#include <algorithm>
#include <mutex>
#include <boost/lexical_cast.hpp>
#include <cryptopp/dh.h>
#include "Log.h"
#include "util.h"
#include "Timestamp.h"
#include "NetDb.h"
#include "Destination.h"
#include "ClientContext.h"

namespace i2p
{
namespace client
{
	ClientDestination::ClientDestination (const i2p::data::PrivateKeys& keys, bool isPublic, 
			const std::map<std::string, std::string> * params):
		m_IsRunning (false), m_Thread (nullptr), m_Work (m_Service),	
		m_Keys (keys), m_LeaseSet (nullptr), m_IsPublic (isPublic), m_PublishReplyToken (0),
		m_DatagramDestination (nullptr), m_PublishConfirmationTimer (m_Service)
	{
		CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
		dh.GenerateKeyPair(i2p::context.GetRandomNumberGenerator (), m_EncryptionPrivateKey, m_EncryptionPublicKey);
		int inboundTunnelLen = DEFAULT_INBOUND_TUNNEL_LENGTH;
		int outboundTunnelLen = DEFAULT_OUTBOUND_TUNNEL_LENGTH;
		if (params)
		{
			auto it = params->find (I2CP_PARAM_INBOUND_TUNNEL_LENGTH);
			if (it != params->end ())
			{	
				int len = boost::lexical_cast<int>(it->second);
				if (len > 0)
				{
					inboundTunnelLen = len;
					LogPrint (eLogInfo, "Inbound tunnel length set to ", len);
				}
			}	
			it = params->find (I2CP_PARAM_OUTBOUND_TUNNEL_LENGTH);
			if (it != params->end ())
			{
				int len = boost::lexical_cast<int>(it->second);
				if (len > 0)
				{
					outboundTunnelLen = len;
					LogPrint (eLogInfo, "Outbound tunnel length set to ", len);
				}
			}	
		}	
		m_Pool = i2p::tunnel::tunnels.CreateTunnelPool (this, inboundTunnelLen, outboundTunnelLen);  
		if (m_IsPublic)
			LogPrint (eLogInfo, "Local address ", GetIdentHash ().ToBase32 (), ".b32.i2p created");
		m_StreamingDestination = new i2p::stream::StreamingDestination (*this); // TODO:
	}

	ClientDestination::~ClientDestination ()
	{
		if (m_IsRunning)	
			Stop ();
		for (auto it: m_LeaseSetRequests)
			delete it.second;
		for (auto it: m_RemoteLeaseSets)
			delete it.second;
		if (m_Pool)
			i2p::tunnel::tunnels.DeleteTunnelPool (m_Pool);		
		if (m_StreamingDestination)
			delete m_StreamingDestination;
		if (m_DatagramDestination)
			delete m_DatagramDestination;
	}	

	void ClientDestination::Run ()
	{
		while (m_IsRunning)
		{
			try
			{	
				m_Service.run ();
			}
			catch (std::exception& ex)
			{
				LogPrint ("Destination: ", ex.what ());
			}	
		}	
	}	

	void ClientDestination::Start ()
	{	
		m_Pool->SetLocalDestination (this);
		m_Pool->SetActive (true);
		m_IsRunning = true;
		m_Thread = new std::thread (std::bind (&ClientDestination::Run, this));
		m_StreamingDestination->Start ();	
	}
		
	void ClientDestination::Stop ()
	{	
		m_StreamingDestination->Stop ();	
		if (m_DatagramDestination)
		{
			auto d = m_DatagramDestination;
			m_DatagramDestination = nullptr;
			delete d;
		}	
		if (m_Pool)
		{	
			m_Pool->SetLocalDestination (nullptr);
			i2p::tunnel::tunnels.StopTunnelPool (m_Pool);
		}	
		m_IsRunning = false;
		m_Service.stop ();
		if (m_Thread)
		{	
			m_Thread->join (); 
			delete m_Thread;
			m_Thread = 0;
		}	
	}	

	const i2p::data::LeaseSet * ClientDestination::FindLeaseSet (const i2p::data::IdentHash& ident)
	{
		auto it = m_RemoteLeaseSets.find (ident);
		if (it != m_RemoteLeaseSets.end ())
		{	
			if (it->second->HasNonExpiredLeases ())
				return it->second;
			else
			{
				LogPrint ("All leases of remote LeaseSet expired. Request it");
				RequestDestination (ident);
			}	
		}	
		else
		{	
			auto ls = i2p::data::netdb.FindLeaseSet (ident);
			if (ls)
			{
				ls = new i2p::data::LeaseSet (*ls);
				m_RemoteLeaseSets[ident] = ls;			
				return ls;
			}	
		}
		return nullptr;
	}	

	const i2p::data::LeaseSet * ClientDestination::GetLeaseSet ()
	{
		if (!m_Pool) return nullptr;
		if (!m_LeaseSet)
			UpdateLeaseSet ();
		return m_LeaseSet;
	}	

	void ClientDestination::UpdateLeaseSet ()
	{
		auto newLeaseSet = new i2p::data::LeaseSet (*m_Pool);
		if (!m_LeaseSet)
			m_LeaseSet = newLeaseSet;
		else
		{	
			// TODO: implement it better
			*m_LeaseSet = *newLeaseSet;
			delete newLeaseSet;
		}	
	}	

	bool ClientDestination::SubmitSessionKey (const uint8_t * key, const uint8_t * tag)
	{
		struct
		{
			uint8_t k[32], t[32];
		} data;	
		memcpy (data.k, key, 32);
		memcpy (data.t, tag, 32);
		m_Service.post ([this,data](void)
			{
				this->AddSessionKey (data.k, data.t);
			});
		return true;
	}

	void ClientDestination::ProcessGarlicMessage (I2NPMessage * msg)
	{
		m_Service.post (std::bind (&ClientDestination::HandleGarlicMessage, this, msg)); 
	}

	void ClientDestination::ProcessDeliveryStatusMessage (I2NPMessage * msg)
	{
		m_Service.post (std::bind (&ClientDestination::HandleDeliveryStatusMessage, this, msg)); 
	}

	void ClientDestination::HandleI2NPMessage (const uint8_t * buf, size_t len, i2p::tunnel::InboundTunnel * from)
	{
		uint8_t typeID = buf[I2NP_HEADER_TYPEID_OFFSET];
		switch (typeID)
		{	
			case eI2NPData:
				HandleDataMessage (buf + I2NP_HEADER_SIZE, bufbe16toh (buf + I2NP_HEADER_SIZE_OFFSET));
			break;
			case eI2NPDatabaseStore:
				HandleDatabaseStoreMessage (buf + I2NP_HEADER_SIZE, bufbe16toh (buf + I2NP_HEADER_SIZE_OFFSET));
			break;
			case eI2NPDatabaseSearchReply:
				HandleDatabaseSearchReplyMessage (buf + I2NP_HEADER_SIZE, bufbe16toh (buf + I2NP_HEADER_SIZE_OFFSET));
			break;	
			default:
				i2p::HandleI2NPMessage (CreateI2NPMessage (buf, GetI2NPMessageLength (buf), from));
		}		
	}	

	void ClientDestination::HandleDatabaseStoreMessage (const uint8_t * buf, size_t len)
	{
		I2NPDatabaseStoreMsg msg;
		memcpy(&msg,buf,sizeof (I2NPDatabaseStoreMsg));
		size_t offset = sizeof (I2NPDatabaseStoreMsg);
		if (msg.replyToken) // TODO:
			offset += 36;
		if (msg.type == 1) // LeaseSet
		{
			LogPrint (eLogDebug, "Remote LeaseSet");
			auto it = m_RemoteLeaseSets.find (msg.key);
			if (it != m_RemoteLeaseSets.end ())
			{
				it->second->Update (buf + offset, len - offset); 
				LogPrint (eLogDebug, "Remote LeaseSet updated");
			}
			else
			{	
				LogPrint (eLogDebug, "New remote LeaseSet added");
				m_RemoteLeaseSets[msg.key] = new i2p::data::LeaseSet (buf + offset, len - offset);
			}	
		}	
		else
			LogPrint (eLogError, "Unexpected client's DatabaseStore type ", msg.type, ". Dropped");
		
		auto it1 = m_LeaseSetRequests.find (msg.key);
		if (it1 != m_LeaseSetRequests.end ())
		{
			it1->second->requestTimeoutTimer.cancel ();
			if (it1->second->requestComplete) it1->second->requestComplete (true);
			delete it1->second;
			m_LeaseSetRequests.erase (it1);
		}	
	}	

	void ClientDestination::HandleDatabaseSearchReplyMessage (const uint8_t * buf, size_t len)
	{
		i2p::data::IdentHash key (buf);
		int num = buf[32]; // num
		LogPrint ("DatabaseSearchReply for ", key.ToBase64 (), " num=", num);
		auto it = m_LeaseSetRequests.find (key);
		if (it != m_LeaseSetRequests.end ())
		{
			LeaseSetRequest * request = it->second;
			bool found = false;
			if (request->excluded.size () < MAX_NUM_FLOODFILLS_PER_REQUEST)
			{	
				for (int i = 0; i < num; i++)
				{
					i2p::data::IdentHash peerHash (buf + 33 + i*32);
					auto floodfill = i2p::data::netdb.FindRouter (peerHash);
					if (floodfill)
					{
						LogPrint (eLogInfo, "Requesting ", key.ToBase64 (), " at ", peerHash.ToBase64 ());
						if (SendLeaseSetRequest (key, floodfill, request))
							found = true;
					}	
					else
					{	
						LogPrint (eLogInfo, "Found new floodfill. Request it");
						i2p::data::netdb.RequestDestination (peerHash);
					}	
				}
				if (!found)
					LogPrint (eLogError, "Suggested floodfills are not presented in netDb"); 
			}	
			else
				LogPrint (eLogInfo, key.ToBase64 (), " was not found on ",  MAX_NUM_FLOODFILLS_PER_REQUEST," floodfills");
			if (!found)
			{
				if (request->requestComplete) request->requestComplete (false);
				delete request;
				m_LeaseSetRequests.erase (key);
			}	
		}	
		else	
			LogPrint ("Request for ", key.ToBase64 (), " not found");
	}	
		
	void ClientDestination::HandleDeliveryStatusMessage (I2NPMessage * msg)
	{
		I2NPDeliveryStatusMsg * deliveryStatus = (I2NPDeliveryStatusMsg *)msg->GetPayload ();
		uint32_t msgID = bufbe32toh (&(deliveryStatus->msgID));
		if (msgID == m_PublishReplyToken)
		{
			LogPrint (eLogDebug, "Publishing confirmed");
			m_ExcludedFloodfills.clear ();
			m_PublishReplyToken = 0;
			i2p::DeleteI2NPMessage (msg);
		}
		else
			i2p::garlic::GarlicDestination::HandleDeliveryStatusMessage (msg);
	}	

	void ClientDestination::SetLeaseSetUpdated ()
	{
		i2p::garlic::GarlicDestination::SetLeaseSetUpdated ();	
		UpdateLeaseSet ();
		if (m_IsPublic)
			Publish ();
	}
		
	void ClientDestination::Publish ()
	{	
		if (!m_LeaseSet || !m_Pool) 
		{
			LogPrint (eLogError, "Can't publish non-existing LeaseSet");
			return;
		}
		if (m_PublishReplyToken)
		{
			LogPrint (eLogInfo, "Publishing is pending");
			return;
		}
		auto outbound = m_Pool->GetNextOutboundTunnel ();
		if (!outbound)
		{
			LogPrint ("Can't publish LeaseSet. No outbound tunnels");
			return;
		}
		std::set<i2p::data::IdentHash> excluded; 
		auto floodfill = i2p::data::netdb.GetClosestFloodfill (m_LeaseSet->GetIdentHash (), m_ExcludedFloodfills);	
		if (!floodfill)
		{
			LogPrint ("Can't publish LeaseSet. No more floodfills found");
			m_ExcludedFloodfills.clear ();
			return;
		}	
		m_ExcludedFloodfills.insert (floodfill->GetIdentHash ());
		LogPrint (eLogDebug, "Publish LeaseSet of ", GetIdentHash ().ToBase32 ());
		m_PublishReplyToken = i2p::context.GetRandomNumberGenerator ().GenerateWord32 ();
		auto msg = WrapMessage (*floodfill, i2p::CreateDatabaseStoreMsg (m_LeaseSet, m_PublishReplyToken));			
		m_PublishConfirmationTimer.expires_from_now (boost::posix_time::seconds(PUBLISH_CONFIRMATION_TIMEOUT));
		m_PublishConfirmationTimer.async_wait (std::bind (&ClientDestination::HandlePublishConfirmationTimer,
			this, std::placeholders::_1));	
		outbound->SendTunnelDataMsg (floodfill->GetIdentHash (), 0, msg);	
	}

	void ClientDestination::HandlePublishConfirmationTimer (const boost::system::error_code& ecode)
	{
		if (ecode != boost::asio::error::operation_aborted)
		{	
			if (m_PublishReplyToken)
			{
				LogPrint (eLogWarning, "Publish confirmation was not received in ", PUBLISH_CONFIRMATION_TIMEOUT,  "seconds. Try again");
				m_PublishReplyToken = 0;
				Publish ();
			}
		}
	}

	void ClientDestination::HandleDataMessage (const uint8_t * buf, size_t len)
	{
		uint32_t length = bufbe32toh (buf);
		buf += 4;
		// we assume I2CP payload
		switch (buf[9])
		{
			case PROTOCOL_TYPE_STREAMING:
				// streaming protocol
				if (m_StreamingDestination)
					m_StreamingDestination->HandleDataMessagePayload (buf, length);
				else
					LogPrint ("Missing streaming destination");
			break;
			case PROTOCOL_TYPE_DATAGRAM:
				// datagram protocol
				if (m_DatagramDestination)
					m_DatagramDestination->HandleDataMessagePayload (buf, length);
				else
					LogPrint ("Missing streaming destination");
			break;
			default:
				LogPrint ("Data: unexpected protocol ", buf[9]);
		}
	}	

	std::shared_ptr<i2p::stream::Stream> ClientDestination::CreateStream (const std::string& dest, int port) {
		i2p::data::IdentHash identHash;
		if (i2p::client::context.GetAddressBook ().GetIdentHash (dest, identHash))
			return CreateStream (identHash, port);
		else
		{
			LogPrint (eLogWarning, "Remote destination ", dest, " not found");
			return nullptr;
		}
	}

	std::shared_ptr<i2p::stream::Stream> ClientDestination::CreateStream (const i2p::data::IdentHash& dest, int port) {
		const i2p::data::LeaseSet * leaseSet = FindLeaseSet (dest);
		if (!leaseSet)
		{
			bool found = false;
			std::condition_variable newDataReceived;
			std::mutex newDataReceivedMutex;
			std::unique_lock<std::mutex> l(newDataReceivedMutex);
			RequestDestination (dest,
				[&newDataReceived, &found](bool success)
				{
					found = success;
					newDataReceived.notify_all ();
				});
			if (newDataReceived.wait_for (l, std::chrono::seconds (STREAM_REQUEST_TIMEOUT)) == std::cv_status::timeout)
				LogPrint (eLogError, "Subscription LeseseSet request timeout expired");
			if (found)
				leaseSet = FindLeaseSet (dest);
		}
		if (leaseSet)
			return CreateStream (*leaseSet, port);
		else
			return nullptr;
	}

	std::shared_ptr<i2p::stream::Stream> ClientDestination::CreateStream (const i2p::data::LeaseSet& remote, int port)
	{
		if (m_StreamingDestination)
			return m_StreamingDestination->CreateNewOutgoingStream (remote, port);
		return nullptr;	
	}

	void ClientDestination::AcceptStreams (const i2p::stream::StreamingDestination::Acceptor& acceptor)
	{
		if (m_StreamingDestination)
			m_StreamingDestination->SetAcceptor (acceptor);
	}

	void ClientDestination::StopAcceptingStreams ()
	{
		if (m_StreamingDestination)
			m_StreamingDestination->ResetAcceptor ();
	}

	bool ClientDestination::IsAcceptingStreams () const
	{
		if (m_StreamingDestination)
			return m_StreamingDestination->IsAcceptorSet ();
		return false;
	}	

	i2p::datagram::DatagramDestination * ClientDestination::CreateDatagramDestination ()
	{
		if (!m_DatagramDestination)
			m_DatagramDestination = new i2p::datagram::DatagramDestination (*this);
		return m_DatagramDestination;	
	}

	bool ClientDestination::RequestDestination (const i2p::data::IdentHash& dest, RequestComplete requestComplete)
	{
		if (!m_Pool || !IsReady ()) return false;
		m_Service.post (std::bind (&ClientDestination::RequestLeaseSet, this, dest, requestComplete));
		return true;
	}

	void ClientDestination::RequestLeaseSet (const i2p::data::IdentHash& dest, RequestComplete requestComplete)
	{
		std::set<i2p::data::IdentHash> excluded;
		auto floodfill = i2p::data::netdb.GetClosestFloodfill (dest, excluded);
		if (floodfill)
		{
			LeaseSetRequest * request = new LeaseSetRequest (m_Service);
			request->requestComplete = requestComplete;
			m_LeaseSetRequests[dest] = request;
			if (!SendLeaseSetRequest (dest, floodfill, request))
			{
				// request failed
				if (request->requestComplete) request->requestComplete (false);
				delete request;
				m_LeaseSetRequests.erase (dest);
			}		
		}	
		else
			LogPrint (eLogError, "No floodfills found");	
	}	
		
	bool ClientDestination::SendLeaseSetRequest (const i2p::data::IdentHash& dest, 
		std::shared_ptr<const i2p::data::RouterInfo>  nextFloodfill, LeaseSetRequest * request)
	{
		auto replyTunnel = m_Pool->GetNextInboundTunnel ();
		if (!replyTunnel) LogPrint (eLogError, "No inbound tunnels found");	
		
		auto outboundTunnel = m_Pool->GetNextOutboundTunnel ();
		if (!outboundTunnel) LogPrint (eLogError, "No outbound tunnels found");		
			
		if (replyTunnel && outboundTunnel)
		{	
			request->excluded.insert (nextFloodfill->GetIdentHash ());
			request->requestTime = i2p::util::GetSecondsSinceEpoch ();
			request->requestTimeoutTimer.cancel ();

			CryptoPP::AutoSeededRandomPool rnd;
			uint8_t replyKey[32], replyTag[32];
			rnd.GenerateBlock (replyKey, 32); // random session key 
			rnd.GenerateBlock (replyTag, 32); // random session tag
			AddSessionKey (replyKey, replyTag);

			I2NPMessage * msg = WrapMessage (*nextFloodfill,
				CreateLeaseSetDatabaseLookupMsg (dest, request->excluded, 
					replyTunnel, replyKey, replyTag));
			outboundTunnel->SendTunnelDataMsg (
				{
					i2p::tunnel::TunnelMessageBlock 
					{ 
						i2p::tunnel::eDeliveryTypeRouter,
						nextFloodfill->GetIdentHash (), 0, msg
					}
				});	
			request->requestTimeoutTimer.expires_from_now (boost::posix_time::seconds(LEASESET_REQUEST_TIMEOUT));
			request->requestTimeoutTimer.async_wait (std::bind (&ClientDestination::HandleRequestTimoutTimer,
				this, std::placeholders::_1, dest));
		}	
		else
			return false;
		return true;
	}	

	void ClientDestination::HandleRequestTimoutTimer (const boost::system::error_code& ecode, const i2p::data::IdentHash& dest)
	{
		if (ecode != boost::asio::error::operation_aborted)
		{
			auto it = m_LeaseSetRequests.find (dest);
			if (it != m_LeaseSetRequests.end ())
			{
				bool done = false;
				uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
				if (ts < it->second->requestTime + MAX_LEASESET_REQUEST_TIMEOUT)
				{
					auto floodfill = i2p::data::netdb.GetClosestFloodfill (dest, it->second->excluded);
					if (floodfill)
						 SendLeaseSetRequest (dest, floodfill, it->second);
					else
						done = true;
				}
				else
				{	
					LogPrint (eLogInfo, dest.ToBase64 (), " was not found within ",  MAX_LEASESET_REQUEST_TIMEOUT, " seconds");
					done = true;
				}
				
				if (done)
				{
					if (it->second->requestComplete) it->second->requestComplete (false);
					delete it->second;
					m_LeaseSetRequests.erase (it);
				}	
			}	
		}	
	}	
}
}