/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  *

  *  http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.any23.mime;

 import java.io.InputStream;

 import java.util.HashMap;

 import java.util.Map;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 /**

  * Basic implementation of {@link MIMETypeDetector} based

  * on file extensions.

  */

 public class NaiveMIMETypeDetector implements MIMETypeDetector {

     private final static Map<String, String> extensions = new HashMap<String, String>() {

         {

             // extension -> mime type

             put("html" , "text/html"            );

             put("htm"  , "text/html"            );

             put("xhtml", "application/xhtml+xml");

             put("xht"  , "application/xhtml+xml");

             put("rdf"  , "application/rdf+xml"  );

             put("xrdf" , "application/rdf+xml"  );

             put("rdfx" , "application/rdf+xml"  );

             put("owl"  , "application/rdf+xml"  );

             put("nt"   , "text/plain"           );

             put("txt"  , "text/plain"           );

             put("ttl"  , "application/x-turtle" );

             put("n3"   , "text/rdf+n3"          );

         }

     };

     private final static Pattern extensionRegex = Pattern.compile(".*\\.([a-z0-9]+)");

     public MIMEType guessMIMEType(

             String fileName,

             InputStream input,

             MIMEType mimeTypeFromMetadata

     ) {

         if (mimeTypeFromMetadata != null) {

             return mimeTypeFromMetadata;

         }

         String extension = getExtension(fileName);

         if (extension == null) {

             // Assume index file on web server.

             extension = "html";

         }

         if (extensions.containsKey(extension)) {

             return MIMEType.parse(extensions.get(extension));

         }

         return null;

     }

     private String getExtension(String filename) {

         Matcher m = extensionRegex.matcher(filename);

         if (!m.matches()) return null;

         return m.group(1);

     }

 }