/* mobile.java */
/*
A Mobile can be constructed from strings (cords), struts, and weights.

The simplest mobile is just a weight hanging on a cord. 
We build bigger mobiles by replacing the weight with a strut 
that has another mobile hanging on both its left end and its right end.

Design the data that represents mobiles.
  
-- Draw the mobile on the given Canvas.
  
-- Compute the height of the mobile.
-- Compute the total weight of the mobile
-- determine whether the mobile is balanced - i.e. every strut is balanced
   (ask for a physics hint, if you need it)
*/

import draw.*;
import geometry.*;
import colors.*;

/*
               +--------+                  
               | Mobile |<----------------+
               +--------+                 |
               +--------+                 |
                   |                      |
                  / \                     |
                  ---                     |
                   |                      |
         ---------------------            |
         |                   |            |
  +--------------+    +--------------+    |
  | Item         |    | Support      |    |
  +--------------+    +--------------+    |
  | Posn origin  |    | Posn origin  |    |
  | IColor color |    | int offset   |    |
  +--------------+    | int length   |    |
                      | Mobile left  |-+  |
                      | Mobile right |-+  |
                      +--------------+ |  |
                                       |  |
                                       +--+

*/

// to represent a mobile
interface Mobile {

  boolean draw(Canvas c);
}

// to represent an item hanging at the end of a mobile
class Item implements Mobile {
  Posn origin;
  IColor color;

  Item(Posn origin, IColor color) {
    this.origin = origin;
    this.color = color;
  }

  boolean draw(Canvas c){
    return c.drawDisk(this.origin, 20, this.color);
  }
}

// to represent a part of support structure for a mobile
class Support implements Mobile {
  Posn origin;
  int leftSide;
  int rightSide;
  Mobile left;
  Mobile right;

  Support(Posn origin, int leftSide, int rightSide, Mobile left, Mobile right) {
    this.origin = origin;
    this.leftSide = leftSide;
    this.rightSide = rightSide;
    this.left = left;
    this.right = right;
  }

  boolean draw(Canvas c){
    return 

    // draw the left support 
    c.drawLine(this.origin, 
               new Posn(this.origin.x - this.leftSide, this.origin.y),  
               new Black()) &&

    // draw the left string
    c.drawLine(new Posn(this.origin.x - this.leftSide, this.origin.y),
               new Posn(this.origin.x - this.leftSide, this.origin.y + 30), 
               new Yellow()) &&

    // draw the left submobile
    this.left.draw(c) &&

    // draw the right support 
    c.drawLine(this.origin, 
               new Posn(this.origin.x + this.rightSide, this.origin.y), 
               new Black()) &&

    // draw the right string
    c.drawLine(new Posn(this.origin.x + this.rightSide, this.origin.y),
               new Posn(this.origin.x + this.rightSide, this.origin.y + 30), 
               new Yellow()) &&

    // draw the right submobile
    this.right.draw(c);
  }
}


class Examples {
  Examples(){}

  Mobile i1 = new Item(new Posn(70, 120), new Blue());
  Mobile i2 = new Item(new Posn(120, 120), new Red());
  Mobile i3 = new Item(new Posn(180, 90), new Green());
  Mobile i4 = new Item(new Posn(20, 90), new Green());

  Mobile s1 = new Support(new Posn(90, 90), 20, 30, this.i1, this.i2);
  Mobile s2 = new Support(new Posn(140, 60), 50, 40, this.s1, this.i3);
  Mobile s3 = new Support(new Posn(100, 30), 80, 40, this.i4, this.s2);
  
  Canvas c = new Canvas(300, 200); 
  
  boolean makeDrawing = 
    this.c.show() && 
    this.s3.draw(this.c); 

}