Перевод на доменную архитектуру

app/Domain/Reports/Calculators/PreoperativeDaysCalculator.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Domain\Reports\Calculators;
+
+use App\Domain\Reports\Models\MetricAggregate;
+use App\Domain\Reports\Models\OperationInterval;
+
+final class PreoperativeDaysCalculator
+{
+    /**
+     * @param  iterable<OperationInterval>  $intervals
+     */
+    public function calculate(iterable $intervals): MetricAggregate
+    {
+        $totalDays = 0;
+        $patientCount = 0;
+
+        foreach ($intervals as $interval) {
+            if ($interval->operationAt < $interval->admittedAt) {
+                continue;
+            }
+
+            $totalDays += $interval->admittedAt->setTime(0, 0)->diff($interval->operationAt->setTime(0, 0))->days;
+            $patientCount++;
+        }
+
+        return new MetricAggregate(
+            total: $totalDays,
+            count: $patientCount,
+            average: $patientCount > 0 ? round($totalDays / $patientCount, 1) : 0.0,
+        );
+    }
+}