调整后台减免金额

app/Admin/Services/OrderService.php

@@ -7,6 +7,7 @@ use App\Events\OrderPaid;
 use App\Exceptions\BizException;
 use App\Models\Order;
 use App\Models\OrderLog;
+use App\Models\OrderProduct;
 use App\Services\OrderService as EndpointOrderService;
 
 class OrderService
@@ -19,15 +20,44 @@ class OrderService
     public function adminReduceOrder(Order $order, int $reduceAmount)
     {
         if ($order->isPending()) {
+            $needReduceAmount = $order->total_amount - $reduceAmount + $order->reduced_amount;
             $res = $order->where('updated_at', $order->updated_at)->update([
-                'reduced_amount' => $order->total_amount - $reduceAmount + $order->reduced_amount,
+                'reduced_amount' => $needReduceAmount,
                 'total_amount' => $reduceAmount,
             ]);
             if ($res === 0) {
                 throw new BizException('订单已发生改变');
             }
 
-            //更新订单商品优惠金额-todo
+            //更新订单商品优惠金额
+            //分解到订单中除赠品外的商品
+            $orderProducts = $order->products;
+            $needReduceOrderProducts = [];
+            foreach ($orderProducts as $orderProduct) {
+                if (!$orderProduct->isGift()) {
+                    $needReduceOrderProducts[$orderProduct->id] = $orderProduct->total_amount;
+                }
+            }
+
+            $i = count($needReduceOrderProducts);
+            $totalAmount = array_sum($needReduceOrderProducts);
+            foreach ($needReduceOrderProducts as $key => $reduceOrderProductAmount) {
+                $i --;
+
+                if ($i > 0) {
+                    $amount = (int) bcdiv(bcmul($needReduceAmount, $reduceOrderProductAmount, 0), $totalAmount, 2);
+                    $needReduceAmount -= $amount;
+                    $totalAmount -= $reduceOrderProductAmount;
+                } else {
+                    $amount = $needReduceAmount;
+                }
+
+                //更新订单商品的金额
+                OrderProduct::where('id', $key)->update([
+                    'reduced_amount' => $amount,
+                    'total_amount'  => $reduceOrderProductAmount - $amount,
+                ]);
+            }
 
             OrderLog::create([
                 'order_id'=>$order->id,