/*
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.activation;

import java.io.*;
import com.sun.activation.registries.MimeTypeFile;

/**
 * This class extends FileTypeMap and provides data typing of files
 * via their file extension. It uses the <code>.mime.types</code> format. <p>
 *
 * <b>MIME types file search order:</b><p>
 * The MimetypesFileTypeMap looks in various places in the user's
 * system for MIME types file entries. When requests are made
 * to search for MIME types in the MimetypesFileTypeMap, it searches  
 * MIME types files in the following order:
 * <p>
 * <ol>
 * <li> Programmatically added entries to the MimetypesFileTypeMap instance.
 * <li> The file <code>.mime.types</code> in the user's home directory.
 * <li> The file <<i>java.home</i>><code>/lib/mime.types</code>.
 * <li> The file or resource named <code>META-INF/mime.types</code>.
 * <li> The file or resource named <code>META-INF/mimetypes.default</code>
 * (usually found only in the <code>activation.jar</code> file).
 * </ol>
 * <p>
 * <b>MIME types file format:</b><p>
 *
 * <code>
 * # comments begin with a '#'<br>
 * # the format is <mime type> <space separated file extensions><br>
 * # for example:<br>
 * text/plain    txt text TXT<br>
 * # this would map file.txt, file.text, and file.TXT to<br>
 * # the mime type "text/plain"<br>
 * </code>
 *
 * @author Bart Calder
 * @author Bill Shannon
 */
public class MimetypesFileTypeMap extends FileTypeMap {
    /*
     * We manage up to 5 databases, searched in order.
     * The default database is shared between all instances
     * of this class.
     * XXX - Can we safely share more databases between instances?
     */
    private static MimeTypeFile defDB = null;
    private MimeTypeFile[] DB = new MimeTypeFile[5];
    private static final int PROG = 0;	// programmatically added entries
    private static final int HOME = 1;	// the user's home directory
    private static final int SYS = 2;	// the system file
    private static final int JAR = 3;	// the app's entry in the jar file
    private static final int DEF = 4;	// the default entry in our jar file

    private static String defaultType = "application/octet-stream";

    /**
     * The default constructor.
     */
    public MimetypesFileTypeMap() {
	try {
	    String user_home = System.getProperty("user.home");

	    if (user_home != null) {
		String path = user_home + File.separator + ".mime.types";
		DB[HOME] = loadFile(path);
	    }
	} catch (SecurityException ex) {}

	try {
	    // check system's home
	    String system_mimetypes = System.getProperty("java.home") +
		File.separator + "lib" + File.separator + "mime.types";
	    DB[SYS] = loadFile(system_mimetypes);
	} catch (SecurityException ex) {}

	// load from the app's jar file
	DB[JAR] = loadResource("/META-INF/mime.types");

	synchronized (MimetypesFileTypeMap.class) {
	    // see if another instance has created this yet.
	    if (defDB == null)
		defDB = loadResource("/META-INF/mimetypes.default");
	}

	DB[DEF] = defDB;
    }

    /**
     * Load the named resource.
     */
    private MimeTypeFile loadResource(String name) {
	try {
	    InputStream clis = this.getClass().getResourceAsStream(name);
	    if (clis != null)
		return new MimeTypeFile(clis);
	} catch (IOException e) {
	    // e.printStackTrace();
	}
	return null;
    }

    /**
     * Load the named file.
     */
    private MimeTypeFile loadFile(String name) {
	MimeTypeFile mtf = null;

	try {
	    mtf = new MimeTypeFile(name);
	} catch (IOException e) {
	    //	e.printStackTrace();
	}
	return mtf;
    }

    /**
     * Construct a MimetypesFileTypeMap with programmatic entries
     * added from the named file.
     *
     * @param mimeTypeFileName	the file name
     */
    public MimetypesFileTypeMap(String mimeTypeFileName) throws IOException {
	this();
	DB[PROG] = new MimeTypeFile(mimeTypeFileName);
    }

    /**
     * Construct a MimetypesFileTypeMap with programmatic entries
     * added from the InputStream.
     *
     * @param is	the input stream to read from
     */
    public MimetypesFileTypeMap(InputStream is) {
	this();
	try {
	    DB[PROG] = new MimeTypeFile(is);
	} catch (IOException ex) {
	    // XXX - really should throw it
	}
    }

    /**
     * Prepend the MIME type values to the registry.
     *
     * @param mime_types A .mime.types formatted string of entries.
     */
    public synchronized void addMimeTypes(String mime_types) {
	// check to see if we have created the registry
	if (DB[PROG] == null)
	    DB[PROG] = new MimeTypeFile(); // make one

	DB[PROG].appendToRegistry(mime_types);
    }

    /**
     * Return the MIME type of the file object.
     * The implementation in this class calls
     * <code>getContentType(f.getName())</code>.
     *
     * @param f	the file
     * @return	the file's MIME type
     */
    public String getContentType(File f) {
	return this.getContentType(f.getName());
    }

    /**
     * Return the MIME type based on the specified file name.
     * The MIME type entries are searched as described above under
     * <i>MIME types file search order</i>.
     * If no entry is found, the type "application/octet-stream" is returned.
     *
     * @param filename	the file name
     * @return		the file's MIME type
     */
    public synchronized String getContentType(String filename) {
	int dot_pos = filename.lastIndexOf("."); // period index

	if (dot_pos < 0)
	    return defaultType;

	String file_ext = filename.substring(dot_pos + 1);
	if (file_ext.length() == 0)
	    return defaultType;

	for (int i = 0; i < DB.length; i++) {
	    if (DB[i] == null)
		continue;
	    String result = DB[i].getMIMETypeString(file_ext);
	    if (result != null)
		return result;
	}
	return defaultType;
    }

    /**
     * for debugging...
     *
    public static void main(String[] argv) throws Exception {
	MimetypesFileTypeMap map = new MimetypesFileTypeMap();
	System.out.println("File " + argv[0] + " has MIME type " +
						map.getContentType(argv[0]));
	System.exit(0);
    }
    */
}