import java.util.*;

public class Worm extends Thread { 

    static final int maxwormlen=100;
    static final int max_didnt_moves = 4;
    static final int pause_sleep = 100;    //ms
    static final int coma_sleep  = 4000;    
    static java.util.Random rand;
    static {rand = new java.util.Random(System.currentTimeMillis());}

    //each worm:
    int length;
    int head;
    int color;
    int didnt_move = 0;
    boolean keepRunning=true;
    int[] x = new int[maxwormlen];
    int[] y = new int[maxwormlen];



	
    public Worm() {
	
	length = rand.nextInt(WormWorld.maxlength-WormWorld.minlength+1) + 
	         WormWorld.minlength;
	head = 0;                        //queue
	color = rand.nextInt(WormWorld.numcolors-1) + 1;  //assume black is BG
	x[0] = rand.nextInt(WormWorld.cols) + 1;
	y[0] = rand.nextInt(WormWorld.rows) + 1;
	for (int i=1; i<length; i++) {
	    switch (rand.nextInt(4)) {
	    case 0:        //left
		if (x[i-1] > 1)
		    x[i] = x[i-1] - 1;
		else
		    x[i] = x[i-1];
		y[i] = y[i-1];
		break;
	    case 1:        //up
		x[i] = x[i-1];
		if (y[i-1] > 1)
		    y[i] = y[i-1] - 1;
		else
		    y[i] = y[i-1];
		break;
	    case 2:        //right
		if (x[i-1] < WormWorld.cols)
		    x[i] = x[i-1] + 1;
		else
		    x[i] = x[i-1];
		y[i] = y[i-1];
		break;
	    case 3:        //down
		x[i] = x[i-1];
		if (y[i-1] < WormWorld.rows)
		    y[i] = y[i-1] + 1;
		else
		    y[i] = y[i-1];
		break;
	    }
	}
    }

    public void run() {
	while (keepRunning) {
	    display();
	    try {
		Thread.sleep(pause_sleep);
	    }
	    catch (InterruptedException e) {
		System.out.println("InterruptedException caught");
	    }   

	    move();
	}
	//System.out.println(this);
	try {
	    Thread.sleep(coma_sleep);
	}
	catch (InterruptedException e) {
	}   
	WormWorld.worm_remove(this);   //from the set, use finalizer to cleanup
	//WormWorld.wormsetsize();
	death();
    }

    void death() {
    //    protected void finalize() {
	Ansiscreen.colorback_black();
	for (int i=0; i<length; i++) {
	    Ansiscreen.gotoxy(y[(i+head)%maxwormlen],
			      x[(i+head)%maxwormlen]);
	    System.out.print(' ');
	}
    }



    void display() {
	switch (color) {
	    //    case 0: colorback_black();   //BG.  not the color of any worm
	    //break;
	case 1: Ansiscreen.colorback_red();
	    break;
	case 2:Ansiscreen.colorback_green();
	    break;
	case 3:Ansiscreen.colorback_yellow();
	    break;
	case 4:Ansiscreen.colorback_blue();
	    break;
	case 5:Ansiscreen.colorback_magenta();
	    break;
	case 6:Ansiscreen.colorback_cyan();
	    break;
	case 7:Ansiscreen.colorback_white();
	    break;
	}
	
	Ansiscreen.gotoxy(y[head],x[head]);
	//System.out.print("a");
	System.out.print("o");
	
	for (int i=1; i<length; i++) {
	    Ansiscreen.gotoxy(y[(i+head)%maxwormlen],
			      x[(i+head)%maxwormlen]);
	    //System.out.print((char)('a'+i));
	    System.out.print(' ');
	}
    }


    void move() {
	int i;
	final int max_tries=10;
	
	if (head == 0)      //queue
	    i = maxwormlen - 1;
	else
	    i = head - 1;
	
	int tries=0;
	boolean moved=false;
	while (tries<=max_tries && !moved) {
	    tries++;
	    switch (rand.nextInt(4)) {
	    case 0:        //left
		if (x[(i+1)%maxwormlen]>1 && 
		    !self_intercept(x[(i+1)%maxwormlen]-1,
				    y[(i+1)%maxwormlen])
		    &&
		    !WormWorld.worms_intercept(x[(i+1)%maxwormlen]-1,
					       y[(i+1)%maxwormlen])
		     //allow worm to get tied up in a "knot"
		     //|| tries==max_tries   
		     ) {
		    x[i] = x[(i+1)%maxwormlen] - 1;
		    y[i] = y[(i+1)%maxwormlen];
		    moved = true;
		}
		break;
	    case 1:        //up
		if (y[(i+1)%maxwormlen]>1 &&
		    !self_intercept(x[(i+1)%maxwormlen],
				    y[(i+1)%maxwormlen]-1)
		    &&
		    !WormWorld.worms_intercept(x[(i+1)%maxwormlen],
					       y[(i+1)%maxwormlen]-1)
		     //|| tries==max_tries
		     ) {
		    y[i] = y[(i+1)%maxwormlen] - 1;
		    x[i] = x[(i+1)%maxwormlen];
		    moved = true;
		}
		break;
	    case 2:        //right
		if (x[(i+1)%maxwormlen]<WormWorld.cols 
		    &&
		    !self_intercept(x[(i+1)%maxwormlen]+1,
				    y[(i+1)%maxwormlen])
		    &&
		    !WormWorld.worms_intercept(x[(i+1)%maxwormlen]+1,
					       y[(i+1)%maxwormlen])
		     //|| tries==max_tries
		     ) {
		    x[i] = x[(i+1)%maxwormlen] + 1;
		    y[i] = y[(i+1)%maxwormlen];
		    moved = true;
		}
		break;
	    case 3:        //down
		if (y[(i+1)%maxwormlen]<WormWorld.rows &&
		    !self_intercept(x[(i+1)%maxwormlen],
				    y[(i+1)%maxwormlen]+1)
		    &&
		    !WormWorld.worms_intercept(x[(i+1)%maxwormlen],
					       y[(i+1)%maxwormlen]+1)
		     //|| tries==max_tries
		     ) {
		    y[i] = y[(i+1)%maxwormlen] + 1;
		    x[i] = x[(i+1)%maxwormlen];
		    moved = true;
		}
		break;
	    }
	}

	//erase end piece, if succeeded in getting new head
	if (moved) {
	    Ansiscreen.gotoxy(y[(length+head-1)%maxwormlen],
			      x[(length+head-1)%maxwormlen]);
	    Ansiscreen.colorback_black();
	    System.out.print(" ");
	    
	    if (head == 0)
		head = maxwormlen - 1;
	    else
		head--;
	    didnt_move = 0;
	}
	else if (++didnt_move == max_didnt_moves)
	    keepRunning = false;

    }


    //check if new head will self-intercept
    boolean self_intercept(int xi, int yi) {
	for (int i=1; i<length; i++)
	    if (xi==x[(head+i)%maxwormlen] && 
		yi==y[(head+i)%maxwormlen])
		return true;
	return false;
    }

    //check if coord will intercept me
    boolean intercept(int xi, int yi) {
	for (int i=0; i<length; i++)
	    if (xi==x[(head+i)%maxwormlen] && 
		yi==y[(head+i)%maxwormlen])
		return true;
	return false;
    }
    

}