This is an example of chiasmus, a rhetorical figure in which the structure of the first clause is reversed in the second clause, in an AB-BA pattern. One of the most famous examples comes from John F. Kennedy's presidential inauguration speech:
Ask not what your country can do for you; ask what you can do for your country.
This device is powerful, as are most rhetorical devices, and one should take care in using them. Idle usage can sound silly or pompous. As Ward Farnsworth notes in his exemplary Classical English Rhetoric:
A chiasmus that reverses the same words ... calls attention to itself strongly, and so must be used with particular care ... In the hands of a typical modern politician, [it] will sound disagreeably slick and perhaps even repulsive.
There is nothing ungrammatical about the usage in your example, but it sounds odd here because its power is way out of proportion to the simple and somewhat insipid greeting it's used to express.