/*
    * 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.config;
  
  import org.apache.myfaces.tobago.exception.TobagoConfigurationException;
  
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  
  public class ContentSecurityPolicy {
  
    private Mode mode;
    private Map<String, String> directiveMap;
  
    private boolean unmodifiable = false;
  
    private void checkLocked() throws IllegalStateException {
      if (unmodifiable) {
        throw new TobagoConfigurationException("The configuration must not be changed after initialization!");
      }
    }
  
    /**
     * Lock the configuration, so it cannot be modified any more.
     */
    public void lock() {
      unmodifiable = true;
      directiveMap = Collections.unmodifiableMap(directiveMap);
    }
  
    public ContentSecurityPolicy(final String mode) {
      this.mode = Mode.parse(mode);
      this.directiveMap = new HashMap<>();
    }
  
    public void merge(final ContentSecurityPolicy other) {
      checkLocked();
      for (final Map.Entry<String, String> entry : other.directiveMap.entrySet()) {
        addDirective(entry.getKey(), entry.getValue());
      }
      mode = other.mode;
    }
  
    public void addDirective(final String name, final String text) {
      final String old = directiveMap.get(name);
      if (old != null) {
        directiveMap.put(name, old + ' ' + text);
      } else {
        directiveMap.put(name, text);
      }
    }
  
    public Map<String, String> getDirectiveMap() {
      return directiveMap;
    }
  
    public Mode getMode() {
      return mode;
    }
  
    @Override
    public String toString() {
      return "ContentSecurityPolicy{"
          + "mode=" + mode
          + ", directiveMap=" + directiveMap
          + '}';
    }
  
    public enum Mode {
      ON("on"),
      OFF("off"),
      REPORT_ONLY("report-only");
  
      private final String value;
  
      Mode(final String value) {
        this.value = value;
      }
  
      public String getValue() {
        return value;
     }
 
     public static Mode parse(final String string) {
       if (ON.value.equals(string)) {
         return ON;
       } else if (OFF.value.equals(string)) {
         return OFF;
       } else if (REPORT_ONLY.value.equals(string)) {
         return REPORT_ONLY;
       } else {
         throw new IllegalArgumentException("Found: " + string);
       }
     }
   }
 
 }