#!/bin/sh

pebkac() {
  [ "${*}" ] && printf "%s\n\n" "${*}"
  cat <<EOF
Usage: fixskel [-c|-i|-r]

 -c    Check symlinks for sanity
 -i    Install symlinks
 -r    Remove symlinks

This script will adjust the bash-config symlinks in /usr/share/skel
so that new users will be set up automatically. This is a companion
script to 'fixusers', which will set up existing users.

This script will avoid tampering with files that it thinks are
manually added. Use -c to check, and verify the files manually
afterwards.

EOF
  exit "${#}"
}

files="bash_profile bashrc"

mine() {
  [ "${#}" -eq 0 ] && set - ${files}
  while [ "${1}" ]
  do
    file="${1}"
    skel="/usr/share/skel/dot.${file}"
    real="/usr/local/etc/bash-config/${file}"
    if [ ! -L "${skel}" ] || [ "$(realpath "$(readlink "${skel}")")" != "$(realpath "${real}")" ]
    then
      return 1
    fi
    shift
  done
  return 0
}

gone() {
  [ "${#}" -eq 0 ] && set - ${files}
  while [ "${1}" ]
  do
    file="${1}"
    skel="/usr/share/skel/dot.${file}"
    [ -f "${skel}" ] && return 1
    shift
  done
  return 0
}

check() {
  [ "${#}" -eq 0 ] && set - ${files}
  while [ "${1}" ]
  do
    file="${1}"
    if gone "${file}"
    then
      echo "File ${file} does not exist."
    else
      if mine "${file}"
      then
        echo "File ${file} is mine."
      else
        echo "File ${file} exists, but is not mine."
      fi
    fi
    shift
  done
}

install() {
  if mine
  then
    echo "Skel symlinks appear to be correct"
    return 0
  fi
  
  if ! gone
  then
    echo "Skel files (${files}) appear to exist, and are not mine"
    echo "Refusing to molest them"
    return 1
  fi
  
  for file in ${files}
  do
    skel="/usr/share/skel/dot.${file}"
    real="/usr/local/etc/bash-config/${file}"
    ln -s "${real}" "${skel}" || return $?
  done
  return 0
}

remove() {
  if gone
  then
    echo "Skel symlinks already removed"
    return 0
  fi
  
  if ! mine
  then
    echo "Skel files (${files}) appear to exist, and are not mine"
    echo "Refusing to molest them"
    return 1
  fi
  
  for file in ${files}
  do
    skel="/usr/share/skel/dot.${file}"
    rm -f "${skel}" || return $?
  done
  return 0
}

while getopts "cir" opt
do
  case "${opt}" in
  c)  check; exit $? ;;
  i)  install; exit $? ;;
  r)  remove; exit $? ;;
  [?]) pebkac "Unrecognized option ${OPTARG}" ;;
  esac
done

pebkac