/*
    * Copyright 2009 the original author or authors.
    * 
    * 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 org.openehealth.ipf.commons.ihe.xds.core.validate;
  
  import static org.apache.commons.lang3.Validate.notNull;
  import static org.openehealth.ipf.commons.ihe.xds.core.validate.ValidationMessage.*;
  import static org.openehealth.ipf.commons.ihe.xds.core.validate.ValidatorAssertions.metaDataAssert;
  
  import java.util.regex.Pattern;
  
  /**
   * Validates time values.
   * @author Jens Riemschneider
   */
  public class TimeValidator implements ValueValidator {
      private static final String YEAR = "[0-9]{4}";
      private static final String MONTH = "(0[1-9]|1[012])";
      private static final String DAY = "(0[1-9]|[12][0-9]|3[01])";
      private static final String HOUR = "([01][0-9]|2[0123])";
      private static final String MIN_SEC = "[0-5][0-9]";
      private static final String REG_EX =
          YEAR + "(" + MONTH + "(" + DAY + "(" + HOUR + "(" + MIN_SEC + "(" + MIN_SEC + ")?)?)?)?)?";
  
      private static final Pattern TIME_PATTERN = Pattern.compile(REG_EX);
  
      private final int minLen;
  
      /**
       * Initializes a validator which will check that the timestamp has the right format
       * and the given minimal length (to check the precision).
       *
       * @param minLen minimal length of the timestamp; "-1" means no check.
       */
      public TimeValidator(int minLen) {
          this.minLen = minLen;
      }
  
      /**
       * Initializes a validator which will check that the timestamp has the right format
       * without minimal length constraint.
       */
      public TimeValidator() {
          this(-1);
      }
  
      @Override
      public void validate(String time) throws XDSMetaDataException {
          notNull(time, "time cannot be null");
          metaDataAssert(TIME_PATTERN.matcher(time).matches(), INVALID_TIME, time);
          metaDataAssert((minLen < 0) || (time.length() >= minLen), TIME_PRECISION_TOO_LOW, time);
      }
  }