complete account page

Billing.Shared/Views/AccountPage.xaml.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using Billing.Models;
 using Billing.UI;
 using Xamarin.Forms;
@@ -20,17 +21,57 @@ namespace Billing.Views
 
         public Command AddAccount { get; }
 
-        private readonly List<AccountGrouping> accounts;
+        private readonly List<AccountGrouping> accounts = new();
+        private bool initialized;
 
         public AccountPage()
         {
             AddAccount = new Command(OnAddAccount);
-            accounts = new List<AccountGrouping>();
             SetValue(AccountsProperty, accounts);
 
             InitializeComponent();
         }
 
+        protected override void OnAppearing()
+        {
+            if (!initialized)
+            {
+                initialized = true;
+                accounts.Clear();
+                foreach (var account in App.Accounts)
+                {
+                    AddToAccountGroup(account);
+                }
+            }
+            groupLayout.Refresh(accounts);
+        }
+
+        private void AddToAccountGroup(Account account)
+        {
+            int maxId;
+            if (accounts.Count > 0)
+            {
+                maxId = accounts.Max(g => g.Max(a => a.Id));
+            }
+            else
+            {
+                maxId = -1;
+            }
+            account.Id = maxId + 1;
+
+            var group = accounts.FirstOrDefault(g => g.Key == account.Category);
+            if (group == null)
+            {
+                group = new AccountGrouping(account.Category, account.Balance) { account };
+                accounts.Add(group);
+            }
+            else
+            {
+                group.Add(account);
+                group.Balance += account.Balance;
+            }
+        }
+
         private async void OnAddAccount()
         {
             if (Tap.IsBusy)
@@ -47,28 +88,23 @@ namespace Billing.Views
 
         private void AccountChecked(object sender, AccountEventArgs e)
         {
-            Helper.Debug(e.Account.ToString());
-            var group = accounts.FirstOrDefault(g => g.Key == e.Account.Category);
-            if (group == null)
-            {
-                group = new AccountGrouping(e.Account.Category)
-                {
-                    e.Account
-                };
-                accounts.Add(group);
-            }
-            else
-            {
-                group.Add(e.Account);
-            }
+            App.Accounts.Add(e.Account);
+            AddToAccountGroup(e.Account);
             groupLayout.Refresh(accounts);
+
+            Task.Run(App.WriteAccounts);
         }
     }
 
     public class AccountGrouping : List<Account>, IGrouping<AccountCategory, Account>
     {
-        public AccountGrouping(AccountCategory key) : base() => Key = key;
         public AccountCategory Key { get; }
         public decimal Balance { get; set; }
+
+        public AccountGrouping(AccountCategory key, decimal balance) : base()
+        {
+            Key = key;
+            Balance = balance;
+        }
     }
 }