Rework the routing

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

29 files changed, 731 insertions, 418 deletions

diff --git a/lib/Attachment.php b/lib/Attachment.php
index 33acaace9..1770587be 100644
--- a/lib/Attachment.php
+++ b/lib/Attachment.php
@@ -32,13 +32,13 @@ class Attachment {
 	/**
 	 * @param \Horde_Imap_Client_Socket $conn
 	 * @param \Horde_Imap_Client_Mailbox $mailBox
-	 * @param int $messageId
+	 * @param int $messageUid
 	 * @param string $attachmentId
 	 */
-	public function __construct($conn, $mailBox, $messageId, $attachmentId) {
+	public function __construct($conn, $mailBox, $messageUid, $attachmentId) {
 		$this->conn = $conn;
 		$this->mailBox = $mailBox;
-		$this->messageId = $messageId;
+		$this->messageUid = $messageUid;
 		$this->attachmentId = $attachmentId;
 
 		$this->load();
@@ -53,7 +53,7 @@ class Attachment {
 	 * @var \Horde_Imap_Client_Mailbox
 	 */
 	private $mailBox;
-	private $messageId;
+	private $messageUid;
 	private $attachmentId;
 
 	/**
@@ -67,13 +67,13 @@ class Attachment {
 		$fetch_query->mimeHeader($this->attachmentId);
 
 		// $list is an array of Horde_Imap_Client_Data_Fetch objects.
-		$ids = new \Horde_Imap_Client_Ids($this->messageId);
+		$ids = new \Horde_Imap_Client_Ids($this->messageUid);
 		$headers = $this->conn->fetch($this->mailBox, $fetch_query, ['ids' => $ids]);
 		/** @var $fetch Horde_Imap_Client_Data_Fetch */
-		if (!isset($headers[$this->messageId])) {
+		if (!isset($headers[$this->messageUid])) {
 			throw new DoesNotExistException('Unable to load the attachment.');
 		}
-		$fetch = $headers[$this->messageId];
+		$fetch = $headers[$this->messageUid];
 		/** @var \Horde_Mime_Headers $mimeHeaders */
 		$mimeHeaders = $fetch->getMimeHeader($this->attachmentId, Horde_Imap_Client_Data_Fetch::HEADER_PARSE);
 
diff --git a/lib/Contracts/IMailManager.php b/lib/Contracts/IMailManager.php
index 553aea52b..212aee8a8 100644
--- a/lib/Contracts/IMailManager.php
+++ b/lib/Contracts/IMailManager.php
@@ -25,16 +25,28 @@ namespace OCA\Mail\Contracts;
 
 use OCA\Mail\Account;
 use OCA\Mail\Db\Mailbox;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Exception\ClientException;
 use OCA\Mail\Exception\ServiceException;
 use OCA\Mail\Folder;
 use OCA\Mail\IMAP\FolderStats;
 use OCA\Mail\Model\IMAPMessage;
 use OCA\Mail\Service\Quota;
+use OCP\AppFramework\Db\DoesNotExistException;
 
 interface IMailManager {
 
 	/**
+	 * @param string $uid
+	 * @param int $id
+	 *
+	 * @return Mailbox
+	 *
+	 * @throws DoesNotExistException
+	 */
+	public function getMailbox(string $uid, int $id): Mailbox;
+
+	/**
 	 * @param Account $account
 	 *
 	 * @return Mailbox[]
@@ -47,44 +59,63 @@ interface IMailManager {
 	 * @param Account $account
 	 * @param string $name
 	 *
-	 * @return Folder
+	 * @return Mailbox
 	 *
 	 * @throws ServiceException
 	 */
-	public function createFolder(Account $account, string $name): Folder;
+	public function createMailbox(Account $account, string $name): Mailbox;
 
 	/**
 	 * @param Account $account
-	 * @param string $folderId
+	 * @param Mailbox $mailbox
 	 *
 	 * @return FolderStats
+	 */
+	public function getMailboxStats(Account $account, Mailbox $mailbox): FolderStats;
+
+	/**
+	 * @param Mailbox $mailbox
+	 * @param $uid
 	 *
-	 * @throws ServiceException
+	 * @return int|null
+	 */
+	public function getMessageIdForUid(Mailbox $mailbox, $uid): ?int;
+
+	/**
+	 * @param string $uid
+	 * @param int $id
+	 *
+	 * @return Mailbox
+	 *
+	 * @throws ClientException
 	 */
-	public function getFolderStats(Account $account, string $folderId): FolderStats;
+	public function getMessage(string $uid, int $id): Message;
 
 	/**
 	 * @param Account $account
 	 * @param string $mb
-	 * @param int $id
+	 * @param int $uid
 	 *
 	 * @return string
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function getSource(Account $account, string $mb, int $id): string;
+	public function getSource(Account $account, string $mb, int $uid): ?string;
 
 	/**
 	 * @param Account $account
-	 * @param string $mailbox
-	 * @param int $id
+	 * @param Mailbox $mailbox
+	 * @param int $uid
 	 * @param bool $loadBody
 	 *
 	 * @return IMAPMessage
 	 *
 	 * @throws ServiceException
 	 */
-	public function getMessage(Account $account, string $mailbox, int $id, bool $loadBody = false): IMAPMessage;
+	public function getImapMessage(Account $account,
+								   Mailbox $mailbox,
+								   int $uid,
+								   bool $loadBody = false): IMAPMessage;
 
 	/**
 	 * @param Account $account
@@ -97,14 +128,17 @@ interface IMailManager {
 	/**
 	 * @param Account $sourceAccount
 	 * @param string $sourceFolderId
-	 * @param int $messageId
+	 * @param int $uid
 	 * @param Account $destinationAccount
 	 * @param string $destFolderId
 	 *
 	 * @throws ServiceException
 	 */
-	public function moveMessage(Account $sourceAccount, string $sourceFolderId, int $messageId,
-								Account $destinationAccount, string $destFolderId);
+	public function moveMessage(Account $sourceAccount,
+								string $sourceFolderId,
+								int $uid,
+								Account $destinationAccount,
+								string $destFolderId);
 
 	/**
 	 * @param Account $account
@@ -119,11 +153,9 @@ interface IMailManager {
 	 * Mark all messages of a folder as read
 	 *
 	 * @param Account $account
-	 * @param string $folderId
-	 *
-	 * @throws ServiceException
+	 * @param Mailbox $mailbox
 	 */
-	public function markFolderAsRead(Account $account, string $folderId): void;
+	public function markFolderAsRead(Account $account, Mailbox $mailbox): void;
 
 	/**
 	 * @param Account $account
@@ -146,9 +178,9 @@ interface IMailManager {
 
 	/**
 	 * @param Account $account
-	 * @param string $folderId
+	 * @param Mailbox $mailbox
 	 *
 	 * @throws ServiceException
 	 */
-	public function deleteMailbox(Account $account, string $folderId): void;
+	public function deleteMailbox(Account $account, Mailbox $mailbox): void;
 }
diff --git a/lib/Contracts/IMailSearch.php b/lib/Contracts/IMailSearch.php
index 9487334b2..c751e2c53 100644
--- a/lib/Contracts/IMailSearch.php
+++ b/lib/Contracts/IMailSearch.php
@@ -26,6 +26,7 @@ declare(strict_types=1);
 namespace OCA\Mail\Contracts;
 
 use OCA\Mail\Account;
+use OCA\Mail\Db\Mailbox;
 use OCA\Mail\Db\Message;
 use OCA\Mail\Exception\ClientException;
 use OCA\Mail\Exception\ServiceException;
@@ -43,18 +44,25 @@ interface IMailSearch {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function findMessage(Account $account, string $mailboxName, int $uid): Message;
+	public function findMessage(Account $account,
+								Mailbox $mailbox,
+								Message $message): Message;
 
 	/**
 	 * @param Account $account
-	 * @param string $mailboxName
+	 * @param Mailbox $mailbox
 	 * @param string|null $filter
 	 * @param int|null $cursor
+	 * @param int|null $limit
 	 *
 	 * @return Message[]
 	 *
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function findMessages(Account $account, string $mailboxName, ?string $filter, ?int $cursor, ?int $limit): array;
+	public function findMessages(Account $account,
+								 Mailbox $mailbox,
+								 ?string $filter,
+								 ?int $cursor,
+								 ?int $limit): array;
 }
diff --git a/lib/Contracts/IMailTransmission.php b/lib/Contracts/IMailTransmission.php
index ff1d04138..d4e4c3c57 100644
--- a/lib/Contracts/IMailTransmission.php
+++ b/lib/Contracts/IMailTransmission.php
@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace OCA\Mail\Contracts;
 
 use OCA\Mail\Db\Alias;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Exception\ServiceException;
 use OCA\Mail\Model\NewMessageData;
 use OCA\Mail\Model\RepliedMessageData;
@@ -33,27 +34,27 @@ interface IMailTransmission {
 	/**
 	 * Send a new message or reply to an existing one
 	 *
-	 * @param string $userId
 	 * @param NewMessageData $message
-	 * @param RepliedMessageData $reply
+	 * @param RepliedMessageData|null $reply
 	 * @param Alias|null $alias
+	 * @param Message|null $draft
 	 *
 	 * @throws ServiceException
 	 */
 	public function sendMessage(NewMessageData $message,
 								RepliedMessageData $reply = null,
 								Alias $alias = null,
-								int $draftUID = null);
+								Message $draft = null);
 
 	/**
 	 * Save a message draft
 	 *
 	 * @param NewMessageData $message
-	 * @param int $draftUID
+	 * @param Message|null $previousDraft
 	 *
-	 * @return int
+	 * @return array
 	 *
 	 * @throws ServiceException
 	 */
-	public function saveDraft(NewMessageData $message, int $draftUID = null): int;
+	public function saveDraft(NewMessageData $message, Message $previousDraft = null): array;
 }
diff --git a/lib/Controller/AccountsController.php b/lib/Controller/AccountsController.php
index e5c8a94bb..94221eb09 100644
--- a/lib/Controller/AccountsController.php
+++ b/lib/Controller/AccountsController.php
@@ -30,8 +30,10 @@ declare(strict_types=1);
 namespace OCA\Mail\Controller;
 
 use Exception;
+use Horde_Imap_Client;
 use OCA\Mail\Contracts\IMailManager;
 use OCA\Mail\Contracts\IMailTransmission;
+use OCA\Mail\Db\Mailbox;
 use OCA\Mail\Exception\ClientException;
 use OCA\Mail\Exception\ServiceException;
 use OCA\Mail\Http\JsonResponse as MailJsonResponse;
@@ -41,6 +43,7 @@ use OCA\Mail\Service\AccountService;
 use OCA\Mail\Service\AliasesService;
 use OCA\Mail\Service\GroupsIntegration;
 use OCA\Mail\Service\SetupService;
+use OCA\Mail\Service\Sync\SyncService;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
@@ -77,17 +80,37 @@ class AccountsController extends Controller {
 	/** @var IMailManager */
 	private $mailManager;
 
+	/** @var SyncService */
+	private $syncService;
+
+	/**
+	 * AccountsController constructor.
+	 *
+	 * @param string $appName
+	 * @param IRequest $request
+	 * @param AccountService $accountService
+	 * @param GroupsIntegration $groupsIntegration
+	 * @param $UserId
+	 * @param ILogger $logger
+	 * @param IL10N $l10n
+	 * @param AliasesService $aliasesService
+	 * @param IMailTransmission $mailTransmission
+	 * @param SetupService $setup
+	 * @param IMailManager $mailManager
+	 * @param SyncService $syncService
+	 */
 	public function __construct(string $appName,
-								IRequest $request,
-								AccountService $accountService,
-								GroupsIntegration $groupsIntegration,
-								$UserId,
-								ILogger $logger,
-								IL10N $l10n,
-								AliasesService $aliasesService,
-								IMailTransmission $mailTransmission,
-								SetupService $setup,
-								IMailManager $mailManager
+								   IRequest $request,
+								   AccountService $accountService,
+								   GroupsIntegration $groupsIntegration,
+								   $UserId,
+								   ILogger $logger,
+								   IL10N $l10n,
+								   AliasesService $aliasesService,
+								   IMailTransmission $mailTransmission,
+								   SetupService $setup,
+								   IMailManager $mailManager,
+								   SyncService $syncService
 	) {
 		parent::__construct($appName, $request);
 		$this->accountService = $accountService;
@@ -99,6 +122,7 @@ class AccountsController extends Controller {
 		$this->mailTransmission = $mailTransmission;
 		$this->setup = $setup;
 		$this->mailManager = $mailManager;
+		$this->syncService = $syncService;
 	}
 
 	/**
@@ -123,13 +147,13 @@ class AccountsController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
+	 * @param int $id
 	 *
 	 * @return JSONResponse
 	 * @throws ClientException
 	 */
-	public function show($accountId): JSONResponse {
-		return new JSONResponse($this->accountService->find($this->currentUserId, $accountId));
+	public function show(int $id): JSONResponse {
+		return new JSONResponse($this->accountService->find($this->currentUserId, $id));
 	}
 
 	/**
@@ -198,7 +222,7 @@ class AccountsController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
+	 * @param int $id
 	 * @param string|null $editorMode
 	 * @param int|null $order
 	 * @param bool|null $showSubscribedOnly
@@ -207,11 +231,11 @@ class AccountsController extends Controller {
 	 *
 	 * @throws ClientException
 	 */
-	public function patchAccount(int $accountId,
+	public function patchAccount(int $id,
 								 string $editorMode = null,
 								 int $order = null,
 								 bool $showSubscribedOnly = null): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+		$account = $this->accountService->find($this->currentUserId, $id);
 
 		if ($account === null) {
 			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
@@ -236,7 +260,7 @@ class AccountsController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
+	 * @param int $id
 	 * @param string|null $signature
 	 *
 	 * @return JSONResponse
@@ -244,8 +268,8 @@ class AccountsController extends Controller {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function updateSignature(int $accountId, string $signature = null): JSONResponse {
-		$this->accountService->updateSignature($accountId, $this->currentUserId, $signature);
+	public function updateSignature(int $id, string $signature = null): JSONResponse {
+		$this->accountService->updateSignature($id, $this->currentUserId, $signature);
 		return new JSONResponse();
 	}
 
@@ -259,7 +283,7 @@ class AccountsController extends Controller {
 	 *
 	 * @throws ClientException
 	 */
-	public function destroy($id): JSONResponse {
+	public function destroy(int $id): JSONResponse {
 		$this->accountService->delete($this->currentUserId, $id);
 		return new JSONResponse();
 	}
@@ -315,13 +339,13 @@ class AccountsController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
+	 * @param int $id
 	 * @param string $subject
 	 * @param string $body
 	 * @param string $to
 	 * @param string $cc
 	 * @param string $bcc
-	 * @param int|null $draftUID
+	 * @param int|null $draftId
 	 * @param string|null $folderId
 	 * @param int|null $messageId
 	 * @param mixed $attachments
@@ -332,19 +356,19 @@ class AccountsController extends Controller {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function send(int $accountId,
+	public function send(int $id,
 						 string $subject,
 						 string $body,
 						 string $to,
 						 string $cc,
 						 string $bcc,
 						 bool $isHtml = true,
-						 int $draftUID = null,
+						 int $draftId = null,
 						 string $folderId = null,
 						 int $messageId = null,
 						 array $attachments = [],
 						 int $aliasId = null): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+		$account = $this->accountService->find($this->currentUserId, $id);
 		$alias = $aliasId ? $this->aliasesService->find($aliasId, $this->currentUserId) : null;
 
 		$expandedTo = $this->groupsIntegration->expand($to);
@@ -357,8 +381,16 @@ class AccountsController extends Controller {
 			$repliedMessageData = new RepliedMessageData($account, base64_decode($folderId), $messageId);
 		}
 
+		$draft = null;
+		if ($draftId !== null) {
+			try {
+				$draft = $this->mailManager->getMessage($this->currentUserId, $draftId);
+			} catch (ClientException $e) {
+				$this->logger->info("Draft " . $draftId . " could not be loaded: " . $e->getMessage());
+			}
+		}
 		try {
-			$this->mailTransmission->sendMessage($messageData, $repliedMessageData, $alias, $draftUID);
+			$this->mailTransmission->sendMessage($messageData, $repliedMessageData, $alias, $draft);
 			return new JSONResponse();
 		} catch (ServiceException $ex) {
 			$this->logger->error('Sending mail failed: ' . $ex->getMessage());
@@ -370,7 +402,7 @@ class AccountsController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
+	 * @param int $id
 	 * @param string $subject
 	 * @param string $body
 	 * @param string $to
@@ -382,27 +414,43 @@ class AccountsController extends Controller {
 	 *
 	 * @throws ClientException
 	 */
-	public function draft(int $accountId,
-						  string $subject = null,
+	public function draft(int $id,
+						  string $subject,
 						  string $body,
 						  string $to,
 						  string $cc,
 						  string $bcc,
 						  bool $isHtml = true,
-						  int $draftUID = null): JSONResponse {
-		if ($draftUID === null) {
-			$this->logger->info("Saving a new draft in account <$accountId>");
+						  int $draftId = null): JSONResponse {
+		if ($draftId === null) {
+			$this->logger->info("Saving a new draft in account <$id>");
 		} else {
-			$this->logger->info("Updating draft <$draftUID> in account <$accountId>");
+			$this->logger->info("Updating draft <$draftId> in account <$id>");
 		}
 
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+		$account = $this->accountService->find($this->currentUserId, $id);
+		$previousDraft = null;
+		if ($draftId !== null) {
+			try {
+				$previousDraft = $this->mailManager->getMessage($this->currentUserId, $draftId);
+			} catch (ClientException $e) {
+				$this->logger->info("Draft " . $draftId . " could not be loaded: " . $e->getMessage());
+			}
+		}
 		$messageData = NewMessageData::fromRequest($account, $to, $cc, $bcc, $subject, $body, [], $isHtml);
 
 		try {
-			$newUID = $this->mailTransmission->saveDraft($messageData, $draftUID);
+			/** @var Mailbox $draftsMailbox */
+			[, $draftsMailbox, $newUID] = $this->mailTransmission->saveDraft($messageData, $previousDraft);
+			$this->syncService->syncMailbox(
+				$account,
+				$draftsMailbox,
+				Horde_Imap_Client::SYNC_NEWMSGS,
+				[],
+				false
+			);
 			return new JSONResponse([
-				'uid' => $newUID,
+				'id' => $this->mailManager->getMessageIdForUid($draftsMailbox, $newUID)
 			]);
 		} catch (ServiceException $ex) {
 			$this->logger->error('Saving draft failed: ' . $ex->getMessage());
@@ -413,13 +461,13 @@ class AccountsController extends Controller {
 	/**
 	 * @NoAdminRequired
 	 *
-	 * @param int $accountId
+	 * @param int $id
 	 *
 	 * @return JSONResponse
 	 * @throws ClientException
 	 */
-	public function getQuota(int $accountId): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+	public function getQuota(int $id): JSONResponse {
+		$account = $this->accountService->find($this->currentUserId, $id);
 
 		$quota = $this->mailManager->getQuota($account);
 		if ($quota === null) {
diff --git a/lib/Controller/AliasesController.php b/lib/Controller/AliasesController.php
index cda86bd65..ca9d61589 100644
--- a/lib/Controller/AliasesController.php
+++ b/lib/Controller/AliasesController.php
@@ -54,9 +54,10 @@ class AliasesController extends Controller {
 	 * @TrapError
 	 *
 	 * @param int $accountId
+	 *
 	 * @return JSONResponse
 	 */
-	public function index($accountId): JSONResponse {
+	public function index(int $accountId): JSONResponse {
 		return new JSONResponse($this->aliasService->findAll($accountId, $this->currentUser->getUID()));
 	}
 
@@ -83,7 +84,7 @@ class AliasesController extends Controller {
 	 * @param int $id
 	 * @return JSONResponse
 	 */
-	public function destroy($id): JSONResponse {
+	public function destroy(int $id): JSONResponse {
 		return new JSONResponse($this->aliasService->delete($id, $this->currentUser->getUID()));
 	}
 
@@ -94,9 +95,10 @@ class AliasesController extends Controller {
 	 * @param int $accountId
 	 * @param string $alias
 	 * @param string $aliasName
+	 *
 	 * @return JSONResponse
 	 */
-	public function create($accountId, $alias, $aliasName): JSONResponse {
+	public function create(int $accountId, string $alias, string $aliasName): JSONResponse {
 		return new JSONResponse($this->aliasService->create($accountId, $alias, $aliasName), Http::STATUS_CREATED);
 	}
 }
diff --git a/lib/Controller/FoldersController.php b/lib/Controller/MailboxesController.php
index 2527658e5..c7ad55007 100644
--- a/lib/Controller/FoldersController.php
+++ b/lib/Controller/MailboxesController.php
@@ -31,8 +31,6 @@ use OCA\Mail\Exception\IncompleteSyncException;
 use OCA\Mail\Exception\MailboxNotCachedException;
 use OCA\Mail\Exception\ServiceException;
 use OCA\Mail\Service\Sync\SyncService;
-use function base64_decode;
-use function is_array;
 use OCA\Mail\Contracts\IMailManager;
 use OCA\Mail\Exception\NotImplemented;
 use OCA\Mail\Service\AccountService;
@@ -41,7 +39,7 @@ use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
 use OCP\IRequest;
 
-class FoldersController extends Controller {
+class MailboxesController extends Controller {
 
 	/** @var AccountService */
 	private $accountService;
@@ -66,7 +64,7 @@ class FoldersController extends Controller {
 	public function __construct(string $appName,
 								IRequest $request,
 								AccountService $accountService,
-								$UserId,
+								?string $UserId,
 								IMailManager $mailManager,
 								SyncService $syncService) {
 		parent::__construct($appName, $request);
@@ -94,7 +92,7 @@ class FoldersController extends Controller {
 		return new JSONResponse([
 			'id' => $accountId,
 			'email' => $account->getEmail(),
-			'folders' => $mailboxes,
+			'mailboxes' => $mailboxes,
 			'delimiter' => reset($mailboxes)->getDelimiter(),
 		]);
 	}
@@ -103,30 +101,28 @@ class FoldersController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
-	 * @param string $syncToken
-	 * @param int[] $uids
+	 * @param int $id
+	 * @param int[] $ids
+	 *
+	 * @param bool $init
+	 * @param string|null $query
 	 *
 	 * @return JSONResponse
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function sync(int $accountId, string $folderId, array $uids = [], bool $init = false, string $query = null): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
-
-		if (empty($accountId) || empty($folderId) || !is_array($uids)) {
-			return new JSONResponse(null, Http::STATUS_BAD_REQUEST);
-		}
+	public function sync(int $id, array $ids = [], bool $init = false, string $query = null): JSONResponse {
+		$mailbox = $this->mailManager->getMailbox($this->currentUserId, $id);
+		$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 
 		try {
 			$syncResponse = $this->syncService->syncMailbox(
 				$account,
-				base64_decode($folderId),
+				$mailbox,
 				Horde_Imap_Client::SYNC_NEWMSGSUIDS | Horde_Imap_Client::SYNC_FLAGSUIDS | Horde_Imap_Client::SYNC_VANISHEDUIDS,
-				array_map(function ($uid) {
-					return (int) $uid;
-				}, $uids),
+				array_map(function ($id) {
+					return (int) $id;
+				}, $ids),
 				!$init,
 				$query
 			);
@@ -143,21 +139,17 @@ class FoldersController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
+	 * @param string $id
 	 *
 	 * @return JSONResponse
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function clearCache(int $accountId, string $folderId): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+	public function clearCache(int $id): JSONResponse {
+		$mailbox = $this->mailManager->getMailbox($this->currentUserId, $id);
+		$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 
-		if (empty($accountId) || empty($folderId)) {
-			return new JSONResponse(null, Http::STATUS_BAD_REQUEST);
-		}
-
-		$this->syncService->clearCache($account, base64_decode($folderId));
+		$this->syncService->clearCache($account, $mailbox);
 		return new JSONResponse(null);
 	}
 
@@ -165,43 +157,37 @@ class FoldersController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
+	 * @param int $id
+	 *
 	 * @return JSONResponse
 	 *
 	 * @throws ClientException
 	 */
-	public function markAllAsRead(int $accountId, string $folderId): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
-
-		if (empty($accountId) || empty($folderId)) {
-			return new JSONResponse(null, Http::STATUS_BAD_REQUEST);
-		}
+	public function markAllAsRead(int $id): JSONResponse {
+		$mailbox = $this->mailManager->getMailbox($this->currentUserId, $id);
+		$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 
-		$syncResponse = $this->mailManager->markFolderAsRead($account, base64_decode($folderId));
+		$this->mailManager->markFolderAsRead($account, $mailbox);
 
-		return new JSONResponse($syncResponse);
+		return new JSONResponse(null);
 	}
 
 	/**
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
+	 * @param int $id
 	 *
 	 * @return JSONResponse
 	 *
 	 * @throws ClientException
+	 * @throws ServiceException
 	 */
-	public function stats(int $accountId, string $folderId): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
-
-		if (empty($accountId) || empty($folderId)) {
-			return new JSONResponse(null, Http::STATUS_BAD_REQUEST);
-		}
+	public function stats(int $id): JSONResponse {
+		$mailbox = $this->mailManager->getMailbox($this->currentUserId, $id);
+		$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 
-		$stats = $this->mailManager->getFolderStats($account, base64_decode($folderId));
+		$stats = $this->mailManager->getMailboxStats($account, $mailbox);
 
 		return new JSONResponse($stats);
 	}
@@ -232,19 +218,24 @@ class FoldersController extends Controller {
 	public function create(int $accountId, string $name) {
 		$account = $this->accountService->find($this->currentUserId, $accountId);
 
-		return new JSONResponse($this->mailManager->createFolder($account, $name));
+		return new JSONResponse($this->mailManager->createMailbox($account, $name));
 	}
 
 	/**
 	 * @NoAdminRequired
 	 * @TrapError
-	 * @param int $accountId
-	 * @param string $folderId
+	 *
+	 * @param int $id
+	 *
+	 * @return JSONResponse
+	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function delete(int $accountId, string $folderId): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
-		$this->mailManager->deleteMailbox($account,  base64_decode($folderId));
+	public function destroy(int $id): JSONResponse {
+		$mailbox = $this->mailManager->getMailbox($this->currentUserId, $id);
+		$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
+
+		$this->mailManager->deleteMailbox($account,  $mailbox);
 		return new JSONResponse();
 	}
 }
diff --git a/lib/Controller/MessagesController.php b/lib/Controller/MessagesController.php
index ef6357835..df602bf94 100755
--- a/lib/Controller/MessagesController.php
+++ b/lib/Controller/MessagesController.php
@@ -39,7 +39,6 @@ use OCA\Mail\Http\AttachmentDownloadResponse;
 use OCA\Mail\Http\HtmlResponse;
 use OCA\Mail\Model\IMAPMessage;
 use OCA\Mail\Service\AccountService;
-use OCA\Mail\Service\IMailBox;
 use OCA\Mail\Service\ItineraryService;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Db\DoesNotExistException;
@@ -55,7 +54,6 @@ use OCP\ILogger;
 use OCP\IRequest;
 use OCP\IURLGenerator;
 use function array_map;
-use function base64_decode;
 
 class MessagesController extends Controller {
 
@@ -131,29 +129,33 @@ class MessagesController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
+	 * @param int $mailboxId
 	 * @param int $cursor
 	 * @param string $filter
+	 * @param int|null $limit
 	 *
 	 * @return JSONResponse
 	 *
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function index(int $accountId, string $folderId, int $cursor = null, string $filter = null, int $limit = null): JSONResponse {
+	public function index(int $mailboxId,
+						  int $cursor = null,
+						  string $filter = null,
+						  int $limit = null): JSONResponse {
 		try {
-			$account = $this->accountService->find($this->currentUserId, $accountId);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $mailboxId);
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 		} catch (DoesNotExistException $e) {
 			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
 		}
 
-		$this->logger->debug("loading messages of folder <$folderId>");
+		$this->logger->debug("loading messages of folder <$mailboxId>");
 
 		return new JSONResponse(
 			$this->mailSearch->findMessages(
 				$account,
-				base64_decode($folderId),
+				$mailbox,
 				$filter === '' ? null : $filter,
 				$cursor,
 				$limit
@@ -174,20 +176,22 @@ class MessagesController extends Controller {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function show(int $accountId, string $folderId, int $id): JSONResponse {
+	public function show(int $id): JSONResponse {
 		try {
-			$account = $this->accountService->find($this->currentUserId, $accountId);
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 		} catch (DoesNotExistException $e) {
 			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
 		}
 
-		$this->logger->debug("loading message of folder <$folderId>");
+		$this->logger->debug("loading message <$id>");
 
 		return new JSONResponse(
 			$this->mailSearch->findMessage(
 				$account,
-				base64_decode($folderId),
-				$id
+				$mailbox,
+				$message
 			)
 		);
 	}
@@ -196,40 +200,40 @@ class MessagesController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
-	 * @param int $messageId
+	 * @param int $id
 	 *
 	 * @return JSONResponse
 	 *
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function getBody(int $accountId, string $folderId, int $messageId): JSONResponse {
+	public function getBody(int $id): JSONResponse {
 		try {
-			$account = $this->accountService->find($this->currentUserId, $accountId);
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 		} catch (DoesNotExistException $e) {
 			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
 		}
 
-		$json = $this->mailManager->getMessage(
+		$json = $this->mailManager->getImapMessage(
 			$account,
-			base64_decode($folderId),
-			$messageId,
+			$mailbox,
+			$message->getUid(),
 			true
-		)->getFullMessage(
-			$accountId,
-			base64_decode($folderId),
-			$messageId
-		);
+		)->getFullMessage($id);
 		$json['itineraries'] = $this->itineraryService->extract(
 			$account,
-			base64_decode($folderId),
-			$messageId
+			$mailbox->getName(),
+			$message->getUid()
 		);
-		$json['attachments'] = array_map(function ($a) use ($accountId, $folderId, $messageId) {
-			return $this->enrichDownloadUrl($accountId, $folderId, $messageId, $a);
+		$json['attachments'] = array_map(function ($a) use ($id) {
+			return $this->enrichDownloadUrl(
+				$id,
+				$a
+			);
 		}, $json['attachments']);
+		$json['databaseId'] = $message->getId();
 
 		return new JSONResponse($json);
 	}
@@ -239,14 +243,19 @@ class MessagesController extends Controller {
 	 * @NoCSRFRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
+	 * @param int $id
 	 *
 	 * @return JSONResponse
 	 * @throws ClientException
 	 */
-	public function getThread(int $accountId, int $id): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+	public function getThread(int $id): JSONResponse {
+		try {
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
+		} catch (DoesNotExistException $e) {
+			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
+		}
 
 		return new JSONResponse($this->mailManager->getThread($account, $id));
 	}
@@ -255,10 +264,7 @@ class MessagesController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
 	 * @param int $id
-	 * @param int $destAccountId
 	 * @param string $destFolderId
 	 *
 	 * @return JSONResponse
@@ -266,12 +272,24 @@ class MessagesController extends Controller {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function move($accountId, $folderId, $id, $destAccountId, $destFolderId): JSONResponse {
-		$srcAccount = $this->accountService->find($this->currentUserId, $accountId);
-		$dstAccount = $this->accountService->find($this->currentUserId,
-			$destAccountId);
-		$this->mailManager->moveMessage($srcAccount, base64_decode($folderId), $id,
-			$dstAccount, base64_decode($destFolderId));
+	public function move(int $id, int $destFolderId): JSONResponse {
+		try {
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$srcMailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$dstMailbox = $this->mailManager->getMailbox($this->currentUserId, $destFolderId);
+			$srcAccount = $this->accountService->find($this->currentUserId, $srcMailbox->getAccountId());
+			$dstAccount = $this->accountService->find($this->currentUserId, $dstMailbox->getAccountId());
+		} catch (DoesNotExistException $e) {
+			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
+		}
+
+		$this->mailManager->moveMessage(
+			$srcAccount,
+			$srcMailbox->getName(),
+			$message->getUid(),
+			$dstAccount,
+			$dstMailbox->getName()
+		);
 		return new JSONResponse();
 	}
 
@@ -284,17 +302,23 @@ class MessagesController extends Controller {
 	 * @param string $folderId
 	 * @param int $messageId
 	 *
-	 * @return HtmlResponse|TemplateResponse
+	 * @return JSONResponse
 	 * @throws ServiceException
 	 */
-	public function getSource(int $accountId, string $folderId, int $messageId): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+	public function getSource(int $id): JSONResponse {
+		try {
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
+		} catch (DoesNotExistException $e) {
+			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
+		}
 
 		$response = new JSONResponse([
 			'source' => $this->mailManager->getSource(
 				$account,
-				base64_decode($folderId),
-				$messageId
+				$mailbox->getName(),
+				$message->getUid()
 			)
 		]);
 
@@ -309,18 +333,18 @@ class MessagesController extends Controller {
 	 * @NoCSRFRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
-	 * @param int $messageId
+	 * @param int $id
 	 *
 	 * @return HtmlResponse|TemplateResponse
 	 *
 	 * @throws ClientException
 	 */
-	public function getHtmlBody(int $accountId, string $folderId, int $messageId): Response {
+	public function getHtmlBody(int $id): Response {
 		try {
 			try {
-				$account = $this->accountService->find($this->currentUserId, $accountId);
+				$message = $this->mailManager->getMessage($this->currentUserId, $id);
+				$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+				$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 			} catch (DoesNotExistException $e) {
 				return new TemplateResponse(
 					$this->appName,
@@ -331,12 +355,14 @@ class MessagesController extends Controller {
 			}
 
 			$htmlResponse = new HtmlResponse(
-				$this->mailManager->getMessage(
+				$this->mailManager->getImapMessage(
 					$account,
-					base64_decode($folderId),
-					$messageId,
+					$mailbox,
+					$message->getUid(),
 					true
-				)->getHtmlBody($accountId, base64_decode($folderId), $messageId)
+				)->getHtmlBody(
+					$id
+				)
 			);
 
 			// Harden the default security policy
@@ -369,19 +395,25 @@ class MessagesController extends Controller {
 	 *
 	 * @param int $accountId
 	 * @param string $folderId
-	 * @param int $messageId
+	 * @param int $id
 	 * @param int $attachmentId
 	 *
-	 * @return AttachmentDownloadResponse
+	 * @return Response
 	 *
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function downloadAttachment(int $accountId, string $folderId, int $messageId,
-									   string $attachmentId) {
-		$mailBox = $this->getFolder($accountId, $folderId);
-
-		$attachment = $mailBox->getAttachment($messageId, $attachmentId);
+	public function downloadAttachment(int $id,
+									   string $attachmentId): Response {
+		try {
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
+		} catch (DoesNotExistException $e) {
+			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
+		}
+		$folder = $account->getMailbox($mailbox->getName());
+		$attachment = $folder->getAttachment($message->getUid(), $attachmentId);
 
 		// Body party and embedded messages do not have a name
 		if ($attachment->getName() === null) {
@@ -404,9 +436,7 @@ class MessagesController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
-	 * @param int $messageId
+	 * @param int $id
 	 * @param int $attachmentId
 	 * @param string $targetPath
 	 *
@@ -415,14 +445,22 @@ class MessagesController extends Controller {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function saveAttachment(int $accountId, string $folderId, int $messageId,
-								   string $attachmentId, string $targetPath) {
-		$mailBox = $this->getFolder($accountId, $folderId);
+	public function saveAttachment(int $id,
+								   string $attachmentId,
+								   string $targetPath) {
+		try {
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
+		} catch (DoesNotExistException $e) {
+			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
+		}
+		$folder = $account->getMailbox($mailbox->getName());
 
 		if ($attachmentId === '0') {
 			// Save all attachments
 			/* @var $m IMAPMessage */
-			$m = $mailBox->getMessage($messageId);
+			$m = $folder->getMessage($id);
 			$attachmentIds = array_map(function ($a) {
 				return $a['id'];
 			}, $m->attachments);
@@ -430,11 +468,11 @@ class MessagesController extends Controller {
 			$attachmentIds = [$attachmentId];
 		}
 
-		foreach ($attachmentIds as $attachmentId) {
-			$attachment = $mailBox->getAttachment($messageId, $attachmentId);
+		foreach ($attachmentIds as $aid) {
+			$attachment = $folder->getAttachment($message->getUid(), $attachmentId);
 
 			$fileName = $attachment->getName() ?? $this->l10n->t('Embedded message %s', [
-				$attachmentId,
+				$aid,
 			]) . '.eml';
 			$fileParts = pathinfo($fileName);
 			$fileName = $fileParts['filename'];
@@ -456,9 +494,7 @@ class MessagesController extends Controller {
 	 * @NoAdminRequired
 	 * @TrapError
 	 *
-	 * @param int $accountId
-	 * @param string $folderId
-	 * @param string $messageId
+	 * @param string $id
 	 * @param array $flags
 	 *
 	 * @return JSONResponse
@@ -466,12 +502,18 @@ class MessagesController extends Controller {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function setFlags(int $accountId, string $folderId, int $messageId, array $flags): JSONResponse {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
+	public function setFlags(int $id, array $flags): JSONResponse {
+		try {
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
+		} catch (DoesNotExistException $e) {
+			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
+		}
 
 		foreach ($flags as $flag => $value) {
 			$value = filter_var($value, FILTER_VALIDATE_BOOLEAN);
-			$this->mailManager->flagMessage($account, base64_decode($folderId), $messageId, $flag, $value);
+			$this->mailManager->flagMessage($account, $mailbox->getName(), $message->getUid(), $flag, $value);
 		}
 		return new JSONResponse();
 	}
@@ -489,49 +531,36 @@ class MessagesController extends Controller {
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function destroy(int $accountId, string $folderId, int $id): JSONResponse {
-		$this->logger->debug("deleting message <$id> of folder <$folderId>, account <$accountId>");
-
+	public function destroy(int $id): JSONResponse {
 		try {
-			$account = $this->accountService->find($this->currentUserId, $accountId);
+			$message = $this->mailManager->getMessage($this->currentUserId, $id);
+			$mailbox = $this->mailManager->getMailbox($this->currentUserId, $message->getMailboxId());
+			$account = $this->accountService->find($this->currentUserId, $mailbox->getAccountId());
 		} catch (DoesNotExistException $e) {
 			return new JSONResponse(null, Http::STATUS_FORBIDDEN);
 		}
 
-		$this->mailManager->deleteMessage($account, base64_decode($folderId), $id);
-		return new JSONResponse();
-	}
+		$this->logger->debug("deleting message <$id>");
 
-	/**
-	 * @param int $accountId
-	 * @param string $folderId
-	 *
-	 * @return IMailBox
-	 * @deprecated
-	 *
-	 * @throws ClientException
-	 * @throws ServiceException
-	 */
-	private function getFolder(int $accountId, string $folderId): IMailBox {
-		$account = $this->accountService->find($this->currentUserId, $accountId);
-		return $account->getMailbox(base64_decode($folderId));
+		$this->mailManager->deleteMessage(
+			$account,
+			$mailbox->getName(),
+			$message->getUid()
+		);
+		return new JSONResponse();
 	}
 
 	/**
-	 * @param int $accountId
-	 * @param string $folderId
-	 * @param int $messageId
+	 * @param int $id
 	 * @param array $attachment
 	 *
 	 * @return array
 	 */
-	private function enrichDownloadUrl(int $accountId, string $folderId, int $messageId,
+	private function enrichDownloadUrl(int $id,
 									   array $attachment) {
 		$downloadUrl = $this->urlGenerator->linkToRoute('mail.messages.downloadAttachment',
 			[
-				'accountId' => $accountId,
-				'folderId' => $folderId,
-				'messageId' => $messageId,
+				'id' => $id,
 				'attachmentId' => $attachment['id'],
 			]);
 		$downloadUrl = $this->urlGenerator->getAbsoluteURL($downloadUrl);
diff --git a/lib/Controller/PageController.php b/lib/Controller/PageController.php
index 219bb16ff..fe9181760 100644
--- a/lib/Controller/PageController.php
+++ b/lib/Controller/PageController.php
@@ -117,13 +117,13 @@ class PageController extends Controller {
 				$this->currentUserId);
 			try {
 				$mailboxes = $this->mailManager->getMailboxes($mailAccount);
-				$json['folders'] = $mailboxes;
+				$json['mailboxes'] = $mailboxes;
 			} catch (Exception $ex) {
 				$this->logger->logException($ex, [
-					'message' => 'Could not load account folders: ' . $ex->getMessage(),
+					'message' => 'Could not load account mailboxes: ' . $ex->getMessage(),
 					'level' => ILogger::FATAL,
 				]);
-				$json['folders'] = [];
+				$json['mailboxes'] = [];
 				$json['error'] = true;
 			}
 			$accountsJson[] = $json;
@@ -160,6 +160,56 @@ class PageController extends Controller {
 	 * @NoAdminRequired
 	 * @NoCSRFRequired
 	 *
+	 * @return TemplateResponse
+	 */
+	public function setup(): TemplateResponse {
+		return $this->index();
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @NoCSRFRequired
+	 *
+	 * @return TemplateResponse
+	 */
+	public function keyboardShortcuts(): TemplateResponse {
+		return $this->index();
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @NoCSRFRequired
+	 *
+	 * @return TemplateResponse
+	 */
+	public function accountSettings(int $id): TemplateResponse {
+		return $this->index();
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @NoCSRFRequired
+	 *
+	 * @return TemplateResponse
+	 */
+	public function mailbox(int $id): TemplateResponse {
+		return $this->index();
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @NoCSRFRequired
+	 *
+	 * @return TemplateResponse
+	 */
+	public function thread(int $mailboxId, int $id): TemplateResponse {
+		return $this->index();
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @NoCSRFRequired
+	 *
 	 * @param string $uri
 	 *
 	 * @return RedirectResponse
diff --git a/lib/Db/MailAccount.php b/lib/Db/MailAccount.php
index 36fb54cdf..c63abe27c 100644
--- a/lib/Db/MailAccount.php
+++ b/lib/Db/MailAccount.php
@@ -153,6 +153,7 @@ class MailAccount extends Entity {
 	 */
 	public function toJson() {
 		$result = [
+			'id' => $this->getId(),
 			'accountId' => $this->getId(),
 			'name' => $this->getName(),
 			'order' => $this->getOrder(),
diff --git a/lib/Db/Mailbox.php b/lib/Db/Mailbox.php
index 2a877ee64..0da25c85f 100644
--- a/lib/Db/Mailbox.php
+++ b/lib/Db/Mailbox.php
@@ -121,12 +121,14 @@ class Mailbox extends Entity implements JsonSerializable {
 		return [
 			'databaseId' => $this->getId(),
 			'id' => base64_encode($this->getName()),
+			'name' => $this->getName(),
 			'accountId' => $this->accountId,
 			'displayName' => $this->getName(),
 			'attributes' => json_decode($this->attributes ?? '[]', true) ?? [],
 			'delimiter' => $this->delimiter,
 			'specialUse' => $specialUse,
 			'specialRole' => $specialUse[0] ?? 0,
+			'mailboxes' => [],
 		];
 	}
 }
diff --git a/lib/Db/MailboxMapper.php b/lib/Db/MailboxMapper.php
index d2361b927..0b2ae36ce 100644
--- a/lib/Db/MailboxMapper.php
+++ b/lib/Db/MailboxMapper.php
@@ -85,6 +85,34 @@ class MailboxMapper extends QBMapper {
 	}
 
 	/**
+	 * @param int $id
+	 * @param string $uid
+	 *
+	 * @return Mailbox
+	 *
+	 * @throws DoesNotExistException
+	 * @throws ServiceException
+	 */
+	public function findByUid(int $id, string $uid): Mailbox {
+		$qb = $this->db->getQueryBuilder();
+
+		$select = $qb->select('mb.*')
+			->from($this->getTableName(), 'mb')
+			->join('mb', 'mail_accounts', 'a', $qb->expr()->eq('mb.account_id', 'a.id', IQueryBuilder::PARAM_INT))
+			->where(
+				$qb->expr()->eq('a.user_id', $qb->createNamedParameter($uid)),
+				$qb->expr()->eq('mb.id', $qb->createNamedParameter($id, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT)
+			);
+
+		try {
+			return $this->findEntity($select);
+		} catch (MultipleObjectsReturnedException $e) {
+			// Not possible due to DB constraints
+			throw new ServiceException("The impossible has happened", 42, $e);
+		}
+	}
+
+	/**
 	 * @throws DoesNotExistException
 	 */
 	public function findSpecial(Account $account, string $specialUse): Mailbox {
diff --git a/lib/Db/Message.php b/lib/Db/Message.php
index 8f028a284..95248b132 100644
--- a/lib/Db/Message.php
+++ b/lib/Db/Message.php
@@ -126,6 +126,7 @@ class Message extends Entity implements JsonSerializable {
 		$this->bcc = new AddressList([]);
 
 		$this->addType('uid', 'integer');
+		$this->addType('mailboxId', 'integer');
 		$this->addType('sentAt', 'integer');
 		$this->addType('flagAnswered', 'bool');
 		$this->addType('flagDeleted', 'bool');
@@ -252,6 +253,7 @@ class Message extends Entity implements JsonSerializable {
 			'to' => $this->getTo()->jsonSerialize(),
 			'cc' => $this->getCc()->jsonSerialize(),
 			'bcc' => $this->getBcc()->jsonSerialize(),
+			'mailboxId' => $this->getMailboxId(),
 		];
 	}
 }
diff --git a/lib/Db/MessageMapper.php b/lib/Db/MessageMapper.php
index e6593bb8c..77d0564ed 100644
--- a/lib/Db/MessageMapper.php
+++ b/lib/Db/MessageMapper.php
@@ -31,6 +31,7 @@ use OCA\Mail\Address;
 use OCA\Mail\AddressList;
 use OCA\Mail\IMAP\Threading\DatabaseMessage;
 use OCA\Mail\Service\Search\SearchQuery;
+use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\AppFramework\Db\QBMapper;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\DB\QueryBuilder\IQueryBuilder;
@@ -51,6 +52,11 @@ class MessageMapper extends QBMapper {
 		$this->timeFactory = $timeFactory;
 	}
 
+	/**
+	 * @param IQueryBuilder $query
+	 *
+	 * @return int[]
+	 */
 	private function findUids(IQueryBuilder $query): array {
 		$result = $query->execute();
 		$uids = array_map(function (array $row) {
@@ -61,6 +67,21 @@ class MessageMapper extends QBMapper {
 		return $uids;
 	}
 
+	/**
+	 * @param IQueryBuilder $query
+	 *
+	 * @return int[]
+	 */
+	private function findIds(IQueryBuilder $query): array {
+		$result = $query->execute();
+		$uids = array_map(function (array $row) {
+			return (int)$row['id'];
+		}, $result->fetchAll());
+		$result->closeCursor();
+
+		return $uids;
+	}
+
 	public function findHighestUid(Mailbox $mailbox): ?int {
 		$query = $this->db->getQueryBuilder();
 
@@ -78,12 +99,64 @@ class MessageMapper extends QBMapper {
 		return $max;
 	}
 
+	public function findByUserId(string $uid, int $id): Message {
+		$query = $this->db->getQueryBuilder();
+
+		$query->select('m.*')
+			->from($this->getTableName(), 'm')
+			->join('m', 'mail_mailboxes', 'mb', $query->expr()->eq('m.mailbox_id', 'mb.id', IQueryBuilder::PARAM_INT))
+			->join('m', 'mail_accounts', 'a', $query->expr()->eq('mb.account_id', 'a.id', IQueryBuilder::PARAM_INT))
+			->where(
+				$query->expr()->eq('a.user_id', $query->createNamedParameter($uid)),
+				$query->expr()->eq('m.id', $query->createNamedParameter($id, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT)
+			);
+
+		$results = $this->findRecipients($this->findEntities($query));
+		if (empty($results)) {
+			throw new DoesNotExistException("Message $id does not exist");
+		}
+		return $results[0];
+	}
+
 	public function findAllUids(Mailbox $mailbox): array {
 		$query = $this->db->getQueryBuilder();
 
 		$query->select('uid')
 			->from($this->getTableName())
-			->where($query->expr()->eq('mailbox_id', $query->createNamedParameter($mailbox->getId())));
+			->where($query->expr()->eq('mailbox_id', $query->createNamedParameter($mailbox->getId(), IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT));
+
+		return $this->findUids($query);
+	}
+
+	public function findAllIds(Mailbox $mailbox): array {
+		$query = $this->db->getQueryBuilder();
+
+		$query->select('id')
+			->from($this->getTableName())
+			->where($query->expr()->eq('mailbox_id', $query->createNamedParameter($mailbox->getId(), IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT));
+
+		return $this->findIds($query);
+	}
+
+	/**
+	 * @param Mailbox $mailbox
+	 * @param int[] $ids
+	 *
+	 * @return int[]
+	 */
+	public function findUidsForIds(Mailbox $mailbox, array $ids) {
+		if (empty($ids)) {
+			// Shortcut for empty sets
+			return [];
+		}
+
+		$query = $this->db->getQueryBuilder();
+		$query->select('uid')
+			->from($this->getTableName())
+			->where(
+				$query->expr()->eq('mailbox_id', $query->createNamedParameter($mailbox->getId(), IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT),
+				$query->expr()->in('id', $query->createNamedParameter($ids, IQueryBuilder::PARAM_INT_ARRAY), IQueryBuilder::PARAM_INT_ARRAY)
+			);
 
 		return $this->findUids($query);
 	}
@@ -382,11 +455,11 @@ class MessageMapper extends QBMapper {
 	 *
 	 * @return int[]
 	 */
-	public function findUidsByQuery(Mailbox $mailbox, SearchQuery $query, ?int $limit, array $uids = null): array {
+	public function findIdsByQuery(Mailbox $mailbox, SearchQuery $query, ?int $limit, array $uids = null): array {
 		$qb = $this->db->getQueryBuilder();
 
 		$select = $qb
-			->selectDistinct('m.uid')
+			->selectDistinct('m.id')
 			->addSelect('m.sent_at')
 			->from($this->getTableName(), 'm');
 
@@ -477,7 +550,7 @@ class MessageMapper extends QBMapper {
 		}
 
 		return array_map(function (Message $message) {
-			return $message->getUid();
+			return $message->getId();
 		}, $this->findEntities($select));
 	}
 
@@ -503,6 +576,28 @@ class MessageMapper extends QBMapper {
 	}
 
 	/**
+	 * @param int[] $ids
+	 *
+	 * @return Message[]
+	 */
+	public function findByIds(array $ids): array {
+		if (empty($ids)) {
+			return [];
+		}
+		$qb = $this->db->getQueryBuilder();
+
+		$select = $qb
+			->select('*')
+			->from($this->getTableName())
+			->where(
+				$qb->expr()->in('id', $qb->createNamedParameter($ids, IQueryBuilder::PARAM_INT_ARRAY), IQueryBuilder::PARAM_INT_ARRAY)
+			)
+			->orderBy('sent_at', 'desc');
+
+		return $this->findRecipients($this->findEntities($select));
+	}
+
+	/**
 	 * @param Message[] $messages
 	 *
 	 * @return Message[]
@@ -558,18 +653,26 @@ class MessageMapper extends QBMapper {
 	 *
 	 * @return Message[]
 	 */
-	public function findNewUids(Mailbox $mailbox, int $highest): array {
+	public function findNewIds(Mailbox $mailbox, array $ids): array {
 		$qb = $this->db->getQueryBuilder();
+		$sub = $this->db->getQueryBuilder();
 
+		$subSelect = $sub
+			->select($sub->func()->max('uid'))
+			->from($this->getTableName())
+			->where(
+				$sub->expr()->eq('mailbox_id', $qb->createNamedParameter($mailbox->getId(), IQueryBuilder::PARAM_INT)),
+				$sub->expr()->in('id', $qb->createNamedParameter($ids, IQueryBuilder::PARAM_INT_ARRAY), IQueryBuilder::PARAM_INT_ARRAY)
+			);
 		$select = $qb
-			->select('uid')
+			->select('id')
 			->from($this->getTableName())
 			->where(
 				$qb->expr()->eq('mailbox_id', $qb->createNamedParameter($mailbox->getId(), IQueryBuilder::PARAM_INT)),
-				$qb->expr()->gt('uid', $qb->createNamedParameter($highest, IQueryBuilder::PARAM_INT))
+				$qb->expr()->gt('uid', $qb->createFunction('(' . $subSelect->getSQL() . ')'), IQueryBuilder::PARAM_INT)
 			);
 
-		return $this->findUids($select);
+		return $this->findIds($select);
 	}
 
 	public function findChanged(Mailbox $mailbox, int $since): array {
@@ -644,4 +747,22 @@ class MessageMapper extends QBMapper {
 			->where($qb4->expr()->in('id', $qb4->createNamedParameter($ids, IQueryBuilder::PARAM_INT_ARRAY), IQueryBuilder::PARAM_INT_ARRAY));
 		$recipientsQuery->execute();
 	}
+
+	public function getIdForUid(Mailbox $mailbox, $uid): ?int {
+		$qb = $this->db->getQueryBuilder();
+
+		$select = $qb
+			->select('m.id')
+			->from($this->getTableName(), 'm')
+			->where(
+				$qb->expr()->eq('mailbox_id', $qb->createNamedParameter($mailbox->getId()), IQueryBuilder::PARAM_INT),
+				$qb->expr()->eq('uid', $qb->createNamedParameter($uid, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT)
+			);
+		$result = $select->execute();
+		$rows = $result->fetchAll();
+		if (empty($rows)) {
+			return null;
+		}
+		return (int) $rows[0]['id'];
+	}
 }
diff --git a/lib/Events/DraftSavedEvent.php b/lib/Events/DraftSavedEvent.php
index f8b6368da..677b4556c 100644
--- a/lib/Events/DraftSavedEvent.php
+++ b/lib/Events/DraftSavedEvent.php
@@ -26,6 +26,7 @@ declare(strict_types=1);
 namespace OCA\Mail\Events;
 
 use OCA\Mail\Account;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Model\NewMessageData;
 use OCP\EventDispatcher\Event;
 
@@ -37,16 +38,16 @@ class DraftSavedEvent extends Event {
 	/** @var NewMessageData */
 	private $newMessageData;
 
-	/** @var int|null */
-	private $draftUid;
+	/** @var Message|null */
+	private $draft;
 
 	public function __construct(Account $account,
 								NewMessageData $newMessageData,
-								?int $draftUid) {
+								?Message $draft) {
 		parent::__construct();
 		$this->account = $account;
 		$this->newMessageData = $newMessageData;
-		$this->draftUid = $draftUid;
+		$this->draft = $draft;
 	}
 
 	public function getAccount(): Account {
@@ -57,7 +58,7 @@ class DraftSavedEvent extends Event {
 		return $this->newMessageData;
 	}
 
-	public function getDraftUid(): ?int {
-		return $this->draftUid;
+	public function getDraft(): ?Message {
+		return $this->draft;
 	}
 }
diff --git a/lib/Events/MessageSentEvent.php b/lib/Events/MessageSentEvent.php
index 563467c4c..a2973cb8c 100644
--- a/lib/Events/MessageSentEvent.php
+++ b/lib/Events/MessageSentEvent.php
@@ -27,6 +27,7 @@ namespace OCA\Mail\Events;
 
 use Horde_Mime_Mail;
 use OCA\Mail\Account;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Model\IMessage;
 use OCA\Mail\Model\NewMessageData;
 use OCA\Mail\Model\RepliedMessageData;
@@ -43,8 +44,8 @@ class MessageSentEvent extends Event {
 	/** @var null|RepliedMessageData */
 	private $repliedMessageData;
 
-	/** @var int|null */
-	private $draftUid;
+	/** @var Message|null */
+	private $draft;
 
 	/** @var IMessage */
 	private $message;
@@ -55,14 +56,14 @@ class MessageSentEvent extends Event {
 	public function __construct(Account $account,
 								NewMessageData $newMessageData,
 								?RepliedMessageData $repliedMessageData,
-								?int $draftUid,
+								?Message $draft,
 								IMessage $message,
 								Horde_Mime_Mail $mail) {
 		parent::__construct();
 		$this->account = $account;
 		$this->newMessageData = $newMessageData;
 		$this->repliedMessageData = $repliedMessageData;
-		$this->draftUid = $draftUid;
+		$this->draft = $draft;
 		$this->message = $message;
 		$this->mail = $mail;
 	}
@@ -79,8 +80,8 @@ class MessageSentEvent extends Event {
 		return $this->repliedMessageData;
 	}
 
-	public function getDraftUid(): ?int {
-		return $this->draftUid;
+	public function getDraft(): ?Message {
+		return $this->draft;
 	}
 
 	public function getMessage(): IMessage {
diff --git a/lib/Events/SaveDraftEvent.php b/lib/Events/SaveDraftEvent.php
index 1f5590281..830bfe976 100644
--- a/lib/Events/SaveDraftEvent.php
+++ b/lib/Events/SaveDraftEvent.php
@@ -26,6 +26,7 @@ declare(strict_types=1);
 namespace OCA\Mail\Events;
 
 use OCA\Mail\Account;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Model\NewMessageData;
 use OCP\EventDispatcher\Event;
 
@@ -37,16 +38,16 @@ class SaveDraftEvent extends Event {
 	/** @var NewMessageData */
 	private $newMessageData;
 
-	/** @var int|null */
-	private $draftUid;
+	/** @var Message|null */
+	private $draft;
 
 	public function __construct(Account $account,
 								NewMessageData $newMessageData,
-								?int $draftUid) {
+								?Message $draft) {
 		parent::__construct();
 		$this->account = $account;
 		$this->newMessageData = $newMessageData;
-		$this->draftUid = $draftUid;
+		$this->draft = $draft;
 	}
 
 	public function getAccount(): Account {
@@ -57,7 +58,7 @@ class SaveDraftEvent extends Event {
 		return $this->newMessageData;
 	}
 
-	public function getDraftUid(): ?int {
-		return $this->draftUid;
+	public function getDraft(): ?Message {
+		return $this->draft;
 	}
 }
diff --git a/lib/IMAP/MessageMapper.php b/lib/IMAP/MessageMapper.php
index 2d0f3cee8..3b4fde341 100644
--- a/lib/IMAP/MessageMapper.php
+++ b/lib/IMAP/MessageMapper.php
@@ -364,14 +364,14 @@ class MessageMapper {
 	/**
 	 * @param Horde_Imap_Client_Socket $client
 	 * @param string $mailbox
-	 * @param int $id
+	 * @param int $uid
 	 *
 	 * @return string|null
 	 * @throws ServiceException
 	 */
 	public function getSource(Horde_Imap_Client_Socket $client,
 							  string $mailbox,
-							  int $id): ?string {
+							  int $uid): ?string {
 		$query = new Horde_Imap_Client_Fetch_Query();
 		$query->uid();
 		$query->fullText([
@@ -380,7 +380,7 @@ class MessageMapper {
 
 		try {
 			$result = iterator_to_array($client->fetch($mailbox, $query, [
-				'ids' => new Horde_Imap_Client_Ids($id),
+				'ids' => new Horde_Imap_Client_Ids($uid),
 			]), false);
 		} catch (Horde_Imap_Client_Exception $e) {
 			throw new ServiceException("Could not fetch message source: " . $e->getMessage(), $e->getCode(), $e);
@@ -399,13 +399,13 @@ class MessageMapper {
 
 	public function getHtmlBody(Horde_Imap_Client_Socket $client,
 								string $mailbox,
-								int $id): ?string {
+								int $uid): ?string {
 		$messageQuery = new Horde_Imap_Client_Fetch_Query();
 		$messageQuery->envelope();
 		$messageQuery->structure();
 
 		$result = $client->fetch($mailbox, $messageQuery, [
-			'ids' => new Horde_Imap_Client_Ids([$id]),
+			'ids' => new Horde_Imap_Client_Ids([$uid]),
 		]);
 
 		if (($message = $result->first()) === null) {
@@ -435,7 +435,7 @@ class MessageMapper {
 		}
 
 		$parts = $client->fetch($mailbox, $partsQuery, [
-			'ids' => new Horde_Imap_Client_Ids([$id]),
+			'ids' => new Horde_Imap_Client_Ids([$uid]),
 		]);
 
 		foreach ($parts as $part) {
@@ -456,12 +456,12 @@ class MessageMapper {
 
 	public function getRawAttachments(Horde_Imap_Client_Socket $client,
 									  string $mailbox,
-									  int $id): array {
+									  int $uid): array {
 		$messageQuery = new Horde_Imap_Client_Fetch_Query();
 		$messageQuery->structure();
 
 		$result = $client->fetch($mailbox, $messageQuery, [
-			'ids' => new Horde_Imap_Client_Ids([$id]),
+			'ids' => new Horde_Imap_Client_Ids([$uid]),
 		]);
 
 		if (($structureResult = $result->first()) === null) {
@@ -488,7 +488,7 @@ class MessageMapper {
 		}
 
 		$parts = $client->fetch($mailbox, $partsQuery, [
-			'ids' => new Horde_Imap_Client_Ids([$id]),
+			'ids' => new Horde_Imap_Client_Ids([$uid]),
 		]);
 		if (($messageData = $parts->first()) === null) {
 			throw new DoesNotExistException('Message does not exist');
diff --git a/lib/IMAP/Sync/Response.php b/lib/IMAP/Sync/Response.php
index 9e95b342e..d12625775 100644
--- a/lib/IMAP/Sync/Response.php
+++ b/lib/IMAP/Sync/Response.php
@@ -24,14 +24,15 @@ declare(strict_types=1);
 namespace OCA\Mail\IMAP\Sync;
 
 use JsonSerializable;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Model\IMAPMessage;
 
 class Response implements JsonSerializable {
 
-	/** @var IMAPMessage[] */
+	/** @var IMAPMessage|Message[] */
 	private $newMessages;
 
-	/** @var IMAPMessage[] */
+	/** @var IMAPMessage|Message[] */
 	private $changedMessages;
 
 	/** @var int[] */
@@ -39,8 +40,8 @@ class Response implements JsonSerializable {
 
 	/**
 	 * @param string $syncToken
-	 * @param IMAPMessage[] $newMessages
-	 * @param IMAPMessage[] $changedMessages
+	 * @param IMAPMessage|Message[] $newMessages
+	 * @param IMAPMessage|Message[] $changedMessages
 	 * @param int[] $vanishedMessageUids
 	 */
 	public function __construct(array $newMessages = [],
@@ -52,14 +53,14 @@ class Response implements JsonSerializable {
 	}
 
 	/**
-	 * @return IMAPMessage[]
+	 * @return IMAPMessage|Message[]
 	 */
 	public function getNewMessages(): array {
 		return $this->newMessages;
 	}
 
 	/**
-	 * @return IMAPMessage[]
+	 * @return IMAPMessage|Message[]
 	 */
 	public function getChangedMessages(): array {
 		return $this->changedMessages;
diff --git a/lib/IMAP/Threading/ThreadBuilder.php b/lib/IMAP/Threading/ThreadBuilder.php
index 72283423f..8053d045d 100644
--- a/lib/IMAP/Threading/ThreadBuilder.php
+++ b/lib/IMAP/Threading/ThreadBuilder.php
@@ -110,6 +110,9 @@ class ThreadBuilder {
 			// Step 1.C
 			//$parentId = $message->getReferences()[count($message->getReferences()) - 1] ?? null;
 			//$container->setParent($idTable[$parentId] ?? null);
+			if ($parent === $container) {
+				throw new \Exception("about to run into a nasty endless loop");
+			}
 			if ($parent === null || !$parent->hasAncestor($container)) {
 				$container->setParent($parent);
 			}
diff --git a/lib/Listener/DeleteDraftListener.php b/lib/Listener/DeleteDraftListener.php
index 0e76adec6..9758a0fa0 100644
--- a/lib/Listener/DeleteDraftListener.php
+++ b/lib/Listener/DeleteDraftListener.php
@@ -30,6 +30,7 @@ use Horde_Imap_Client_Exception;
 use OCA\Mail\Account;
 use OCA\Mail\Db\Mailbox;
 use OCA\Mail\Db\MailboxMapper;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Events\DraftSavedEvent;
 use OCA\Mail\Events\MessageSentEvent;
 use OCA\Mail\IMAP\IMAPClientFactory;
@@ -70,17 +71,18 @@ class DeleteDraftListener implements IEventListener {
 	}
 
 	public function handle(Event $event): void {
-		if ($event instanceof DraftSavedEvent && $event->getDraftUid() !== null) {
-			$this->deleteDraft($event->getAccount(), $event->getDraftUid());
-		} elseif ($event instanceof MessageSentEvent && $event->getDraftUid() !== null) {
-			$this->deleteDraft($event->getAccount(), $event->getDraftUid());
+		if ($event instanceof DraftSavedEvent && $event->getDraft() !== null) {
+			$this->deleteDraft($event->getAccount(), $event->getDraft());
+		} elseif ($event instanceof MessageSentEvent && $event->getDraft() !== null) {
+			$this->deleteDraft($event->getAccount(), $event->getDraft());
 		}
 	}
 
 	/**
-	 * @param DraftSavedEvent $event
+	 * @param Account $account
+	 * @param Message $draft
 	 */
-	private function deleteDraft(Account $account, int $draftUid): void {
+	private function deleteDraft(Account $account, Message $draft): void {
 		$client = $this->imapClientFactory->getClient($account);
 		$draftsMailbox = $this->getDraftsMailbox($account);
 
@@ -88,7 +90,7 @@ class DeleteDraftListener implements IEventListener {
 			$this->messageMapper->addFlag(
 				$client,
 				$draftsMailbox,
-				$draftUid,
+				$draft->getUid(), // TODO: the UID could be from another mailbox
 				Horde_Imap_Client::FLAG_DELETED
 			);
 		} catch (Horde_Imap_Client_Exception $e) {
diff --git a/lib/Mailbox.php b/lib/Mailbox.php
index 09daef680..5aecf8330 100644
--- a/lib/Mailbox.php
+++ b/lib/Mailbox.php
@@ -295,12 +295,13 @@ class Mailbox implements IMailBox {
 	}
 
 	/**
-	 * @param int $messageId
+	 * @param int $messageUid
 	 * @param string $attachmentId
+	 *
 	 * @return Attachment
 	 */
-	public function getAttachment(int $messageId, string $attachmentId): Attachment {
-		return new Attachment($this->conn, $this->mailBox, $messageId, $attachmentId);
+	public function getAttachment(int $messageUid, string $attachmentId): Attachment {
+		return new Attachment($this->conn, $this->mailBox, $messageUid, $attachmentId);
 	}
 
 	/**
diff --git a/lib/Model/IMAPMessage.php b/lib/Model/IMAPMessage.php
index 1dae7a1d0..8b7ae12a3 100644
--- a/lib/Model/IMAPMessage.php
+++ b/lib/Model/IMAPMessage.php
@@ -48,7 +48,6 @@ use OCA\Mail\Service\Html;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\Files\File;
 use OCP\Files\SimpleFS\ISimpleFile;
-use function base64_encode;
 use function in_array;
 use function mb_convert_encoding;
 
@@ -422,15 +421,17 @@ class IMAPMessage implements IMessage, JsonSerializable {
 	}
 
 	/**
+	 * @param int $id
+	 *
 	 * @return array
 	 */
-	public function getFullMessage(int $accountId, string $mailbox, int $id): array {
+	public function getFullMessage(int $id): array {
 		$mailBody = $this->plainMessage;
 
 		$data = $this->jsonSerialize();
 		if ($this->hasHtmlMessage) {
 			$data['hasHtmlBody'] = true;
-			$data['body'] = $this->getHtmlBody($accountId, $mailbox, $id);
+			$data['body'] = $this->getHtmlBody($id);
 		} else {
 			$mailBody = $this->htmlService->convertLinks($mailBody);
 			list($mailBody, $signature) = $this->htmlService->parseMailBody($mailBody);
@@ -462,17 +463,13 @@ class IMAPMessage implements IMessage, JsonSerializable {
 	}
 
 	/**
-	 * @param int $accountId
-	 * @param string $folderId
-	 * @param int $messageId
+	 * @param int $id
 	 *
 	 * @return string
 	 */
-	public function getHtmlBody(int $accountId, string $folderId, int $messageId): string {
+	public function getHtmlBody(int $id): string {
 		return $this->htmlService->sanitizeHtmlMailBody($this->htmlMessage, [
-			'accountId' => $accountId,
-			'folderId' => base64_encode($folderId),
-			'messageId' => $messageId,
+			'id' => $id,
 		], function ($cid) {
 			$match = array_filter($this->attachments,
 				function ($a) use ($cid) {
diff --git a/lib/Service/AccountService.php b/lib/Service/AccountService.php
index 83a4a6977..36fbf11a1 100644
--- a/lib/Service/AccountService.php
+++ b/lib/Service/AccountService.php
@@ -89,25 +89,25 @@ class AccountService {
 
 	/**
 	 * @param string $uid
-	 * @param int $accountId
+	 * @param int $id
 	 *
 	 * @return Account
 	 * @throws ClientException
 	 */
-	public function find(string $uid, int $accountId): Account {
+	public function find(string $uid, int $id): Account {
 		if ($this->accounts !== null) {
 			foreach ($this->accounts as $account) {
-				if ($account->getId() === $accountId) {
+				if ($account->getId() === $id) {
 					return $account;
 				}
 			}
-			throw new ClientException("Account $accountId does not exist or you don\'t have permission to access it");
+			throw new ClientException("Account $id does not exist or you don\'t have permission to access it");
 		}
 
 		try {
-			return new Account($this->mapper->find($uid, $accountId));
+			return new Account($this->mapper->find($uid, $id));
 		} catch (DoesNotExistException $e) {
-			throw new ClientException("Account $accountId does not exist or you don\'t have permission to access it");
+			throw new ClientException("Account $id does not exist or you don\'t have permission to access it");
 		}
 	}
 
diff --git a/lib/Service/IMailBox.php b/lib/Service/IMailBox.php
index 093e3d7f1..d75c5c562 100644
--- a/lib/Service/IMailBox.php
+++ b/lib/Service/IMailBox.php
@@ -47,11 +47,12 @@ interface IMailBox {
 	public function getMessage(int $id, bool $loadHtmlMessageBody = false);
 
 	/**
-	 * @param int $messageId
+	 * @param int $messageUid
 	 * @param string $attachmentId
+	 *
 	 * @return Attachment
 	 */
-	public function getAttachment(int $messageId, string $attachmentId): Attachment;
+	public function getAttachment(int $messageUid, string $attachmentId): Attachment;
 
 	/**
 	 * @param int $flags
diff --git a/lib/Service/MailManager.php b/lib/Service/MailManager.php
index 08cceb812..09d04dcc3 100644
--- a/lib/Service/MailManager.php
+++ b/lib/Service/MailManager.php
@@ -30,6 +30,7 @@ use OCA\Mail\Account;
 use OCA\Mail\Contracts\IMailManager;
 use OCA\Mail\Db\Mailbox;
 use OCA\Mail\Db\MailboxMapper;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Db\MessageMapper as DbMessageMapper;
 use OCA\Mail\Events\BeforeMessageDeletedEvent;
 use OCA\Mail\Events\MessageDeletedEvent;
@@ -100,6 +101,14 @@ class MailManager implements IMailManager {
 		$this->eventDispatcher = $eventDispatcher;
 	}
 
+	public function getMailbox(string $uid, int $id): Mailbox {
+		try {
+			return $this->mailboxMapper->findByUid($id, $uid);
+		} catch (DoesNotExistException $e) {
+			throw new ClientException("Mailbox $id does not exist", 0, $e);
+		}
+	}
+
 	/**
 	 * @param Account $account
 	 *
@@ -116,10 +125,10 @@ class MailManager implements IMailManager {
 	 * @param Account $account
 	 * @param string $name
 	 *
-	 * @return Folder
+	 * @return Mailbox
 	 * @throws ServiceException
 	 */
-	public function createFolder(Account $account, string $name): Folder {
+	public function createMailbox(Account $account, string $name): Mailbox {
 		$client = $this->imapClientFactory->getClient($account);
 
 		$folder = $this->folderMapper->createFolder($client, $account, $name);
@@ -132,30 +141,33 @@ class MailManager implements IMailManager {
 
 		$this->mailboxSync->sync($account, true);
 
-		return $folder;
+		return $this->mailboxMapper->find($account, $name);
 	}
 
 	/**
 	 * @param Account $account
-	 * @param string $folderId
+	 * @param Mailbox $mailbox
 	 *
 	 * @return FolderStats
+	 * @throws Horde_Imap_Client_Exception
 	 */
-	public function getFolderStats(Account $account, string $folderId): FolderStats {
+	public function getMailboxStats(Account $account, Mailbox $mailbox): FolderStats {
 		$client = $this->imapClientFactory->getClient($account);
 
-		return $this->folderMapper->getFoldersStatusAsObject($client, $folderId);
+		return $this->folderMapper->getFoldersStatusAsObject($client, $mailbox->getName());
 	}
 
-	public function getMessage(Account $account, string $mailbox, int $id, bool $loadBody = false): IMAPMessage {
+	public function getImapMessage(Account $account,
+								   Mailbox $mailbox,
+								   int $uid,
+								   bool $loadBody = false): IMAPMessage {
 		$client = $this->imapClientFactory->getClient($account);
-		$mailbox = $this->mailboxMapper->find($account, $mailbox);
 
 		try {
 			return $this->imapMessageMapper->find(
 				$client,
 				$mailbox->getName(),
-				$id,
+				$uid,
 				$loadBody
 			);
 		} catch (Horde_Imap_Client_Exception|DoesNotExistException $e) {
@@ -167,24 +179,32 @@ class MailManager implements IMailManager {
 		return $this->dbMessageMapper->findThread($account, $messageId);
 	}
 
+	public function getMessageIdForUid(Mailbox $mailbox, $uid): ?int {
+		return $this->dbMessageMapper->getIdForUid($mailbox, $uid);
+	}
+
+	public function getMessage(string $uid, int $id): Message {
+		return $this->dbMessageMapper->findByUserId($uid, $id);
+	}
+
 	/**
 	 * @param Account $account
 	 * @param string $mb
-	 * @param int $id
+	 * @param int $uid
 	 *
 	 * @return string
 	 *
 	 * @throws ClientException
 	 * @throws ServiceException
 	 */
-	public function getSource(Account $account, string $mailbox, int $id): string {
+	public function getSource(Account $account, string $mailbox, int $uid): ?string {
 		$client = $this->imapClientFactory->getClient($account);
 
 		try {
 			return $this->imapMessageMapper->getSource(
 				$client,
 				$mailbox,
-				$id
+				$uid
 			);
 		} catch (Horde_Imap_Client_Exception|DoesNotExistException $e) {
 			throw new ServiceException("Could not load message", 0, $e);
@@ -194,7 +214,7 @@ class MailManager implements IMailManager {
 	/**
 	 * @param Account $sourceAccount
 	 * @param string $sourceFolderId
-	 * @param int $messageId
+	 * @param int $uid
 	 * @param Account $destinationAccount
 	 * @param string $destFolderId
 	 *
@@ -204,7 +224,7 @@ class MailManager implements IMailManager {
 	 */
 	public function moveMessage(Account $sourceAccount,
 								string $sourceFolderId,
-								int $messageId,
+								int $uid,
 								Account $destinationAccount,
 								string $destFolderId) {
 		if ($sourceAccount->getId() === $destinationAccount->getId()) {
@@ -212,7 +232,7 @@ class MailManager implements IMailManager {
 				$sourceAccount,
 				$sourceFolderId,
 				$destFolderId,
-				$messageId
+				$uid
 			);
 		} else {
 			throw new ServiceException('It is not possible to move across accounts yet');
@@ -284,10 +304,10 @@ class MailManager implements IMailManager {
 		$this->imapMessageMapper->move($client, $sourceFolderId, $messageId, $destFolderId);
 	}
 
-	public function markFolderAsRead(Account $account, string $folderId): void {
+	public function markFolderAsRead(Account $account, Mailbox $mailbox): void {
 		$client = $this->imapClientFactory->getClient($account);
 
-		$this->imapMessageMapper->markAllRead($client, $folderId);
+		$this->imapMessageMapper->markAllRead($client, $mailbox->getName());
 	}
 
 	public function flagMessage(Account $account, string $mailbox, int $uid, string $flag, bool $value): void {
@@ -371,18 +391,14 @@ class MailManager implements IMailManager {
 
 	/**
 	 * @param Account $account
-	 * @param string $folderId
+	 * @param Mailbox $mailbox
+	 *
 	 * @throws ServiceException
 	 */
 	public function deleteMailbox(Account $account,
-								  string $folderId): void {
-		try {
-			$mailbox = $this->mailboxMapper->find($account, $folderId);
-		} catch (DoesNotExistException $e) {
-			throw new ServiceException("Source mailbox $folderId does not exist", 0, $e);
-		}
+								  Mailbox $mailbox): void {
 		$client = $this->imapClientFactory->getClient($account);
-		$this->folderMapper->delete($client, $folderId);
+		$this->folderMapper->delete($client, $mailbox->getName());
 		$this->mailboxMapper->delete($mailbox);
 	}
 }
diff --git a/lib/Service/MailTransmission.php b/lib/Service/MailTransmission.php
index 9db9c1d4a..e8ff9d135 100644
--- a/lib/Service/MailTransmission.php
+++ b/lib/Service/MailTransmission.php
@@ -39,6 +39,7 @@ use OCA\Mail\Contracts\IAttachmentService;
 use OCA\Mail\Contracts\IMailTransmission;
 use OCA\Mail\Db\Alias;
 use OCA\Mail\Db\MailboxMapper;
+use OCA\Mail\Db\Message;
 use OCA\Mail\Events\DraftSavedEvent;
 use OCA\Mail\Events\MessageSentEvent;
 use OCA\Mail\Events\SaveDraftEvent;
@@ -102,22 +103,10 @@ class MailTransmission implements IMailTransmission {
 		$this->logger = $logger;
 	}
 
-	/**
-	 * Send a new message or reply to an existing one
-	 *
-	 * @param NewMessageData $messageData
-	 * @param RepliedMessageData $replyData
-	 * @param Alias|null $alias
-	 * @param int|null $draftUID
-	 *
-	 * @throws ServiceException
-	 *
-	 * @return void
-	 */
 	public function sendMessage(NewMessageData $messageData,
 								RepliedMessageData $replyData = null,
 								Alias $alias = null,
-								int $draftUID = null) {
+								Message $draft = null) {
 		$account = $messageData->getAccount();
 
 		if ($replyData !== null) {
@@ -178,17 +167,22 @@ class MailTransmission implements IMailTransmission {
 
 		$this->eventDispatcher->dispatch(
 			MessageSentEvent::class,
-			new MessageSentEvent($account, $messageData, $replyData, $draftUID, $message, $mail)
+			new MessageSentEvent($account, $messageData, $replyData, $draft, $message, $mail)
 		);
 	}
 
 	/**
+	 * @param NewMessageData $message
+	 * @param Message|null $previousDraft
+	 *
+	 * @return array
+	 *
 	 * @throws ServiceException
 	 */
-	public function saveDraft(NewMessageData $message, int $draftUID = null): int {
+	public function saveDraft(NewMessageData $message, Message $previousDraft = null): array {
 		$this->eventDispatcher->dispatch(
 			SaveDraftEvent::class,
-			new SaveDraftEvent($message->getAccount(), $message, $draftUID)
+			new SaveDraftEvent($message->getAccount(), $message, $previousDraft)
 		);
 
 		$account = $message->getAccount();
@@ -243,10 +237,10 @@ class MailTransmission implements IMailTransmission {
 
 		$this->eventDispatcher->dispatch(
 			DraftSavedEvent::class,
-			new DraftSavedEvent($account, $message, $draftUID)
+			new DraftSavedEvent($account, $message, $previousDraft)
 		);
 
-		return $newUid;
+		return [$account, $draftsMailbox, $newUid];
 	}
 
 	private function buildReplyMessage(Account $account,
diff --git a/lib/Service/Search/MailSearch.php b/lib/Service/Search/MailSearch.php
index cead97321..85b021704 100644
--- a/lib/Service/Search/MailSearch.php
+++ b/lib/Service/Search/MailSearch.php
@@ -75,32 +75,26 @@ class MailSearch implements IMailSearch {
 		$this->logger = $logger;
 	}
 
-	public function findMessage(Account $account, string $mailboxName, int $uid): Message {
-		try {
-			$mailbox = $this->mailboxMapper->find($account, $mailboxName);
-		} catch (DoesNotExistException $e) {
-			throw new ServiceException('Mailbox does not exist', 0, $e);
-		}
-
-		$messages = $this->previewEnhancer->process(
+	public function findMessage(Account $account,
+								Mailbox $mailbox,
+								Message $message): Message {
+		$processed = $this->previewEnhancer->process(
 			$account,
 			$mailbox,
-			$this->messageMapper->findByUids(
-				$mailbox,
-				[$uid]
-			)
+			[$message]
 		);
-		if (empty($messages)) {
+		if (empty($processed)) {
 			throw new DoesNotExistException("Message does not exist");
 		}
-		return $messages[0];
+		return $processed[0];
 	}
 
 	/**
 	 * @param Account $account
-	 * @param string $mailboxName
+	 * @param Mailbox $mailbox
 	 * @param string|null $filter
 	 * @param int|null $cursor
+	 * @param int|null $limit
 	 *
 	 * @return Message[]
 	 *
@@ -108,16 +102,10 @@ class MailSearch implements IMailSearch {
 	 * @throws ServiceException
 	 */
 	public function findMessages(Account $account,
-								 string $mailboxName,
+								 Mailbox $mailbox,
 								 ?string $filter,
 								 ?int $cursor,
 								 ?int $limit): array {
-		try {
-			$mailbox = $this->mailboxMapper->find($account, $mailboxName);
-		} catch (DoesNotExistException $e) {
-			throw new ServiceException('Mailbox does not exist', 0, $e);
-		}
-
 		if ($mailbox->hasLocks()) {
 			throw MailboxLockedException::from($mailbox);
 		}
@@ -141,9 +129,8 @@ class MailSearch implements IMailSearch {
 		return $this->previewEnhancer->process(
 			$account,
 			$mailbox,
-			$this->messageMapper->findByUids(
-				$mailbox,
-				$this->getUids($account, $mailbox, $query, $limit)
+			$this->messageMapper->findByIds(
+				$this->getIds($account, $mailbox, $query, $limit)
 			)
 		);
 	}
@@ -153,9 +140,9 @@ class MailSearch implements IMailSearch {
 	 *
 	 * @throws ServiceException
 	 */
-	private function getUids(Account $account, Mailbox $mailbox, SearchQuery $query, ?int $limit): array {
+	private function getIds(Account $account, Mailbox $mailbox, SearchQuery $query, ?int $limit): array {
 		if (empty($query->getTextTokens())) {
-			return $this->messageMapper->findUidsByQuery($mailbox, $query, $limit);
+			return $this->messageMapper->findIdsByQuery($mailbox, $query, $limit);
 		}
 
 		$fromImap = $this->imapSearchProvider->findMatches(
@@ -163,6 +150,6 @@ class MailSearch implements IMailSearch {
 			$mailbox,
 			$query
 		);
-		return $this->messageMapper->findUidsByQuery($mailbox, $query, $limit, $fromImap);
+		return $this->messageMapper->findIdsByQuery($mailbox, $query, $limit, $fromImap);
 	}
 }
diff --git a/lib/Service/Sync/SyncService.php b/lib/Service/Sync/SyncService.php
index 484ce597b..385a66b84 100644
--- a/lib/Service/Sync/SyncService.php
+++ b/lib/Service/Sync/SyncService.php
@@ -38,10 +38,8 @@ use OCA\Mail\IMAP\PreviewEnhancer;
 use OCA\Mail\IMAP\Sync\Response;
 use OCA\Mail\Service\Search\FilterStringParser;
 use OCA\Mail\Service\Search\SearchQuery;
-use OCP\AppFramework\Db\DoesNotExistException;
 use function array_diff;
 use function array_map;
-use function end;
 
 class SyncService {
 
@@ -74,46 +72,36 @@ class SyncService {
 
 	/**
 	 * @param Account $account
-	 * @param string $mailboxId
+	 * @param Mailbox $mailbox
 	 *
 	 * @throws MailboxLockedException
 	 * @throws ServiceException
 	 */
 	public function clearCache(Account $account,
-							   string $mailboxId): void {
-		try {
-			$mailbox = $this->mailboxMapper->find($account, $mailboxId);
-		} catch (DoesNotExistException $e) {
-			throw new ServiceException('Mailbox to sync does not exist in the database', 0, $e);
-		}
-
+							   Mailbox $mailbox): void {
 		$this->synchronizer->clearCache($account, $mailbox);
 	}
 
 	/**
 	 * @param Account $account
-	 * @param string $mailboxId
+	 * @param Mailbox $mailbox
 	 * @param int $criteria
-	 * @param array $knownUids
+	 * @param int[] $knownIds
 	 * @param bool $partialOnly
 	 *
+	 * @param string|null $filter
+	 *
 	 * @return Response
 	 * @throws ClientException
 	 * @throws MailboxNotCachedException
 	 * @throws ServiceException
 	 */
 	public function syncMailbox(Account $account,
-								string $mailboxId,
+								Mailbox $mailbox,
 								int $criteria,
-								array $knownUids,
+								array $knownIds,
 								bool $partialOnly,
 								string $filter = null): Response {
-		try {
-			$mailbox = $this->mailboxMapper->find($account, $mailboxId);
-		} catch (DoesNotExistException $e) {
-			throw new ServiceException('Mailbox to sync does not exist in the database', 0, $e);
-		}
-
 		if ($partialOnly && !$mailbox->isCached()) {
 			throw MailboxNotCachedException::from($mailbox);
 		}
@@ -122,52 +110,57 @@ class SyncService {
 			$account,
 			$mailbox,
 			$criteria,
-			$knownUids,
+			$this->messageMapper->findUidsForIds($mailbox, $knownIds),
 			!$partialOnly
 		);
 
 		$query = $filter === null ? null : $this->filterStringParser->parse($filter);
-
-		return $this->getDatabaseSyncChanges($account, $mailbox, $knownUids, $query);
+		return $this->getDatabaseSyncChanges(
+			$account,
+			$mailbox,
+			$knownIds,
+			$query
+		);
 	}
 
 	/**
 	 * @param Account $account
 	 * @param Mailbox $mailbox
-	 * @param array $knownUids
+	 * @param int[] $knownIds
 	 * @param SearchQuery $query
 	 *
 	 * @return Response
 	 * @todo does not work with text token search queries
 	 *
 	 */
-	private function getDatabaseSyncChanges(Account $account, Mailbox $mailbox, array $knownUids, ?SearchQuery $query): Response {
-		if (empty($knownUids)) {
-			$newUids = $this->messageMapper->findAllUids($mailbox);
+	private function getDatabaseSyncChanges(Account $account,
+											Mailbox $mailbox,
+											array $knownIds,
+											?SearchQuery $query): Response {
+		if (empty($knownIds)) {
+			$newIds = $this->messageMapper->findAllIds($mailbox);
 		} else {
-			sort($knownUids, SORT_NUMERIC);
-			$last = end($knownUids);
-			$newUids = $this->messageMapper->findNewUids($mailbox, $last);
+			$newIds = $this->messageMapper->findNewIds($mailbox, $knownIds);
 		}
 
 		if ($query !== null) {
 			// Filter new messages to those that also match the current filter
-			$newUids = $this->messageMapper->findUidsByQuery($mailbox, $query, null, $newUids);
+			$newIds = $this->messageMapper->findIdsByQuery($mailbox, $query, null, $newIds);
 		}
-		$new = $this->messageMapper->findByUids($mailbox, $newUids);
+		$new = $this->messageMapper->findByIds($newIds);
 
 		// TODO: $changed = $this->messageMapper->findChanged($mailbox, $uids);
 		if ($query !== null) {
-			$changedUids = $this->messageMapper->findUidsByQuery($mailbox, $query, null, $knownUids);
+			$changedIds = $this->messageMapper->findIdsByQuery($mailbox, $query, null, $knownIds);
 		} else {
-			$changedUids = $knownUids;
+			$changedIds = $knownIds;
 		}
-		$changed = $this->messageMapper->findByUids($mailbox, $changedUids);
+		$changed = $this->messageMapper->findByIds($changedIds);
 
-		$stillKnownUids = array_map(static function (Message $msg) {
-			return $msg->getUid();
+		$stillKnownIds = array_map(static function (Message $msg) {
+			return $msg->getId();
 		}, $changed);
-		$vanished = array_values(array_diff($knownUids, $stillKnownUids));
+		$vanished = array_values(array_diff($knownIds, $stillKnownIds));
 
 		return new Response(
 			$this->previewEnhancer->process($account, $mailbox, $new),