/*******************************************************************************
 * RetroShare Broadcast Domain Discovery                                       *
 *                                                                             *
 * Copyright (C) 2019  Gioacchino Mazzurco <gio@altermundi.net>                *
 *                                                                             *
 * This program is free software: you can redistribute it and/or modify        *
 * it under the terms of the GNU Lesser General Public License as              *
 * published by the Free Software Foundation, either version 3 of the          *
 * License, or (at your option) any later version.                             *
 *                                                                             *
 * This program 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 Lesser General Public License for more details.                         *
 *                                                                             *
 * You should have received a copy of the GNU Lesser General Public License    *
 * along with this program. If not, see <https://www.gnu.org/licenses/>.       *
 *                                                                             *
 *******************************************************************************/
#pragma once

#include <functional>
#include <memory>
#include <vector>
#include <string>

#include "retroshare/rsids.h"
#include "retroshare/rstypes.h"
#include "serialiser/rsserializable.h"
#include "util/rstime.h"
#include "util/rsurl.h"
#include "util/rsmemory.h"
#include "retroshare/rsevents.h"

class RsBroadcastDiscovery;

/**
 * Pointer to global instance of RsBroadcastDiscovery service implementation
 * @jsonapi{development}
 *
 * TODO: this should become std::weak_ptr once we have a reasonable services
 * management.
 */
extern RsBroadcastDiscovery* rsBroadcastDiscovery;


struct RsBroadcastDiscoveryResult : RsSerializable
{
	RsPgpFingerprint mPgpFingerprint;
	RsPeerId mSslId;
	std::string mProfileName;
	RsUrl mLocator;

	/// @see RsSerializable
	void serial_process( RsGenericSerializer::SerializeJob j,
	                     RsGenericSerializer::SerializeContext& ctx) override
	{
		RS_SERIAL_PROCESS(mPgpFingerprint);
		RS_SERIAL_PROCESS(mSslId);
		RS_SERIAL_PROCESS(mProfileName);
		RS_SERIAL_PROCESS(mLocator);
	}

	RsBroadcastDiscoveryResult() = default;
	RsBroadcastDiscoveryResult (const RsBroadcastDiscoveryResult&) = default;
	~RsBroadcastDiscoveryResult() override;
};


/**
 * @brief Event emitted when a non friend new peer is found in the local network
 * @see RsEvents
 */
enum class RsBroadcastDiscoveryEventType: uint32_t {
    UNKNOWN               = 0x00,
    PEER_FOUND            = 0x01
};

struct RsBroadcastDiscoveryEvent : RsEvent
{
	RsBroadcastDiscoveryEvent()
      : RsEvent(RsEventType::BROADCAST_DISCOVERY),
        mDiscoveryEventType(RsBroadcastDiscoveryEventType::UNKNOWN)
    {}

    virtual ~RsBroadcastDiscoveryEvent() override = default;

    RsBroadcastDiscoveryEventType  mDiscoveryEventType;
	RsBroadcastDiscoveryResult     mData;

	/// @see RsSerializable
	void serial_process( RsGenericSerializer::SerializeJob j,
	                     RsGenericSerializer::SerializeContext& ctx) override
	{
		RsEvent::serial_process(j, ctx);

		RS_SERIAL_PROCESS(mDiscoveryEventType);
		RS_SERIAL_PROCESS(mData);
	}
};


/**
 * Announce own RetroShare instace and look friends and peers in own broadcast
 * domain (aka LAN).
 * Emit event @see RsBroadcastDiscoveryPeerFoundEvent when a new peer (not
 * friend yet) is found.
 */
class RsBroadcastDiscovery
{
public:
	/**
	 * @brief Get potential peers that have been discovered up until now
	 * @jsonapi{development}
	 * @return vector containing discovered peers, may be empty.
	 */
	virtual std::vector<RsBroadcastDiscoveryResult> getDiscoveredPeers() = 0;

	/**
	 * @brief Check if multicast listening is enabled
	 * @jsonapi{development}
	 * On some platforms such as Android multicast listening, which is needed
	 * for broadcast discovery, is not enabled by default at WiFi driver level
	 * @see enableMulticastListening, so this method check if it is enabled.
	 * On platforms that are not expected to have such a limitation this method
	 * always return true.
	 * @return true if enabled, false otherwise.
	 */
	virtual bool isMulticastListeningEnabled() = 0;

	/**
	 * @brief On platforms that need it enable low level multicast listening
	 * @jsonapi{development}
	 * On Android and potencially other mobile platforms, WiFi drivers are
	 * configured by default to discard any packet that is not directed to the
	 * unicast mac address of the interface, this way they could save some
	 * battery but breaks anything that is not unicast, such as broadcast
	 * discovery. On such platforms this method enable low level multicast
	 * listening so we can receive advertisement from same broadcast domain
	 * nodes.
	 * On platforms without such limitation does nothing and always return
	 * false.
	 * It is exposed as a public API so the UI can decide the right equilibrium
	 * between discoverability and battery saving.
	 * @return true if multicast listening has been enabled due to this call,
	 *	false otherwise.
	 */
	virtual bool enableMulticastListening() = 0;

	/**
	 * @brief Disable multicast listening
	 * @jsonapi{development}
	 * The opposite of @see enableMulticastListening.
	 * @return true if multicast listening has been disabled due to this call,
	 *	false otherwise.
	 */
	virtual bool disableMulticastListening() = 0;

	virtual ~RsBroadcastDiscovery();
};