import java.util.SortedSet;
import java.io.OutputStream;
import java.io.File;
import java.util.TreeSet;
import java.io.OutputStreamWriter;
import java.io.IOException;
import java.io.FileWriter;

/**
 * @author Tomas Sedmik, xsedmik@fi.muni.cz
 * @version 06 01 2010
 */
public class BarImpl implements Bar {

    private SortedSet<Drink> drinks = new TreeSet<Drink>();
    
    /**
     * Adds a new drink. 
     * 
     * @param drink Drink to add, must not be null
     * @return false if the drink is already present at the bar, true otherwise
     * @throws NullPointerException if drink param. is null
     */
    public boolean addDrink(Drink drink) {
       return drinks.add(drink); 
    }

    /**
     * @return all drinks at the bar sorted by the NATURAL ORDERING of drinks
     */
    public SortedSet<Drink> getDrinks() {
        return drinks;
    }

    /**
     * @return drinks SORTED BY THEIR PRICE, i.e. by the PriceComparator
     */
    public SortedSet<Drink> getPriceList() {
        SortedSet<Drink> tmp = new TreeSet<Drink>(new PriceComparator());
        tmp.addAll(drinks);
        return tmp;
    }
    
    /**
     * Writes names of drinks to given output stream. Drinks are writen
     * in the order defined by the PriceComparator.
     * 
     * @param os Output stream to write drinks to
     * @throws BarException on any I/O failure
     */
    public void printPriceList(OutputStream os) throws BarException {
        
        OutputStreamWriter osw = new OutputStreamWriter(os);
        SortedSet<Drink> tmp = getPriceList();

        try {
            for (Drink drink : tmp) {
                osw.write(drink.getName() + '\n');
            }
            osw.flush();
        }
        catch (IOException e) {
            throw new BarException("Output error",e);
        }
    }

    /**
     * Writes names of drinks to given file. Drinks are writen
     * in the order defined by the PriceComparator.
     * 
     * @param file File to write drinks to
     * @throws BarException on any I/O failure
     */
    public void printPriceList(File file) throws BarException {
        
        try {
            FileWriter fw = new FileWriter(file);
            SortedSet<Drink> tmp = getPriceList();
            
            for (Drink drink : tmp) {
                fw.write(drink.getName() + '\n');
            }
            
            fw.flush();
        }
        catch (IOException e) {
            throw new BarException("File output error",e);
        }
    }
}