Add SQLite database for Telegram bot user/group settings

- Replace Redis/in-memory storage with SQLite for persistence
- Add database.ts service with tables for users, groups, purchases, participants
- Update state.ts and groupState.ts to use SQLite backend
- Fix buyer_name to use display name instead of Telegram ID
- Remove legacy reminder array handlers (now using 3-slot system)
- Add better-sqlite3 dependency, remove ioredis
- Update env.example with BOT_DATABASE_PATH option
- Add data/ directory to .gitignore for database files

telegram_bot/src/handlers/settings.ts

@@ -0,0 +1,172 @@
+import TelegramBot from 'node-telegram-bot-api';
+import { stateManager } from '../services/state';
+import { logger, logUserAction } from '../services/logger';
+import { messages } from '../messages';
+import { getMainMenuKeyboard, getSettingsKeyboard } from '../utils/keyboards';
+import { NotificationPreferences, DEFAULT_NOTIFICATIONS } from '../types';
+
+/**
+ * Handle /settings command (private chat only)
+ */
+export async function handleSettingsCommand(
+  bot: TelegramBot,
+  msg: TelegramBot.Message
+): Promise<void> {
+  const chatId = msg.chat.id;
+  const userId = msg.from?.id;
+
+  if (!userId) return;
+
+  // Only works in private chats
+  if (msg.chat.type !== 'private') {
+    await bot.sendMessage(chatId, '❌ This command only works in private chat. Message me directly!');
+    return;
+  }
+
+  logUserAction(userId, 'Viewed settings');
+
+  const user = await stateManager.getUser(userId);
+  if (!user) {
+    await bot.sendMessage(chatId, messages.errors.startFirst, {
+      reply_markup: getMainMenuKeyboard(),
+    });
+    return;
+  }
+
+  // Ensure notifications object exists
+  const notifications = user.notifications || { ...DEFAULT_NOTIFICATIONS };
+  const displayName = user.displayName || 'Anon';
+
+  await bot.sendMessage(
+    chatId,
+    messages.settings.overview(displayName, notifications),
+    {
+      parse_mode: 'Markdown',
+      reply_markup: getSettingsKeyboard(displayName, notifications),
+    }
+  );
+}
+
+/**
+ * Handle settings callback
+ */
+export async function handleSettingsCallback(
+  bot: TelegramBot,
+  query: TelegramBot.CallbackQuery,
+  action: string
+): Promise<void> {
+  const chatId = query.message?.chat.id;
+  const userId = query.from.id;
+  const messageId = query.message?.message_id;
+
+  if (!chatId || !messageId) return;
+
+  const user = await stateManager.getUser(userId);
+  if (!user) {
+    await bot.answerCallbackQuery(query.id, { text: 'Please /start first' });
+    return;
+  }
+
+  try {
+    // Handle notification toggles
+    if (action.startsWith('toggle_notif_')) {
+      const setting = action.replace('toggle_notif_', '') as keyof NotificationPreferences;
+      const currentNotifications = user.notifications || { ...DEFAULT_NOTIFICATIONS };
+      const newValue = !currentNotifications[setting];
+      
+      const updatedUser = await stateManager.updateNotifications(userId, { [setting]: newValue });
+      
+      if (updatedUser) {
+        logUserAction(userId, 'Updated notification setting', { setting, newValue });
+        await bot.answerCallbackQuery(query.id, {
+          text: `${setting} ${newValue ? 'enabled' : 'disabled'}`,
+        });
+
+        // Update message
+        await bot.editMessageText(
+          messages.settings.overview(updatedUser.displayName || 'Anon', updatedUser.notifications),
+          {
+            chat_id: chatId,
+            message_id: messageId,
+            parse_mode: 'Markdown',
+            reply_markup: getSettingsKeyboard(updatedUser.displayName || 'Anon', updatedUser.notifications),
+          }
+        );
+      }
+      return;
+    }
+
+    // Handle display name change
+    if (action === 'change_name') {
+      await bot.answerCallbackQuery(query.id);
+      await stateManager.updateUserState(userId, 'awaiting_display_name');
+      await bot.sendMessage(
+        chatId,
+        messages.settings.enterDisplayName,
+        { parse_mode: 'Markdown' }
+      );
+      return;
+    }
+
+    // Handle back to menu
+    if (action === 'back_menu') {
+      await bot.answerCallbackQuery(query.id);
+      await bot.deleteMessage(chatId, messageId);
+      await bot.sendMessage(chatId, messages.menu.header, {
+        parse_mode: 'Markdown',
+        reply_markup: getMainMenuKeyboard(),
+      });
+      return;
+    }
+
+    await bot.answerCallbackQuery(query.id);
+  } catch (error) {
+    logger.error('Error in handleSettingsCallback', { error, userId, action });
+    await bot.answerCallbackQuery(query.id, { text: 'Error updating settings' });
+  }
+}
+
+/**
+ * Handle display name input
+ */
+export async function handleDisplayNameInput(
+  bot: TelegramBot,
+  msg: TelegramBot.Message
+): Promise<void> {
+  const chatId = msg.chat.id;
+  const userId = msg.from?.id;
+  const text = msg.text?.trim();
+
+  if (!userId || !text) return;
+
+  // Validate display name (max 20 chars, alphanumeric + spaces + some symbols)
+  if (text.length > 20) {
+    await bot.sendMessage(chatId, messages.settings.nameTooLong);
+    return;
+  }
+
+  // Clean the display name
+  const cleanName = text.replace(/[^\w\s\-_.]/g, '').trim() || 'Anon';
+
+  await stateManager.updateDisplayName(userId, cleanName);
+  logUserAction(userId, 'Set display name', { displayName: cleanName });
+
+  const user = await stateManager.getUser(userId);
+  const notifications = user?.notifications || { ...DEFAULT_NOTIFICATIONS };
+
+  await bot.sendMessage(
+    chatId,
+    messages.settings.nameUpdated(cleanName),
+    {
+      parse_mode: 'Markdown',
+      reply_markup: getSettingsKeyboard(cleanName, notifications),
+    }
+  );
+}
+
+export default {
+  handleSettingsCommand,
+  handleSettingsCallback,
+  handleDisplayNameInput,
+};
+