package org.argeo.naming;
   
   import java.util.Dictionary;
   import java.util.Enumeration;
   
   import javax.naming.NamingEnumeration;
   import javax.naming.NamingException;
   import javax.naming.directory.Attribute;
   import javax.naming.directory.Attributes;
  import javax.naming.directory.BasicAttribute;
  
  public class AttributesDictionary extends Dictionary<String, Object> {
  	private final Attributes attributes;
  
  	/** The provided attributes is wrapped, not copied. */
  	public AttributesDictionary(Attributes attributes) {
  		if (attributes == null)
  			throw new IllegalArgumentException("Attributes cannot be null");
  		this.attributes = attributes;
  	}
  
  	@Override
  	public int size() {
  		return attributes.size();
  	}
  
  	@Override
  	public boolean isEmpty() {
  		return attributes.size() == 0;
  	}
  
  	@Override
  	public Enumeration<String> keys() {
  		NamingEnumeration<String> namingEnumeration = attributes.getIDs();
  		return new Enumeration<String>() {
  
  			@Override
  			public boolean hasMoreElements() {
  				return namingEnumeration.hasMoreElements();
  			}
  
  			@Override
  			public String nextElement() {
  				return namingEnumeration.nextElement();
  			}
  
  		};
  	}
  
  	@Override
  	public Enumeration<Object> elements() {
  		NamingEnumeration<String> namingEnumeration = attributes.getIDs();
  		return new Enumeration<Object>() {
  
  			@Override
  			public boolean hasMoreElements() {
  				return namingEnumeration.hasMoreElements();
  			}
  
  			@Override
  			public Object nextElement() {
  				String key = namingEnumeration.nextElement();
  				return get(key);
  			}
  
  		};
  	}
  
  	@Override
  	/** @returns a <code>String</code> or <code>String[]</code> */
  	public Object get(Object key) {
  		try {
  			if (key == null)
  				throw new IllegalArgumentException("Key cannot be null");
  			Attribute attr = attributes.get(key.toString());
  			if (attr == null)
  				return null;
  			if (attr.size() == 0)
  				throw new IllegalStateException("There must be at least one value");
  			else if (attr.size() == 1) {
  				return attr.get().toString();
  			} else {// multiple
  				String[] res = new String[attr.size()];
  				for (int i = 0; i < attr.size(); i++) {
  					Object value = attr.get();
  					if (value == null)
  						throw new RuntimeException("Values cannot be null");
  					res[i] = attr.get(i).toString();
  				}
  				return res;
  			}
  		} catch (NamingException e) {
  			throw new RuntimeException("Cannot get value for " + key, e);
  		}
  	}
  
  	@Override
  	public Object put(String key, Object value) {
  		if (key == null)
 			throw new IllegalArgumentException("Key cannot be null");
 		if (value == null)
 			throw new IllegalArgumentException("Value cannot be null");
 
 		Object oldValue = get(key);
 		Attribute attr = attributes.get(key);
 		if (attr == null) {
 			attr = new BasicAttribute(key);
 			attributes.put(attr);
 		}
 
 		if (value instanceof String[]) {
 			String[] values = (String[]) value;
 			// clean additional values
 			for (int i = values.length; i < attr.size(); i++)
 				attr.remove(i);
 			// set values
 			for (int i = 0; i < values.length; i++) {
 				attr.set(i, values[i]);
 			}
 		} else {
 			if (attr.size() > 1)
 				throw new IllegalArgumentException("Attribute " + key + " is multi-valued");
 			if (attr.size() == 1) {
 				try {
 					if (!attr.get(0).equals(value))
 						attr.set(0, value.toString());
 				} catch (NamingException e) {
 					throw new RuntimeException("Cannot check existing value", e);
 				}
 			} else {
 				attr.add(value.toString());
 			}
 		}
 		return oldValue;
 	}
 
 	@Override
 	public Object remove(Object key) {
 		if (key == null)
 			throw new IllegalArgumentException("Key cannot be null");
 		Object oldValue = get(key);
 		if (oldValue == null)
 			return null;
 		return attributes.remove(key.toString());
 	}
 
 	/**
 	 * Copy the <b>content</b> of an {@link Attributes} to the provided
 	 * {@link Dictionary}.
 	 */
 	public static void copy(Attributes attributes, Dictionary<String, Object> dictionary) {
 		AttributesDictionary ad = new AttributesDictionary(attributes);
 		Enumeration<String> keys = ad.keys();
 		while (keys.hasMoreElements()) {
 			String key = keys.nextElement();
 			dictionary.put(key, ad.get(key));
 		}
 	}
 
 	/**
 	 * Copy a {@link Dictionary} into an {@link Attributes}.
 	 */
 	public static void copy(Dictionary<String, Object> dictionary, Attributes attributes) {
 		AttributesDictionary ad = new AttributesDictionary(attributes);
 		Enumeration<String> keys = dictionary.keys();
 		while (keys.hasMoreElements()) {
 			String key = keys.nextElement();
 			ad.put(key, dictionary.get(key));
 		}
 	}
 }