import com.mysql.jdbc.Connection;
import java.io.IOException;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import DataDAO.*;
import java.util.Properties;
import java.util.Random;
import javax.mail.*;
import javax.mail.internet.*;
import javax.servlet.RequestDispatcher;

/**
 *
 * @author Yao
 */
public class ForgotPassword extends HttpServlet {

    private static Connection con;
    private String user = null;
    private String pw_con = null;

    /*Get the database user and password from config file*/
    @Override
    public void init() throws ServletException {

        user = getInitParameter("dbUser");
        pw_con = getInitParameter("dbPassword");
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        String email = request.getParameter("email");
        User u = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            throw new AssertionError(e);
        }
        String connectionStr = "jdbc:mysql://localhost/DisasterAssessment";

        try {
            con = (Connection) DriverManager.getConnection(connectionStr, user, pw_con);
            u = User.lookup(email, con);
        } catch (SQLException ex) {
            Logger.getLogger(ForgotPassword.class.getName()).log(Level.SEVERE, null, ex);
        }

        String message;
        if (u != null) {

            String newPassword = genNewPassword();
            u.setPassword(newPassword);
            try {
                u.update(con, u.getUserId());
            } catch (SQLException ex) {
                System.out.println("failed to update the new password.");
            }
            sendEmail(email, newPassword);
            message = "Your new password has been sent to your email.";

        } else {
            message = "Your email doesn't exsit.";
        }
        request.setAttribute("RegisterMessage", message);
        RequestDispatcher red = getServletContext().getRequestDispatcher("/index.jsp");
        red.forward(request, response);

    }

    private void sendEmail(String toAddress, String newPassword) {
        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.socketFactory.port", "465");
        props.put("mail.smtp.socketFactory.class",
                "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.port", "465");

        Session session = Session.getInstance(props,
                new javax.mail.Authenticator() {

                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication("disasterassessment", "disasterassessment");
                    }
                });

        try {
            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("account_update@redcross.org"));
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse(toAddress));
            message.setSubject("Disaster Assessment App Password Assistance");
            message.setText("We received a request to reset the password associated with this e-mail address"
                    + "\n\n Your new password is: " + newPassword
                    + "\n\n Please log in using the new password and reset it as soon as possible. ");

            Transport.send(message);

            System.out.println("Done");

        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }
    }

    private String genNewPassword() {
        char[] symbols = new char[36];
        char[] buf = new char[8];
        Random random = new Random();

        for (int idx = 0; idx < 10; ++idx) {
            symbols[idx] = (char) ('0' + idx);
        }
        for (int idx = 10; idx < 36; ++idx) {
            symbols[idx] = (char) ('a' + idx - 10);
        }

        for (int idx = 0; idx < buf.length; ++idx) {
            buf[idx] = symbols[random.nextInt(symbols.length)];
        }
        return new String(buf);
    }
}