content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed 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 com.android.internal.app;
  
  import android.annotation.IntRange;
  import android.annotation.UnsupportedAppUsage;
  import android.icu.text.ListFormatter;
  import android.icu.util.ULocale;
  import android.os.LocaleList;
  import android.text.TextUtils;
  
  import java.text.Collator;
  import java.util.Comparator;
  import java.util.Locale;
  
  /**
   * This class implements some handy methods to process with locales.
   */
  public class LocaleHelper {
  
      /**
       * Sentence-case (first character uppercased).
       *
       * <p>There is no good API available for this, not even in ICU.
       * We can revisit this if we get some ICU support later.</p>
       *
       * <p>There are currently several tickets requesting this feature:</p>
       * <ul>
       * <li>ICU needs to provide an easy way to titlecase only one first letter
       *   http://bugs.icu-project.org/trac/ticket/11729</li>
       * <li>Add "initial case"
       *    http://bugs.icu-project.org/trac/ticket/8394</li>
       * <li>Add code for initialCase, toTitlecase don't modify after Lt,
       *   avoid 49Ers, low-level language-specific casing
       *   http://bugs.icu-project.org/trac/ticket/10410</li>
       * <li>BreakIterator.getFirstInstance: Often you need to titlecase just the first
       *   word, and leave the rest of the string alone.  (closed as duplicate)
       *   http://bugs.icu-project.org/trac/ticket/8946</li>
       * </ul>
       *
       * <p>A (clunky) option with the current ICU API is:</p>
       * {{
       *   BreakIterator breakIterator = BreakIterator.getSentenceInstance(locale);
       *   String result = UCharacter.toTitleCase(locale,
       *       source, breakIterator, UCharacter.TITLECASE_NO_LOWERCASE);
       * }}
       *
       * <p>That also means creating a BreakIterator for each locale. Expensive...</p>
       *
       * @param str the string to sentence-case.
       * @param locale the locale used for the case conversion.
       * @return the string converted to sentence-case.
       */
      public static String toSentenceCase(String str, Locale locale) {
          if (str.isEmpty()) {
              return str;
          }
          final int firstCodePointLen = str.offsetByCodePoints(0, 1);
          return str.substring(0, firstCodePointLen).toUpperCase(locale)
                  + str.substring(firstCodePointLen);
      }
  
      /**
       * Normalizes a string for locale name search. Does case conversion for now,
       * but might do more in the future.
       *
       * <p>Warning: it is only intended to be used in searches by the locale picker.
       * Don't use it for other things, it is very limited.</p>
       *
       * @param str the string to normalize
       * @param locale the locale that might be used for certain operations (i.e. case conversion)
       * @return the string normalized for search
       */
      @UnsupportedAppUsage
      public static String normalizeForSearch(String str, Locale locale) {
          // TODO: tbd if it needs to be smarter (real normalization, remove accents, etc.)
          // If needed we might use case folding and ICU/CLDR's collation-based loose searching.
          // TODO: decide what should the locale be, the default locale, or the locale of the string.
          // Uppercase is better than lowercase because of things like sharp S, Greek sigma, ...
          return str.toUpperCase();
      }
  
      // For some locales we want to use a "dialect" form, for instance
      // "Dari" instead of "Persian (Afghanistan)", or "Moldavian" instead of "Romanian (Moldova)"
      private static boolean shouldUseDialectName(Locale locale) {
          final String lang = locale.getLanguage();
          return "fa".equals(lang) // Persian
                  || "ro".equals(lang) // Romanian
                  || "zh".equals(lang); // Chinese
      }
  
      /**
       * Returns the locale localized for display in the provided locale.
       *
       * @param locale the locale whose name is to be displayed.
       * @param displayLocale the locale in which to display the name.
       * @param sentenceCase true if the result should be sentence-cased
       * @return the localized name of the locale.
       */
      @UnsupportedAppUsage
      public static String getDisplayName(Locale locale, Locale displayLocale, boolean sentenceCase) {
          final ULocale displayULocale = ULocale.forLocale(displayLocale);
          String result = shouldUseDialectName(locale)
                  ? ULocale.getDisplayNameWithDialect(locale.toLanguageTag(), displayULocale)
                  : ULocale.getDisplayName(locale.toLanguageTag(), displayULocale);
          return sentenceCase ? toSentenceCase(result, displayLocale) : result;
      }
  
      /**
       * Returns the locale localized for display in the default locale.
       *
       * @param locale the locale whose name is to be displayed.
       * @param sentenceCase true if the result should be sentence-cased
       * @return the localized name of the locale.
       */
      public static String getDisplayName(Locale locale, boolean sentenceCase) {
          return getDisplayName(locale, Locale.getDefault(), sentenceCase);
      }
  
      /**
       * Returns a locale's country localized for display in the provided locale.
       *
       * @param locale the locale whose country will be displayed.
       * @param displayLocale the locale in which to display the name.
       * @return the localized country name.
       */
      @UnsupportedAppUsage
      public static String getDisplayCountry(Locale locale, Locale displayLocale) {
          final String languageTag = locale.toLanguageTag();
          final ULocale uDisplayLocale = ULocale.forLocale(displayLocale);
          final String country = ULocale.getDisplayCountry(languageTag, uDisplayLocale);
          final String numberingSystem = locale.getUnicodeLocaleType("nu");
          if (numberingSystem != null) {
              return String.format("%s (%s)", country,
                      ULocale.getDisplayKeywordValue(languageTag, "numbers", uDisplayLocale));
          } else {
              return country;
          }
      }
  
      /**
       * Returns a locale's country localized for display in the default locale.
       *
       * @param locale the locale whose country will be displayed.
       * @return the localized country name.
       */
      public static String getDisplayCountry(Locale locale) {
          return ULocale.getDisplayCountry(locale.toLanguageTag(), ULocale.getDefault());
      }
  
      /**
       * Returns the locale list localized for display in the provided locale.
       *
       * @param locales the list of locales whose names is to be displayed.
       * @param displayLocale the locale in which to display the names.
       *                      If this is null, it will use the default locale.
       * @param maxLocales maximum number of locales to display. Generates ellipsis after that.
       * @return the locale aware list of locale names
       */
      public static String getDisplayLocaleList(
              LocaleList locales, Locale displayLocale, @IntRange(from=1) int maxLocales) {
  
          final Locale dispLocale = displayLocale == null ? Locale.getDefault() : displayLocale;
  
          final boolean ellipsisNeeded = locales.size() > maxLocales;
          final int localeCount, listCount;
          if (ellipsisNeeded) {
              localeCount = maxLocales;
              listCount = maxLocales + 1;  // One extra slot for the ellipsis
          } else {
              listCount = localeCount = locales.size();
          }
          final String[] localeNames = new String[listCount];
          for (int i = 0; i < localeCount; i++) {
              localeNames[i] = LocaleHelper.getDisplayName(locales.get(i), dispLocale, false);
          }
          if (ellipsisNeeded) {
              // Theoretically, we want to extract this from ICU's Resource Bundle for
              // "Ellipsis/final", which seems to have different strings than the normal ellipsis for
              // Hong Kong Traditional Chinese (zh_Hant_HK) and Dzongkha (dz). But that has two
              // problems: it's expensive to extract it, and in case the output string becomes
              // automatically ellipsized, it can result in weird output.
              localeNames[maxLocales] = TextUtils.getEllipsisString(TextUtils.TruncateAt.END);
          }
  
          ListFormatter lfn = ListFormatter.getInstance(dispLocale);
          return lfn.format((Object[]) localeNames);
      }
  
      /**
       * Adds the likely subtags for a provided locale ID.
       *
       * @param locale the locale to maximize.
       * @return the maximized Locale instance.
       */
      public static Locale addLikelySubtags(Locale locale) {
          return libcore.icu.ICU.addLikelySubtags(locale);
      }
  
      /**
       * Locale-sensitive comparison for LocaleInfo.
       *
       * <p>It uses the label, leaving the decision on what to put there to the LocaleInfo.
       * For instance fr-CA can be shown as "français" as a generic label in the language selection,
       * or "français (Canada)" if it is a suggestion, or "Canada" in the country selection.</p>
       *
       * <p>Gives priority to suggested locales (to sort them at the top).</p>
       */
      public static final class LocaleInfoComparator implements Comparator<LocaleStore.LocaleInfo> {
          private final Collator mCollator;
          private final boolean mCountryMode;
          private static final String PREFIX_ARABIC = "\u0627\u0644"; // ALEF-LAM, ال
  
          /**
           * Constructor.
           *
           * @param sortLocale the locale to be used for sorting.
           */
          @UnsupportedAppUsage
          public LocaleInfoComparator(Locale sortLocale, boolean countryMode) {
              mCollator = Collator.getInstance(sortLocale);
              mCountryMode = countryMode;
          }
  
          /*
           * The Arabic collation should ignore Alef-Lam at the beginning (b/26277596)
           *
           * We look at the label's locale, not the current system locale.
           * This is because the name of the Arabic language itself is in Arabic,
           * and starts with Alef-Lam, no matter what the system locale is.
           */
          private String removePrefixForCompare(Locale locale, String str) {
              if ("ar".equals(locale.getLanguage()) && str.startsWith(PREFIX_ARABIC)) {
                  return str.substring(PREFIX_ARABIC.length());
              }
              return str;
          }
  
          /**
           * Compares its two arguments for order.
           *
           * @param lhs   the first object to be compared
           * @param rhs   the second object to be compared
           * @return  a negative integer, zero, or a positive integer as the first
           *          argument is less than, equal to, or greater than the second.
           */
          @UnsupportedAppUsage
          @Override
          public int compare(LocaleStore.LocaleInfo lhs, LocaleStore.LocaleInfo rhs) {
              // We don't care about the various suggestion types, just "suggested" (!= 0)
              // and "all others" (== 0)
              if (lhs.isSuggested() == rhs.isSuggested()) {
                  // They are in the same "bucket" (suggested / others), so we compare the text
                  return mCollator.compare(
                          removePrefixForCompare(lhs.getLocale(), lhs.getLabel(mCountryMode)),
                          removePrefixForCompare(rhs.getLocale(), rhs.getLabel(mCountryMode)));
              } else {
                  // One locale is suggested and one is not, so we put them in different "buckets"
                  return lhs.isSuggested() ? -1 : 1;
              }
          }
      }
  }
  