#include <stdio.h>
#include <string.h>
#include <libgen.h>
#include <ctype.h>
#include <expat.h>
#include "map.h"
#include "resource.h"
#include "../xml.h"
#include "../logging.h"

struct resource_table ts_res;
struct resource_table map_res;

static struct tileset *tileset_get(const char *, const char *);
static void XMLCALL tmx_map_start(void *, const char *, const char **);
static void XMLCALL tmx_map_end(void *, const char *);
static void XMLCALL tmx_map_el_start(void *, const char *, const char **);
static void XMLCALL tmx_tileset_start(void *, const char *, const char **);
static void XMLCALL tmx_tileset_end(void *, const char *);
static void XMLCALL tmx_tilesheetemb_end(void *, const char *);
static void XMLCALL tmx_tileset_el_start(void *, const char *, const char **);
static void XMLCALL tmx_image_end(void *, const char *);
static void XMLCALL tmx_unused_start(void *, const char *, const char **);
static void XMLCALL tmx_unused_end(void *, const char *);
static void XMLCALL tmx_invalid_start(void *, const char *, const char **);
static void XMLCALL tmx_invalid_end(void *, const char *);

struct map *
map_get(const char *path)
{
	struct map *map;
	XML_Parser p;
	FILE *tmx_fp;
	void *tmx_buf;
	size_t len;
	enum XML_Status status;

	map = (struct map *) resource_get(&map_res, path);
	if (map != NULL) {
		resource_use((struct resource *) map);
		return map;
	}

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

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

	XML_UseParserAsHandlerArg(p);
	xml_node_push(p, map, tmx_map_start, tmx_invalid_end, NULL);

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

	tmx_buf = XML_GetBuffer(p, 8192);
	if (tmx_buf == NULL) {
		warn("Failed to create TMX 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 TMX 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 *) map);
	resource_add(&map_res, path, (struct resource *) map);

	return map;
}

void
map_add_layer(struct map *m, struct layer *l)
{
	if (m->layers_head == NULL) {
		m->layers_head = l;
	} else {
		m->layers_tail->next = l;
	}
	m->layers_tail = l;
}

void
map_add_tileset(struct map *m, struct tileset *t)
{
	if (m->tilesets_head == NULL) {
		m->tilesets_head = t;
	} else {
		m->tilesets_tail->next = t;
	}
	m->tilesets_tail = t;
}

static 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;
}

static void XMLCALL
tmx_map_start(void *pv, const char *name, const char **attr)
{
	XML_Parser p = (XML_Parser) pv;
	struct map *m;

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

	if (xml_check_tag(name, "map")) {
		m = xml_node_peek(p);
		xml_get_int_attr(p, attr, "width", &m->width, 1);
		xml_get_int_attr(p, attr, "height", &m->height, 1);
		xml_get_int_attr(p, attr, "tilewidth", &m->tilewidth, 1);
		xml_get_int_attr(p, attr, "tileheight", &m->tileheight, 1);
		xml_node_push(p, m, tmx_map_el_start, tmx_map_end, NULL);
	} else {
		xml_unexpected_start_tag(p, name, "map");
	}
}

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

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

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

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

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

	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, "tileset")) {
		dirname = ((struct map *) xml_node_peek(p))->dirname;
		source = NULL;
		xml_get_string_attr(p, attr, "source", &source, 0);
		if (source != NULL) {
			/* External tilesheet. */
			path = malloc(strlen(dirname) + strlen(source) + 2);
			if (path == NULL) {
				return;
			}
			sprintf(path, "%s/%s", dirname, source);
			ts = tileset_get(path, dirname);
			free(source);
			xml_node_push(p, ts, tmx_invalid_start,
					tmx_tilesheetemb_end, NULL);
		} else {
			/* Embedded tilesheet. */
			ts = resource_alloc("internal", sizeof(*ts));
			if (ts == NULL) {
				return;
			}
			ts->dirname = dirname;
			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);
			xml_node_push(p, ts, tmx_tileset_el_start,
					tmx_tilesheetemb_end, NULL);
		}
		xml_get_int_attr(p, attr, "firstgid", &ts->firstgid, 1);
	} else {
		xml_unexpected_start_tag(p, name,
				"properties, tileset, layer, or objectgroup");
	}
}

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

	debug("<%s> (tileset)", name);

	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);
		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;

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

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

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

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

	if (xml_check_tag(name, "tileset")) {
		ts = (struct tileset *) xml_node_pop(p);
		map_add_tileset((struct map *) xml_node_peek(p), ts);
	} else {
		xml_unexpected_end_tag(p, name, "tileset");
	}
}

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

	debug("<%s> (tileset child)", name);

	if (xml_check_tag(name, "image")) {
		dirname = ((struct tileset *) xml_node_peek(p))->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);
		free(source);
		xml_node_push(p, img, tmx_invalid_start, tmx_image_end, NULL);
	} else {
		xml_unexpected_start_tag(p, name, "image");
	}
}

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

	debug("</%s> (image)", name);

	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_unused_start(void *pv, const char *name, const char **attr)
{
	XML_Parser p = (XML_Parser) pv;

	debug("<%s> (unused)", name);

	/* Shut up, GCC. */
	for (; *name != '\0'; ++name);
	for (; *attr != NULL; ++attr);

	xml_node_push(p, NULL, tmx_unused_start, tmx_unused_end, NULL);
}

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

	debug("<%s> (unused)", name);

	/* Shut up, GCC. */
	for (; *name != '\0'; ++name);

	xml_node_pop(p);
}

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

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

	/* Shut up, GCC. */
	for (; *attr != NULL; ++attr);

	xml_unexpected_start_tag(p, name, "");
}

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

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

	xml_unexpected_end_tag(p, name, "");
}