/*
 * 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.beanutils.converters;

import java.util.Date;
import java.util.Locale;
import java.util.Calendar;
import java.util.TimeZone;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.text.ParsePosition;
import org.apache.commons.beanutils.ConversionException;

/**
 * {@link org.apache.commons.beanutils.Converter} implementaion
 * that handles conversion to and from <b>date/time</b> objects.
 * <p>
 * This implementation handles conversion for the following
 * <i>date/time</i> types.
 * <ul>
 *     <li><code>java.util.Date</code></li>
 *     <li><code>java.util.Calendar</code></li>
 *     <li><code>java.sql.Date</code></li>
 *     <li><code>java.sql.Time</code></li>
 *     <li><code>java.sql.Timestamp</code></li>
 * </ul>
 *
 * <h3>String Conversions (to and from)</h3>
 * This class provides a number of ways in which date/time
 * conversions to/from Strings can be achieved:
 * <ul>
 *    <li>Using the SHORT date format for the default Locale, configure using:</li>
 *        <ul>
 *           <li><code>setUseLocaleFormat(true)</code></li>
 *        </ul>
 *    <li>Using the SHORT date format for a specified Locale, configure using:</li>
 *        <ul>
 *           <li><code>setLocale(Locale)</code></li>
 *        </ul>
 *    <li>Using the specified date pattern(s) for the default Locale, configure using:</li>
 *        <ul>
 *           <li>Either <code>setPattern(String)</code> or
 *                      <code>setPatterns(String[])</code></li>
 *        </ul>
 *    <li>Using the specified date pattern(s) for a specified Locale, configure using:</li>
 *        <ul>
 *           <li><code>setPattern(String)</code> or
 *                    <code>setPatterns(String[]) and...</code></li>
 *           <li><code>setLocale(Locale)</code></li>
 *        </ul>
 *    <li>If none of the above are configured the
 *        <code>toDate(String)</code> method is used to convert
 *        from String to Date and the Dates's
 *        <code>toString()</code> method used to convert from
 *        Date to String.</li>
 * </ul>
 *
 * <p>
 * The <b>Time Zone</b> to use with the date format can be specified
 * using the <code>setTimeZone()</code> method.
 *
 * @version $Revision: 640131 $ $Date: 2008-03-23 02:10:31 +0000 (Sun, 23 Mar 2008) $
 * @since 1.8.0
 */
public abstract class DateTimeConverter extends AbstractConverter {

    private String[] patterns;
    private String displayPatterns;
    private Locale locale;
    private TimeZone timeZone;
    private boolean useLocaleFormat;


    // ----------------------------------------------------------- Constructors

    /**
     * Construct a Date/Time <i>Converter</i> that throws a
     * <code>ConversionException</code> if an error occurs.
     */
    public DateTimeConverter() {
        super();
    }

    /**
     * Construct a Date/Time <i>Converter</i> that returns a default
     * value if an error occurs.
     *
     * @param defaultValue The default value to be returned
     * if the value to be converted is missing or an error
     * occurs converting the value.
     */
    public DateTimeConverter(Object defaultValue) {
        super(defaultValue);
    }


    // --------------------------------------------------------- Public Methods

    /**
     * Indicate whether conversion should use a format/pattern or not.
     *
     * @param useLocaleFormat <code>true</code> if the format
     * for the locale should be used, otherwise <code>false</code>
     */
    public void setUseLocaleFormat(boolean useLocaleFormat) {
        this.useLocaleFormat = useLocaleFormat;
    }

    /**
     * Return the Time Zone to use when converting dates
     * (or <code>null</code> if none specified.
     *
     * @return The Time Zone.
     */
    public TimeZone getTimeZone() {
        return timeZone;
    }

    /**
     * Set the Time Zone to use when converting dates.
     *
     * @param timeZone The Time Zone.
     */
    public void setTimeZone(TimeZone timeZone) {
        this.timeZone = timeZone;
    }

    /**
     * Return the Locale for the <i>Converter</i>
     * (or <code>null</code> if none specified).
     *
     * @return The locale to use for conversion
     */
    public Locale getLocale() {
        return locale;
    }

    /**
     * Set the Locale for the <i>Converter</i>.
     *
     * @param locale The Locale.
     */
    public void setLocale(Locale locale) {
        this.locale = locale;
        setUseLocaleFormat(true);
    }

    /**
     * Set a date format pattern to use to convert
     * dates to/from a <code>java.lang.String</code>.
     *
     * @see SimpleDateFormat
     * @param pattern The format pattern.
     */
    public void setPattern(String pattern) {
        setPatterns(new String[] {pattern});
    }

    /**
     * Return the date format patterns used to convert
     * dates to/from a <code>java.lang.String</code>
     * (or <code>null</code> if none specified).
     *
     * @see SimpleDateFormat
     * @return Array of format patterns.
     */
    public String[] getPatterns() {
        return patterns; 
    }

    /**
     * Set the date format patterns to use to convert
     * dates to/from a <code>java.lang.String</code>.
     *
     * @see SimpleDateFormat
     * @param patterns Array of format patterns.
     */
    public void setPatterns(String[] patterns) {
        this.patterns = patterns;
        if (patterns != null && patterns.length > 1) {
            StringBuffer buffer = new StringBuffer();
            for (int i = 0; i < patterns.length; i++) {
                if (i > 0) {
                    buffer.append(", ");
                }
                buffer.append(patterns[i]);
            }
            displayPatterns = buffer.toString();
        }
        setUseLocaleFormat(true);
    }

    // ------------------------------------------------------ Protected Methods

    /**
     * Convert an input Date/Calendar object into a String.
     * <p>
     * <b>N.B.</b>If the converter has been configured to with
     * one or more patterns (using <code>setPatterns()</code>), then
     * the first pattern will be used to format the date into a String.
     * Otherwise the default <code>DateFormat</code> for the default locale
     * (and <i>style</i> if configured) will be used.
     *
     * @param value The input value to be converted
     * @return the converted String value.
     * @throws Throwable if an error occurs converting to a String
     */
    protected String convertToString(Object value) throws Throwable {

        Date date = null;
        if (value instanceof Date) {
            date = (Date)value;
        } else if (value instanceof Calendar) {
            date = ((Calendar)value).getTime();
        } else if (value instanceof Long) {
            date = new Date(((Long)value).longValue());
        }

        String result = null;
        if (useLocaleFormat && date != null) {
            DateFormat format = null;
            if (patterns != null && patterns.length > 0) {
                format = getFormat(patterns[0]);
            } else {
                format = getFormat(locale, timeZone);
            }
            logFormat("Formatting", format);
            result = format.format(date);
            if (log().isDebugEnabled()) {
                log().debug("    Converted  to String using format '" + result + "'");
            }
        } else {
            result = value.toString();
            if (log().isDebugEnabled()) {
                log().debug("    Converted  to String using toString() '" + result + "'");
             }
        }
        return result;
    }

    /**
     * Convert the input object into a Date object of the
     * specified type.
     * <p>
     * This method handles conversions between the following
     * types:
     * <ul>
     *     <li><code>java.util.Date</code></li>
     *     <li><code>java.util.Calendar</code></li>
     *     <li><code>java.sql.Date</code></li>
     *     <li><code>java.sql.Time</code></li>
     *     <li><code>java.sql.Timestamp</code></li>
     * </ul>
     *
     * It also handles conversion from a <code>String</code> to
     * any of the above types.
     * <p>
     *
     * For <code>String</code> conversion, if the converter has been configured
     * with one or more patterns (using <code>setPatterns()</code>), then
     * the conversion is attempted with each of the specified patterns.
     * Otherwise the default <code>DateFormat</code> for the default locale
     * (and <i>style</i> if configured) will be used.
     *
     * @param targetType Data type to which this value should be converted.
     * @param value The input value to be converted.
     * @return The converted value.
     * @throws Exception if conversion cannot be performed successfully
     */
    protected Object convertToType(Class targetType, Object value) throws Exception {

        Class sourceType = value.getClass();

        // Handle java.sql.Timestamp
        if (value instanceof java.sql.Timestamp) {

            // ---------------------- JDK 1.3 Fix ----------------------
            // N.B. Prior to JDK 1.4 the Timestamp's getTime() method
            //      didn't include the milliseconds. The following code
            //      ensures it works consistently accross JDK versions
            java.sql.Timestamp timestamp = (java.sql.Timestamp)value;
            long timeInMillis = ((timestamp.getTime() / 1000) * 1000);
            timeInMillis += timestamp.getNanos() / 1000000;
            // ---------------------- JDK 1.3 Fix ----------------------
            return toDate(targetType, timeInMillis);
        }

        // Handle Date (includes java.sql.Date & java.sql.Time)
        if (value instanceof Date) {
            Date date = (Date)value;
            return toDate(targetType, date.getTime());
        }

        // Handle Calendar
        if (value instanceof Calendar) {
            Calendar calendar = (Calendar)value;
            return toDate(targetType, calendar.getTime().getTime());
        }

        // Handle Long
        if (value instanceof Long) {