/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.mail2.javax;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.io.BufferedOutputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.File;
  import java.io.IOException;
  import java.net.URL;
  import java.util.Date;
  import java.util.Enumeration;
  import java.util.List;
  
  import javax.activation.DataHandler;
  import javax.mail.Header;
  import javax.mail.MessagingException;
  import javax.mail.Multipart;
  import javax.mail.internet.InternetAddress;
  import javax.mail.internet.MimeMessage;
  
  import org.apache.commons.mail2.javax.settings.EmailConfiguration;
  import org.apache.commons.mail2.javax.util.MimeMessageUtils;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeEach;
  import org.mockito.Mockito;
  import org.subethamail.wiser.Wiser;
  import org.subethamail.wiser.WiserMessage;
  
  /**
   * Base test case for Email test classes.
   */
  public abstract class AbstractEmailTest {
      /** Padding at end of body added by wiser/send */
      public static final int BODY_END_PAD = 3;
  
      /** Padding at start of body added by wiser/send */
      public static final int BODY_START_PAD = 2;
  
      /** Line separator in email messages */
      private static final String LINE_SEPARATOR = "\r\n";
  
      /** Default port */
      private static int mailServerPort = 2500;
  
      /** Counter for creating a file name */
      private static int fileNameCounter;
  
      /** The fake Wiser email server */
      protected Wiser fakeMailServer;
  
      /** Mail server used for testing */
      protected String strTestMailServer = "localhost";
  
      /** From address for the test email */
      protected String strTestMailFrom = "test_from@apache.org";
  
      /** Destination address for the test email */
      protected String strTestMailTo = "test_to@apache.org";
  
      /** Mailserver username (set if needed) */
      protected String strTestUser = "user";
  
      /** Mailserver strTestPasswd (set if needed) */
      protected String strTestPasswd = "password";
  
      /** URL to used to test URL attachments (Must be valid) */
      protected String strTestURL = EmailConfiguration.TEST_URL;
  
      /** Test characters acceptable to email */
      protected String[] testCharsValid = { " ", "a", "A", "\uc5ec", "0123456789", "012345678901234567890" };
  
      /** Test characters not acceptable to email */
      protected String[] endOfLineCombinations = { "\n", "\r", "\r\n", "\n\r", };
  
      /** Array of test strings */
      protected String[] testCharsNotValid = { "", null };
  
      /** Where to save email output **/
      private File emailOutputDir;
  
     /**
      * Create a mocked URL object which always throws an IOException when the openStream() method is called.
      * <p>
      * Several ISPs do resolve invalid URLs like {@code https://example.invalid} to some error page causing tests to fail otherwise.
      * </p>
      *
      * @return an invalid URL
      */
     @SuppressWarnings("resource") // openStream() returns null.
     protected URL createInvalidURL() throws Exception {
         URL url = new URL("http://example.invalid");
         url = Mockito.spy(url);
         Mockito.doThrow(new IOException("Mocked IOException")).when(url).openStream();
         return url;
     }
 
     /**
      * Initializes the stub mail server. Fails if the server cannot be proven to have started. If the server is already started, this method returns without
      * changing the state of the server.
      */
     public void getMailServer() {
         if (fakeMailServer == null || isMailServerStopped(fakeMailServer)) {
             mailServerPort++;
 
             fakeMailServer = new Wiser();
             fakeMailServer.setPort(getMailServerPort());
             fakeMailServer.start();
 
             assertFalse(isMailServerStopped(fakeMailServer), "fake mail server didn't start");
 
             final Date dtStartWait = new Date();
             while (isMailServerStopped(fakeMailServer)) {
                 // test for connected
                 if (fakeMailServer != null && !isMailServerStopped(fakeMailServer)) {
                     break;
                 }
 
                 // test for timeout
                 if (dtStartWait.getTime() + EmailConfiguration.TIME_OUT <= new Date().getTime()) {
                     fail("Mail server failed to start");
                 }
             }
         }
     }
 
     /**
      * Gets the mail server port.
      *
      * @return the port the server is running on.
      */
     protected int getMailServerPort() {
         return mailServerPort;
     }
 
     /**
      * @param intMsgNo the message to retrieve
      * @return message as string
      */
     public String getMessageAsString(final int intMsgNo) {
         final List<?> receivedMessages = fakeMailServer.getMessages();
         assertTrue(receivedMessages.size() >= intMsgNo, "mail server didn't get enough messages");
 
         final WiserMessage emailMessage = (WiserMessage) receivedMessages.get(intMsgNo);
 
         if (emailMessage != null) {
             try {
                 return serializeEmailMessage(emailMessage);
             } catch (final Exception e) {
                 // ignore, since the test will fail on an empty string return
             }
         }
         fail("Message not found");
         return "";
     }
 
     /**
      * Returns a string representation of the message body. If the message body cannot be read, an empty string is returned.
      *
      * @param wiserMessage The wiser message from which to extract the message body
      * @return The string representation of the message body
      * @throws IOException Thrown while serializing the body from {@link DataHandler#writeTo(java.io.OutputStream)}.
      */
     private String getMessageBody(final WiserMessage wiserMessage) throws IOException {
         if (wiserMessage == null) {
             return "";
         }
 
         byte[] messageBody = null;
 
         try {
             final MimeMessage message = wiserMessage.getMimeMessage();
             messageBody = getMessageBodyBytes(message);
         } catch (final MessagingException e) {
             // Thrown while getting the body content from
             // {@link MimeMessage#getDataHandler()}
             final IllegalStateException rethrow = new IllegalStateException("couldn't process MimeMessage from WiserMessage in getMessageBody()");
             rethrow.initCause(e);
             throw rethrow;
         }
 
         return messageBody != null ? new String(messageBody).intern() : "";
     }
 
     /**
      * Gets the byte making up the body of the message.
      *
      * @param mimeMessage The mime message from which to extract the body.
      * @return A byte array representing the message body
      * @throws IOException        Thrown while serializing the body from {@link DataHandler#writeTo(java.io.OutputStream)}.
      * @throws MessagingException Thrown while getting the body content from {@link MimeMessage#getDataHandler()}
      */
     private byte[] getMessageBodyBytes(final MimeMessage mimeMessage) throws IOException, MessagingException {
         final DataHandler dataHandler = mimeMessage.getDataHandler();
         final ByteArrayOutputStream byteArrayOutStream = new ByteArrayOutputStream();
         final BufferedOutputStream buffOs = new BufferedOutputStream(byteArrayOutStream);
         dataHandler.writeTo(buffOs);
         buffOs.flush();
 
         return byteArrayOutStream.toByteArray();
     }
 
     /**
      * Checks if an email server is running at the address stored in the {@code fakeMailServer}.
      *
      * @param fakeMailServer The server from which the address is picked up.
      * @return {@code true} if the server claims to be running
      */
     protected boolean isMailServerStopped(final Wiser fakeMailServer) {
         return !fakeMailServer.getServer().isRunning();
     }
 
     /**
      * Safe a mail to a file using a more or less unique file name.
      *
      * @param email email
      * @throws IOException        writing the email failed
      * @throws MessagingException writing the email failed
      */
     protected void saveEmailToFile(final WiserMessage email) throws IOException, MessagingException {
         final int currCounter = fileNameCounter++ % 10;
         final String emailFileName = "email" + new Date().getTime() + "-" + currCounter + ".eml";
         final File emailFile = new File(emailOutputDir, emailFileName);
         MimeMessageUtils.writeMimeMessage(email.getMimeMessage(), emailFile);
     }
 
     /**
      * Serializes the {@link MimeMessage} from the {@code WiserMessage} passed in. The headers are serialized first followed by the message body.
      *
      * @param wiserMessage The {@code WiserMessage} to serialize.
      * @return The string format of the message.
      * @throws MessagingException
      * @throws IOException        Thrown while serializing the body from {@link DataHandler#writeTo(java.io.OutputStream)}.
      * @throws MessagingException Thrown while getting the body content from {@link MimeMessage#getDataHandler()}
      */
     private String serializeEmailMessage(final WiserMessage wiserMessage) throws MessagingException, IOException {
         if (wiserMessage == null) {
             return "";
         }
 
         final StringBuilder serializedEmail = new StringBuilder();
         final MimeMessage message = wiserMessage.getMimeMessage();
 
         // Serialize the headers
         for (final Enumeration<?> headers = message.getAllHeaders(); headers.hasMoreElements();) {
             final Header header = (Header) headers.nextElement();
             serializedEmail.append(header.getName());
             serializedEmail.append(": ");
             serializedEmail.append(header.getValue());
             serializedEmail.append(LINE_SEPARATOR);
         }
 
         // Serialize the body
         final byte[] messageBody = getMessageBodyBytes(message);
 
         serializedEmail.append(LINE_SEPARATOR);
         serializedEmail.append(messageBody);
         serializedEmail.append(LINE_SEPARATOR);
 
         return serializedEmail.toString();
     }
 
     @BeforeEach
     public void setUpAbstractEmailTest() {
         emailOutputDir = new File("target/test-emails");
         if (!emailOutputDir.exists()) {
             emailOutputDir.mkdirs();
         }
     }
 
     protected void stopServer() {
         if (fakeMailServer != null) {
             fakeMailServer.stop();
         }
     }
 
     @AfterEach
     public void tearDownEmailTest() {
         // stop the fake email server (if started)
         if (fakeMailServer != null && !isMailServerStopped(fakeMailServer)) {
             fakeMailServer.stop();
             assertTrue(isMailServerStopped(fakeMailServer), "Mail server didn't stop");
         }
 
         fakeMailServer = null;
     }
 
     /**
      * Validate the message was sent properly
      *
      * @param mailServer     reference to the fake mail server
      * @param strSubject     expected subject
      * @param fromAdd        expected from address
      * @param toAdd          list of expected to addresses
      * @param ccAdd          list of expected cc addresses
      * @param bccAdd         list of expected bcc addresses
      * @param boolSaveToFile true will output to file, false doesn't
      * @return WiserMessage email to check
      * @throws IOException Exception
      */
     protected WiserMessage validateSend(final Wiser mailServer, final String strSubject, final InternetAddress fromAdd, final List<InternetAddress> toAdd,
             final List<InternetAddress> ccAdd, final List<InternetAddress> bccAdd, final boolean boolSaveToFile) throws IOException {
         assertTrue(mailServer.getMessages().size() == 1, "mail server doesn't contain expected message");
         final WiserMessage emailMessage = mailServer.getMessages().get(0);
 
         if (boolSaveToFile) {
             try {
                 saveEmailToFile(emailMessage);
             } catch (final MessagingException e) {
                 final IllegalStateException rethrow = new IllegalStateException("caught MessagingException during saving the email");
                 rethrow.initCause(e);
                 throw rethrow;
             }
         }
 
         try {
             // get the MimeMessage
             final MimeMessage mimeMessage = emailMessage.getMimeMessage();
 
             // test subject
             assertEquals(strSubject, mimeMessage.getHeader("Subject", null), "got wrong subject from mail");
 
             // test from address
             assertEquals(fromAdd.toString(), mimeMessage.getHeader("From", null), "got wrong From: address from mail");
 
             // test to address
             assertTrue(toAdd.toString().contains(mimeMessage.getHeader("To", null)), "got wrong To: address from mail");
 
             // test cc address
             if (!ccAdd.isEmpty()) {
                 assertTrue(ccAdd.toString().contains(mimeMessage.getHeader("Cc", null)), "got wrong Cc: address from mail");
             }
 
             // test bcc address
             if (!bccAdd.isEmpty()) {
                 assertTrue(bccAdd.toString().contains(mimeMessage.getHeader("Bcc", null)), "got wrong Bcc: address from mail");
             }
         } catch (final MessagingException e) {
             final IllegalStateException rethrow = new IllegalStateException("caught MessagingException in validateSend()");
             rethrow.initCause(e);
             throw rethrow;
         }
 
         return emailMessage;
     }
 
     /**
      * Validate the message was sent properly
      *
      * @param mailServer     reference to the fake mail server
      * @param strSubject     expected subject
      * @param content        the expected message content
      * @param fromAdd        expected from address
      * @param toAdd          list of expected to addresses
      * @param ccAdd          list of expected cc addresses
      * @param bccAdd         list of expected bcc addresses
      * @param boolSaveToFile true will output to file, false doesn't
      * @throws IOException Exception
      */
     protected void validateSend(final Wiser mailServer, final String strSubject, final Multipart content, final InternetAddress fromAdd,
             final List<InternetAddress> toAdd, final List<InternetAddress> ccAdd, final List<InternetAddress> bccAdd, final boolean boolSaveToFile)
             throws IOException {
         // test other properties
         final WiserMessage emailMessage = validateSend(mailServer, strSubject, fromAdd, toAdd, ccAdd, bccAdd, boolSaveToFile);
 
         // test message content
 
         // get sent email content
         final String strSentContent = content.getContentType();
         // get received email content (chop off the auto-added \n
         // and -- (front and end)
         final String emailMessageBody = getMessageBody(emailMessage);
         final String strMessageBody = emailMessageBody.substring(AbstractEmailTest.BODY_START_PAD, emailMessageBody.length() - AbstractEmailTest.BODY_END_PAD);
         assertTrue(strMessageBody.contains(strSentContent), "didn't find expected content type in message body");
     }
 
     /**
      * Validate the message was sent properly
      *
      * @param mailServer     reference to the fake mail server
      * @param strSubject     expected subject
      * @param strMessage     the expected message as a string
      * @param fromAdd        expected from address
      * @param toAdd          list of expected to addresses
      * @param ccAdd          list of expected cc addresses
      * @param bccAdd         list of expected bcc addresses
      * @param boolSaveToFile true will output to file, false doesn't
      * @throws IOException Exception
      */
     protected void validateSend(final Wiser mailServer, final String strSubject, final String strMessage, final InternetAddress fromAdd,
             final List<InternetAddress> toAdd, final List<InternetAddress> ccAdd, final List<InternetAddress> bccAdd, final boolean boolSaveToFile)
             throws IOException {
         // test other properties
         final WiserMessage emailMessage = validateSend(mailServer, strSubject, fromAdd, toAdd, ccAdd, bccAdd, true);
 
         // test message content
         assertTrue(getMessageBody(emailMessage).contains(strMessage), "didn't find expected message content in message body");
     }
 }