Adding items to cart

lib/tools/prefs.dart

@@ -0,0 +1,42 @@
+import 'dart:convert';
+
+import 'package:shared_preferences/shared_preferences.dart';
+
+Future<void> addItemToCart(String id) async {
+  final prefs = await SharedPreferences.getInstance();
+  String cartString = prefs.getString('cart') ?? "[]";
+  List<Map<String, dynamic>> cart =
+      List<Map<String, dynamic>>.from(jsonDecode(cartString) as List<dynamic>);
+  final index = cart.indexWhere((element) => element['id'] == id);
+  if (index == -1) {
+    cart.add({'id': id, 'count': 1});
+  } else {
+    cart[index]['count'] = cart[index]['count']! + 1;
+  }
+  prefs.setString('cart', jsonEncode(cart));
+}
+
+Future<List<Map<String, dynamic>>> getCart() async {
+  final prefs = await SharedPreferences.getInstance();
+  String cartString = prefs.getString('cart') ?? "[]";
+  List<Map<String, dynamic>> cart =
+      List<Map<String, dynamic>>.from(jsonDecode(cartString) as List<dynamic>);
+  return cart;
+}
+
+Future<void> removeItemFromCart(String id) async {
+  final prefs = await SharedPreferences.getInstance();
+  String cartString = prefs.getString('cart') ?? "[]";
+  List<Map<String, dynamic>> cart =
+      List<Map<String, dynamic>>.from(jsonDecode(cartString) as List<dynamic>);
+  cart.removeWhere((element) => element['id'] == id && element['count'] == 1);
+  for (final item in cart) {
+    if (item['id'] == id) {
+      item['count'] = item['count']! - 1;
+      if (item['count'] == 0) {
+        cart.remove(item);
+      }
+    }
+  }
+  prefs.setString('cart', jsonEncode(cart));
+}