package fromLeonard;

import java.util.ArrayList;

/**
 * Creates a list of primes. Starts with 1, ends with a number specified in the
 * constructor.
 *
 * @author Pi-Nerd Fisher
 * @version 2.0
 */
public class Primes {
    // instance fields
    private ArrayList<Integer> foo = new ArrayList<Integer>();
    private ArrayList<Integer> primes = new ArrayList<Integer>();
    private int limit;
    private static int LOWEST_PRIME = 2;

    // constructor
    /**
     * Creates a list of primes from 2 to limit.
     *
     * @param limit
     *            The largest number to look for primes in.
     */
    public Primes(int limit) {
        this.limit = limit;
        fillList(LOWEST_PRIME);
        getPrimes();
    }

    // methods
    private void fillList(int start) {
        for (int i = start; i <= limit; i++) {
            this.foo.add(i);
        }
    }

    private void getPrimes() {
        while (!foo.isEmpty()) {
            if (primes.isEmpty()) {
                primes.add(foo.get(0));
                foo.remove(0);
            } else {
                if (checkPrime(foo.get(0), 0)) {
                    primes.add(foo.get(0));
                    foo.remove(0);
                } else {
                    foo.remove(0);
                }
            }
        }
    }

    private boolean checkPrime(int bar, int j) {
        while (j < primes.size()) {
            if (bar % primes.get(j) == 0) {
                return false;
            } else {
                j++;
            }
        }
        return true;
    }

    /**
     * Gets the list of all primes lower than the number in the constructor.
     *
     * @return an ArrayList with primes
     */
    public ArrayList<Integer> getList() {
        return primes;
    }
}