/**
 * An implementation of the BagOfPets Interface 
 * 
 * Note that everything marked with @Override does not need documentation as it
 * should be documented elsewhere.
 * @author gtowell
 * Created: July 2021
 * 
 */
public class PetBag implements BagOfPets {
    /** The array holding the information in the bag */
    private Pet[] petArray;

    /**
     * The default constructor.  
     * Creates a bag that can hold 100 pets.
     */
    public PetBag() {
        this(100);
    }
    /**
     * Constructor for pet bag
     * param sizeOfBag  is the size of the bag
    */
    public PetBag(int sizeOfBag) {
        petArray = new Pet[sizeOfBag];
    }

    @Override
    public int numberOfItems() {
        int count = 0;
        for (int i = 0; i < petArray.length; i++) {
            if (petArray[i] != null)
                count++;
        }
        return count;
    }

    @Override
    public boolean isEmpty() {
        return numberOfItems() == 0;
    }

    @Override
    public boolean add(Pet p) {
        int loc=0;
        while (loc < petArray.length && petArray[loc] != null) {
            loc++;
        }
        if (loc == petArray.length){
            return false;
        } else {
            petArray[loc] = p;
            return true;
        }
    }

    @Override
    public Pet remove() {
        int loc=0;
        while (loc < petArray.length && petArray[loc] == null) {
            loc++;
        }
        if (loc == petArray.length){
            return null;
        } else {
            Pet tmp = petArray[loc];
            petArray[loc] = null;
            return tmp;
        }
    }

    @Override
    public boolean remove(Pet p) {
        boolean found = false;
        for (int i = 0; i < petArray.length; i++) {
            if (petArray[i] == p) {
                found = true;
                petArray[i] = null;
            }
        }
        return found;
    }

    @Override
    public void clear() {
        for (int i = 0; i < petArray.length; i++) {
            petArray[i] = null;
        }
    }

    @Override
    public int countOf(Pet p) {
        int count = 0;
        for (int i = 0; i < petArray.length; i++) {
            if (petArray[i] == p) {
                count++;
            }
        }
        return count;
    }

    @Override
    public boolean contains(Pet p) {
        return countOf(p) > 0;
    }

    @Override
    public void display() {
        System.out.println(toString());
    }

    @Override
    public String toString() {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < petArray.length; i++) {
            if (petArray[i] != null) {
                sb.append(petArray[i].toString());
                sb.append("\n");
            }
        }
        return sb.toString();
    }
    
}