/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0.  If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

/*! \file
 */

#include <stdbool.h>
#include <stdlib.h>
#include <string.h>

#include <isc/app.h>
#include <isc/commandline.h>
#include <isc/hash.h>
#include <isc/managers.h>
#include <isc/netaddr.h>
#include <isc/print.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/util.h>

#include <dns/adb.h>
#include <dns/cache.h>
#include <dns/dispatch.h>
#include <dns/events.h>
#include <dns/forward.h>
#include <dns/log.h>
#include <dns/resolver.h>
#include <dns/result.h>

static isc_mem_t *mctx = NULL;
static isc_nm_t *netmgr = NULL;
static isc_taskmgr_t *taskmgr = NULL;
static dns_view_t *view = NULL;
static dns_adbfind_t *find = NULL;
static isc_task_t *task = NULL;
static dns_fixedname_t fixed;
static dns_fixedname_t target;
static isc_log_t *lctx = NULL;
static isc_logconfig_t *lcfg = NULL;
static unsigned int level = 0;

static void
adb_callback(isc_task_t *task, isc_event_t *event);

static void
log_init(void) {
	isc_logdestination_t destination;
	unsigned int flags;

	/*
	 * Setup a logging context.
	 */
	isc_log_create(mctx, &lctx, &lcfg);
	isc_log_setcontext(lctx);
	dns_log_init(lctx);
	dns_log_setcontext(lctx);

	/*
	 * Create and install the default channel.
	 */
	destination.file.stream = stderr;
	destination.file.name = NULL;
	destination.file.versions = ISC_LOG_ROLLNEVER;
	destination.file.maximum_size = 0;
	flags = ISC_LOG_PRINTTIME;
	isc_log_createchannel(lcfg, "_default", ISC_LOG_TOFILEDESC,
			      ISC_LOG_DYNAMIC, &destination, flags);

	RUNTIME_CHECK(isc_log_usechannel(lcfg, "_default", NULL, NULL) ==
		      ISC_R_SUCCESS);
	isc_log_setdebuglevel(lctx, level);
}

static void
print_addresses(dns_adbfind_t *adbfind) {
	dns_adbaddrinfo_t *address;

	for (address = ISC_LIST_HEAD(adbfind->list); address != NULL;
	     address = ISC_LIST_NEXT(address, publink))
	{
		isc_netaddr_t netaddr;
		char text[ISC_NETADDR_FORMATSIZE];
		isc_netaddr_fromsockaddr(&netaddr, &address->sockaddr);
		isc_netaddr_format(&netaddr, text, sizeof(text));
		printf("%s\n", text);
	}
}

static void
print_name(dns_name_t *name) {
	char text[DNS_NAME_FORMATSIZE];

	dns_name_format(name, text, sizeof(text));
	printf("%s\n", text);
}

static void
do_find(bool want_event) {
	isc_result_t result;
	bool done = false;
	unsigned int options;

	options = DNS_ADBFIND_INET | DNS_ADBFIND_INET6;
	if (want_event) {
		options |= DNS_ADBFIND_WANTEVENT | DNS_ADBFIND_EMPTYEVENT;
	}
	dns_fixedname_init(&target);
	result = dns_adb_createfind(view->adb, task, adb_callback, NULL,
				    dns_fixedname_name(&fixed), dns_rootname, 0,
				    options, 0, dns_fixedname_name(&target), 0,
				    0, NULL, &find);
	if (result == ISC_R_SUCCESS) {
		if (!ISC_LIST_EMPTY(find->list)) {
			/*
			 * We have at least some of the addresses for the
			 * name.
			 */
			INSIST((find->options & DNS_ADBFIND_WANTEVENT) == 0);
			print_addresses(find);
			done = true;
		} else {
			/*
			 * We don't know any of the addresses for this
			 * name.
			 */
			if ((find->options & DNS_ADBFIND_WANTEVENT) == 0) {
				/*
				 * And ADB isn't going to send us any events
				 * either.  This query loses.
				 */
				done = true;
			}
			/*
			 * If the DNS_ADBFIND_WANTEVENT flag was set, we'll
			 * get an event when something happens.
			 */
		}
	} else if (result == DNS_R_ALIAS) {
		print_name(dns_fixedname_name(&target));
		done = true;
	} else {
		printf("dns_adb_createfind() returned %s\n",
		       isc_result_totext(result));
		done = true;
	}

	if (done) {
		if (find != NULL) {
			dns_adb_destroyfind(&find);
		}
		isc_app_shutdown();
	}
}

static void
adb_callback(isc_task_t *etask, isc_event_t *event) {
	unsigned int type = event->ev_type;

	REQUIRE(etask == task);

	isc_event_free(&event);
	dns_adb_destroyfind(&find);

	if (type == DNS_EVENT_ADBMOREADDRESSES) {
		do_find(false);
	} else if (type == DNS_EVENT_ADBNOMOREADDRESSES) {
		printf("no more addresses\n");
		isc_app_shutdown();
	} else {
		printf("unexpected ADB event type %u\n", type);
		isc_app_shutdown();
	}
}

static void
run(isc_task_t *xtask, isc_event_t *event) {
	UNUSED(xtask);
	do_find(true);
	isc_event_free(&event);
}

int
main(int argc, char *argv[]) {
	bool verbose = false;
	unsigned int workers = 2;
	isc_timermgr_t *timermgr = NULL;
	int ch;
	isc_socketmgr_t *socketmgr = NULL;
	dns_dispatchmgr_t *dispatchmgr = NULL;
	dns_cache_t *cache = NULL;
	isc_buffer_t b;

	RUNTIME_CHECK(isc_app_start() == ISC_R_SUCCESS);

	dns_result_register();

	isc_mem_create(&mctx);

	while ((ch = isc_commandline_parse(argc, argv, "d:vw:")) != -1) {
		switch (ch) {
		case 'd':
			level = (unsigned int)atoi(isc_commandline_argument);
			break;
		case 'v':
			verbose = true;
			break;
		case 'w':
			workers = (unsigned int)atoi(isc_commandline_argument);
			break;
		}
	}

	log_init();

	if (verbose) {
		printf("%u workers\n", workers);
		printf("IPv4: %s\n", isc_result_totext(isc_net_probeipv4()));
		printf("IPv6: %s\n", isc_result_totext(isc_net_probeipv6()));
	}

	RUNTIME_CHECK(isc_managers_create(mctx, workers, 0, &netmgr,
					  &taskmgr) == ISC_R_SUCCESS);
	RUNTIME_CHECK(isc_task_create(taskmgr, 0, &task) == ISC_R_SUCCESS);
	isc_task_setname(task, "byname", NULL);

	RUNTIME_CHECK(dns_dispatchmgr_create(mctx, &dispatchmgr) ==
		      ISC_R_SUCCESS);

	RUNTIME_CHECK(isc_timermgr_create(mctx, &timermgr) == ISC_R_SUCCESS);
	RUNTIME_CHECK(isc_socketmgr_create(mctx, &socketmgr) == ISC_R_SUCCESS);

	RUNTIME_CHECK(dns_cache_create(mctx, mctx, taskmgr, timermgr,
				       dns_rdataclass_in, "", "rbt", 0, NULL,
				       &cache) == ISC_R_SUCCESS);

	RUNTIME_CHECK(dns_view_create(mctx, dns_rdataclass_in, "default",
				      &view) == ISC_R_SUCCESS);

	{
		unsigned int attrs;
		dns_dispatch_t *disp4 = NULL;
		dns_dispatch_t *disp6 = NULL;

		if (isc_net_probeipv4() == ISC_R_SUCCESS) {
			isc_sockaddr_t any4;
			isc_sockaddr_any(&any4);

			attrs = DNS_DISPATCHATTR_IPV4 | DNS_DISPATCHATTR_UDP;
			RUNTIME_CHECK(
				dns_dispatch_getudp(dispatchmgr, socketmgr,
						    taskmgr, &any4, 512, 6,
						    1024, 17, 19, attrs, attrs,
						    &disp4) == ISC_R_SUCCESS);
			INSIST(disp4 != NULL);
		}

		if (isc_net_probeipv6() == ISC_R_SUCCESS) {
			isc_sockaddr_t any6;

			isc_sockaddr_any6(&any6);

			attrs = DNS_DISPATCHATTR_IPV6 | DNS_DISPATCHATTR_UDP;
			RUNTIME_CHECK(
				dns_dispatch_getudp(dispatchmgr, socketmgr,
						    taskmgr, &any6, 512, 6,
						    1024, 17, 19, attrs, attrs,
						    &disp6) == ISC_R_SUCCESS);
			INSIST(disp6 != NULL);
		}

		RUNTIME_CHECK(dns_view_createresolver(view, taskmgr, 10, 1,
						      socketmgr, timermgr, 0,
						      dispatchmgr, disp4,
						      disp6) == ISC_R_SUCCESS);

		if (disp4 != NULL) {
			dns_dispatch_detach(&disp4);
		}
		if (disp6 != NULL) {
			dns_dispatch_detach(&disp6);
		}
	}

	{
		struct in_addr ina;
		isc_sockaddr_t sa;
		isc_sockaddrlist_t sal;

		ISC_LIST_INIT(sal);
		ina.s_addr = inet_addr("127.0.0.1");
		isc_sockaddr_fromin(&sa, &ina, 53);
		ISC_LIST_APPEND(sal, &sa, link);

		REQUIRE(DNS_VIEW_VALID(view));
		RUNTIME_CHECK(dns_fwdtable_add(view->fwdtable, dns_rootname,
					       &sal, dns_fwdpolicy_only) ==
			      ISC_R_SUCCESS);
	}

	dns_view_setcache(view, cache, false);
	dns_view_freeze(view);

	dns_cache_detach(&cache);

	printf("name = %s\n", argv[isc_commandline_index]);
	isc_buffer_init(&b, argv[isc_commandline_index],
			strlen(argv[isc_commandline_index]));
	isc_buffer_add(&b, strlen(argv[isc_commandline_index]));
	dns_fixedname_init(&fixed);
	dns_fixedname_init(&target);
	RUNTIME_CHECK(dns_name_fromtext(dns_fixedname_name(&fixed), &b,
					dns_rootname, 0,
					NULL) == ISC_R_SUCCESS);

	RUNTIME_CHECK(isc_app_onrun(mctx, task, run, NULL) == ISC_R_SUCCESS);

	(void)isc_app_run();

	dns_view_detach(&view);
	isc_task_shutdown(task);
	isc_task_detach(&task);

	dns_dispatchmgr_destroy(&dispatchmgr);

	isc_managers_destroy(&netmgr, &taskmgr);

	isc_socketmgr_destroy(&socketmgr);
	isc_timermgr_destroy(&timermgr);

	isc_log_destroy(&lctx);

	if (verbose) {
		isc_mem_stats(mctx, stdout);
	}
	isc_mem_destroy(&mctx);

	isc_app_finish();

	return (0);
}