Add UPC validation and automatic item number generation/validation

inventory-server/src/routes/import.js

@@ -899,6 +899,100 @@ router.get('/search-products', async (req, res) => {
   }
 });
 
+// Endpoint to check UPC and generate item number
+router.get('/check-upc-and-generate-sku', async (req, res) => {
+  const { upc, supplierId } = req.query;
+  
+  if (!upc || !supplierId) {
+    return res.status(400).json({ error: 'UPC and supplier ID are required' });
+  }
+  
+  try {
+    const { connection } = await getDbConnection();
+    
+    // Step 1: Check if the UPC already exists
+    const [upcCheck] = await connection.query(
+      'SELECT pid, itemnumber FROM products WHERE upc = ? LIMIT 1',
+      [upc]
+    );
+    
+    if (upcCheck.length > 0) {
+      return res.status(409).json({ 
+        error: 'UPC already exists', 
+        existingProductId: upcCheck[0].pid,
+        existingItemNumber: upcCheck[0].itemnumber
+      });
+    }
+    
+    // Step 2: Generate item number - supplierId-last6DigitsOfUPC minus last digit
+    let itemNumber = '';
+    const upcStr = String(upc);
+    
+    // Extract the last 6 digits of the UPC, removing the last digit (checksum)
+    // So we get 5 digits from positions: length-7 to length-2
+    if (upcStr.length >= 7) {
+      const lastSixMinusOne = upcStr.substring(upcStr.length - 7, upcStr.length - 1);
+      itemNumber = `${supplierId}-${lastSixMinusOne}`;
+    } else if (upcStr.length >= 6) {
+      // If UPC is shorter, use as many digits as possible
+      const digitsToUse = upcStr.substring(0, upcStr.length - 1);
+      itemNumber = `${supplierId}-${digitsToUse}`;
+    } else {
+      // Very short UPC, just use the whole thing
+      itemNumber = `${supplierId}-${upcStr}`;
+    }
+    
+    // Step 3: Check if the generated item number exists
+    const [itemNumberCheck] = await connection.query(
+      'SELECT pid FROM products WHERE itemnumber = ? LIMIT 1',
+      [itemNumber]
+    );
+    
+    // Step 4: If the item number exists, modify it to use the last 5 digits of the UPC
+    if (itemNumberCheck.length > 0) {
+      console.log(`Item number ${itemNumber} already exists, using alternative format`);
+      
+      if (upcStr.length >= 5) {
+        // Use the last 5 digits (including the checksum)
+        const lastFive = upcStr.substring(upcStr.length - 5);
+        itemNumber = `${supplierId}-${lastFive}`;
+        
+        // Check again if this new item number also exists
+        const [altItemNumberCheck] = await connection.query(
+          'SELECT pid FROM products WHERE itemnumber = ? LIMIT 1',
+          [itemNumber]
+        );
+        
+        if (altItemNumberCheck.length > 0) {
+          // If even the alternative format exists, add a timestamp suffix for uniqueness
+          const timestamp = Date.now().toString().substring(8, 13); // Get last 5 digits of timestamp
+          itemNumber = `${supplierId}-${timestamp}`;
+          console.log(`Alternative item number also exists, using timestamp: ${itemNumber}`);
+        }
+      } else {
+        // For very short UPCs, add a timestamp
+        const timestamp = Date.now().toString().substring(8, 13); // Get last 5 digits of timestamp
+        itemNumber = `${supplierId}-${timestamp}`;
+      }
+    }
+    
+    // Return the generated item number
+    res.json({ 
+      success: true, 
+      itemNumber, 
+      upc,
+      supplierId
+    });
+    
+  } catch (error) {
+    console.error('Error checking UPC and generating item number:', error);
+    res.status(500).json({ 
+      error: 'Failed to check UPC and generate item number',
+      details: error.message
+    });
+  }
+});
+
 // Get product categories for a specific product
 router.get('/product-categories/:pid', async (req, res) => {
   try {