/*

 * Copyright (c) 2012, 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

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

 * questions.

 */

/*

 * Copyright (c) 2009-2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 *

 *  * Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 *

 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

package build.tools.tzdb;

import java.io.ByteArrayOutputStream;

import java.io.DataOutputStream;

import java.nio.charset.StandardCharsets;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.text.ParsePosition;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.Map;

import java.util.NoSuchElementException;

import java.util.Scanner;

import java.util.SortedMap;

import java.util.TreeMap;

import java.util.regex.Matcher;

import java.util.regex.MatchResult;

import java.util.regex.Pattern;

import java.util.stream.Collectors;

/**

 * A compiler that reads a set of TZDB time-zone files and builds a single

 * combined TZDB data file.

 *

 * @since 1.8

 */

public final class TzdbZoneRulesCompiler {

    public static void main(String[] args) {

        new TzdbZoneRulesCompiler().compile(args);

    }

    private void compile(String[] args) {

        if (args.length < 2) {

            outputHelp();

            return;

        }

        Path srcDir = null;

        Path dstFile = null;

        String version = null;

        // parse args/options

        int i;

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

            String arg = args[i];

            if (!arg.startsWith("-")) {

                break;

            }

            if ("-srcdir".equals(arg)) {

                if (srcDir == null && ++i < args.length) {

                    srcDir = Paths.get(args[i]);

                    continue;

                }

            } else if ("-dstfile".equals(arg)) {

                if (dstFile == null && ++i < args.length) {

                    dstFile = Paths.get(args[i]);

                    continue;

                }

            } else if ("-verbose".equals(arg)) {

                if (!verbose) {

                    verbose = true;

                    continue;

                }

            } else if (!"-help".equals(arg)) {

                System.out.println("Unrecognised option: " + arg);

            }

            outputHelp();

            return;

        }

        // check source directory

        if (srcDir == null) {

            System.err.println("Source directory must be specified using -srcdir");

            System.exit(1);

        }

        if (!Files.isDirectory(srcDir)) {

            System.err.println("Source does not exist or is not a directory: " + srcDir);

            System.exit(1);

        }

        // parse source file names

        if (i == args.length) {

            i = 0;

            args = new String[] {"africa", "antarctica", "asia", "australasia", "europe",

                                 "northamerica","southamerica", "backward", "etcetera" };

            System.out.println("Source filenames not specified, using default set ( ");

            for (String name : args) {

                System.out.printf(name + " ");

            }

            System.out.println(")");

        }

        // source files in this directory

        List<Path> srcFiles = new ArrayList<>();

        for (; i < args.length; i++) {

            Path file = srcDir.resolve(args[i]);

            if (Files.exists(file)) {

                srcFiles.add(file);

            } else {

                System.err.println("Source directory does not contain source file: " + args[i]);

                System.exit(1);

            }

        }

        // check destination file

        if (dstFile == null) {

            dstFile = srcDir.resolve("tzdb.dat");

        } else {

            Path parent = dstFile.getParent();

            if (parent != null && !Files.exists(parent)) {

                System.err.println("Destination directory does not exist: " + parent);

                System.exit(1);

            }

        }

        try {

            // get tzdb source version

            Matcher m = Pattern.compile("tzdata(?<ver>[0-9]{4}[A-z])")

                               .matcher(new String(Files.readAllBytes(srcDir.resolve("VERSION")),

                                                   "ISO-8859-1"));

            if (m.find()) {

                version = m.group("ver");

            } else {

                System.exit(1);

                System.err.println("Source directory does not contain file: VERSION");

            }

            // load source files

            printVerbose("Compiling TZDB version " + version);

            TzdbZoneRulesProvider provider = new TzdbZoneRulesProvider(srcFiles);

            // build zone rules

            printVerbose("Building rules");

            // Build the rules, zones and links into real zones.

            SortedMap<String, ZoneRules> builtZones = new TreeMap<>();

            // build zones

            for (String zoneId : provider.getZoneIds()) {

                printVerbose("Building zone " + zoneId);

                builtZones.put(zoneId, provider.getZoneRules(zoneId));

            }

            // build aliases

            Map<String, String> links = provider.getAliasMap();

            for (String aliasId : links.keySet()) {

                String realId = links.get(aliasId);

                printVerbose("Linking alias " + aliasId + " to " + realId);

                ZoneRules realRules = builtZones.get(realId);

                if (realRules == null) {

                    realId = links.get(realId);  // try again (handle alias liked to alias)

                    printVerbose("Relinking alias " + aliasId + " to " + realId);

                    realRules = builtZones.get(realId);

                    if (realRules == null) {

                        throw new IllegalArgumentException("Alias '" + aliasId + "' links to invalid zone '" + realId);

                    }

                    links.put(aliasId, realId);

                }

                builtZones.put(aliasId, realRules);

            }

            // output to file

            printVerbose("Outputting tzdb file: " + dstFile);

            outputFile(dstFile, version, builtZones, links);

        } catch (Exception ex) {

            System.out.println("Failed: " + ex.toString());

            ex.printStackTrace();

            System.exit(1);

        }

        System.exit(0);

    }

    /**

     * Output usage text for the command line.

     */

    private static void outputHelp() {

        System.out.println("Usage: TzdbZoneRulesCompiler <options> <tzdb source filenames>");

        System.out.println("where options include:");

        System.out.println("   -srcdir  <directory>  Where to find tzdb source directory (required)");

        System.out.println("   -dstfile <file>       Where to output generated file (default srcdir/tzdb.dat)");

        System.out.println("   -help                 Print this usage message");

        System.out.println("   -verbose              Output verbose information during compilation");

        System.out.println(" The source directory must contain the unpacked tzdb files, such as asia or europe");

    }

    /**

     * Outputs the file.

     */

    private void outputFile(Path dstFile, String version,

                            SortedMap<String, ZoneRules> builtZones,

                            Map<String, String> links) {

        try (DataOutputStream out = new DataOutputStream(Files.newOutputStream(dstFile))) {

            // file version

            out.writeByte(1);

            // group

            out.writeUTF("TZDB");

            // versions

            out.writeShort(1);

            out.writeUTF(version);

            // regions

            String[] regionArray = builtZones.keySet().toArray(new String[builtZones.size()]);

            out.writeShort(regionArray.length);

            for (String regionId : regionArray) {

                out.writeUTF(regionId);

            }

            // rules  -- remove the dup

            List<ZoneRules> rulesList = builtZones.values().stream()

                .distinct()

                .collect(Collectors.toList());

            out.writeShort(rulesList.size());

            ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);

            for (ZoneRules rules : rulesList) {

                baos.reset();

                DataOutputStream dataos = new DataOutputStream(baos);

                rules.writeExternal(dataos);

                dataos.close();

                byte[] bytes = baos.toByteArray();

                out.writeShort(bytes.length);

                out.write(bytes);

            }

            // link version-region-rules

            out.writeShort(builtZones.size());

            for (Map.Entry<String, ZoneRules> entry : builtZones.entrySet()) {

                 int regionIndex = Arrays.binarySearch(regionArray, entry.getKey());

                 int rulesIndex = rulesList.indexOf(entry.getValue());

                 out.writeShort(regionIndex);

                 out.writeShort(rulesIndex);

            }

            // alias-region

            out.writeShort(links.size());

            for (Map.Entry<String, String> entry : links.entrySet()) {

                 int aliasIndex = Arrays.binarySearch(regionArray, entry.getKey());

                 int regionIndex = Arrays.binarySearch(regionArray, entry.getValue());

                 out.writeShort(aliasIndex);

                 out.writeShort(regionIndex);

            }

            out.flush();

        } catch (Exception ex) {

            System.out.println("Failed: " + ex.toString());

            ex.printStackTrace();

            System.exit(1);

        }

    }

    /** Whether to output verbose messages. */

    private boolean verbose;

    /**

     * private contructor

     */

    private TzdbZoneRulesCompiler() {}

    /**

     * Prints a verbose message.

     *

     * @param message  the message, not null

     */

    private void printVerbose(String message) {

        if (verbose) {

            System.out.println(message);

        }

    }

}