#!/bin/bash
# give one DE (Desktop environment) to remove and another to keep.
# send any bugs to ej_112@hotmail.com or /msg EriC^^ on freenode

main()
{
if [ $EUID -ne 0 ]; then
echo "Run the script as root. sudo $0"
exit
fi

if [ -z "$1" ]; then
usage
exit
fi

if [ "$1" = "-i" ]; then
interactive
elif [ "$1" = "-V" ] || [ "$1" = "--version" ]; then
version
exit
else
package="$1"
packagekeep="$2"
if [ -n "$3" ] || [ ! -n "$2" ]; then
usage
exit
fi
fi
echo "*** Removing package $package and keeping $packagekeep"
echo "*** USE THIS PROGRAM AT YOUR OWN RISK."
echo -n "*** Continue? [Y/n]: "
read cont
cont=$(echo $cont | tr '[:upper:]' '[:lower:]')
if [ "$cont" != "y" ] && [ "$cont" != "yes" ]; then
exit
fi


if [ "$(apt-cache policy $package | awk '/Installed/ {print$2}')" = "(none)" ]; then
echo -n "$package seems to be removed.. package needed to get the list of dependencies, reinstall? [y/n]: "
cont=""
read cont
cont=$(echo $cont | tr '[:upper:]' '[:lower:]')
if [ "$cont" != "y" ] && [ "$cont" != "yes" ]; then
exit
fi

apt-get install --reinstall $package
if [ "$(apt-cache policy $package | awk '/Installed/ {print$2}')" = "(none)" ]; then
echo "*** Failed to install $package.. exiting"
exit
fi
fi

if [ "$(apt-cache policy $packagekeep | awk '/Installed/ {print$2}')" = "(none)" ]; then
echo "$packagekeep seems to be removed.. are you sure about the name? Exiting.."
exit
fi

echo "*** Checking if debfoster and apt-rdepends are installed.."

if [ "$(dpkg -l | awk '$2 ~ /^debfoster$/ {print$1}')" != "ii" ]; then
echo "debfoster is not installed.. installing"
apt-get -qq install debfoster
if [ "$(dpkg -l | awk '$2 ~ /^debfoster$/ {print$1}')" != "ii" ]; then
echo "*** Failed to install debfoster.. exiting"
exit
fi

else 
echo "*** debfoster [OK]"
fi

if [ "$(dpkg -l | awk '$2 ~ /^apt-rdepends$/ {print$1}')" != "ii" ]; then
echo "*** apt-rdepends is not installed.. installing"
apt-get -qq install apt-rdepends
if [ "$(dpkg -l | awk '$2 ~ /^apt-rdepends$/ {print$1}')" != "ii" ]; then
echo "*** Failed to install apt-rdepends.. exiting"
exit
fi

else 
echo "*** apt-rdepends [OK]"
fi


echo "*** Getting list of dependencies"
removedepsdeb=$(debfoster -d $package | tail -n +2)
removedepsapt=$(apt-rdepends $package 2> /dev/null | awk '/Depends/ {print $2}' | sort -u)

keepdepsdeb=$(debfoster -d $packagekeep | tail -n +2)
keepdepsapt=$(apt-rdepends $packagekeep 2> /dev/null | awk '/Depends/ {print $2}' | sort -u)

echo "*** Got list of dependencies"
echo "*** Getting all list of packages found in $package that $packagekeep doesn't depend on"
remove=""

for i in $removedepsapt; do
if ! echo $keepdepsapt | grep -q $i; then
remove="$remove $i"
fi
done

i=""
for i in $remove; do
if ! echo $keepdepsdeb | grep -q $i; then
toremove="$toremove $i"
fi
done

echo "Packages to remove $toremove"
echo "Save list to file for editing? continue removing? exit?"
echo -n "[Save/Continue removing/Exit]: "

cont=""
read cont
cont=$(echo $cont | tr '[:upper:]' '[:lower:]')

if [ "$cont" == "e" ] || [ "$cont" == "exit" ]; then
exit
fi

if [ "$cont" == "s" ] || [ "$cont" == "save" ]; then
echo -n "Enter name to save list: "
read -r save; if [[ "${save:0:1}" = "~" ]]; then if [[ "${save:1:1}" = "/" ]]; then save="${save/\~/$HOME}"; else save="${save/\~/\/home/}"; fi; fi
if [ ! -f "$save" ]; then
echo "$toremove" > "$save"
echo "Packages saved in $save"
echo "Use sudo xargs -a $save apt-get -y purge"
echo "To remove them"
exit
else
echo "File already exists, Exiting.."
exit
fi
fi

if [ "$cont" != "c" ] && [ "$cont" != "continue" ]; then
echo "No option selected"
exit
fi

apt-get purge $toremove
echo -n "*** Reinstall packages of the DE that was selected to keep? (Optional) [Y/n]:"
cont=""
read cont
cont=$(echo $cont | tr '[:upper:]' '[:lower:]')
if [ "$cont" != "y" ] && [ "$cont" != "yes" ]; then
exit
fi

echo "[1] Reinstall the meta-package."
echo "[2] Reinstall the first few dependencies of the meta-package (takes a little longer)"
echo "[3] Reinstall all the dependencies of the meta-package (takes a long time)"
echo -n "Enter a number: "
cont=""
read cont
if [ "$cont" = "1" ]; then
apt-get -y install --reinstall $packagekeep
exit

elif [ "$cont" = "2" ]; then
apt-cache depends $packagekeep | awk '/Depends/ {print $2}' | xargs apt-get -y install --reinstall
exit

elif [ "$cont" = "3" ]; then
apt-get -y install --reinstall $keepdepsapt
exit
fi
echo "No option selected"
exit

}

sel()
{
echo "[1] ubuntu/unity"
echo "[2] lubuntu"
echo "[3] xubuntu"
echo "[4] ubuntu gnome"
echo "[5] ubuntu studio"
echo "[6] kubuntu"
echo "[7] custom"
echo -n "Enter a number 1-7: " 
read denum

case "$denum" in
		1) packagesel=ubuntu-desktop;;
		2) packagesel=lubuntu-desktop;;
		3) packagesel=xubuntu-desktop;; 
		4) packagesel=ubuntu-gnome-desktop;;
		5) packagesel=ubuntustudio-desktop;;
		6) packagesel=kubuntu-desktop;;
		7) echo -n "Enter the name of the package: "
		   read packagesel ;;
		*) echo "Please enter a number between 1 and 7"; exit ;;
esac
if [ "$1" = "remove" ]; then
bla=remove
else
bla=keep
fi
echo "Selected package to $bla is $packagesel"
echo -n "Continue? [Y/n]: "
read cont
cont=$(echo $cont | tr '[:upper:]' '[:lower:]')
if [ "$cont" != "y" ] && [ "$cont" != "yes" ]; then
exit
fi

if [ "$1" = "remove" ]; then
package=$packagesel
else
packagekeep=$packagesel
fi
}

interactive()
{
echo "Which DE would you like to remove?"
sel remove
echo "Which DE would you like to keep?"
sel keep
}

usage()
{
echo "Type a DE (Desktop Environment) package to remove and a DE to keep" 
echo
echo "sudo $0 <de to remove> <de to keep>"
echo "e.g sudo $0 lubuntu-desktop ubuntu-desktop"
echo
echo "or run sudo $0 -i for an interactive mode"
}

version()
{
echo "remove-de"
echo "send bugs to ej_112@hotmail.com or /msg EriC^^ on freenode"
}
main "$@"