//  Author: Leslie S. Liu (shihuali@usc.edu)
//  Written on April 22, 2003
//  IMSC , University of Southern California
//  File:      pp-app.h
//  Written for : ns-2.26
//  Last updated: April 23, 2003
//

#include "timer-handler.h"
#include "packet.h"
#include "app.h"
#include "udp-pp.h"

#define MAX_NODE_NUM 256 // maximum peers allowed to connect to each node
#define MAX_DELAY    200 // set maximum delay in ms
#define MAX_DEGREE   3   // set the maximum node allowed to connect

// This is used for receiver's received packet accounting
struct pkt_accounting { 
        int last_seq;   // sequence number of last received PP pkt
        int last_scale; // rate (0-4) of last acked
        int lost_pkts;  // number of lost pkts since last ack
        int recv_pkts;  // number of received pkts since last ack
        double rtt;     // round trip time
};


class PPApp;


// Sender uses this timer to 
// schedule next voice data packet transmission time
// if the node is in talking mode
class SendVoiceTimer : public TimerHandler {
 public:
	SendVoiceTimer(PPApp* t) : TimerHandler() {t_=t;}
	inline virtual void expire(Event*);
 protected:
	PPApp* t_;
};


//Nodes  this timer to schedule
// next checking  time for connection failure
class CheckTimer : public TimerHandler {
 public:
	CheckTimer(PPApp* t) : TimerHandler(), t_(t) {}
	inline virtual void expire(Event*);
 protected:
	PPApp* t_;
};


// PeerToPeer Application Class Definition
class PPApp : public Application {
 public:
	PPApp();
	void send_voice_pkt();  // called by SendVoiceTimer:expire to 
       				// deliver the voice stream	
	void send_check_pkt();  // called by CheckTimer:expire for 
			        // unexpected failure of connection
      
	//list of address of connected nodes
	nsaddr_t peerlist[MAX_DEGREE]; //maximum allowed  peers
	int peer_n ;  			 //current connected peer number
	int next_slot();		 //return the next available slot for join

	//Categories of nodes
	int core;    		// value==1 if the node is core
	int RP;			// value==1 if the node is Rendezvous Point
	int firstpeer;		// value==1 if the node is First Peer(nodes that
				// directly connecte to core)
	int leaf;		// value==1 if the node is leaf node
	int normal;		// value==1 if the node is not a special node
				// named above
	
	//Important outer nodes
	nsaddr_t parent_node;	// Address of parent node in the CBT
	nsaddr_t core_node;	// Address of core in case of need
	nsaddr_t bk_node;	// Address of a backup node, this node maybe 
				// the same as the parent_node and not
				// guarantee to serve as backup
	
 protected:
	int command(int argc, const char*const* argv);
	void start();       	// Start running the program
	void stop();        	// Stop running the program 
	void join();        	// Try to Join the nodes that conencted to, 
			    	// it could be RP but also can be other nodes
				// The node will start receiving voice stream
				//
	void leave();	    	// leave the CBT group, but keep the program running,
			    	// this is almost the same as stop() except that 
		            	// once a node stopped, it need to call start() again
			    	// before it can join() 
				// 
	//Start talking and keep it on for t_time for simulation purpose.
	void talk(double t_time);	
	
 private:
        //status of the node
	int running_;		// value ==1 if the program is running, 
				// set by start()	
	int talking_; 		// value ==1 if the user of this node is
				// talking, set by talk()
	int joined_;		// value ==1 if the node has joined in the
				// chatting group

	//Parameters of the network
	int pktsize_;          // Application data packet size
	double rate[5];        // Transmission rates associated to scale values
	int scale_;            // Media scale parameter
	double interval_;      // Time needed to complete one packet transmission
	double t_timeover;     // If talking==1 , it shows time  that a user need to stop
			       // talking (this is used to simplify simulation)
	int random_;           // If 1 add randomness to the interval
	int seq_;              // Application data packet sequence number

	//functions
	//Major function 	
	virtual void recv_msg(int nbytes, const char *msg = 0); // called when there is 
       								// new packet coming	
	//Miscellaneous functions
	void init();
	inline double next_snd_time();                          // next time to send out
								// the voice packets
								//
	void set_scale(const hdr_pp *mh_buf);                   // dynamically ajust the
								// the connecton speed
	void adjust_scale(void);				// (only a place holder now)
								//	
	void account_recv_pkt(const hdr_pp *mh_buf);            // Statistic function
	void init_recv_pkt_accounting();                        // (only a place holder now) 

	void print_peer();					//print out current peer
	
	//statisitic variable
	pkt_accounting p_accnt;


	//Timer
	SendVoiceTimer snd_timer_;  				// SendVoiceTimer
	CheckTimer  chk_timer_;  				// CheckTimer
};