import java.awt.Color;
import java.awt.Dimension;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Calendar;
import java.util.Scanner;

import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

import org.math.plot.Plot2DPanel;

public class Energy
{
    public static void main(String[] args) throws FileNotFoundException
    {
	// choose file
	JFileChooser chooser = new JFileChooser();
	int result;
	do
	{
	    result = chooser.showOpenDialog(null);
	}
	while (result != JFileChooser.APPROVE_OPTION);
	File file = chooser.getSelectedFile();

	// choose number of weeks
	Integer[] choices = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
	Integer choice;
	do
	{
	    choice= (Integer) JOptionPane.showInputDialog(null, "Pick the number of weeks", "Time frame", JOptionPane.QUESTION_MESSAGE, null, choices, 0);
	}
	while (choice == null);
	int week = choice.intValue();
	
	// compute the start date
	Calendar calendar = Calendar.getInstance();
	calendar.add(Calendar.WEEK_OF_YEAR, -week);
	String date = String.format("%1$te-%1$tb-%1$ty", calendar.getTime());
	
	// find line that start with the start date
	Scanner energy = new Scanner(file);
	String line;
	do
	{
	    line = energy.nextLine();
	}
	while (!line.startsWith(date));
	
	// for remaining lines, collect third value
	final int AMOUNT = 3;
	StringBuffer values = new StringBuffer();
	String[] part = line.split(",");
	values.append(part[AMOUNT]);
	while (energy.hasNextLine())
	{
	    line = energy.nextLine();
	    part = line.split(",");
	    values.append("," + part[AMOUNT]);
	}
	    
	// we are done with the Scanner
	energy.close();
	
	// store the third values in an array
	part = values.toString().split(",");
	double[] amount = new double[part.length];
	for (int i = 0; i < amount.length; i++)
	{
	    amount[i] = Double.parseDouble(part[i]);
	}
	
	// plot the graph
	Plot2DPanel plot = new Plot2DPanel();
	plot.addLinePlot("energy use", Color.BLUE, amount);
	plot.setAxisLabels("Hours", "MW");
	JFrame frame = new JFrame("Ontario energy use");
	final int HEIGHT = 500;
	final int WIDTH = 500;
	frame.setSize(new Dimension(HEIGHT, WIDTH));
	frame.setContentPane(plot);
	frame.setVisible(true); 
    }
}