import java.util.Map;
import java.util.List;
import java.util.HashMap;
import java.util.ArrayList;
import java.util.Collections;

/**
 * @author Tomas Sedmik
 * @version 08 12 2009
 */
public class DiaryImpl implements Diary {

    private Map<String, List<Event>> diary = new HashMap<String, List<Event>>();

    /**
     * Adds new event to the diary.
     * @param Event event to added to the diary.
     * @throws IllegalArgumentException:
     *   <ul>
     *    <li>if the event has no time set (time is empty or null).
     *    <li>if the event is null
     *   </ul>
     */
    public void addEvent(Event event) throws IllegalArgumentException {
        
        if (event == null) {
            
            IllegalArgumentException exc = new IllegalArgumentException("argument is null");
            throw exc;
        }
        
        if (event.getTime() == null) {
            
            IllegalArgumentException exc = new IllegalArgumentException("argument has time null");
            throw exc;
        }
        
        if (event.getTime().isEmpty()) {
            
            IllegalArgumentException exc = new IllegalArgumentException("argument has invalid time value");
            throw exc;
        }
        
        if (!diary.containsKey(event.getTime())) {
            
            List<Event> eventList = new ArrayList<Event>();
                
            eventList.add(event);
            diary.put(event.getTime(), eventList);
        }
        else {
            
            List<Event> eventList = diary.get(event.getTime());
               
            eventList.add(event);
        }
    }
    
    /**
     * Returns all event with time sets to the date.
     * @param date present date
     * @return unmodifiable list with events those 
     * have time set to the date
     */
    public List<Event> getEvents(String date) {
        
        if ((date != null)
            && (!date.isEmpty())) {
        
           return Collections.unmodifiableList(diary.get(date));
        }
        
        return null;
    }
    
    /**
     * Returns all events in the diary.
     * @return list of all events
     */
    public List<Event> getAllEvents() {
        
        List<Event> allEvents = new ArrayList<Event>();
        
        for (String key : diary.keySet()) {
            
            allEvents.addAll(diary.get(key));
        }
        
        return allEvents;
    }
    
}