/*
    * 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.myfaces.tobago.internal.context;
  
  import org.apache.myfaces.tobago.internal.util.RandomUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.faces.component.UIViewRoot;
  import javax.faces.context.FacesContext;
  import java.io.Serializable;
  import java.lang.invoke.MethodHandles;
  
  public class Nonce implements Serializable {
  
    private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
    private static final String KEY = Nonce.class.getName();
  
    private Nonce() {
    }
  
    public static String getNonce(final FacesContext facesContext) {
      final UIViewRoot viewRoot = facesContext.getViewRoot();
      String nonce = (String) viewRoot.getViewMap().get(KEY);
      if (nonce == null) {
        nonce = RandomUtils.nextString();
        LOG.debug("Creating nonce='{}'", nonce);
        viewRoot.getViewMap().put(KEY, nonce);
      }
      return nonce;
    }
  }