/**************************************************************
 * You can modify the template of this file in the
 * directory ..\JCreator\Templates\Template_1\Project_Name.java
 *
 * You can also create your own project template by making a new
 * folder in the directory ..\JCreator\Template\. Use the other
 * templates as examples.
 */

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.lang.Math;

class Nets1 extends Frame
{



	//________Parameters for simulation
	public static double alpha=.6;
	public static double beta=.8;
	public static int buffers=16; //____N+1 for infinite buffers___
	static int N=100000;
	static boolean commentary=false;

	//_______Other vars____
	public static double at[]=new double[N+2];
	public static double st[]=new double[N+2];
	public static double cat[]=new double[N+2];
	public static double cdt[]=new double[N+2];
	public static double idt[]=new double[N+2];
	public static int ql[]=new int[N+2];
	public static double tql=0;
	public static double pclock=0;
	public static int pql=0;

	
	public static int in,out;
	public static double nat,ndt,clock,dif;
	public static double talpha,tbeta;
	
	public static int customers_dropped=0;
	
	
	public Nets1()
	{
		
	}
	

	public static void main(String args[])
	{
		
		if(args.length<=3 && args.length>=2)
		{
			alpha=Double.parseDouble(args[0]);
			beta=Double.parseDouble(args[1]);
		}
		
		buffers=N+1;
		if(args.length==3)
			buffers=Integer.parseInt(args[2]);
			
			if(buffers==-1)
				buffers=N+1;
		
		
		print("\nInput Data ( M/M/1 Simulation )");
		print("-----------------------------------");
		print("\nArrival Rate ( lambda ) : " + alpha + "\nService Rate ( u ) : " + beta + "\nMaximum Queue Length : " + ((buffers==N+1) ? "Infinite" : (new Integer(buffers).toString())) + " \n \n");
		print("\n\nSimulation started");
		
		//____Computer at and st
		Random rnd=new Random();
		
			int i;
			
			double actualat=0,actualst=0;
		for(i=1;i<=N;i++)
		{
			
			at[i]=-Math.log(rnd.nextDouble())/alpha;
			actualat+=at[i];
			st[i]=-Math.log(rnd.nextDouble())/beta;
			actualst+=st[i];
		}
		
		
		double averageat=actualat/N;
		double averagest=actualst/N;
		
		talpha=alpha;
		alpha=1.0/averageat;
		tbeta=beta;
		beta=1.0/averagest;
		
		
		
		
		//_____Start the simulation____
		at[1]=0;
		cat[0]=0;
		for(i=1;i<=N;i++)
		{
			cat[i]=cat[i-1]+at[i];
			idt[i]=ql[i]=0;
		}
		
		ql[N+1]=0;
		in=2; out=1;
		nat=cat[2];
		ndt=cdt[1]=st[1];
		clock=0;
		
		
		if(commentary)
			print("Arrival at : 0");
			
			
		while(out<=N)
		{
			if(in<=N) //______still arrivals are left
			{
				dif=nat-ndt; //__see arrival or departure ?
				if(dif<0) //___arrival
				{
					if(commentary)
						print("Arrival at : " + nat);

					
					if(ql[in-1]>=buffers)
					{
						if(commentary)
							print("Customer dropped !");
						
						customers_dropped++;
						st[in]=0;
						ql[in]=buffers;
					
						
					}
					else
						ql[in]=in-out;
					
					
					tql+=pql*(clock-pclock);
					
					pclock=clock;
					pql=in-out-1;	
					
			//		print("  "  + tql);


					
					clock=nat;
					nat=cat[in+1];
					
					in++;
					continue;
				}
				else if(dif>0) //____departure
				{
					if(in-out>1) //___queue is not empty
					{
			
						tql+=pql*(clock-pclock);
					
						pclock=clock;
						pql=in-out-1;	

				//	print("  "  + tql);

						clock=ndt;
					if(commentary && !iszero(st[out]))
						print("Departure at : " + clock);
						


						cdt[out+1]=cdt[out]+st[out+1];
						ndt=cdt[out+1];
						out++;
					}
					else //___queue is empty
					{
						idt[in]=dif;

						if(commentary && !iszero(st[out]))
						
							print("Departure at : " + ndt);


					tql+=pql*(clock-pclock);
					
					pclock=clock;
					pql=in-out-1;	

				//	print("  "  + tql);

						clock=nat;
						if(commentary)
						{
							print("Server is idle for : " + dif);
							print("Arrival at : " + clock);
						}


						nat=cat[in+1];
						cdt[out+1]=cat[in]+st[out+1];
						ndt=cdt[out+1];
						out++;
						in++;
					}
				}
				else if(iszero(dif))
				{
						ql[in]=ql[in-1];


					tql+=pql*(clock-pclock);
					
					pclock=clock;
					pql=in-out-1;	
					
				//	print("  "  + tql);

						clock=nat;

						if(commentary)
						{

							if(!iszero(st[out]))
								print("Departure at : " + clock);
							print("Arrival at : " + clock);
						}
						
						nat=cat[in+1];
						cdt[out+1]=cat[in]+st[out+1];
						ndt=cdt[out+1];
						out++;
						in++;
				
				}
			}
			else //___All arrivals have exhausted
			{

					tql+=pql*(clock-pclock);
					
					pclock=clock;
					pql=in-out-1;	
				//	print("  "  + tql);


				clock=ndt;
				if(commentary && !iszero(st[out]))
					print("Departure at : " + clock);

				cdt[out+1]=cdt[out]+st[out+1];
				ndt=cdt[out+1];
				out++;
			}
				
		}

		//____Print statistics
		
		
		print("Simulation Finished");

		double tot_waiting,max_waiting,tot_idle,tot_time;
		int non_zero_ele,que_len,max_que;
		
		que_len=max_que=ql[1];
		tot_waiting=max_waiting=cdt[1]-cat[1]-st[1];
		if(st[1]==0)
			tot_waiting=max_waiting=0;
		
		tot_time=cdt[1]-cat[1];
		if(st[1]==0)
			tot_time=0;
		
		tot_idle=idt[1];
		non_zero_ele=0;

		double taq=0;
	
		for( i = 2;i<=N;i++)
		{
			que_len+=ql[i];
			{
				if(i>3*N/4)
					taq+=(ql[i-1])*(cat[i]-cat[i-1]);
			}
			
			if(max_que<ql[i])
				max_que=ql[i];
				
			if(ql[i]!=0)
				non_zero_ele++;
			tot_idle+=idt[i];
		
			double ttime=cdt[i]-cat[i];
			if(st[i]==0)
				ttime=0;
			tot_time+=ttime;
			
			//____Don't add waiting times for dropped packets
			double wtime=cdt[i]-cat[i]-st[i];
			if(st[i]==0) 
				wtime=0;
			tot_waiting+=wtime;
			
			if(max_waiting<(wtime))
			max_waiting=wtime;
		}

	//	taq+=ql[N]*(cdt[N]-cat[N]);

		
		printtheory(tot_time,taq,tot_waiting);

		print(" ");
		print(" ");

		print("\nOther statistics\n--------------------");
		System.out.println("The average length of a non-empty queue is " + (((double)(que_len))/non_zero_ele));
		System.out.println("The maximum length of a queue is "+max_que);
		System.out.println("The maximum waiting time of a customer is " + max_waiting);
		System.out.println("The total idle time of the server is " + tot_idle);
		System.out.println("No. of Packets dropped are : " + customers_dropped);
		
		System.out.flush();

	}
				
	
	static void print(String s)
	{
		System.out.println(s);
		System.out.flush();
				

	}
	
	static boolean iszero(double d)
	{
		if(d<0.0001)
			return true;
			
		return false;
	}
	
	static void printtheory(double tot_time,double taq,double tot_waiting)
	{
		double ro=alpha/beta;
		print("\n \n \nResults");
		print("--------------------");
		print("Theoretical Arrival Rate : " + talpha + "   Actual :" + alpha);
		print("Theoretical Service Rate : " + tbeta + "   Actual :" +beta);
			
		print("Average time spent by a customer (delay)\nTheoretical : " + 1.00/(beta-alpha) + " Simulation Result : " + (tot_time/(N-customers_dropped)));
//		print("Average queue length\nTheoretical : " + ro*ro/(1.0-ro)+ " Simulation result : " + (((double)(que_len))/N));
//		print("Average queue length\nTheoretical : " + ro*ro/(1.0-ro)+ " Simulation result : " + (taq)/(cat[N]-cat[3*N/4]));
		print("Average queue length\nTheoretical : " + ro*ro/(1.0-ro)+ " Simulation result : " + tql/pclock);
		
		


		print("Average Waiting time\nTheoretical : " + ro/(beta-alpha) + " Simulation result : " + (tot_waiting/(N-customers_dropped)));
		
	
		
	}
	
						
		
	
}