He was wielding a patu and a spear, the court heard.
"You're a nark, you're dead. It's all over for you," Smith told the man.
The next day he followed through on his threat of violence.
Smith knocked on the victim's door, walked in, then delivered a flurry of punches which knocked the man to the ground.
He aimed kicks at the man's head and body and told him to pack his bags.
The victim asked him why.
"It doesn't ... matter, you're an idiot," Smith replied.
When the man got up, the defendant continued to punch him in the head as hard as he could.
Even fleeing outside did not stop the attack.
Smith punched the man one more time and threw his phone on to the ground.
De Jager said his client was "self-medicating" at the time.
"He took himself off what the doctor prescribed him and put himself on meth," Judge Michael Turner clarified.
Three months later, Smith's wayward behaviour continued.
He slashed two tyres of a vehicle parked in Dowling St and could not be interviewed by police because of his aggressive demeanour.
Judge Turner noted Smith had a history of violence, particularly against women, but his life appeared to be back on track.
"By the absolute narrowest of margins", the defendant avoided a stay behind bars.
The judge imposed 300 hours' community work, 18 months' intensive supervision and $354 reparation.
Smith was unable to serve an electronically-monitored sentence because he lived in a large boarding house.
"If there's a take-home message today it's this: you either change your ways or you're going to prison. It's as simple as that," Judge Turner said.