// This file is copied from:
// http://www.brics.dk/ixwt/examples/FileServer.java
// -Ian! D. Allen - idallen@idallen.ca - www.idallen.com

import java.net.*;
import java.io.*;
import java.util.*;

public class FileServer {
  int port;
  String wwwhome;

  Socket con;
  BufferedReader in;
  OutputStream out;
  PrintStream pout;

  FileServer(int port, String wwwhome) {
    this.port = port;
    this.wwwhome = wwwhome;
  }

  public static void main(String[] args) {
    if (args.length!=2) {
      System.out.println("Usage: java FileServer <port> <wwwhome>");
      System.exit(-1);
    }
    int port = Integer.parseInt(args[0]);
    String wwwhome = args[1];
    FileServer fs = new FileServer(port, wwwhome);
    fs.run();
  }

  void run() {
    ServerSocket ss = null; 
    try {
      ss = new ServerSocket(port); 
    } catch (IOException e) {
      System.err.println("Could not start server: "+e);
      System.exit(-1);
    }
    System.out.println("FileServer accepting connections on port "+
                       port);
            
    while (true) {
      try {
        con = ss.accept();
        in = new BufferedReader
                   (new InputStreamReader(con.getInputStream()));
        out = new BufferedOutputStream(con.getOutputStream());
        pout = new PrintStream(out);
                
        String request = in.readLine();
        con.shutdownInput(); // ignore the rest
        log(con, request);

        processRequest(request);
                
        pout.flush();
      } catch (IOException e) { 
        System.err.println(e); 
      }
      try {
        if (con!=null) 
          con.close(); 
      } catch (IOException e) { 
        System.err.println(e); 
      }
    }
  }

  void processRequest(String request) throws IOException {
    if (!request.startsWith("GET") || request.length()<14 ||
        !(request.endsWith("HTTP/1.0") || 
          request.endsWith("HTTP/1.1")) ||
        request.charAt(4)!='/') {
      errorReport(pout, con, "400", "Bad Request", 
                  "Your browser sent a request that "+
                  "this server could not understand.");
    } else {
      String req = request.substring(4, request.length()-9).trim();
      if (req.indexOf("/.")!=-1 || req.endsWith("~")) {
        errorReport(pout, con, "403", "Forbidden", 
                    "You don't have permission to access "+
                    "the requested URL.");
      } else {
        String path = wwwhome+"/"+req;
        File f = new File(path);
        if (f.isDirectory() && !path.endsWith("/")) {
          pout.print("HTTP/1.0 301 Moved Permanently\r\n"+
                     "Location: http://"+
                     con.getLocalAddress().getHostAddress()+":"+
                     con.getLocalPort()+req+"/\r\n\r\n");
          log(con, "301 Moved Permanently");
        } else {
          if (f.isDirectory()) { 
            path = path+"index.html";
            f = new File(path);
          }
          try { 
            InputStream file = new FileInputStream(f);
            String contenttype = 
              URLConnection.guessContentTypeFromName(path);
            pout.print("HTTP/1.0 200 OK\r\n");
            if (contenttype!=null)
              pout.print("Content-Type: "+contenttype+"\r\n");
            pout.print("Date: "+new Date()+"\r\n"+
                       "Server: IXWT FileServer 1.0\r\n\r\n");
            sendFile(file, out); // send raw file 
            log(con, "200 OK");
          } catch (FileNotFoundException e) { 
            errorReport(pout, con, "404", "Not Found", 
                        "The requested URL was not found "+
                        "on this server.");
          }
        }
      }
    }
  }
    
  void log(Socket con, String msg) {
    System.err.println(new Date()+" ["+
                       con.getInetAddress().getHostAddress()+
                       ":"+con.getPort()+"] "+msg);
  }
  
  void errorReport(PrintStream pout, Socket con,
                   String code, String title, String msg) {
    pout.print(
      "HTTP/1.0 "+code+" "+title+"\r\n"+
      "\r\n"+
      "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\r\n"+
      "<TITLE>"+code+" "+title+"</TITLE>\r\n"+
      "</HEAD><BODY>\r\n"+
      "<H1>"+title+"</H1>\r\n"+msg+"<P>\r\n"+
      "<HR><ADDRESS>IXWT FileServer 1.0 at "+
      con.getLocalAddress().getHostName()+
      " Port "+con.getLocalPort()+"</ADDRESS>\r\n"+
      "</BODY></HTML>\r\n");
    log(con, code+" "+title);
  }

  void sendFile(InputStream file, OutputStream out) 
      throws IOException {
    byte[] buffer = new byte[1000];
    while (file.available()>0) 
      out.write(buffer, 0, file.read(buffer));
  }
}