/*
 * ldnssec-utils
 *
 * Written in 2021 by Lucas
 *
 * To the extent possible under law, the author(s) have dedicated all
 * copyright and related and neighboring rights to this software to the
 * public domain worldwide. This software is distributed without any
 * warranty.
 *
 * You should have received a copy of the CC0 Public Domain Dedication
 * along with this software. If not, see
 * <http://creativecommons.org/publicdomain/zero/1.0/>.
 */

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <ldns/ldns.h>

#include "util.h"

#define DEFAULT_DURATION	(30 * 86400) /* 30 days */

static int
extend_key_from_zone(ldns_key *k, const ldns_zone *z)
{
	ldns_rr_list *rrs;
	ldns_rr *soa, *key_rr;
	size_t i;
	int match = 0;

	soa = ldns_zone_soa(z);
	rrs = ldns_zone_rrs(z);
	key_rr = ldns_key2rr(k);
	if (key_rr == NULL)
		errx(1, "ldns_key2rr");
	for (i = 0; i < ldns_rr_list_rr_count(rrs); i++) {
		ldns_rr *rr;
		ldns_rdf *owner_rdf;

		rr = ldns_rr_list_rr(rrs, i);
		if (ldns_rr_get_type(rr) != LDNS_RR_TYPE_DNSKEY ||
		    ldns_rdf_compare(ldns_rr_dnskey_protocol(rr),
		    ldns_rr_dnskey_protocol(key_rr)) != 0 ||
		    ldns_rdf_compare(ldns_rr_dnskey_algorithm(rr),
		    ldns_rr_dnskey_algorithm(key_rr)) != 0 ||
		    ldns_rdf_compare(ldns_rr_dnskey_key(rr),
		    ldns_rr_dnskey_key(key_rr)) != 0)
			continue;

		/* key and DNSKEY have the same pubkey and algorithm */
		owner_rdf = ldns_rdf_clone(ldns_rr_owner(rr));
		if (owner_rdf == NULL)
			errx(1, "ldns_rdf_clone");
		ldns_key_set_pubkey_owner(k, owner_rdf);
		ldns_key_set_origttl(k, ldns_rr_ttl(rr));
		ldns_key_set_keytag(k, ldns_calc_keytag(rr));
		ldns_key_set_flags(k,
		    ldns_rdf2native_int16(ldns_rr_dnskey_flags(rr)));
		match = 1;
		break;
	}
	ldns_rr_free(key_rr);

	return match;
}

static int
parse_datetime(const char *buf, struct tm *tm)
{
	char *s;
	time_t t;

	t = time(NULL);
	if (t == (time_t)-1)
		err(1, "time");
	if (gmtime_r(&t, tm) == NULL)
		errx(1, "gmtime_r");

	/* attempt to parse as YYYYMMDDhhmmss */
	s = strptime(buf, "%Y %m %d %H %M %S", tm);
	if (s != NULL && *s == '\0')
		return 1;

	/* failed; attemp to parse as YYYYMMDD */
	s = strptime(buf, "%Y %m %d", tm);
	if (s != NULL && *s == '\0')
		return 1;

	return 0;
}

static void
usage(void)
{
	const char *p = getprogname();

	fprintf(stderr, "Usage:\n"
	    "\t%s [-d duration] [-i inception] key [key ...]\n"
	    "\t%s [-e expiration] [-i inception] key [key ...]\n",
	    p, p);
	exit(1);
}

int
main(int argc, char *argv[])
{
	ldns_zone *zone = NULL;
	ldns_dnssec_zone *dnssec_zone;
	ldns_key_list *keys;
	ldns_rr_list *added_rrs, *origin_rrs;
	ldns_rr *origin_soa;
	ldns_status s;
	const char *errstr;
	struct tm tm;
	time_t t;
	size_t i;
	long long n;
	uint32_t expiration, inception, duration;
	int ch, line_nr;
	int dflag, eflag, iflag;

	dflag = eflag = iflag = 0;
	duration = DEFAULT_DURATION;
	while ((ch = getopt(argc, argv, "d:e:i:")) != -1) {
		switch (ch) {
		case 'd':
			dflag = 1;
			n = strtonum(optarg, 0, UINT32_MAX, &errstr);
			if (errstr != NULL)
				errx(1, "-d: duration is %s: %s", errstr,
				    optarg);
			duration = n;
			break;
		case 'e':
			eflag = 1;
			if (!parse_datetime(optarg, &tm))
				errx(1, "-e: not in YYYYMMDDhhmmss or "
				    "YYYYMMDD format");
			t = mktime(&tm);
			if (t == (time_t)-1)
				errx(1, "mktime");
			expiration = t & 0xffffffff;
			break;
		case 'i':
			iflag = 1;
			if (!parse_datetime(optarg, &tm))
				errx(1, "-i: not in YYYYMMDDhhmmss or "
				    "YYYYMMDD format");
			t = mktime(&tm);
			if (t == (time_t)-1)
				errx(1, "mktime");
			inception = t & 0xffffffff;
			break;
		default:
			usage();
		}
	}
	argc -= optind;
	argv += optind;

	if (dflag && eflag)
		errx(1, "-d and -e are mutually exclusive");
	if (argc == 0)
		usage();

	if (!iflag) {
		t = time(NULL);
		if (t == (time_t)-1)
			err(1, "time");
		inception = t & 0xffffffff;
	}
	if (!eflag)
		expiration = inception + duration;

	fatal_check_minimum_ldns_revision();

	s = ldns_zone_new_frm_fp_l(&zone, stdin, NULL, LDNS_DEFAULT_TTL,
	    LDNS_RR_CLASS_IN, &line_nr);
	if (s != LDNS_STATUS_OK)
		errx(1, "ldns_zone_new_frm_fp_l: (stdin) line %d: %s",
		    line_nr, ldns_get_errorstr_by_id(s));

	origin_soa = ldns_zone_soa(zone);
	if (origin_soa == NULL)
		errx(1, "no SOA in zone");
	origin_rrs = ldns_zone_rrs(zone);

	dnssec_zone = ldns_dnssec_zone_new();
	if (dnssec_zone == NULL)
		err(1, "ldns_dnssec_zone_new");
	s = ldns_dnssec_zone_add_rr(dnssec_zone, origin_soa);
	if (s != LDNS_STATUS_OK)
		errx(1, "ldns_dnssec_zone_add_rr: %s",
		    ldns_get_errorstr_by_id(s));
	for (i = 0; i < ldns_rr_list_rr_count(origin_rrs); i++) {
		ldns_rr *rr;

		rr = ldns_rr_list_rr(origin_rrs, i);
		if (ldns_rr_get_type(rr) != LDNS_RR_TYPE_DNSKEY ||
		    ldns_rdf_compare(ldns_rr_owner(rr),
		    ldns_rr_owner(origin_soa)) != 0)
			continue;

		s = ldns_dnssec_zone_add_rr(dnssec_zone, rr);
		if (s != LDNS_STATUS_OK)
			errx(1, "ldns_dnssec_zone_add_rr: %s",
			    ldns_get_errorstr_by_id(s));
	}

	keys = ldns_key_list_new();
	if (keys == NULL)
		err(1, "ldns_key_list_new");
	for (; *argv != NULL; argv++) {
		ldns_key *k = NULL;
		FILE *fp;

		fp = fopen(*argv, "r");
		if (fp == NULL)
			err(1, "fopen: %s", *argv);
		s = ldns_key_new_frm_fp_l(&k, fp, &line_nr);
		(void)fclose(fp);
		if (s != LDNS_STATUS_OK)
			errx(1, "ldns_key_new_frm_fp_l: %s line %d: %s",
			    *argv, line_nr, ldns_get_errorstr_by_id(s));

		if (!extend_key_from_zone(k, zone))
			errx(1, "no DNSKEY in zone for private key \"%s\"",
			    *argv);
		ldns_key_set_expiration(k, expiration);
		ldns_key_set_inception(k, inception);

		if (!ldns_key_list_push_key(keys, k))
			err(1, "ldns_key_list_push_key");
	}

	added_rrs = ldns_rr_list_new();
	if (added_rrs == NULL)
		err(1, "ldns_rr_list_new");
	s = ldns_dnssec_zone_create_rrsigs_flg(dnssec_zone, added_rrs, keys,
	    ldns_dnssec_default_replace_signatures, NULL, 0);
	if (s != LDNS_STATUS_OK)
		errx(1, "ldns_dnssec_zone_create_rrsigs_flg: %s",
		    ldns_get_errorstr_by_id(s));

	for (i = 0; i < ldns_rr_list_rr_count(added_rrs); i++) {
		ldns_rr *rr;
		char *str;

		rr = ldns_rr_list_rr(added_rrs, i);
		if (ldns_rr_get_type(rr) != LDNS_RR_TYPE_RRSIG ||
		    ldns_rdf2native_int16(ldns_rr_rrsig_typecovered(rr)) !=
		    LDNS_RR_TYPE_DNSKEY)
			continue;

		str = ldns_rr2str(rr);
		if (str == NULL)
			errx(1, "ldns_rr2str");
		fputs(str, stdout);
		free(str);
	}

	ldns_key_list_free(keys);
	ldns_dnssec_zone_free(dnssec_zone);
	ldns_zone_deep_free(zone);
	ldns_rr_list_deep_free(added_rrs);

	return 0;
}