addHook("PreThinkFrame", function()
	for player in players.iterate()
		local mo = player.mo
		if not (mo and player.charability == CA_TWINSPIN and player.charability2 == CA2_MELEE) then 
			player.airswap = 0
		continue end
		
		//Initialize
		if player.airswap == nil then
			player.airswap = 0
		end
		
		local jump = player.cmd.buttons&BT_JUMP
		local spin = player.cmd.buttons&BT_USE
		local jumplast = player.pflags&PF_JUMPDOWN
		local spinlast = player.pflags&PF_USEDOWN
		local lastswap = player.airswap		
		local shieldtype = player.powers[pw_shield]&~(SH_PITY|SH_PINK|SH_STACK)
		
		//Convert spring/fall frames to jump frames
		if mo.state == S_PLAY_FALL or mo.state == S_PLAY_SPRING then
			player.pflags = ($|PF_JUMPED|PF_NOJUMPDAMAGE)
		end
		
		if P_IsObjectOnGround(mo) then
			player.airswap = 0
		end
		if player.pflags&PF_JUMPED
			//Holding jump key
			if (jumplast) and not(spin)
				player.airswap = 0
			end
			//Pressing a new key while in the air
			if (spin and not spinlast)
				or (jump and not jumplast)
				player.airswap = 1
			end
		end
		
		//Perform swap
		if player.airswap == 1 then
			if jump then
				player.cmd.buttons = $|BT_USE
			else
				player.cmd.buttons = $&~BT_USE
			end
			if spin then
				player.cmd.buttons = $|BT_JUMP
			else
				player.cmd.buttons = $&~BT_JUMP
			end
		end
		//Change history if this is our first swap
		if lastswap != player.airswap then
			player.pflags = $&~(PF_USEDOWN|PF_JUMPDOWN)
			if jumplast then
				player.pflags = $|PF_USEDOWN
			end
			if spinlast then
				player.pflags = $|PF_JUMPDOWN
			end
		end
		//Deny jump hammers
		if not(shieldtype)
		and not(jumplast)
		and (jump)
		and player.pflags&PF_JUMPED
			player.pflags = $|PF_USEDOWN
		end
	end
end)