//  Author: Leslie S. Liu (shihuali@usc.edu)
//  Written on April 22, 2003
//  IMSC , University of Southern California
//  Original Author:    Jae Chung  (udp-mm.cc)
//  File:      udp-pp.cc
//  Written for : ns-2.26
//   


#include "udp-pp.h"
#include "rtp.h"
#include "random.h"
#include <string.h>


int hdr_pp::offset_;

// Mulitmedia Header Class 
static class P2PHeaderClass : public PacketHeaderClass {
public:
	P2PHeaderClass() : PacketHeaderClass("PacketHeader/P2P",
						    sizeof(hdr_pp)) {
		bind_offset(&hdr_pp::offset_);
	}
} class_pphdr;


// UdpPPAgent OTcl linkage class
static class UdpPPAgentClass : public TclClass {
public:
	UdpPPAgentClass() : TclClass("Agent/UDP/UDPpp") {}
	TclObject* create(int, const char*const*) {
		return (new UdpPPAgent());
	}
} class_udppp_agent;


// Constructor (with no arg)
UdpPPAgent::UdpPPAgent() : UdpAgent()
{
	support_pp_ = 0;
	asm_info.seq = -1;
}

UdpPPAgent::UdpPPAgent(packet_t type) : UdpAgent(type)
{
	support_pp_ = 0;
	asm_info.seq = -1;
}


// Add Support of P2P Application to UdpAgent::sendmsg
void UdpPPAgent::sendmsg(int nbytes, const char* flags)
{
	Packet *p;
	int n, remain;

	if (size_) {
		n = (nbytes/size_ + (nbytes%size_ ? 1 : 0));
		remain = nbytes%size_;
	}
	else
		printf("Error: UDPpp size = 0\n");

	if (nbytes == -1) {
		printf("Error:  sendmsg() for UDPpp should not be -1\n");
		return;
	}
	double local_time =Scheduler::instance().clock();
	while (n-- > 0) {
		p = allocpkt();
		if(n==0 && remain>0) hdr_cmn::access(p)->size() = remain;
		else hdr_cmn::access(p)->size() = size_;
		hdr_rtp* rh = hdr_rtp::access(p);
		rh->flags() = 0;
		rh->seqno() = ++seqno_;
		hdr_cmn::access(p)->timestamp() = 
		    (u_int32_t)(SAMPLERATE*local_time);
		// to eliminate recv to use PP fields for non PP packets
		hdr_pp* mh = hdr_pp::access(p);
		//mh->ack = 0;
		mh->seq = 0;
		mh->nbytes = 0;
		mh->time = 0;
		mh->scale = 0;
		// pp udp packets are distinguished by setting the ip
		// priority bit to 15 (Max Priority).
		if(support_pp_) {
			hdr_ip* ih = hdr_ip::access(p);
			hdr_pp* ph_buf=(hdr_pp*) flags;
			ih->prio_ = 15;
			if(ph_buf->v_data==1) //this is a voice packet
			{
				ih->fid_=3;		//color of data stream
			}
			if(flags) // PP Seq Num is passed as flags
			{
				memcpy(mh, flags, sizeof(hdr_pp));
			}

		}
		// add "beginning of talkspurt" labels (tcl/ex/test-rcvr.tcl)
		if (flags && (0 ==strcmp(flags, "NEW_BURST")))
			rh->flags() |= RTP_M;
		
		target_->recv(p);
	}
	idle();
}


// Support Packet Re-Assembly and P2P Application
void UdpPPAgent::recv(Packet* p, Handler*)
{
	hdr_ip* ih = hdr_ip::access(p);
	int bytes_to_deliver = hdr_cmn::access(p)->size();
	// if it is a PP packet (data or ack)
	if(ih->prio_ == 15) { 
		if(app_) {  // if PP Application exists
			// re-assemble PP Application packet if segmented
			hdr_pp* mh = hdr_pp::access(p);
			printf("[NETWORK] UDP transport P2P packet from addr_(%d) to addr_(%d)\n",ih->saddr(),ih->daddr());
	   	        //printf("PPAnget::recv: local seq= %d and packet seq= %d \n",asm_info.seq, mh->seq);
			if(mh->seq == asm_info.seq)
				asm_info.rbytes += hdr_cmn::access(p)->size();
			else {
				asm_info.seq = mh->seq;
				asm_info.tbytes = mh->nbytes;
				asm_info.rbytes = hdr_cmn::access(p)->size();
			}
			// if fully reassembled, pass the packet to applicatio
	   	        //printf("PPAnget::recv: rbytes= %d and tbytes= %d \n",asm_info.rbytes, asm_info.tbytes);
			if(asm_info.tbytes == asm_info.rbytes) {
				hdr_pp mh_buf;
				memcpy(&mh_buf, mh, sizeof(hdr_pp));
			//	printf("PPAnget::recv: pass P2P gpacket up to application level\n");
				app_->recv_msg(mh_buf.nbytes, (char*) &mh_buf);
				//now clear up the asm_info for future packet
				asm_info.seq=-1;
			}
		}
		Packet::free(p);
	}
	// if it is a normal data packet (not PP data or ack packet)
	else { 
		//printf("PPAgent::recv(): Just a normal packet\n");
		if (app_) app_->recv(bytes_to_deliver);
		Packet::free(p);
	}
}