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 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package sun.util.cldr;

import static sun.util.locale.provider.LocaleProviderAdapter.Type;

import java.text.MessageFormat;

import java.util.Arrays;

import java.util.Locale;

import java.util.Objects;

import java.util.ResourceBundle;

import java.util.Set;

import java.util.TimeZone;

import java.util.stream.Collectors;

import sun.util.calendar.ZoneInfoFile;

import sun.util.locale.provider.LocaleProviderAdapter;

import sun.util.locale.provider.LocaleResources;

import sun.util.locale.provider.TimeZoneNameProviderImpl;

import sun.util.locale.provider.TimeZoneNameUtility;

/**

 * Concrete implementation of the

 * {@link java.util.spi.TimeZoneNameProvider TimeZoneNameProvider} class

 * for the CLDR LocaleProviderAdapter.

 *

 * @author Naoto Sato

 */

public class CLDRTimeZoneNameProviderImpl extends TimeZoneNameProviderImpl {

    private static final String NO_INHERITANCE_MARKER = "\u2205\u2205\u2205";

    private static class AVAILABLE_IDS {

        static final String[] INSTANCE =

            Arrays.stream(ZoneInfoFile.getZoneIds())

                .sorted()

                .toArray(String[]::new);

    }

    // display name array indexes

    private static final int INDEX_TZID         = 0;

    private static final int INDEX_STD_LONG     = 1;

    private static final int INDEX_STD_SHORT    = 2;

    private static final int INDEX_DST_LONG     = 3;

    private static final int INDEX_DST_SHORT    = 4;

    private static final int INDEX_GEN_LONG     = 5;

    private static final int INDEX_GEN_SHORT    = 6;

    public CLDRTimeZoneNameProviderImpl(Type type, Set<String> langtags) {

        super(type, langtags);

    }

    @Override

    protected String[] getDisplayNameArray(String id, Locale locale) {

        String tzid = TimeZoneNameUtility.canonicalTZID(id).orElse(id);

        String[] namesSuper = super.getDisplayNameArray(tzid, locale);

        if (Objects.nonNull(namesSuper)) {

            // CLDR's resource bundle has an translated entry for this id.

            // Fix up names if needed, either missing or no-inheritance

            namesSuper[INDEX_TZID] = id;

            // Check if standard long name exists. If not, try to retrieve the name

            // from language only locale resources. E.g., "Europe/London"

            // for en-GB only contains DST names

            if (!exists(namesSuper, INDEX_STD_LONG) && !locale.getCountry().isEmpty()) {

                String[] names =

                        getDisplayNameArray(id, Locale.forLanguageTag(locale.getLanguage()));

                if (exists(names, INDEX_STD_LONG)) {

                    namesSuper[INDEX_STD_LONG] = names[INDEX_STD_LONG];

                }

            }

            for(int i = INDEX_STD_LONG; i < namesSuper.length; i++) { // index 0 is the 'id' itself

                switch (namesSuper[i]) {

                case "":

                    // Fill in empty elements

                    deriveFallbackName(namesSuper, i, locale,

                            namesSuper[INDEX_DST_LONG].isEmpty());

                    break;

                case NO_INHERITANCE_MARKER:

                    // CLDR's "no inheritance marker"

                    namesSuper[i] = toGMTFormat(id, i == INDEX_DST_LONG || i == INDEX_DST_SHORT,

                                                i % 2 != 0, locale);

                    break;

                default:

                    break;

                }

            }

            return namesSuper;

        } else {

            // Derive the names for this id. Validate the id first.

            if (Arrays.binarySearch(AVAILABLE_IDS.INSTANCE, id) >= 0) {

                String[] names = new String[INDEX_GEN_SHORT + 1];

                names[INDEX_TZID] = id;

                deriveFallbackNames(names, locale);

                return names;

            }

        }

        return null;

    }

    @Override

    protected String[][] getZoneStrings(Locale locale) {

        // Use English for the ROOT locale

        locale = locale.equals(Locale.ROOT) ? Locale.ENGLISH : locale;

        String[][] ret = super.getZoneStrings(locale);

        // Fill in for the empty names.

        // English names are prefilled for performance.

            for (int zoneIndex = 0; zoneIndex < ret.length; zoneIndex++) {

                deriveFallbackNames(ret[zoneIndex], locale);

            }

        }

        return ret;

    }

    // Derive fallback time zone name according to LDML's logic

    private void deriveFallbackNames(String[] names, Locale locale) {

        for (int i = INDEX_STD_LONG; i <= INDEX_GEN_SHORT; i++) {

            deriveFallbackName(names, i, locale, false);

        }

    }

    private void deriveFallbackName(String[] names, int index, Locale locale, boolean noDST) {

        if (exists(names, index)) {

            return;

        }

        // Check if COMPAT can substitute the name

        if (LocaleProviderAdapter.getAdapterPreference().contains(Type.JRE)) {

            String[] compatNames = (String[])LocaleProviderAdapter.forJRE()

                .getLocaleResources(locale)

                .getTimeZoneNames(names[INDEX_TZID]);

            if (compatNames != null) {

                for (int i = INDEX_STD_LONG; i <= INDEX_GEN_SHORT; i++) {

                    // Assumes COMPAT has no empty slots

                    if (i == index || !exists(names, i)) {

                        names[i] = compatNames[i];

                    }

                }

                return;

            }

        }

        // Type Fallback

        if (noDST && typeFallback(names, index)) {

            return;

        }

        // Region Fallback

        if (regionFormatFallback(names, index, locale)) {

            return;

        }

        // last resort

        String id = names[INDEX_TZID].toUpperCase(Locale.ROOT);

        if (!id.startsWith("UT")) {

            names[index] = toGMTFormat(names[INDEX_TZID],

                                       index == INDEX_DST_LONG || index == INDEX_DST_SHORT,

                                       index % 2 != 0,

                                       locale);

            // aliases of "GMT" timezone.

            if ((exists(names, INDEX_STD_LONG)) && (id.startsWith("Etc/")

                    || id.startsWith("GMT") || id.startsWith("Greenwich"))) {

                switch (id) {

                case "Etc/GMT":

                case "Etc/GMT-0":

                case "Etc/GMT+0":

                case "Etc/GMT0":

                case "GMT+0":

                case "GMT-0":

                case "GMT0":

                case "Greenwich":

                    names[INDEX_DST_LONG] = names[INDEX_GEN_LONG] = names[INDEX_STD_LONG];

                    break;

                }

            }

        }

    }

    private boolean exists(String[] names, int index) {

        return Objects.nonNull(names)

                && Objects.nonNull(names[index])

                && !names[index].isEmpty();

    }

    private boolean typeFallback(String[] names, int index) {

        // check generic

        int genIndex = INDEX_GEN_SHORT - index % 2;

        if (!exists(names, index) && exists(names, genIndex)) {

            names[index] = names[genIndex];

        } else {

            // check standard

            int stdIndex = INDEX_STD_SHORT - index % 2;

            if (!exists(names, index) && exists(names, stdIndex)) {

                names[index] = names[stdIndex];

            }

        }

        return exists(names, index);

    }

    private boolean regionFormatFallback(String[] names, int index, Locale l) {

        String id = names[INDEX_TZID];

        LocaleResources lr = LocaleProviderAdapter.forType(Type.CLDR).getLocaleResources(l);

        ResourceBundle fd = lr.getJavaTimeFormatData();

        String rgn = (String) lr.getTimeZoneNames("timezone.excity." + id);

        if (rgn == null && !id.startsWith("Etc") && !id.startsWith("SystemV")) {

            int slash = id.lastIndexOf('/');

            if (slash > 0) {

                rgn = id.substring(slash + 1).replaceAll("_", " ");

            }

        }

        if (rgn != null) {

            String fmt = "";

            switch (index) {

            case INDEX_STD_LONG:

                fmt = fd.getString("timezone.regionFormat.standard");

                break;

            case INDEX_DST_LONG:

                fmt = fd.getString("timezone.regionFormat.daylight");

                break;

            case INDEX_GEN_LONG:

                fmt = fd.getString("timezone.regionFormat");

                break;

            }

            if (!fmt.isEmpty()) {

                names[index] = MessageFormat.format(fmt, rgn);

            }

        }

        return exists(names, index);

    }

    private String toGMTFormat(String id, boolean daylight, boolean isShort, Locale l) {

        TimeZone tz = ZoneInfoFile.getZoneInfo(id);

        int offset = (tz.getRawOffset() + (daylight ? tz.getDSTSavings() : 0)) / 60000;

        LocaleResources lr = LocaleProviderAdapter.forType(Type.CLDR).getLocaleResources(l);

        ResourceBundle fd = lr.getJavaTimeFormatData();

        if (offset == 0) {

            return fd.getString("timezone.gmtZeroFormat");

        } else {

            String gmtFormat = fd.getString("timezone.gmtFormat");

            String hourFormat = fd.getString("timezone.hourFormat");

            if (offset > 0) {

                hourFormat = hourFormat.substring(0, hourFormat.indexOf(";"));

            } else {

                hourFormat = hourFormat.substring(hourFormat.indexOf(";") + 1);

                offset = -offset;

            }

            hourFormat = hourFormat

                .replaceFirst("H+", (isShort ? "\\%1\\$d" : "\\%1\\$02d"))

                .replaceFirst("m+", "\\%2\\$02d");

            return MessageFormat.format(gmtFormat,

                    String.format(hourFormat, offset / 60, offset % 60));

        }

    }

}