Save important flag to IMAP if permflags enabled

Signed-off-by: Anna Larch <anna@nextcloud.com>

4 files changed, 62 insertions, 5 deletions

diff --git a/lib/Db/MessageMapper.php b/lib/Db/MessageMapper.php
index e83d08961..81f1967a7 100644
--- a/lib/Db/MessageMapper.php
+++ b/lib/Db/MessageMapper.php
@@ -333,6 +333,7 @@ class MessageMapper extends QBMapper {
 			->set('flag_junk', $query->createParameter('flag_junk'))
 			->set('flag_notjunk', $query->createParameter('flag_notjunk'))
 			->set('flag_mdnsent', $query->createParameter('flag_mdnsent'))
+			->set('flag_important', $query->createParameter('flag_important'))
 			->set('updated_at', $query->createNamedParameter($this->timeFactory->getTime()))
 			->where($query->expr()->andX(
 				$query->expr()->eq('uid', $query->createParameter('uid')),
@@ -356,6 +357,7 @@ class MessageMapper extends QBMapper {
 			$query->setParameter('flag_junk', $message->getFlagJunk(), IQueryBuilder::PARAM_BOOL);
 			$query->setParameter('flag_notjunk', $message->getFlagNotjunk(), IQueryBuilder::PARAM_BOOL);
 			$query->setParameter('flag_mdnsent', $message->getFlagMdnsent(), IQueryBuilder::PARAM_BOOL);
+			$query->setParameter('flag_important', $message->getFlagImportant(), IQueryBuilder::PARAM_BOOL);
 
 			$query->execute();
 		}
diff --git a/lib/Listener/NewMessageClassificationListener.php b/lib/Listener/NewMessageClassificationListener.php
index 365251883..56585730c 100644
--- a/lib/Listener/NewMessageClassificationListener.php
+++ b/lib/Listener/NewMessageClassificationListener.php
@@ -67,11 +67,16 @@ class NewMessageClassificationListener implements IEventListener {
 			}
 		}
 
+		// if the message is already flagged as important, we won't classify it again.
+		$messages = array_filter($event->getMessages(), function ($message) {
+			return ($message->getFlagImportant() === false);
+		});
+
 		try {
 			$predictions = $this->classifier->classifyImportance(
 				$event->getAccount(),
 				$event->getMailbox(),
-				$event->getMessages()
+				$messages
 			);
 
 			foreach ($event->getMessages() as $message) {
diff --git a/lib/Model/IMAPMessage.php b/lib/Model/IMAPMessage.php
index 46f00da08..bd8437e72 100644
--- a/lib/Model/IMAPMessage.php
+++ b/lib/Model/IMAPMessage.php
@@ -129,6 +129,7 @@ class IMAPMessage implements IMessage, JsonSerializable {
 	}
 
 	/**
+	 * @deprecated  Seems unused
 	 * @return array
 	 */
 	public function getFlags(): array {
@@ -142,10 +143,12 @@ class IMAPMessage implements IMessage, JsonSerializable {
 			'forwarded' => in_array(Horde_Imap_Client::FLAG_FORWARDED, $flags),
 			'hasAttachments' => $this->hasAttachments($this->fetch->getStructure()),
 			'mdnsent' => in_array(Horde_Imap_Client::FLAG_MDNSENT, $flags, true),
+			'important' => in_array('$important', $flags, true)
 		];
 	}
 
 	/**
+	 * @deprecated  Seems unused
 	 * @param string[] $flags
 	 *
 	 * @throws Exception
@@ -691,7 +694,7 @@ class IMAPMessage implements IMessage, JsonSerializable {
 			in_array('junk', $flags, true)
 		);
 		$msg->setFlagNotjunk(in_array(Horde_Imap_Client::FLAG_NOTJUNK, $flags, true));
-		$msg->setFlagImportant(false);
+		$msg->setFlagImportant(in_array('$important', $flags, true));
 		$msg->setFlagAttachments(false);
 		$msg->setFlagMdnsent(in_array(Horde_Imap_Client::FLAG_MDNSENT, $flags, true));
 
diff --git a/lib/Service/MailManager.php b/lib/Service/MailManager.php
index 96c12b5b0..d37278477 100644
--- a/lib/Service/MailManager.php
+++ b/lib/Service/MailManager.php
@@ -26,6 +26,7 @@ namespace OCA\Mail\Service;
 use Horde_Imap_Client;
 use Horde_Imap_Client_Exception;
 use Horde_Imap_Client_Exception_NoSupportExtension;
+use Horde_Imap_Client_Socket;
 use OCA\Mail\Account;
 use OCA\Mail\Contracts\IMailManager;
 use OCA\Mail\Db\Mailbox;
@@ -386,10 +387,13 @@ class MailManager implements IMailManager {
 		}
 
 		// Only send system flags to the IMAP server as other flags might not be supported
-		$imapFlags = self::ALLOWED_FLAGS[$flag] ?? [];
+		$imapFlags = $this->filterFlags($account, $flag, $mailbox);
 		try {
 			foreach ($imapFlags as $imapFlag) {
-				if ($value) {
+				if (empty($imapFlag) === true) {
+					continue;
+				}
+				if ($value === true) {
 					$this->imapMessageMapper->addFlag($client, $mb, $uid, $imapFlag);
 				} else {
 					$this->imapMessageMapper->removeFlag($client, $mb, $uid, $imapFlag);
@@ -509,7 +513,50 @@ class MailManager implements IMailManager {
 	 * @param Message $message
 	 * @return array[]
 	 */
-	public function getMailAttachments(Account $account, Mailbox $mailbox, Message $message) : array {
+	public function getMailAttachments(Account $account, Mailbox $mailbox, Message $message): array {
 		return $this->imapMessageMapper->getAttachments($this->imapClientFactory->getClient($account), $mailbox->getName(), $message->getUid());
 	}
+
+	/**
+	 * Filter out IMAP flags that aren't supported by the client server
+	 *
+	 * @param Horde_Imap_Client_Socket $client
+	 * @param string $flag
+	 * @param string $mailbox
+	 * @return array
+	 */
+	public function filterFlags(Account $account, string $flag, string $mailbox): array {
+		// check for RFC server flags
+		if (array_key_exists($flag, self::ALLOWED_FLAGS) === true) {
+			return self::ALLOWED_FLAGS[$flag];
+		}
+
+		// Only allow flag setting if IMAP supports Permaflags
+		// @TODO check if there are length & char limits on permflags
+		if ($this->isPermflagsEnabled($account, $mailbox) === true) {
+			return ["$" . $flag];
+		}
+		return [];
+	}
+
+	/**
+	 * Check IMAP server for support for PERMANENTFLAGS
+	 *
+	 * @param Account $account
+	 * @param string $mailbox
+	 * @return boolean
+	 */
+	public function isPermflagsEnabled(Account $account, string $mailbox): bool {
+		$client = $this->imapClientFactory->getClient($account);
+		try {
+			$capabilities = $client->status($mailbox, Horde_Imap_Client::STATUS_PERMFLAGS);
+		} catch (Horde_Imap_Client_Exception $e) {
+			throw new ServiceException(
+				"Could not get message flag options from IMAP: " . $e->getMessage(),
+				(int) $e->getCode(),
+				$e
+			);
+		}
+		return (is_array($capabilities) === true && array_key_exists('permflags', $capabilities) === true && in_array("\*", $capabilities['permflags'], true) === true);
+	}
 }