#include <cjson/cJSON.h>
#include <libguile.h>

#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

static SCM json_type;

static inline void assert_json (SCM item)
	{ scm_assert_foreign_object_type (json_type, item); }
static inline cJSON* to_json (SCM item)
	{ return scm_foreign_object_ref (item, 0); }
static inline SCM from_json (cJSON* item)
	{ return scm_make_foreign_object_1 (json_type, item); }

SCM_DEFINE (parse_json, "parse-json", 1, 0, 0,
		(SCM filename),
		"")
{
	char* fname = scm_to_utf8_stringn (filename, NULL);

	int fd = open(fname, O_RDONLY);
	struct stat sb;
	fstat(fd, &sb);
	const char* buf = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);

	return from_json (cJSON_Parse(buf));
}

SCM json_to_scheme (cJSON* j) {
	cJSON* node;
	switch (j->type) {
		case cJSON_Invalid:
			return scm_from_utf8_symbol("invalid");

		case cJSON_False:
			return SCM_BOOL_F;

		case cJSON_True:
			return SCM_BOOL_T;

		case cJSON_NULL:
			return SCM_EOL;

		case cJSON_Number:
			return scm_values(scm_list_2(
						scm_from_int(j->valueint),
						scm_from_double(j->valuedouble)));

		case cJSON_String:
			return scm_from_utf8_string(j->valuestring);

		case cJSON_Array:
			node = j->child;

			SCM list = SCM_EOL;
			while (node != NULL) {
				list = scm_cons(json_to_scheme(node), list);
				node = node->next;
			}
			return scm_vector(scm_reverse_x (list, SCM_EOL));

		case cJSON_Object:
			node = j->child;
			SCM table = scm_c_eval_string ("(make-hash-table)");
			while (node->next != NULL) {
				scm_hashq_set_x (table,
						scm_from_utf8_symbol(node->string),
						json_to_scheme(node));
				node = node->next;
			}
			return table;


		case cJSON_Raw:
			return scm_from_utf8_symbol("raw");
	}

	return scm_from_utf8_symbol("nocase");
}

SCM_DEFINE(json_to_scheme_, "json->scm", 1, 0, 0,
		(SCM json),
		"")
{
	assert_json(json);
	cJSON* j = to_json(json);

	return json_to_scheme (j);
}

static void finilize_json (SCM json) {
	cJSON* j = to_json(json);
	cJSON_Delete (j);
}

static void init_json_type (void) {
	SCM name = scm_from_utf8_symbol("json");
	SCM slot = scm_list_1(scm_from_utf8_symbol("data"));
	scm_t_struct_finalize finilizer = finilize_json;;
	json_type = scm_make_foreign_object_type (name, slot, finilizer);
}

void init_json (void) {
	init_json_type ();

#ifndef SCM_MAGIC_SNARFER
#include "json.x"
#endif
}