//package tests;

import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.util.Calendar;
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;
import org.drools.runtime.StatefulKnowledgeSession;

public class EventStream {
	private float probabilityValue;
	private int symbol;
	private float price;
	private int volume;
	private float currValue;
	private StatefulKnowledgeSession ksession;
	public long counter = 1;
	public long old_counter = 1;
	
	private Random randGen1 = new Random(); // Default seed comes from system time.
	private Random randGen2 = new Random();
	private Random randGen3 = new Random();
	private Random randGen4 = new Random();
	public double global_duration = 1;
	public EventStream(){}
	public void register_session(StatefulKnowledgeSession _sess){ksession = _sess;}
	public StatefulKnowledgeSession get_working_session() { return ksession;}
	
	/**
	 * Generates synthetic event for a given duration time and probability for increasing stock price.
	 * @param duration	- Duration time in seconds (after which the method stops to generate events). If time==0, the method creates infinite event stream;
	 * @param p		- Probability for increasing stock price;
	 * @throws FileNotFoundException 
	 */
	void generateEventStream(double duration, double p)  {
		global_duration = duration;
		Timer counterTimer = new Timer();
		CounterRunner runner = new CounterRunner();
		counterTimer.schedule(runner,0,1000);
		Timer timer = new Timer();
		Stopper stopper = new Stopper();
		timer.schedule(stopper,(long)duration * 1000);
		try {
			 if(p < 0 || p > 1) throw new Exception();
        } catch (Exception e) {
        	System.err.println("Invalid parameter for probability p.");
			e.printStackTrace();
		}
        try{
			/*Increase, decrease or the same value of stocks are created by the following rule, for 0 =< p =< 1:
			if probabilityValue < p increase the stock value;
			if p < probabilityValue < (p+1)/2 decrease the stock value;
			if (p+1)/2 < probabilityValue < 1 the stock value remains the same;*/
			double decr = (p+1)/2;
			//Query query=new Query("retractall(logging(on))");
			//query.hasSolution();
			while(stopper.done() == 0){
				BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("ExpA.P",true)));
				symbol = randGen1.nextInt(2) + 1; // values: 1,2
				price = randGen2.nextInt(1000) + 1; // values: 1,2,...,1000
				volume = randGen3.nextInt(1000) + 1; // values: 1,2,...,1000
				probabilityValue = randGen4.nextFloat(); // values between 0 and 1
				if(probabilityValue < p){
					currValue = increase(price);
				}else if(probabilityValue > p && probabilityValue < decr){
					currValue = decrease(price);
				}else if(probabilityValue > decr){
					currValue = price;
				}
				Calendar ca = Calendar.getInstance();
				//String datime = "datime(" + ca.get(Calendar.YEAR) + "," + ( ca.get(Calendar.MONTH) + 1 ) + "," + ca.get(Calendar.DATE) + "," + ca.get(Calendar.HOUR_OF_DAY) + "," + ca.get(Calendar.MINUTE) + "," + ca.get(Calendar.SECOND) + "," + counter + ")";
				String datime = new String(""+counter);				
				//bw.append("event(stock(" + symbol + "," + currValue + "," + volume + "),[" + datime + "," + datime + "])"+".\n");
				bw.append("event(stock(" + symbol + "," + currValue + "),[" + datime + "," + datime + "])"+".\n");
				//Drools 
				Event temp = new Event(symbol,currValue);
				ksession.insert(temp);
				//
				//bw.append("event(systemClock(" + datime + "),[" + datime + "," + datime + "])"+".\n");
				//query=new Query("event(stock(" + symbol + "," + currValue + "," + volume + "),[" + datime + "," + datime + "])");
				//query.hasSolution();	
				counter++;
				bw.close();
			}
			counterTimer.cancel();
        } catch (Exception e) {
        	System.err.println("Exception: ");
			e.printStackTrace();
		}
	}
	
	private float increase(float currValue){
		return (float)(currValue + 0.1);
	}
	private float decrease(float currValue){
		return (float)(currValue - 0.1);
	}
	
	class CounterRunner extends TimerTask {
		public void run(){ //Print the number of events generated per second, typically  > 200 000,
			System.out.println("\nNo. of events/second is: " + (counter-old_counter) + ".\n");
			old_counter = counter;
	    }
	}
	class Stopper extends TimerTask {
		int finished = 0;
		public int done(){return this.finished;}
		public void run(){
			 //Print the number of events generated in total
			System.out.flush();
			System.out.println("\nNo. of events in total is: " + counter + ".");
			System.out.println("No. of total events/second is: " + (counter/global_duration));
			System.out.flush();
			// retrieve the results from Prolog
			//System.out.println("\n  Retrieve the results from Prolog: ");
			//Query queryRule=new Query("findall(eventFired(E),eventFired(E),L)");
			//Compound result = (Compound)(queryRule.oneSolution().get("L"));
			//System.out.println(result);					
			System.out.flush();
			this.finished = 1;    	
	    }
	}	
}