package dk.thoerup.traininfoservice.banedk;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;



public class TimeoutMap<K,V> implements Map<K,V>{

	class CacheItem<T> {
		
		public CacheItem(T v) {
			value = v;
			lastupdate = System.currentTimeMillis();
		}
		
		public long lastupdate;
		public T value;
	}
	
	private ConcurrentHashMap<K,CacheItem<V>> cache = new ConcurrentHashMap<K,CacheItem<V>>();
	private long timeout;
	
	public TimeoutMap(int timeout) {
		this.timeout = timeout; 
	}


	@Override
	public void clear() {
		cache.clear();
		
	}

	@Override
	public boolean containsKey(Object key) {
		return cache.containsKey(key);
	}

	@Override
	public boolean containsValue(Object arg0) {
		//return values().contains(arg0);
		throw new UnsupportedOperationException();
	}

	@Override
	public Set<java.util.Map.Entry<K, V>> entrySet() {
		//TODO someday implement this
		throw new UnsupportedOperationException();
	}

	@Override
	public boolean isEmpty() {
		return cache.isEmpty();
	}

	@Override
	public Set<K> keySet() {
		return cache.keySet();
	}

	@Override
	public void putAll(Map<? extends K, ? extends V> arg0) {
		for(K key : arg0.keySet()) {
			this.put(key, arg0.get(key) );
		}
	}

	@Override
	public V remove(Object arg0) {
		return cache.remove(arg0).value;
	}

	@Override
	public int size() {
		return cache.size();
	}

	@Override
	public Collection<V> values() {
		ArrayList<V> values = new ArrayList<V>();
		for (CacheItem<V> item : cache.values()) {
			values.add( item.value );
		}
		
		return values;

	}

	@Override
	public V get(Object key) {
		long now = System.currentTimeMillis();
		
		CacheItem<V> item = cache.get(key);
				
		
		if (item != null) {
			if ( (item.lastupdate+timeout) < now) { //item too old
				return null;
			} else {
				return item.value; //item still good
			}
		} else {
			return null; // no item found
		}
	}

	@Override
	public V put(K key, V value) {		
		CacheItem<V> item= new CacheItem<V>(value);
		
		item = cache.put(key, item);
		
		if (item != null)
			return item.value;
		else
			return null; 
	}
	
}