feat(Assignments): Implement recurrence rule checking

Signed-off-by: Marcel Klehr <mklehr@gmx.net>

Author: marcelklehr

composer.json

@@ -17,6 +17,7 @@
 		"html2text/html2text": "^4.3",
 		"phpoffice/phpword": "^1.2",
 		"ralouphie/mimey": "^1.0",
+		"simshaun/recurr": "^5.0",
 		"smalot/pdfparser": "^2.11"
 	},
 	"scripts": {

composer.lock

@@ -132,6 +132,7 @@ public function getUserAssignment(int $id): DataResponse {
 	 *
 	 * 200: User tasks returned
 	 * 403: User not logged in
+	 * 400: Malformed recurrence rule
 	 */
 	#[NoAdminRequired]
 	#[OpenAPI(scope: OpenAPI::SCOPE_DEFAULT, tags: ['assignments'])]
@@ -144,7 +145,11 @@ public function updateUserAssignment(int $id, ?string $prompt, ?string $recurren
 					$assignment->setPrompt($prompt);
 				}
 				if ($recurrence !== null) {
-					$assignment->setRecurrence($recurrence);
+					try {
+						$assignment->setRecurrence($recurrence);
+					} catch (\InvalidArgumentException $e) {
+						return new DataResponse('', HTTP::STATUS_BAD_REQUEST);
+					}
 				}
 				if ($startsAt !== null) {
 					$assignment->setStartsAt($startsAt);

lib/Controller/AssignmentsApiController.php

@@ -11,14 +11,20 @@
 
 use OCP\AppFramework\Db\Entity;
 use OCP\DB\Types;
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Container\NotFoundExceptionInterface;
+use Recurr\Exception\InvalidRRule;
+use Recurr\RecurrenceCollection;
+use Recurr\Rule;
+use Recurr\Transformer\Constraint\AfterConstraint;
+use function OCP\Log\logger;
 
 /**
  * @method \string getUserId()
  * @method \void setUserId(string $userId)
  * @method \string getPrompt()
  * @method \void setPrompt(string $prompt)
  * @method \string getRecurrence()
- * @method \void setRecurrence(string $recurrence)
  * @method \int getStartsAt()
  * @method \void setStartsAt(int $startsAt)
  * @method \int getCreatedAt()
@@ -89,11 +95,41 @@ public function jsonSerialize() {
 		];
 	}
 
+	/**
+	 * @throws \InvalidArgumentException
+	 */
+	public function setRecurrence(string $recurrence): void {
+		try {
+			new Rule($recurrence);
+		} catch (InvalidRRule $e) {
+			throw new \InvalidArgumentException('Invalid recurrence rule: ' . $recurrence, previous: $e);
+		}
+		$this->setter('recurrence', [$recurrence]);
+	}
+
 	/**
 	 * Evaluates the recurrence rule and checks if a run is due
 	 */
 	public function isDueToRun(\DateTimeImmutable $now): bool {
-		// TODO: Use an actual algorithm here
-		return true;
+		try {
+			$startsAt = new \DateTime('@' . $this->getStartsAt());
+			// Find recurrences after the last run or after the current time if this assignment has never run
+			$rule = new Rule($this->getRecurrence(), $startsAt);
+			$transformer = new \Recurr\Transformer\ArrayTransformer();
+			$constraint = new AfterConstraint($this->getLastRunAt() !== 0 ? new \DateTime('@' . $this->getLastRunAt()) : $startsAt, true);
+			/** @var RecurrenceCollection $collection */
+			$collection = $transformer->transform($rule, $constraint);
+			if ($collection->isEmpty()) {
+				return false;
+			}
+			$nextRecurrence = $collection->first();
+			if ($nextRecurrence->getStart()->getTimestamp() <= $now->getTimestamp() && $nextRecurrence->getStart()->getTimestamp() > $this->getLastRunAt()) {
+				return true;
+			}
+		} catch (InvalidRRule|\Exception|NotFoundExceptionInterface|ContainerExceptionInterface $e) {
+			// this should not happen, as we validate the rule on setRecurrence, but just in case, we catch the exception and log it
+			logger('assistant')->error($e->getMessage(), ['exception' => $e]);
+		}
+		return false;
 	}
 }