取消订单时,退还赠送的赠品

app/Models/ProductGift.php

@@ -25,4 +25,14 @@ class ProductGift extends Model
     {
         return $this->belongsTo(ProductSku::class, 'gift_sku_id');
     }
+
+    /**
+     * 确认此赠品是否有限制
+     *
+     * @return bool
+     */
+    public function isLimit(): bool
+    {
+        return $this->limit !== 0;
+    }
 }

app/Services/OrderService.php

@@ -12,6 +12,7 @@ use App\Helpers\Numeric;
 use App\Helpers\Order as OrderHelper;
 use App\Models\Order;
 use App\Models\OrderProduct;
+use App\Models\ProductGift;
 use App\Models\ProductSku;
 use App\Models\ShippingAddress;
 use App\Models\User;
@@ -293,28 +294,29 @@ class OrderService
                 continue;
             }
 
+            // 需赠送礼品的总数
+            $num = $gift->num * $qty;
+
             // 如果赠品有限，且剩余数量不足时，直接赠送剩余赠品
-            if ($gift->limit !== 0 && $gift->remaining < $qty) {
+            if ($gift->isLimit() && $num > $gift->remaining) {
-                $qty = $gift->remaining;
+                // 计算剩余可赠送的份数
+                $remainingQty = (int) ($gift->remaining / $gift->num);
+
+                $num = $gift->num * $remainingQty;
             }
 
-            // 如果赠送的份数小于1，则不赠送
+            if ($gift->isLimit()) {
-            if ($qty < 1) {
-                continue;
-            }
-
-            if ($gift->limit === 0) {
-                $gift->increment('sent', $qty);
-            } else {
                 $gift->update([
-                    'remaining' => DB::raw("remaining-{$qty}"),
+                    'remaining' => DB::raw("remaining-{$num}"),
-                    'sent' => DB::raw("sent+{$qty}"),
+                    'sent' => DB::raw("sent+{$num}"),
                 ]);
+            } else {
+                $gift->increment('sent', $num);
             }
 
             $gifts[] = [
                 'sku' => $gift->giftSku,
-                'num' => $qty*$gift->num, // 赠送商品总数
+                'num' => $num, // 赠送商品总数
             ];
         }
 
@@ -790,9 +792,31 @@ class OrderService
         $products = $order->products()->get();
 
         foreach ($products->load('sku') as $product) {
-            // 取消订单时，赠品不退回
+            if ($product->sku === null) {
+                continue;
+            }
+
+            // 如果商品不是赠品，则直接增加商品库存
             if (! $product->isGift()) {
-                $product->sku?->increment('stock', $product->quantity);
+                $product->sku->increment('stock', $product->quantity);
+                continue;
+            }
+
+            $gift = ProductGift::where('sku_id', $product->gift_for_sku_id)
+                            ->where('gift_sku_id', $product->sku_id)
+                            ->first();
+
+            if ($gift === null) {
+                continue;
+            }
+
+            if ($gift->isLimit()) {
+                $gift->update([
+                    'remaining' => DB::raw("remaining+{$product->quantity}"),
+                    'sent' => DB::raw("sent-{$product->quantity}"),
+                ]);
+            } else {
+                $gift->decrement('sent', $product->quantity);
             }
         }
 

database/migrations/2021_12_06_135928_create_product_gifts_table.php

@@ -18,8 +18,8 @@ class CreateProductGiftsTable extends Migration
             $table->unsignedBigInteger('sku_id')->comment('主SKU商品ID');
             $table->unsignedBigInteger('gift_sku_id')->comment('赠品SKU商品ID');
             $table->unsignedInteger('num')->default(0)->comment('每份赠送数量');
-            $table->unsignedInteger('limit')->default(0)->comment('上限（份）');
+            $table->unsignedInteger('limit')->default(0)->comment('上限个数');
-            $table->unsignedInteger('sent')->default(0)->comment('已送（份）');
+            $table->unsignedInteger('sent')->default(0)->comment('已送个数');
             $table->timestamps();
         });
     }

database/migrations/2021_12_20_202109_add_remaining_to_product_gifts_table.php

@@ -14,7 +14,7 @@ class AddRemainingToProductGiftsTable extends Migration
     public function up()
     {
         Schema::table('product_gifts', function (Blueprint $table) {
-            $table->unsignedInteger('remaining')->default(0)->comment('剩余（份）');
+            $table->unsignedInteger('remaining')->default(0)->comment('剩余个数');
         });
     }