/* MiniDLNA media server
 * Copyright (C) 2017  NETGEAR
 *
 * This file is part of MiniDLNA.
 *
 * MiniDLNA is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * MiniDLNA is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MiniDLNA. If not, see <http://www.gnu.org/licenses/>.
 */

/* This file is loosely based on examples from zeroconf_avahi_demos:
 * http://wiki.ros.org/zeroconf_avahi_demos
 * with some ideas from Netatalk's Avahi implementation.
 */

#include <config.h>

#if defined(TIVO_SUPPORT) && defined(HAVE_AVAHI)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include <time.h>

#include <avahi-common/error.h>
#include <avahi-common/thread-watch.h>
#include <avahi-client/publish.h>

#include "upnpglobalvars.h"
#include "log.h"

static struct context {
	AvahiThreadedPoll *threaded_poll;
	AvahiClient       *client;
	AvahiEntryGroup   *group;
} ctx;

/*****************************************************************
 * Private functions
 *****************************************************************/

/* Called when publishing of service data completes */
static void publish_reply(AvahiEntryGroup *g,
			  AvahiEntryGroupState state,
			  AVAHI_GCC_UNUSED void *userdata)
{
	assert(ctx.group == NULL || g == ctx.group);

	switch (state) {
	case AVAHI_ENTRY_GROUP_ESTABLISHED:
		/* The entry group has been established successfully */
		DPRINTF(E_MAXDEBUG, L_SSDP, "publish_reply: AVAHI_ENTRY_GROUP_ESTABLISHED\n");
		break;
	case AVAHI_ENTRY_GROUP_COLLISION:
		/* With multiple names there's no way to know which one collided */
		DPRINTF(E_ERROR, L_SSDP, "publish_reply: AVAHI_ENTRY_GROUP_COLLISION: %s\n",
				avahi_strerror(avahi_client_errno(ctx.client)));
		avahi_threaded_poll_quit(ctx.threaded_poll);
		break;
	case AVAHI_ENTRY_GROUP_FAILURE:
		DPRINTF(E_ERROR, L_SSDP, "Failed to register service: %s\n",
				avahi_strerror(avahi_client_errno(ctx.client)));
		avahi_threaded_poll_quit(ctx.threaded_poll);
		break;
	case AVAHI_ENTRY_GROUP_UNCOMMITED:
	case AVAHI_ENTRY_GROUP_REGISTERING:
	default:
		break;
	}
}

static int
_add_svc(const char *cat, const char *srv, const char *id, const char *platform)
{
	char name[128+1];
	char path[64];
	int ret;

	snprintf(name, sizeof(name), "%s on %s", cat, friendly_name);
	snprintf(path, sizeof(path),
		 "path=/TiVoConnect?Command=QueryContainer&Container=%s", id);

	DPRINTF(E_INFO, L_SSDP, "Registering '%s'\n", name);
	ret = avahi_entry_group_add_service(ctx.group, AVAHI_IF_UNSPEC, AVAHI_PROTO_INET,
					    0, name, srv, NULL, NULL, runtime_vars.port,
					    "protocol=http", path, platform, NULL);
	if (ret < 0)
		DPRINTF(E_ERROR, L_SSDP, "Failed to add %s: %s\n",
			srv, avahi_strerror(avahi_client_errno(ctx.client)));

	return ret;
}

/* Try to register the TiVo DNS SRV service type. */
static void
register_stuff(void)
{
	assert(ctx.client);

	if (!ctx.group)
	{
		ctx.group = avahi_entry_group_new(ctx.client, publish_reply, NULL);
		if (!ctx.group)
		{
			DPRINTF(E_ERROR, L_SSDP, "Failed to create entry group: %s\n",
				avahi_strerror(avahi_client_errno(ctx.client)));
			return;
		}
	}

	if (avahi_entry_group_is_empty(ctx.group))
	{
		if (_add_svc("Music", "_tivo-music._tcp", "1", NULL) < 0)
			return;
		if (_add_svc("Photos", "_tivo-photos._tcp", "3", NULL) < 0)
			return;
		if (_add_svc("Videos", "_tivo-videostream._tcp", "2", "platform=pc/"SERVER_NAME) < 0)
			return;
		if (avahi_entry_group_commit(ctx.group) < 0)
		{
			DPRINTF(E_ERROR, L_SSDP, "Failed to commit entry group: %s\n",
				avahi_strerror(avahi_client_errno(ctx.client)));
			return;
		}
	}
}

static void client_callback(AvahiClient *client,
			    AvahiClientState state,
			    void *userdata)
{
	ctx.client = client;

	switch (state) {
	case AVAHI_CLIENT_S_RUNNING:
		/* The server has started up successfully and registered its host
		* name on the network, so it's time to create our services */
		register_stuff();
		break;
	case AVAHI_CLIENT_S_COLLISION:
	case AVAHI_CLIENT_S_REGISTERING:
		if (ctx.group)
			avahi_entry_group_reset(ctx.group);
		break;
	case AVAHI_CLIENT_FAILURE:
		if (avahi_client_errno(client) == AVAHI_ERR_DISCONNECTED)
		{
			int error;

			avahi_client_free(ctx.client);
			ctx.client = NULL;
			ctx.group = NULL;

			/* Reconnect to the server */
			ctx.client = avahi_client_new(
					avahi_threaded_poll_get(ctx.threaded_poll),
					AVAHI_CLIENT_NO_FAIL, client_callback,
					&ctx, &error);
			if (!ctx.client)
			{
				DPRINTF(E_ERROR, L_SSDP,
					"Failed to contact server: %s\n",
					avahi_strerror(error));
				avahi_threaded_poll_quit(ctx.threaded_poll);
			}
		}
		else
		{
			DPRINTF(E_ERROR, L_SSDP, "Client failure: %s\n",
				avahi_strerror(avahi_client_errno(client)));
			avahi_threaded_poll_quit(ctx.threaded_poll);
		}
		break;
	case AVAHI_CLIENT_CONNECTING:
	default:
		break;
	}
}

/************************************************************************
 * Public funcions
 ************************************************************************/

/*
 * Tries to shutdown this loop impl.
 * Call this function from inside this thread.
 */
void tivo_bonjour_unregister(void)
{
	DPRINTF(E_DEBUG, L_SSDP, "tivo_bonjour_unregister\n");

	if (ctx.group)
	{
		avahi_entry_group_reset(ctx.group);
		avahi_entry_group_free(ctx.group);
	}
	if (ctx.threaded_poll)
		avahi_threaded_poll_stop(ctx.threaded_poll);
	if (ctx.client)
		avahi_client_free(ctx.client);
	if (ctx.threaded_poll)
		avahi_threaded_poll_free(ctx.threaded_poll);
}

/*
 * Tries to setup the Zeroconf thread and any
 * neccessary config setting.
 */
void tivo_bonjour_register(void)
{
	int error;

	/* first of all we need to initialize our threading env */
	ctx.threaded_poll = avahi_threaded_poll_new();
	if (!ctx.threaded_poll)
		return;

	/* now we need to acquire a client */
	ctx.client = avahi_client_new(avahi_threaded_poll_get(ctx.threaded_poll),
			AVAHI_CLIENT_NO_FAIL, client_callback, NULL, &error);
	if (!ctx.client)
	{
		DPRINTF(E_ERROR, L_SSDP, "Failed to create client object: %s\n",
					avahi_strerror(error));
		tivo_bonjour_unregister();
		return;
	}

	if (avahi_threaded_poll_start(ctx.threaded_poll) < 0)
	{
		DPRINTF(E_ERROR, L_SSDP, "Failed to create thread: %s\n",
					avahi_strerror(avahi_client_errno(ctx.client)));
		tivo_bonjour_unregister();
	}
	else
		DPRINTF(E_INFO, L_SSDP, "Successfully started avahi loop\n");
}
#endif /* HAVE_AVAHI */