perf: eliminate per-message DB hits and redundant Telegram API calls

- IsUserApproved: use cached approved-user list instead of per-call DB point lookup (called 8x per message across hot-path handlers)
- canBot{Restrict,Promote,Pin,Delete}: reuse admin cache via getUserMemberWithCache instead of independent GetMember API calls per check
- Add functional index on filters(chat_id, LOWER(keyword)) to fix full-scan on DoesFilterExists
- Add warns_users(chat_id) index for chat-only warn lookups bypassed by existing user_id-leading composite index

Author: Divkix

alita/db/approvals/repository.go

@@ -29,9 +29,12 @@ func AddApprovedUser(chatID, userID, approvedBy int64, reason string) error {
 
 // IsUserApproved checks if a user is in the approved list for a chat.
 func IsUserApproved(chatID, userID int64) bool {
-	var user models.ApprovedUsers
-	err := db.GetRecord(&user, models.ApprovedUsers{ChatID: chatID, UserID: userID})
-	return err == nil
+	for _, u := range GetApprovedUsers(chatID) {
+		if u.UserID == userID {
+			return true
+		}
+	}
+	return false
 }
 
 // GetApprovedUsers returns all approved users for a chat.

alita/utils/chat_status/access.go

@@ -82,11 +82,11 @@ func canBotRestrict(b *gotgbot.Bot, ctx *ext.Context, chat *gotgbot.Chat) bool {
 		return false
 	}
 
-	botMember, err := chat.GetMember(b, b.Id, nil)
-	if err != nil {
+	botMember, ok := getUserMemberWithCache(b, chat, b.Id, "canBotRestrict")
+	if !ok {
 		return false
 	}
-	return botMember.MergeChatMember().CanRestrictMembers
+	return botMember.CanRestrictMembers
 }
 
 // canBotPromote reports whether the bot can promote/demote members.
@@ -99,11 +99,11 @@ func canBotPromote(b *gotgbot.Bot, ctx *ext.Context, chat *gotgbot.Chat) bool {
 		return false
 	}
 
-	botMember, err := chat.GetMember(b, b.Id, nil)
-	if err != nil {
+	botMember, ok := getUserMemberWithCache(b, chat, b.Id, "canBotPromote")
+	if !ok {
 		return false
 	}
-	return botMember.MergeChatMember().CanPromoteMembers
+	return botMember.CanPromoteMembers
 }
 
 // canBotPin reports whether the bot can pin messages.
@@ -116,11 +116,11 @@ func canBotPin(b *gotgbot.Bot, ctx *ext.Context, chat *gotgbot.Chat) bool {
 		return false
 	}
 
-	botMember, err := chat.GetMember(b, b.Id, nil)
-	if err != nil {
+	botMember, ok := getUserMemberWithCache(b, chat, b.Id, "canBotPin")
+	if !ok {
 		return false
 	}
-	return botMember.MergeChatMember().CanPinMessages
+	return botMember.CanPinMessages
 }
 
 // canBotDelete reports whether the bot can delete messages.
@@ -133,11 +133,11 @@ func canBotDelete(b *gotgbot.Bot, ctx *ext.Context, chat *gotgbot.Chat) bool {
 		return false
 	}
 
-	botMember, err := chat.GetMember(b, b.Id, nil)
-	if err != nil {
+	botMember, ok := getUserMemberWithCache(b, chat, b.Id, "canBotDelete")
+	if !ok {
 		return false
 	}
-	return botMember.MergeChatMember().CanDeleteMessages
+	return botMember.CanDeleteMessages
 }
 
 // isBotAdminPure reports whether the bot is an admin, without sending messages.

migrations/20260609120000_add_filters_functional_index.sql

@@ -0,0 +1,42 @@
+-- =====================================================
+-- FILTERS FUNCTIONAL INDEX & WARNS CHAT INDEX
+-- =====================================================
+-- This migration adds targeted indexes to eliminate full-table scans
+-- on high-frequency filter watcher and warn lookup queries.
+--
+-- NOTE: Uses regular CREATE INDEX (without CONCURRENTLY) to remain
+-- compatible with Supabase migration system which runs in transactions.
+
+-- =====================================================
+-- 1. FILTERS - Functional index for case-insensitive keyword lookup
+-- =====================================================
+-- DoesFilterExists queries: WHERE chat_id = ? AND LOWER(keyword) = LOWER(?)
+-- The existing idx_filters_chat_optimized ON filters(chat_id) only covers
+-- the chat_id predicate. Without a functional index on LOWER(keyword),
+-- PostgreSQL must heap-scan every filter row for the chat to evaluate
+-- the LOWER(keyword) expression on every filter-watcher message.
+-- This composite functional index lets PostgreSQL resolve both predicates
+-- entirely from the index, eliminating the heap scan.
+CREATE INDEX IF NOT EXISTS idx_filters_chat_keyword_lower
+ON filters(chat_id, LOWER(keyword));
+
+-- =====================================================
+-- 2. WARNS USERS - Chat-only lookup index
+-- =====================================================
+-- GetAllChatWarns and ResetAllChatWarns query: WHERE chat_id = ?
+-- The existing idx_warns_users_composite ON warns_users(user_id, chat_id)
+-- leads with user_id, so PostgreSQL cannot use it for chat_id-only lookups.
+-- This index allows efficient scans when only chat_id is provided.
+CREATE INDEX IF NOT EXISTS idx_warns_users_chat_id
+ON warns_users(chat_id);
+
+-- =====================================================
+-- 3. UPDATE TABLE STATISTICS
+-- =====================================================
+ANALYZE filters;
+ANALYZE warns_users;
+
+DO $$
+BEGIN
+    RAISE NOTICE 'Filters functional index and warns chat index migration completed successfully';
+END $$;