#!/bin/bash

SWAPPATH=~/
SWAPNAME="swapfile"
TOTALRAM=$(free -m | gawk  '/Mem:/{print $2}')
VERSION="0.1.0"
BUILDDATE="2018-06-05"


function autoSwap(){
        echo -e "\nTotal Physical RAM is: ${TOTALRAM} MB\n"
        echo -e "\nCreating a ${TOTALRAM} MB file in:${SWAPPATH}..\n"
        echo -e "Enter to Accept | Ctrl+c to cancel\n"
        read

        echo -e "\nCreating file in ${SWAPPATH}...\n"
        sudo fallocate -l ${TOTALRAM}M ${SWAPPATH}${SWAPNAME}
        ls -lh ${SWAPPATH}${SWAPNAME}

        sleep 1

        echo -e "\nSetting permission of ${SWAPPATH}${SWAPNAME} to 600...\n"
        sudo chmod 600 ${SWAPPATH}${SWAPNAME}
        ls -lh ${SWAPPATH}${SWAPNAME}

        sleep 1
        
        echo -e -n "\nDo you want to mark ${SWAPPATH}${SWAPNAME} as swap?(Y/n): "
        read markswap

        if [ "${markswap}" = "n" ];then
            exit 0
        fi

        echo -e "\nMarking ${SWAPPATH}${SWAPNAME} as swap...\n\n"
        sudo mkswap ${SWAPPATH}${SWAPNAME}

        echo -e -n "\nDo you want to add swapfile to fstab?(Y/n): "
        read addfstab

        if [ "${addfstab}" = "n" ];then
            exit 0
        fi

        echo -e "\nCreating backup of /etc/fstab ...\n"
        sudo cp /etc/fstab /etc/fstab.bak

        echo -e "Adding ${SWAPPATH}${SWAPNAME} to /etc/fstab ..\n"
        echo "${SWAPPATH}${SWAPNAME} none swap sw 0 0" | sudo tee -a /etc/fstab
}


function help(){
    echo -e "\nUsage: $0 [-a] [--auto]\n\n"
    echo -e "-a | --auto        Automatically create and size swapfile based on physical memory\n"
}

function version(){
    echo -e "Version ${VERSION}, built: ${BUILDDATE}\n"
}

case "${1}" in

    -a|--auto)
        autoSwap
    ;;

    -v|version|--version)
        version
    ;;

    *)
        help
    ;;
esac