#include "rodisc.h"

#include <avahi-gobject/ga-client.h>
#include <avahi-gobject/ga-entry-group.h>

static GaClient *mdns_client;
static GaEntryGroup *mdns_group;
static GaEntryGroupService *mdns_service;

static guint disc_change_count = 0;

static void mdns_service_freeze()
{
	g_return_if_fail(mdns_service);
	ga_entry_group_service_freeze(mdns_service);
}

static void mdns_service_thaw()
{
	GError *error = NULL;
	g_return_if_fail(mdns_service);
	if (!ga_entry_group_service_thaw(mdns_service, &error)) {
		g_warning("Could not update service TXT entries: %s", error->message);
		g_error_free(error);
	}
}

static void mdns_service_update()
{
	GError *error = NULL;

	g_return_if_fail(mdns_service);

	// "sys=waMA=00:00:00:00:00:00,adVF=0x4,adDT=0x2,adCC=0"
	// waMA = MAC address
	// adVF = Volume flags (0x200 "ask me first")
	// adDT = Supported media?
	// adCC = Disc change count?

	guint flags = 0;
	guint media = 2;
	gchar *record =
	        g_strdup_printf("waMA=00:00:00:00:00:00,adVF=0x%x,adDT=0x%x,adCC=%u",
	                        flags, media, disc_change_count);

	if (!ga_entry_group_service_set(mdns_service, "sys", record, &error))
	{
		g_warning("Could not update main TXT record: %s", error->message);
		g_error_free(error);
	}

	g_free(record);
}

static void mdns_service_update_disc(RODisc *disc)
{
	GError *error = NULL;

	g_return_if_fail(mdns_service);

	// "CdRom0=adVN=DiscLabel,adVT=public.cd-media"
	gchar *record = g_strdup_printf("adVN=%s,adVT=%s", disc->label, disc->type);

	const gchar *uri_basename = &disc->uri[1]; // Skip first '/'
	if (!ga_entry_group_service_set(mdns_service, uri_basename, record, &error))
	{
		g_warning("Could not update TXT record for disc at '%s': %s",
		          disc->uri, error->message);
		g_error_free(error);
	}

	g_free(record);
}

static void mdns_service_remove_disc(RODisc *disc)
{
	GError *error = NULL;
	g_return_if_fail(mdns_service);
	const gchar *uri_basename = &disc->uri[1];
	if (!ga_entry_group_service_remove_key(mdns_service, uri_basename, &error)) {
		g_warning("Could not update TXT record for disc at '%s': %s",
		          disc->uri, error->message);
		g_error_free(error);
	}
}

static void mdns_register_service()
{
	GError * error = NULL;
	if (!mdns_group) {
		mdns_group = ga_entry_group_new();

		if (!ga_entry_group_attach(mdns_group, mdns_client, &error)) {
			g_warning("Could not attach MDNS group to client: %s", error->message);
			g_error_free(error);
			return;
		}
	}

	const gchar *name = avahi_client_get_host_name(mdns_client->avahi_client);
	const unsigned int port = server_get_port();
	mdns_service = ga_entry_group_add_service(mdns_group,
	                                          name, RODISC_MDNS_SERVICE,
	                                          port, &error,
	                                          NULL);
	if (!mdns_service) {
		g_warning("Could not create service: %s", error->message);
		g_error_free(error);
		return;
	}

	// Create TXT records, disc records, etc.
	mdns_service_update();
	rodisc_refresh_all();

	if (!ga_entry_group_commit(mdns_group, &error)) {
		g_warning("Could not announce MDNS service: %s", error->message);
		g_error_free(error);
		return;
	}
}

static void mdns_client_state_changed_cb(GaClient *client, GaClientState state, gpointer user_data)
{
	switch (state) {
	case GA_CLIENT_STATE_FAILURE:
		g_warning("MDNS client state failure");
		break;
	case GA_CLIENT_STATE_S_RUNNING:
		g_debug("MDNS client found server running");
		mdns_register_service();
		break;
	case GA_CLIENT_STATE_S_COLLISION:
	case GA_CLIENT_STATE_S_REGISTERING:
		g_message("MDNS collision");
		if (mdns_group) {
			ga_entry_group_reset(mdns_group, NULL);
			mdns_service = 0;
		}
		break;
	default:
		// Do nothing
		break;
	}
}

bool mdns_start()
{
	GError *error = NULL;

	mdns_client = ga_client_new(GA_CLIENT_FLAG_NO_FLAGS);

	g_signal_connect(mdns_client, "state-changed",
	                 G_CALLBACK(mdns_client_state_changed_cb), NULL);

	if (!ga_client_start(mdns_client, &error)) {
		g_printerr("Could not start MDNS client: %s\n", error->message);
		g_error_free(error);
		return false;
	}

	return true;
}

void mdns_stop()
{
	g_object_unref(mdns_client);
}

void mdns_publish(RODisc *disc)
{
	mdns_service_freeze();
	disc_change_count++;
	mdns_service_update_disc(disc);
	mdns_service_update();
	mdns_service_thaw();
}

void mdns_unpublish(RODisc *disc)
{
	mdns_service_freeze();
	disc_change_count++;
	mdns_service_remove_disc(disc);
	mdns_service_update();
	mdns_service_thaw();
}