#!/usr/bin/env bash

set -ex

script_path=$(dirname "$(realpath "$0")")

OS_REQUIREMENTS_FILENAME="$script_path/requirements.apt"

# Handle call with wrong command
function wrong_command() {
  echo "${0##*/} - unknown command: '${1}'"
  usage_message
}

# Print help / script usage
function usage_message() {
  echo "usage: ./${0##*/} <command>"
  echo "available commands are:"
  echo -e "\tlist\t\tPrint a list of all packages defined on ${OS_REQUIREMENTS_FILENAME} file"
  echo -e "\thelp\t\tPrint this help"
  echo -e "\n\tCommands that require superuser permission:"
  echo -e "\tinstall\t\tInstall packages defined on ${OS_REQUIREMENTS_FILENAME} file. Note: This\n\t\t\t   does not upgrade the packages already installed for new\n\t\t\t   versions, even if new version is available in the repository."
  echo -e "\tupgrade\t\tSame that install, but upgrade the already installed packages,\n\t\t\t   if new version is available."

}

# Read the requirements.apt file, and remove comments and blank lines
function list_packages() {
  grep -v "#" "${OS_REQUIREMENTS_FILENAME}" | grep -v "^$"
}

function install() {
  list_packages | xargs apt-get --no-upgrade install -y
}

function upgrade() {
  list_packages | xargs apt-get install -y
}

function install_or_upgrade() {
  P=${1}
  PARAN=${P:-"install"}

  if [[ $EUID -ne 0 ]]; then
    echo -e "\nYou must run this with root privilege" 2>&1
    echo -e "Please do:\n" 2>&1
    echo "sudo ./${0##*/} $PARAN" 2>&1
    echo -e "\n" 2>&1

    exit 1
  else

    apt-get update

    # Install the basic compilation dependencies and other required libraries of this project
    if [ "$PARAN" == "install" ]; then
      install
    else
      upgrade
    fi

    # cleaning downloaded packages from apt-get cache
    apt-get clean

    exit 0
  fi

}

# Handle command argument
case "$1" in
  install) install_or_upgrade ;;
  upgrade) install_or_upgrade "upgrade" ;;
  list) list_packages ;;
  help) usage_message ;;
  *) wrong_command "$1" ;;
esac