The plot is only superficially similar. It's like Hogfather, but without Death providing both comic relief and philosophy.
The title is definitely reminiscent of
Jake and the Fatman.
As for the idea of Santa having guns ... I've seen it at least twice before:
Dan Aykroyd dressing up like Santa in the movie "Trading Places" (classic!), and "Weird Al" Yankovic's song,
The Night Santa Went Crazy (now animated with lego!
).
***WARNING: Song not safe for work or kids. This is the "extra gory" version, in which Santa
In the "clean" version, Santa is just arrested.***
TBH, Mel Gibson hasn't made a decent film since the mid-90s, IMNSHO. But then, I never forgot that horrible anti-Semitic rant of his while he was arrested for DUI (back in 2006).
After that, all his movies basically looked like increasingly cheap copies of the "Lethal Weapon" movies - cheap and nasty - which is a shame.