/*
    * 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.beanutils2.locale.converters;
  
  import java.text.DateFormat;
  import java.text.DateFormatSymbols;
  import java.text.ParseException;
  import java.text.ParsePosition;
  import java.text.SimpleDateFormat;
  import java.util.Calendar;
  import java.util.Date;
  import java.util.Locale;
  
  import org.apache.commons.beanutils2.ConversionException;
  import org.apache.commons.beanutils2.locale.BaseLocaleConverter;
  import org.apache.commons.beanutils2.locale.LocaleConverter;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /**
   * Standard {@link org.apache.commons.beanutils2.locale.LocaleConverter} implementation that converts an incoming locale-sensitive String into a
   * {@link java.util.Date} object, optionally using a default value or throwing a {@link org.apache.commons.beanutils2.ConversionException} if a conversion error
   * occurs.
   *
   * @param <D> The Date type.
   */
  public class DateLocaleConverter<D extends Date> extends BaseLocaleConverter<D> {
  
      /**
       * Builds instances of {@link DateLocaleConverter}.
       *
       * @param <B> The builder type.
       * @param <D> The Date type.
       */
      public static class Builder<B extends Builder<B, D>, D extends Date> extends BaseLocaleConverter.Builder<B, D> {
  
          /** Should the date conversion be lenient? */
          private boolean lenient;
  
          /**
           * Gets a new instance.
           * <p>
           * Defaults construct a {@link LocaleConverter} that will throw a {@link ConversionException} if a conversion error occurs. The locale is the default
           * locale for this instance of the Java Virtual Machine and an unlocalized pattern is used for the conversion.
           * </p>
           *
           * @return a new instance.
           */
          @Override
          public DateLocaleConverter<D> get() {
              return new DateLocaleConverter<>(defaultValue, locale, pattern, useDefault || defaultValue != null, localizedPattern, lenient);
          }
  
          /**
           * Tests whether date formatting is lenient.
           *
           * @return true if the {@code DateFormat} used for formatting is lenient
           * @see java.text.DateFormat#isLenient()
           */
          public boolean isLenient() {
              return lenient;
          }
  
          /**
           * Sets the leniency policy.
           *
           * @param lenient the leniency policy.
           * @return {@code this} instance.
           */
          public B setLenient(final boolean lenient) {
              this.lenient = lenient;
              return asThis();
          }
  
      }
  
      /**
       * Default Pattern Characters
       */
      private static final String DEFAULT_PATTERN_CHARS = DateLocaleConverter.initDefaultChars();
  
      /** All logging goes through this logger */
      private static final Log LOG = LogFactory.getLog(DateLocaleConverter.class);
  
     /**
      * Constructs a new builder.
      *
      * @param <B> The builder type.
      * @param <D> The Date type.
      * @return a new builder.
      */
     @SuppressWarnings("unchecked")
     public static <B extends Builder<B, D>, D extends Date> B builder() {
         return (B) new Builder<>();
     }
 
     /**
      * This method is called at class initialization time to define the value for constant member DEFAULT_PATTERN_CHARS. All other methods needing this data
      * should just read that constant.
      */
     private static String initDefaultChars() {
         return new DateFormatSymbols(Locale.US).getLocalPatternChars();
     }
 
     /** Should the date conversion be lenient? */
     private final boolean isLenient;
 
     /**
      * Constructs a new instance.
      *
      * @param defaultValue default value.
      * @param locale       locale.
      * @param pattern      pattern.
      * @param useDefault   use the default.
      * @param locPattern   localized pattern.
      * @param lenient      leniency policy.
      */
     protected DateLocaleConverter(final D defaultValue, final Locale locale, final String pattern, final boolean useDefault, final boolean locPattern,
             final boolean lenient) {
         super(defaultValue, locale, pattern, useDefault, locPattern);
         this.isLenient = lenient;
     }
 
     /**
      * Converts a pattern from a localized format to the default format.
      *
      * @param locale           The locale
      * @param localizedPattern The pattern in 'local' symbol format
      * @return pattern in 'default' symbol format
      */
     private String convertLocalizedPattern(final String localizedPattern, final Locale locale) {
         if (localizedPattern == null) {
             return null;
         }
 
         // Note that this is a little obtuse.
         // However, it is the best way that anyone can come up with
         // that works with some 1.4 series JVM.
 
         // Get the symbols for the localized pattern
         final DateFormatSymbols localizedSymbols = new DateFormatSymbols(locale);
         final String localChars = localizedSymbols.getLocalPatternChars();
 
         if (DEFAULT_PATTERN_CHARS.equals(localChars)) {
             return localizedPattern;
         }
 
         // Convert the localized pattern to default
         String convertedPattern = null;
         try {
             convertedPattern = convertPattern(localizedPattern, localChars, DEFAULT_PATTERN_CHARS);
         } catch (final Exception ex) {
             if (LOG.isDebugEnabled()) {
                 LOG.debug("Converting pattern '" + localizedPattern + "' for " + locale, ex);
             }
         }
         return convertedPattern;
     }
 
     /**
      * Converts a Pattern from one character set to another.
      */
     private String convertPattern(final String pattern, final String fromChars, final String toChars) {
         final StringBuilder converted = new StringBuilder();
         boolean quoted = false;
 
         for (int i = 0; i < pattern.length(); ++i) {
             char thisChar = pattern.charAt(i);
             if (quoted) {
                 if (thisChar == '\'') {
                     quoted = false;
                 }
             } else if (thisChar == '\'') {
                 quoted = true;
             } else if (thisChar >= 'a' && thisChar <= 'z' || thisChar >= 'A' && thisChar <= 'Z') {
                 final int index = fromChars.indexOf(thisChar);
                 if (index == -1) {
                     throw new IllegalArgumentException("Illegal pattern character '" + thisChar + "'");
                 }
                 thisChar = toChars.charAt(index);
             }
             converted.append(thisChar);
         }
 
         if (quoted) {
             throw new IllegalArgumentException("Unfinished quote in pattern");
         }
 
         return converted.toString();
     }
 
     /**
      * Tests whether date formatting is lenient.
      *
      * @return true if the {@code DateFormat} used for formatting is lenient
      * @see java.text.DateFormat#isLenient()
      */
     public boolean isLenient() {
         return isLenient;
     }
 
     /**
      * Convert the specified locale-sensitive input object into an output object of the specified type.
      *
      * @param value   The input object to be converted
      * @param pattern The pattern is used for the conversion
      * @return the converted Date value
      * @throws ConversionException if conversion cannot be performed successfully
      * @throws ParseException      if an error occurs parsing
      */
     @Override
     protected D parse(final Object value, String pattern) throws ParseException {
         // Handle Date
         if (value instanceof Date) {
             return (D) value;
         }
 
         // Handle Calendar
         if (value instanceof Calendar) {
             return (D) ((Calendar) value).getTime();
         }
 
         if (localizedPattern) {
             pattern = convertLocalizedPattern(pattern, locale);
         }
 
         // Create Formatter - use default if pattern is null
         final DateFormat formatter = pattern == null ? DateFormat.getDateInstance(DateFormat.SHORT, locale) : new SimpleDateFormat(pattern, locale);
         formatter.setLenient(isLenient);
 
         // Parse the Date
         final ParsePosition pos = new ParsePosition(0);
         final String strValue = value.toString();
         final Object parsedValue = formatter.parseObject(strValue, pos);
         if (pos.getErrorIndex() > -1) {
             throw ConversionException.format("Error parsing date '%s' at position = %s", value, pos.getErrorIndex());
         }
         if (pos.getIndex() < strValue.length()) {
             throw ConversionException.format("Date '%s' contains unparsed characters from position = %s", value, pos.getIndex());
         }
 
         return (D) parsedValue;
     }
 
 }