/*
    * 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
    *
    *      https://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.validator.routines;
  
  import java.text.DateFormat;
  import java.text.Format;
  import java.util.Calendar;
  import java.util.Date;
  import java.util.Locale;
  import java.util.TimeZone;
  
  /**
   * <p><strong>Date Validation</strong> and Conversion routines ({@code java.util.Date}).</p>
   *
   * <p>This validator provides a number of methods for validating/converting
   *    a {@link String} date value to a {@code java.util.Date} using
   *    {@link DateFormat} to parse either:</p>
   *    <ul>
   *       <li>using the default format for the default {@link Locale}</li>
   *       <li>using a specified pattern with the default {@link Locale}</li>
   *       <li>using the default format for a specified {@link Locale}</li>
   *       <li>using a specified pattern with a specified {@link Locale}</li>
   *    </ul>
   *
   * <p>For each of the above mechanisms, conversion method (that is, the
   *    {@code validate} methods) implementations are provided which
   *    either use the default {@code TimeZone} or allow the
   *    {@code TimeZone} to be specified.</p>
   *
   * <p>Use one of the {@code isValid()} methods to just validate or
   *    one of the {@code validate()} methods to validate and receive a
   *    <em>converted</em> {@code Date} value.</p>
   *
   * <p>Implementations of the {@code validate()} method are provided
   *    to create {@code Date} objects for different <em>time zones</em>
   *    if the system default is not appropriate.</p>
   *
   * <p>Once a value has been successfully converted the following
   *    methods can be used to perform various date comparison checks:</p>
   *    <ul>
   *       <li>{@code compareDates()} compares the day, month and
   *           year of two dates, returning 0, -1 or +1 indicating
   *           whether the first date is equal, before or after the second.</li>
   *       <li>{@code compareWeeks()} compares the week and
   *           year of two dates, returning 0, -1 or +1 indicating
   *           whether the first week is equal, before or after the second.</li>
   *       <li>{@code compareMonths()} compares the month and
   *           year of two dates, returning 0, -1 or +1 indicating
   *           whether the first month is equal, before or after the second.</li>
   *       <li>{@code compareQuarters()} compares the quarter and
   *           year of two dates, returning 0, -1 or +1 indicating
   *           whether the first quarter is equal, before or after the second.</li>
   *       <li>{@code compareYears()} compares the
   *           year of two dates, returning 0, -1 or +1 indicating
   *           whether the first year is equal, before or after the second.</li>
   *    </ul>
   *
   * <p>So that the same mechanism used for parsing an <em>input</em> value
   *    for validation can be used to format <em>output</em>, corresponding
   *    {@code format()} methods are also provided. That is you can
   *    format either:</p>
   *    <ul>
   *       <li>using a specified pattern</li>
   *       <li>using the format for a specified {@link Locale}</li>
   *       <li>using the format for the <em>default</em> {@link Locale}</li>
   *    </ul>
   *
   * @since 1.3.0
   */
  public class DateValidator extends AbstractCalendarValidator {
  
      private static final long serialVersionUID = -3966328400469953190L;
  
      private static final DateValidator VALIDATOR = new DateValidator();
  
      /**
       * Gets the singleton instance of this validator.
       * @return A singleton instance of the DateValidator.
       */
      public static DateValidator getInstance() {
          return VALIDATOR;
      }
  
      /**
       * Constructs a <em>strict</em> instance with <em>short</em>
      * date style.
      */
     public DateValidator() {
         this(true, DateFormat.SHORT);
     }
 
     /**
      * Constructs an instance with the specified <em>strict</em>
      * and <em>date style</em> parameters.
      *
      * @param strict {@code true} if strict
      *        {@code Format} parsing should be used.
      * @param dateStyle the date style to use for Locale validation.
      */
     public DateValidator(final boolean strict, final int dateStyle) {
         super(strict, dateStyle, -1);
     }
 
     /**
      * <p>Compare Dates (day, month and year - not time).</p>
      *
      * @param value The {@link Calendar} value to check.
      * @param compare The {@link Calendar} to compare the value to.
      * @param timeZone The Time Zone used to compare the dates, system default if null.
      * @return Zero if the dates are equal, -1 if first
      * date is less than the seconds and +1 if the first
      * date is greater than.
      */
     public int compareDates(final Date value, final Date compare, final TimeZone timeZone) {
         final Calendar calendarValue = getCalendar(value, timeZone);
         final Calendar calendarCompare = getCalendar(compare, timeZone);
         return compare(calendarValue, calendarCompare, Calendar.DATE);
     }
 
     /**
      * <p>Compare Months (month and year).</p>
      *
      * @param value The {@code Date} value to check.
      * @param compare The {@code Date} to compare the value to.
      * @param timeZone The Time Zone used to compare the dates, system default if null.
      * @return Zero if the months are equal, -1 if first
      * parameter's month is less than the seconds and +1 if the first
      * parameter's month is greater than.
      */
     public int compareMonths(final Date value, final Date compare, final TimeZone timeZone) {
         final Calendar calendarValue = getCalendar(value, timeZone);
         final Calendar calendarCompare = getCalendar(compare, timeZone);
         return compare(calendarValue, calendarCompare, Calendar.MONTH);
     }
 
     /**
      * <p>Compare Quarters (quarter and year).</p>
      *
      * @param value The {@code Date} value to check.
      * @param compare The {@code Date} to compare the value to.
      * @param timeZone The Time Zone used to compare the dates, system default if null.
      * @return Zero if the months are equal, -1 if first
      * parameter's quarter is less than the seconds and +1 if the first
      * parameter's quarter is greater than.
      */
     public int compareQuarters(final Date value, final Date compare, final TimeZone timeZone) {
         return compareQuarters(value, compare, timeZone, 1);
     }
 
     /**
      * <p>Compare Quarters (quarter and year).</p>
      *
      * @param value The {@code Date} value to check.
      * @param compare The {@code Date} to compare the value to.
      * @param timeZone The Time Zone used to compare the dates, system default if null.
      * @param monthOfFirstQuarter The  month that the first quarter starts.
      * @return Zero if the quarters are equal, -1 if first
      * parameter's quarter is less than the seconds and +1 if the first
      * parameter's quarter is greater than.
      */
     public int compareQuarters(final Date value, final Date compare, final TimeZone timeZone, final int monthOfFirstQuarter) {
         final Calendar calendarValue = getCalendar(value, timeZone);
         final Calendar calendarCompare = getCalendar(compare, timeZone);
         return super.compareQuarters(calendarValue, calendarCompare, monthOfFirstQuarter);
     }
 
     /**
      * <p>Compare Weeks (week and year).</p>
      *
      * @param value The {@code Date} value to check.
      * @param compare The {@code Date} to compare the value to.
      * @param timeZone The Time Zone used to compare the dates, system default if null.
      * @return Zero if the weeks are equal, -1 if first
      * parameter's week is less than the seconds and +1 if the first
      * parameter's week is greater than.
      */
     public int compareWeeks(final Date value, final Date compare, final TimeZone timeZone) {
         final Calendar calendarValue = getCalendar(value, timeZone);
         final Calendar calendarCompare = getCalendar(compare, timeZone);
         return compare(calendarValue, calendarCompare, Calendar.WEEK_OF_YEAR);
     }
 
     /**
      * <p>Compare Years.</p>
      *
      * @param value The {@code Date} value to check.
      * @param compare The {@code Date} to compare the value to.
      * @param timeZone The Time Zone used to compare the dates, system default if null.
      * @return Zero if the years are equal, -1 if first
      * parameter's year is less than the seconds and +1 if the first
      * parameter's year is greater than.
      */
     public int compareYears(final Date value, final Date compare, final TimeZone timeZone) {
         final Calendar calendarValue = getCalendar(value, timeZone);
         final Calendar calendarCompare = getCalendar(compare, timeZone);
         return compare(calendarValue, calendarCompare, Calendar.YEAR);
     }
 
     /**
      * <p>Convert a {@code Date} to a {@link Calendar}.</p>
      *
      * @param value The date value to be converted.
      * @return The converted {@link Calendar}.
      */
     private Calendar getCalendar(final Date value, final TimeZone timeZone) {
         final Calendar calendar;
         if (timeZone != null) {
             calendar = Calendar.getInstance(timeZone);
         } else {
             calendar = Calendar.getInstance();
         }
         calendar.setTime(value);
         return calendar;
 
     }
 
     /**
      * <p>Returns the parsed {@code Date} unchanged.</p>
      *
      * @param value The parsed {@code Date} object created.
      * @param formatter The Format used to parse the value with.
      * @return The parsed value converted to a {@link Calendar}.
      */
     @Override
     protected Object processParsedValue(final Object value, final Format formatter) {
         return value;
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the default
      *    {@link Locale} and {@code TimeZone}.
      *
      * @param value The value validation is being performed on.
      * @return The parsed {@code Date} if valid or {@code null}
      *  if invalid.
      */
     public Date validate(final String value) {
         return (Date) parse(value, (String) null, (Locale) null, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the specified
      *    {@link Locale} and default {@code TimeZone}.
      *
      * @param value The value validation is being performed on.
      * @param locale The locale to use for the date format, system default if null.
      * @return The parsed {@code Date} if valid or {@code null} if invalid.
      */
     public Date validate(final String value, final Locale locale) {
         return (Date) parse(value, (String) null, locale, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the specified
      *    {@link Locale} and {@code TimeZone}.
      *
      * @param value The value validation is being performed on.
      * @param locale The locale to use for the date format, system default if null.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed {@code Date} if valid or {@code null} if invalid.
      */
     public Date validate(final String value, final Locale locale, final TimeZone timeZone) {
         return (Date) parse(value, (String) null, locale, timeZone);
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the specified
      *    <em>pattern</em> and default {@code TimeZone}.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against, or the
      *        default for the {@link Locale} if {@code null}.
      * @return The parsed {@code Date} if valid or {@code null} if invalid.
      */
     public Date validate(final String value, final String pattern) {
         return (Date) parse(value, pattern, (Locale) null, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the specified pattern
      *    and {@link Locale} and the default {@code TimeZone}.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against, or the
      *        default for the {@link Locale} if {@code null}.
      * @param locale The locale to use for the date format, system default if null.
      * @return The parsed {@code Date} if valid or {@code null} if invalid.
      */
     public Date validate(final String value, final String pattern, final Locale locale) {
         return (Date) parse(value, pattern, locale, (TimeZone) null);
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the specified
      *    pattern, and {@link Locale} and {@code TimeZone}.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against, or the
      *        default for the {@link Locale} if {@code null}.
      * @param locale The locale to use for the date format, system default if null.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed {@code Date} if valid or {@code null} if invalid.
      */
     public Date validate(final String value, final String pattern, final Locale locale, final TimeZone timeZone) {
         return (Date) parse(value, pattern, locale, timeZone);
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the specified
      *    <em>pattern</em> and {@code TimeZone}.
      *
      * @param value The value validation is being performed on.
      * @param pattern The pattern used to validate the value against, or the
      *        default for the {@link Locale} if {@code null}.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed {@code Date} if valid or {@code null} if invalid.
      */
     public Date validate(final String value, final String pattern, final TimeZone timeZone) {
         return (Date) parse(value, pattern, (Locale) null, timeZone);
     }
 
     /**
      * <p>Validate/convert a {@code Date} using the specified
      *    {@code TimeZone} and default {@link Locale}.
      *
      * @param value The value validation is being performed on.
      * @param timeZone The Time Zone used to parse the date, system default if null.
      * @return The parsed {@code Date} if valid or {@code null} if invalid.
      */
     public Date validate(final String value, final TimeZone timeZone) {
         return (Date) parse(value, (String) null, (Locale) null, timeZone);
     }
 
 }