package com.nilhcem.fakesmtp.gui.tab;

 import ch.qos.logback.classic.spi.ILoggingEvent;

 import ch.qos.logback.core.spi.AppenderAttachable;

 import com.nilhcem.fakesmtp.core.Configuration;

 import com.nilhcem.fakesmtp.gui.info.ClearAllButton;

 import com.nilhcem.fakesmtp.log.SMTPLogsAppender;

 import com.nilhcem.fakesmtp.log.SMTPLogsObservable;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import javax.swing.JScrollPane;

 import javax.swing.JTextArea;

 import java.text.SimpleDateFormat;

 import java.util.Date;

 import java.util.Observable;

 import java.util.Observer;

 /**

  * Scrolled text area where will be displayed the SMTP logs.

  *

  * @author Nilhcem

  * @since 1.0

  */

 public final class LogsPane implements Observer {

         private final JScrollPane logsPane = new JScrollPane();

         private final SimpleDateFormat dateFormat = new SimpleDateFormat("hh:mm:ss a");

         private final JTextArea logsArea = new JTextArea();

         /**

          * Creates the text area, sets it as non-editable and sets an observer to intercept logs.

          */

         public LogsPane() {

                 logsArea.setEditable(false);

                 logsPane.getViewport().add(logsArea, null);

                 addObserverToSmtpLogAppender();

         }

         /**

          * Returns the JScrollPane object.

          *

          * @return the JScrollPane object.

          */

         public JScrollPane get() {

                 return logsPane;

         }

         /**

          * Adds this object to the SMTP logs appender observable, to intercept logs.

          * <p>

          * The goal is to be informed when the log appender will received some debug SMTP logs.<br>

          * When a log is written, the appender will notify this class which will display it in the text area.

          * </p>

          */

         private void addObserverToSmtpLogAppender() {

                 Logger smtpLogger = LoggerFactory.getLogger(org.subethamail.smtp.server.Session.class);

                 String appenderName = Configuration.INSTANCE.get("logback.appender.name");

                 @SuppressWarnings("unchecked")

                 SMTPLogsAppender<ILoggingEvent> appender = (SMTPLogsAppender<ILoggingEvent>)

                         ((AppenderAttachable<ILoggingEvent>) smtpLogger).getAppender(appenderName);

                 if (appender == null) {

                         LoggerFactory.getLogger(LogsPane.class).error("Can't find logger: {}", appenderName);

                 } else {

                         appender.getObservable().addObserver(this);

                 }

         }

         /**

          * Updates the content of the text area.

          * <p>

          * This method will be called by an observable element.

      * </p>

          * <ul>

          *   <li>If the observable is a {@link SMTPLogsObservable} object, the text area will display the received log.</li>

          *   <li>If the observable is a {@link ClearAllButton} object, the text area will be cleared.</li>

          * </ul>

          *

          * @param o the observable element which will notify this class.

          * @param log optional parameter (a {@code String} object, when the observable is a {@code SMTPLogsObservable} object, which will contain the log).

          */

         @Override

         public void update(Observable o, Object log) {

                 if (o instanceof SMTPLogsObservable) {

                         // Update and scroll pane to the bottom

                         logsArea.append(String.format("%s - %s%n", dateFormat.format(new Date()), log));

                         logsArea.setCaretPosition(logsArea.getText().length());

                 } else if (o instanceof ClearAllButton) {

                         // Remove text

                         logsArea.setText("");

                 }

         }

 }