/*
 * Copyright (C) 2013  Patrick "P. J." McDermott
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/>.
 */

#include <expat.h>
#include <config.h>
#include "tileset.h"
#include "resource.h"
#include "tmx.h"
#include "image.h"
#include "../xml.h"
#include "../logging.h"

struct resource_table ts_res;

static void XMLCALL tmx_tileset_start(void *, const char *, const char **);
static void XMLCALL tmx_tileset_end(void *, const char *);
static void XMLCALL tmx_image_end(void *, const char *);
static void XMLCALL tmx_tile_end(void *, const char *);
static void XMLCALL tmx_tile_properties_start(void *, const char *,
		const char **);
static void XMLCALL tmx_tile_property_start(void *, const char *,
		const char **);

struct tileset *
tileset_get(const char *path, const char *basedir)
{
	struct tileset *ts;
	XML_Parser p;
	FILE *tmx_fp;
	void *tmx_buf;
	size_t len;
	enum XML_Status status;

	ts = (struct tileset *) resource_get(&ts_res, path);
	if (ts != NULL) {
		resource_use((struct resource *) ts);
		return ts;
	}

	ts = resource_alloc(path, sizeof(*ts));
	if (ts == NULL) {
		return NULL;
	}
	ts->dirname = strdup(basedir);

	p = XML_ParserCreate(NULL);
	if (p == NULL) {
		warn("Failed to create TSX parser");
		return NULL;
	}

	XML_UseParserAsHandlerArg(p);
	xml_node_push(p, ts, tmx_tileset_start, tmx_invalid_end, NULL);

	tmx_fp = fopen(path, "rb");
	if (tmx_fp == NULL) {
		warn("Failed to open TSX file");
		xml_node_pop(p);
		XML_ParserFree(p);
		return NULL;
	}

	tmx_buf = XML_GetBuffer(p, 8192);
	if (tmx_buf == NULL) {
		warn("Failed to create TSX parse buffer");
		xml_node_pop(p);
		XML_ParserFree(p);
		fclose(tmx_fp);
		return NULL;
	}

	while (!feof(tmx_fp)) {
		len = fread(tmx_buf, 1, 8192, tmx_fp);
		status = XML_ParseBuffer(p, len, feof(tmx_fp));
		if (status == XML_STATUS_OK) {
			continue;
		}
		warn("Failed to parse TSX file (%s)",
				XML_ErrorString(XML_GetErrorCode(p)));
		xml_node_pop(p);
		XML_ParserFree(p);
		fclose(tmx_fp);
		return NULL;
	}

	XML_ParserFree(p);
	fclose(tmx_fp);

	resource_use((struct resource *) ts);
	resource_add(&ts_res, path, (struct resource *) ts);

	return ts;
}

void XMLCALL
tmx_tileset_el_start(void *pv, const char *name, const char **attr)
{
	XML_Parser p = (XML_Parser) pv;
	struct tileset *ts;
	char *dirname;
	char *source;
	char *path;
	struct image *img;

#ifdef DEBUG_TMX
	debug("<%s> (tileset child)", name);
#endif

	ts = xml_node_peek(p);

	if (xml_check_tag(name, "tileoffset")) {
		/* Not used by engine. */
		xml_node_push(p, NULL, tmx_unused_start, tmx_unused_end, NULL);
	} else if (xml_check_tag(name, "properties")) {
		/* Not used by engine. */
		xml_node_push(p, NULL, tmx_unused_start, tmx_unused_end, NULL);
	} else if (xml_check_tag(name, "image")) {
		xml_get_int_attr(p, attr, "width", &ts->width, 1);
		xml_get_int_attr(p, attr, "height", &ts->height, 1);
		ts->width /= ts->tilewidth;
		ts->height /= ts->tileheight;
		img = NULL;
		if (ts->type == TILESET_TYPE_IMAGE) {
			dirname = ts->dirname;
			xml_get_string_attr(p, attr, "source", &source, 0);
			path = malloc(strlen(dirname) + strlen(source) + 2);
			if (path == NULL) {
				return;
			}
			sprintf(path, "%s/%s", dirname, source);
			img = img_png_get(path);
			/* TODO: Get the color key from the trans attribute. */
			SDL_SetColorKey(img->image, SDL_SRCCOLORKEY,
					SDL_MapRGB(img->image->format,
						0xFC, 0x00, 0xFF));
			free(source);
		} else if (ts->type == TILESET_TYPE_COLLISION) {
			ts->collision_tiles = malloc(ts->width * ts->height *
					sizeof(*ts->collision_tiles));
			if (ts->collision_tiles == NULL) {
				return;
			}
		}
		xml_node_push(p, img, tmx_invalid_start, tmx_image_end, NULL);
	} else if (xml_check_tag(name, "tile")) {
		xml_get_int_attr(p, attr, "id", &ts->cur_collision_tile, 1);
		xml_node_push(p, ts, tmx_tile_properties_start, tmx_tile_end,
				NULL);
	} else {
		xml_unexpected_start_tag(p, name, "tileoffset, image, tile");
	}
}

static void XMLCALL
tmx_tileset_start(void *pv, const char *name, const char **attr)
{
	XML_Parser p = (XML_Parser) pv;
	struct tileset *ts;

#ifdef DEBUG_TMX
	debug("<%s> (external tileset)", name);
#endif

	if (xml_check_tag(name, "tileset")) {
		ts = xml_node_peek(p);
		xml_get_string_attr(p, attr, "name", &ts->name, 1);
		xml_get_int_attr(p, attr, "tilewidth", &ts->tilewidth, 1);
		xml_get_int_attr(p, attr, "tileheight", &ts->tileheight, 1);
		if (strcmp(ts->name, "collision") == 0) {
			ts->type = TILESET_TYPE_COLLISION;
		} else {
			ts->type = TILESET_TYPE_IMAGE;
		}
		xml_node_push(p, ts, tmx_tileset_el_start, tmx_tileset_end,
				NULL);
	} else {
		xml_unexpected_start_tag(p, name, "tileset");
	}
}

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

#ifdef DEBUG_TMX
	debug("</%s> (external tileset)", name);
#endif

	if (xml_check_tag(name, "tileset")) {
		xml_node_pop(p);
	} else {
		xml_unexpected_end_tag(p, name, "tileset");
	}
}

static void XMLCALL
tmx_image_end(void *pv, const char *name)
{
	XML_Parser p = (XML_Parser) pv;
	struct image *img;
	struct tileset *ts;

#ifdef DEBUG_TMX
	debug("</%s> (image)", name);
#endif

	if (xml_check_tag(name, "image")) {
		img = (struct image *) xml_node_pop(p);
		ts = (struct tileset *) xml_node_peek(p);
		ts->image = img;
	} else {
		xml_unexpected_end_tag(p, name, "image");
	}
}

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

#ifdef DEBUG_TMX
	debug("</%s> (tile)", name);
#endif

	xml_node_pop(p);

	if (xml_check_tag(name, "tile")) {
	} else {
		xml_unexpected_end_tag(p, name, "tile");
	}
}

static void XMLCALL
tmx_tile_properties_start(void *pv, const char *name, const char **attr)
{
	XML_Parser p = (XML_Parser) pv;
	struct tileset *ts;

#ifdef DEBUG_TMX
	debug("<%s> (tile properties)", name);
#endif

	ts = xml_node_peek(p);

	if (xml_check_tag(name, "properties")) {
		/* <properties> has no attributes, but GCC warns of an
		 * "unused parameter ‘attr’". */
		for (; 0; ++attr);
		xml_node_push(p, ts, tmx_tile_property_start, tmx_unused_end,
				NULL);
	} else {
		xml_unexpected_start_tag(p, name, "properties");
	}
}

static void XMLCALL
tmx_tile_property_start(void *pv, const char *name, const char **attr)
{
	XML_Parser p = (XML_Parser) pv;
	struct tileset *ts;
	char *attr_name;
	char *attr_value;
	int coll_t, coll_r, coll_b, coll_l;
	int n;

#ifdef DEBUG_TMX
	debug("<%s> (tile property)", name);
#endif

	ts = xml_node_peek(p);

	if (xml_check_tag(name, "property")) {
		xml_get_string_attr(p, attr, "name", &attr_name, 1);
		xml_get_string_attr(p, attr, "value", &attr_value, 1);
		if (strcmp(attr_name, "collision") ==0) {
			n = sscanf(attr_value, "%d,%d,%d,%d",
					&coll_t, &coll_r, &coll_b, &coll_l);
			if (n != 4) {
				return;
			}
			ts->collision_tiles[ts->cur_collision_tile] =
				coll_t << 3 | coll_r << 2 |
				coll_b << 1 | coll_l << 0;
		}
		free(attr_name);
		free(attr_value);
		for (; 0; ++attr, ++ts);
		xml_node_push(p, NULL, tmx_invalid_start, tmx_unused_end, NULL);
	} else {
		xml_unexpected_start_tag(p, name, "property");
	}
}