/*
	oscpack -- Open Sound Control packet manipulation library
	http://www.audiomulch.com/~rossb/oscpack

	Copyright (c) 2004-2005 Ross Bencina <rossb@audiomulch.com>

	Permission is hereby granted, free of charge, to any person obtaining
	a copy of this software and associated documentation files
	(the "Software"), to deal in the Software without restriction,
	including without limitation the rights to use, copy, modify, merge,
	publish, distribute, sublicense, and/or sell copies of the Software,
	and to permit persons to whom the Software is furnished to do so,
	subject to the following conditions:

	The above copyright notice and this permission notice shall be
	included in all copies or substantial portions of the Software.

	Any person wishing to distribute modifications to the Software is
	requested to send the modifications to the original developer so that
	they can be incorporated into the canonical version.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
	IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
	ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
	CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
	WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "ip/UdpSocket.h"

#include <winsock2.h>   // this must come first to prevent errors with MSVC7
#include <windows.h>
#include <mmsystem.h>   // for timeGetTime()

#include <vector>
#include <algorithm>
#include <stdexcept>
#include <assert.h>
#include <signal.h>

#include "ip/NetworkingUtils.h"
#include "ip/PacketListener.h"
#include "ip/TimerListener.h"


typedef int socklen_t;


static void SockaddrFromIpEndpointName( struct sockaddr_in& sockAddr, const IpEndpointName& endpoint )
{
    memset( (char *)&sockAddr, 0, sizeof(sockAddr ) );
    sockAddr.sin_family = AF_INET;

	sockAddr.sin_addr.s_addr = 
		(endpoint.address == IpEndpointName::ANY_ADDRESS)
		? INADDR_ANY
		: htonl( endpoint.address );

	sockAddr.sin_port =
		(endpoint.port == IpEndpointName::ANY_PORT)
		? (short)0
		: htons( (short)endpoint.port );
}


static IpEndpointName IpEndpointNameFromSockaddr( const struct sockaddr_in& sockAddr )
{
	return IpEndpointName( 
		(sockAddr.sin_addr.s_addr == INADDR_ANY) 
			? IpEndpointName::ANY_ADDRESS 
			: ntohl( sockAddr.sin_addr.s_addr ),
		(sockAddr.sin_port == 0)
			? IpEndpointName::ANY_PORT
			: ntohs( sockAddr.sin_port )
		);
}


class UdpSocket::Implementation{
    NetworkInitializer networkInitializer_;

	bool isBound_;
	bool isConnected_;

	SOCKET socket_;
	struct sockaddr_in connectedAddr_;
	struct sockaddr_in sendToAddr_;

public:

	Implementation()
		: isBound_( false )
		, isConnected_( false )
		, socket_( INVALID_SOCKET )
	{
		if( (socket_ = socket( AF_INET, SOCK_DGRAM, 0 )) == INVALID_SOCKET ){
            throw std::runtime_error("unable to create udp socket\n");
        }

		memset( &sendToAddr_, 0, sizeof(sendToAddr_) );
        sendToAddr_.sin_family = AF_INET;
	}

	~Implementation()
	{
		if (socket_ != INVALID_SOCKET) closesocket(socket_);
	}

	IpEndpointName LocalEndpointFor( const IpEndpointName& remoteEndpoint ) const
	{
		assert( isBound_ );

		// first connect the socket to the remote server
        
        struct sockaddr_in connectSockAddr;
		SockaddrFromIpEndpointName( connectSockAddr, remoteEndpoint );
       
        if (connect(socket_, (struct sockaddr *)&connectSockAddr, sizeof(connectSockAddr)) < 0) {
            throw std::runtime_error("unable to connect udp socket\n");
        }

        // get the address

        struct sockaddr_in sockAddr;
        memset( (char *)&sockAddr, 0, sizeof(sockAddr ) );
        socklen_t length = sizeof(sockAddr);
        if (getsockname(socket_, (struct sockaddr *)&sockAddr, &length) < 0) {
            throw std::runtime_error("unable to getsockname\n");
        }
        
		if ( isConnected_ ) {
			// reconnect to the connected address
			
			if (connect(socket_, (struct sockaddr *)&connectedAddr_, sizeof(connectedAddr_)) < 0) {
				throw std::runtime_error("unable to connect udp socket\n");
			}

		} else{
			// unconnect from the remote address
		
			struct sockaddr_in unconnectSockAddr;
			SockaddrFromIpEndpointName( unconnectSockAddr, IpEndpointName() );

			if( connect(socket_, (struct sockaddr *)&unconnectSockAddr, sizeof(unconnectSockAddr)) < 0 
					&& WSAGetLastError() != WSAEADDRNOTAVAIL ){
				throw std::runtime_error("unable to un-connect udp socket\n");
			}
		}

		return IpEndpointNameFromSockaddr( sockAddr );
	}

	void Connect( const IpEndpointName& remoteEndpoint )
	{
		SockaddrFromIpEndpointName( connectedAddr_, remoteEndpoint );
       
        if (connect(socket_, (struct sockaddr *)&connectedAddr_, sizeof(connectedAddr_)) < 0) {
            throw std::runtime_error("unable to connect udp socket\n");
        }

		isConnected_ = true;
	}

	void Send( const char *data, int size )
	{
		assert( isConnected_ );

        send( socket_, data, size, 0 );
	}

    void SendTo( const IpEndpointName& remoteEndpoint, const char *data, int size )
	{
		sendToAddr_.sin_addr.s_addr = htonl( remoteEndpoint.address );
        sendToAddr_.sin_port = htons( (short)remoteEndpoint.port );

        sendto( socket_, data, size, 0, (sockaddr*)&sendToAddr_, sizeof(sendToAddr_) );
	}

	void Bind( const IpEndpointName& localEndpoint )
	{
		struct sockaddr_in bindSockAddr;
		SockaddrFromIpEndpointName( bindSockAddr, localEndpoint );

        if (bind(socket_, (struct sockaddr *)&bindSockAddr, sizeof(bindSockAddr)) < 0) {
            throw std::runtime_error("unable to bind udp socket\n");
        }

		isBound_ = true;
	}

	bool IsBound() const { return isBound_; }

    int ReceiveFrom( IpEndpointName& remoteEndpoint, char *data, int size )
	{
		assert( isBound_ );

		struct sockaddr_in fromAddr;
        socklen_t fromAddrLen = sizeof(fromAddr);
             	 
        int result = recvfrom(socket_, data, size, 0,
                    (struct sockaddr *) &fromAddr, (socklen_t*)&fromAddrLen);
		if( result < 0 )
			return 0;

		remoteEndpoint.address = ntohl(fromAddr.sin_addr.s_addr);
		remoteEndpoint.port = ntohs(fromAddr.sin_port);

		return result;
	}

	SOCKET& Socket() { return socket_; }
};

UdpSocket::UdpSocket()
{
	impl_ = new Implementation();
}

UdpSocket::~UdpSocket()
{
	delete impl_;
}

IpEndpointName UdpSocket::LocalEndpointFor( const IpEndpointName& remoteEndpoint ) const
{
	return impl_->LocalEndpointFor( remoteEndpoint );
}

void UdpSocket::Connect( const IpEndpointName& remoteEndpoint )
{
	impl_->Connect( remoteEndpoint );
}

void UdpSocket::Send( const char *data, int size )
{
	impl_->Send( data, size );
}

void UdpSocket::SendTo( const IpEndpointName& remoteEndpoint, const char *data, int size )
{
	impl_->SendTo( remoteEndpoint, data, size );
}

void UdpSocket::Bind( const IpEndpointName& localEndpoint )
{
	impl_->Bind( localEndpoint );
}

bool UdpSocket::IsBound() const
{
	return impl_->IsBound();
}

int UdpSocket::ReceiveFrom( IpEndpointName& remoteEndpoint, char *data, int size )
{
	return impl_->ReceiveFrom( remoteEndpoint, data, size );
}


struct AttachedTimerListener{
	AttachedTimerListener( int id, int p, TimerListener *tl )
		: initialDelayMs( id )
		, periodMs( p )
		, listener( tl ) {}
	int initialDelayMs;
	int periodMs;
	TimerListener *listener;
};


static bool CompareScheduledTimerCalls( 
		const std::pair< double, AttachedTimerListener > & lhs, const std::pair< double, AttachedTimerListener > & rhs )
{
	return lhs.first < rhs.first;
}


SocketReceiveMultiplexer *multiplexerInstanceToAbortWithSigInt_ = 0;

extern "C" /*static*/ void InterruptSignalHandler( int );
/*static*/ void InterruptSignalHandler( int )
{
	multiplexerInstanceToAbortWithSigInt_->AsynchronousBreak();
	signal( SIGINT, SIG_DFL );
}


class SocketReceiveMultiplexer::Implementation{
    NetworkInitializer networkInitializer_;

	std::vector< std::pair< PacketListener*, UdpSocket* > > socketListeners_;
	std::vector< AttachedTimerListener > timerListeners_;

	volatile bool break_;
	HANDLE breakEvent_;

	double GetCurrentTimeMs() const
	{
		return timeGetTime(); // FIXME: bad choice if you want to run for more than 40 days
	}

public:
    Implementation()
	{
		breakEvent_ = CreateEvent( NULL, FALSE, FALSE, NULL );
	}

    ~Implementation()
	{
		CloseHandle( breakEvent_ );
	}

    void AttachSocketListener( UdpSocket *socket, PacketListener *listener )
	{
		assert( std::find( socketListeners_.begin(), socketListeners_.end(), std::make_pair(listener, socket) ) == socketListeners_.end() );
		// we don't check that the same socket has been added multiple times, even though this is an error
		socketListeners_.push_back( std::make_pair( listener, socket ) );
	}

    void DetachSocketListener( UdpSocket *socket, PacketListener *listener )
	{
		std::vector< std::pair< PacketListener*, UdpSocket* > >::iterator i = 
				std::find( socketListeners_.begin(), socketListeners_.end(), std::make_pair(listener, socket) );
		assert( i != socketListeners_.end() );

		socketListeners_.erase( i );
	}

    void AttachPeriodicTimerListener( int periodMilliseconds, TimerListener *listener )
	{
		timerListeners_.push_back( AttachedTimerListener( periodMilliseconds, periodMilliseconds, listener ) );
	}

	void AttachPeriodicTimerListener( int initialDelayMilliseconds, int periodMilliseconds, TimerListener *listener )
	{
		timerListeners_.push_back( AttachedTimerListener( initialDelayMilliseconds, periodMilliseconds, listener ) );
	}

    void DetachPeriodicTimerListener( TimerListener *listener )
	{
		std::vector< AttachedTimerListener >::iterator i = timerListeners_.begin();
		while( i != timerListeners_.end() ){
			if( i->listener == listener )
				break;
			++i;
		}

		assert( i != timerListeners_.end() );

		timerListeners_.erase( i );
	}

    void Run()
	{
		break_ = false;

		// prepare the window events which we use to wake up on incoming data
		// we use this instead of select() primarily to support the AsyncBreak() 
		// mechanism.

		std::vector<HANDLE> events( socketListeners_.size() + 1, 0 );
		int j=0;
		for( std::vector< std::pair< PacketListener*, UdpSocket* > >::iterator i = socketListeners_.begin();
				i != socketListeners_.end(); ++i, ++j ){

			HANDLE event = CreateEvent( NULL, FALSE, FALSE, NULL );
			WSAEventSelect( i->second->impl_->Socket(), event, FD_READ ); // note that this makes the socket non-blocking which is why we can safely call RecieveFrom() on all sockets below
			events[j] = event;
		}


		events[ socketListeners_.size() ] = breakEvent_; // last event in the collection is the break event

		
		// configure the timer queue
		double currentTimeMs = GetCurrentTimeMs();

		// expiry time ms, listener
		std::vector< std::pair< double, AttachedTimerListener > > timerQueue_;
		for( std::vector< AttachedTimerListener >::iterator i = timerListeners_.begin();
				i != timerListeners_.end(); ++i )
			timerQueue_.push_back( std::make_pair( currentTimeMs + i->initialDelayMs, *i ) );
		std::sort( timerQueue_.begin(), timerQueue_.end(), CompareScheduledTimerCalls );

		const int MAX_BUFFER_SIZE = 4098;
		char *data = new char[ MAX_BUFFER_SIZE ];
		IpEndpointName remoteEndpoint;

		while( !break_ ){

			double currentTimeMs = GetCurrentTimeMs();

            DWORD waitTime = INFINITE;
            if( !timerQueue_.empty() ){

                waitTime = (DWORD)( timerQueue_.front().first >= currentTimeMs
                            ? timerQueue_.front().first - currentTimeMs
                            : 0 );
            }

			DWORD waitResult = WaitForMultipleObjects( (DWORD)socketListeners_.size() + 1, &events[0], FALSE, waitTime );
			if( break_ )
				break;

			if( waitResult != WAIT_TIMEOUT ){
				for( int i = waitResult - WAIT_OBJECT_0; i < (int)socketListeners_.size(); ++i ){
					int size = socketListeners_[i].second->ReceiveFrom( remoteEndpoint, data, MAX_BUFFER_SIZE );
					if( size > 0 ){
						socketListeners_[i].first->ProcessPacket( data, size, remoteEndpoint );
						if( break_ )
							break;
					}
				}
			}

			// execute any expired timers
			currentTimeMs = GetCurrentTimeMs();
			bool resort = false;
			for( std::vector< std::pair< double, AttachedTimerListener > >::iterator i = timerQueue_.begin();
					i != timerQueue_.end() && i->first <= currentTimeMs; ++i ){

				i->second.listener->TimerExpired();
				if( break_ )
					break;

				i->first += i->second.periodMs;
				resort = true;
			}
			if( resort )
				std::sort( timerQueue_.begin(), timerQueue_.end(), CompareScheduledTimerCalls );
		}

		delete [] data;

		// free events
		j = 0;
		for( std::vector< std::pair< PacketListener*, UdpSocket* > >::iterator i = socketListeners_.begin();
				i != socketListeners_.end(); ++i, ++j ){

			WSAEventSelect( i->second->impl_->Socket(), events[j], 0 ); // remove association between socket and event
			CloseHandle( events[j] );
			unsigned long enableNonblocking = 0;
			ioctlsocket( i->second->impl_->Socket(), FIONBIO, &enableNonblocking );  // make the socket blocking again
		}
	}

    void Break()
	{
		break_ = true;
	}

    void AsynchronousBreak()
	{
		break_ = true;
		SetEvent( breakEvent_ );
	}
};



SocketReceiveMultiplexer::SocketReceiveMultiplexer()
{
	impl_ = new Implementation();
}

SocketReceiveMultiplexer::~SocketReceiveMultiplexer()
{	
	delete impl_;
}

void SocketReceiveMultiplexer::AttachSocketListener( UdpSocket *socket, PacketListener *listener )
{
	impl_->AttachSocketListener( socket, listener );
}

void SocketReceiveMultiplexer::DetachSocketListener( UdpSocket *socket, PacketListener *listener )
{
	impl_->DetachSocketListener( socket, listener );
}

void SocketReceiveMultiplexer::AttachPeriodicTimerListener( int periodMilliseconds, TimerListener *listener )
{
	impl_->AttachPeriodicTimerListener( periodMilliseconds, listener );
}

void SocketReceiveMultiplexer::AttachPeriodicTimerListener( int initialDelayMilliseconds, int periodMilliseconds, TimerListener *listener )
{
	impl_->AttachPeriodicTimerListener( initialDelayMilliseconds, periodMilliseconds, listener );
}

void SocketReceiveMultiplexer::DetachPeriodicTimerListener( TimerListener *listener )
{
	impl_->DetachPeriodicTimerListener( listener );
}

void SocketReceiveMultiplexer::Run()
{
	impl_->Run();
}

void SocketReceiveMultiplexer::RunUntilSigInt()
{
	assert( multiplexerInstanceToAbortWithSigInt_ == 0 ); /* at present we support only one multiplexer instance running until sig int */
	multiplexerInstanceToAbortWithSigInt_ = this;
	signal( SIGINT, InterruptSignalHandler );
	impl_->Run();
	signal( SIGINT, SIG_DFL );
	multiplexerInstanceToAbortWithSigInt_ = 0;
}

void SocketReceiveMultiplexer::Break()
{
	impl_->Break();
}

void SocketReceiveMultiplexer::AsynchronousBreak()
{
	impl_->AsynchronousBreak();
}

