-- Player interactions; survival state remains owned by the caller.
return function(hearth)
	local function eat(amounts, replacement)
		return function(stack, player)
			if not player or not player:is_player() then return stack end
			local state = hearth.players[player:get_player_name()]
			if not state then return stack end
			local needed = false
			for key, value in pairs(amounts) do
				if type(state[key]) == "number" and state[key] < 100 and value > 0 then
					needed = true
				end
			end
			if not needed then return stack end
			for key, value in pairs(amounts) do
				if type(state[key]) == "number" then
					state[key] = math.max(0, math.min(100, state[key] + value))
				end
			end
			if replacement then stack:replace(replacement) else stack:take_item() end
			return stack
		end
	end

	return {eat = eat}
end