/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jena.permissions.model.impl;

import org.apache.jena.datatypes.RDFDatatype;
import org.apache.jena.graph.NodeFactory;
import org.apache.jena.permissions.impl.ItemHolder;
import org.apache.jena.permissions.impl.SecuredItemInvoker;
import org.apache.jena.permissions.model.SecuredLiteral;
import org.apache.jena.permissions.model.SecuredModel;
import org.apache.jena.permissions.model.SecuredResource;
import org.apache.jena.rdf.model.Literal;
import org.apache.jena.rdf.model.Model;
import org.apache.jena.rdf.model.RDFVisitor;
import org.apache.jena.rdf.model.ResourceRequiredException;
import org.apache.jena.shared.AuthenticationRequiredException;
import org.apache.jena.shared.ReadDeniedException;

/**
 * Implementation of SecuredLiteral to be used by a SecuredItemInvoker proxy.
 */
public class SecuredLiteralImpl extends SecuredRDFNodeImpl implements
		SecuredLiteral {
	/**
	 * Get an instance of SecuredLiteral
	 * 
	 * @param securedModel
	 *            the item providing the security context.
	 * @param literal
	 *            the literal to secure
	 * @return SecuredLiteral
	 */
	public static SecuredLiteral getInstance(final SecuredModel securedModel,
			final Literal literal) {
		if (securedModel == null) {
			throw new IllegalArgumentException(
					"Secured securedModel may not be null");
		}
		if (literal == null) {
			throw new IllegalArgumentException("literal may not be null");
		}

		// check that literal has a securedModel.
		Literal goodLiteral = literal;
		if (goodLiteral.getModel() == null) {
			goodLiteral = securedModel.createTypedLiteral(
					literal.getLexicalForm(), literal.getDatatype());
		}

		final ItemHolder<Literal, SecuredLiteral> holder = new ItemHolder<Literal, SecuredLiteral>(
				goodLiteral);
		final SecuredLiteralImpl checker = new SecuredLiteralImpl(securedModel,
				holder);
		// if we are going to create a duplicate proxy, just return this
		// one.
		if (goodLiteral instanceof SecuredLiteral) {
			if (checker.isEquivalent((SecuredLiteral) goodLiteral)) {
				return (SecuredLiteral) goodLiteral;
			}
		}
		return holder.setSecuredItem(new SecuredItemInvoker(literal.getClass(),
				checker));
	}

	// the item holder that contains this SecuredLiteral
	private final ItemHolder<? extends Literal, ? extends SecuredLiteral> holder;

	/**
	 * Constructor
	 * 
	 * @param securityEvaluator
	 *            The security evaluator to use.
	 * @param graphIRI
	 *            the graph IRI to validate against.
	 * @param holder
	 *            The item holder that will contain this SecuredLiteral.
	 */

	private SecuredLiteralImpl(final SecuredModel securedModel,
			final ItemHolder<? extends Literal, ? extends SecuredLiteral> holder) {
		super(securedModel, holder);
		this.holder = holder;
	}

	@Override
	public SecuredLiteral asLiteral() {
		return holder.getSecuredItem();
	}

	@Override
	public SecuredResource asResource() {
		if (canRead()) {
			throw new ResourceRequiredException(asNode());
		} else {
			throw new ResourceRequiredException(
					NodeFactory.createLiteral("Can not read"));
		}
	}

	@Override
	public boolean getBoolean() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getBoolean();
	}

	@Override
	public byte getByte() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getByte();
	}

	@Override
	public char getChar() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getChar();
	}

	/**
	 * Return the datatype of the literal. This will be null in the case of
	 * plain literals.
	 */
	@Override
	public RDFDatatype getDatatype() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getDatatype();
	}

	/**
	 * Return the uri of the datatype of the literal. This will be null in the
	 * case of plain literals.
	 */
	@Override
	public String getDatatypeURI() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getDatatypeURI();
	}

	@Override
	public double getDouble() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getDouble();
	}

	@Override
	public float getFloat() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getFloat();
	}

	@Override
	public int getInt() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getInt();
	}

	@Override
	public String getLanguage() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getLanguage();
	}

	/**
	 * Return the lexical form of the literal.
	 */
	@Override
	public String getLexicalForm() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getLexicalForm();
	}

	@Override
	public long getLong() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getLong();
	}

	@Override
	public short getShort() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getShort();
	}

	@Override
	public String getString() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getString();
	}

	/**
	 * Return the value of the literal. In the case of plain literals this will
	 * return the literal string. In the case of typed literals it will return a
	 * java object representing the value. In the case of typed literals
	 * representing a java primitive then the appropriate java wrapper class
	 * (Integer etc) will be returned.
	 */
	@Override
	public Object getValue() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().getValue();
	}

	@Override
	public Literal inModel(final Model m) throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return m.createTypedLiteral(holder.getBaseItem().getLexicalForm(),
				holder.getBaseItem().getDatatype());
	}

	@Override
	public boolean isWellFormedXML() throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().isWellFormedXML();
	}

	/**
	 * Test that two literals are semantically equivalent. In some cases this
	 * may be the sames as equals, in others equals is stricter. For example,
	 * two xsd:int literals with the same value but different language tag are
	 * semantically equivalent but distinguished by the java equality function
	 * in order to support round tripping.
	 */
	@Override
	public boolean sameValueAs(final Literal other) throws ReadDeniedException,
			AuthenticationRequiredException {
		checkRead();
		return holder.getBaseItem().sameValueAs(other);
	}

	@Override
	public Object visitWith(final RDFVisitor rv) {
		return rv.visitLiteral(this);
	}
}