/*Kristina Laukkonen.
*Uppgift 1.1.2
*En servlet som skriver ut omgivningsvariabler
*/

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import com.oreilly.servlet.VersionDetector;		

public class A112 extends HttpServlet {

	//Skriver ut omgivningsvariabler med hjälp av en PrintWriter

	public void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {

		res.setContentType("text/plain");
		PrintWriter out = res.getWriter();

		HttpSession session = req.getSession();			//Hämtar sessions och ger dess värde
		ServletContext context = getServletContext();	//Hämtar SerlvetContext och ger dess värde

		//skriver ut server-info

		out.println("SERVER-SIDE INFORMATION\n");
		out.println("SERVLET INFORMATION");
		out.println("Servlet name: " + getServletName() + "\n"); //skriver ut namnet på servern
                out.println("****"); 
		out.println("SERVER INFO");
		out.println("Server name: " + req.getServerName());
		out.println("Server port: " + req.getServerPort());
		out.println("Server info: " + context.getServerInfo() + "\n");
                out.println("Server Info version: " + getServerInfoVersion(context.getServerInfo()));
                out.println("****"); 
                out.println("SERVER ATTRIBUTES");

		//skapar element som skrivs ut i "text/plain"

		 Enumeration enum = context.getAttributeNames();
                 while (enum.hasMoreElements()) {
                String name = (String) enum.nextElement();
                out.println("  context.getAttribute(\"" + name + "\"): " +
                     context.getAttribute(name));

                 }

		//skriver ut den Runtime-versions
                 out.println("****"); 
		out.println("RUNTIME VERSIONS");
		out.println("Servlet version: " + VersionDetector.getServletVersion());
		out.println("Java version: " + VersionDetector.getJavaVersion() + "\n");

		//skriver ut klient-information
                out.println("****"); 
		out.println("CLIENT-SIDE INFORMATION");
		out.println("Remote Host: " + req.getRemoteHost());
		out.println("Remote User: " + req.getRemoteUser());
		out.println("Remote Adress: " + req.getRemoteAddr() + "\n");

		//skapar element som skrivs ut i "text/plain"
                out.println("****"); 
		out.println("HEADERS");
		Enumeration names = req.getHeaderNames();
		while (names.hasMoreElements()) {
			String name = (String) names.nextElement();
			Enumeration values = req.getHeaders(name);

			if (values != null) {
				while (values.hasMoreElements()) {
					String value = (String) values.nextElement();
					out.println(" " + names + " : " + value);
				}
			}
		}
	}

	//hämtar SeverInfoName som läggs i "serverInfo"

	private String getServerInfoName(String serverInfo) {
		int slash = serverInfo.indexOf('/');
		if (slash == -1) return serverInfo;
		else return serverInfo.substring (0, slash);
  	}
         // Hämtar version info
    private String getServerInfoVersion(String serverInfo) {
            int slash = serverInfo.indexOf('/');
            if (slash == -1) return null;
            int space = serverInfo.indexOf(' ', slash);
            if (space == -1) space = serverInfo.length();
            return serverInfo.substring(slash + 1, space);
  }
}