Feature: Add postal address memory with user preference

- Added SavedShippingAddress model to store user addresses
- Added Privacy.SaveShippingAddress preference (null = not asked, true/false = user choice)
- Enhanced checkout flow to offer using saved address if available
- Ask once about saving address, respect user's choice going forward
- Automatically save/not save based on user preference in future orders
- Added menu options: Use Saved Address, Enter New Address, Save Address (Yes/No)
- Enhanced CallbackHandler with save address handlers
- Updated MessageHandler to prompt for save preference on first use

User will only be asked once about saving addresses. Account reset clears preference.

TeleBot/TeleBot/Handlers/CallbackHandler.cs

@@ -140,6 +140,22 @@ namespace TeleBot.Handlers
                         await HandleCheckout(bot, callbackQuery.Message, session);
                         break;
 
+                    case "use_saved_address":
+                        await HandleUseSavedAddress(bot, callbackQuery.Message, session);
+                        break;
+
+                    case "enter_new_address":
+                        await HandleEnterNewAddress(bot, callbackQuery.Message, session);
+                        break;
+
+                    case "save_address_yes":
+                        await HandleSaveAddressPreference(bot, callbackQuery.Message, session, true);
+                        break;
+
+                    case "save_address_no":
+                        await HandleSaveAddressPreference(bot, callbackQuery.Message, session, false);
+                        break;
+
                     case "confirm_order":
                         await HandleConfirmOrder(bot, callbackQuery.Message, session, callbackQuery.From);
                         break;
@@ -746,9 +762,81 @@ namespace TeleBot.Handlers
 
             session.State = SessionState.CheckoutFlow;
 
-            // Send new message for checkout - collect all details at once
+            // Check if user has saved address
-            await bot.SendTextMessageAsync(
+            if (session.SavedAddress != null && !string.IsNullOrWhiteSpace(session.SavedAddress.Name))
+            {
+                // Offer to use saved address
+                var savedAddressPreview = $"{session.SavedAddress.Name}\n" +
+                                         $"{session.SavedAddress.Address}\n" +
+                                         $"{session.SavedAddress.City}\n" +
+                                         $"{session.SavedAddress.PostCode}\n" +
+                                         $"{session.SavedAddress.Country}";
+
+                await bot.SendTextMessageAsync(
+                    message.Chat.Id,
+                    $"📦 *Checkout - Delivery Details*\n\n" +
+                    $"Use your saved address?\n\n" +
+                    $"```\n{savedAddressPreview}\n```",
+                    parseMode: Telegram.Bot.Types.Enums.ParseMode.Markdown,
+                    replyMarkup: _menuBuilder.UseSavedAddressMenu()
+                );
+            }
+            else
+            {
+                // Send new message for checkout - collect all details at once
+                await bot.SendTextMessageAsync(
+                    message.Chat.Id,
+                    "📦 *Checkout - Delivery Details*\n\n" +
+                    "Please provide all delivery details in one message:\n\n" +
+                    "• Full Name\n" +
+                    "• Street Address\n" +
+                    "• City\n" +
+                    "• Post/Zip Code\n" +
+                    "• Country (or leave blank for UK)\n\n" +
+                    "_Example:_\n" +
+                    "`John Smith\n" +
+                    "123 Main Street\n" +
+                    "London\n" +
+                    "SW1A 1AA\n" +
+                    "United Kingdom`",
+                    parseMode: Telegram.Bot.Types.Enums.ParseMode.Markdown
+                );
+            }
+        }
+
+        private async Task HandleUseSavedAddress(ITelegramBotClient bot, Message message, UserSession session)
+        {
+            if (session.SavedAddress == null || session.OrderFlow == null)
+            {
+                await HandleEnterNewAddress(bot, message, session);
+                return;
+            }
+
+            // Copy saved address to order flow
+            session.OrderFlow.ShippingName = session.SavedAddress.Name;
+            session.OrderFlow.ShippingAddress = session.SavedAddress.Address;
+            session.OrderFlow.ShippingCity = session.SavedAddress.City;
+            session.OrderFlow.ShippingPostCode = session.SavedAddress.PostCode;
+            session.OrderFlow.ShippingCountry = session.SavedAddress.Country;
+            session.OrderFlow.CurrentStep = OrderFlowStep.ReviewingOrder;
+
+            // Show order summary
+            var summary = MessageFormatter.FormatOrderSummary(session.OrderFlow, session.Cart);
+
+            await bot.EditMessageTextAsync(
                 message.Chat.Id,
+                message.MessageId,
+                summary,
+                parseMode: Telegram.Bot.Types.Enums.ParseMode.Markdown,
+                replyMarkup: MenuBuilder.CheckoutConfirmMenu()
+            );
+        }
+
+        private async Task HandleEnterNewAddress(ITelegramBotClient bot, Message message, UserSession session)
+        {
+            await bot.EditMessageTextAsync(
+                message.Chat.Id,
+                message.MessageId,
                 "📦 *Checkout - Delivery Details*\n\n" +
                 "Please provide all delivery details in one message:\n\n" +
                 "• Full Name\n" +
@@ -766,6 +854,41 @@ namespace TeleBot.Handlers
             );
         }
 
+        private async Task HandleSaveAddressPreference(ITelegramBotClient bot, Message message, UserSession session, bool saveAddress)
+        {
+            // Save user preference
+            session.Privacy.SaveShippingAddress = saveAddress;
+
+            if (saveAddress && session.OrderFlow != null)
+            {
+                // Save the address
+                session.SavedAddress = new SavedShippingAddress
+                {
+                    Name = session.OrderFlow.ShippingName,
+                    Address = session.OrderFlow.ShippingAddress,
+                    City = session.OrderFlow.ShippingCity,
+                    PostCode = session.OrderFlow.ShippingPostCode,
+                    Country = session.OrderFlow.ShippingCountry,
+                    SavedAt = DateTime.UtcNow
+                };
+            }
+
+            // Continue to order summary
+            if (session.OrderFlow != null)
+            {
+                session.OrderFlow.CurrentStep = OrderFlowStep.ReviewingOrder;
+                var summary = MessageFormatter.FormatOrderSummary(session.OrderFlow, session.Cart);
+
+                await bot.EditMessageTextAsync(
+                    message.Chat.Id,
+                    message.MessageId,
+                    summary,
+                    parseMode: Telegram.Bot.Types.Enums.ParseMode.Markdown,
+                    replyMarkup: MenuBuilder.CheckoutConfirmMenu()
+                );
+            }
+        }
+
         private async Task HandleConfirmOrder(ITelegramBotClient bot, Message message, UserSession session, User telegramUser)
         {
             if (session.OrderFlow == null || session.Cart.IsEmpty())

TeleBot/TeleBot/Handlers/MessageHandler.cs

@@ -132,18 +132,48 @@ namespace TeleBot.Handlers
                         ? lines[4]
                         : "United Kingdom";
 
-                    // Skip to review step
+                    // Check if we need to ask about saving address
-                    session.OrderFlow.CurrentStep = OrderFlowStep.ReviewingOrder;
+                    if (session.Privacy.SaveShippingAddress == null)
+                    {
+                        // Haven't asked yet - offer to save
+                        await bot.SendTextMessageAsync(
+                            message.Chat.Id,
+                            "💾 *Save Address*\n\n" +
+                            "Would you like to save this address for future orders?\n\n" +
+                            "_You will only be asked this once._",
+                            parseMode: Telegram.Bot.Types.Enums.ParseMode.Markdown,
+                            replyMarkup: new MenuBuilder(null!).SaveAddressConfirmMenu()
+                        );
+                    }
+                    else
+                    {
+                        // Already has preference - apply it automatically
+                        if (session.Privacy.SaveShippingAddress == true)
+                        {
+                            session.SavedAddress = new SavedShippingAddress
+                            {
+                                Name = session.OrderFlow.ShippingName,
+                                Address = session.OrderFlow.ShippingAddress,
+                                City = session.OrderFlow.ShippingCity,
+                                PostCode = session.OrderFlow.ShippingPostCode,
+                                Country = session.OrderFlow.ShippingCountry,
+                                SavedAt = DateTime.UtcNow
+                            };
+                        }
 
-                    // Show order summary
+                        // Skip to review step
-                    var summary = MessageFormatter.FormatOrderSummary(session.OrderFlow, session.Cart);
+                        session.OrderFlow.CurrentStep = OrderFlowStep.ReviewingOrder;
 
-                    await bot.SendTextMessageAsync(
+                        // Show order summary
-                        message.Chat.Id,
+                        var summary = MessageFormatter.FormatOrderSummary(session.OrderFlow, session.Cart);
-                        summary,
+
-                        parseMode: Telegram.Bot.Types.Enums.ParseMode.Markdown,
+                        await bot.SendTextMessageAsync(
-                        replyMarkup: MenuBuilder.CheckoutConfirmMenu()
+                            message.Chat.Id,
-                    );
+                            summary,
+                            parseMode: Telegram.Bot.Types.Enums.ParseMode.Markdown,
+                            replyMarkup: MenuBuilder.CheckoutConfirmMenu()
+                        );
+                    }
                     break;
                     
                 // Legacy steps - redirect to new single-message collection

TeleBot/TeleBot/Models/UserSession.cs

@@ -25,6 +25,9 @@ namespace TeleBot.Models
         public bool IsEphemeral { get; set; } = true;
         public PrivacySettings Privacy { get; set; } = new();
 
+        // Saved shipping address (optional, based on user preference)
+        public SavedShippingAddress? SavedAddress { get; set; }
+
         // Order flow data (temporary)
         public OrderFlowData? OrderFlow { get; set; }
         
@@ -62,6 +65,19 @@ namespace TeleBot.Models
 
         public bool EnableDisappearingMessages { get; set; } = true;
         public int DisappearingMessageTTL { get; set; } = 30; // seconds
+
+        // Address memory preference
+        public bool? SaveShippingAddress { get; set; } = null; // null = not asked yet, true = save, false = don't save
+    }
+
+    public class SavedShippingAddress
+    {
+        public string? Name { get; set; }
+        public string? Address { get; set; }
+        public string? City { get; set; }
+        public string? PostCode { get; set; }
+        public string? Country { get; set; }
+        public DateTime? SavedAt { get; set; }
     }
     
     public class OrderFlowData

TeleBot/TeleBot/UI/MenuBuilder.cs

@@ -217,6 +217,35 @@ namespace TeleBot.UI
             });
         }
 
+        public InlineKeyboardMarkup UseSavedAddressMenu()
+        {
+            return new InlineKeyboardMarkup(new[]
+            {
+                new[] {
+                    InlineKeyboardButton.WithCallbackData("✅ Use Saved Address", "use_saved_address")
+                },
+                new[] {
+                    InlineKeyboardButton.WithCallbackData("✏️ Enter New Address", "enter_new_address")
+                },
+                new[] {
+                    InlineKeyboardButton.WithCallbackData("❌ Cancel", "cart")
+                }
+            });
+        }
+
+        public InlineKeyboardMarkup SaveAddressConfirmMenu()
+        {
+            return new InlineKeyboardMarkup(new[]
+            {
+                new[] {
+                    InlineKeyboardButton.WithCallbackData("✅ Yes, Save My Address", "save_address_yes")
+                },
+                new[] {
+                    InlineKeyboardButton.WithCallbackData("❌ No, Don't Save", "save_address_no")
+                }
+            });
+        }
+
         public static InlineKeyboardMarkup PaymentMethodMenu(List<string> currencies)
         {
             var buttons = new List<InlineKeyboardButton[]>();