import javax.swing.*;
import java.awt.*;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.util.*;

public class LCSComponent extends JComponent{
	private String s1 = "";
	private String s2 = "";
	private String out = "";
	final int FONTHEIGHT = 20;

	public void paintComponent(Graphics g) {
		Graphics2D g2 = (Graphics2D) g;
		out = LCS.calculateLCS(s1, s2);

					
		g2.setFont(new Font("Monospaced",Font.BOLD,FONTHEIGHT));
		double w = g2.getFontMetrics().charWidth('A'); //System.out.println("width: "+w);// width of one character
		double[] x1 = new double[s1.length()];
		double y1 = 25; // upper left points of the characters of the first string (x1,y1)
		double[] x2 = new double[s2.length()];
		double y2 = getHeight()-30; // upper left points of the characters of the second string (x2,y2)
		double gap = 5; // gap between adjacent characters 		
		
		ArrayList<Point2D.Double> p1 = new ArrayList<Point2D.Double>();
		ArrayList<Point2D.Double> p2 = new ArrayList<Point2D.Double>(); // points of the lines		
		
		Line2D.Double line;
		//ArrayList<Line2D.Double> lines = new ArrayList<Line2D.Double>(); // the array of lines
		
		x1[0] = 10;
		p1.add(new Point2D.Double(x1[0]+w/2, y1+5));
		x2[0] = 10;
		p2.add(new Point2D.Double(x2[0]+w/2, y2-FONTHEIGHT));
				
		int i = 0;
		
		//System.out.println("point"+p1.get(0)+p2.get(0) );
		//g2.drawString("A", (int)x1[0], (int)y1);
		//g2.drawString("A", (int)x1[0], (int)y2);
		//g2.draw(new Line2D.Double (p1.get(0), p2.get(0)));

		// save the x coordinate of the points of each character in an array
		
		// points of the first string
		for(i = 1; i < s1.length(); i++){	
			x1[i] = x1[i-1] + w + gap;
			p1.add(new Point2D.Double(x1[i], y1+5));
			//System.out.println(i+", "+p1.get(i));
		}
		
		// points of the second string
		for(i = 1; i < s2.length(); i++){
			x2[i] = x2[i-1] + w + gap;
			p2.add(new Point2D.Double(x2[i], y2-FONTHEIGHT));
		}
				
		// save the string elements to an array
		String[] tmp1 = new String[s1.length()];
		for(i = 0; i < s1.length(); i++)
			tmp1[i] = String.valueOf(s1.charAt(i));		
		
		String[] tmp2 = new String[s2.length()];
		for(i = 0; i < s2.length(); i++)
			tmp2[i] = String.valueOf(s2.charAt(i));		
		
		String[] tmpOut = new String[out.length()];
		for(i = 0; i < out.length(); i++)
			tmpOut[i] = String.valueOf(out.charAt(i));

		// compare the first string with the LCS and draw the string
		int count = 0;
		for(String s: tmpOut){
			int ctl = 0;
			for(i = count; i < tmp1.length; i++){
				if( 0 == ctl && s.equalsIgnoreCase(tmp1[i])){
					g2.setColor(Color.red);
					//System.out.print("red "+tmp1[i]+"; ");
					g2.drawString(tmp1[i], (int)x1[i], (int)y1);
					count = i + 1;
					ctl = 1;
				}
				else{
					g2.setColor(Color.black);
					g2.drawString(tmp1[i], (int)x1[i], (int)y1);
					//System.out.print("black "+tmp1[i]+"; ");
					//p1.remove(i);
				}			
				//g2.drawString(tmp1[i], (int)x1[i], (int)y1+5);
			}	//	System.out.print("\n");
		}

		// compare the second string with the LCS and draw the string

		count = 0;		
		for(String s: tmpOut){
			int ctl = 0;
			for(i = count; i < tmp2.length; i++){
				if( 0 == ctl && s.equalsIgnoreCase(tmp2[i])){								
					g2.setColor(Color.red);					
					g2.drawString(tmp2[i], (int)x2[i], (int)y2);
					count = i + 1;
					ctl = 1;
				}
				else{
					g2.setColor(Color.black);
					g2.drawString(tmp2[i], (int)x2[i], (int)y2);
				//	p2.remove(i);
					///System.out.print(i+", "+p2.get(i));
				}
				//System.out.println(tmp2[i]);
				//g2.drawString(tmp2[i], (int)x2[i], (int)y2);
			}					
		}

		// draw the lines
		for( i = 0; i < p1.size(); i++){
			//System.out.println("bla");
			//line = new Line2D.Double (p1.get(i), p2.get(i));
			//g2.setColor(Color.red);
			//g2.draw(line);
		}

	}
	
	public void changeStrings(String a, String b){
		s1 = a;
		s2 = b;
		//repaint();
	}
}