// D. Scott
// CCI - Problem 3.6
// Animal shelter queuing system using LinkedList

import java.util.LinkedList;

class Animal {
    String type;
    int id;
    
    public Animal(String t, int id) {
        type = t;
        this.id = id;
    }
}

class AdoptionQueue {
    LinkedList<Animal> all;
    LinkedList<Animal> dogs;
    LinkedList<Animal> cats;
    
    public AdoptionQueue() {
        all = new LinkedList<Animal>();
        dogs = new LinkedList<Animal>()
        cats = new LinkedList<Animal>()
    }
    
    void enqueue(Animal a) {
        all.addLast(a);
        if (a.type == "dog")
            dogs.addLast(a);
        if(a.type == "cat")
            cats.addLast(a);
        System.out.println("Added " + a.type + " " + 
                          a.id + " to the adoption queue.");
    }
    
    Animal dequeueAny() {
        if (all.peek() == null) {
            System.out.println("\tNo animals available for adoption.");
            return;
        }

        Animal a = all.removeFirst();
        dogs.remove(a);
        cats.remove(a);
        return a;
    }
    
    Animal dequeueDog() {
        if (dogs.peek() == null) {
            System.out.println("\tNo dogs available for adoption.");
            return;
        }
        Animal d = dogs.removeFirst();
        all.remove(d);
        return d;
    }
    
    Animal dequeueCat() {
        if (cats.peek() == null) {
            System.out.println("\tNo cats available for adoption.");
            return;
        }

        Animal c = cats.removeFirst();
        all.remove(c);
        return c;
    }
    
}
   

public static void main (String[] args)
{

    AdoptionQueue a_queue = new AdoptionQueue();
    Animal a1 = new Animal("dog",4);
    Animal a2 = new Animal("dog",32);
    Animal a3 = new Animal("cat",18);
    Animal a4 = new Animal("dog",26);
    Animal a5 = new Animal("cat",9);
    Animal a6 = new Animal("cat",21);
    Animal a7 = new Animal("dog",14);
    a_queue.enqueue(a1);
    a_queue.enqueue(a2);
    a_queue.enqueue(a3);
    a_queue.enqueue(a4);
    a_queue.enqueue(a5);
    a_queue.enqueue(a6);
    a_queue.enqueue(a7);
    
    System.out.println("\n Select cat:");
    Animal cat1 = a_queue.dequeueCat();
    System.out.println("\t" + cat1.type + " " 
                       + cat1.id + " selected for adoption.");
    System.out.println("\n Select any:");
    Animal any1 = a_queue.dequeueAny();
    System.out.println("\t" + any1.type + " " 
                       + any1.id + " selected for adoption.");
    System.out.println("\n Select any:");
    any1 = a_queue.dequeueAny();
    System.out.println("\t" + any1.type + " " 
                       + any1.id + " selected for adoption.");
    System.out.println("\n Select any:");
    any1 = a_queue.dequeueAny();
    System.out.println("\t" + any1.type + " " 
                       + any1.id + " selected for adoption.");
    System.out.println("\n Select dog:");
    Animal dog1 = a_queue.dequeueDog();
    System.out.println("\t" + dog1.type + " " 
                       + dog1.id + " selected for adoption.");
    System.out.println("\n Select any:");
    any1 = a_queue.dequeueAny();
    System.out.println("\t" + any1.type + " " 
                       + any1.id + " selected for adoption.");
    System.out.println("\n Select any:");
    any1 = a_queue.dequeueAny();
    System.out.println("\t" + any1.type + " " 
                       + any1.id + " selected for adoption.");
    System.out.println("\n Select dog:");
    dog1 = a_queue.dequeueDog();
    System.out.println("\n Select cat:");
    cat1 = a_queue.dequeueCat();
    System.out.println("\n Select any:");
    any1 = a_queue.dequeueAny();
}