optimizations

app/Services/CollectionCanonicalService.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Services;
+
+use App\Models\Collection;
+use App\Models\CollectionMergeAction;
+use App\Models\User;
+use Illuminate\Validation\ValidationException;
+
+class CollectionCanonicalService
+{
+    public function designate(Collection $source, Collection $target, ?User $actor = null): Collection
+    {
+        if ((int) $source->id === (int) $target->id) {
+            throw ValidationException::withMessages([
+                'target_collection_id' => 'A collection cannot canonicalize to itself.',
+            ]);
+        }
+
+        $source->forceFill([
+            'canonical_collection_id' => $target->id,
+            'health_state' => Collection::HEALTH_MERGE_CANDIDATE,
+            'placement_eligibility' => false,
+        ])->save();
+
+        CollectionMergeAction::query()->create([
+            'source_collection_id' => $source->id,
+            'target_collection_id' => $target->id,
+            'action_type' => 'approved',
+            'actor_user_id' => $actor?->id,
+            'summary' => 'Canonical target designated.',
+        ]);
+
+        app(CollectionHistoryService::class)->record(
+            $source->fresh(),
+            $actor,
+            'canonicalized',
+            'Collection canonical target designated.',
+            null,
+            ['canonical_collection_id' => (int) $target->id]
+        );
+
+        return $source->fresh();
+    }
+}