post_install() {
  groupadd -f flutterusers
  chgrp -R flutterusers /opt/flutter
  chmod -R g+w /opt/flutter
  tput setaf 0 2>/dev/null
  if [[ "$?" == "0" ]]; then
    tput sgr0
    printf "$(tput setaf 4)Flutter was installed on $(tput setaf 2)/opt/flutter$(tput sgr0)\n"
    printf "$(tput setaf 4)$(tput sgr0)\n"
    printf "$(tput setaf 4)In case you encounter problems using Flutter as regular user, add your user into the group flutterusers:$(tput sgr0)\n"
    printf "$(tput setaf 2)gpasswd -a \${USER} flutterusers$(tput sgr0)\n"
    printf "$(tput setaf 4)$(tput sgr0)\n"
    printf "$(tput setaf 4)Re-login your terminal in to the group flutterusers:$(tput sgr0)\n"
    printf "$(tput setaf 2)newgrp flutterusers$(tput sgr0)\n"
    printf "$(tput setaf 4)$(tput sgr0)\n"
    printf "$(tput setaf 4)Run the following command to see if there are any dependencies you need to install to complete the setup (for verbose output, add the -v flag):$(tput sgr0)\n"
    printf "$(tput setaf 2)flutter doctor$(tput sgr0)\n"
  else
    printf "Flutter was installed on /opt/flutter\n"
    printf "\n"
    printf "In case you encounter problems using Flutter as regular user, add your user into the group flutterusers:\n"
    printf "gpasswd -a \${USER} flutterusers\n"
    printf "\n"
    printf "Re-login your terminal in to the group flutterusers:\n"
    printf "newgrp flutterusers\n"
    printf "\n"
    printf "Run the following command to see if there are any dependencies you need to install to complete the setup (for verbose output, add the -v flag):\n"
    printf "flutter doctor\n"
  fi
}

post_upgrade() {
  post_install
}

post_remove() {
  groupdel flutterusers
  printf "$(tput setaf 4)If you had added/modified files or permissions in folder /opt/flutter is possible you need to delete it manually.$(tput sgr0)\n"
  printf "$(tput setaf 2)rm -rf /opt/flutter$(tput sgr0)\n"
}