/*
    * Copyright (c) 2016 ingenieux Labs
    *
    * Licensed 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 br.com.ingenieux.mojo.beanstalk.util;
  
  import com.google.common.base.Predicate;
  
  import com.amazonaws.regions.Region;
  import com.amazonaws.services.elasticbeanstalk.model.EnvironmentDescription;
  
  import org.apache.commons.lang.StringUtils;
  
  import java.util.Set;
  import java.util.TreeSet;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import static java.lang.String.format;
  
  public class EnvironmentHostnameUtil {
    public static final Pattern PATTERN_HOSTNAME =
        Pattern.compile("(?<cnamePrefix>[\\p{Alnum}\\-]{4,63})(?<regionName>.\\p{Alpha}{2}\\-\\p{Alpha}{4,9}\\-\\p{Digit})?\\Q.elasticbeanstalk.com\\E$");
  
    public static Predicate<EnvironmentDescription> getHostnamePredicate(Region region, String cnamePrefix) {
      final Set<String> hostnamesToMatch = new TreeSet<String>(String.CASE_INSENSITIVE_ORDER);
  
      hostnamesToMatch.add(format("%s.elasticbeanstalk.com", cnamePrefix).toLowerCase());
      hostnamesToMatch.add(format("%s.%s.elasticbeanstalk.com", cnamePrefix, region.getName()).toLowerCase());
  
      return new Predicate<EnvironmentDescription>() {
        @Override
        public boolean apply(EnvironmentDescription t) {
          return hostnamesToMatch.contains(t.getCNAME());
        }
  
        @Override
        public String toString() {
          return format("... with cname belonging to %s", StringUtils.join(hostnamesToMatch.iterator(), " or "));
        }
      };
    }
  
    public static String ensureSuffix(String cname, Region region) {
      if (PATTERN_HOSTNAME.matcher(cname).matches()) {
        return cname;
      } else {
        return format("%s.%s.elasticbeanstalk.com", cname, region.toString());
      }
    }
  
    public static String ensureSuffixStripped(String cnamePrefix) {
      final Matcher matcher = PATTERN_HOSTNAME.matcher(cnamePrefix);
  
      if (matcher.matches()) {
        return matcher.group("cnamePrefix");
      }
  
      return cnamePrefix;
    }
  }