Exercise 01: recording a temperature at a location in the event store

exercises/exercise-01/record-temperature.php

@@ -9,22 +9,21 @@
 use BadMethodCallException;
 use EventSourcingWorkshop\EventSourcing\Domain\DomainEvent;
 use EventSourcingWorkshop\Glue\Application\Kernel;
+use EventSourcingWorkshop\TemperatureTracking\Domain\TemperatureRecorded;
 use Psl\Env;
 use Psl\Type;
 use Throwable;
 use UnexpectedValueException;
 
 /**
  * Usage: ./record-temperature.php <string $location> <float $celsius>
- *
- * @psalm-suppress UnusedVariable until the exercise is complete, some unused symbols may be sitting around
  */
 (static function (): void {
     require_once __DIR__ . '/../../vendor/autoload.php';
 
     try {
         [, $location, $temperature] = Type\shape([
-            1 => Type\string(),
+            1 => Type\non_empty_string(),
             2 => Type\float(),
         ])->coerce(Env\args());
     } catch (Throwable $e) {
@@ -38,12 +37,14 @@
     /**
      * Here we want to:
      *
-     * @TODO 1. create a new `TemperatureRecorded` {@see DomainEvent} implementation under ../src/TemperatureTracking/Domain
-     * @TODO 2. raise the event
-     * @TODO 2. save that event to the event store (tip: check the `$kernel`'s {@see Kernel::$traverseEventStream})
-     * @TODO 3. observe the event store
+     * 1. create a new `TemperatureRecorded` {@see DomainEvent} implementation under ../src/TemperatureTracking/Domain
+     * 2. raise the event
+     * 2. save that event to the event store (tip: check the `$kernel`'s {@see Kernel::$eventStore})
+     * 3. observe the event store
      *
      * Question: what was saved in the DB?
      */
-    throw new BadMethodCallException('Incomplete: remove me once finished with the exercise!');
+    $kernel->eventStore->save(
+        new TemperatureRecorded($location, $temperature, $kernel->clock->now()),
+    );
 })();

src/TemperatureTracking/Domain/TemperatureRecorded.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace EventSourcingWorkshop\TemperatureTracking\Domain;
+
+use DateTimeImmutable;
+use EventSourcingWorkshop\EventSourcing\Domain\DomainEvent;
+
+/** @psalm-immutable */
+final class TemperatureRecorded implements DomainEvent
+{
+    /** @param non-empty-string $location */
+    public function __construct(
+        public readonly string $location,
+        public readonly float $celsius,
+        public readonly DateTimeImmutable $raisedAt,
+    ) {
+    }
+
+    public function raisedAt(): DateTimeImmutable
+    {
+        return $this->raisedAt;
+    }
+
+    /** {@inheritDoc} */
+    public function toArray(): array
+    {
+        return [
+            'location' => $this->location,
+            'celsius'  => $this->celsius,
+            'raisedAt' => $this->raisedAt->format(DateTimeImmutable::RFC3339_EXTENDED),
+        ];
+    }
+}