(I thought the demand for this would drop after the website's new duplicate feature. Since they have all the back end, they can do it instantly. But turns out it doesn't duplicate after 999 messages. So it still has a purpose to serve. Alongside chat imports of course.)
A new FASTER method of cloning chats is added. Kept the old one as well just in case
Added options and the message list to clone up to a certain point or a range
NEW METHOD:
1000 messages = around 13 minutes
Remembers Pinned
Progress looks better and is more informative
I guess more vulnerable to internet connection problems but I will address that later
CLARIFICATION:
Many people came to me complaining how failed/interrupted cloning destroyed the original but that's a misunderstanding and it's completely my fault I didn't explain it clearly.
What happens is that the URL of the chat page doesn't have the chat id unless you go to the chat from the history. That's why it brings you the latest interracted chat, which is the clone. The original chat is in the history and it's never touched. New method updates the URL so when you refresh you are still in the original chat. It also has link to the original