/*
    * 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.text;
  
  import java.text.Format;
  import java.text.MessageFormat;
  import java.text.ParsePosition;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Locale;
  import java.util.Locale.Category;
  import java.util.Map;
  import java.util.Objects;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.text.matcher.StringMatcherFactory;
  
  /**
   * Extends {@link java.text.MessageFormat} to allow pluggable/additional formatting
   * options for embedded format elements.
   * <p>
   * Client code should specify a registry
   * of {@code FormatFactory} instances associated with {@code String}
   * 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 {@link java.text.MessageFormat} can be overridden
   * at the format and/or format style level (see MessageFormat).  A "format element"
   * embedded in the message pattern is specified (<strong>()?</strong> signifies optionality):
   * </p>
   * <p>
   * {@code {}<em>argument-number</em><strong>(</strong>{@code ,}<em>format-name</em><b>
   * (</b>{@code ,}<em>format-style</em><strong>)?)?</strong>{@code }}
   * </p>
   *
   * <p>
   * <em>format-name</em> and <em>format-style</em> values are trimmed of surrounding whitespace
   * in the manner of {@link java.text.MessageFormat}.  If <em>format-name</em> denotes
   * {@code FormatFactory formatFactoryInstance} in {@code registry}, a {@code Format}
   * matching <em>format-name</em> and <em>format-style</em> is requested from
   * {@code formatFactoryInstance}.  If this is successful, the {@code Format}
   * found is used for this format element.
   * </p>
   *
   * <p><strong>NOTICE:</strong> 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} if called.
   * </p>
   *
   * <p>Limitations inherited from {@link java.text.MessageFormat}:</p>
   * <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}s, including {@code MessageFormat} and thus
   *     {@code ExtendedMessageFormat}, is not guaranteed.</li>
   * </ul>
   *
   * @since 1.0
   */
  public class ExtendedMessageFormat extends MessageFormat {
  
      /**
       * Serializable Object.
       */
      private static final long serialVersionUID = -2362048321261811743L;
  
      /**
       * The empty string.
       */
      private static final String EMPTY_PATTERN = StringUtils.EMPTY;
  
      /**
       * A comma.
       */
      private static final char START_FMT = ',';
  
      /**
       * A right curly bracket.
       */
      private static final char END_FE = '}';
  
      /**
       * A left curly bracket.
      */
     private static final char START_FE = '{';
 
     /**
      * A properly escaped character representing a single quote.
      */
     private static final char QUOTE = '\'';
 
     /**
      * To pattern string.
      */
     private String toPattern;
 
     /**
      * Our registry of FormatFactory.
      */
     private final Map<String, ? extends FormatFactory> registry;
 
     /**
      * Constructs 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(Category.FORMAT));
     }
 
     /**
      * Constructs 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);
     }
 
     /**
      * Constructs 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(EMPTY_PATTERN);
         setLocale(locale);
         this.registry = registry != null ? Collections.unmodifiableMap(new HashMap<>(registry)) : null;
         applyPattern(pattern);
     }
 
     /**
      * Constructs 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(Category.FORMAT), registry);
     }
 
     /**
      * Consumes a quoted string, adding it to {@code appendTo} if specified.
      *
      * @param pattern  pattern to parse.
      * @param pos      current parse position.
      * @param appendTo optional StringBuilder to append.
      */
     private void appendQuotedString(final String pattern, final ParsePosition pos, final StringBuilder appendTo) {
         assert pattern.toCharArray()[pos.getIndex()] == QUOTE : "Quoted string must start with quote character";
         // handle quote character at the beginning of the string
         if (appendTo != null) {
             appendTo.append(QUOTE);
         }
         next(pos);
         final int start = pos.getIndex();
         final char[] c = pattern.toCharArray();
         for (int i = pos.getIndex(); i < pattern.length(); i++) {
             switch (c[pos.getIndex()]) {
             case QUOTE:
                 next(pos);
                 if (appendTo != null) {
                     appendTo.append(c, start, pos.getIndex() - start);
                 }
                 return;
             default:
                 next(pos);
             }
         }
         throw new IllegalArgumentException("Unterminated quoted string at position " + start);
     }
 
     /**
      * Applies the specified pattern.
      *
      * @param pattern String.
      * @throws IllegalArgumentException in case of a bad pattern.
      */
     @Override
     public final void applyPattern(final String pattern) {
         if (registry == null) {
             super.applyPattern(pattern);
             toPattern = super.toPattern();
             return;
         }
         final ArrayList<Format> foundFormats = new ArrayList<>();
         final ArrayList<String> foundDescriptions = new ArrayList<>();
         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);
                 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);
                 final int foundFormatsSize = foundFormats.size();
                 if (foundFormatsSize != fmtCount) {
                     throw new IllegalArgumentException("Format elements do not match format count: " + foundFormatsSize + " != " + fmtCount);
                 }
                 final int foundDescriptionsSize = foundDescriptions.size();
                 if (foundDescriptionsSize != fmtCount) {
                     throw new IllegalArgumentException("Format descriptions do not match format count: " + foundDescriptionsSize + " != " + 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 Format f : foundFormats) {
                 if (f != null) {
                     origFormats[i] = f;
                 }
                 i++;
             }
             super.setFormats(origFormats);
         }
     }
 
     /**
      * Tests whether the specified Collection contains non-null elements.
      *
      * @param coll to check.
      * @return {@code true} if some Object was found, {@code false} otherwise.
      */
     private boolean containsElements(final Collection<?> coll) {
         if (coll == null || coll.isEmpty()) {
             return false;
         }
         return coll.stream().anyMatch(Objects::nonNull);
     }
 
     @Override
     public boolean equals(final Object obj) {
         if (this == obj) {
             return true;
         }
         if (!super.equals(obj)) {
             return false;
         }
         if (!(obj instanceof ExtendedMessageFormat)) {
             return false;
         }
         final ExtendedMessageFormat other = (ExtendedMessageFormat) obj;
         return Objects.equals(registry, other.registry) && Objects.equals(toPattern, other.toPattern);
     }
 
     /**
      * Gets 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;
     }
 
     /**
      * Consumes quoted string only.
      *
      * @param pattern pattern to parse.
      * @param pos current parse position.
      */
     private void getQuotedString(final String pattern, final ParsePosition pos) {
         appendQuotedString(pattern, pos, null);
     }
 
     @Override
     public int hashCode() {
         final int prime = 31;
         final int result = super.hashCode();
         return prime * result + Objects.hash(registry, toPattern);
     }
 
     /**
      * Inserts 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);
                 break;
             case START_FE:
                 depth++;
                 sb.append(START_FE).append(readArgumentIndex(pattern, next(pos)));
                 // do not look for custom patterns when they are embedded, e.g. in a choice
                 if (depth == 1) {
                     fe++;
                     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();
     }
 
     /**
      * Advances parse position by 1.
      *
      * @param pos ParsePosition.
      * @return {@code pos}.
      */
     private ParsePosition next(final ParsePosition pos) {
         pos.setIndex(pos.getIndex() + 1);
         return pos;
     }
 
     /**
      * Parses 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;
         while (pos.getIndex() < pattern.length()) {
             switch (pattern.charAt(pos.getIndex())) {
             case START_FE:
                 depth++;
                 next(pos);
                 break;
             case END_FE:
                 depth--;
                 if (depth == 0) {
                     return pattern.substring(text, pos.getIndex());
                 }
                 next(pos);
                 break;
             case QUOTE:
                 getQuotedString(pattern, pos);
                 break;
             default:
                 next(pos);
                 break;
             }
         }
         throw new IllegalArgumentException(
                 "Unterminated format element at position " + start);
     }
 
     /**
      * Reads 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);
                 if (pos.getIndex() >= pattern.length()) {
                     break;
                 }
                 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);
     }
 
     /**
      * Consumes whitespace from the current parse position.
      *
      * @param pattern String to read.
      * @param pos current position.
      */
     private void seekNonWs(final String pattern, final ParsePosition pos) {
         final char[] buffer = pattern.toCharArray();
         while (pos.getIndex() < buffer.length) {
             final int len = StringMatcherFactory.INSTANCE.splitMatcher().isMatch(buffer, pos.getIndex(), 0, buffer.length);
             if (len == 0) {
                 break;
             }
             pos.setIndex(pos.getIndex() + len);
         }
     }
 
     /**
      * Throws UnsupportedOperationException, see class Javadoc for details.
      *
      * @param formatElementIndex format element index.
      * @param newFormat          The new format.
      * @throws UnsupportedOperationException always thrown since this isn't supported by {@link ExtendedMessageFormat}.
      */
     @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 always thrown since this isn't supported by {@link ExtendedMessageFormat}.
      */
     @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 always thrown since this isn't supported by {@link ExtendedMessageFormat}.
      */
     @Override
     public void setFormats(final Format[] newFormats) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Throws UnsupportedOperationException - see class Javadoc for details.
      *
      * @param newFormats new formats
      * @throws UnsupportedOperationException always thrown since this isn't supported by {@link ExtendedMessageFormat}
      */
     @Override
     public void setFormatsByArgumentIndex(final Format[] newFormats) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String toPattern() {
         return toPattern;
     }
 }