Villain is a maniac I have 30 hands on and who does everything too much. Cold calls too much preflop, raises too much, 3bets too much, bets too much on all streets and calls too much. Stats like 50/35/3.

Preflop, standard. His range is likely heavy in weak hands since he didn't raise preflop.

Flop he can have hit in many ways - straight, pair, pair with draw, two pair. However he'll have more missed than hit combos, especially as I'm blocking two of the sevens. I bet to get value and price out draws. He's maniac enough to call sometimes when he's missed the flop (floater)

Turn I get that sinking feeling. Flush is now possible. As means we can rule out AsKs type hands, but since we're looking at the weak part of his range we can probably argue any Asxs hand would have been raised preflop. But due to his looseness any two spades can be argued to be in his range. I bet slightly smaller on the turn so I can represent either the one-card flush draw or a protection bet from an ace.

He is aggro, so I would not be surprised if he at this point raises his nut hands - mainly the flushes. I also don't think he takes this line with sets so often. With the call I'd say his most likely hands are two pair, pair+draw or random crap because he's a maniac.

River, I'm really torn on. I think he has crap and bluffs enough without a spade that I can't fold it if I check to him and he shoves ($20 into $18). At the same time he has a spade often enough that I hate calling off my stack. I hate shoving, because I'm only called when I'm beat.

Any suggestions?

PokerStars No-Limit Hold'em, $0.25 BB (5 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

saw flop

MP ($27.90)
Button ($47.60)
SB ($25.70)
Hero (BB) ($50.15)
UTG ($29.50)

Preflop: Hero is BB with 7, 7
UTG calls $0.25, 2 folds, SB calls $0.15, Hero bets $1.50, UTG calls $1.25, 1 fold

Flop: ($3.25) 8, 6, 7 (2 players)
Hero bets $2.50, UTG calls $2.50

Turn: ($8.25) A (2 players)
Hero bets $5, UTG calls $5

River: ($18.25) 2 (2 players)
Hero ?