package be.ac.vub.ir.multithreading;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import javax.swing.JFileChooser;

import flanagan.math.Fmath;

import be.ac.vub.ir.util.Chrono;
import be.ac.vub.ir.util.UserPreferences;

public class FileReading {

	public static void main(String[] args) throws MalformedURLException {
		testLatencyHidingForJob(4);
		testLatencyHidingForFileFromURL();
		testLatencyHidingForFileFromSystem();

	}
	//======================== LATENCY HIDING TESTS  ===========================//
	// run on 1 processor (set affinity of eclipse process in task manager)
	public static void testLatencyHidingForJob(final int NBR_JOBS){
		
		final long ITERATIONS = 30000000L;
		final Thread[] t = new Thread[NBR_JOBS];
		
		Chrono totalT = new Chrono();
		for(int j = 0;j<NBR_JOBS;j++){ // start all jobs
			final int J=j;
			t[j] = new Thread(){
				public void run(){
					seedCalculation(ITERATIONS);
				};
			};
			t[j].start();
		}
		// wait for all jobs to finish
		for(int j = 0;j<NBR_JOBS;j++){ 
			try {
				t[j].join();
			} catch (InterruptedException e) {}	
		}
		totalT.stop();
		
		// time of 1 job
		Chrono jobT = new Chrono();
		seedCalculation(ITERATIONS);
		jobT.stop();
		
		System.out.println("Total time = "+totalT+" (sum of job times = "+Chrono.toString(jobT.elapsedtime()*NBR_JOBS)+"); average job time = "+jobT);
		System.out.println(" => speedup = "+Fmath.truncate((float)jobT.elapsedtime()*NBR_JOBS/totalT.elapsedtime(), 3));
		System.out.println();
	}
	public static void testLatencyHidingForFileFromURL() throws MalformedURLException{
		final long NBR = 25000000; // set this number so that the time of the job is similar to that of the file reading
	
		Chrono seq = new Chrono();
		URL url = new URL("http://parallel.vub.ac.be/research/causalModels/causalLearningWithKde.jar");
		Chrono reading = new Chrono();
		int count = countLinesInURL(url) ;
		reading.stop();
		System.out.println("URL "+url+" contains "+count+" lines in "+reading);
		
		Chrono calc = new Chrono();
		int seed = seedCalculation(NBR) ;
		calc.stop();
		seq.stop();
		System.out.println("The "+NBR+"th number is "+seed+" in "+calc);
		System.out.println("Total time = "+Chrono.toString(reading.elapsedtime() + calc.elapsedtime()));
		
		// the same file, but a copy, otherwise the first one is taken from the cache!
		URL url2 = new URL("http://parallel.vub.ac.be/research/causalModels/causalLearningWithKde_copy.jar");
		
		Chrono par = new Chrono();
		Thread t = new Thread(){
			public void run(){
		
				// some calculations...
				int seed = seedCalculation(NBR) ;
				System.out.println("The "+NBR+"th number is "+seed);
			}};
		t.start();
			
		count = countLinesInURL(url2) ;
		System.out.println("URL "+url2+" contains "+count+" lines");

		try {
			t.join();
		} catch (InterruptedException e) {	}
		
		par.stop();
		System.out.println("Seq "+seq+", par "+par);
		System.out.println("Parallel runtime "+par);
		System.out.println(" => speedup = "+Fmath.truncate((float)seq.elapsedtime()/par.elapsedtime(), 3) );
		System.out.println();
	}
	public static void testLatencyHidingForFileFromSystem() throws MalformedURLException{
		final long NBR = 25000000; // set this number so that the time of the job is similar to that of the file reading
	
		File file = openFile();
		Chrono seq = new Chrono();
		
		Chrono reading = new Chrono();
		int count = countLinesInFile(file);
		reading.stop();
		System.out.println("File "+file+" contains "+count+" lines in "+reading);
		
		Chrono calc = new Chrono();
		int seed = seedCalculation(NBR) ;
		calc.stop();
		seq.stop();
		System.out.println("The "+NBR+"th number is "+seed+" in "+calc);
		System.out.println("Total time = "+Chrono.toString(reading.elapsedtime() + calc.elapsedtime()));

		Chrono par = new Chrono();
		Thread t = new Thread(){
			public void run(){
				// some calculations...
				int seed = seedCalculation(NBR) ;
				System.out.println("The "+NBR+"th number is "+seed);
			}};
		t.start();
		
		count = countLinesInFile(file);
		System.out.println("File "+file+" contains "+count+" lines");
		
		try {
			t.join();
		} catch (InterruptedException e) {	}
		
		par.stop();
		System.out.println("Seq "+seq+", par "+par);
		System.out.println("Parallel runtime "+par);
		System.out.println(" => speedup = "+Fmath.truncate((float)seq.elapsedtime()/par.elapsedtime(), 3) );
		System.out.println();
	}
	//======================== FILE AND URL OPERATIONS  ===========================//
	public static int countLinesInFile(File file){
		BufferedReader reader = null;
		try{
			reader = new BufferedReader(new FileReader(file));
			
		} catch (FileNotFoundException e) {
			System.err.println("File "+file+" not found. Aborting...");
			return -1;
		}
		int count = 0;
		try {
			String line = reader.readLine();
			while (line != null){
				count++;
				line = reader.readLine();
			}
		} catch (IOException e) {
			System.err.println("Error reading line "+count+" of file "+file+". Aborting...");
		}
		return count;
	}
	public static int countLinesInURL(URL url){
		BufferedReader reader = null;
		try{
			URLConnection urlConn =  url.openConnection();
			InputStream inputStream =  urlConn.getInputStream();
			reader = new BufferedReader(new InputStreamReader(inputStream));
			
		} catch (IOException e) {
			System.err.println("URL "+url+" not found. Aborting...");
			return -1;
		}
		int count = 0;
		try {
			String line = reader.readLine();
			while (line != null){
				count++;
				line = reader.readLine();
			}
		} catch (IOException e) {
			System.err.println("Error reading line "+count+" of URL "+url+". Aborting...");
		}
		return count;
	}
	public static int seedCalculation(long nbr){
		int seed = (int)(Math.random()*1013);
		for(long i=0;i<nbr;i++)
			seed = (seed * 351 + 138) % 1013;
		return seed;
	}
	
	public static File openFile(){
		JFileChooser chooser = new JFileChooser();
		try{ 									// opens the last used folder
			String sessionSaveLocation = UserPreferences.getFileSaveLocation();
			chooser.setCurrentDirectory(new File(sessionSaveLocation));
		} catch(Exception e){};
		chooser.resetChoosableFileFilters();
		chooser.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
		chooser.showDialog(null, "Choose file");
		File file = chooser.getSelectedFile();
		try{
			UserPreferences.saveFileSaveLocation(file.getParent());
		} catch(Exception e){};
		return file;
	}
}