From bfb1786a42bb21e3c24504378a7f646fddea2d7f Mon Sep 17 00:00:00 2001
From: Bohdan Horbeshko <bodqhrohro@gmail.com>
Date: Tue, 26 Aug 2025 13:10:20 -0400
Subject: [PATCH] Additional request for loading last messages

---
 telegram/utils.go | 37 +++++++++++++++++++++++++++----------
 1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/telegram/utils.go b/telegram/utils.go
index b127ae8..d6f8a20 100644
--- a/telegram/utils.go
+++ b/telegram/utils.go
@@ -2412,12 +2412,28 @@ func (c *Client) GetMessagesBetween(chatID, fromMessageId, lastMessageId int64,
 		Limit:         reqLimit,
 	})
 	if err == nil {
-		log.Debugf("pre-fetched %v messages, cutting", len(newMessages.Messages))
+		fetchedMessages := newMessages.Messages
+		log.Debugf("pre-fetched %v messages, cutting", len(fetchedMessages))
+
+		// it's not quite good to yield just one last message with the complete flag,
+		// as clients won't fetch more, give it one more chance
+		if limit < -1 && len(fetchedMessages) == 1 {
+			additionalMessages, err := c.client.GetChatHistory(&client.GetChatHistoryRequest{
+				ChatId:        chatID,
+				FromMessageId: fetchedMessages[0].Id,
+				Limit:         reqLimit-1,
+			})
+			if err == nil {
+				log.Debugf("fetched %v more messages", len(additionalMessages.Messages))
+				fetchedMessages = append(fetchedMessages, additionalMessages.Messages...)
+			}
+		}
+
 		if limit > 0 {
 			complete = true
 			fromPos := -1
 			if lastMessageId != 0 {
-				for i, message := range newMessages.Messages {
+				for i, message := range fetchedMessages {
 					if message.Id < lastMessageId {
 						complete = false
 						break
@@ -2427,32 +2443,33 @@ func (c *Client) GetMessagesBetween(chatID, fromMessageId, lastMessageId int64,
 					}
 				}
 			} else {
-				if len(newMessages.Messages) > 0 {
+				if len(fetchedMessages) > 0 {
 					lastMsg, lastMsgErr := c.GetPreviousMessage(chatID, 0)
 					if lastMsgErr == nil && lastMsg != nil {
-						if lastMsg.Id != newMessages.Messages[0].Id {
+						if lastMsg.Id != fetchedMessages[0].Id {
 							complete = false
 						}
 					}
 				}
 			}
 			if fromPos > -1 {
-				messages = newMessages.Messages[fromPos:]
+				messages = fetchedMessages[fromPos:]
 			} else {
-				messages = newMessages.Messages
+				messages = fetchedMessages
 			}
 		} else {
 			complete = true
-			for _, message := range newMessages.Messages {
+			for _, message := range fetchedMessages {
 				if message.Id <= fromMessageId {
 					break
 				}
 				messages = append(messages, message)
 			}
 		}
-	}
-	if !reverse {
-		ReverseMessagesSlice(messages)
+
+		if !reverse {
+			ReverseMessagesSlice(messages)
+		}
 	}
 	return
 }