###########################################################################
# Net::SIP::Simple::Call
# manages a call, contains Net::SIP::Endpoint::Context
# has hooks for some RTP handling
###########################################################################

use strict;
use warnings;

package Net::SIP::Simple::Call;
use base 'Net::SIP::Simple';
use fields qw( call_cleanup rtp_cleanup ctx param );

###########################################################################
# call_cleanup: callbacks for cleaning up call, called at the end
# rtp_cleanup: callbacks for cleaning up RTP connections, called
#   on reINVITEs and at the end
# ctx: Net::SIP::Endpoint::Context object for this call
# param: various parameter to control behavior
#   leg: thru which leg the call should be directed (default: first leg)
#   init_media: initialize handling for media (RTP) data, see
#    Net::SIP::Simple::RTP
#   sdp : predefined Net::SIP::SDP or data accepted from NET::SIP::SDP->new
#   media_lsocks: if sdp is provided the sockets has to be provided too
#     \@list of sockets for each media, each element in the list is
#     either the socket (udp) or [ rtp_socket,rtpc_socket ]
#   sdp_on_ack: send SDP data on ACK, not on INVITE
#   asymetric_rtp: socket for sending media to peer are not the same as
#      the sockets, where the media gets received, creates media_ssocks
#   media_ssocks: sockets used to send media to peer. If not given
#       and asymetric_rtp is used the sockets will be created, if not given
#       and not !asymetric_rtp media_lsocks will be used, e.g. symetric RTP
#   recv_bye: callback or scalar-ref used when call is closed by peer
#   send_bye: callback or scalar-ref used when call is closed by local side
#   sdp_peer: Net::SIP::SDP from peer
#   clear_sdp: ' causes that keys sdp,sdp_peer,media_ssocks and
#       media_lsocks gets cleared on new invite, so that a new SDP session
#       need to be established
#   cb_final: callback which will be called on final response in INVITE
#       with (status,self,%args) where status is OK|FAIL
#   cb_preliminary: callback which will be called on preliminary response
#       in INVITE with (self,code,packet)
#   cb_established: callback which will be called on receiving ACK in INVITE
#       with (status,self) where status is OK|FAIL
#   sip_header: hashref of SIP headers to add
#   call_on_hold: one-shot parameter to set local media addr to 0.0.0.0,
#       will be set to false after use
#   rtp_param: [ pt,size,interval,name ] RTP payload type, packet size and interval
#       between packets managed in Net::SIP::Simple::RTP, default is PCMU/8000,
#       e.g [ 0,160,160/8000 ]
#       a name can be added in which case an rtpmap and ptme entry will be created in the
#       SDP, e.g. [ 97,240,0.03,'iLBC/8000' ]
###########################################################################

use Net::SIP::Util qw(create_rtp_sockets invoke_callback);
use Net::SIP::Debug;
use Socket;
use Storable 'dclone';
use Carp 'croak';
use Scalar::Util 'weaken';

###########################################################################
# create a new call based on a controller
# Args: ($class,$control,$ctx;$param)
#   $control: Net::SIP::Simple object which controls this call
#   $ctx: SIP address of peer for new call or NET::SIP::Endpoint::Context
#        or hashref for constructing NET::SIP::Endpoint::Context
#   $param: see description of field 'param'
# Returns: $self
###########################################################################
sub new {
	my ($class,$control,$ctx,$param) = @_;
	my $self = fields::new( $class );
	%$self = %$control;
	$self->{ua_cleanup} = [];
	$self->{ctx} = ref($ctx) ? $ctx : {
		to => $ctx,
		from => $self->{from},
		contact => $self->{contact},
		auth => $self->{auth},
		route => $self->{route},
	};
	$self->{call_cleanup} = [];
	$self->{rtp_cleanup}  = [];
	$self->{param} = $param ||= {};
	$param->{init_media} ||= $self->rtp( 'media_recv_echo' );
	$param->{rtp_param}  ||= [ 0,160,160/8000 ]; # PCMU/8000: 5*160 bytes/second
	return $self;
}

###########################################################################
# Cleanups
# explicit cleanups might be necessary if callbacks reference back into
# the object so that it cannot be cleaned up by simple ref-counting alone
###########################################################################

sub cleanup {
	my Net::SIP::Simple::Call $self = shift;
	$self->rtp_cleanup;
	while ( my $cb = shift @{ $self->{call_cleanup} } ) {
		invoke_callback($cb,$self)
	}
	if ( my $ctx = $self->{ctx} ) {
		$self->{endpoint}->close_context( $ctx );
	}
	$self->{param} = {};
	$self->SUPER::cleanup;
}

sub rtp_cleanup {
	my Net::SIP::Simple::Call $self = shift;
	while ( my $cb = shift @{ $self->{rtp_cleanup} } ) {
		invoke_callback($cb,$self)
	}
	DEBUG( 100,"done" );
}

sub DESTROY {
	DEBUG( 100,"done" );
}


###########################################################################
# return peer of call
# Args: $self
# Returns: $peer
###########################################################################
sub get_peer {
	my Net::SIP::Simple::Call $self = shift;
	return $self->{ctx}->peer;
}

###########################################################################
# set parameter
# Args: ($self,%param)
# Returns: $self
###########################################################################
sub set_param {
	my Net::SIP::Simple::Call $self = shift;
	my %args = @_;
	@{ $self->{param} }{ keys %args } = values %args;
	return $self;
}

###########################################################################
# (Re-)Invite other party
# Args: ($self;%param)
#   %param: see description of field 'param', gets merged with param
#     already on object so that the values are valid for future use
# Returns: Net::SIP::Endpoint::Context
# Comment:
# If cb_final callback was not given it will loop until it got a final
# response, otherwise it will return immediatly
###########################################################################
sub reinvite {
	my Net::SIP::Simple::Call $self = shift;
	my %args = @_;

	my $param = $self->{param};
	my $clear_sdp = delete $args{clear_sdp};
	$clear_sdp = $param->{clear_sdp} if ! defined $clear_sdp;
	if ( $clear_sdp ) {
		# clear SDP keys so that a new SDP session will be created
		@{ $param }{qw( sdp _sdp_saved sdp_peer media_ssocks media_lsocks )} = ()
	}
	$self->{param} = $param = { %$param, %args } if %args;


	my $leg = $param->{leg};
	if ( ! $leg ) {
		($leg) = $self->{dispatcher}->get_legs();
		$param->{leg} = $leg;
	}

	my $ctx = $self->{ctx};

	my $sdp;
	if ( ! $param->{sdp_on_ack} ) {
		$self->_setup_local_rtp_socks;
		$sdp = $param->{sdp}
	}

	# predefined callback
	my $cb = sub {
		my Net::SIP::Simple::Call $self = shift || return;
		my ($endpoint,$ctx,$errno,$code,$packet,$leg,$from,$ack) = @_;

		if ( $errno ) {
			$self->error( "Failed with error $errno".( $code ? " code=$code" :"" ) );
			invoke_callback( $param->{cb_final}, 'FAIL',$self,errno => $errno,code => $code,packet => $packet );
			return;
		}

		# new requests in existing call are handled in receive()
		return $self->receive( @_ ) if $packet->is_request;

		# response to INVITE
		# all other responses will not be propagated to this callback
		my $param = $self->{param};
		if ( $code =~m{^1\d\d} ) {
			# preliminary response, ignore
			DEBUG(10,"got preliminary response of %s|%s to INVITE",$code,$packet->msg );
			invoke_callback( $param->{cb_preliminary},$self,$code,$packet );
			return;
		} elsif ( $code !~m{^2\d\d} ) {
			DEBUG(10,"got response of %s|%s to INVITE",$code,$packet->msg );
			invoke_callback( $param->{cb_final},'FAIL',$self,code => $code );
			return;
		}

		# cleanup RTP from last call
		$self->rtp_cleanup;

		$self->_setup_peer_rtp_socks( $packet ) || do {
			invoke_callback( $param->{cb_final},'FAIL',$self );
			return;
		};
		if ( $param->{sdp_on_ack} && $ack ) {
			$self->_setup_local_rtp_socks;
			$ack->set_body( $param->{sdp} );
		}
		invoke_callback( $param->{cb_final},'OK',$self );
		invoke_callback( $param->{init_media},$self,$param );
	};

	my $stopvar = 0;
	$param->{cb_final} ||= \$stopvar;
	$cb = [ $cb,$self ];
	weaken( $cb->[1] );
	$self->{ctx} = $self->{endpoint}->invite(
		$ctx, $cb, $sdp,
		$param->{sip_header} ? %{ $param->{sip_header} } : ()
	);
	if ( $param->{cb_final} == \$stopvar ) {
		# wait until final response
		$self->loop( \$stopvar );
		$param->{cb_final} = undef;
	}
	return $self->{ctx};
}


###########################################################################
# end call
# Args: ($self,%args)
#   %args:
#     cb_final: callback when BYE was delivered. If not given send_bye
#        callback on Call object will be used
# Returns: NONE
# Comment: cb_final gets triggered if the reply for the BYE is received
# or waiting for the reply timed out
###########################################################################
sub bye {
	my Net::SIP::Simple::Call $self = shift;
	my %args = @_;

	my $cb = delete $args{cb_final};
	%args = ( %{ $self->{param} }, %args );
	$cb ||= $args{send_bye};

	my $bye_cb = [
		sub {
			my Net::SIP::Simple::Call $self = shift || return;
			my ($cb,$args,$endpoint,$ctx,$error,$code) = @_;
			# we don't care about the cause of this callback
			# it might be a successful or failed reply packet or no reply
			# packet at all (timeout) - the call is considered closed
			# in any case except for 1xx responses
			# FIXME: should we check for 302 moved etc?
			if ( $code && $code =~m{^1\d\d} ) {
				DEBUG( 10,"got prelimary response for BYE" );
				return;
			}
			invoke_callback( $cb,$args );
			$self->cleanup;
		},
		$self,$cb,\%args
	];
	weaken( $bye_cb->[1] );

	$self->{endpoint}->new_request( 'BYE',$self->{ctx}, $bye_cb );
}

###########################################################################
# handle new packets within existing call
# Args: ($self,$endpoint,$ctx,$error,$code,$packet,$leg,$from)
#   $endpoint: the endpoint
#   $ctx: context for call
#   $error: errno if error occured
#   $code: code from responses
#   $packet: incoming packet
#   $leg: leg where packet came in
#   $from: addr from where packet came
# Returns: NONE
###########################################################################
sub receive {
	my ($self,$endpoint,$ctx,$error,$code,$packet,$leg,$from) = @_;
	if ( ! $packet ) {
		$self->error( "error occured: $error" );
	} elsif ( $packet->is_request ) {
		my $method = $packet->method;
		my $param = $self->{param};

		if ( $method eq 'BYE' || $method eq 'CANCEL' ) {
			# tear down
			$self->cleanup;
			invoke_callback( $param->{recv_bye},$param);
			# everything else already handled by Net::SIP::Endpoint::Context

		} elsif ( $method eq 'ACK' || $method eq 'INVITE' ) {

			# can transport sdp data
			if ( my $sdp_peer = $packet->sdp_body ) {
				DEBUG( 50,"got sdp data from peer: ".$sdp_peer->as_string );
				$self->_setup_peer_rtp_socks( $sdp_peer );
			}

			if ( $method eq 'INVITE' ) {

				if ( $param->{clear_sdp} ) {
					# clear SDP keys so that a new SDP session will be created
					@{ $param }{qw( sdp _sdp_saved sdp_peer media_ssocks media_lsocks )} = ()
				}

				$param->{leg} ||= $leg;
				$self->_setup_local_rtp_socks;

				# send 200 OK with sdp body
				my $response = $packet->create_response(
					'200','OK',{},$param->{sdp} );
				DEBUG( 100,'created response '.$response->as_string );
				$self->{endpoint}->new_response( $ctx,$response,$leg,$from );

			} elsif ( $method eq 'ACK' ) {
				$self->rtp_cleanup; # close last RTP session
				invoke_callback($param->{cb_established},'OK',$self);
				invoke_callback($param->{init_media},$self,$param);
			}

		} elsif ( $method eq 'OPTIONS' ) {

			my $response = $packet->create_response( '200','OK',$self->{options} );
			$self->{endpoint}->new_response( $ctx,$response,$leg,$from );
		}

	} else {
		# don't expect any responses.
		# Response to BYE is handled by Net::SIP::Endpoint::Context
		# other responses from the peer I don't expect
		DEBUG( 100,"got response. WHY? DROP." );
	}
}

###########################################################################
# setup $self->{param} for remote socks from remote SDP data
# Args: ($self,$data)
#   $data: packet containing sdp_body (Net::SIP::Packet) or
#     SDP data (Net::SIP::SDP)
# Returns: NONE
###########################################################################
sub _setup_peer_rtp_socks {
	my Net::SIP::Simple::Call $self = shift;
	my $param = $self->{param};
	my $data = shift || $param->{sdp_peer};

	my $sdp_peer;
	if ( UNIVERSAL::isa( $data, 'Net::SIP::Packet' )) {
		$sdp_peer = $data->sdp_body or do {
			$self->error( "No SDP body in packet" );
			return;
		};
	} else {
		$sdp_peer = $data
	}

	$param->{sdp_peer} = $sdp_peer;

	my @media = $sdp_peer->get_media;
	my $ls = $param->{media_lsocks};
	if ( $ls && @$ls && @media != @$ls ) {
		$self->error( "Unexpected number of media entries in SDP from peer" );
		return;
	}

	my $raddr = $param->{media_raddr} = [];
	my $null_address = pack( 'CCCC',0,0,0,0 ); # c=0.0.0.0 => call on hold
	foreach my $m (@media) {
		my $range = $m->{range} || 1;
		my $paddr = inet_aton( $m->{addr} );
		if ( $paddr eq $null_address ) {
			# on-hold for this media
			push @$raddr, undef;
		} else {
			my @socks = map { scalar(sockaddr_in( $m->{port}+$_ , $paddr )) }
				(0..$range-1);
			push @$raddr, @socks == 1 ? $socks[0] : \@socks;
		}
	}

	return 1;
}

###########################################################################
# setup local RTP socks
# Args: $self
# Returns: NONE
# Comments: set sdp,media_lsocks,media_ssocks in self->{param}
###########################################################################
sub _setup_local_rtp_socks {
	my Net::SIP::Simple::Call $self = shift;
	my $param = $self->{param};

	my $call_on_hold = $param->{call_on_hold};
	$param->{call_on_hold} = 0; # one-shot

	my $sdp = $param->{_sdp_saved} || $param->{sdp};
	if ( $sdp && !UNIVERSAL::isa( $sdp,'Net::SIP::SDP' )) {
		$sdp = Net::SIP::SDP->new( $sdp );
	}

	my $laddr = $param->{leg}{addr};
	if ( !$sdp ) {
		# create SDP body
		my $raddr = $param->{media_rsocks};

		# if no raddr yet just assume one
		my @media;
		if ( my $sdp_peer = $param->{sdp_peer} ) {
			foreach my $m ( $sdp_peer->get_media ) {
				if ( $m->{proto} ne 'RTP/AVP' ) {
					$self->error( "only RTP/AVP supported" );
					return;
				}
				if ( $m->{media} eq 'audio' ) {
					# enforce PCMU/8000 for now
					$m = { %$m, fmt => '0' }
				}
				push @media, {
					media => $m->{media},
					proto => $m->{proto},
					range => $m->{range},
					fmt   => $m->{fmt},
				};
			}
		} else {
			my $rp = $param->{rtp_param};
			push @media, {
				proto => 'RTP/AVP',
				media => 'audio',
				fmt   => $rp->[0] || 0, # PCMU/8000
				$rp->[3] ? ( 
					a => [ "rtpmap:$rp->[0] $rp->[3]" , "ptime:".$rp->[2]*1000 ]
				) :(),
			}
		}

		my $lsocks = $param->{media_lsocks} = [];
		foreach my $m (@media) {
			my ($port,@socks) = create_rtp_sockets( $laddr,$m->{range} )
				or die $!;
			push @$lsocks, @socks == 1 ? $socks[0] : \@socks;
			$m->{port} = $port;
		}

		$sdp = $param->{sdp} = Net::SIP::SDP->new(
			{ addr => $laddr },
			@media
		);
	}

	unless ( $param->{media_lsocks} ) {
		# SDP body was provided, but sockets not
		croak( 'not supported: if you provide SDP body you need to provide sockets too' );
	}

	# asymetric_rtp, e.g. source socket of packet to peer is not the socket where RTP
	# from peer gets received
	if ( !$param->{media_ssocks} && $param->{asymetric_rtp} ) {
		my @arg = (
			Proto => 'udp',
			LocalAddr => ( $param->{rtp_addr} || $laddr )
		);
		my $msocks = $param->{media_ssocks} = [];
		foreach my $m (@{ $param->{media_lsocks} }) {
			my $socks;
			if ( UNIVERSAL::isa( $m,'ARRAY' )) {
				$socks = [];
				foreach my $sock (@$m) {
					push @$socks, IO::Socket::INET->new(@arg) || die $!;
				}
			} else {
				$socks = IO::Socket::INET->new(@arg) || die $!;
			}
			push @$msocks,$socks;
		}
	}

	$param->{_sdp_saved} = $sdp;
	if ( $call_on_hold ) {
		$sdp = dclone($sdp); # make changes on clone
		my @new = map { [ '0.0.0.0',$_->{port} ] } $sdp->get_media;
		$sdp->replace_media_listen( @new );
		$param->{sdp} = $sdp;
	}
}

1;