/*
 * Copyright (C) 2021  P. J. McDermott
 *
 * This file is part of Dodge Balls
 *
 * Dodge Balls 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.
 *
 * Dodge Balls 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 Dodge Balls.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <expat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dirs.h"
#include "map.h"
#include "output.h"
#include "xml.h"

struct db_map {
};

static char *
_db_map_path(const char *game_id, const char *file, const char *ext)
{
	const char *games_dir;
	char       *path;

	games_dir = db_get_games_dir();

	path = malloc((strlen(games_dir) + strlen(game_id) + strlen(file) +
				strlen(ext) + 3) * sizeof(*path));
	if (path == NULL) {
		db_err("Failed to allocate memory");
		return NULL;
	}

	sprintf(path, "%s/%s/%s%s", games_dir, game_id, file, ext);

	return path;
}

static void XMLCALL
_db_tmx_invalid_end(void *pv, const char *name)
{
	XML_Parser p;

	db_dbg("  </%s> (invalid)", name);

	p = (XML_Parser) pv;

	db_xml_unexpected_end_tag(p, name, "");
}

static void XMLCALL
_db_tmx_invalid_start(void *pv, const char *name,
		const char **attr __attribute__((__unused__)))
{
	XML_Parser p;

	db_dbg("  <%s> (invalid)", name);

	p = (XML_Parser) pv;

	db_xml_node_push(p, NULL, _db_tmx_invalid_start,
			_db_tmx_invalid_end, NULL);
}

static void XMLCALL
_db_tmx_map_end(void *pv, const char *name)
{
	XML_Parser p;

	db_dbg("  </%s> (map)", name);

	p = (XML_Parser) pv;

	if (db_xml_check_tag(name, "map")) {
		db_xml_node_pop(p);
	} else {
		db_xml_unexpected_end_tag(p, name, "map");
	}
}

static void XMLCALL
_db_tmx_map_start(void *pv, const char *name,
		const char **attr __attribute__((__unused__)))
{
	XML_Parser      p;
	struct db_map *map;

	db_dbg("  <%s> (map)", name);

	p = (XML_Parser) pv;
	map = db_xml_node_peek(p);

	if (db_xml_check_tag(name, "map")) {
		db_xml_node_push(p, map, _db_tmx_invalid_start,
				_db_tmx_map_end, NULL);
	} else {
		db_xml_unexpected_start_tag(p, name, "map");
	}
}

struct db_map *
db_map_new(const char *game_id, const char *level_id)
{
	struct db_map   *map;
	XML_Parser       p;
	char            *path;
	FILE            *fp;
	void            *buf;
	size_t           len;
	enum XML_Status  status;

	map = calloc(1, sizeof(*map));
	if (map == NULL) {
		db_err("Failed to allocate memory");
		return NULL;
	}

	p = XML_ParserCreate(NULL);
	if (p == NULL) {
		free(map);
		return NULL;
	}
	XML_UseParserAsHandlerArg(p);
	db_xml_node_push(p, map, _db_tmx_map_start, _db_tmx_invalid_end, NULL);

	path = _db_map_path(game_id, level_id, ".tmx");
	if (path == NULL) {
		db_xml_node_pop(p);
		XML_ParserFree(p);
		free(path);
		free(map);
		return NULL;
	}

	fp = fopen(path, "rb");
	if (fp == NULL) {
		db_xml_node_pop(p);
		XML_ParserFree(p);
		free(path);
		free(map);
		return NULL;
	}

	buf = XML_GetBuffer(p, 8192);
	if (buf == NULL) {
		db_xml_node_pop(p);
		XML_ParserFree(p);
		free(path);
		fclose(fp);
		free(map);
		return NULL;
	}

	db_dbg("Parsing <%s>:", path);
	free(path);

	while (!feof(fp)) {
		len = fread(buf, 1, 8192, fp);
		status = XML_ParseBuffer(p, len, feof(fp));
		if (status == XML_STATUS_OK) {
			continue;
		}
		db_err("Failed to parse map information (%s)",
				XML_ErrorString(XML_GetErrorCode(p)));
		db_xml_node_pop(p);
		XML_ParserFree(p);
		fclose(fp);
		free(map);
		return NULL;
	}

	db_dbg("Parsing done");

	db_xml_node_pop(p);
	XML_ParserFree(p);
	fclose(fp);

	return map;
}