/*
 * 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.Map;
import java.util.Map.Entry;
import java.util.concurrent.atomic.AtomicInteger;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;

import digilib.image.DocuImageImpl;
import digilib.io.FileOps;
import digilib.util.Parameter;
import digilib.util.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 DigilibServletConfiguration extends DigilibConfiguration {

    /** time the webapp (i.e. this class) was loaded */
    public final Long webappStartTime = System.currentTimeMillis();
    
    /** counter for HttpRequests (mostly for debugging) */
    public AtomicInteger webappRequestCnt = new AtomicInteger(0);

    /** counter for open HttpRequests (mostly for debugging) */
    public AtomicInteger openRequestCnt = new AtomicInteger(0);

    /**
     * Definition of parameters and default values.
     */
    protected void initParams() {
        /*
         * 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.getVersion(),
                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.ImageLoaderDocuImage.class, null, 's');
        // DocuImage version
        newParameter("servlet.docuimage.version",
                "?", null, 's');
        // AuthOps instance for authentication
        newParameter("servlet.auth.op", null, null, 's');
        // Executor for image operations
        newParameter("servlet.worker.imageexecutor", null, null, 's');
        // Executor for PDF operations
        newParameter("servlet.worker.pdfexecutor", null, null, 's');
        // Executor for PDF-image operations
        newParameter("servlet.worker.pdfimageexecutor", 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("img/digilib-error.png"), null,
                'f');
        // image file to send if access is denied
        newParameter("denied-image", new File("img/digilib-denied.png"), null,
                'f');
        // image file to send if image file not found
        newParameter("notfound-image", new File("img/digilib-notfound.png"),
                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');
        // Type of DocuImage instance
        newParameter("docuimage-class", "digilib.image.ImageLoaderDocuImage", 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');
        // number of working threads
        newParameter("worker-threads", new Integer(1), null, 'f');
        // max number of waiting threads
        newParameter("max-waiting-threads", new Integer(20), null, 'f');
        // timeout for worker threads (ms)
        newParameter("worker-timeout", new Integer(60000), null, 'f');
        // number of pdf-generation threads
        newParameter("pdf-worker-threads", new Integer(1), null, 'f');
        // max number of waiting pdf-generation threads
        newParameter("pdf-max-waiting-threads", new Integer(20), null, 'f');
        // number of pdf-image generation threads
        newParameter("pdf-image-worker-threads", new Integer(1), null, 'f');
        // max number of waiting pdf-image generation threads
        newParameter("pdf-image-max-waiting-threads", new Integer(10), null,
                'f');
        // PDF generation temp directory
        newParameter("pdf-temp-dir", "pdf_temp", null, 'f');
        // PDF generation cache directory
        newParameter("pdf-cache-dir", "pdf_cache", null, 'f');
        // allow image toolkit to use disk cache
        newParameter("img-diskcache-allowed", Boolean.TRUE, null, 'f');
        // default type of error message (image, text, code)
        newParameter("default-errmsg-type", "image", 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 DigilibServletConfiguration(ServletContext c) throws Exception {
        readConfig(c);
    }

    /**
     * read parameter list from the XML file in init parameter "config-file" or
     * file digilib-config.xml
     */
    @SuppressWarnings("unchecked")
    public void readConfig(ServletContext 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<String, String> confTable = lilo.loadURL(f.toURL().toString());

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

        /*
         * read parameters
         */

        for (Entry<String, String> confEntry : confTable.entrySet()) {
            Parameter p = get(confEntry.getKey());
            if (p != null) {
                if (p.getType() == 's') {
                    // type 's' Parameters are not overwritten.
                    continue;
                }
                if (!p.setValueFromString(confEntry.getValue())) {
                    /*
                     * automatic conversion failed -- try special cases
                     */

                    // basedir-list
                    if (confEntry.getKey().equals("basedir-list")) {
                        // split list into directories
                        String[] dirs = FileOps.pathToArray(confEntry.getValue());
                        for (int j = 0; j < dirs.length; j++) {
                            // make relative directory paths be inside the webapp
                            dirs[j] = ServletOps.getFile(dirs[j], c);
                        }
                        if (dirs != null) {
                            p.setValue(dirs);
                        }
                    }
                }
            } else {
                // parameter unknown -- just add
                newParameter(confEntry.getKey(), null, confEntry.getValue(), 'f');
            }
        }
        // initialise static DocuImage class instance
        DigilibServletConfiguration.docuImageClass = (Class<DocuImageImpl>) Class
                .forName(getAsString("docuimage-class"));
        setValue("servlet.docuimage.version", getDocuImageInstance().getVersion());
    }

}