What's the story of "Drunkenness of the Imperial Lady"?

It's about Yang Guifei, the favorite of Emperor Xuanzong of the Tang Dynasty. One day, she invited Xuanzong to enjoy flowers and drink at Baihua Pavilion. Unexpectedly, she waited in the pavilion for a long time, and the eunuch came to tell her that Tang had gone to the West Palace. Yang Guifei was full of bitterness, so she had to drink alone in Baihua Pavilion to drown her sorrows, and she was intoxicated. This drama, also known as Baihua Pavilion, is a traditional drama with strong dance. After years of performance and revision, Mr. Mei Lanfang has many unique changes and has become a representative work of Mei School.