/*
    * 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.commons.lang3.time;
  
  import java.util.Date;
  import java.util.Objects;
  import java.util.TimeZone;
  
  /**
   * Custom time zone that contains offset from GMT.
   *
   * @since 3.7
   */
  final class GmtTimeZone extends TimeZone {
  
      private static final int MILLISECONDS_PER_MINUTE = 60 * 1000;
      private static final int MINUTES_PER_HOUR = 60;
      private static final int HOURS_PER_DAY = 24;
  
      // Serializable!
      static final long serialVersionUID = 1L;
  
      private static StringBuilder twoDigits(final StringBuilder sb, final int n) {
          return sb.append((char) ('0' + (n / 10))).append((char) ('0' + (n % 10)));
      }
      private final int offset;
  
      private final String zoneId;
  
      GmtTimeZone(final boolean negate, final int hours, final int minutes) {
          if (hours >= HOURS_PER_DAY) {
              throw new IllegalArgumentException(hours + " hours out of range");
          }
          if (minutes >= MINUTES_PER_HOUR) {
              throw new IllegalArgumentException(minutes + " minutes out of range");
          }
          final int milliseconds = (minutes + (hours * MINUTES_PER_HOUR)) * MILLISECONDS_PER_MINUTE;
          offset = negate ? -milliseconds : milliseconds;
          // @formatter:off
          zoneId = twoDigits(twoDigits(new StringBuilder(9)
              .append(TimeZones.GMT_ID)
              .append(negate ? '-' : '+'), hours)
              .append(':'), minutes)
              .toString();
          // @formatter:on
      }
  
      @Override
      public boolean equals(final Object obj) {
          if (this == obj) {
              return true;
          }
          if (!(obj instanceof GmtTimeZone)) {
              return false;
          }
          final GmtTimeZone other = (GmtTimeZone) obj;
          return offset == other.offset && Objects.equals(zoneId, other.zoneId);
      }
  
      @Override
      public String getID() {
          return zoneId;
      }
  
      @Override
      public int getOffset(final int era, final int year, final int month, final int day, final int dayOfWeek, final int milliseconds) {
          return offset;
      }
  
      @Override
      public int getRawOffset() {
          return offset;
      }
  
      @Override
      public int hashCode() {
          return Objects.hash(offset, zoneId);
      }
  
      @Override
      public boolean inDaylightTime(final Date date) {
          return false;
      }
  
      @Override
     public void setRawOffset(final int offsetMillis) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public String toString() {
         return "[GmtTimeZone id=\"" + zoneId + "\",offset=" + offset + ']';
     }
 
     @Override
     public boolean useDaylightTime() {
         return false;
     }
 }