/*
    * 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.maven.enforcer.rules.files;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.maven.enforcer.rule.api.EnforcerRuleError;
  import org.apache.maven.enforcer.rule.api.EnforcerRuleException;
  import org.apache.maven.enforcer.rules.AbstractStandardEnforcerRule;
  
  /**
   * Contains the common code to compare an array of files against a requirement.
   *
   * @author <a href="mailto:brianf@apache.org">Brian Fox</a>
   */
  abstract class AbstractRequireFiles extends AbstractStandardEnforcerRule {
  
      /** List of files to check. */
      private List<File> files = Collections.emptyList();
  
      /** if null file handles should be allowed. If they are allowed, it means treat it as a success. */
      private boolean allowNulls = false;
  
      /** Allow that a single one of the files can make the rule to pass. */
      private boolean satisfyAny;
  
      // check the file for the specific condition
      /**
       * Check one file.
       *
       * @param file the file
       * @return <code>true</code> if successful
       */
      abstract boolean checkFile(File file);
  
      // return standard error message
      /**
       * Gets the error msg.
       *
       * @return the error msg
       */
      abstract String getErrorMsg();
  
      @Override
      public void execute() throws EnforcerRuleException {
  
          if (!allowNulls && files.isEmpty()) {
              throw new EnforcerRuleError("The file list is empty and Null files are disabled.");
          }
  
          List<File> failures = new ArrayList<>();
          for (File file : files) {
              if (!allowNulls && file == null) {
                  failures.add(file);
              } else if (!checkFile(file)) {
                  failures.add(file);
              }
          }
  
          if (satisfyAny) {
              int passed = files.size() - failures.size();
              if (passed == 0) {
                  fail(failures);
              }
          }
          // if anything was found, log it with the optional message.
          else if (!failures.isEmpty()) {
              fail(failures);
          }
      }
  
      private void fail(List<File> failures) throws EnforcerRuleException {
          String message = getMessage();
  
          StringBuilder buf = new StringBuilder();
          if (message != null) {
              buf.append(message + System.lineSeparator());
          }
          buf.append(getErrorMsg());
  
         for (File file : failures) {
             if (file != null) {
                 buf.append(file.getAbsolutePath() + System.lineSeparator());
             } else {
                 buf.append("(an empty filename was given and allowNulls is false)" + System.lineSeparator());
             }
         }
 
         throw new EnforcerRuleException(buf.toString());
     }
 
     @Override
     public String getCacheId() {
         return Integer.toString(files.hashCode());
     }
 
     void setFilesList(List<File> files) {
         this.files = files;
     }
 
     // method using for testing purpose ...
 
     List<File> getFiles() {
         return files;
     }
 
     void setAllowNulls(boolean allowNulls) {
         this.allowNulls = allowNulls;
     }
 
     void setSatisfyAny(boolean satisfyAny) {
         this.satisfyAny = satisfyAny;
     }
 
     @Override
     public String toString() {
         return String.format(
                 "%s[message=%s, files=%s, allowNulls=%b, satisfyAny=%b]",
                 getClass().getSimpleName(), getMessage(), files, allowNulls, satisfyAny);
     }
 }