#include "qtavahi.h"

#include <avahi-client/client.h>
#include <avahi-client/lookup.h>
#include <avahi-client/publish.h>

#include <avahi-common/alternative.h>
#include <avahi-common/error.h>
#include <avahi-common/malloc.h>

#include <avahi-qt4/qt-watch.h>

#include <QSize>
#include <QtEndian>

#include <netinet/in.h>

namespace Avahi {

	static QHostAddress fromAvahiAddress(const AvahiAddress *address, AvahiIfIndex interface) {
		switch (address->proto) {
		case AVAHI_PROTO_INET:
			return QHostAddress(qFromBigEndian((quint32) address->data.ipv4.address));
		case AVAHI_PROTO_INET6: {
				struct sockaddr_in6 a;
				memset(&a, 0, sizeof(a));
				a.sin6_family = AF_INET6;
				a.sin6_scope_id = interface;
				memcpy(a.sin6_addr.s6_addr, address->data.ipv6.address, 16);
				return QHostAddress((const sockaddr*) &a);
			}
		case AVAHI_PROTO_UNSPEC:
			return QHostAddress();
		}
		return QHostAddress();
	}

	namespace priv {

		static void browsep_client_callback(AvahiClient *c, AvahiClientState state, void * userdata);
		static void browsep_browse_callback(AvahiServiceBrowser *b, AvahiIfIndex interface, AvahiProtocol protocol, AvahiBrowserEvent event,
											const char *name, const char *type, const char *domain, AvahiLookupResultFlags flags, void* userdata);
		static void browsep_resolve_callback(AvahiServiceResolver *r, AvahiIfIndex interface, AvahiProtocol protocol, AvahiResolverEvent event,
											 const char *name, const char *type, const char *domain, const char *host_name, const AvahiAddress *address,
											 uint16_t port, AvahiStringList *txt, AvahiLookupResultFlags flags, void* userdata);
	}
}

namespace Avahi {
	namespace priv {

		class BrowseP {
		public:
			static const ::AvahiPoll *m_qtpoll;

			QString m_serviceType;

			bool m_initialized;
			bool m_running;

			::AvahiClient *m_client;
			::AvahiServiceBrowser *m_browser;

			QByteArray m_service_type;

			Avahi::Browse *m_parent;

			QHash<ServiceKey, Service> m_list;

			BrowseP(QString servicetype, Browse *parent)
				: m_serviceType(servicetype),
				m_initialized(false), m_running(false), m_client(0), m_browser(0),
				m_service_type(servicetype.toUtf8()), m_parent(parent) {
				int err;

				if (!m_qtpoll) {
					if (!(m_qtpoll = avahi_qt_poll_get())) {
						qWarning("avahi_qt_poll_get failed");
						return;
					}
				}

				if (!(m_client = avahi_client_new(m_qtpoll, (AvahiClientFlags) 0, browsep_client_callback, this, &err))) {
					qWarning("avahi_client_new failed: %s", avahi_strerror(err));
					return;
				}

				m_initialized = true;
			}

			void clearList() {
				QList<Service> l = m_list.values();
				m_list.clear();
				for (int i = 0; i < l.size(); ++i) {
					m_parent->lostService(l.at(i));
				}
			}

			void release() {
				stop();

				if (!m_initialized) return;

				if (m_client) {
					avahi_client_free(m_client);
					m_client = 0;
				}

				m_initialized = false;
			}

			~BrowseP() {
				release();
			}

			void client_callback(AvahiClient *c, AvahiClientState state) {
				switch (state) {
				case AVAHI_CLIENT_S_RUNNING:
					break;
				case AVAHI_CLIENT_FAILURE:
					qWarning("avahi client failure: %s", avahi_strerror(avahi_client_errno(c)));
					release();
					break;
				case AVAHI_CLIENT_S_COLLISION:
				case AVAHI_CLIENT_S_REGISTERING:
					break;
				case AVAHI_CLIENT_CONNECTING:
					break;
				}
			}

			void browse_callback(AvahiServiceBrowser *b, AvahiIfIndex interface, AvahiProtocol protocol, AvahiBrowserEvent event,
								 const char *name, const char *type, const char *domain, AvahiLookupResultFlags /* flags */) {
				if (!m_browser) m_browser = b;
				Q_ASSERT(m_browser == b);

				if (protocol != AVAHI_PROTO_INET && protocol != AVAHI_PROTO_INET6) return; /* ignore non IPv[46] for now */

				/* Called whenever a new services becomes available on the LAN or is removed from the LAN */

				switch (event) {
				case AVAHI_BROWSER_FAILURE:
					qWarning("(Browser) %s", avahi_strerror(avahi_client_errno(m_client)));
					release();
					return;

				case AVAHI_BROWSER_NEW:
					qDebug("(Browser) NEW: service '%s' of type '%s' in domain '%s'", name, type, domain);

					/* We ignore the returned resolver object. In the callback
					 * function we free it. If the server is terminated before
					 * the callback function is called the server will free
					 * the resolver for us. */

					if (!(avahi_service_resolver_new(m_client, interface, protocol, name, type, domain, protocol, (AvahiLookupFlags) 0, browsep_resolve_callback, this))) {
						qWarning("Failed to resolve service '%s' on '%s': %s", name, domain, avahi_strerror(avahi_client_errno(m_client)));
					}

					break;

				case AVAHI_BROWSER_REMOVE: {
						ServiceKey k(interface, protocol, name, domain);
						Service s = m_list.value(k);
						if (s.valid()) {
							m_list.remove(k);
							m_parent->lostService(s);
						}
					}
					break;

				case AVAHI_BROWSER_ALL_FOR_NOW:
					break;
				case AVAHI_BROWSER_CACHE_EXHAUSTED:
					break;
				}
			}

			void resolve_callback(AvahiServiceResolver *r, AvahiIfIndex interface, AvahiProtocol protocol, AvahiResolverEvent event,
								  const char *name, const char *type, const char *domain, const char *host_name, const AvahiAddress *address,
								  uint16_t port, AvahiStringList *txt, AvahiLookupResultFlags /* flags */) {
				Q_ASSERT(r);

				// if (protocol != AVAHI_PROTO_INET) goto done; /* ignore non IPv4 for now */
				if (protocol != AVAHI_PROTO_INET && protocol != AVAHI_PROTO_INET6) goto done; /* ignore non IPv[46] for now */

				/* Called whenever a service has been resolved successfully or timed out */

				switch (event) {
				case AVAHI_RESOLVER_FAILURE:
					qDebug("(Resolver) Failed to resolve service '%s' of type '%s' at '%s' in domain '%s': %s", name, type, host_name, domain, avahi_strerror(avahi_client_errno(m_client)));
					break;

				case AVAHI_RESOLVER_FOUND: {
						qDebug("(Resolver) found service '%s' of type '%s' at '%s' in domain '%s'", name, type, host_name, domain);
						QHash<QString, QString> qtxt;
						AvahiStringList *psl;
						for (psl = txt ; psl ; psl = psl->next) {
							QString e = QString::fromUtf8((const char*) psl->text, psl->size), key, value;
							int eqPos = e.indexOf(QChar('='));
							if (eqPos == 0) continue; /* ignore empty keys */
							if (eqPos < 0) { /* "boolean" */
								key = e;
							} else {
								key = e.left(eqPos);
								value = e.mid(eqPos + 1);
							}
							key = key.toLower();
							// qDebug() << "Resolver: key = " << key << ", value = " << value;
							qtxt.insert(key, value);
						}

						ServiceKey k(interface, protocol, name, domain);
						Service s = m_list.value(k);
						if (s.valid()) {
							m_list.remove(k);
							m_parent->lostService(s);
						}

						s = Service(QString::fromUtf8(name), QString::fromUtf8(host_name), QString::fromUtf8(domain), fromAvahiAddress(address, interface), interface, protocol, port, qtxt);
						m_list.insert(k, s);
						m_parent->foundService(s);
					}
				}

				done:
				avahi_service_resolver_free(r);
			}

			bool start() {
				if (m_running) return true;
				if (!m_initialized) return false;

				clearList();

				if (NULL == (m_browser = avahi_service_browser_new(m_client, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, m_service_type.constData(), NULL, (AvahiLookupFlags) 0, browsep_browse_callback, this))) {
					qWarning("Failed to create service browser: %s", avahi_strerror(avahi_client_errno(m_client)));
					return false;
				}

				emit m_parent->started();
				m_running = true;

				return true;
			}

			void stop() {
				clearList();
				if (m_running) {
					emit m_parent->stopped();
					m_running = false;
				}
				if (m_browser) {
					avahi_service_browser_free(m_browser);
					m_browser = 0;
				}
			}
		};
		const AvahiPoll *BrowseP::m_qtpoll = 0;

		static void browsep_client_callback(AvahiClient *c, AvahiClientState state, void * userdata) {
			BrowseP *p = static_cast<BrowseP*>(userdata);
			p->client_callback(c, state);
		}

		static void browsep_browse_callback(AvahiServiceBrowser *b, AvahiIfIndex interface, AvahiProtocol protocol, AvahiBrowserEvent event,
											const char *name, const char *type, const char *domain, AvahiLookupResultFlags flags, void* userdata) {
			BrowseP *p = static_cast<BrowseP*>(userdata);
			p->browse_callback(b, interface, protocol, event, name, type, domain, flags);
		}

		static void browsep_resolve_callback(AvahiServiceResolver *r, AvahiIfIndex interface, AvahiProtocol protocol, AvahiResolverEvent event,
											 const char *name, const char *type, const char *domain, const char *host_name, const AvahiAddress *address,
											 uint16_t port, AvahiStringList *txt, AvahiLookupResultFlags flags, void* userdata) {
			BrowseP *p = static_cast<BrowseP*>(userdata);
			p->resolve_callback(r, interface, protocol, event, name, type, domain, host_name, address, port, txt, flags);
		}

		static void announcep_client_callback(AvahiClient *c, AvahiClientState state, void * userdata);
		static void announcep_entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, void *userdata);

		class AnnounceP {
		public:
			static const AvahiPoll *m_qtpoll;

			QString m_serviceType, m_name;
			quint16 m_port;
			QHash<QString,QString> m_txt;

			bool m_initialized;
			bool m_running;

			AvahiClient *m_client;
			AvahiEntryGroup *m_group;

			QByteArray m_service_type;

			Announce *m_parent;

			char *m_raw_name; /* avahi string */
			QList<QByteArray> m_txt_list;
			::AvahiStringList *m_raw_txt;

			AnnounceP(QString serviceType, QString name, quint16 port, QHash<QString,QString> txt, Announce *parent)
				: m_serviceType(serviceType), m_name(name), m_port(port), m_txt(txt),
				m_initialized(false), m_running(false), m_client(0), m_group(0),
				m_service_type(serviceType.toUtf8()), m_parent(parent),
				m_raw_name(avahi_strdup(name.toUtf8().constData())), m_raw_txt(0) {
				int err;

				QHashIterator<QString, QString> i(m_txt);
				while (i.hasNext()) {
					QByteArray a;
					i.next();
					if (i.value().isNull()) {
						m_txt_list.append(a = i.key().toUtf8());
					} else {
						m_txt_list.append(a = QString("%1=%2").arg(i.key(), i.value()).toUtf8());
					}
					AvahiStringList *l = avahi_string_list_new(a.constData(), NULL);
					l->next = m_raw_txt;
					m_raw_txt = l;
				}

				if (!m_qtpoll) {
					if (!(m_qtpoll = avahi_qt_poll_get())) {
						qWarning("avahi_qt_poll_get failed");
						return;
					}
				}

				if (!(m_client = avahi_client_new(m_qtpoll, (AvahiClientFlags) 0, announcep_client_callback, this, &err))) {
					qWarning("avahi_client_new failed: %s", avahi_strerror(err));
					return;
				}

				m_initialized = true;

				start();
			}

			void release() {
				if (m_running) {
					m_running = false;
				}
				if (!m_initialized) return;

				if (m_group) {
					qDebug("avahi unregister service");
					avahi_entry_group_reset(m_group);
					avahi_entry_group_free(m_group);
					m_group = 0;
				}

				if (m_client) {
					avahi_client_free(m_client);
					m_client = 0;
				}

				m_initialized = false;

				emit m_parent->stopped();
			}

			~AnnounceP() {
				release();
				if (m_raw_name) {
					avahi_free(m_raw_name);
					m_raw_name = 0;
				}
				if (m_raw_txt) {
					avahi_string_list_free(m_raw_txt);
					m_raw_txt = 0;
				}
			}

			void client_callback(AvahiClient *c, AvahiClientState state) {
				m_client = c;
				switch (state) {
				case AVAHI_CLIENT_S_RUNNING:
					create_services();
					break;
				case AVAHI_CLIENT_FAILURE:
					qDebug("avahi client failure");
					release();
					break;
				case AVAHI_CLIENT_S_COLLISION:
				case AVAHI_CLIENT_S_REGISTERING:
					if (m_group) {
						avahi_entry_group_reset(m_group);
					}
					break;
		case AVAHI_CLIENT_CONNECTING:
					break;
				}
			}

			void entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state) {
				m_group = g;

				switch (state) {
				case AVAHI_ENTRY_GROUP_ESTABLISHED :
					emit m_parent->established();
					break;

				case AVAHI_ENTRY_GROUP_COLLISION :
					{
						char *n = avahi_alternative_service_name(m_raw_name);
						avahi_free(m_raw_name);
						m_raw_name = n;
						m_name = QString::fromUtf8(m_raw_name);
					}

					/* And recreate the services */
					avahi_entry_group_reset(m_group);
					create_services();
					/* same name should result in AVAHI_ERR_COLLISION in create_services, emit collision there. */
					break;

				case AVAHI_ENTRY_GROUP_FAILURE :
					qDebug("Entry group failure: %s", avahi_strerror(avahi_client_errno(m_client)));

					release();
					break;

				case AVAHI_ENTRY_GROUP_UNCOMMITED:
				case AVAHI_ENTRY_GROUP_REGISTERING:
					break;
				}
			}

			bool create_services() {
				int ret;

				if (!m_group) {
					if (!(m_group = avahi_entry_group_new(m_client, announcep_entry_group_callback, this))) {
						qDebug("avahi_entry_group_new failed: %s", avahi_strerror(avahi_client_errno(m_client)));
						release();
						return false;
					}
				}

				again:
				if (avahi_entry_group_is_empty(m_group)) {
					if ((ret = avahi_entry_group_add_service_strlst(m_group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, (AvahiPublishFlags) 0, m_raw_name, m_service_type.constData(), NULL, NULL, m_port, m_raw_txt)) < 0) {

						if (ret == AVAHI_ERR_COLLISION)
							goto collision;

						qDebug("Failed to add '%s': %s", m_service_type.constData(), avahi_strerror(ret));
						release();
						return false;
					}
					if ((ret = avahi_entry_group_commit(m_group)) < 0) {
						qDebug("Failed to commit entry group: %s", avahi_strerror(ret));
						release();
						return false;
					}
				}

				return true;

				collision:
				qDebug("avahi name collision: %s, trying a new one", m_raw_name);
				{
					char *n = avahi_alternative_service_name(m_raw_name);
					avahi_free(m_raw_name);
					m_raw_name = n;
					m_name = QString::fromUtf8(m_raw_name);
				}
				avahi_entry_group_reset(m_group);
				emit m_parent->collision();
				goto again;
			}

			bool start() {
				if (m_running) return true;
				if (!m_initialized) return false;

				m_running = true;
				emit m_parent->started();

				return true;
			}

			void stop() {
				release();
			}
		};
		const AvahiPoll *AnnounceP::m_qtpoll = 0;

		static void announcep_client_callback(AvahiClient *c, AvahiClientState state, void * userdata) {
			AnnounceP *p = static_cast<AnnounceP*>(userdata);
			p->client_callback(c, state);
		}
		static void announcep_entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, void *userdata) {
			AnnounceP *p = static_cast<AnnounceP*>(userdata);
			p->entry_group_callback(g, state);
		}
	}

	/* public interfaces */

	Browse::Browse(QString serviceType, QObject *parent)
		: QObject(parent), m_priv(new priv::BrowseP(serviceType, this)) {
	}

	Browse::~Browse() {
		delete m_priv;
		m_priv = 0;
	}

	bool Browse::start() {
		return m_priv->start();
	}

	void Browse::stop() {
		m_priv->stop();
	}

	QString Browse::serviceType() const {
		return m_priv->m_serviceType;
	}

	QList<Service> Browse::currentList() const {
		return m_priv->m_list.values();
	}

	void Browse::foundService(Avahi::Service s) {
		emit found(s);
	}

	void Browse::lostService(Avahi::Service s) {
		emit lost(s);
		if (s.m_priv && s.m_priv->m_watcher) {
			emit s.m_priv->m_watcher->lost(s);
		}
	}


	Announce::Announce(QString serviceType, QString name, quint16 port, QHash<QString,QString> txt, QObject *parent)
		: QObject(parent), m_priv(new priv::AnnounceP(serviceType, name, port, txt, this)) {
	}

	Announce::~Announce() {
		delete m_priv;
		m_priv = 0;
	}

	bool Announce::start() {
		return m_priv->start();
	}

	void Announce::stop() {
		m_priv->stop();
	}

	QString Announce::serviceType() const {
		return m_priv->m_serviceType;
	}

	QString Announce::name() const {
		return m_priv->m_name;
	}
	quint16 Announce::port() const {
		return m_priv->m_port;
	}
	QHash<QString, QString> Announce::txt() const {
		return m_priv->m_txt;
	}
	QString Announce::txt(QString key) const {
		return m_priv->m_txt.value(key);
	}

}