FRAMINGHAM — A legend. An innovator. A model. A visionary. A god. The descriptors assigned to Sam Wong by public health leaders throughout the state universally reflect a profound admiration of a man who likely spent his last day as Framingham’s health director this week. The city announced late Tuesday that Wong is taking an indefinite medical leave from his post, one he’s held since 2017. He is unlikely to return. “I’m exhausted,” Wong told the Daily News by phone on Wednesday. “I’m physically, mentally and even sometimes spiritually exhausted. I have given everything I’ve got for the city for the past 10 months and then some, and it has taken a toll on my health and it is to the point where I have to take a step back.”