add unit suggestion based on ingredient

backend/routes/recipes.js

@@ -65,6 +65,52 @@ router.get('/ingredients/suggestions', async (req, res) => {
   }
 });
 
+// Get unit suggestions for a specific ingredient
+router.get('/ingredients/units', async (req, res) => {
+  try {
+    const { ingredient } = req.query;
+    
+    if (!ingredient) {
+      return res.json([]);
+    }
+    
+    // Find units used with this specific ingredient
+    const unitSuggestions = await Recipe.aggregate([
+      { $unwind: '$ingredients' },
+      { 
+        $match: { 
+          'ingredients.name': { 
+            $regex: ingredient, 
+            $options: 'i' 
+          } 
+        } 
+      },
+      { 
+        $group: { 
+          _id: { $toLower: '$ingredients.unit' },
+          unit: { $first: '$ingredients.unit' },
+          count: { $sum: 1 },
+          avgAmount: { $avg: '$ingredients.amount' }
+        } 
+      },
+      { $sort: { count: -1, unit: 1 } },
+      { $limit: 8 },
+      { 
+        $project: { 
+          _id: 0, 
+          unit: 1, 
+          count: 1,
+          avgAmount: { $round: ['$avgAmount', 2] }
+        } 
+      }
+    ]);
+    
+    res.json(unitSuggestions);
+  } catch (error) {
+    res.status(500).json({ error: error.message });
+  }
+});
+
 // Get all recipes
 router.get('/', async (req, res) => {
   try {