feat(billing): renewals, coupons, VAT numbering, billing cycles and invoice payment tracking

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

app/Repositories/Concerns/FiltersBillingRecords.php

@@ -2,6 +2,7 @@
 
 namespace App\Repositories\Concerns;
 
+use App\Models\InvoiceAttachment;
 use Carbon\Carbon;
 use Illuminate\Database\Eloquent\Builder;
 
@@ -28,6 +29,53 @@ trait FiltersBillingRecords
             ->when($to, fn (Builder $q) => $q->where('created_at', '<=', Carbon::parse($to)->endOfDay()));
     }
 
+    /** @param callable(): array<int, mixed> $duplicates */
+    private function whereIsDuplicate(Builder $query, mixed $flag, callable $duplicates): Builder
+    {
+        if (!filter_var($flag, FILTER_VALIDATE_BOOLEAN)) {
+            return $query;
+        }
+
+        return $query->whereIn($query->getModel()->getQualifiedKeyName(), array_keys($duplicates()));
+    }
+
+    /**
+     * @param array<int, string> $columns
+     */
+    private function applySort(Builder $query, mixed $sortBy, mixed $sortOrder, array $columns): Builder
+    {
+        $direction = strtolower((string) $sortOrder) === 'asc' ? 'asc' : 'desc';
+        $table = $query->getModel()->getTable();
+
+        if ($sortBy === 'customer') {
+            return $query
+                ->orderBy(
+                    \App\Models\Customer::query()->select('fullname')->whereColumn('customers.id', "{$table}.customer_id")->limit(1),
+                    $direction
+                )
+                ->orderByDesc("{$table}.id");
+        }
+
+        if ($sortBy === 'outstanding' && in_array($sortBy, $columns, true)) {
+            return $query
+                ->orderByRaw("GREATEST({$table}.total - COALESCE({$table}.amount_paid, 0), 0) {$direction}")
+                ->orderByDesc("{$table}.id");
+        }
+
+        if (!in_array($sortBy, $columns, true)) {
+            return $query;
+        }
+
+        return $query->orderBy("{$table}.{$sortBy}", $direction)->orderByDesc("{$table}.id");
+    }
+
+    private function whereContractFileLike(Builder $query, string $attachmentsRelation, string $search): Builder
+    {
+        return $query->orWhereHas($attachmentsRelation, fn (Builder $files) => $files
+            ->where('type', InvoiceAttachment::TYPE_CONTRACT)
+            ->where('filename', 'like', "%{$search}%"));
+    }
+
     private function whereOrderItemNameLike(Builder $query, string $orderItemsRelation, string $search): Builder
     {
         return $query->orWhereHas($orderItemsRelation, fn (Builder $items) => $items