import objectdraw.*;
import java.awt.*;


// Class to recursively draw animated parsley

class ParsleyTree extends ActiveObject {
    
    private static final int PAUSETIME = 1000;
    
    private static final double MINSIZE = 20.0;
    
    // constants for determining where and what size are the recursive children
    private static final double PI = Math.PI;
    private static final double LEFTANGLE = PI/6;    // angle of left branch to the stem
    private static final double LEFTFRAC = 0.35;     // at what fraction of the stem it starts
    private static final double LEFTSIZE = 0.75;     // what fraction of the stem will the left branch size be?
    private static final double CENTERANGLE = PI/4;  // continue from end of stem at this angle to current
    private static final double CENTERFRAC = 0.55;   // what fraction of the stem the new center stem is
    private static final double RIGHTANGLE = -PI/5;  // angle of right branch to the stem
    private static final double RIGHTFRAC = 0.65;   // at what fraction of the stem it starts
    private static final double RIGHTSIZE = 0.45;     // what fraction of the stem will the left branch size be?        
    
    private Location startLocation;                     // starting coordinates of stem
    private AngLine stem;                                       // stem of parsley plant
    private ParsleyTree left, center, right;// Three branches of parsley
    private DrawingCanvas canvas;                       // canvas to draw on
    private double size;                                        // size of stem
    private double direction;                           // angle of stem with positive x-axis
    
    
    // Draw stem of parsley in anticipation of later growth
    ParsleyTree(Location startLocation, double size, double direction, DrawingCanvas canvas) {
        stem = new AngLine(startLocation,size,direction,canvas);        // Draw stem and color green
        stem.setColor(Color.green);
        
        this.canvas = canvas;                                                   // Save parameters for execute method
        this.direction = direction;
        this.size = size;
        this.startLocation = startLocation;
        start();
    }
    
    // After pause, start growing parsley from stem
    public void run() {
        
        Location destLocation = stem.getEnd();          // end of stem
        double x = startLocation.getX();                        // Location of startLocation
        double y = startLocation.getY();
        double dx = destLocation.getX()-x;                      // Location of end of stem
        double dy = destLocation.getY()-y;
        
        pause(PAUSETIME);
        
        if ( size > MINSIZE ) {         // Big enough to keep growing
            left = new ParsleyTree(new Location(x + LEFTFRAC*dx, y + LEFTFRAC*dy),
                                   size * LEFTSIZE, direction + LEFTANGLE, canvas);                     
            center = new ParsleyTree(destLocation,
                                     size * CENTERFRAC, direction + CENTERANGLE, canvas);
            right = new ParsleyTree(new Location(x + RIGHTFRAC*dx, y + RIGHTFRAC*dy),
                                    size * RIGHTSIZE, direction + RIGHTANGLE, canvas); 
        }
    }
    
    // param x,y amount to move parsley
    public void move( double x, double y) {
        
        stem.move(x,y);                                 // move stem
        
        if (center!=null) {                             // move rest of parsley if grown
            left.move(x,y);
            center.move(x,y);
            right.move(x,y);
        }
    }
}