/*
    * 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.lang3.text;
  
  import java.text.Format;
  import java.text.MessageFormat;
  import java.text.ParsePosition;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.Locale;
  import java.util.Map;
  
  import org.apache.commons.lang3.ObjectUtils;
  import org.apache.commons.lang3.Validate;
  
  /**
   * Extends <code>java.text.MessageFormat</code> to allow pluggable/additional formatting
   * options for embedded format elements.  Client code should specify a registry
   * of <code>FormatFactory</code> instances associated with <code>String</code>
   * format names.  This registry will be consulted when the format elements are
   * parsed from the message pattern.  In this way custom patterns can be specified,
   * and the formats supported by <code>java.text.MessageFormat</code> can be overridden
   * at the format and/or format style level (see MessageFormat).  A "format element"
   * embedded in the message pattern is specified (<b>()?</b> signifies optionality):<br />
   * <code>{</code><i>argument-number</i><b>(</b><code>,</code><i>format-name</i><b>
   * (</b><code>,</code><i>format-style</i><b>)?)?</b><code>}</code>
   *
   * <p>
   * <i>format-name</i> and <i>format-style</i> values are trimmed of surrounding whitespace
   * in the manner of <code>java.text.MessageFormat</code>.  If <i>format-name</i> denotes
   * <code>FormatFactory formatFactoryInstance</code> in <code>registry</code>, a <code>Format</code>
   * matching <i>format-name</i> and <i>format-style</i> is requested from
   * <code>formatFactoryInstance</code>.  If this is successful, the <code>Format</code>
   * found is used for this format element.
   * </p>
   *
   * <p><b>NOTICE:</b> The various subformat mutator methods are considered unnecessary; they exist on the parent
   * class to allow the type of customization which it is the job of this class to provide in
   * a configurable fashion.  These methods have thus been disabled and will throw
   * <code>UnsupportedOperationException</code> if called.
   * </p>
   *
   * <p>Limitations inherited from <code>java.text.MessageFormat</code>:
   * <ul>
   * <li>When using "choice" subformats, support for nested formatting instructions is limited
   *     to that provided by the base class.</li>
   * <li>Thread-safety of <code>Format</code>s, including <code>MessageFormat</code> and thus
   *     <code>ExtendedMessageFormat</code>, is not guaranteed.</li>
   * </ul>
   * </p>
   *
   * @since 2.4
   * @version $Id: ExtendedMessageFormat.java 1436770 2013-01-22 07:09:45Z ggregory $
   */
  public class ExtendedMessageFormat extends MessageFormat {
      private static final long serialVersionUID = -2362048321261811743L;
      private static final int HASH_SEED = 31;
  
      private static final String DUMMY_PATTERN = "";
      private static final String ESCAPED_QUOTE = "''";
      private static final char START_FMT = ',';
      private static final char END_FE = '}';
      private static final char START_FE = '{';
      private static final char QUOTE = '\'';
  
      private String toPattern;
      private final Map<String, ? extends FormatFactory> registry;
  
      /**
       * Create a new ExtendedMessageFormat for the default locale.
       *
       * @param pattern  the pattern to use, not null
       * @throws IllegalArgumentException in case of a bad pattern.
       */
      public ExtendedMessageFormat(final String pattern) {
          this(pattern, Locale.getDefault());
      }
  
      /**
       * Create a new ExtendedMessageFormat.
       *
       * @param pattern  the pattern to use, not null
       * @param locale  the locale to use, not null
       * @throws IllegalArgumentException in case of a bad pattern.
      */
     public ExtendedMessageFormat(final String pattern, final Locale locale) {
         this(pattern, locale, null);
     }
 
     /**
      * Create a new ExtendedMessageFormat for the default locale.
      *
      * @param pattern  the pattern to use, not null
      * @param registry  the registry of format factories, may be null
      * @throws IllegalArgumentException in case of a bad pattern.
      */
     public ExtendedMessageFormat(final String pattern, final Map<String, ? extends FormatFactory> registry) {
         this(pattern, Locale.getDefault(), registry);
     }
 
     /**
      * Create a new ExtendedMessageFormat.
      *
      * @param pattern  the pattern to use, not null
      * @param locale  the locale to use, not null
      * @param registry  the registry of format factories, may be null
      * @throws IllegalArgumentException in case of a bad pattern.
      */
     public ExtendedMessageFormat(final String pattern, final Locale locale, final Map<String, ? extends FormatFactory> registry) {
         super(DUMMY_PATTERN);
         setLocale(locale);
         this.registry = registry;
         applyPattern(pattern);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String toPattern() {
         return toPattern;
     }
 
     /**
      * Apply the specified pattern.
      *
      * @param pattern String
      */
     @Override
     public final void applyPattern(final String pattern) {
         if (registry == null) {
             super.applyPattern(pattern);
             toPattern = super.toPattern();
             return;
         }
         final ArrayList<Format> foundFormats = new ArrayList<Format>();
         final ArrayList<String> foundDescriptions = new ArrayList<String>();
         final StringBuilder stripCustom = new StringBuilder(pattern.length());
 
         final ParsePosition pos = new ParsePosition(0);
         final char[] c = pattern.toCharArray();
         int fmtCount = 0;
         while (pos.getIndex() < pattern.length()) {
             switch (c[pos.getIndex()]) {
             case QUOTE:
                 appendQuotedString(pattern, pos, stripCustom, true);
                 break;
             case START_FE:
                 fmtCount++;
                 seekNonWs(pattern, pos);
                 final int start = pos.getIndex();
                 final int index = readArgumentIndex(pattern, next(pos));
                 stripCustom.append(START_FE).append(index);
                 seekNonWs(pattern, pos);
                 Format format = null;
                 String formatDescription = null;
                 if (c[pos.getIndex()] == START_FMT) {
                     formatDescription = parseFormatDescription(pattern,
                             next(pos));
                     format = getFormat(formatDescription);
                     if (format == null) {
                         stripCustom.append(START_FMT).append(formatDescription);
                     }
                 }
                 foundFormats.add(format);
                 foundDescriptions.add(format == null ? null : formatDescription);
                 Validate.isTrue(foundFormats.size() == fmtCount);
                 Validate.isTrue(foundDescriptions.size() == fmtCount);
                 if (c[pos.getIndex()] != END_FE) {
                     throw new IllegalArgumentException(
                             "Unreadable format element at position " + start);
                 }
                 //$FALL-THROUGH$
             default:
                 stripCustom.append(c[pos.getIndex()]);
                 next(pos);
             }
         }
         super.applyPattern(stripCustom.toString());
         toPattern = insertFormats(super.toPattern(), foundDescriptions);
         if (containsElements(foundFormats)) {
             final Format[] origFormats = getFormats();
             // only loop over what we know we have, as MessageFormat on Java 1.3
             // seems to provide an extra format element:
             int i = 0;
             for (final Iterator<Format> it = foundFormats.iterator(); it.hasNext(); i++) {
                 final Format f = it.next();
                 if (f != null) {
                     origFormats[i] = f;
                 }
             }
             super.setFormats(origFormats);
         }
     }
 
     /**
      * Throws UnsupportedOperationException - see class Javadoc for details.
      *
      * @param formatElementIndex format element index
      * @param newFormat the new format
      * @throws UnsupportedOperationException
      */
     @Override
     public void setFormat(final int formatElementIndex, final Format newFormat) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Throws UnsupportedOperationException - see class Javadoc for details.
      *
      * @param argumentIndex argument index
      * @param newFormat the new format
      * @throws UnsupportedOperationException
      */
     @Override
     public void setFormatByArgumentIndex(final int argumentIndex, final Format newFormat) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Throws UnsupportedOperationException - see class Javadoc for details.
      *
      * @param newFormats new formats
      * @throws UnsupportedOperationException
      */
     @Override
     public void setFormats(final Format[] newFormats) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Throws UnsupportedOperationException - see class Javadoc for details.
      *
      * @param newFormats new formats
      * @throws UnsupportedOperationException
      */
     @Override
     public void setFormatsByArgumentIndex(final Format[] newFormats) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Check if this extended message format is equal to another object.
      *
      * @param obj the object to compare to
      * @return true if this object equals the other, otherwise false
      */
     @Override
     public boolean equals(final Object obj) {
         if (obj == this) {
             return true;
         }
         if (obj == null) {
             return false;
         }
         if (!super.equals(obj)) {
             return false;
         }
         if (ObjectUtils.notEqual(getClass(), obj.getClass())) {
           return false;
         }
         final ExtendedMessageFormat rhs = (ExtendedMessageFormat)obj;
         if (ObjectUtils.notEqual(toPattern, rhs.toPattern)) {
             return false;
         }
         if (ObjectUtils.notEqual(registry, rhs.registry)) {
             return false;
         }
         return true;
     }
 
     /**
      * Return the hashcode.
      *
      * @return the hashcode
      */
     @Override
     public int hashCode() {
         int result = super.hashCode();
         result = HASH_SEED * result + ObjectUtils.hashCode(registry);
         result = HASH_SEED * result + ObjectUtils.hashCode(toPattern);
         return result;
     }
 
     /**
      * Get a custom format from a format description.
      *
      * @param desc String
      * @return Format
      */
     private Format getFormat(final String desc) {
         if (registry != null) {
             String name = desc;
             String args = null;
             final int i = desc.indexOf(START_FMT);
             if (i > 0) {
                 name = desc.substring(0, i).trim();
                 args = desc.substring(i + 1).trim();
             }
             final FormatFactory factory = registry.get(name);
             if (factory != null) {
                 return factory.getFormat(name, args, getLocale());
             }
         }
         return null;
     }
 
     /**
      * Read the argument index from the current format element
      *
      * @param pattern pattern to parse
      * @param pos current parse position
      * @return argument index
      */
     private int readArgumentIndex(final String pattern, final ParsePosition pos) {
         final int start = pos.getIndex();
         seekNonWs(pattern, pos);
         final StringBuilder result = new StringBuilder();
         boolean error = false;
         for (; !error && pos.getIndex() < pattern.length(); next(pos)) {
             char c = pattern.charAt(pos.getIndex());
             if (Character.isWhitespace(c)) {
                 seekNonWs(pattern, pos);
                 c = pattern.charAt(pos.getIndex());
                 if (c != START_FMT && c != END_FE) {
                     error = true;
                     continue;
                 }
             }
             if ((c == START_FMT || c == END_FE) && result.length() > 0) {
                 try {
                     return Integer.parseInt(result.toString());
                 } catch (final NumberFormatException e) { // NOPMD
                     // we've already ensured only digits, so unless something
                     // outlandishly large was specified we should be okay.
                 }
             }
             error = !Character.isDigit(c);
             result.append(c);
         }
         if (error) {
             throw new IllegalArgumentException(
                     "Invalid format argument index at position " + start + ": "
                             + pattern.substring(start, pos.getIndex()));
         }
         throw new IllegalArgumentException(
                 "Unterminated format element at position " + start);
     }
 
     /**
      * Parse the format component of a format element.
      *
      * @param pattern string to parse
      * @param pos current parse position
      * @return Format description String
      */
     private String parseFormatDescription(final String pattern, final ParsePosition pos) {
         final int start = pos.getIndex();
         seekNonWs(pattern, pos);
         final int text = pos.getIndex();
         int depth = 1;
         for (; pos.getIndex() < pattern.length(); next(pos)) {
             switch (pattern.charAt(pos.getIndex())) {
             case START_FE:
                 depth++;
                 break;
             case END_FE:
                 depth--;
                 if (depth == 0) {
                     return pattern.substring(text, pos.getIndex());
                 }
                 break;
             case QUOTE:
                 getQuotedString(pattern, pos, false);
                 break;
             }
         }
         throw new IllegalArgumentException(
                 "Unterminated format element at position " + start);
     }
 
     /**
      * Insert formats back into the pattern for toPattern() support.
      *
      * @param pattern source
      * @param customPatterns The custom patterns to re-insert, if any
      * @return full pattern
      */
     private String insertFormats(final String pattern, final ArrayList<String> customPatterns) {
         if (!containsElements(customPatterns)) {
             return pattern;
         }
         final StringBuilder sb = new StringBuilder(pattern.length() * 2);
         final ParsePosition pos = new ParsePosition(0);
         int fe = -1;
         int depth = 0;
         while (pos.getIndex() < pattern.length()) {
             final char c = pattern.charAt(pos.getIndex());
             switch (c) {
             case QUOTE:
                 appendQuotedString(pattern, pos, sb, false);
                 break;
             case START_FE:
                 depth++;
                 if (depth == 1) {
                     fe++;
                     sb.append(START_FE).append(
                             readArgumentIndex(pattern, next(pos)));
                     final String customPattern = customPatterns.get(fe);
                     if (customPattern != null) {
                         sb.append(START_FMT).append(customPattern);
                     }
                 }
                 break;
             case END_FE:
                 depth--;
                 //$FALL-THROUGH$
             default:
                 sb.append(c);
                 next(pos);
             }
         }
         return sb.toString();
     }
 
     /**
      * Consume whitespace from the current parse position.
      *
      * @param pattern String to read
      * @param pos current position
      */
     private void seekNonWs(final String pattern, final ParsePosition pos) {
         int len = 0;
         final char[] buffer = pattern.toCharArray();
         do {
             len = StrMatcher.splitMatcher().isMatch(buffer, pos.getIndex());
             pos.setIndex(pos.getIndex() + len);
         } while (len > 0 && pos.getIndex() < pattern.length());
     }
 
     /**
      * Convenience method to advance parse position by 1
      *
      * @param pos ParsePosition
      * @return <code>pos</code>
      */
     private ParsePosition next(final ParsePosition pos) {
         pos.setIndex(pos.getIndex() + 1);
         return pos;
     }
 
     /**
      * Consume a quoted string, adding it to <code>appendTo</code> if
      * specified.
      *
      * @param pattern pattern to parse
      * @param pos current parse position
      * @param appendTo optional StringBuilder to append
      * @param escapingOn whether to process escaped quotes
      * @return <code>appendTo</code>
      */
     private StringBuilder appendQuotedString(final String pattern, final ParsePosition pos,
             final StringBuilder appendTo, final boolean escapingOn) {
         final int start = pos.getIndex();
         final char[] c = pattern.toCharArray();
         if (escapingOn && c[start] == QUOTE) {
             next(pos);
             return appendTo == null ? null : appendTo.append(QUOTE);
         }
         int lastHold = start;
         for (int i = pos.getIndex(); i < pattern.length(); i++) {
             if (escapingOn && pattern.substring(i).startsWith(ESCAPED_QUOTE)) {
                 appendTo.append(c, lastHold, pos.getIndex() - lastHold).append(
                         QUOTE);
                 pos.setIndex(i + ESCAPED_QUOTE.length());
                 lastHold = pos.getIndex();
                 continue;
             }
             switch (c[pos.getIndex()]) {
             case QUOTE:
                 next(pos);
                 return appendTo == null ? null : appendTo.append(c, lastHold,
                         pos.getIndex() - lastHold);
             default:
                 next(pos);
             }
         }
         throw new IllegalArgumentException(
                 "Unterminated quoted string at position " + start);
     }
 
     /**
      * Consume quoted string only
      *
      * @param pattern pattern to parse
      * @param pos current parse position
      * @param escapingOn whether to process escaped quotes
      */
     private void getQuotedString(final String pattern, final ParsePosition pos,
             final boolean escapingOn) {
         appendQuotedString(pattern, pos, null, escapingOn);
     }
 
     /**
      * Learn whether the specified Collection contains non-null elements.
      * @param coll to check
      * @return <code>true</code> if some Object was found, <code>false</code> otherwise.
      */
     private boolean containsElements(final Collection<?> coll) {
         if (coll == null || coll.isEmpty()) {
             return false;
         }
         for (final Object name : coll) {
             if (name != null) {
                 return true;
             }
         }
         return false;
     }
 }