_ssh_hosts() {
  mapfile -t hosts < <(awk 'tolower($1) == "host" { print $2 }' ~/.ssh/config)
  mapfile -t COMPREPLY < <(compgen -W "${hosts[*]}" -- "${COMP_WORDS[COMP_CWORD]}")
  return 0
}

complete -o default -F _ssh_hosts ssh scp ssh-copy-id sftp

_make_targets() {
  local arg prev file targets

  if [[ -f makefile ]]; then
    file=makefile
  elif [[ -f Makefile ]]; then
    file=Makefile
  fi

  for arg in "${COMP_WORDS[@]}"; do
    if [[ $prev = -f ]]; then
      file=$arg
    elif [[ $arg = -f* ]]; then
      file=${arg#-f}
    fi

    prev=$arg
  done

  mapfile -t targets < <(
    awk '$1 ~ /:$/ && $1 !~ /^\./ { gsub(/:$/, "", $1); print $1 }' "$file"
  )

  mapfile -t COMPREPLY < <(
    compgen -W "${targets[*]}" -- "${COMP_WORDS[COMP_CWORD]}"
  )
}

complete -o default -F _make_targets make gmake