/*

 * Copyright (c) 2012, 2017, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package build.tools.generatelsrequivmaps;

import java.io.BufferedWriter;

import java.io.IOException;

import java.nio.charset.Charset;

import java.nio.file.Files;

import java.nio.file.Paths;

import java.time.ZoneId;

import java.time.ZonedDateTime;

import java.util.ArrayList;

import java.util.List;

import java.util.Locale;

import java.util.Map;

import java.util.TreeMap;

/**

 * This tool reads the IANA Language Subtag Registry data file downloaded from

 * http://www.iana.org/assignments/language-subtag-registry, which is specified

 * in the command line and generates a .java source file as specified in

 * command line. The generated .java source file contains equivalent language

 * maps. These equivalent language maps are used by LocaleMatcher.java

 * for the locale matching mechanism specified in RFC 4647 "Matching of Language

 * Tags".

 */

public class EquivMapsGenerator {

    public static void main(String[] args) throws Exception {

        if (args.length != 2) {

            System.err.println("Usage: java EquivMapsGenerator"

                    + " language-subtag-registry.txt LocaleEquivalentMaps.java");

            System.exit(1);

        }

        readLSRfile(args[0]);

        generateEquivalentMap();

        generateSourceCode(args[1]);

    }

    private static String LSRrevisionDate;

    private static Map<String, StringBuilder> initialLanguageMap =

        new TreeMap<>();

    private static Map<String, StringBuilder> initialRegionVariantMap =

        new TreeMap<>();

    private static Map<String, String> sortedLanguageMap1 = new TreeMap<>();

    private static Map<String, String[]> sortedLanguageMap2 = new TreeMap<>();

    private static Map<String, String> sortedRegionVariantMap =

        new TreeMap<>();

    private static void readLSRfile(String filename) throws Exception {

        String type = null;

        String tag = null;

        String preferred = null;

        for (String line : Files.readAllLines(Paths.get(filename),

                                              Charset.forName("UTF-8"))) {

            line = line.toLowerCase(Locale.ROOT);

            int index = line.indexOf(' ')+1;

            if (line.startsWith("file-date:")) {

                LSRrevisionDate = line.substring(index);

            } else if (line.startsWith("type:")) {

                type = line.substring(index);

            } else if (line.startsWith("tag:") || line.startsWith("subtag:")) {

                tag = line.substring(index);

            } else if (line.startsWith("preferred-value:")

                       && !type.equals("extlang")) {

                preferred = line.substring(index);

                processDeprecatedData(type, tag, preferred);

            } else if (line.equals("%%")) {

                type = null;

                tag = null;

            }

        }

    }

    private static void processDeprecatedData(String type,

                                              String tag,

                                              String preferred) {

        StringBuilder sb;

        if (type.equals("region") || type.equals("variant")) {

            if (!initialRegionVariantMap.containsKey(preferred)) {

                sb = new StringBuilder("-");

                sb.append(preferred);

                sb.append(",-");

                sb.append(tag);

                initialRegionVariantMap.put("-"+preferred, sb);

            } else {

                throw new RuntimeException("New case, need implementation."

                    + " A region/variant subtag \"" + preferred

                    + "\" is registered for more than one subtags.");

            }

        } else { // language, grandfahered, and redundant

            if (!initialLanguageMap.containsKey(preferred)) {

                sb = new StringBuilder(preferred);

                sb.append(',');

                sb.append(tag);

                initialLanguageMap.put(preferred, sb);

            } else {

                sb = initialLanguageMap.get(preferred);

                sb.append(',');

                sb.append(tag);

                initialLanguageMap.put(preferred, sb);

            }

        }

    }

    private static void generateEquivalentMap() {

        String[] subtags;

        for (String preferred : initialLanguageMap.keySet()) {

            subtags = initialLanguageMap.get(preferred).toString().split(",");

            if (subtags.length == 2) {

                sortedLanguageMap1.put(subtags[0], subtags[1]);

                sortedLanguageMap1.put(subtags[1], subtags[0]);

            } else if (subtags.length > 2) {

                for (int i = 0; i < subtags.length; i++) {

                    sortedLanguageMap2.put(subtags[i], createLangArray(i, subtags));

                }

            } else {

                    throw new RuntimeException("New case, need implementation."

                        + " A language subtag \"" + preferred

                        + "\" is registered for more than two subtags. ");

            }

        }

        for (String preferred : initialRegionVariantMap.keySet()) {

            subtags =

                initialRegionVariantMap.get(preferred).toString().split(",");

            sortedRegionVariantMap.put(subtags[0], subtags[1]);

            sortedRegionVariantMap.put(subtags[1], subtags[0]);

        }

    }

    /* create the array of subtags excluding the subtag at index location */

    private static String[] createLangArray(int index, String[] subtags) {

        List<String> list = new ArrayList<>();

        for (int i = 0; i < subtags.length; i++) {

            if (i != index) {

                list.add(subtags[i]);

            }

        }

        return list.toArray(new String[list.size()]);

    }

    private static String generateValuesString(String[] values) {

        String outputStr = "";

        for (int i = 0; i < values.length; i++) {

            if (i != values.length - 1) {

                outputStr = outputStr + "\"" + values[i] + "\", ";

            } else {

                outputStr = outputStr + "\"" + values[i] + "\"";

            }

        }

        return outputStr;

    }

    private static final String COPYRIGHT = "/*\n"

        + " * Copyright (c) 2012, %d, Oracle and/or its affiliates. All rights reserved.\n"

        + " * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.\n"

        + " *\n"

        + " * This code is free software; you can redistribute it and/or modify it\n"

        + " * under the terms of the GNU General Public License version 2 only, as\n"

        + " * published by the Free Software Foundation.  Oracle designates this\n"

        + " * particular file as subject to the \"Classpath\" exception as provided\n"

        + " * by Oracle in the LICENSE file that accompanied this code.\n"

        + " *\n"

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

        + " * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or\n"

        + " * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License\n"

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

        + " * accompanied this code).\n"

        + " *\n"

        + " * You should have received a copy of the GNU General Public License version\n"

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

        + " * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.\n"

        + " *\n"

        + " * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA\n"

        + " * or visit www.oracle.com if you need additional information or have any\n"

        + " * questions.\n"

        + "*/\n\n";

    private static final String headerText =

        "package sun.util.locale;\n\n"

        + "import java.util.HashMap;\n"

        + "import java.util.Map;\n\n"

        + "final class LocaleEquivalentMaps {\n\n"

        + "    static final Map<String, String> singleEquivMap;\n"

        + "    static final Map<String, String[]> multiEquivsMap;\n"

        + "    static final Map<String, String> regionVariantEquivMap;\n\n"

        + "    static {\n"

        + "        singleEquivMap = new HashMap<>();\n"

        + "        multiEquivsMap = new HashMap<>();\n"

        + "        regionVariantEquivMap = new HashMap<>();\n\n"

        + "        // This is an auto-generated file and should not be manually edited.\n";

    private static final String footerText =

        "    }\n\n"

        + "}";

    private static String getOpenJDKCopyright() {

        int year = ZonedDateTime.now(ZoneId

                .of("America/Los_Angeles")).getYear();

        return String.format(Locale.US, COPYRIGHT, year);

    }

    /**

     * The input lsr data file is in UTF-8, so theoretically for the characters

     * beyond US-ASCII, the generated Java String literals need to be Unicode

     * escaped (\\uXXXX) while writing to a file. But as of now, there is not

     * the case since we don't use "description", "comment" or alike.

     */

    private static void generateSourceCode(String fileName) {

        try (BufferedWriter writer = Files.newBufferedWriter(

                Paths.get(fileName))) {

            writer.write(getOpenJDKCopyright());

            writer.write(headerText

                + "        //   LSR Revision: " + LSRrevisionDate);

            writer.newLine();

            for (String key : sortedLanguageMap1.keySet()) {

                String value = sortedLanguageMap1.get(key);

                writer.write("        singleEquivMap.put(\""

                    + key + "\", \"" + value + "\");");

                writer.newLine();

            }

            writer.newLine();

            for (String key : sortedLanguageMap2.keySet()) {

                String[] values = sortedLanguageMap2.get(key);

                if (values.length >= 2) {

                    writer.write("        multiEquivsMap.put(\""

                        + key + "\", new String[] {"

                        + generateValuesString(values) + "});");

                    writer.newLine();

                }

            }

            writer.newLine();

            for (String key : sortedRegionVariantMap.keySet()) {

                String value = sortedRegionVariantMap.get(key);

                writer.write("        regionVariantEquivMap.put(\""

                    + key + "\", \"" + value + "\");");

                writer.newLine();

            }

            writer.write(footerText);

        } catch (IOException ex) {

            ex.printStackTrace(System.err);

            System.exit(1);

        }

    }

}