//Create a Polygon class. A polygon is a closed shape with lines joining the corner points.
//You will keep the points in an array list. Use object of java.awt.Point for the point.

//Polygon will have as an instance variable an ArrayList of Points to hold the points
//The constructor takes no parameters but initializes the instance variable
//
//The add method adds a Point to the polygon
//
//The perimeter method returns the perimeter of the polygon
//
//The draw method draws the polygon by connecting consecutive points and then
//connecting the last point to the first.
//
//No methods headers or javadoc is provided this time. You get to try your hand at writing a class almost from scratch
//
// Need help starting this question? In the lesson titled
// "Starting points: Problem Set Questions", go to the
// problem titled "Problem Set 6 - Question 3" for some tips on
// how to begin.
//

import java.util.ArrayList;
import java.awt.Point;
public class Polygon
{
    // TODO: provide the required constructor, instance variable, and methods

    ArrayList<Point> points; // instance variable

    /**
    * Constructor for objects of class ArrayPointsMethods
    */
    public void ArrayPointsMethods(ArrayList<Point> arrayList)
    {
        // initialize instance variables
        points = arrayList;
    }


    /**
    * Add a point to the polygon.
    */
    public void add(Point point)
    {
        points.add(point); // Point newPoint = new Point(x, y); and then points.add(newPoint)
    }

    /**
    * return perimeter of polygon
    */

    public int perimeter()
    {

        int perimeter = 0;
        int x1 = 0;
        int y1 = 0;
        int x2 = 0;
        int y2 = 0;

        for (int i = 0; i <= points.size() ; i++)
        {
           if (i == 0)
           {
               x1 = points.get(i).x;
               y1 = points.get(i).y;
           }


           else if (i == points.size())
           {
               x2 = points.get(0).x;
               y2 = points.get(0).y;
               int distance = (int)Math.sqrt(Math.pow(x2-x1,2) + Math.pow(y2-y1,2));
               perimeter = perimeter + distance;
           }

           else
           {
               x2 = points.get(i).x;
               y2 = points.get(i).y;

               int distance = (int)Math.sqrt(Math.pow(x2-x1,2) + Math.pow(y2-y1,2));
               perimeter = perimeter + distance;

               x1 = x2;
               y1 = y2;
           }
        }

        return perimeter;
    }

    public void draw()
    {
        int x1 = 0;
        int y1 = 0;
        int x2 = 0;
        int y2 = 0;

        for (int i = 0; i <= points.size() ; i++)
        {
           if (i == 0)
           {
               x1 = points.get(i).x;
               y1 = points.get(i).y;
           }


           else if (i == points.size())
           {
               x2 = points.get(0).x;
               y2 = points.get(0).y;
               Line line = new Line(x1, y1, x2, y2);
               line.draw();
           }

           else
           {
               x2 = points.get(i).x;
               y2 = points.get(i).y;

               Line line = new Line(x1, y1, x2, y2);
               line.draw();

               x1 = x2;
               y1 = y2;
           }
        }

    }
}