package org.daisy.pipeline.braille.tex.impl;
   
   import java.io.InputStream;
   import java.io.IOException;
   import java.net.URI;
   import java.net.URL;
   import java.util.Locale;
   
   import com.google.common.base.MoreObjects;
  import com.google.common.base.MoreObjects.ToStringHelper;
  
  import org.daisy.common.file.URLs;
  import org.daisy.pipeline.braille.common.AbstractHyphenator;
  import org.daisy.pipeline.braille.common.AbstractHyphenator.util.DefaultFullHyphenator;
  import org.daisy.pipeline.braille.common.AbstractTransformProvider;
  import org.daisy.pipeline.braille.common.AbstractTransformProvider.util.Function;
  import org.daisy.pipeline.braille.common.AbstractTransformProvider.util.Iterables;
  import static org.daisy.pipeline.braille.common.AbstractTransformProvider.util.Iterables.fromNullable;
  import static org.daisy.pipeline.braille.common.AbstractTransformProvider.util.Iterables.transform;
  import org.daisy.pipeline.braille.common.HyphenatorProvider;
  import org.daisy.pipeline.braille.common.Query;
  import org.daisy.pipeline.braille.common.Query.MutableQuery;
  import static org.daisy.pipeline.braille.common.Query.util.mutableQuery;
  import static org.daisy.pipeline.braille.common.util.Files.isAbsoluteFile;
  import static org.daisy.pipeline.braille.common.util.Locales.parseLocale;
  import static org.daisy.pipeline.braille.common.util.Strings.extractHyphens;
  import static org.daisy.pipeline.braille.common.util.Tuple2;
  import org.daisy.pipeline.braille.tex.TexHyphenator;
  
  import org.osgi.service.component.annotations.Activate;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Deactivate;
  import org.osgi.service.component.annotations.Reference;
  import org.osgi.service.component.annotations.ReferenceCardinality;
  import org.osgi.service.component.annotations.ReferencePolicy;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  @Component(
  	name = "org.daisy.pipeline.braille.tex.impl.TexHyphenatorSimpleImpl",
  	service = {
  		TexHyphenator.Provider.class,
  		HyphenatorProvider.class
  	}
  )
  public class TexHyphenatorSimpleImpl extends AbstractTransformProvider<TexHyphenator>
  	                                 implements TexHyphenator.Provider {
  	
  	private TexHyphenatorTableRegistry tableRegistry;
  	
  	@Activate
  	protected void activate() {
  		logger.debug("Loading TeX hyphenation service");
  	}
  	
  	@Deactivate
  	protected void deactivate() {
  		logger.debug("Unloading TeX hyphenation service");
  	}
  	
  	@Reference(
  		name = "TexHyphenatorTableRegistry",
  		unbind = "-",
  		service = TexHyphenatorTableRegistry.class,
  		cardinality = ReferenceCardinality.MANDATORY,
  		policy = ReferencePolicy.STATIC
  	)
  	protected void bindTableRegistry(TexHyphenatorTableRegistry registry) {
  		tableRegistry = registry;
  		logger.debug("Registering Tex hyphenation table registry: " + registry);
  	}
  	
  	protected void unbindTableRegistry(TexHyphenatorTableRegistry registry) {
  		tableRegistry = null;
  	}
  	
  	private final static Iterable<TexHyphenator> empty = Iterables.<TexHyphenator>empty();
  	
  	public Iterable<TexHyphenator> _get(Query query) {
  		MutableQuery q = mutableQuery(query);
  		if (q.containsKey("hyphenator")) {
  			String v = q.removeOnly("hyphenator").getValue().get();
  			if (!"texhyph".equals(v) && !"tex".equals(v))
  				return fromNullable(fromId(v)); }
  		if (q.containsKey("table")) {
  			String v = q.removeOnly("table").getValue().get();
  			if (!q.isEmpty()) {
  				logger.warn("A query with both 'table' and '" + q.iterator().next().getKey() + "' never matches anything");
  				return empty; }
  			return fromNullable(get(URLs.asURI(v))); }
  		Locale locale; {
  			String loc;
  			if (q.containsKey("document-locale"))
  				loc = q.removeOnly("document-locale").getValue().get();
  			else
  				loc = "und";
  			try {
  				locale = parseLocale(loc); }
 			catch (IllegalArgumentException e) {
 				logger.error("Invalid locale", e);
 				return empty; }
 		}
 		if (!q.isEmpty()) {
 			logger.warn("A query with '" + q.iterator().next().getKey() + "' never matches anything");
 			return empty; }
 		if (tableRegistry != null) {
 			return transform(
 				tableRegistry.get(locale),
 				new Function<URI,TexHyphenator>() {
 					public TexHyphenator _apply(URI table) {
 						return get(table); }}); }
 		return empty;
 	}
 	
 	private TexHyphenator get(URI table) {
 		if (table.toString().endsWith(".tex")) {
 			try { return new TexHyphenatorImpl(table); }
 			catch (Exception e) {
 				logger.warn("Could not create hyphenator for table " + table, e); }}
 		return null;
 	}
 	
 	private class TexHyphenatorImpl extends AbstractHyphenator implements TexHyphenator {
 		
 		private final URI table;
 		private final net.davidashen.text.Hyphenator hyphenator;
 		
 		private TexHyphenatorImpl(URI table) throws IOException {
 			this.table = table;
 			hyphenator = new net.davidashen.text.Hyphenator();
 			InputStream stream = resolveTable(table).openStream();
 			hyphenator.loadTable(stream);
 			stream.close();
 		}
 		
 		public URI asTexHyphenatorTable() {
 			return table;
 		}
 		
 		@Override
 		public FullHyphenator asFullHyphenator() {
 			return fullHyphenator;
 		}
 		
 		private final FullHyphenator fullHyphenator = new DefaultFullHyphenator() {
 
 				private final static char SHY = '\u00AD';
 				private final static char ZWSP = '\u200B';
 
 				protected boolean isCodePointAware() { return true; }
 				protected boolean isLanguageAdaptive() { return true; }
 		
 				/**
 				 * @param language ignored
 				 */
 				protected byte[] getHyphenationOpportunities(String textWithoutHyphens, Locale language) throws RuntimeException {
 					try {
 						Tuple2<String,byte[]> t = extractHyphens(
 							hyphenator.hyphenate(textWithoutHyphens), true, SHY, ZWSP);
 						if (!t._1.equals(textWithoutHyphens))
 							throw new RuntimeException("Unexpected output from " + hyphenator);
 						return t._2; }
 					catch (Exception e) {
 						throw new RuntimeException("Error during TeX hyphenation", e); }
 				}
 			};
 	}
 	
 	private URL resolveTable(URI table) {
 		URL resolvedTable = isAbsoluteFile(table) ? URLs.asURL(table) : tableRegistry.resolve(table);
 		if (resolvedTable == null)
 			throw new RuntimeException("Hyphenation table " + table + " could not be resolved");
 		return resolvedTable;
 	}
 	
 	@Override
 	public ToStringHelper toStringHelper() {
 		return MoreObjects.toStringHelper("TexHyphenatorSimpleImpl");
 	}
 	
 	private static final Logger logger = LoggerFactory.getLogger(TexHyphenatorSimpleImpl.class);
 	
 }