package ca.ubc.cs.cpsc210.moreiterators;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * A collection-like class that stores its data in two separate lists
 *
 * Iterating over the data could return the data in a number of different ways:
 *      1) all the data from listone followed by all the data from listtwo
 *      2) the data from listone and listtwo alternating (one from listone, then
 *         one from listtwo, then one from listone, ...). When one list runs out, then
 *         return the rest of the data from the other list until it too runs out
 *      3) the data from the two lists combined (cartesian product style) by multiplying.
 *         If there are three items in each list, named l11, l12, l13 and l21, l22, l23
 *         This would be l11 * l21, l11 * l22, l11 * l23,
 *                       l12 * l21, l12 * l22, l12 * l23,
 *                       l13 * l21, l13 * l22, l13 * l23,
 */
public class TwoLists implements Iterable<Integer>{
    private List<Integer> listone;
    private List<Integer> listtwo;

    public TwoLists() {
        listone = new ArrayList<Integer>();
        listtwo = new ArrayList<Integer>();
    }

    public void add(int which, Integer value) {
        switch (which) {
            case 1:
                listone.add(value);
                break;
            case 2:
                listtwo.add(value);
                break;
        }
    }

    @Override
    public Iterator<Integer> iterator(){
        return new twoListIterator();
    }

    private class twoListIterator implements Iterator<Integer>{
        int OIndex;
        int TIndex;
        boolean onFirst;

        public twoListIterator(){
            OIndex = 0;
            TIndex = 0;
            onFirst = true;
        }

        @Override
        public boolean hasNext(){
            if(OIndex < listone.size() && onFirst == true){
                return true;
            } else if( TIndex < listtwo.size() && onFirst == false){
                return true;
            } else
                return false;

        }

        @Override
        public Integer next(){
            if(onFirst){
                int next = OIndex;
                OIndex++;
                onFirst = false;
                return listone.get(next);
            } else {
                int next = TIndex;
                TIndex++;
                onFirst = true;
                return listtwo.get(next);
            }
        }

        @Override
        public void remove(){
            throw new UnsupportedOperationException();
        }


    }
}