/*
 * Copyright (C) 2013, 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 <SDL.h>
#include <expat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ball.h"
#include "base64.h"
#include "compression.h"
#include "defs.h"
#include "dirs.h"
#include "map.h"
#include "tileset.h"
#include "output.h"
#include "xml.h"

struct db_map_layer {
	Uint32              *tiles;
	char                *encoding;
	char                *compression;
	char                *raw_data;
	struct db_map_layer *next;
};

struct db_map {
	char                *game_id;
	int                  w;
	int                  h;
	int                  tw;
	int                  th;
	Uint8                bg_r;
	Uint8                bg_g;
	Uint8                bg_b;
	int                  fr;
	struct db_tileset   *tileset_head;
	struct db_tileset   *tileset_tail;
	struct db_map_layer *layer_head;
	struct db_map_layer *layer_tail;
	int                  obj_gid;
	char                *obj_type;
	int                  obj_x;
	int                  obj_y;
	int                  obj_r;
	int                  obj_a;
	int                  obj_d;
	int                  obj_sr;
	double               obj_s;
	int                  player_x;
	int                  player_y;
	int                  player_r;
	int                  player_gid;
	int                  target_x;
	int                  target_y;
	int                  target_r;
	int                  target_gid;
	struct db_ball      *ball_head;
	struct db_ball      *ball_tail;
	Uint8               *p_col;
	Uint8               *b_col;
};

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_node_pop(p);
}

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_property_end(void *pv, const char *name)
{
	XML_Parser p;

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

	p = (XML_Parser) pv;

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

static void XMLCALL
_db_tmx_property_start(void *pv, const char *name, const char **attr)
{
	XML_Parser     p;
	struct db_map *map;
	char          *p_name;
	char          *p_type;

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

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

	if (db_xml_check_tag(name, "property")) {
		db_xml_get_string_attr(p, attr, "name", &p_name, 1);
		db_xml_get_string_attr(p, attr, "type", &p_type, 1);
		if (strcmp(p_name, "framerate") == 0) {
			if (strcmp(p_type, "int") != 0) {
				db_err("Framerate must be an integer");
				free(p_name);
				free(p_type);
				XML_StopParser(p, XML_FALSE);
				return;
			}
			db_xml_get_int_attr(p, attr, "value", &map->fr,  1);
			db_dbg("          Framerate: %d", map->fr);
		} else {
			db_dbg("Skipping unknown property \"%s\"", p_name);
		}
		free(p_name);
		free(p_type);
		db_xml_node_push(p, map, _db_tmx_invalid_start,
				_db_tmx_property_end, NULL);
	} else {
		db_xml_unexpected_start_tag(p, name, "property");
	}
}

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

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

	p = (XML_Parser) pv;

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

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

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

	p = (XML_Parser) pv;

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

static void XMLCALL
_db_tmx_cdata(void *pv, const char *s, int len)
{
	XML_Parser      p;
	struct db_map  *map;
	char           *s_z;
	char           *s_z_trimmed;
	char           *s_z_trimmed_end;
	char           *old_data;

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

	s_z = s_z_trimmed = strndup(s, len);

	while(isspace(*s_z_trimmed)) {
		++s_z_trimmed;
		--len;
	}
	if (*s_z_trimmed == '\0') {
		db_dbg("        (null)");
		free(s_z);
		return;
	}
	s_z_trimmed_end = s_z_trimmed + len - 1;
	while (s_z_trimmed_end > s_z_trimmed && isspace(*s_z_trimmed_end)) {
		--s_z_trimmed_end;
	}
	*(s_z_trimmed_end + 1) = '\0';

	db_dbg("        %s", s_z_trimmed);
	if (map->layer_tail->raw_data != NULL &&
			*map->layer_tail->raw_data != '\0') {
		old_data = map->layer_tail->raw_data;
		sprintf(map->layer_tail->raw_data, "%s %s",
				map->layer_tail->raw_data, strdup(s_z_trimmed));
		free(old_data);
	} else {
		map->layer_tail->raw_data = strdup(s_z_trimmed);
	}

	free(s_z);
}

static void XMLCALL
_db_tmx_data_end(void *pv, const char *name)
{
	XML_Parser      p;
	struct db_map  *map;
	size_t          decoded_len;
	size_t          decomp_len;
	char           *decoded_buf;
	char           *decomp_buf;
	size_t          i;

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

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

	if (db_xml_check_tag(name, "data")) {
		decoded_len = strlen(map->layer_tail->raw_data);
		decomp_len = 4 * map->w* map->h;
		db_dbg("        Expected map data size: %zu", decomp_len);
		decoded_buf = malloc(decoded_len + 1);
		if (decoded_buf == NULL) {
			db_warn("        Failed to allocate layer data buffer");
			XML_StopParser(p, XML_FALSE);
			return;
		}
		if (strcmp(map->layer_tail->encoding, "base64") == 0) {
			db_dbg("        Decoding base 64 layer data...");
			db_base64_decode(map->layer_tail->raw_data,
					decoded_buf, decoded_len + 1);
		}
		if (map->layer_tail->compression == NULL) {
			db_dbg("        Layer data already decompressed");
			decomp_buf = decoded_buf;
		} else if (strcmp(map->layer_tail->compression, "zlib") == 0) {
			db_dbg("        Decompressing layer data with zlib...");
			decomp_buf = malloc(decomp_len);
			if (decomp_buf == NULL) {
				db_err("Failed to allocate layer data buffer");
				free(decoded_buf);
				XML_StopParser(p, XML_FALSE);
				return;
			}
			db_decompress(decoded_buf, decoded_len,
					decomp_buf, decomp_len);
			free(decoded_buf);
		} else if (strcmp(map->layer_tail->compression, "gzip") == 0) {
			db_dbg("        Decompressing layer data with gzip...");
			decomp_buf = malloc(decomp_len);
			if (decomp_buf == NULL) {
				db_err("Failed to allocate layer data buffer");
				free(decoded_buf);
				XML_StopParser(p, XML_FALSE);
				return;
			}
			db_decompress(decoded_buf, decoded_len,
					decomp_buf, decomp_len);
			free(decoded_buf);
		} else {
			/* This should never happen.  This branch exists only to
			 * silence GCC's maybe-uninitialized warning on
			 * decomp_buf below. */
			return;
		}
		free(map->layer_tail->raw_data);
		map->layer_tail->tiles = malloc(decomp_len);
		for (i = 0; i < decomp_len / 4; ++i) {
			/* Convert each tile GID to the system's byte order. */
			map->layer_tail->tiles[i] =
				(decomp_buf[i * 4 + 0] & 0xFF << 000) |
				(decomp_buf[i * 4 + 1] & 0xFF << 010) |
				(decomp_buf[i * 4 + 2] & 0xFF << 020) |
				(decomp_buf[i * 4 + 3] & 0xFF << 030);
		}
		free(decomp_buf);
		db_xml_node_pop(p);
	} else {
		db_xml_unexpected_end_tag(p, name, "data");
	}
}

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

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

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

	if (db_xml_check_tag(name, "data")) {
		map->layer_tail = calloc(1, sizeof(*map->layer_tail));
		if (map->layer_tail == NULL) {
			XML_StopParser(p, XML_FALSE);
			return;
		}
		if (map->layer_head == NULL) {
			map->layer_head = map->layer_tail;
		}
		db_xml_get_string_attr(p, attr, "encoding",
				&map->layer_tail->encoding, 1);
		db_xml_get_string_attr(p, attr, "compression",
				&map->layer_tail->compression, 0);
		db_xml_node_push(p, map, _db_tmx_invalid_start,
				_db_tmx_data_end, _db_tmx_cdata);
	} else {
		db_xml_unexpected_start_tag(p, name, "data");
	}
}

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

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

	p = (XML_Parser) pv;

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

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

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

	p = (XML_Parser) pv;

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

static void XMLCALL
_db_tmx_object_property_start(void *pv, const char *name, const char **attr)
{
	XML_Parser     p;
	struct db_map *map;
	char          *p_name;
	char          *p_type;
	char          *dir;

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

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

	if (db_xml_check_tag(name, "property")) {
		db_xml_get_string_attr(p, attr, "name", &p_name, 1);
		if (strcmp(p_name, "type") == 0) {
			db_xml_get_string_attr(p, attr, "value", &map->obj_type,
					1);
			db_dbg("              Object type: %s", map->obj_type);
		} else if (strcmp(p_name, "speed") == 0) {
			db_xml_get_string_attr(p, attr, "type", &p_type, 1);
			if (strcmp(p_type, "int") == 0) {
				db_xml_get_int_attr(p, attr, "value",
						(int *) &map->obj_s, 1);
			} else if (strcmp(p_type, "float") == 0) {
				db_xml_get_float_attr(p, attr, "value",
						(float *) &map->obj_s, 1);
			} else {
				db_err("Object speed must be an integer or "
						"float");
				free(p_name);
				free(p_type);
				XML_StopParser(p, XML_FALSE);
				return;
			}
			free(p_type);
			db_dbg("              Object speed: %f", map->obj_s);
		} else if (strcmp(p_name, "direction") == 0) {
			db_xml_get_string_attr(p, attr, "value", &dir, 1);
			if (strcmp(dir, "lr") == 0) {
				map->obj_a = (rand() / (RAND_MAX / 2)) * 180.0;
				db_dbg("              Object direction: "
						"left and right");
			} else if (strcmp(dir, "ud") == 0) {
				map->obj_a = (rand() / (RAND_MAX / 2)) * 180.0 +
					90.0;
				db_dbg("              Object direction: "
						"up and down");
			} else if (strcmp(dir, "random") == 0) {
				map->obj_a = rand() / (RAND_MAX / 360);
				db_dbg("              Object direction: "
						"random");
			} else if (strcmp(dir, "cw") == 0) {
				map->obj_a = rand() / (RAND_MAX / 360);
				map->obj_d = -1;
				db_dbg("              Object direction: "
						"clockwise");
			} else if (strcmp(dir, "ccw") == 0) {
				map->obj_a = rand() / (RAND_MAX / 360);
				map->obj_d =  1;
				db_dbg("              Object direction: "
						"counter-clockwise");
			}
		} else if (strcmp(p_name, "radius") == 0) {
			db_xml_get_string_attr(p, attr, "type", &p_type, 1);
			if (strcmp(p_type, "int") != 0) {
				db_err("Object spin radius must be an integer");
				free(p_name);
				free(p_type);
				XML_StopParser(p, XML_FALSE);
				return;
			}
			free(p_type);
			db_xml_get_int_attr(p, attr, "value", &map->obj_sr, 1);
			db_dbg("              Object spin radius: %d",
					map->obj_sr);
		} else {
			db_dbg("Skipping unknown property \"%s\"", p_name);
		}
		free(p_name);
		db_xml_node_push(p, map, _db_tmx_invalid_start,
				_db_tmx_object_property_end, NULL);
	} else {
		db_xml_unexpected_start_tag(p, name, "property");
	}
}

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

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

	p = (XML_Parser) pv;

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

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

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

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

	if (db_xml_check_tag(name, "properties")) {
		db_xml_node_push(p, map, _db_tmx_object_property_start,
				_db_tmx_object_properties_end, NULL);
	} else {
		db_xml_unexpected_start_tag(p, name, "properties");
	}
}

static void XMLCALL
_db_tmx_object_end(void *pv, const char *name)
{
	XML_Parser     p;
	struct db_map *map;

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

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

	if (db_xml_check_tag(name, "object")) {
		if (strcmp(map->obj_type, "player") == 0) {
			map->player_x   = map->obj_x;
			map->player_y   = map->obj_y;
			map->player_r   = map->obj_r;
			map->player_gid = map->obj_gid;
		} else if (strcmp(map->obj_type, "target") == 0) {
			map->target_x   = map->obj_x;
			map->target_y   = map->obj_y;
			map->target_r   = map->obj_r;
			map->target_gid = map->obj_gid;
		} else if (strcmp(map->obj_type, "ball") == 0) {
			map->ball_tail = db_ball_new(map->obj_x, map->obj_y,
					map->obj_r, map->obj_a, map->obj_d,
					map->obj_sr, map->obj_s,
					map->tileset_head, map->obj_gid,
					map->ball_tail);
			if (map->ball_tail == NULL) {
				XML_StopParser(p, XML_FALSE);
				free(map->obj_type);
				return;
			}
			if (map->ball_head == NULL) {
				map->ball_head = map->ball_tail;
			}
		}
		free(map->obj_type);
		db_xml_node_pop(p);
	} else {
		db_xml_unexpected_end_tag(p, name, "object");
	}
}

static void XMLCALL
_db_tmx_object_start(void *pv, const char *name, const char **attr)
{
	XML_Parser     p;
	struct db_map *map;
	int            x;
	int            y;
	int            w;
	int            h;

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

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

	if (db_xml_check_tag(name, "object")) {
		db_xml_get_int_attr(p, attr, "gid", &map->obj_gid, 1);
		db_xml_get_int_attr(p, attr, "x",      &x, 1);
		db_xml_get_int_attr(p, attr, "y",      &y, 1);
		db_xml_get_int_attr(p, attr, "width",  &w, 1);
		db_xml_get_int_attr(p, attr, "height", &h, 1);
		if (w != h) {
			db_err("Objects must be circular");
			XML_StopParser(p, XML_FALSE);
			return;
		}
		map->obj_x  = x + w / 2;
		map->obj_y  = y - h / 2;  /* Object origin is BOTTOM left */
		map->obj_r  = w / 2;
		map->obj_a  = 0;
		map->obj_d  = 0;
		map->obj_sr = 0;
		map->obj_s  = 0.0;
		db_xml_node_push(p, map, _db_tmx_object_properties_start,
				_db_tmx_object_end, NULL);
	} else {
		db_xml_unexpected_start_tag(p, name, "object");
	}
}

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

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

	p = (XML_Parser) pv;

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

static void XMLCALL
_db_tmx_map_el_start(void *pv, const char *name, const char **attr)
{
	XML_Parser     p;
	struct db_map *map;
	int            firstgid;
	char          *source;

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

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

	if (db_xml_check_tag(name, "properties")) {
		db_xml_node_push(p, map, _db_tmx_property_start,
				_db_tmx_properties_end, NULL);
	} else if (db_xml_check_tag(name, "tileset")) {
		db_xml_get_int_attr(p, attr, "firstgid", &firstgid, 1);
		db_xml_get_string_attr(p, attr, "source", &source, 1);
		db_dbg("        Tileset: <%s>", source);
		map->tileset_tail = db_tileset_new(map->game_id, source,
				firstgid, map->tw, map->th, map->tileset_tail);
		if (map->tileset_head == NULL) {
			map->tileset_head = map->tileset_tail;
		}
		free(source);
		if (map->tileset_tail == NULL) {
			XML_StopParser(p, XML_FALSE);
			return;
		}
		db_xml_node_push(p, map, _db_tmx_invalid_start,
				_db_tmx_tileset_end, NULL);
	} else if (db_xml_check_tag(name, "layer")) {
		db_xml_node_push(p, map, _db_tmx_data_start,
				_db_tmx_layer_end, NULL);
	} else if (db_xml_check_tag(name, "objectgroup")) {
		db_xml_node_push(p, map, _db_tmx_object_start,
				_db_tmx_objectgroup_end, NULL);
	} else {
		db_xml_unexpected_start_tag(p, name,
				"properties, tileset, layer, or objectgroup");
	}
}

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)
{
	XML_Parser     p;
	struct db_map *map;
	char          *orientation;
	char          *renderorder;
	char          *backgroundcolor;
	unsigned int   bg_r;
	unsigned int   bg_g;
	unsigned int   bg_b;

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

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

	if (db_xml_check_tag(name, "map")) {
		/* Check orientation */
		db_xml_get_string_attr(p, attr, "orientation", &orientation, 1);
		if (strcmp(orientation, "orthogonal") != 0) {
			db_err("Map must be orthogonal");
			XML_StopParser(p, XML_FALSE);
			return;
		}
		free(orientation);
		/* Check render order */
		db_xml_get_string_attr(p, attr, "renderorder", &renderorder, 1);
		if (strcmp(renderorder, "right-down") != 0) {
			db_err("Map must be rendered right-down");
			XML_StopParser(p, XML_FALSE);
			return;
		}
		free(renderorder);
		/* Get and check size */
		db_xml_get_int_attr(p, attr, "width",      &map->w,  1);
		db_xml_get_int_attr(p, attr, "height",     &map->h,  1);
		db_xml_get_int_attr(p, attr, "tilewidth",  &map->tw, 1);
		db_xml_get_int_attr(p, attr, "tileheight", &map->th, 1);
		if (map->w * map->tw != DB_WINDOW_W ||
				map->h * map->th != DB_WINDOW_H) {
			db_err("Map size must be %dx%d px",
					DB_WINDOW_W, DB_WINDOW_H);
			XML_StopParser(p, XML_FALSE);
			return;
		}
		db_dbg("      Map size:  %dx%d px", map->w,  map->h);
		db_dbg("      Tile size: %dx%d px", map->tw, map->th);
		/* Get and check background color */
		db_xml_get_string_attr(p, attr, "backgroundcolor",
				&backgroundcolor, 1);
		if (sscanf(backgroundcolor, "#%02x%02x%02x",
					&bg_r, &bg_g, &bg_b) != 3) {
			db_err("Background color must be \"#xxxxxx\"");
			XML_StopParser(p, XML_FALSE);
			return;
		}
		map->bg_r = bg_r;
		map->bg_g = bg_g;
		map->bg_b = bg_b;
		db_dbg("      Background color: (0x%02x, 0x%02x, 0x%02x)",
				map->bg_r, map->bg_g, map->bg_b);
		db_xml_node_push(p, map, _db_tmx_map_el_start,
				_db_tmx_map_end, NULL);
	} else {
		db_xml_unexpected_start_tag(p, name, "map");
	}
}

static void
_db_map_set_collision_tiles(struct db_map *map)
{
	struct db_map_layer *layer;
	int                  i;
	int                  gid;

	db_dbg("Allocating %d bit field elements", (map->w * map->h + 7) / 8);
	map->p_col = calloc((map->w * map->h + 7) / 8, sizeof(*map->p_col));
	if (map->p_col == NULL) {
		db_err("Failed to allocate memory");
		return;
	}
	map->b_col = calloc((map->w * map->h + 7) / 8, sizeof(*map->p_col));
	if (map->b_col == NULL) {
		db_err("Failed to allocate memory");
		free(map->p_col);
		return;
	}

	for (layer = map->layer_head; layer != NULL; layer = layer->next) {
		for (i = 0; i < map->w * map->h; ++i) {
			gid = layer->tiles[i];
			if (gid == 0) {
				continue;
			}
			if (db_tile_player_collides(map->tileset_head, gid)) {
				db_dbg("Tile %d collides: setting bit %d of "
						"field element %d",
						i, i % 8, i / 8);
				map->p_col[i / 8] |= 1 << (i % 8);
			}
			if (db_tile_ball_collides(map->tileset_head, gid)) {
				map->b_col[i / 8] |= 1 << (i % 8);
			}
		}
	}
}

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;
	}

	map->game_id = strdup(game_id);
	if (map->game_id == NULL) {
		db_err("Failed to allocate memory");
		free(map);
		return NULL;
	}

	p = XML_ParserCreate(NULL);
	if (p == NULL) {
		free(map->game_id);
		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->game_id);
		free(map);
		return NULL;
	}

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

	db_dbg("Parsing done");

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

	_db_map_set_collision_tiles(map);

	return map;
}

static int
_db_map_render_layer(struct db_map *map, struct db_map_layer *layer,
		SDL_Renderer *renderer)
{
	int      i;
	int      gid;
	SDL_Rect layer_rect;

	for (i = 0; i < map->w * map->h; ++i) {
		gid = layer->tiles[i];
		if (gid == 0) {
			continue;
		}
		layer_rect.x = map->tw * (i % map->w);
		layer_rect.y = map->th * (i / map->w);
		layer_rect.w = map->tw;
		layer_rect.h = map->th;
		db_tile_render(map->tileset_head, renderer, gid, &layer_rect);
	}

	return 0;
}

SDL_Texture *
db_map_render(struct db_map *map, SDL_Renderer *renderer)
{
	SDL_Texture         *texture;
	SDL_Texture         *old_target;
	struct db_map_layer *layer;

	texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888,
			SDL_TEXTUREACCESS_TARGET, map->w * map->tw,
			map->h * map->th);
	old_target = SDL_GetRenderTarget(renderer);
	SDL_SetRenderTarget(renderer, texture);
	if (SDL_SetRenderDrawColor(renderer,
				map->bg_r, map->bg_g, map->bg_b, 0xFF) != 0) {
		db_err("Failed to set drawing color (%s)", SDL_GetError());
		return NULL;
	}
	if (SDL_RenderClear(renderer) != 0) {
		db_err("Failed to clear texture (%s)", SDL_GetError());
		return NULL;
	}

	for (layer = map->layer_head; layer != NULL; layer = layer->next) {
		if (_db_map_render_layer(map, layer, renderer) != 0) {
			return NULL;
		}
	}

	SDL_SetRenderTarget(renderer, old_target);

	return texture;
}

struct db_tileset *
db_map_get_tilesets(struct db_map *map)
{
	return map->tileset_head;
}

void
db_map_get_player(struct db_map *map, int *x, int *y, int *r, int *gid)
{
	*x   = map->player_x;
	*y   = map->player_y;
	*r   = map->player_r;
	*gid = map->player_gid;
}

void
db_map_get_target(struct db_map *map, int *x, int *y, int *r, int *gid)
{
	*x   = map->target_x;
	*y   = map->target_y;
	*r   = map->target_r;
	*gid = map->target_gid;
}

struct db_ball *db_map_get_balls(struct db_map *map)
{
	return map->ball_head;
}