/*
 * Copyright (C) 2016, 2017, 2018 "IoT.bzh"
 * Author José Bollo <jose.bollo@iot.bzh>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * This simple program expands the object { "$ref": "#/path/to/a/target" }
 *
 * For example:
 *
 *  {
 *    "type":{
 *      "a": "int",
 *      "b": { "$ref": "#/type/a" }
 *    }
 *  }
 *
 * will be exapanded to
 *
 *  {
 *    "type":{
 *      "a": "int",
 *      "b": "int"
 *    }
 *  }
 *
 * Invocation:   program  [file|-]...
 *
 * without arguments, it reads the input.
 */

#define _GNU_SOURCE
#include <string.h>
#include <stdio.h>
#include <unistd.h>

#include <json-c/json.h>

#include "exprefs.h"

/**
 * process a file and prints its expansion on stdout
 */
void process(char *filename)
{
	struct json_object *root;

	/* translate - */
	if (!strcmp(filename, "-"))
		filename = "/dev/stdin";

	/* check access */
	if (access(filename, R_OK)) {
		fprintf(stderr, "can't access file %s\n", filename);
		exit(1);
	}

	/* read the file */
	root = json_object_from_file(filename);
	if (!root) {
		fprintf(stderr, "reading file %s produced null\n", filename);
		exit(1);
	}

	/* expand */
	root = exp$refs(root);

	/* check if tree */
	if (!exp$refs_is_tree(root)) {
		fprintf(stderr, "expansion of %s doesn't produce a tree\n", filename);
		exit(1);
	}

	/* print the result */
	json_object_to_file_ext ("/dev/stdout", root, JSON_C_TO_STRING_PRETTY);

	/* clean up */
	json_object_put(root);
}

/** process the list of files or stdin if none */
int main(int ac, char **av)
{
	if (!*++av)
		process("-");
	else {
		do { process(*av); } while(*++av);
	}
	return 0;
}