feat: [商品管理] 優化商品匯入邏輯，支援 13 碼條碼自動生成、Upsert 更新機制與 Excel 說明工作表

app/Modules/Inventory/Imports/ProductImport.php

@@ -57,21 +57,25 @@ class ProductImport implements ToModel, WithHeadingRow, WithValidation, WithMapp
         $baseUnitId = $this->units[$row['基本單位']] ?? null;
         $largeUnitId = isset($row['大單位']) ? ($this->units[$row['大單位']] ?? null) : null;
 
-
         // 若必要關聯找不到，理論上 Validation 會攔截，但此處做防禦性編程
         if (!$categoryId || !$baseUnitId) {
             return null;
         }
 
-        // 處理商品代號：若為空則自動生成
         $code = $row['商品代號'] ?? null;
-        if (empty($code)) {
-            $code = $this->generateRandomCode();
+        $barcode = $row['條碼'] ?? null;
+
+        // Upsert 邏輯：優先以條碼查找，次之以商品代號查找
+        $product = null;
+        if (!empty($barcode)) {
+            $product = Product::where('barcode', $barcode)->first();
         }
 
-        return new Product([
-            'code' => $code,
-            'barcode' => $row['條碼'],
+        if (!$product && !empty($code)) {
+            $product = Product::where('code', $code)->first();
+        }
+
+        $data = [
             'name' => $row['商品名稱'],
             'category_id' => $categoryId,
             'brand' => $row['品牌'] ?? null,
@@ -84,7 +88,26 @@ class ProductImport implements ToModel, WithHeadingRow, WithValidation, WithMapp
             'price' => $row['售價'] ?? null,
             'member_price' => $row['會員價'] ?? null,
             'wholesale_price' => $row['批發價'] ?? null,
-        ]);
+        ];
+
+        if ($product) {
+            // 更新現有商品
+            $product->update($data);
+            return null; // 返回 null 以避免 Maatwebsite/Excel 嘗試再次 insert
+        }
+
+        // 建立新商品：處理代碼與條碼自動生成
+        if (empty($code)) {
+            $code = $this->generateRandomCode();
+        }
+        if (empty($barcode)) {
+            $barcode = $this->generateRandomBarcode();
+        }
+
+        $data['code'] = $code;
+        $data['barcode'] = $barcode;
+
+        return new Product($data);
     }
 
     /**
@@ -105,11 +128,28 @@ class ProductImport implements ToModel, WithHeadingRow, WithValidation, WithMapp
         return $code;
     }
 
+    /**
+     * 生成隨機 13 碼條碼 (純數字)
+     */
+    private function generateRandomBarcode(): string
+    {
+        $barcode = '';
+        
+        do {
+            $barcode = '';
+            for ($i = 0; $i < 13; $i++) {
+                $barcode .= rand(0, 9);
+            }
+        } while (Product::where('barcode', $barcode)->exists());
+
+        return $barcode;
+    }
+
     public function rules(): array
     {
         return [
-            '商品代號' => ['nullable', 'string', 'min:2', 'max:8', 'unique:products,code'],
-            '條碼' => ['required', 'string', 'unique:products,barcode'],
+            '商品代號' => ['nullable', 'string', 'min:2', 'max:8'],
+            '條碼' => ['nullable', 'string'],
             '商品名稱' => ['required', 'string'],
             '類別名稱' => ['required', function($attribute, $value, $fail) {
                 if (!isset($this->categories[$value])) {