update stat

lib/pages/stats.dart

@@ -1,4 +1,5 @@
 import 'package:cdb_ui/api.dart';
+import 'package:cdb_ui/pages/expandable_list.dart';
 import 'package:cdb_ui/pages/transaction.dart';
 import 'package:flutter/material.dart';
 
@@ -85,16 +86,48 @@ class ItemStatPage extends StatelessWidget {
 
   const ItemStatPage(this.item, {super.key});
 
-  // todo : expiry ratio
   // todo : avg time of transaction active
 
+  ExpandableListItem buildVariantStat(String variant) {
+    return ExpandableListItem(
+        body: FutureBuilder(
+          future: API().getStat(item.id, variant, full: true),
+          builder: (context, snapshot) {
+            if (!snapshot.hasData) {
+              return const CircularProgressIndicator();
+            }
+
+            var data = snapshot.data! as FullItemVariantStat;
+
+            return Column(
+              children: [
+                Text("Amount: ${data.amount}"),
+                Text("Total Cost: ${data.totalPrice}"),
+                Text("Expiry Rate: ${data.expiryRate}"),
+                ...data.origins.keys.map((key) {
+                  var originStat = data.origins[key]!;
+                  return Column(children: [
+                    Text("Inventory: ${originStat.inventory}"),
+                    Text(
+                        "Average Price: ${originStat.average_price.toStringAsFixed(2)} €"),
+                  ]);
+                }).toList()
+              ],
+            );
+          },
+        ),
+        header: Text(item.variants[variant]!.name));
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
         title: Text("Statistics of ${item.name}"),
       ),
-      body: null,
+      body: Column(children: [
+        ExpandableList(item.variants.keys.map(buildVariantStat).toList())
+      ]),
     );
   }
 }