import objectdraw.*;
import java.awt.*;
import javax.swing.*;

/**
 * A general collection class to store Drawable Shapes.
 */
public class ShapeCollection {

    private static final int MAX_OBJECTS = 20;
    
    // Array of objects in collection
    private DrawableInterface[] shapes;

    // number of objects in collection
    private int numShapes;

    /*
     * Create a new, empty Collection
     */
    public ShapeCollection() {
         shapes = new DrawableInterface[MAX_OBJECTS];
         numShapes = 0;
    }

    /*
     * Add the shape to the collection.
     */
    public void add(DrawableInterface shape) {
        // only add if still room for more objects
        if (numShapes < shapes.length) {
            shapes[numShapes] = shape;
            numShapes++;
        }
    }

    /*
     * Add the shape to the beginning of the collection.
     */
    public void addFirst(DrawableInterface shape) {
       if (numShapes < shapes.length) {
           for (int i = numShapes; i > 0; i--) {
              shapes[i] = shapes[i - 1];
           }
           shapes[0] = shape;
           numShapes++;
        }
    }

    /*
     * Return the first shaping containing point, starting from the most
     * recently added shape.
     */
    public DrawableInterface selectedShape(Location point) {
        // Walk the array until we find the selected shape
        for (int selectIndex = numShapes - 1; selectIndex >= 0; selectIndex--) {
            if (shapes[selectIndex].contains(point)) {
                return shapes[selectIndex];
            }
        }

        return null;
    }
    
    public void remove(DrawableInterface shape) {
        int selectIndex = getIndexOf(shape);

        // if point is in one of the objects, delete it
        if (selectIndex != -1) {
            for (int i = selectIndex; i < (numShapes - 1); i++) {
                shapes[i] = shapes[i + 1];
            }

            numShapes--;
            shapes[numShapes] = null;
        }
    }
    
    
    /*
     * Helper method to return the index of the given shape.
     */
    private int getIndexOf(DrawableInterface shape) {
        // Walk the array until we find the selected shape
        for (int selectIndex = numShapes - 1; selectIndex >= 0; selectIndex--) {
            if (shapes[selectIndex] == shape) {
                return selectIndex;
            }
        }

        return -1;
    }
}