#include <stdarg.h>
#include <stdio.h>
#include <json.h>

static bool append_printf(char **dest, int64_t *size, int64_t *index, const char *fmt, ...) {
	va_list ap;
	int64_t len;
	
	va_start(ap, fmt);
	len = vsnprintf(*dest + *index, *size - *index, fmt, ap);
	va_end(ap);

	if (*index + len >= *size) {
		*size = *size * 2 > *size + len + 1 ? *size * 2 : *size + len + 1;
		*dest = realloc(*dest, *size);

		va_start(ap, fmt);
		len = vsnprintf(*dest + *index, *size - *index, fmt, ap);
		va_end(ap);
	}

	// TODO: Fix this ugly cast
	if (len < 0 || len >= *size) {
		free(*dest);
		*dest = "";
		return false;
	}

	*index += len;

	return true;
}

void print_item(struct json *json, char **str, int64_t *size, int64_t *index) {
	switch (json->type) {
		case JSON_OBJECT:
			append_printf(str, size, index, "{");
			for (struct json *j = json->children->items[0]; j; j = j->next) {
				append_printf(str, size, index, "\"%s\":", j->key ? j->key : "(null)");
				print_item(j, str, size, index);
				if (j->next)
					append_printf(str, size, index, ",");
			}
			append_printf(str, size, index, "}");
			break;
		case JSON_ARRAY:
			append_printf(str, size, index, "[");
			for (size_t i = 0; i < json->children->nitems; i++) {
				struct json *j = json->children->items[i];
				print_item(j, str, size, index);
				if (i != json->children->nitems - 1)
					append_printf(str, size, index, ",");
			}
			append_printf(str, size, index, "]");
			break;
		case JSON_NUMBER:
			append_printf(str, size, index, "%lf", json->num);
			break;
		case JSON_TRUE:
			append_printf(str, size, index, "true");
			break;
		case JSON_FALSE:
			append_printf(str, size, index, "false");
			break;
		case JSON_NULL:
			append_printf(str, size, index, "null");
			break;
		case JSON_STRING:
			append_printf(str, size, index, "\"");
			for (char *ptr = json->string; *ptr != '\0'; ptr++) {
				switch (*ptr) {
					case '\\':
						append_printf(str, size, index, "%s", "\\\\");
						break;
					case '\"':
						append_printf(str, size, index, "%s", "\\\"");
						break;
					case '\n':
						append_printf(str, size, index, "%s", "\\n");
						break;
					case '\f':
						append_printf(str, size, index, "%s", "\\f");
						break;
					case '\b':
						append_printf(str, size, index, "%s", "\\b");
						break;
					case '\r':
						append_printf(str, size, index, "%s", "\\r");
						break;
					case '\t':
						append_printf(str, size, index, "%s", "\\t");
						break;
					default:
						append_printf(str, size, index, "%c", *ptr);
						break;
				}
			}
			append_printf(str, size, index, "\"");
			break;
		case JSON_INVALID:
			break;
	}
}

char *json_print(struct json *json) {
	int64_t size = 1024;
	int64_t index = 0;
	char *str = calloc(size, sizeof(char));
	print_item(json, &str, &size, &index);
	return str;
}