Who knows the main idea of the poem Ghost Story?

There is a sentence in Lu's poem "Chang 'an Ancient Meaning" in the Tang Dynasty, "Why don't you give up your life if you succeed? Better be a mandarin duck than a fairy. " "I only envy Yuanyang, but I've never heard of it ..." This poem was written by Li Hanxiang, a director of Hong Kong film, because of Ghost Story, but the poem at that time was different from that listed by the landlord. Later, Tsui Hark rearranged and revised it, so it is the same as that sent by the landlord:

Li Edition: Shiliping Lake is full of blue sky, and Hosta secretly cherishes the New Year. If the rain covers can protect each other, they will only admire the mandarin ducks and not the immortals.

Xu Edition: first frost in Shiliping Lake, every inch of hair is sad for the New Year. Looking at the full moon and protecting each other, I only admire Yuanyang but not the fairy.