#!/bin/bash

echo "[ BTRFSwapper - Easy swapfile and swapiness management on btrfs fs ]"

if [ -z $1 ]; then
	echo "Usage: btrfswapper nG (example: btrfswapper 8G will create a 8GB swap file)"
	exit
fi

if [ -z $2]; then
	SWAPINESS_SET=60
else
	SWAPINESS_SET=$2
fi

sudo echo "Hey, we need to write on the top directory!"
cd /

if test -d "swapdir"; then
	cd swapdir
else
	sudo mkdir swapdir
	cd swapdir
fi

if test -f "swapfile"; then
	sudo truncate -s 0 swapfile
else
	sudo dd if=/dev/zero of=/swapdir/swapfile bs=1G count=1
	sudo truncate -s 0 swapfile
fi
sudo chattr +C swapfile
sudo fallocate -l $1 swapfile
sudo chmod 0600 swapfile
sudo mkswap swapfile
sudo swapon swapfile

echo "[ ok ] Done, your swapfile should be ok!"
echo "[ ... ] Setting swappiness...(temporarily. To make it persistant do it yourself)"
echo "[!] Look, you can make it persistant by editing /etc/sysctl.conf and locating vm.swappiness"
echo "[!] Is quite too dangerous for me."
echo "[*] Better safe than sorry"
sudo sysctl vm.swappiness=$SWAPINESS_SET
echo "[ ok ] swappiness for the current session is now $SWAPINESS_SET"