Help me find this movie, it's european

It basically starts with two best friends, one of them is redheaded and wears glasses. He somehow ends up going inside a beer keg/barrel in a strong river and he ends up in a different country in a carneval full of magicians, a fortune teller etc. He meets a girl that looks Arabic and falls in love with her. He also needs to find some ring or diamond and then people from that carneval start chasing him. In the end I think he goes back to his own country.
I think it could have been a Czech movie but I’m not sure. I can’t find any information on Google, please help me. It’s very adventurous and the title includes a complicated name