/*
 * DigilibConfiguration -- Holding all parameters for digilib servlet.
 * 
 * Digital Image Library servlet components
 * 
 * Copyright (C) 2001, 2002 Robert Casties (robcast@mail.berlios.de)
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 * 
 * Please read license.txt for the full details. A copy of the GPL may be found
 * at http://www.gnu.org/copyleft/lgpl.html
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA 02111-1307 USA
 *  
 */

package digilib.servlet;

import java.io.File;
import java.util.Iterator;
import java.util.Map;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;

import digilib.image.DocuImage;
import digilib.image.DocuImageImpl;
import digilib.io.FileOps;
import digilib.io.XMLListLoader;

/**
 * Class to hold the digilib servlet configuration parameters. The parameters
 * can be read from the digilib-config file and be passed to other servlets or
 * beans. <br>errorImgFileName: image file to send in case of error. <br>
 * denyImgFileName: image file to send if access is denied. <br>baseDirs:
 * array of base directories in order of preference (prescaled versions first).
 * <br>useAuth: use authentication information. <br>authConfPath:
 * authentication configuration file. <br>... <br>
 * 
 * @author casties
 *  
 */
public class DigilibConfiguration extends ParameterMap {

	private static final long serialVersionUID = -6630487070791637120L;

	/** DocuImage class instance */
	private Class docuImageClass = null;

	/** Log4J logger */
	private Logger logger = Logger.getLogger("digilib.config");

	/**
	 * Default constructor defines all parameters and their default values.
	 *  
	 */
	public DigilibConfiguration() {
		// create HashMap(20)
		super(20);
		// we start with a default logger config
		BasicConfigurator.configure();

		/*
		 * Definition of parameters and default values. System parameters that
		 * are not read from config file have a type 's'.
		 */

		// digilib servlet version
		newParameter(
			"servlet.version",
			digilib.servlet.Scaler.dlVersion,
			null,
			's');
		// configuration file location
		newParameter("servlet.config.file", null, null, 's');
		// DocuDirCache instance
		newParameter("servlet.dir.cache", null, null, 's');
		// DocuImage class instance
		newParameter(
			"servlet.docuimage.class",
			digilib.image.JAIDocuImage.class,
			null,
			's');
		// AuthOps instance for authentication
		newParameter("servlet.auth.op", null, null, 's');
		// worker queues
		newParameter("servlet.fast.queue", null, null, 's');
		newParameter("servlet.slow.queue", null, null, 's');

		/*
		 * parameters that can be read from config file have a type 'f'
		 */

		// image file to send in case of error
		newParameter(
			"error-image",
			new File("/docuserver/images/icons/scalerror.gif"),
			null,
			'f');
		// image file to send if access is denied
		newParameter(
			"denied-image",
			new File("/docuserver/images/icons/denied.gif"),
			null,
			'f');
		// base directories in order of preference (prescaled versions last)
		String[] bd = { "/docuserver/images", "/docuserver/scaled/small" };
		newParameter("basedir-list", bd, null, 'f');
		// use authentication information
		newParameter("use-authorization", Boolean.FALSE, null, 'f');
		// authentication configuration file
		newParameter("auth-file", new File("digilib-auth.xml"), null, 'f');
		// sending image files as-is allowed
		newParameter("sendfile-allowed", Boolean.TRUE, null, 'f');
		// Debug level
		newParameter("debug-level", new Integer(5), null, 'f');
		// Type of DocuImage instance
		newParameter(
			"docuimage-class",
			"digilib.image.JAIDocuImage",
			null,
			'f');
		// part of URL used to indicate authorized access
		newParameter("auth-url-path", "authenticated/", null, 'f');
		// degree of subsampling on image load
		newParameter("subsample-minimum", new Float(2f), null, 'f');
		// default scaling quality
		newParameter("default-quality", new Integer(1), null, 'f');
		// use mapping file to translate paths
		newParameter("use-mapping", Boolean.FALSE, null, 'f');
		// mapping file location
		newParameter("mapping-file", new File("digilib-map.xml"), null, 'f');
		// log4j config file location
		newParameter("log-config-file", new File("log4j-config.xml"), null, 'f');
		// maximum destination image size (0 means no limit)
		newParameter("max-image-size", new Integer(0), null, 'f');
		// use safe (but slower) directory indexing
		newParameter("safe-dir-index", Boolean.FALSE, null, 'f');
		// number of fast worker threads
		newParameter("worker-fast-lanes", new Integer(2), null, 'f');
		// length of fast worker queue
		newParameter("worker-fast-queue", new Integer(100), null, 'f');
		// number of slow worker threads
		newParameter("worker-slow-lanes", new Integer(2), null, 'f');
		// length of slow worker queue
		newParameter("worker-slow-queue", new Integer(100), null, 'f');

	}

	/**
	 * Constructor taking a ServletConfig. Reads the config file location from
	 * an init parameter and loads the config file. Calls <code>readConfig()</code>.
	 * 
	 * @see readConfig()
	 */
	public DigilibConfiguration(ServletConfig c) throws Exception {
		this();
		readConfig(c);
	}

	/**
	 * read parameter list from the XML file in init parameter "config-file"
	 */
	public void readConfig(ServletConfig c) throws Exception {

		/*
		 * Get config file name. The file name is first looked for as an init
		 * parameter, then in a fixed location in the webapp.
		 */
		if (c == null) {
			// no config no file...
			return;
		}
		String fn = c.getInitParameter("config-file");
		if (fn == null) {
			fn = ServletOps.getConfigFile("digilib-config.xml", c);
			if (fn == null) {
				logger.fatal("readConfig: no param config-file");
				throw new ServletException("ERROR: no digilib config file!");
			}
		}
		File f = new File(fn);
		// setup config file list reader
		XMLListLoader lilo =
			new XMLListLoader("digilib-config", "parameter", "name", "value");
		// read config file into HashMap
		Map confTable = lilo.loadURL(f.toURL().toString());

		// set config file path parameter
		setValue("servlet.config.file", f.getCanonicalPath());

		/*
		 * read parameters
		 */

		for (Iterator i = confTable.keySet().iterator(); i.hasNext();) {
			String key = (String) i.next();
			String val = (String) confTable.get(key);
			Parameter p = get(key);
			if (p != null) {
				if (p.getType() == 's') {
					// type 's' Parameters are not overwritten.
					continue;
				}
				if (!p.setValueFromString(val)) {
					/*
					 * automatic conversion failed -- try special cases
					 */

					// basedir-list
					if (key.equals("basedir-list")) {
						// split list into directories
						String[] sa = FileOps.pathToArray(val);
						if (sa != null) {
							p.setValue(sa);
						}
					}

				}
			} else {
				// parameter unknown -- just add
				newParameter(key, null, val, 'f');
			}
		}

	}

	/**
	 * Creates a new DocuImage instance.
	 * 
	 * The type of DocuImage is specified by docuImageType.
	 * 
	 * @return DocuImage
	 */
	public DocuImage getDocuImageInstance() {
		DocuImageImpl di = null;
		try {
			if (docuImageClass == null) {
				docuImageClass = Class.forName(getAsString("docuimage-class"));
			}
			di = (DocuImageImpl) docuImageClass.newInstance();
		} catch (Exception e) {
		}
		return di;
	}

	/**
	 * @return Returns the docuImageClass.
	 */
	public Class getDocuImageClass() {
		return docuImageClass;
	}
	/**
	 * @param docuImageClass The docuImageClass to set.
	 */
	public void setDocuImageClass(Class docuImageClass) {
		this.docuImageClass = docuImageClass;
	}
}