import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.ArrayList;

/**
* class EulerPanel.  This class creates the JPanel that runs the EulersMethod.class, with text fields
* for entering functions of F, timestep h, starting point x0, and final time limit T.  There are also 
* buttons to zoom in and out of the graph created
*
* @author Allison Gooch - agooch3
*/

public class EulerPanel extends JPanel {

	// fields and buttons
	private JButton startButton, zoomIn, zoomOut;
	private JTextField function1, function2, h, x0, T;
	// arraylists for use by EulersMethod.class
	public static ArrayList<Double> xResults1, yResults1, xResults2, yResults2, xResults3, yResults3;
	// instantiates intervals for use by zoom buttons
	private double intervalX = 10, intervalY = 10;
	
	// EulerPanel constructor instantiates and adds all buttons and fields
	public EulerPanel(){
		setBackground(Color.white);
		setPreferredSize(new Dimension(600, 600));
		
		// creates buttons and fields
		startButton = new JButton("Click to do Euler's Method");
		zoomIn = new JButton("Zoom in");
		zoomOut = new JButton("Zoom out");
		function1 = new JTextField();
		function2 = new JTextField();
		h = new JTextField();
		x0 = new JTextField();
		T = new JTextField();
		
		// creates arraylists
		xResults1 = new ArrayList<Double>();
		yResults1 = new ArrayList<Double>();
		xResults2 = new ArrayList<Double>();
		yResults2 = new ArrayList<Double>();
		xResults3 = new ArrayList<Double>();
		yResults3 = new ArrayList<Double>();

		// adds panel of zoom buttons
		JPanel p4 = new JPanel();
		p4.setPreferredSize(new Dimension(600,30));
		p4.setBackground(Color.white);
		p4.add(zoomIn);
		p4.add(zoomOut);
		
		// adds panel of labels for fields
		JPanel p3 = new JPanel();
		p3.setPreferredSize(new Dimension(600,30));
		p3.setBackground(Color.white);
		JLabel l1 = new JLabel("Enter f");
		l1.setPreferredSize(new Dimension(150,30));
		JLabel l2 = new JLabel("Enter g");
		l2.setPreferredSize(new Dimension(150,30));
		JLabel l3 = new JLabel("Timestep h");
		l3.setPreferredSize(new Dimension(75,30));
		JLabel l4 = new JLabel("x0 as 'x,y'");
		l4.setPreferredSize(new Dimension(75,30));
		JLabel l5 = new JLabel("Final time T");
		l5.setPreferredSize(new Dimension(75,30));
		p3.add(l1);
		p3.add(l2);
		p3.add(l3);
		p3.add(l4);
		p3.add(l5);
		
		// adds panel of fields	
		JPanel p2 = new JPanel();
		p2.setPreferredSize(new Dimension(600,30));
		p2.setBackground(Color.white);
		function1.setPreferredSize(new Dimension(150,25));
		function2.setPreferredSize(new Dimension(150,25));
		h.setPreferredSize(new Dimension(75,25));
		x0.setPreferredSize(new Dimension(75,25));
		T.setPreferredSize(new Dimension(75,25));
		p2.add(function1);
		p2.add(function2);
		p2.add(h);	
		p2.add(x0);
		p2.add(T);
		
		// adds panel for start button	
		JPanel p = new JPanel();
		p.setPreferredSize(new Dimension(600,30));
		p.setBackground(Color.white);
		p.add(startButton);
		
		// adds panels to main panel
		add(p3);
		add(p2);
		add(p);
		add(p4);
		
		// adds button listener to all buttons
		ButtonListener b = new ButtonListener();
		startButton.addActionListener(b);
		function1.addActionListener(b);
		function2.addActionListener(b);
		h.addActionListener(b);
		x0.addActionListener(b);
		T.addActionListener(b);
		ZoomListener z = new ZoomListener();
		zoomIn.addActionListener(z);
		zoomOut.addActionListener(z);
		
	} // end JacobiPanel constructor


	public void paintComponent (Graphics page){
		super.paintComponent(page);
		
		// sets default page look
		Font font = new Font("Comic Sans", Font.BOLD, 12);
		page.setFont(font);
		page.setColor(Color.black);
		
		// draws key to the graph above graph
		page.drawString("Key: Red graph = h", 420, 155);
		page.drawString("Blue graph = h/10", 450, 170);
		page.drawString("Green graph = h/100", 450, 185);
			
		// draws graph axes and labels them
		page.drawLine(300, 190, 300, 590);
		page.drawLine(50, 390, 550, 390);
		page.drawString("X", 540, 405);
		page.drawString("Y", 305, 200);
			
		// creates reference variables for graphing
		int originX = 300;
		int originY = 390;
			
		// graphing algorithm uses interval and arraylist components to graph all graphs
		// red = h
		for (int i = 0; i < xResults1.size(); i++){
			try {
				page.setColor(Color.red);
				page.drawLine((int)(Math.round(originX + xResults1.get(i)*intervalX)), (int)(Math.round(originY + (-1)*yResults1.get(i)*intervalY)), (int)(Math.round(originX + xResults1.get(i+1)*intervalX)), (int)(Math.round(originY + (-1)*yResults1.get(i+1)*intervalY)));
			}
			catch (Exception e){};
		}
		// blue = h/10
		for (int i = 0; i < xResults2.size(); i++){
			try {
				page.setColor(Color.blue);
				page.drawLine((int)(Math.round(originX + xResults2.get(i)*intervalX)), (int)(Math.round(originY + (-1)*yResults2.get(i)*intervalY)), (int)(Math.round(originX + xResults2.get(i+1)*intervalX)), (int)(Math.round(originY + (-1)*yResults2.get(i+1)*intervalY)));
			}
			catch (Exception e){};
		}
		// green = h/100
		for (int i = 0; i < xResults3.size(); i++){
			try {
				page.setColor(Color.green);
				page.drawLine((int)(Math.round(originX + xResults3.get(i)*intervalX)), (int)(Math.round(originY + (-1)*yResults3.get(i)*intervalY)), (int)(Math.round(originX + xResults3.get(i+1)*intervalX)), (int)(Math.round(originY + (-1)*yResults3.get(i+1)*intervalY)));
			}
			catch (Exception e){};
		}

	} // end paintComponent
	
	
	private class ButtonListener implements ActionListener {
	
		String fInput, gInput, hInput, x0Input, TInput, xInput, yInput;
		double xVal, yVal;
		int commaLoc;
		
		public void actionPerformed (ActionEvent e){
		
			// gets input from text fields once start button is clicked
			if (e.getSource() == startButton){
				try {
					fInput = function1.getText();
					gInput = function2.getText();
					hInput = h.getText();
					x0Input = x0.getText();
					TInput = T.getText();

					// parses x0 input into a double for x and y components
					try {
						commaLoc = x0Input.indexOf(",");
						xInput = x0Input.substring(0, commaLoc);
						yInput = x0Input.substring(commaLoc+1, x0Input.length());
						xVal = Double.parseDouble(xInput);
						yVal = Double.parseDouble(yInput);
					} catch(Exception b){
						x0.setText("Format error");
					}
	
					// calls EulersMethod with the given input data
					new EulersMethod(fInput, gInput, hInput, xVal, yVal, TInput);
					repaint();
				} catch(Exception c){
					new EulersMethod("0", "0", "0", 0, 0, "0");
					repaint();
				}
			}

		} // end actionPerformed
		
	} // end ButtonListener
	
	private class ZoomListener implements ActionListener {
			
		public void actionPerformed (ActionEvent e){
		
			// if zoomIn is clicked, make the interval 10 pixels larger then repaint
			if (e.getSource() == zoomIn){
					intervalX = intervalX + 10;
					intervalY = intervalY + 10;
				repaint();
			}
			// if zoomOut is clicked, make the interval 10 pixels smaller then repaint
			// doesn't go smaller than 10 pixels
			if (e.getSource() == zoomOut){
				if (intervalX == 10 && intervalY ==10){
					intervalX = 10;
					intervalY = 10;
				}
				else {
					intervalX = intervalX - 10;
					intervalY = intervalY - 10;
				}
				repaint();
			}

		} // end actionPerformed
		
	} // end ZoomListener

} // end EulerPanel