/**
 * Data class for a flock of birds
 * @author Thomas Bak
**/

import java.util.Vector;
import java.awt.*;

class Flock
{
    Vector vBirds;

    Flock()
    {
        vBirds = new Vector(5, 5);
        Bird bTemp;
        Color cTemp;

        // Create 40 new birds (35 bl, 5 r), random positions
        for (int iIndex = 0; iIndex < 40; iIndex++) {

            //if ( Math.random() * 50 < 45 )
            if (iIndex < 35)
                cTemp = Color.blue;
            else
                cTemp = Color.red;

            bTemp = new Bird(   (int) (Math.random() * 300),
                                (int) (Math.random() * 300),
                                (int) (Math.random() * 24) * 15,
                                cTemp );

		    vBirds.addElement(bTemp);
        }

    }

    /**
     * Place a new bird into the flock
     * @param bird The bird to add
    **/
    void addBird( Bird bird )
    {
        vBirds.addElement( bird );
    }

    /**
     * Remove a bird from the flock
     * @param col The feather colors of the bird that must go
    **/
    void removeBird( Color col )
    {
        Bird bTemp;

        // Find a bird of the right color
        for (int i = 0; i < vBirds.size(); i++) {
            bTemp = (Bird) vBirds.elementAt(i);

            if (bTemp.getFeathers() == col) {
                vBirds.removeElementAt(i);
                i = vBirds.size();
            }
        }

    }

    /**
     * Move every bird in the flock
    **/
    public void move()
    {
		// Move each bird
		Bird bTemp;
		for (int i = 0; i < vBirds.size(); i++) {
			bTemp = (Bird) vBirds.elementAt(i);
			bTemp.move( generalHeading(bTemp) );
		}

    }

    /**
     * Calculate the general average heading of
     * the birds surrounding this bird.
     * @param b The bird in question
     * @return The average theta
    **/
    private int generalHeading(Bird b)
    {
        Point pSplotch = new Point(0,0); // The amalgamation of the birds' headings
        int iNumBirds=0;  // The number of birds that were included

        // Find all of the birds less than 50 distance away
        Bird bTemp;
		for (int i = 0; i < vBirds.size(); i++) {
			bTemp = (Bird) vBirds.elementAt(i);

			// If it's close enough, add it to the average aim position
			if ( b.getDistance(bTemp) < 50 ) {

			    // Follow same birds, run away from different ones
			    if ( b.getFeathers().equals(bTemp.getFeathers()) ) {
    	    	    pSplotch.x += bTemp.getAim().x;
	        	    pSplotch.y += bTemp.getAim().y;
	        	}
	        	else {
	        	    // Collision avoidance
	        	    if ( b.getAim().x < bTemp.getAim().x )
	        	        pSplotch.x = 0;
	        	    else
	        	        pSplotch.x = 1000;

	        	    if ( b.getAim().y < bTemp.getAim().y )
	        	        pSplotch.y = 0;
	        	    else
	        	        pSplotch.y = 1000;

	        	    iNumBirds = 0;
	        	    i = 1000;

             	}

			    iNumBirds++;

			    // Too close & !comparing to itself
			    if (b.getDistance(bTemp) < 10 && !b.equals(bTemp) ){//&& b.getFeathers().equals(bTemp.getFeathers()) ) {
			        // Tell this bird that it's too close to the others
			        b.isTooClose();
    		    }

			}
		}

        // Calc the average heading relative position
        pSplotch.x /= iNumBirds;
        pSplotch.y /= iNumBirds;

        // Calculate the goal theta
		double gah = ( (double)(b.getY() - pSplotch.y) / (double)(pSplotch.x - b.getX() ) );
		int iGoalTheta = (int) (Math.atan(gah) * (180 / Math.PI));

		// Fix Q2 & Q3 bug
		if (pSplotch.x < b.getX() ) iGoalTheta = 180 + iGoalTheta;
		// Fix Q4 negative theta bug
		if (iGoalTheta < 0) iGoalTheta = 360 + iGoalTheta;

        return (int)(iGoalTheta / 15) * 15;
    }

    /**
     * Display the entire flock
    **/
    public void display( Graphics g )
    {
        // Draw each bird
		Bird bTemp;
		for (int i = 0; i < vBirds.size(); i++) {
			bTemp = (Bird) vBirds.elementAt(i);
			bTemp.display(g);
		}

    }
}