return pt;
}

void
eclat_partial_tree_destroy(struct eclat_partial_tree *pt)
{
	grecs_txtacc_free(pt->acc);
	if (pt->texttab)
		grecs_symtab_free(pt->texttab);
	grecs_list_free(pt->stack);
	free(pt);
}

struct grecs_node *
eclat_partial_tree_finish(struct eclat_partial_tree *pt)
{
	struct grecs_node *root = grecs_node_create(grecs_node_root, NULL);
	root->v.texttab = pt->texttab;
	pt->texttab = NULL;
	grecs_node_bind(root, grecs_list_pop(pt->stack), 1);
	eclat_partial_tree_destroy(pt);
	return root;
}


static struct grecs_node *
gettos(struct eclat_partial_tree *nref)
{
	if (nref->stack->head)
		return nref->stack->head->data;
	return NULL;
}

void
eclat_partial_tree_data_handler(void *data, const XML_Char *s, int len)
{
	struct eclat_partial_tree *noderef = data;

	grecs_txtacc_grow(noderef->acc, s, len);
	noderef->flags |= NODEREF_TEXT;
}

/* Start handler: create a node and push it on stack */
void
eclat_partial_tree_start_handler(void *data, const XML_Char *name,
				 const XML_Char **atts)
{
	struct eclat_partial_tree *noderef = data;
	struct grecs_node *node;

	if (noderef->flags & NODEREF_TEXT) {
		grecs_txtacc_free_string(noderef->acc,
					 grecs_txtacc_finish(noderef->acc, 0));
		noderef->flags &= ~NODEREF_TEXT;
	}
	
	node = grecs_node_create((enum grecs_node_type)-1, NULL);
	node->ident = grecs_strdup(name);
	grecs_list_push(noderef->stack, node);
	noderef->flags &= ~NODEREF_TEXT;
}

void
eclat_partial_tree_end_handler(void *data, const XML_Char *name)
{
	struct eclat_partial_tree *noderef = data;
	struct grecs_node *node = grecs_list_pop(noderef->stack);
	struct grecs_node *tos = gettos(noderef);

	if (noderef->flags & NODEREF_TEXT) {
		char *s, *p;
		grecs_value_t *ptr;
		
		grecs_txtacc_grow_char(noderef->acc, 0);
		s = grecs_txtacc_finish(noderef->acc, 1);

		for (p = s; *p && isspace(*p); p++)
			;
		if (!*p) {
			free(s);
			if (node->type == -1)
				node->type = grecs_node_block;
		} else {
			switch (node->type) {
			default:
				node->type = grecs_node_stmt;
				ptr = grecs_malloc(sizeof(*ptr));
				ptr->type = GRECS_TYPE_STRING;
				ptr->v.string = s;
				node->v.value = ptr;
				break;
				
			case grecs_node_root:
				abort(); /* should not happen */

			case grecs_node_stmt:
			case grecs_node_block:
				/* FIXME: error message */
				/* ignoring additional textual data */
				free(s);
			}
		}
		noderef->flags &= ~NODEREF_TEXT;
	} else if (node->type == (enum grecs_node_type)-1)
		node->type = grecs_node_block;

	if (!tos)
		grecs_list_push(noderef->stack, node);
	else {
		switch (tos->type) {
		default:
			tos->type = grecs_node_block;
			break;
		case grecs_node_root:
			abort(); /* should not happen */
		case grecs_node_stmt:
			/* FIXME: error message */
			/* ignoring additional textual data */
			grecs_value_free(tos->v.value);
			tos->type = grecs_node_block;
			break;
		}
		
		grecs_node_bind(tos, node, 1);
	}
}