/*
 * 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.Locale;
import java.util.TimeZone;

/**
 * <strong>Time Validation</strong> and Conversion routines ({@code java.util.Calendar}).
 *
 * <p>This validator provides a number of methods for validating/converting
 *    a {@link String} time value to a {@code java.util.Calendar} 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> {@link Calendar} value for the time.</p>
 *
 * <p>Implementations of the {@code validate()} method are provided
 *    to create {@link Calendar} objects for different <em>time zones</em>
 *    if the system default is not appropriate.</p>
 *
 * <p>Alternatively the CalendarValidator's {@code adjustToTimeZone()} method
 *    can be used to adjust the {@code TimeZone} of the {@link Calendar}
 *    object afterwards.</p>
 *
 * <p>Once a value has been successfully converted the following
 *    methods can be used to perform various time comparison checks:</p>
 *    <ul>
 *       <li>{@code compareTime()} compares the hours, minutes, seconds
 *           and milliseconds of two calendars, returning 0, -1 or +1 indicating
 *           whether the first time is equal, before or after the second.</li>
 *       <li>{@code compareSeconds()} compares the hours, minutes and
 *           seconds of two times, returning 0, -1 or +1 indicating
 *           whether the first is equal to, before or after the second.</li>
 *       <li>{@code compareMinutes()} compares the hours and minutes
 *           two times, returning 0, -1 or +1 indicating
 *           whether the first is equal to, before or after the second.</li>
 *       <li>{@code compareHours()} compares the hours
 *           of two times, returning 0, -1 or +1 indicating
 *           whether the first is equal to, 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 TimeValidator extends AbstractCalendarValidator {

    private static final long serialVersionUID = 3494007492269691581L;

    private static final TimeValidator VALIDATOR = new TimeValidator();

    /**
     * Gets the singleton instance of this validator.
     *
     * @return A singleton instance of the TimeValidator.
     */
    public static TimeValidator getInstance() {
        return VALIDATOR;
    }

    /**
     * Constructs a <em>strict</em> instance with <em>short</em>
     * time style.
     */
    public TimeValidator() {
        this(true, DateFormat.SHORT);
    }

    /**
     * Constructs an instance with the specified <em>strict</em>
     * and <em>time style</em> parameters.
     *
     * @param strict {@code true} if strict
     *        {@code Format} parsing should be used.
     * @param timeStyle The time style to use for Locale validation.
     */
    public TimeValidator(final boolean strict, final int timeStyle) {
        super(strict, -1, timeStyle);
    }

    /**
     * Compare Hours.
     *
     * @param value The {@link Calendar} value to check.
     * @param compare The {@link Calendar} to compare the value to.
     * @return Zero if the hours are equal, -1 if first
     * parameter's hour is less than the seconds and +1 if the first
     * parameter's hour is greater than.
     */
    public int compareHours(final Calendar value, final Calendar compare) {
        return compareTime(value, compare, Calendar.HOUR_OF_DAY);
    }

    /**
     * Compare Minutes (hours and minutes).
     *
     * @param value The {@link Calendar} value to check.
     * @param compare The {@link Calendar} to compare the value to.
     * @return Zero if the hours are equal, -1 if first
     * parameter's minutes are less than the seconds and +1 if the first
     * parameter's minutes are greater than.
     */
    public int compareMinutes(final Calendar value, final Calendar compare) {
        return compareTime(value, compare, Calendar.MINUTE);
    }

    /**
     * Compare Seconds (hours, minutes and seconds).
     *
     * @param value The {@link Calendar} value to check.
     * @param compare The {@link Calendar} to compare the value to.
     * @return Zero if the hours are equal, -1 if first
     * parameter's seconds are less than the seconds and +1 if the first
     * parameter's seconds are greater than.
     */
    public int compareSeconds(final Calendar value, final Calendar compare) {
        return compareTime(value, compare, Calendar.SECOND);
    }

    /**
     * Compare Times (hour, minute, second and millisecond - not date).
     *
     * @param value The {@link Calendar} value to check.
     * @param compare The {@link Calendar} to compare the value to.
     * @return Zero if the hours are equal, -1 if first
     * time is less than the seconds and +1 if the first
     * time is greater than.
     */
    public int compareTime(final Calendar value, final Calendar compare) {
        return compareTime(value, compare, Calendar.MILLISECOND);
    }

    /**
     * Convert the parsed {@code Date} to a {@link Calendar}.
     *
     * @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 ((DateFormat) formatter).getCalendar();
    }

    /**
     * Validate/convert a time using the default {@link Locale}
     *    and {@code TimeZone}.
     *
     * @param value The value validation is being performed on.
     * @return The parsed {@link Calendar} if valid or {@code null}
     *  if invalid.
     */
    public Calendar validate(final String value) {
        return (Calendar) parse(value, (String) null, (Locale) null, (TimeZone) null);
    }

    /**
     * Validate/convert a time using the specified {@link Locale}
     *    default {@code TimeZone}.
     *
     * @param value The value validation is being performed on.
     * @param locale The locale to use for the time format, system default if null.
     * @return The parsed {@link Calendar} if valid or {@code null} if invalid.
     */
    public Calendar validate(final String value, final Locale locale) {
        return (Calendar) parse(value, (String) null, locale, (TimeZone) null);
    }

    /**
     * Validate/convert a time 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 time format, system default if null.
     * @param timeZone The Time Zone used to parse the time, system default if null.
     * @return The parsed {@link Calendar} if valid or {@code null} if invalid.
     */
    public Calendar validate(final String value, final Locale locale, final TimeZone timeZone) {
        return (Calendar) parse(value, (String) null, locale, timeZone);
    }

    /**
     * Validate/convert a time 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.
     * @return The parsed {@link Calendar} if valid or {@code null} if invalid.
     */
    public Calendar validate(final String value, final String pattern) {
        return (Calendar) parse(value, pattern, (Locale) null, (TimeZone) null);
    }

    /**
     * Validate/convert a time 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 {@link Calendar} if valid or {@code null} if invalid.
     */
    public Calendar validate(final String value, final String pattern, final Locale locale) {
        return (Calendar) parse(value, pattern, locale, (TimeZone) null);
    }

    /**
     * Validate/convert a time using the specified pattern, {@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 {@link Calendar} if valid or {@code null} if invalid.
     */
    public Calendar validate(final String value, final String pattern, final Locale locale, final TimeZone timeZone) {
        return (Calendar) parse(value, pattern, locale, timeZone);
    }

    /**
     * Validate/convert a time 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.
     * @param timeZone The Time Zone used to parse the time, system default if null.
     * @return The parsed {@link Calendar} if valid or {@code null} if invalid.
     */
    public Calendar validate(final String value, final String pattern, final TimeZone timeZone) {
        return (Calendar) parse(value, pattern, (Locale) null, timeZone);
    }

    /**
     * Validate/convert a time 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 time, system default if null.
     * @return The parsed {@link Calendar} if valid or {@code null} if invalid.
     */
    public Calendar validate(final String value, final TimeZone timeZone) {
        return (Calendar) parse(value, (String) null, (Locale) null, timeZone);
    }
}
