/*
* Copyright (c) 2013-2024, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/

#ifndef TUNNEL_BASE_H__
#define TUNNEL_BASE_H__

#include <inttypes.h>
#include <memory>
#include <future>
#include <list>
#include "Timestamp.h"
#include "I2NPProtocol.h"
#include "Identity.h"

namespace i2p
{
namespace transport
{
	class TransportSession;
}	
	
namespace tunnel
{
	const size_t TUNNEL_DATA_MSG_SIZE = 1028;
	const size_t TUNNEL_DATA_ENCRYPTED_SIZE = 1008;
	const size_t TUNNEL_DATA_MAX_PAYLOAD_SIZE = 1003;

	enum TunnelDeliveryType
	{
		eDeliveryTypeLocal = 0,
		eDeliveryTypeTunnel = 1,
		eDeliveryTypeRouter = 2
	};
	struct TunnelMessageBlock
	{
		TunnelDeliveryType deliveryType;
		i2p::data::IdentHash hash;
		uint32_t tunnelID;
		std::shared_ptr<I2NPMessage> data;
	};

	class TunnelBase
	{
		public:

			TunnelBase (uint32_t tunnelID, uint32_t nextTunnelID, const i2p::data::IdentHash& nextIdent):
				m_TunnelID (tunnelID), m_NextTunnelID (nextTunnelID), m_NextIdent (nextIdent),
				m_CreationTime (i2p::util::GetSecondsSinceEpoch ()) {};
			virtual ~TunnelBase () {};
			virtual void Cleanup () {};

			virtual void HandleTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage>&& tunnelMsg) = 0;
			virtual void SendTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage> msg) = 0;
			virtual void FlushTunnelDataMsgs () {};
			virtual void EncryptTunnelMsg (std::shared_ptr<const I2NPMessage> in, std::shared_ptr<I2NPMessage> out) = 0;
			uint32_t GetNextTunnelID () const { return m_NextTunnelID; };
			const i2p::data::IdentHash& GetNextIdentHash () const { return m_NextIdent; };
			virtual uint32_t GetTunnelID () const { return m_TunnelID; }; // as known at our side

			uint32_t GetCreationTime () const { return m_CreationTime; };
			void SetCreationTime (uint32_t t) { m_CreationTime = t; };

		private:

			uint32_t m_TunnelID, m_NextTunnelID;
			i2p::data::IdentHash m_NextIdent;
			uint32_t m_CreationTime; // seconds since epoch
	};

	struct TunnelCreationTimeCmp
	{
		template<typename T>
		bool operator() (const std::shared_ptr<T> & t1, const std::shared_ptr<T> & t2) const
		{
			if (t1->GetCreationTime () != t2->GetCreationTime ())
				return t1->GetCreationTime () > t2->GetCreationTime ();
			else
				return t1 < t2;
		}
	};

	class TunnelTransportSender final
	{
		public: 

			TunnelTransportSender () = default;
			~TunnelTransportSender () = default;

			void SendMessagesTo (const i2p::data::IdentHash& to, std::list<std::shared_ptr<I2NPMessage> >&& msgs);
			void SendMessagesTo (const i2p::data::IdentHash& to, std::list<std::shared_ptr<I2NPMessage> >& msgs); // send and clear

			std::shared_ptr<const i2p::transport::TransportSession> GetCurrentTransport () const { return m_CurrentTransport.lock (); }
			void Reset ();
			
		private:
			
			std::weak_ptr<i2p::transport::TransportSession> m_CurrentTransport;
			std::future<std::shared_ptr<i2p::transport::TransportSession> > m_PendingTransport;
	};	
}
}

#endif