/**
 * NOTICE: This program was developed as part of a graduate-level project for my M.S. in Computer Science at the University of West Florida
 * 
 * Main Driver class for Collatz Sequence Project:
 * This program utilizes Threads to generate a Collatz sequence for numbers 2 to N and calculates the frequency of Collatz Stopping Times
 * 
 * @author Lorenzo Waguespack
 * @date 7/5/2020
 * @info Course COP5518 - University of West Florida
 * 
 */

package driver;

import java.time.Duration;
import java.time.Instant;
import java.util.ArrayList;

import threads.CThread;
import threads.ThreadData;

public class CollatzSeq {

	public static void main(String[] args) {
		CThread ct = new CThread();
		Instant start = Instant.now();
		Instant end;
		Duration diff;
		
		int usrRange = Integer.parseInt(args[0]);
		int usrThreads = Integer.parseInt(args[1]);
		
		ThreadData shared = new ThreadData(usrRange,usrThreads);
		ArrayList<Thread> threadList = new ArrayList<Thread>();
		
		for (int i=0; i<usrThreads; i++) {
			ct = new CThread("Thread"+(i+1),shared,usrRange);			//Adds thread to threadList based on number indicated by user
			threadList.add(ct);
		}
		
		for (Thread t:threadList) {
			t.start();
		}
		
		try {
			for (Thread t:threadList) {
				t.join();												//Joins threads once completed
			}
		}
		catch (Exception e) {
			System.err.println("Unable to join threads.");
		}
		
		int[] completeHist = shared.getHistogramArray();				//Return Histogram array and print frequencies to stdout from 1 to k (Largest stopping time)
		int k = shared.getLargestST();
		int freq;
		
		for (int s=0; s<k; s++) {
			freq = 0;
			
			for (int j=0; j<completeHist.length; j++) {
				if (completeHist[j] == (s+1)) {
					freq++;
				}
			}
			
			System.out.println("<" + (s + 1) + ">,<" + freq + ">");
		}
		
		end = Instant.now();											//Get the stopping time of the program to calculate total duration
		diff = Duration.between(start, end);
		
		System.out.println("\n");
		System.err.println(usrRange + "," + usrThreads + "," + diff.toSecondsPart() + "." + diff.toNanosPart());

	}

}