/**

  * 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.creadur.whisker.model;

 import java.util.Collection;

 import java.util.Map;

 /**

  * Indicates that generating an instance of a license

  * from the template (for the license family) has failed.

  */

 public class LicenseTemplateException extends Exception {

     /** Exception are serializable, so provide a SUID. */

     private static final long serialVersionUID = -4085365930968672572L;

     /** Names the erroneous license */

     private final String licenseName;

     /**

      * Builds an exception indicating that parameter passed

      * do not fulfill expectations.

      * @param expectedParameters not null

      * @param actualParameters not null

      * @param licenseName not null

      * @return not null

      */

     public static LicenseTemplateException parameterMismatch(

             final Collection<String> expectedParameters,

             final Collection<String> actualParameters,

             final String licenseName) {

         final StringBuilder message = new StringBuilder("Parameter mismatch for license '");

         message.append(licenseName);

         message.append('.');

         explainDiffs(expectedParameters, actualParameters, message, " Missing parameters: ");

         explainDiffs(actualParameters, expectedParameters, message, " Unexpected parameters: ");

         return new LicenseTemplateException(message.toString(), licenseName);

     }

     /**

      * Explains the differences between the sample and the base.

      * @param sample not null

      * @param base not null

      * @param message not null

      * @param preamble not null

      */

     private static void explainDiffs(final Collection<String> sample,

             final Collection<String> base, final StringBuilder message,

             final String preamble) {

         boolean first = true;

         for (final String expected:sample) {

             if (!base.contains(expected)) {

                 if (first) {

                     first = false;

                     message.append(preamble);

                 } else {

                     message.append(", ");

                 }

                 message.append(expected);

             }

         }

         if (!first) {

             message.append('.');

         }

     }

     /**

      * Builds an instance.

      * @param parameters not null

      * @param licenseName not null

      * @return not null 

      */

     public static LicenseTemplateException notLicenseTemplate(

             final Map<String, String> parameters, final String licenseName) {

         final StringBuilder message = new StringBuilder("'");

         message.append(licenseName);

         message.append("' is not a templated license but parameters were set (");

         boolean first = true;

         for (final String name:parameters.keySet()) {

             if (first) {

                 first = false;

             } else {

                 message.append(", ");

             }

             message.append(name);

         }

         message.append(")");

         return new LicenseTemplateException(message.toString(), licenseName);

     }

     /**

      * Constructs an instance.

      * @param message not null

      * @param parameters parameters passed

      * @param licenseName license name, not null

      */

     private LicenseTemplateException(final String message, final String licenseName) {

         super(message);

         this.licenseName = licenseName;

     }

     /**

      * Gets the name of the erroneous license.

      * @return license name, not null

      */

     public String getLicenseName() {

         return licenseName;

     }

 }