cs151/hw3/src/model/PhotoAlbumModel.java

package model;

import strategy.SortingStrategy;
import iterator.AlbumIterator;
import iterator.PhotoIterator;
import java.util.*;

public class PhotoAlbumModel {
    private List<Photo> photos;
    private SortingStrategy<Photo> sortingStrategy;
    private final List<ModelChangeListener> listeners;
    private AlbumIterator iterator;

    public interface ModelChangeListener {
        void onModelChanged();
    }

    public PhotoAlbumModel() {
        photos = new ArrayList<>();
        listeners = new ArrayList<>();
        iterator = new PhotoIterator(photos);
    }

    public void addPhoto(Photo photo) {
        photos.add(photo);
        sortPhotos();
        iterator = new PhotoIterator(photos);
        notifyListeners();
    }

    public void deletePhoto(String name) {
        Photo currentPhoto = iterator.current();
        photos.removeIf(photo -> photo.name().equals(name));
        if (photos.isEmpty()) {
            iterator = new PhotoIterator(photos);
        } else if (currentPhoto != null && currentPhoto.name().equals(name)) {
            iterator = new PhotoIterator(photos);
        }
        notifyListeners();
    }

    public void setSortingStrategy(SortingStrategy<Photo> strategy) {
        this.sortingStrategy = strategy;
        sortPhotos();
        iterator = new PhotoIterator(photos);
        notifyListeners();
    }

    private void sortPhotos() {
        if (sortingStrategy != null) {
            photos = sortingStrategy.sort(photos);
            iterator = new PhotoIterator(photos);
        }
    }

    public void addListener(ModelChangeListener listener) {
        listeners.add(listener);
    }

    private void notifyListeners() {
        for (ModelChangeListener listener : listeners) {
            listener.onModelChanged();
        }
    }

    public List<Photo> getPhotos() {
        return Collections.unmodifiableList(photos);
    }

    public Photo getCurrentPhoto() {
        try {
            return iterator.current();
        } catch (NoSuchElementException e) {
            return null;
        }
    }

    public boolean hasNext() {
        return iterator.hasNext();
    }

    public boolean hasPrevious() {
        return iterator.hasPrevious();
    }

    public Photo next() {
        try {
            Photo next = iterator.next();
            notifyListeners();
            return next;
        } catch (NoSuchElementException e) {
            return null;
        }
    }

    public Photo previous() {
        try {
            Photo prev = iterator.previous();
            notifyListeners();
            return prev;
        } catch (NoSuchElementException e) {
            return null;
        }
    }
}