feat(inventory): add traceable cart stock reservations

app/Domains/Catalog/Models/Inventory.php

@@ -5,6 +5,7 @@ namespace App\Domains\Catalog\Models;
 use Illuminate\Database\Eloquent\Attributes\Fillable;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\HasOne;
 
 #[Fillable([
@@ -47,6 +48,12 @@ class Inventory extends Model
         return $this->hasOne(Variant::class);
     }
 
+    /** @return HasMany<StockReservation, $this> */
+    public function stockReservations(): HasMany
+    {
+        return $this->hasMany(StockReservation::class);
+    }
+
     public function availableStock(): int
     {
         return max(0, $this->real_stock - $this->reserved_stock);

app/Domains/Catalog/Models/StockReservation.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace App\Domains\Catalog\Models;
+
+use App\Domains\Cart\Models\CartItem;
+use App\Domains\Purchase\Models\Purchase;
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+#[Fillable([
+    'inventory_id',
+    'cart_item_id',
+    'purchase_id',
+    'quantity',
+    'status',
+    'expires_at',
+    'committed_at',
+    'released_at',
+])]
+class StockReservation extends Model
+{
+    public const STATUS_ACTIVE = 'active';
+
+    public const STATUS_COMMITTED = 'committed';
+
+    public const STATUS_RELEASED = 'released';
+
+    public const STATUS_EXPIRED = 'expired';
+
+    protected function casts(): array
+    {
+        return [
+            'inventory_id' => 'integer',
+            'cart_item_id' => 'integer',
+            'purchase_id' => 'integer',
+            'quantity' => 'integer',
+            'expires_at' => 'datetime',
+            'committed_at' => 'datetime',
+            'released_at' => 'datetime',
+        ];
+    }
+
+    /** @return BelongsTo<Inventory, $this> */
+    public function inventory(): BelongsTo
+    {
+        return $this->belongsTo(Inventory::class);
+    }
+
+    /** @return BelongsTo<CartItem, $this> */
+    public function cartItem(): BelongsTo
+    {
+        return $this->belongsTo(CartItem::class);
+    }
+
+    /** @return BelongsTo<Purchase, $this> */
+    public function purchase(): BelongsTo
+    {
+        return $this->belongsTo(Purchase::class);
+    }
+}