filebot/source/net/filebot/media/ReleaseInfo.java

package net.filebot.media;

import static java.lang.Integer.*;
import static java.nio.charset.StandardCharsets.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;
import static java.util.ResourceBundle.*;
import static java.util.regex.Pattern.*;
import static net.filebot.similarity.Normalization.*;
import static net.filebot.util.FileUtilities.*;
import static net.filebot.util.StringUtilities.*;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.text.Collator;
import java.text.Normalizer;
import java.text.Normalizer.Form;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.TreeMap;
import java.util.function.Function;
import java.util.function.IntFunction;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.filebot.Cache;
import net.filebot.CacheType;
import net.filebot.Resource;
import net.filebot.util.ByteBufferInputStream;
import net.filebot.util.FileUtilities.RegexFileFilter;
import net.filebot.web.AnidbSearchResult;
import net.filebot.web.CachedResource;
import net.filebot.web.Movie;
import net.filebot.web.SubtitleSearchResult;
import net.filebot.web.TheTVDBSearchResult;

import org.tukaani.xz.XZInputStream;

public class ReleaseInfo {

	private String[] videoSources;
	private Pattern videoSourcePattern;

	public String getVideoSource(String... input) {
		if (videoSources == null || videoSourcePattern == null) {
			videoSources = PIPE.split(getProperty("pattern.video.source"));
			videoSourcePattern = getVideoSourcePattern();
		}

		// check parent and itself for group names
		return matchLast(videoSourcePattern, videoSources, input);
	}

	private Pattern videoTagPattern;

	public List<String> getVideoTags(String... input) {
		if (videoTagPattern == null) {
			videoTagPattern = getVideoTagPattern();
		}

		List<String> tags = new ArrayList<String>();
		for (String s : input) {
			if (s == null)
				continue;

			Matcher m = videoTagPattern.matcher(s);
			while (m.find()) {
				tags.add(m.group());
			}
		}
		return tags;
	}

	public String getStereoscopic3D(String... input) {
		Pattern pattern = getStereoscopic3DPattern();
		for (String s : input) {
			Matcher m = pattern.matcher(s);
			if (m.find()) {
				return m.group();
			}
		}
		return null;
	}

	public String getReleaseGroup(String... strings) throws Exception {
		// check file and folder for release group names
		String[] groups = releaseGroup.get();

		// try case-sensitive match
		String match = matchLast(getReleaseGroupPattern(true), groups, strings);

		// try case-insensitive match as fallback
		if (match == null) {
			match = matchLast(getReleaseGroupPattern(false), groups, strings);
		}

		return match;
	}

	private Map<String, Locale> languages;
	private Pattern languageSuffix;

	public Locale getLanguageSuffix(String name) {
		// match locale identifier and lookup Locale object
		if (languages == null || languageSuffix == null) {
			languages = getLanguageMap(Locale.ENGLISH, Locale.getDefault());
			languageSuffix = getLanguageSuffixPattern(languages.keySet(), false);
		}

		String lang = matchLast(languageSuffix, null, name);
		if (lang == null)
			return null;

		return languages.get(lang);
	}

	protected String matchLast(Pattern pattern, String[] standardValues, CharSequence... sequence) {
		String lastMatch = null;

		// match last occurrence
		for (CharSequence name : sequence) {
			if (name == null)
				continue;

			Matcher matcher = pattern.matcher(name);
			while (matcher.find()) {
				lastMatch = matcher.group();
			}
		}

		// prefer standard value over matched value
		if (lastMatch != null && standardValues != null) {
			for (String standard : standardValues) {
				if (standard.equalsIgnoreCase(lastMatch)) {
					return standard;
				}
			}
		}

		return lastMatch;
	}

	// cached patterns
	private final Map<Boolean, Pattern[]> stopwords = new HashMap<Boolean, Pattern[]>(2);
	private final Map<Boolean, Pattern[]> blacklist = new HashMap<Boolean, Pattern[]>(2);

	public List<String> cleanRelease(Collection<String> items, boolean strict) throws Exception {
		Pattern[] stopwords;
		Pattern[] blacklist;

		// initialize cached patterns
		synchronized (this.stopwords) {
			stopwords = this.stopwords.get(strict);
			blacklist = this.blacklist.get(strict);

			if (stopwords == null || blacklist == null) {
				Set<String> languages = getLanguageMap(Locale.ENGLISH, Locale.getDefault()).keySet();
				Pattern clutterBracket = getClutterBracketPattern(strict);
				Pattern releaseGroup = getReleaseGroupPattern(strict);
				Pattern languageSuffix = getLanguageSuffixPattern(languages, strict);
				Pattern languageTag = getLanguageTagPattern(languages);
				Pattern videoSource = getVideoSourcePattern();
				Pattern videoTags = getVideoTagPattern();
				Pattern videoFormat = getVideoFormatPattern(strict);
				Pattern stereoscopic3d = getStereoscopic3DPattern();
				Pattern resolution = getResolutionPattern();
				Pattern queryBlacklist = getBlacklistPattern();

				stopwords = new Pattern[] { languageTag, videoSource, videoTags, videoFormat, resolution, stereoscopic3d, languageSuffix };
				blacklist = new Pattern[] { queryBlacklist, languageTag, clutterBracket, releaseGroup, videoSource, videoTags, videoFormat, resolution, stereoscopic3d, languageSuffix };

				// cache compiled patterns for common usage
				this.stopwords.put(strict, stopwords);
				this.blacklist.put(strict, blacklist);
			}
		}

		List<String> output = new ArrayList<String>(items.size());
		for (String it : items) {
			it = strict ? clean(it, stopwords) : substringBefore(it, stopwords);
			it = normalizePunctuation(clean(it, blacklist));

			// ignore empty values
			if (it.length() > 0) {
				output.add(it);
			}
		}

		return output;
	}

	public String clean(String item, Pattern... blacklisted) {
		for (Pattern it : blacklisted) {
			item = it.matcher(item).replaceAll("");
		}
		return item;
	}

	public String substringBefore(String item, Pattern... stopwords) {
		for (Pattern it : stopwords) {
			Matcher matcher = it.matcher(item);
			if (matcher.find()) {
				String substring = item.substring(0, matcher.start()); // use substring before the matched stopword
				if (normalizePunctuation(substring).length() >= 3) {
					item = substring; // make sure that the substring has enough data
				}
			}
		}
		return item;
	}

	// cached patterns
	private Set<File> volumeRoots;
	private Pattern structureRootFolderPattern;

	public Set<File> getVolumeRoots() {
		if (volumeRoots == null) {
			Set<File> volumes = new HashSet<File>();

			// user root folder
			volumes.add(new File(System.getProperty("user.home")));

			// Windows / Linux / Mac system roots
			volumes.addAll(getFileSystemRoots());

			if (File.separator.equals("/")) {
				// Linux and Mac system root folders
				for (File root : getFileSystemRoots()) {
					volumes.addAll(getChildren(root, FOLDERS));
				}

				// user-specific media roots
				for (File mediaRoot : getMediaRoots()) {
					volumes.addAll(getChildren(mediaRoot, FOLDERS));
					volumes.add(mediaRoot);

					// add additional user roots if user.home is not set properly or listFiles doesn't work
					String username = System.getProperty("user.name");
					if (username != null && username.length() > 0) {
						volumes.add(new File(mediaRoot, username));
					}
				}
			}

			volumeRoots = unmodifiableSet(volumes);
		}
		return volumeRoots;
	}

	public Pattern getStructureRootPattern() throws Exception {
		if (structureRootFolderPattern == null) {
			List<String> folders = new ArrayList<String>();
			for (String it : queryBlacklist.get()) {
				if (it.startsWith("^") && it.endsWith("$")) {
					folders.add(it);
				}
			}
			structureRootFolderPattern = compile(or(folders.toArray()), CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS);
		}
		return structureRootFolderPattern;
	}

	public Pattern getLanguageTagPattern(Collection<String> languages) {
		// [en]
		return compile("(?<=[-\\[{(])" + or(quoteAll(languages)) + "(?=\\p{Punct})", CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS);
	}

	public Pattern getLanguageSuffixPattern(Collection<String> languages, boolean strict) {
		// e.g. ".en.srt" or ".en.forced.srt"
		return compile("(?<=[._-])" + or(quoteAll(languages)) + "(?=([._-](" + getProperty("pattern.subtitle.tags") + "))?$)", strict ? 0 : CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS);
	}

	public Pattern getResolutionPattern() {
		// match screen resolutions 640x480, 1280x720, etc
		return compile("(?<!\\p{Alnum})(\\d{4}|[6-9]\\d{2})x(\\d{4}|[4-9]\\d{2})(?!\\p{Alnum})");
	}

	public Pattern getVideoFormatPattern(boolean strict) {
		// pattern matching any video source name
		String pattern = getProperty("pattern.video.format");
		return strict ? compile("(?<!\\p{Alnum})(" + pattern + ")(?!\\p{Alnum})", CASE_INSENSITIVE) : compile(pattern, CASE_INSENSITIVE);
	}

	public Pattern getVideoSourcePattern() {
		// pattern matching any video source name, like BluRay
		String pattern = getProperty("pattern.video.source");
		return compile("(?<!\\p{Alnum})(" + pattern + ")(?!\\p{Alnum})", CASE_INSENSITIVE);
	}

	public Pattern getVideoTagPattern() {
		// pattern matching any video tag, like Directors Cut
		String pattern = getProperty("pattern.video.tags");
		return compile("(?<!\\p{Alnum})(" + pattern + ")(?!\\p{Alnum})", CASE_INSENSITIVE);
	}

	public Pattern getStereoscopic3DPattern() {
		// pattern matching any 3D flags like 3D.HSBS
		String pattern = getProperty("pattern.video.s3d");
		return compile("(?<!\\p{Alnum})(" + pattern + ")(?!\\p{Alnum})", CASE_INSENSITIVE);
	}

	public Pattern getClutterBracketPattern(boolean strict) {
		// match patterns like [Action, Drama] or {ENG-XViD-MP3-DVDRiP} etc
		String contentFilter = strict ? "[\\p{Space}\\p{Punct}&&[^\\[\\]]]" : "\\p{Alpha}";
		return compile("(?:\\[([^\\[\\]]+?" + contentFilter + "[^\\[\\]]+?)\\])|(?:\\{([^\\{\\}]+?" + contentFilter + "[^\\{\\}]+?)\\})|(?:\\(([^\\(\\)]+?" + contentFilter + "[^\\(\\)]+?)\\))");
	}

	public Pattern getReleaseGroupPattern(boolean strict) throws Exception {
		// pattern matching any release group name enclosed in separators
		return compile("(?<!\\p{Alnum})" + or(releaseGroup.get()) + "(?!\\p{Alnum}|[^\\p{Alnum}](19|20)\\d{2})", strict ? 0 : CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS);
	}

	public Pattern getBlacklistPattern() throws Exception {
		// pattern matching any release group name enclosed in separators
		return compile("(?<!\\p{Alnum})" + or(queryBlacklist.get()) + "(?!\\p{Alnum})", CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS);
	}

	public Pattern getExcludePattern() throws Exception {
		// pattern matching any release group name enclosed in separators
		return compile(or(excludeBlacklist.get()), CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS);
	}

	public Pattern getCustomRemovePattern(Collection<String> terms) throws IOException {
		return compile("(?<!\\p{Alnum})" + or(quoteAll(terms)) + "(?!\\p{Alnum})", CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS);
	}

	public Movie[] getMovieList() throws Exception {
		return movieIndex.get();
	}

	public TheTVDBSearchResult[] getTheTVDBIndex() throws Exception {
		return tvdbIndex.get();
	}

	public AnidbSearchResult[] getAnidbIndex() throws Exception {
		return anidbIndex.get();
	}

	public SubtitleSearchResult[] getOpenSubtitlesIndex() throws Exception {
		return osdbIndex.get();
	}

	private Map<Pattern, String> seriesDirectMappings;

	public Map<Pattern, String> getSeriesDirectMappings() throws Exception {
		if (seriesDirectMappings == null) {
			Map<Pattern, String> mappings = new LinkedHashMap<Pattern, String>();
			for (String line : seriesDirectMappingsResource.get()) {
				String[] tsv = line.split("\t", 2);
				if (tsv.length == 2) {
					mappings.put(compile("(?<!\\p{Alnum})(" + tsv[0] + ")(?!\\p{Alnum})", CASE_INSENSITIVE | UNICODE_CHARACTER_CLASS), tsv[1]);
				}
			}
			seriesDirectMappings = unmodifiableMap(mappings);
		}
		return seriesDirectMappings;
	}

	private static FolderEntryFilter diskFolderFilter;

	public FileFilter getDiskFolderFilter() {
		if (diskFolderFilter == null) {
			diskFolderFilter = new FolderEntryFilter(compile(getProperty("pattern.diskfolder.entry")));
		}
		return diskFolderFilter;
	}

	private static RegexFileFilter diskFolderEntryFilter;

	public FileFilter getDiskFolderEntryFilter() {
		if (diskFolderEntryFilter == null) {
			diskFolderEntryFilter = new RegexFileFilter(compile(getProperty("pattern.diskfolder.entry")));
		}
		return diskFolderEntryFilter;
	}

	private static ClutterFileFilter clutterFileFilter;

	public FileFilter getClutterFileFilter() throws Exception {
		if (clutterFileFilter == null) {
			clutterFileFilter = new ClutterFileFilter(getExcludePattern(), Long.parseLong(getProperty("number.clutter.maxfilesize"))); // only files smaller than 250 MB may be considered clutter
		}
		return clutterFileFilter;
	}

	public List<File> getMediaRoots() {
		List<File> roots = new ArrayList<File>();
		for (String it : getProperty("folder.media.roots").split(":")) {
			roots.add(new File(it));
		}
		return roots;
	}

	// fetch release group names online and try to update the data every other day

	protected final Resource<String[]> releaseGroup = patternResource("url.release-groups");
	protected final Resource<String[]> queryBlacklist = patternResource("url.query-blacklist");
	protected final Resource<String[]> excludeBlacklist = patternResource("url.exclude-blacklist");
	protected final Resource<String[]> seriesDirectMappingsResource = patternResource("url.series-mappings");

	protected final Resource<Movie[]> movieIndex = tsvResource("url.movie-list", this::parseMovie, Movie[]::new);
	protected final Resource<TheTVDBSearchResult[]> tvdbIndex = tsvResource("url.thetvdb-index", this::parseSeries, TheTVDBSearchResult[]::new);
	protected final Resource<AnidbSearchResult[]> anidbIndex = tsvResource("url.anidb-index", this::parseAnime, AnidbSearchResult[]::new);
	protected final Resource<SubtitleSearchResult[]> osdbIndex = tsvResource("url.osdb-index", this::parseSubtitle, SubtitleSearchResult[]::new);

	private Movie parseMovie(String[] v) {
		int imdbid = parseInt(v[0]);
		int tmdbid = parseInt(v[1]);
		int year = parseInt(v[2]);
		String name = v[3];
		String[] aliasNames = copyOfRange(v, 4, v.length);
		return new Movie(name, aliasNames, year, imdbid > 0 ? imdbid : -1, tmdbid > 0 ? tmdbid : -1, null);
	}

	private TheTVDBSearchResult parseSeries(String[] v) {
		int id = parseInt(v[0]);
		String name = v[1];
		String[] aliasNames = copyOfRange(v, 2, v.length);
		return new TheTVDBSearchResult(name, aliasNames, id);
	}

	private AnidbSearchResult parseAnime(String[] v) {
		int aid = parseInt(v[0]);
		String primaryTitle = v[1];
		String[] aliasNames = copyOfRange(v, 2, v.length);
		return new AnidbSearchResult(aid, primaryTitle, aliasNames);
	}

	private SubtitleSearchResult parseSubtitle(String[] v) {
		String kind = v[0];
		int score = parseInt(v[1]);
		int imdbId = parseInt(v[2]);
		int year = parseInt(v[3]);
		String name = v[4];
		String[] aliasNames = copyOfRange(v, 5, v.length);
		return new SubtitleSearchResult(name, aliasNames, year, imdbId, -1, Locale.ENGLISH, SubtitleSearchResult.Kind.forName(kind), score);
	}

	protected Resource<String[]> patternResource(String name) {
		return resource(name, Cache.ONE_WEEK, s -> {
			return s.length() > 0 ? s : null;
		}, String[]::new);
	}

	protected <T> Resource<T[]> tsvResource(String name, Function<String[], T> parse, IntFunction<T[]> generator) {
		return resource(name, Cache.ONE_WEEK, s -> {
			String[] v = s.split("\t");
			return v.length > 0 ? parse.apply(v) : null;
		}, generator);
	}

	protected <T> Resource<T[]> resource(String name, Duration expirationTime, Function<String, T> parse, IntFunction<T[]> generator) {
		return () -> {
			Cache cache = Cache.getCache("data", CacheType.Persistent);
			byte[] bytes = cache.bytes(name, n -> new URL(getProperty(n))).expire(expirationTime).get();

			// all data file are xz compressed
			try (BufferedReader text = new BufferedReader(new InputStreamReader(new XZInputStream(new ByteArrayInputStream(bytes)), UTF_8))) {
				return text.lines().map(parse).filter(Objects::nonNull).toArray(generator);
			}
		};
	}

	protected String getProperty(String name) {
		// override resource locations via Java System properties
		return System.getProperty(name, getBundle(ReleaseInfo.class.getName()).getString(name));
	}

	protected static class PatternResource extends CachedResource<String[]> {

		public PatternResource(String resource) {
			super(resource, String[].class, ONE_WEEK); // check for updates every week
		}

		@Override
		public String[] process(ByteBuffer data) {
			return compile("\\n").split(Charset.forName("UTF-8").decode(data));
		}
	}

	protected static class MovieResource extends CachedResource<Movie[]> {

		public MovieResource(String resource) {
			super(resource, Movie[].class, ONE_MONTH); // check for updates every month
		}

		@Override
		public Movie[] process(ByteBuffer data) throws IOException {
			List<String[]> rows = readCSV(new XZInputStream(new ByteBufferInputStream(data)), "UTF-8", "\t");
			List<Movie> movies = new ArrayList<Movie>(rows.size());

			for (String[] row : rows) {
				int imdbid = parseInt(row[0]);
				int tmdbid = parseInt(row[1]);
				int year = parseInt(row[2]);
				String name = row[3];
				String[] aliasNames = copyOfRange(row, 4, row.length);
				movies.add(new Movie(name, aliasNames, year, imdbid > 0 ? imdbid : -1, tmdbid > 0 ? tmdbid : -1, null));
			}

			return movies.toArray(new Movie[0]);
		}
	}

	protected static class TheTVDBIndexResource extends CachedResource<TheTVDBSearchResult[]> {

		public TheTVDBIndexResource(String resource) {
			super(resource, TheTVDBSearchResult[].class, ONE_WEEK); // check for updates every week
		}

		@Override
		public TheTVDBSearchResult[] process(ByteBuffer data) throws IOException {
			List<String[]> rows = readCSV(new XZInputStream(new ByteBufferInputStream(data)), "UTF-8", "\t");
			List<TheTVDBSearchResult> tvshows = new ArrayList<TheTVDBSearchResult>(rows.size());

			for (String[] row : rows) {
				int id = parseInt(row[0]);
				String name = row[1];
				String[] aliasNames = copyOfRange(row, 2, row.length);
				tvshows.add(new TheTVDBSearchResult(name, aliasNames, id));
			}

			return tvshows.toArray(new TheTVDBSearchResult[0]);
		}
	}

	protected static class AnidbIndexResource extends CachedResource<AnidbSearchResult[]> {

		public AnidbIndexResource(String resource) {
			super(resource, AnidbSearchResult[].class, ONE_WEEK); // check for updates every week
		}

		@Override
		public AnidbSearchResult[] process(ByteBuffer data) throws IOException {
			List<String[]> rows = readCSV(new XZInputStream(new ByteBufferInputStream(data)), "UTF-8", "\t");
			List<AnidbSearchResult> anime = new ArrayList<AnidbSearchResult>(rows.size());

			for (String[] row : rows) {
				int aid = parseInt(row[0]);
				String primaryTitle = row[1];
				String[] aliasNames = copyOfRange(row, 2, row.length);
				anime.add(new AnidbSearchResult(aid, primaryTitle, aliasNames));
			}

			return anime.toArray(new AnidbSearchResult[0]);
		}
	}

	protected static class OpenSubtitlesIndexResource extends CachedResource<SubtitleSearchResult[]> {

		public OpenSubtitlesIndexResource(String resource) {
			super(resource, SubtitleSearchResult[].class, ONE_MONTH); // check for updates every month
		}

		@Override
		public SubtitleSearchResult[] process(ByteBuffer data) throws IOException {
			List<String[]> rows = readCSV(new XZInputStream(new ByteBufferInputStream(data)), "UTF-8", "\t");
			List<SubtitleSearchResult> result = new ArrayList<SubtitleSearchResult>(rows.size());

			for (String[] row : rows) {
				String kind = row[0];
				int score = parseInt(row[1]);
				int imdbId = parseInt(row[2]);
				int year = parseInt(row[3]);
				String name = row[4];
				String[] aliasNames = copyOfRange(row, 5, row.length);
				result.add(new SubtitleSearchResult(name, aliasNames, year, imdbId, -1, Locale.ENGLISH, SubtitleSearchResult.Kind.forName(kind), score));
			}

			return result.toArray(new SubtitleSearchResult[0]);
		}
	}

	protected static class FolderEntryFilter implements FileFilter {

		private final Pattern entryPattern;

		public FolderEntryFilter(Pattern entryPattern) {
			this.entryPattern = entryPattern;
		}

		@Override
		public boolean accept(File dir) {
			if (dir.isDirectory()) {
				for (File f : getChildren(dir)) {
					if (entryPattern.matcher(f.getName()).matches()) {
						return true;
					}
				}
			}
			return false;
		}
	}

	public static class FileFolderNameFilter implements FileFilter {

		private final Pattern namePattern;

		public FileFolderNameFilter(Pattern namePattern) {
			this.namePattern = namePattern;
		}

		@Override
		public boolean accept(File file) {
			return (namePattern.matcher(file.getName()).find() || (file.isFile() && namePattern.matcher(file.getParentFile().getName()).find()));
		}
	}

	public static class ClutterFileFilter extends FileFolderNameFilter {

		private long maxFileSize;

		public ClutterFileFilter(Pattern namePattern, long maxFileSize) {
			super(namePattern);
			this.maxFileSize = maxFileSize;
		}

		@Override
		public boolean accept(File file) {
			return super.accept(file) && file.isFile() && file.length() < maxFileSize;
		}
	}

	private String or(Object[] terms) {
		return joinSorted(terms, "|", reverseOrder(), "(", ")"); // non-capturing group that matches the longest occurrence
	}

	private String[] quoteAll(Collection<String> values) {
		return values.stream().map((s) -> Pattern.quote(s)).toArray(String[]::new);
	}

	public Map<String, Locale> getLanguageMap(Locale... supportedDisplayLocale) {
		// use maximum strength collator by default
		Collator collator = Collator.getInstance(Locale.ENGLISH);
		collator.setDecomposition(Collator.FULL_DECOMPOSITION);
		collator.setStrength(Collator.PRIMARY);

		Comparator<? super String> order = collator;
		Map<String, Locale> languageMap = new TreeMap<String, Locale>(order);

		for (String code : Locale.getISOLanguages()) {
			Locale locale = new Locale(code); // force ISO3 language as default toString() value
			Locale iso3locale = new Locale(locale.getISO3Language());

			languageMap.put(locale.getLanguage(), iso3locale);
			languageMap.put(locale.getISO3Language(), iso3locale);

			// map display language names for given locales
			for (Locale language : new HashSet<Locale>(asList(supportedDisplayLocale))) {
				// make sure language name is properly normalized so accents and whatever don't break the regex pattern syntax
				String languageName = Normalizer.normalize(locale.getDisplayLanguage(language), Form.NFKD);
				languageMap.put(languageName.toLowerCase(), iso3locale);
			}
		}

		// unofficial language for pb/pob for Portuguese (Brazil)
		Locale brazil = new Locale("pob");
		languageMap.put("brazilian", brazil);
		languageMap.put("pb", brazil);
		languageMap.put("pob", brazil);

		// missing ISO 639-2 (B/T) locales (see https://github.com/TakahikoKawasaki/nv-i18n/blob/master/src/main/java/com/neovisionaries/i18n/LanguageAlpha3Code.java)
		languageMap.put("tib", new Locale("bod"));
		languageMap.put("cze", new Locale("ces"));
		languageMap.put("wel", new Locale("cym"));
		languageMap.put("ger", new Locale("deu"));
		languageMap.put("gre", new Locale("ell"));
		languageMap.put("baq", new Locale("eus"));
		languageMap.put("per", new Locale("fas"));
		languageMap.put("fre", new Locale("fra"));
		languageMap.put("arm", new Locale("hye"));
		languageMap.put("ice", new Locale("isl"));
		languageMap.put("geo", new Locale("kat"));
		languageMap.put("mac", new Locale("mkd"));
		languageMap.put("mao", new Locale("mri"));
		languageMap.put("may", new Locale("msa"));
		languageMap.put("bur", new Locale("mya"));
		languageMap.put("dut", new Locale("nld"));
		languageMap.put("rum", new Locale("ron"));
		languageMap.put("slo", new Locale("slk"));
		languageMap.put("alb", new Locale("sqi"));
		languageMap.put("chi", new Locale("zho"));

		// remove illegal tokens
		languageMap.remove("");
		languageMap.remove("II");
		languageMap.remove("III");
		languageMap.remove("hi"); // hi => typically used for hearing-impaired subtitles, NOT hindi language

		return unmodifiableMap(languageMap);
	}

}