package Serfler;

//    Serfler - an Http server written in Java based on servlets
//    Copyright (c) 1998 by Douglas Harris <doug@mscs.mu.edu>
//    Distributed under the GNU General Public License
//    <http://www.fsf.org/coopyleft/gpl.html>
//    A copy is included with this software distribution.
//    The package is available from
//    http://spectral.mscs.mu.edu/javadev/src/serfler.zip
//    

import javax.servlet.*;
import java.util.*;
import java.io.*;

public class SerflerContext extends ClassLoader implements ServletContext{
  static Hashtable localServlets = new Hashtable();
  static Properties serflerProperties;
  static public String sDocumentRoot="/"; // Should start and end with slash
  static public String sImageDirectory="/images"; // Should start and end with slash
  static public String sServletDirectory="/javadev/servletCode";

  static String sServerInfo="WebServlet 0.5";;
  static PrintWriter sServerLogWriter = new PrintWriter(System.err);
  String sLogFileName="/tmp/serfler.log";
  ServletConfig serflerConfig = new Serfler.SerflerConfig();
  public static Servlet qFileServlet;
  public static Servlet qLoadServlet;
  public static Servlet qDefaultServlet;
  public static Servlet qUnknownServlet;
  public static Servlet qErrorServlet;

  public SerflerContext(){
  }

  public void init(Properties serflerProperties){
    this.serflerProperties=serflerProperties;
    sDocumentRoot=serflerProperties.getProperty("document.dir",sDocumentRoot);
System.out.println("sDocumentRoot: "+sDocumentRoot);
    sServletDirectory=serflerProperties.getProperty("servlet.code",sServletDirectory);
System.out.println("sServletDirectory: "+sServletDirectory);
    sImageDirectory=serflerProperties.getProperty("image.dir",sImageDirectory);
System.out.println("sImageDirectory: "+sImageDirectory);
    sLogFileName= serflerProperties.getProperty("server.log", sLogFileName);
System.out.println("sLogFileName: "+sLogFileName);
    try{
      sServerLogWriter = new PrintWriter(new FileOutputStream(sLogFileName),true);
System.out.println("Logging at:" + sLogFileName);
    } catch(IOException x){
      log(x,"Changing log file to "+sLogFileName);
    }
  }

/*
 *    START  implementation of ServletContext
 */

  /**
   * Enumerates the servlets in this context (server). Only servlets
   * that are accessible will be returned. The enumeration always
   * includes the servlet itself.
   */

  public Enumeration getServletNames(){
    return localServlets.keys();
  }

// DEPRECATED
  public Enumeration getServlets(){
    return getServletNames();
  }

  /**
   * Returns the servlet for the specified name.
   * @param name the name of the servlet
   * @return the Servlet, or null if not found
   * @exception ServletException if the servlet could not be initialized
   */
  public Servlet getServlet(String name) throws ServletException{
    return (Servlet)localServlets.get(name);
  }


  /**
   * Writes a message to the servlet log file.
   * @param msg the message to be written
   */
  public void log(String msg){
     Date date=new Date(System.currentTimeMillis());
     String head="["+date.toString()+"] ";
     sServerLogWriter.println(head+msg);
  //System.out.println("LOG: "+head+msg);
  }

  /**
   * Writes a message to the servlet log file.
   * @param msg the message to be written
   */
  public void log(Exception x, String msg){
     log(x.toString()+": "+msg);
  }

  /**
   * Applies alias rules to the specified virtual path and returns the
   * corresponding real path. Returns null if the translation could not
   * be performed.
   * @param path the real path to be translated
   */
  public String getRealPath(String path){
    int index;
    String prefix="/images";
    if (path.equals(prefix)){
      path=sImageDirectory;
      return path.replace('/',File.separatorChar);
    }
    if (path.startsWith(prefix+"/")){
      path=sImageDirectory+path.substring(prefix.length());
      return path.replace('/',File.separatorChar);
    }

  // JDH Do any more aliasing needed here
    if (path.startsWith("/~")){
      path=path.substring(2);
      index=path.indexOf("/");
      if (index<0){
        path="/home/"+path+"/public_html";
      }else{
	path="/home/"+path.substring(0,index+1)+"public_html"+path.substring(index);
      }
    }else{
      if (path.startsWith("/")){
        path=path.substring(1);
      }
      if (!sDocumentRoot.startsWith("/")){
        sDocumentRoot="/"+sDocumentRoot;
      }
      if (!sDocumentRoot.endsWith("/")){
        sDocumentRoot=sDocumentRoot+"/";
      }
      path=sDocumentRoot+path;
      if (path.equals("/")){
        path="/../";
      }
    }
    return path.replace('/',File.separatorChar);
  }

  /**
   * Returns the mime type of the specified file, or null if not known.
   * @param file file name whose mime type is required
   */
  public String getMimeType(String file){
    return Utilities.MimeProperties.getMimeType(file);
  }

  /**
   * Returns the name and version of the Web server under which the
   * servlet is running. Same as the CGI variable SERVER_SOFTWARE.
   */
  public String getServerInfo(){
    return sServerInfo;
  }

  /**
   * Returns an attribute of the server given the specified key name.
   * This allows access to additional information about the server not
   * already provided by the other methods in this interface. Attribute
   * names should follow the same convention as package names, and those
   * beginning with 'com.sun.*' are reserved for use by Sun Microsystems.
   * @param name the attribute key name
   * @return the value of the attribute, or null if not defined
   */
  public Object getAttribute(String name){
    return null;
  }

/*
 *   END    implementation of ServletContext
 */

/*
 *   START  loader code
 */
/*
 *   Added loadClass for JDK1.1 compatibility
 *   Just remove it  for JDK1.2
*/
  public synchronized Class loadClass(String className, boolean resolve)
    throws ClassNotFoundException{
    Class c=null;
    c=findSystemClass(className);
    if (c==null){
      c=findLoadedClass(className);
    }
    if (c==null){
      c=findLocalClass(className);
    }
    if (resolve && c!=null){
      resolveClass(c);
    }
    return c;
  }

  public synchronized Class findLocalClass(String className){
    Class c=null;
    byte[] byteCode = getClassByteCode(className);
    if (byteCode != null) {
      c=(defineClass(className, byteCode, 0, byteCode.length));
    }
    return c;
  }

  private byte[] getClassByteCode(String className){
    byte result[];
    String fileName=
      sServletDirectory+File.separatorChar+className+".class";
    try {
      FileInputStream i = new FileInputStream(fileName);
      result = new byte[i.available()];
      i.read(result);
      return result;
    } catch (Exception x){
          return null;
    }
  }


  public Servlet getServletInstance(String servletClassName){
    Class servletClass=null;
    Servlet servletInstance=null;
    try{
      servletClass=loadClass(servletClassName);
      if (servletClass!=null){
        servletInstance=(Servlet)servletClass.newInstance();
      }
    } catch(IllegalAccessException x){
      log("getServletInstance: threw "+x.toString());
    } catch(InstantiationException x){
      log("getServletInstance: threw "+x.toString());
    } catch(ClassNotFoundException x){
      log("getServletInstance: threw "+x.toString());
    } catch(ClassCastException x){
      log("getServletInstance: threw "+x.toString());
    }
    return servletInstance;
  }

  public boolean addServlet(String name, Servlet instance){
     ServletConfig cfg=(ServletConfig)new SerflerConfig(this);
     return addServlet(name, instance, cfg);
  }

  public boolean addServlet(String name, Servlet inst, ServletConfig cfg){
    boolean isOK=false;
    String logString="addServlet("+name+", inst, cfg)";
    try{
      inst.init(cfg);
      localServlets.put(name, inst);
      isOK=true;
    }catch (Exception x){
      log(x,logString);
    }finally{
      return isOK;
    }
  }

  public void loadSerflerServlets(){
    try{
    qFileServlet = getServletInstance("Serfler.Servlet.FileServlet");
    if (qFileServlet==null){
      System.err.println("No File Servlet");
      System.exit(10);
    }
    qFileServlet.init(serflerConfig);
    qLoadServlet =getServletInstance("Serfler.Servlet.LoadServlet");
    if (qFileServlet==null){
      System.err.println("No Load Servlet");
      System.exit(10);
    }
    qLoadServlet.init(serflerConfig);
    qDefaultServlet =getServletInstance("Serfler.Servlet.DefaultServlet");
    if (qFileServlet==null){
      System.err.println("No Default Servlet");
      System.exit(10);
    }
    qDefaultServlet.init(serflerConfig);
    qUnknownServlet =getServletInstance("Serfler.Servlet.UnknownServlet");
    if (qFileServlet==null){
      System.err.println("No Unknown Servlet");
      System.exit(10);
    }
    qUnknownServlet.init(serflerConfig);
    qErrorServlet = getServletInstance("Serfler.Servlet.ErrorServlet");
    if (qFileServlet==null){
      System.err.println("No Error Servlet");
      System.exit(10);
    }
    qErrorServlet.init(serflerConfig);
    } catch(ServletException x){
      x.printStackTrace(System.out);
      System.exit(1);
    }
  }

  public void setServlets(){
    if (!addServlet("hello",getServletInstance("HelloWorldServlet"))){
      log("addServlet(hello) failed");
    }
    if (!addServlet("simple",getServletInstance("SimpleServlet"))){
      log("addServlet(simple) failed");
    }
    if (!addServlet("date",getServletInstance("DateServlet"))){
      log("addServlet(date) failed");
    }
    if (!addServlet("snoop",getServletInstance("SnoopServlet"))){
      log("addServlet(snoop) failed");
    }
    /*JDH Use properties file for more*/
  }

  public static void main(String[] args){
    SerflerContext loader = new SerflerContext();
    if (loader==null){
      System.err.println("No loader!");
      System.exit(1);
    }
    Servlet servlet;
    loader.loadSerflerServlets();
    loader.setServlets();
    for (int i=0;i<args.length;i++){
      try{
        servlet=loader.getServlet(args[i]);
      } catch(Exception x){
        System.err.println("at "+i+" "+x.toString());
      }
    }
  }
}