What is the original work of the movie Big Fish Begonia?

The movie was originally based on the novel " Big Fish and Begonia ". The novel was set in the future and told the love story between a young female mage and a big fish named " Begonia." In the story, Haitang sacrificed herself to save mankind, but left behind a mysterious magic box that could fulfill human wishes. The plot of the novel was full of ups and downs, and the characters were rich. It was a literary work full of imagination and emotional depth.