/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2002-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Axis" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.axis.configuration;

import org.apache.axis.AxisProperties;
import org.apache.axis.ConfigurationException;
import org.apache.axis.EngineConfiguration;
import org.apache.axis.EngineConfigurationFactory;
import org.apache.axis.components.logger.LogFactory;
import org.apache.axis.server.AxisServer;
import org.apache.axis.utils.ClassUtils;
import org.apache.axis.utils.Messages;
import org.apache.commons.logging.Log;

import javax.servlet.ServletContext;
import java.io.File;
import java.io.InputStream;

/**
 * This is a default implementation of ServletEngineConfigurationFactory.
 * It is user-overrideable by a system property without affecting
 * the caller. If you decide to override it, use delegation if
 * you want to inherit the behaviour of this class as using
 * class extension will result in tight loops. That is, your
 * class should implement EngineConfigurationFactory and keep
 * an instance of this class in a member field and delegate
 * methods to that instance when the default behaviour is
 * required.
 *
 * @author Richard A. Sitze
 * @author Davanum Srinivas (dims@apache.org)
 */
public class EngineConfigurationFactoryServlet
        extends EngineConfigurationFactoryDefault
{
   private static Log log =
           LogFactory.getLog(EngineConfigurationFactoryServlet.class.getName());

   private ServletContext ctx;

   /**
    * Creates and returns a new EngineConfigurationFactory.
    * If a factory cannot be created, return 'null'.
    * <p/>
    * The factory may return non-NULL only if:
    * - it knows what to do with the param (param instanceof ServletContext)
    * - it can find it's configuration information
    *
    * @see org.apache.axis.configuration.EngineConfigurationFactoryFinder
    */
   public static EngineConfigurationFactory newFactory(Object param)
   {
      /**
       * Default, let this one go through if we find a ServletContext.
       *
       * The REAL reason we are not trying to make any
       * decision here is because it's impossible
       * (without refactoring FileProvider) to determine
       * if a *.wsdd file is present or not until the configuration
       * is bound to an engine.
       *
       * FileProvider/EngineConfiguration pretend to be independent,
       * but they are tightly bound to an engine instance...
       */
      return (param instanceof ServletContext)
              ? new EngineConfigurationFactoryServlet((ServletContext)param)
              : null;
   }

   /**
    * Create the default engine configuration and detect whether the user
    * has overridden this with their own.
    */
   protected EngineConfigurationFactoryServlet(ServletContext ctx)
   {
      super();
      this.ctx = ctx;
   }

   /**
    * Get a default server engine configuration.
    *
    * @return a server EngineConfiguration
    */
   public EngineConfiguration getServerEngineConfig()
   {
      return getServerEngineConfig(ctx);
   }

   /**
    * Get a default server engine configuration in a servlet environment.
    *
    * @param ctx a ServletContext
    * @return a server EngineConfiguration
    */
   private static
   EngineConfiguration getServerEngineConfig(ServletContext ctx)
   {
      // Respect the system property setting for a different config file
      String configFile =
              AxisProperties.getProperty(OPTION_SERVER_CONFIG_FILE);
      if (configFile == null)
      {
         configFile = SERVER_CONFIG_FILE;
      }

      /**
       * Flow can be confusing.  Here is the logic:
       * 1) Make all attempts to open resource IF it exists
       *    - If it exists as a file, open as file (r/w)
       *    - If not a file, it may still be accessable as a stream (r)
       *    (env will handle security checks).
       * 2) If it doesn't exist, allow it to be opened/created
       *
       * Now, the way this is done below is:
       * a) If the file does NOT exist, attempt to open as a stream (r)
       * b) Open named file (opens existing file, creates if not avail).
       */

      /*
       * Use the WEB-INF directory
       * (so the config files can't get snooped by a browser)
       */
      String appWebInfPath = "/WEB-INF";

      FileProvider config = null;

      String realWebInfPath = ctx.getRealPath(appWebInfPath);

      /**
       * If path/file doesn't exist, it may still be accessible
       * as a resource-stream (i.e. it may be packaged in a JAR
       * or WAR file).
       */
      if (realWebInfPath == null ||
              !(new File(realWebInfPath, configFile)).exists())
      {
         String name = appWebInfPath + "/" + configFile;
         InputStream is = ctx.getResourceAsStream(name);
         if (is != null)
         {
            // FileProvider assumes responsibility for 'is':
            // do NOT call is.close().
            config = new FileProvider(is);
         }

         if (config == null)
         {
            log.error(Messages.getMessage("servletEngineWebInfError03",
                    name));
         }
      }

      /**
       * Couldn't get data  OR  file does exist.
       * If we have a path, then attempt to either open
       * the existing file, or create an (empty) file.
       */
      if (config == null && realWebInfPath != null)
      {
         try
         {
            config = new FileProvider(realWebInfPath, configFile);
         }
         catch (ConfigurationException e)
         {
            log.error(Messages.getMessage("servletEngineWebInfError00"), e);
         }
      }

      /**
       * Fall back to config file packaged with AxisEngine
       */
      if (config == null)
      {
         log.warn(Messages.getMessage("servletEngineWebInfWarn00"));
         try
         {
            InputStream is =
                    ClassUtils.getResourceAsStream(AxisServer.class,
                            SERVER_CONFIG_FILE);
            config = new FileProvider(is);
         }
         catch (Exception e)
         {
            log.error(Messages.getMessage("servletEngineWebInfError02"), e);
         }
      }

      return config;
   }
}
