package de.fhdw.wtf.common.ast;
   
   import java.util.Collection;
   import java.util.Collections;
   import java.util.Iterator;
   
   import de.fhdw.wtf.common.ast.visitor.GroupElementExceptionVisitor;
   import de.fhdw.wtf.common.ast.visitor.GroupElementReturnVisitor;
   import de.fhdw.wtf.common.ast.visitor.GroupElementVisitor;
  import de.fhdw.wtf.common.constants.parser.AstDescriptionConstants;
  import de.fhdw.wtf.common.token.Token;
  
  /**
   * This class represents a {@link Group} in an abstract syntax tree of the <code>WTF-Language</code>. A {@link Group} is
   * either contained by a {@link Model} or by another {@link Group} and can contain multiple {@link GroupElement}s by
   * itself.
   */
  public final class Group extends SyntaxObject implements GroupElement {
  	
  	/**
  	 * generated.
  	 */
  	private static final long serialVersionUID = 1603342875497690969L;
  	
  	/**
  	 * Constant for Line-Break.
  	 */
  	private static final String BREAK = " \n";
  	
  	/**
  	 * The Elements of the group.
  	 */
  	private final Collection<GroupElement> groupElements;
  	
  	/**
  	 * The name of the group.
  	 */
  	private final Name name;
  	
  	/**
  	 * Private-Constructor of {@link Group}.
  	 * 
  	 * @param name
  	 *            name
  	 * @param groups
  	 *            Elements of the group
  	 * @param firstToken
  	 *            firstToken
  	 * @param lastToken
  	 *            lastToken
  	 */
  	private Group(final Name name, final Collection<GroupElement> groups, final Token firstToken, final Token lastToken) {
  		super(firstToken, lastToken);
  		this.groupElements = groups;
  		this.name = name;
  	}
  	
  	/**
  	 * Creates a {@link Group}-Object.
  	 * 
  	 * @param name
  	 *            name
  	 * @param groups
  	 *            Elements of the group
  	 * @param firstToken
  	 *            firstToken
  	 * @param lastToken
  	 *            lastToken
  	 * @return The Group-Object.
  	 */
  	public static Group create(final Name name,
  			final Collection<GroupElement> groups,
  			final Token firstToken,
  			final Token lastToken) {
  		return new Group(name, groups, firstToken, lastToken);
  	}
  	
  	/**
  	 * Creates a {@link Group}-Object.
  	 * 
  	 * @param name
  	 *            name
  	 * @param groups
  	 *            Elements of the group
  	 * @param firstToken
  	 *            firstToken
  	 * @return The Group-Object.
  	 */
  	public static Group create(final Name name, final Collection<GroupElement> groups, final Token firstToken) {
  		return new Group(name, groups, firstToken, null);
  	}
  	
  	@Override
  	public boolean equals(final Object o) {
  		if (o instanceof Group) {
  			boolean result = true;
  			final Group other = (Group) o;
  			result =
  					result && this.getName().equals(other.getName())
 							&& this.getGroupElements().size() == other.getGroupElements().size();
 			if (result) {
 				final GroupElement[] thisArray =
 						this.getGroupElements().toArray(new GroupElement[this.getGroupElements().size()]);
 				final GroupElement[] otherArray =
 						other.getGroupElements().toArray(new GroupElement[other.getGroupElements().size()]);
 				for (int i = 0; i < this.getGroupElements().size(); i++) {
 					result = result && thisArray[i].equals(otherArray[i]);
 				}
 				return result;
 			}
 		}
 		return false;
 	}
 	
 	@Override
 	public int hashCode() {
 		int result = this.getName().hashCode();
 		for (final GroupElement element : this.getGroupElements()) {
 			result ^= element.hashCode();
 		}
 		return result;
 	}
 	
 	@Override
 	public String toString() {
 		final StringBuilder result = new StringBuilder();
 		result.append(this.getName().toString()).append(AstDescriptionConstants.COLON_TOKEN)
 				.append(AstDescriptionConstants.GROUP_TOKEN).append(AstDescriptionConstants.EQUAL_TOKEN)
 				.append(AstDescriptionConstants.SQUARE_BRACKET_OPEN).append(BREAK);
 		final Iterator<GroupElement> i = this.getGroupElements().iterator();
 		while (i.hasNext()) {
 			final GroupElement current = i.next();
 			result.append(current.toString()).append(BREAK);
 		}
 		result.append(AstDescriptionConstants.SQUARE_BRACKET_CLOSE).append(AstDescriptionConstants.SEMICOLON_TOKEN);
 		return result.toString();
 	}
 	
 	@Override
 	public void accept(final GroupElementVisitor visitor) {
 		visitor.handle(this);
 	}
 	
 	@Override
 	public <X extends Exception> void accept(final GroupElementExceptionVisitor<X> visitor) throws X {
 		visitor.handle(this);
 	}
 	
 	@Override
 	public <X> X accept(final GroupElementReturnVisitor<X> visitor) {
 		return visitor.handle(this);
 	}
 	
 	// ///// PROJECTIONS ///////////
 	
 	/**
 	 * Returns a collection of {@link GroupElement}. The collection can't be modified.
 	 * 
 	 * @return the groups
 	 */
 	public Collection<GroupElement> getGroupElements() {
 		return Collections.unmodifiableCollection(this.groupElements);
 	}
 	
 	@Override
 	public Name getName() {
 		return this.name;
 	}
 	
 }