Add an appointment booking page

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

appinfo/routes.php

@@ -36,6 +36,9 @@ return [
 		['name' => 'view#index', 'url' => '/{view}/{timeRange}/edit/{mode}/{objectId}/{recurrenceId}', 'verb' => 'GET', 'requirements' => ['view' => 'timeGridDay|timeGridWeek|dayGridMonth|listMonth'], 'postfix' => 'view.timerange.edit'],
 		// Appointments
 		['name' => 'appointment#index', 'url' => '/appointments/{userId}', 'verb' => 'GET'],
+		['name' => 'appointment#show', 'url' => '/appointment/{token}', 'verb' => 'GET'],
+		['name' => 'booking#getBookableSlots', 'url' => '/appointment/{appointmentConfigId}/slots', 'verb' => 'GET'],
+		['name' => 'booking#bookSlot', 'url' => '/appointment/{appointmentConfigId}/book', 'verb' => 'POST'],
 		// Public views
 		['name' => 'publicView#public_index_with_branding', 'url' => '/p/{token}', 'verb' => 'GET'],
 		['name' => 'publicView#public_index_with_branding', 'url' => '/p/{token}/{view}/{timeRange}', 'verb' => 'GET', 'postfix' => 'publicview.timerange'],

lib/Controller/AppointmentController.php

@@ -27,13 +27,17 @@ namespace OCA\Calendar\Controller;
 
 use OCA\Calendar\AppInfo\Application;
 use OCA\Calendar\Db\AppointmentConfig;
+use OCA\Calendar\Exception\ClientException;
+use OCA\Calendar\Exception\ServiceException;
 use OCA\Calendar\Service\Appointments\AppointmentConfigService;
 use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\Response;
 use OCP\AppFramework\Http\TemplateResponse;
 use OCP\AppFramework\Services\IInitialState;
 use OCP\IRequest;
 use OCP\IUserManager;
+use RuntimeException;
 use function array_filter;
 
 class AppointmentController extends Controller {
@@ -97,4 +101,49 @@ class AppointmentController extends Controller {
 			TemplateResponse::RENDER_AS_PUBLIC
 		);
 	}
+
+	/**
+	 * @PublicPage
+	 * @NoAdminRequired
+	 * @NoCSRFRequired
+	 *
+	 * @return Response
+	 */
+	public function show(string $token): Response {
+		try {
+			$config = $this->configService->findByToken($token);
+		} catch (ClientException $e) {
+			if ($e->getHttpCode() === Http::STATUS_NOT_FOUND) {
+				return new TemplateResponse(
+					Application::APP_ID,
+					'appointments/404-booking',
+					[],
+					TemplateResponse::RENDER_AS_GUEST
+				);
+			}
+		}
+
+		$user = $this->userManager->get($config->getUserId());
+		if ($user === null) {
+			throw new ServiceException("Appointment config $token does not belong to a valid user");
+		}
+		$this->initialState->provideInitialState(
+			'userInfo',
+			[
+				'uid' => $user->getUID(),
+				'displayName' => $user->getDisplayName(),
+			],
+		);
+		$this->initialState->provideInitialState(
+			'config',
+			$config
+		);
+
+		return new TemplateResponse(
+			Application::APP_ID,
+			'appointments/booking',
+			[],
+			TemplateResponse::RENDER_AS_PUBLIC
+		);
+	}
 }

lib/Controller/BookingController.php

@@ -24,24 +24,17 @@ declare(strict_types=1);
  */
 namespace OCA\Calendar\Controller;
 
+use DateTimeImmutable;
+use DateTimeZone;
 use OCA\Calendar\Exception\ServiceException;
 use OCA\Calendar\Http\JsonResponse;
 use OCA\Calendar\Service\Appointments\AppointmentConfigService;
-use OCA\Calendar\Service\Appointments\Booking;
 use OCA\Calendar\Service\Appointments\BookingService;
 use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http;
 use OCP\AppFramework\Utility\ITimeFactory;
-use OCP\Calendar\IManager;
-use OCP\IConfig;
-use OCP\IInitialStateService;
 use OCP\IRequest;
-use OCP\IURLGenerator;
 
-/**
- * Class PublicViewController
- *
- * @package OCA\Calendar\Controller
- */
 class BookingController extends Controller {
 
 	/** @var BookingService */
@@ -53,22 +46,11 @@ class BookingController extends Controller {
 	/** @var AppointmentConfigService */
 	private $appointmentConfigService;
 
-	/** @var IManager */
-	private $manager;
-
-	/**
-	 * @param string $appName
-	 * @param IRequest $request an instance of the request
-	 * @param IConfig $config
-	 * @param IInitialStateService $initialStateService
-	 * @param IURLGenerator $urlGenerator
-	 */
 	public function __construct(string                   $appName,
 								IRequest                 $request,
 								ITimeFactory             $timeFactory,
 								BookingService           $bookingService,
-								AppointmentConfigService $appointmentConfigService,
-								IManager                 $manager) {
+								AppointmentConfigService $appointmentConfigService) {
 		parent::__construct($appName, $request);
 
 		$this->bookingService = $bookingService;
@@ -77,30 +59,63 @@ class BookingController extends Controller {
 	}
 
 	/**
-	 * @throws ServiceException
-	 * @throws \JsonException
+	 * @NoAdminRequired
+	 * @PublicPage
+	 *
+	 * @param int $appointmentConfigId
+	 * @param int $startTime UNIX time stamp for the start time in UTC
+	 * @param int $endTime UNIX time stamp for the start time in UTC
+	 * @param string $timeZone
+	 *
+	 * @return JsonResponse
 	 */
-	public function getBookableSlots(int $appointmentConfigId, int $unixStartTime, int $unixEndTime) {
+	public function getBookableSlots(int $appointmentConfigId,
+									 int $startTime,
+									 int $endTime,
+									 string $timeZone): JsonResponse {
+		// Convert the timestamps to the beginning and end of the respective day in the specified timezone
+		$tz = new DateTimeZone($timeZone);
+		$startTimeInTz = (new DateTimeImmutable())
+			->setTimestamp($startTime)
+			->setTimezone($tz)
+			->setTime(0, 0)
+			->getTimestamp();
+		$endTimeInTz = (new DateTimeImmutable())
+			->setTimestamp($endTime)
+			->setTimezone($tz)
+			->setTime(23, 59, 59)
+			->getTimestamp();
+
+		if ($startTimeInTz > $endTimeInTz) {
+			return JsonResponse::fail('Invalid time range', Http::STATUS_UNPROCESSABLE_ENTITY);
+		}
 		// rate limit this to only allow ranges between 0 to 7 days
-		if (ceil(($unixEndTime - $unixStartTime) / 86400) > 7) {
-			return JsonResponse::error('Date Range too large.', 403);
+		if (ceil(($endTimeInTz - $startTimeInTz) / 86400) > 7) {
+			return JsonResponse::fail('Date Range too large.', Http::STATUS_UNPROCESSABLE_ENTITY);
+		}
+		$now = $this->timeFactory->getTime();
+		if ($now > $endTimeInTz) {
+			return JsonResponse::fail('Slot time range must be in the future', Http::STATUS_UNPROCESSABLE_ENTITY);
 		}
 
-		if ($this->timeFactory->getTime() > $unixStartTime || $this->timeFactory->getTime() > $unixEndTime) {
-			throw  new ServiceException('Booking time must be in the future', 403);
+		try {
+			$config = $this->appointmentConfigService->findById($appointmentConfigId);
+		} catch (ServiceException $e) {
+			return JsonResponse::fail(null, Http::STATUS_NOT_FOUND);
 		}
-
-		$appointmentConfig = $this->appointmentConfigService->findById($appointmentConfigId);
-		$booking = new Booking($appointmentConfig, $unixStartTime, $unixEndTime);
-		$data = $this->bookingService->getSlots($booking);
-		return JsonResponse::success($data);
+		return JsonResponse::success(
+			$this->bookingService->getAvailableSlots($config, $startTimeInTz, $endTimeInTz)
+		);
 	}
 
-	/**
-	 * @param string $calendarData
-	 */
-	public function bookSlot(string $calendarData) {
-		$this->bookingService->book($calendarData);
+	public function bookSlot(int $appointmentConfigId,
+							 int $start,
+							 string $name,
+							 string $email,
+							 string $description): JsonResponse {
+		return JsonResponse::success();
+
+		//$this->bookingService->book($calendarData);
 		return JsonResponse::success();
 	}
 }

lib/Db/AppointmentConfig.php

@@ -29,6 +29,7 @@ namespace OCA\Calendar\Db;
 
 use JsonSerializable;
 use OCP\AppFramework\Db\Entity;
+use function json_decode;
 
 /**
  * @method int getId()
@@ -50,7 +51,7 @@ use OCP\AppFramework\Db\Entity;
  * @method string|null getCalendarFreebusyUris()
  * @method void setCalendarFreebusyUris(?string $freebusyUris)
  * @method string getAvailability()
- * @method void setAvailability(string $availability)
+ * @method void setAvailability(?string $availability)
  * @method int getLength()
  * @method void setLength(int $length)
  * @method int getIncrement()
@@ -90,7 +91,7 @@ class AppointmentConfig extends Entity implements JsonSerializable {
 	/** @var string|null */
 	protected $calendarFreebusyUris;
 
-	/** @var string */
+	/** @var string|null */
 	protected $availability;
 
 	/** @var int */
@@ -132,10 +133,14 @@ class AppointmentConfig extends Entity implements JsonSerializable {
 	 *
 	 * @return string
 	 */
-	public function getPrincipalUri() : string {
+	public function getPrincipalUri(): string {
 		return 'principals/users/' . $this->userId;
 	}
 
+	public function getCalendarFreebusyUrisAsArray(): array {
+		return json_decode($this->getCalendarFreebusyUris(), true, 512, JSON_THROW_ON_ERROR);
+	}
+
 	public function jsonSerialize() {
 		return [
 			'id' => $this->id,

lib/Db/AppointmentConfigMapper.php

@@ -75,9 +75,7 @@ class AppointmentConfigMapper extends QBMapper {
 	/**
 	 * @param string $token
 	 * @return AppointmentConfig
-	 * @throws DbException
 	 * @throws DoesNotExistException
-	 * @throws MultipleObjectsReturnedException
 	 */
 	public function findByToken(string $token) : AppointmentConfig {
 		$qb = $this->db->getQueryBuilder();

lib/Exception/ClientException.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\Calendar\Exception;
+
+use Exception;
+use Throwable;
+
+class ClientException extends Exception {
+
+	/** @var int|null */
+	private $httpCode;
+
+	public function __construct($message = "",
+								$code = 0,
+								Throwable $previous = null,
+								int $httpCode = null) {
+		parent::__construct($message, $code, $previous);
+		$this->httpCode = $httpCode;
+	}
+
+	public function getHttpCode(): ?int {
+		return $this->httpCode;
+	}
+}

lib/Service/Appointments/AppointmentConfigService.php

@@ -1,6 +1,7 @@
 <?php
 
 declare(strict_types=1);
+
 /**
  * Calendar App
  *
@@ -22,13 +23,16 @@ declare(strict_types=1);
  * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
+
 namespace OCA\Calendar\Service\Appointments;
 
 use OCA\Calendar\Db\AppointmentConfig;
 use OCA\Calendar\Db\AppointmentConfigMapper;
+use OCA\Calendar\Exception\ClientException;
 use OCA\Calendar\Exception\ServiceException;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\AppFramework\Db\MultipleObjectsReturnedException;
+use OCP\AppFramework\Http;
 use OCP\DB\Exception as DbException;
 
 class AppointmentConfigService {
@@ -60,6 +64,7 @@ class AppointmentConfigService {
 	/**
 	 * @param int $id
 	 * @param string $userId
+	 *
 	 * @throws ServiceException
 	 */
 	public function delete(int $id, string $userId): void {
@@ -72,6 +77,7 @@ class AppointmentConfigService {
 
 	/**
 	 * @param AppointmentConfig $appointmentConfig
+	 *
 	 * @return AppointmentConfig
 	 * @throws ServiceException
 	 */
@@ -85,32 +91,53 @@ class AppointmentConfigService {
 
 	/**
 	 * @param int $id
+	 *
 	 * @return AppointmentConfig
 	 * @throws ServiceException
 	 */
 	public function findById(int $id): AppointmentConfig {
 		try {
 			return $this->mapper->findById($id);
-		} catch (DbException |DoesNotExistException|MultipleObjectsReturnedException $e) {
-			throw new ServiceException('Could not find a record for id', $e->getCode(), $e);
+		} catch (DbException | DoesNotExistException | MultipleObjectsReturnedException $e) {
+			throw new ClientException(
+				'Could not find a record for id',
+				$e->getCode(),
+				$e,
+				Http::STATUS_NOT_FOUND
+			);
+		}
+	}
+
+	public function findByToken(string $token): AppointmentConfig {
+		try {
+			return $this->mapper->findByToken($token);
+		} catch (DoesNotExistException $e) {
+			throw new ClientException(
+				"Appointment config $token does not exist",
+				0,
+				$e,
+				Http::STATUS_NOT_FOUND
+			);
 		}
 	}
 
 	/**
 	 * @param int $id
+	 *
 	 * @return AppointmentConfig
 	 * @throws ServiceException
 	 */
 	public function findByIdAndUser(int $id, string $userId): AppointmentConfig {
 		try {
 			return $this->mapper->findByIdForUser($id, $userId);
-		} catch (DbException |DoesNotExistException|MultipleObjectsReturnedException $e) {
+		} catch (DbException | DoesNotExistException | MultipleObjectsReturnedException $e) {
 			throw new ServiceException('Could not find a record for id', $e->getCode(), $e);
 		}
 	}
 
 	/**
 	 * @param AppointmentConfig $appointmentConfig
+	 *
 	 * @return AppointmentConfig
 	 * @throws ServiceException
 	 */
@@ -126,6 +153,7 @@ class AppointmentConfigService {
 	 * @param int $id ?? maybe pass the appointment
 	 * @param int $unixStartTime
 	 * @param int $unixEndTime
+	 *
 	 * @return array
 	 * @throws ServiceException
 	 */
@@ -141,7 +169,7 @@ class AppointmentConfigService {
 		// move this to controller
 		try {
 			$appointment = $this->mapper->findByIdForUser($id);
-		} catch (DbException |DoesNotExistException|MultipleObjectsReturnedException $e) {
+		} catch (DbException | DoesNotExistException | MultipleObjectsReturnedException $e) {
 			throw new ServiceException('Appointment not found', 404, $e);
 		}
 
@@ -194,6 +222,7 @@ class AppointmentConfigService {
 	 * @param int $time
 	 * @param string $outboxUri
 	 * @param array $freeBusyUris
+	 *
 	 * @return [][]
 	 *
 	 * Check if slot is conflicting with existing appointments

lib/Service/Appointments/AvailabilityGenerator.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\Calendar\Service\Appointments;
+
+use OCA\Calendar\Db\AppointmentConfig;
+
+class AvailabilityGenerator {
+
+	/**
+	 * Generate intervals at which the user is generally available
+	 *
+	 * @param AppointmentConfig $config
+	 * @param int $start
+	 * @param int $end
+	 *
+	 * @return Interval[]
+	 */
+	public function generate(AppointmentConfig $config,
+							 int $start,
+							 int $end): array {
+		if ($config->getAvailability() === null) {
+			// No availability -> full time range is available
+			return [
+				new Interval($start, $end),
+			];
+		}
+
+		// TODO: derive intervals from RRULE
+		return [
+			new Interval($start, $end),
+		];
+	}
+
+}

lib/Service/Appointments/Booking.php

@@ -1,183 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-/**
- * Calendar App
- *
- * @copyright 2021 Anna Larch <anna.larch@gmx.net>
- *
- * @author Anna Larch <anna.larch@gmx.net>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
- * License as published by the Free Software Foundation; either
- * version 3 of the License, or any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU AFFERO GENERAL PUBLIC LICENSE for more details.
- *
- * You should have received a copy of the GNU Affero General Public
- * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-namespace OCA\Calendar\Service\Appointments;
-
-use DateTimeImmutable;
-use OCA\Calendar\Db\AppointmentConfig;
-use Recurr\Exception\InvalidRRule;
-use Recurr\Exception\InvalidWeekday;
-use Recurr\Recurrence;
-use Recurr\Rule;
-use Recurr\Transformer\ArrayTransformer;
-use Recurr\Transformer\ArrayTransformerConfig;
-
-class Booking {
-
-	/** @var AppointmentConfig */
-	private $appointmentConfig;
-
-	/** @var int */
-	private $startTime;
-
-	/** @var int */
-	private $endTime;
-
-	/** @var Slot[] */
-	private $slots;
-
-	public function __construct(AppointmentConfig $appointmentConfig, int $startTime, int $endTime, array $slots = []) {
-		$this->appointmentConfig = $appointmentConfig;
-		$this->startTime = $startTime;
-		$this->endTime = $endTime;
-		$this->slots = $slots;
-	}
-	/**
-	 * @return int
-	 */
-	public function getStartTime(): int {
-		return $this->startTime;
-	}
-
-	// Trait maybe?
-	public function getStartTimeDTObj() : DateTimeImmutable {
-		return (new DateTimeImmutable())->setTimestamp($this->startTime);
-	}
-
-	public function getEndTimeDTObj() : DateTimeImmutable {
-		return (new DateTimeImmutable())->setTimestamp($this->endTime);
-	}
-
-	/**
-	 * @param int $startTime
-	 */
-	public function setStartTime(int $startTime): void {
-		$this->startTime = $startTime;
-	}
-
-	/**
-	 * @return int
-	 */
-	public function getEndTime(): int {
-		return $this->endTime;
-	}
-
-	/**
-	 * @param int $endTime
-	 */
-	public function setEndTime(int $endTime): void {
-		$this->endTime = $endTime;
-	}
-
-	/**
-	 * @return Slot[]
-	 */
-	public function getSlots(): array {
-		return $this->slots;
-	}
-
-	/**
-	 * @param Slot[] $slots
-	 */
-	public function setSlots(array $slots): void {
-		$this->slots = $slots;
-	}
-
-	/**
-	 * @return AppointmentConfig
-	 */
-	public function getAppointmentConfig(): AppointmentConfig {
-		return $this->appointmentConfig;
-	}
-
-	/**
-	 * @param AppointmentConfig $appointmentConfig
-	 */
-	public function setAppointmentConfig(AppointmentConfig $appointmentConfig): void {
-		$this->appointmentConfig = $appointmentConfig;
-	}
-
-	public function generateSlots(): array {
-		$slots = [];
-		$unixStartTime = $this->getStartTime();
-		$length = $this->getAppointmentConfig()->getTotalLength()*60;
-		while(($unixStartTime + $length) <= $this->getEndTime() ) {
-			$slots[] = new Slot($unixStartTime, $unixStartTime+$this->getAppointmentConfig()->getTotalLength()*60);
-			$unixStartTime += $this->getAppointmentConfig()->getIncrement()*60;
-		}
-		$this->slots = $slots;
-		return $slots;
-	}
-
-	/**
-	 * @param int $booked
-	 * @return int
-	 */
-	public function getAvailableSlotsAmount(int $booked): int {
-		return ($this->appointmentConfig->getDailyMax() !== null) ? $this->appointmentConfig->getDailyMax() - $booked : 99999;
-	}
-
-	/**
-	 * @return self;
-	 */
-	public function parseRRule(): self {
-		try {
-			// RRule Array Transformer does not work with constraints atm
-			// so this is (kind of) superfluous
-			$startDT = $this->getStartTimeDTObj();
-			$endDT = $this->getEndTimeDTObj();
-			// force UTC
-			$startDT->setTimezone(new \DateTimeZone('UTC'));
-			$endDT->setTimezone(new \DateTimeZone('UTC'));
-			$rule = new Rule($this->appointmentConfig->getAvailability());
-		} catch (InvalidRRule $e) {
-			$this->slots = [];
-			return $this;
-		}
-
-		$config = new ArrayTransformerConfig();
-		$config->enableLastDayOfMonthFix();
-
-		$transformer = new ArrayTransformer();
-		$transformer->setConfig($config);
-
-		try {
-			$collection = $transformer->transform($rule);
-		} catch (InvalidWeekday $e) {
-			// throw an error here?
-			$this->slots = [];
-			return $this;
-		}
-
-		$this->slots = $collection->map(function (Recurrence $slot) {
-			$start = $slot->getStart()->getTimestamp();
-			$end = $start + ($this->appointmentConfig->getTotalLength() * 60);
-			return new Slot($start, $end);
-		})->toArray();
-
-		return $this;
-	}
-}

lib/Service/Appointments/BookingService.php

@@ -22,24 +22,36 @@ declare(strict_types=1);
  * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
+
 namespace OCA\Calendar\Service\Appointments;
 
 use OC\Calendar\CalendarQuery;
+use OCA\Calendar\Db\AppointmentConfig;
 use OCA\Calendar\Db\AppointmentConfigMapper;
 use OCP\Calendar\IManager;
 
 class BookingService {
 
-	/** @var IManager */
-	private $manager;
+	/** @var AvailabilityGenerator */
+	private $availabilityGenerator;
 
-	/** @var AppointmentConfigMapper */
-	private $mapper;
+	/** @var SlotExtrapolator */
+	private $extrapolator;
 
-	public function __construct(IManager $manager,
-	AppointmentConfigMapper $mapper) {
-		$this->manager = $manager;
-		$this->mapper = $mapper;
+	/** @var DailyLimitFilter */
+	private $dailyLimitFilter;
+
+	/** @var EventConflictFilter */
+	private $eventConflictFilter;
+
+	public function __construct(AvailabilityGenerator $availabilityGenerator,
+								SlotExtrapolator $extrapolator,
+								DailyLimitFilter $dailyLimitFilter,
+								EventConflictFilter $eventConflictFilter) {
+		$this->availabilityGenerator = $availabilityGenerator;
+		$this->extrapolator = $extrapolator;
+		$this->dailyLimitFilter = $dailyLimitFilter;
+		$this->eventConflictFilter = $eventConflictFilter;
 	}
 
 	// CREATE
@@ -47,74 +59,20 @@ class BookingService {
 		// use new ICreateFromString::create method
 	}
 
-	public function getBookingInformation(string $token) {
-		// unmarshal token for ID would be an option too
-		// this also returns all bookings for this token
-		// needs a unique identifier - X-NC-USERID or something?
-		$config = $this->mapper->findByToken($token);
-		$query = $this->manager->newQuery($config->getPrincipalUri());
-		$query->addSearchCalendar($config->getTargetCalendarUri());
-		return $this->manager->searchForPrincipal($query);
-	}
-
-	public function getSlots(Booking $booking): array {
-		$bookedSlots = $this->findBookedSlotsAmount($booking);
-
-		// negotiate available slots
-		if ($booking->getAvailableSlotsAmount($bookedSlots) <= 0) {
-			return [];
-		}
-
-		// decide if we want to use the complete 24 hour period to intersect via:
-		// $booking->generateSlots();
-		// Remove unavailable slots via comparing with RRule
-		$booking->parseRRule();
-
-		// remove conflicting slots via calendar free busy
-		$booking = $this->getCalendarFreeTimeblocks($booking);
-		return $booking->getSlots();
-	}
-
 	/**
-	 * @param Booking $booking
-	 * @return Booking
-	 *
-	 * Check if slot is conflicting with existing appointments
+	 * @return Interval[]
 	 */
-	public function getCalendarFreeTimeblocks(Booking $booking): Booking {
-		$query = $this->manager->newQuery($booking->getAppointmentConfig()->getPrincipalUri());
-		$query->addSearchCalendar($booking->getAppointmentConfig()->getTargetCalendarUri());
+	public function getAvailableSlots(AppointmentConfig $config, int $startTime, int $endTime): array {
+		// 1. Build intervals at which slots may be booked
+		$availabilityIntervals = $this->availabilityGenerator->generate($config, $startTime, $endTime);
+		// 2. Generate all possible slots
+		$allPossibleSlots = $this->extrapolator->extrapolate($config, $availabilityIntervals);
+		// 3. Filter out the daily limits
+		$filteredByDailyLimit = $this->dailyLimitFilter->filter($config, $allPossibleSlots);
+		// 4. Filter out booking conflicts
+		$filteredByConflict = $this->eventConflictFilter->filter($config, $filteredByDailyLimit);
 
-		if (!empty($booking->getAppointmentConfig()->getCalendarFreebusyUris())) {
-			foreach ($booking->getAppointmentConfig()->getCalendarFreebusyUris() as $uri) {
-				$query->addSearchCalendar($uri);
-			}
-		}
-
-		$slots = $booking->getSlots();
-		foreach ($slots as $k => $slot) {
-			$query->setTimerangeStart($slot->getStartTimeDTObj());
-			$query->setTimerangeEnd($slot->getEndTimeDTObj());
-			// cache the query maybe? or maybe run everything at once?
-			$events = $this->manager->searchForPrincipal($query);
-			if (!empty($events)) {
-				unset($slots[$k]);
-			}
-		}
-		$booking->setSlots($slots);
-		return $booking;
-	}
-
-	public function findBookedSlotsAmount(Booking $booking): int {
-		/** @var CalendarQuery $query */
-		$query = $this->manager->newQuery($booking->getAppointmentConfig()->getPrincipalUri());
-		$query->addSearchCalendar($booking->getAppointmentConfig()->getTargetCalendarUri());
-		$query->addSearchProperty('X-NC-APPOINTMENT');
-		$query->setSearchPattern($booking->getAppointmentConfig()->getToken());
-		$query->setTimerangeStart($booking->getStartTimeDTObj());
-		$query->setTimerangeEnd($booking->getEndTimeDTObj());
-		$events = $this->manager->searchForPrincipal($query);
-		return count($events);
+		return $filteredByConflict;
 	}
 
 	// Update

lib/Service/Appointments/DailyLimitFilter.php

@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\Calendar\Service\Appointments;
+
+use OC\Calendar\CalendarQuery;
+use OCA\Calendar\Db\AppointmentConfig;
+use OCP\Calendar\IManager;
+use function array_filter;
+use function array_values;
+use function count;
+
+class DailyLimitFilter {
+
+	/** @var IManager */
+	private $calendarManger;
+
+	public function __construct(IManager $calendarManger) {
+		$this->calendarManger = $calendarManger;
+	}
+
+	/**
+	 * @param AppointmentConfig $config
+	 * @param Interval[] $slots
+	 *
+	 * @return Interval[]
+	 */
+	public function filter(AppointmentConfig $config, array $slots): array {
+		// 0. If there is no limit then we don't have to filter anything
+		if ($config->getDailyMax() === 0) {
+			return $slots;
+		}
+
+		// 1. Find all days
+		$days = [];
+		foreach ($slots as $slot) {
+			$startOfDay = $slot->getStartAsObject()->setTime(0, 0, 0, 0);
+			$ts = $startOfDay->getTimestamp();
+			$days[$ts] = $startOfDay;
+		}
+
+		// 2. Check what days are bookable
+		/** @var CalendarQuery $query */
+		$query = $this->calendarManger->newQuery($config->getPrincipalUri());
+		$query->addSearchCalendar($config->getTargetCalendarUri());
+		$query->addSearchProperty('X-NC-APPOINTMENT');
+		$query->setSearchPattern($config->getToken());
+		$available = [];
+		foreach ($days as $ts => $day) {
+			$nextDay = $day->modify('+1 day');
+			$query->setTimerangeStart($day);
+			$query->setTimerangeEnd($nextDay);
+
+			$events = $this->calendarManger->searchForPrincipal($query);
+
+			// Only days with less than the max number are still available
+			$available[$ts] = count($events) < $config->getDailyMax();
+		}
+
+		// 3. Filter out the slots that are on an unavailable day
+		return array_values(array_filter($slots, function(Interval $slot) use ($available): bool {
+			$startOfDay = $slot->getStartAsObject()->setTime(0, 0, 0, 0);
+			$ts = $startOfDay->getTimestamp();
+			return $available[$ts];
+		}));
+	}
+}

lib/Service/Appointments/EventConflictFilter.php

@@ -0,0 +1,72 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\Calendar\Service\Appointments;
+
+use DateInterval;
+use OCA\Calendar\Db\AppointmentConfig;
+use OCP\Calendar\IManager;
+use function array_filter;
+
+class EventConflictFilter {
+
+	/** @var IManager */
+	private $calendarManager;
+
+	public function __construct(IManager $calendarManager) {
+		$this->calendarManager = $calendarManager;
+	}
+
+	/**
+	 * Filter appointment slots to those that do not conflict with existing calendar events
+	 *
+	 * @todo try to combine slots a bit to lower the number of calendar queries
+	 *
+	 * @param AppointmentConfig $config
+	 * @param Interval[] $slots
+	 *
+	 * @return Interval[]
+	 */
+	public function filter(AppointmentConfig $config, array $slots): array {
+		$query = $this->calendarManager->newQuery($config->getPrincipalUri());
+		foreach ($config->getCalendarFreebusyUrisAsArray() as $uri) {
+			$query->addSearchCalendar($uri);
+		}
+		// Always check the target calendar for conflicts
+		$query->addSearchCalendar($config->getTargetCalendarUri());
+		$preparationDuration = DateInterval::createFromDateString($config->getPreparationDuration() . ' minutes');
+		$followUpDuration = DateInterval::createFromDateString($config->getFollowupDuration() . ' minutes');
+
+		return array_filter($slots, function(Interval $slot) use ($followUpDuration, $preparationDuration, $query): bool {
+			$query->setTimerangeStart($slot->getStartAsObject()->sub($preparationDuration));
+			$query->setTimerangeEnd($slot->getEndAsObject()->add($followUpDuration));
+
+			$objects = $this->calendarManager->searchForPrincipal($query);
+
+			// If there is at least one event at this time then the slot is taken
+			return empty($objects);
+		});
+	}
+}

lib/Service/Appointments/Interval.php

@@ -1,6 +1,7 @@
 <?php
 
 declare(strict_types=1);
+
 /**
  * Calendar App
  *
@@ -22,12 +23,21 @@ declare(strict_types=1);
  * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
+
 namespace OCA\Calendar\Service\Appointments;
 
 use DateTimeImmutable;
+use JsonSerializable;
 
-class Slot {
+/**
+ * @psalm-immutable
+ */
+class Interval implements JsonSerializable {
+
+	/** @var int */
 	private $start;
+
+	/** @var int */
 	private $end;
 
 	public function __construct(int $start, int $end) {
@@ -35,31 +45,26 @@ class Slot {
 		$this->end = $end;
 	}
 
-	public function getStartTime(): int {
+	public function getStart(): int {
 		return $this->start;
 	}
 
-	public function setStartTime(int $start): void {
-		$this->start = $start;
-	}
-
-	public function getEndTime(): int {
+	public function getEnd(): int {
 		return $this->end;
 	}
 
-	public function setEndTime(int $end): void {
-		$this->end = $end;
-	}
-
-	public function getStartTimeDTObj() : DateTimeImmutable {
+	public function getStartAsObject(): DateTimeImmutable {
 		return (new DateTimeImmutable())->setTimestamp($this->start);
 	}
 
-	public function getEndTimeDTObj() : DateTimeImmutable {
+	public function getEndAsObject(): DateTimeImmutable {
 		return (new DateTimeImmutable())->setTimestamp($this->end);
 	}
 
-	public function isViable(int $start, int $end): bool {
-		return !($this->start > $start || $this->end < $end);
+	public function jsonSerialize(): array {
+		return [
+			'start' => $this->start,
+			'end' => $this->end,
+		];
 	}
 }

lib/Service/Appointments/SlotExtrapolator.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\Calendar\Service\Appointments;
+
+use OCA\Calendar\Db\AppointmentConfig;
+
+class SlotExtrapolator {
+
+	/**
+	 * @param AppointmentConfig $config
+	 * @param Interval[] $availabilityIntervals
+	 * @param int $to
+	 *
+	 * @return Interval[]
+	 */
+	public function extrapolate(AppointmentConfig $config,
+								array $availabilityIntervals): array {
+		$increment = $config->getIncrement() * 60;
+		$length = $config->getLength() * 60;
+		$slots = [];
+
+		foreach ($availabilityIntervals as $available) {
+			$from = $available->getStart();
+			$to = $available->getEnd();
+
+			for ($t = $from; ($t + $length) <= $to; $t += $increment) {
+				$slots[] = new Interval($t, $t + $length);
+			}
+		}
+
+		return $slots;
+	}
+}

src/appointments/main-booking.js

@@ -0,0 +1,53 @@
+/**
+ * @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ * @author 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import { getRequestToken } from '@nextcloud/auth'
+import { loadState } from '@nextcloud/initial-state'
+import { linkTo } from '@nextcloud/router'
+import { translate, translatePlural } from '@nextcloud/l10n'
+import Vue from 'vue'
+
+import Booking from '../views/Appointments/Booking'
+
+// CSP config for webpack dynamic chunk loading
+// eslint-disable-next-line
+__webpack_nonce__ = btoa(getRequestToken())
+
+// Correct the root of the app for chunk loading
+// OC.linkTo matches the apps folders
+// OC.generateUrl ensure the index.php (or not)
+// We do not want the index.php since we're loading files
+// eslint-disable-next-line
+__webpack_public_path__ = linkTo('calendar', 'js/')
+
+Vue.prototype.$t = translate
+Vue.prototype.$n = translatePlural
+
+const config = loadState('calendar', 'config')
+const userInfo = loadState('calendar', 'userInfo')
+
+export default new Vue({
+	el: '#appointment-booking',
+	render: h => h(Booking, {
+		props: {
+			config,
+			userInfo,
+		},
+	}),
+})

src/components/AppNavigation/Settings/ShortcutOverview.vue

@@ -52,7 +52,7 @@
 							v-if="index2 !== (shortcut.keys.length - 1)"
 							:key="`${category.categoryId}-${index}-${index2}`"
 							class="shortcut-section-item__spacer">
-							{{ t('calendar', 'or') }}
+							{{ $t('calendar', 'or') }}
 						</span>
 					</template>
 				</span>

src/components/Appointments/AppointmentDetails.vue

@@ -0,0 +1,166 @@
+<template>
+	<Modal
+		size="large"
+		@close="$emit('close')">
+		<div class="booking-appointment-details">
+			<div class="booking-details">
+				<Avatar
+					:user="userInfo.uid"
+					:display-name="userInfo.displayName"
+					:disable-tooltip="true"
+					:disable-menu="true"
+					:size="64" />
+				<div class="booking__display-name">
+					<strong>{{ userInfo.displayName }}</strong>
+				</div>
+				<h2 class="booking__name">
+					{{ config.name }}
+				</h2>
+				<span class="booking__description">{{ config.description }}</span>
+				<span class="booking__time">{{ startTime }} - {{ endTime }}</span>
+			</div>
+			<div class="appointment-details">
+				<h2>{{ $t('calendar', 'Enter details') }}</h2>
+				<div>
+					{{ $t('calendar', 'Name') }}
+				</div>
+				<input id="name"
+					v-model="name"
+					type="text"
+					class="no-close"
+					required>
+				<div>
+					{{ $t('calendar', 'Email') }}
+				</div>
+				<input ref="email"
+					v-model="email"
+					type="email"
+					autocapitalize="none"
+					autocomplete="on"
+					autocorrect="off"
+					required>
+				<div class="meeting-info">
+					{{ $t('calendar', 'Please share anything that will help prepare for our meeting') }}
+					<div class="meeting-text">
+						<textarea
+							id="biography"
+							v-model="description"
+							rows="8"
+							autocapitalize="none"
+							autocomplete="off" />
+					</div>
+				</div>
+				<button class="button primary"
+					@click="save">
+					{{ $t('calendar', 'Book the appointment') }}
+				</button>
+			</div>
+		</div>
+	</Modal>
+</template>
+<script>
+import Avatar from '@nextcloud/vue/dist/Components/Avatar'
+import Modal from '@nextcloud/vue/dist/Components/Modal'
+
+import { timeStampToLocaleTime } from '../../utils/localeTime'
+
+export default {
+	name: 'AppointmentDetails',
+	components: {
+		Avatar,
+		Modal,
+	},
+	props: {
+		config: {
+			required: true,
+			type: Object,
+		},
+		timeSlot: {
+			required: true,
+			type: Object,
+		},
+		userInfo: {
+			required: true,
+			type: Object,
+		},
+	},
+	data() {
+		return {
+			description: '',
+			email: '',
+			name: '',
+		}
+	},
+	computed: {
+		startTime() {
+			return timeStampToLocaleTime(this.timeSlot.start, this.timeZoneId)
+		},
+		endTime() {
+			return timeStampToLocaleTime(this.timeSlot.end, this.timeZoneId)
+		},
+	},
+	methods: {
+		save() {
+			this.$emit('save', {
+				slot: this.timeSlot,
+				description: this.description,
+				email: this.email,
+				name: this.name,
+			})
+		},
+	},
+}
+</script>
+
+<style lang="scss" scoped>
+::v-deep .modal-container {
+  width: calc(100vw - 120px) !important;
+  height: calc(100vh - 120px) !important;
+  max-width: 600px !important;
+  max-height: 500px !important;
+}
+.booking-appointment-details {
+	display: flex;
+	flex-direction: row;
+}
+.booking-details {
+	padding-left: 30px;
+	padding-top: 80px;
+	white-space: nowrap;
+}
+
+.appointment-details {
+	padding-left: 120px;
+	padding-top: 40px;
+}
+.add-guest {
+	display: block;
+	color: var(--color-primary);
+	background-color: transparent;
+}
+.meeting-info {
+padding-right: 10px;
+}
+.meeting-text {
+	display: grid;
+	align-items: center;
+
+	textarea {
+	  resize: vertical;
+	  grid-area: 1 / 1;
+	  width: 100%;
+	  margin: 3px 3px 3px 0;
+	  padding: 7px 6px;
+	  color: var(--color-main-text);
+	  border: 1px solid var(--color-border-dark);
+	  border-radius: var(--border-radius);
+	  background-color: var(--color-main-background);
+	  cursor: text;
+
+	  &:hover {
+		border-color: var(--color-primary-element) !important;
+		outline: none !important;
+	  }
+	}
+}
+</style>

src/components/Appointments/AppointmentSlot.vue

@@ -0,0 +1,63 @@
+<!--
+  - @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+  -
+  - @author 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
+  -
+  - @license GNU AGPL version 3 or any later version
+  -
+  - This program is free software: you can redistribute it and/or modify
+  - it under the terms of the GNU Affero General Public License as
+  - published by the Free Software Foundation, either version 3 of the
+  - License, or (at your option) any later version.
+  -
+  - This program is distributed in the hope that it will be useful,
+  - but WITHOUT ANY WARRANTY; without even the implied warranty of
+  - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  - GNU Affero General Public License for more details.
+  -
+  - You should have received a copy of the GNU Affero General Public License
+  - along with this program.  If not, see <http://www.gnu.org/licenses/>.
+  -->
+
+<template>
+	<button class="appointment-slot" @click="$emit('click', $event)">
+		{{ startTime }} - {{ endTime }}
+	</button>
+</template>
+
+<script>
+import { timeStampToLocaleTime } from '../../utils/localeTime'
+
+export default {
+	name: 'AppointmentSlot',
+	props: {
+		start: {
+			required: true,
+			type: Number,
+		},
+		end: {
+			required: true,
+			type: Number,
+		},
+		timeZoneId: {
+			required: true,
+			type: String,
+		},
+	},
+	computed: {
+		dateTimeFormatter() {
+			return Intl.DateTimeFormat(undefined, {
+				timeZone: this.timeZoneId,
+				timeStyle: 'full',
+				dateStyle: 'short',
+			})
+		},
+		startTime() {
+			return timeStampToLocaleTime(this.start, this.timeZoneId)
+		},
+		endTime() {
+			return timeStampToLocaleTime(this.end, this.timeZoneId)
+		},
+	},
+}
+</script>