// GuestBookServlet, based on example from http://www.oreilly.com/catalog/msql/servlet.txt
// Very loosely based, as it turns out.  I couldn't find adequate documentation to make that work.

// This version uses Jetty.
// javac -classpath org.mortbay.jetty.jar;javax.servlet.jar GuestBookServlet.java
// java -cp msql-connector-java-3.0.8-stable-bin.jar;org.mortbay.jetty.jar GuestBookServlet

/* Here's how to build the database:
mysqladmin create GUESTBOOK
mysql <<DONE
use GUESTBOOK;
create table comments (comment_id int primary key not null auto_increment,
                       name varchar(40) not null, date varchar(30), comment varchar(255));
quit
DONE
*/ 

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.IOException;
import java.sql.*;
import java.text.DateFormat;
import java.util.Properties;
import java.util.Random;
import org.mortbay.http.*;  // Jetty org.mortbay.jetty.jar
import org.mortbay.jetty.servlet.*;  // Jetty org.mortbay.jetty.jar

public class GuestBookServlet extends HttpServlet implements SingleThreadModel {
    static final String driverName          = "com.mysql.jdbc.Driver";
    static final String jdbcURL1            = "jdbc:mysql://127.0.0.1/";
    static final String databaseName        = "GUESTBOOK";
    static final String userName            = "rowland";
    static String userPassword              = "";
    static final String URI                 = "gb";
    static final String port                = "8080"; 
    static final String className           = "GuestBookServlet";
    private Driver     driver               = null;
    private Random     random               = new Random();
    protected static HttpServer server;

    protected void openDriver() throws Exception {
	if (driver!= null)  return;  // already done
	println("Instantiating "+ driverName);
	driver = (Driver)Class.forName(driverName).newInstance();
	if (driver== null)  throw new SQLException("newInstance of "+ driverName+ "returned NULL!");
    }

    protected Connection openConnection()  throws Exception {
	// return null if failed to connect
	openDriver();
	println("  Connecting "+ jdbcURL1+ databaseName);
	Connection conn;
	conn= DriverManager.getConnection(jdbcURL1+ databaseName, userName, userPassword);
	//[Not for Msql or MySql]conn.setAutoCommit(false);
	println("  ...connected");
	return conn;
    }

    public void init(ServletConfig cfg) throws ServletException {
	// Called the first time a servlet is invoked
	super.init(cfg);
	println("init() called");
	try {
	    openDriver();
	}
        catch( Exception e ) {
            throw new ServletException("EXC init(): " + e.getMessage());
        }
    }

    protected String curDateString() {
	java.util.Date date= new java.util.Date();
	return DateFormat.getDateTimeInstance().format(date);
    }

    protected static void println(String s) {
	java.util.Date d= new java.util.Date();
	System.out.println(d.getTime()%10000+ ": "+ s);
    }

    public void doGet(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException {
	println("doGet called...");
        ServletOutputStream out = res.getOutputStream();
        int id = -1;

        res.setContentType("text/html");
        printPageHeader(out);
        printCommentForm(out);
        printComments(out);
        printPageFooter(out);
	println("...doGet done");
    }

    public void doPost(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException {
	println("doPost called");
        ServletOutputStream out = res.getOutputStream();
        String date = curDateString();
        String name, comment;
        Connection conn = null;
        Exception err = null;
        int id = -1;
        String[] tmp;

        // get the form values
        tmp = req.getParameterValues("name");
        if( tmp == null || tmp.length != 1 ) {
            name = null;
        }
        else {
            name = tmp[0];
        }
        tmp = req.getParameterValues("comments");
        if( tmp == null || tmp.length != 1 ) {
            comment = null;
        }
        else {
            comment = tmp[0];
        }
        res.setContentType("text/html");
        printPageHeader(out);
        // validate values
        if( name.length() < 1 ) {
            out.println("You must specify a valid name!");
            printCommentForm(out);
            printPageFooter(out);
            return;
        }
        if( comment.length() < 1 ) {
            out.println("You left no comments!");
            printCommentForm(out);
            printPageFooter(out);
            return;
        }
        try {
            ResultSet result;
            Statement stmt;
	    
	    conn= openConnection();
            stmt = conn.createStatement();
            comment = fixComment(comment);
            stmt.executeUpdate("INSERT into comments (comment_id, name, comment, date) "+
                               "VALUES (0, '" + name + "', '" +
                               comment + "', '" + date + "')");
            //[Not for Msql or MySql]conn.commit();
            stmt.close();
        }
        catch( Exception e ) {
            e.printStackTrace();
            err = e;
        }
        finally {
            if( conn != null ) {
                try { conn.close(); }
                catch( Exception e ) { }
            }
        }
        if( err != null ) {
            out.println("An error occurred on save: " + err.getMessage());
        }
        else {
            printCommentForm(out);
            printComments(out);
        }
	println("...doPost done");
    }

    public String getServletInfo() {
        return "Guest Book Servlet\nFrom MySQL and mSQL";
    }

    private void printCommentForm(ServletOutputStream out)
        throws IOException {
	println("  printCommentForm()");
        out.println("<CENTER>");
        out.println("<FORM ACTION=\"/"+ URI+ "\" METHOD=\"POST\">");
        out.println("<TABLE>");
        out.println("<TR ALIGN=\"LEFT\">");
        out.println("<TD>Name:</TD>");
        out.println("<TD><INPUT TYPE=\"TEXT\" NAME=\"name\" SIZE=30></TD>");
        out.println("<TD><INPUT TYPE=\"SUBMIT\" VALUE=\"Save\"></TD>");
        out.println("</TR>");
        out.println("<TR ALIGN=\"LEFT\">");
        out.println("</TR>");
        out.println("<TR ALIGN=\"LEFT\">");
        out.println("<TD>Comments:</TD>");
        out.println("</TR>");
        out.println("<TR ALIGN=\"CENTER\">");
        out.println("<TD COLSPAN=3>");
        out.println("<TEXTAREA NAME=\"comments\" COLS=40 ROWS=7>");
        out.println("</TEXTAREA></TD>");
        out.println("</TR>");
        out.println("</TABLE>");
        out.println("</FORM>");
        out.println("</CENTER>");
    }

    private void printComments(ServletOutputStream out)
        throws IOException {
        Connection conn = null;
	
	println("  printComments()");
        try {
            ResultSet results;
            Statement stmt;
            int rows, count;
	    
            conn = openConnection();
            stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                                        ResultSet.CONCUR_READ_ONLY);
            results = stmt.executeQuery("SELECT name, date, " +
                                        "comment, comment_id " +
                                        "FROM comments " +
                                        "ORDER BY comment_id");
	    println("  ...SELECT FROM comments");
            out.println("<DL>");
            results.last();
            count = 0;
            // print up to 5 rows going backwards
            while (count < 5) {
                String name, cmt, date;

                name = results.getString(1);
                if( results.wasNull() ) name = "Unknown User";
                date = results.getString(2);
                if( results.wasNull() ) date = curDateString();
                cmt = results.getString(3);
                if( results.wasNull() )  cmt= "No comment";
                out.println("<DT><B>" + name + "</B>  on " + date);
                cmt = noHTML(cmt);
                out.println("<DD> <PRE>" + cmt + "</PRE>");
		if (!results.previous())  break;  // no more.
                count++;
            }
            out.println("</DL>");
        }
        catch( Exception e ) {
            out.println("Error: " + e.getMessage());
	    println("EXC printComments(): " + e.getMessage());
	    e.printStackTrace();
        }
        finally {
            if( conn != null ) {
                try { conn.close(); }
                catch( SQLException e ) { }
            }
        }
    }
    
    private void printPageHeader(ServletOutputStream out)
        throws IOException {
        out.println("<HTML>");
        out.println("<HEAD>");
        out.println("<TITLE>Guest Book</TITLE>");
        out.println("</HEAD>");
        out.println("<BODY>");
        out.println("<CENTER><H1><B>Guest Book</B></FONT></CENTER>");
    }

    private void printPageFooter(ServletOutputStream out)
        throws IOException {
        out.println("</BODY>");
        out.println("</HTML>");
        out.flush();
    }

    private String noHTML(String cmt) {
	int ilt= cmt.indexOf('<');
	int igt= cmt.indexOf('>');
	if (ilt< 0 && igt< 0)
	    return cmt;
	
	String tmp = "";
	
	for (int i=0; i<cmt.length(); i++) {
	    char c = cmt.charAt(i);
	    if( c == '<' ) tmp = tmp + "&lt;";
	    else if( c == '>' )   tmp = tmp + "&gt;";
	    else  tmp = tmp + c;
	}
        return tmp;
    }

    private String fixComment(String comment) {
        if( comment.indexOf('\'') != -1 ) {
            String tmp = "";
	    
            for(int i=0; i<comment.length(); i++) {
                char c = comment.charAt(i);
                if( c == '\'' )  tmp = tmp + "\\'";
                else  tmp = tmp + c;
            }
            comment = tmp;
        }
        return comment;
    }


    //----------------------------------------------------------------------------------------

    static void realityCheck() {
	try {
	/*
	    Class thisClass= Class.forName(className);
	    ClassLoader loader= thisClass.getClassLoader();
	    Object temp= new GuestBookServlet();
	    Class tempClass= temp.getClass();
	    if (thisClass!= tempClass)
	      System.err.println("realityCheck: class discrepancy");
	    String tempClassName= thisClass.getName();
	    if (!tempClassName.equals(className))
		System.err.println("realityCheck: class name discrepancy, "+
				   tempClassName+ " should be "+ className);

	    HttpContext context= server.getContext("/");
	    HttpHandler handlers[]= context.getHandlers();
	    ServletHandler handler= (ServletHandler)handlers[0];
	    ServletHolder servletHolders[]= handler.getServlets();
	    int i;
	    for (i=0; i< servletHolders.length; i++) {
		Servlet servlet= servletHolders[i].getServlet(); // will call init()!
		System.out.println(servlet.getServletInfo());
	    }
	*/
	    GuestBookServlet temp= new GuestBookServlet();
	    temp.openDriver();
	    Connection conn= temp.openConnection();
            Statement stmt = conn.createStatement();
            ResultSet result = stmt.executeQuery("SELECT name " +
                                       "FROM comments WHERE comment_id = 0");
	} catch (Exception E) {
	    System.err.println("EXC realityCheck: "+ E.getMessage());
	    E.printStackTrace();
	    System.exit(-1);
	}
    }

    static void startServer()  {
	try {
	    // Will be seen as http://localhost:8080/gb/
	    System.out.println("Building HttpServer");
	    server= new HttpServer();
	    System.out.println("  Adding Listener to server at port "+ port);
	    server.addListener(":"+ port);
	    System.out.println("  Getting root context from server");
	    HttpContext context= server.getContext("/");
	    ServletHandler handler= new ServletHandler();
	    System.out.println("  Adding Servlet to handler at http://localhost:"+ port+ "/" +URI+ "/");
	    handler.addServlet("/"+ URI+ "/*", className);
	    System.out.println("  Adding Handler to root context");
	    context.addHandler(handler);
	    System.out.println("Starting server");
	    server.start();
	    System.out.println("Started server");
	} catch (Exception E) {
	    System.err.println("EXC serve: "+ E.getMessage());
	    E.printStackTrace();
	}
    }

    public static void main(String args[]) {
	if (args.length>= 1) {
	    userPassword= args[0];
	    System.out.print(args[0]);
	}
	startServer();
	realityCheck();
    }
}