#!/bin/sh

if [ $# -ne 1 ] && [ $# -ne 2 ]; then
  >&2 printf 'usage: %s url [output-directory]\n' "${0##*/}"
  exit 1
fi

url="${1%/}/"
if [ $# -eq 1 ]; then
  dir=$(mktemp -d)
else
  dir="$2"
fi

curl -L -o "${dir}/#1" "$(
  curl -LSs "${url}" \
  | sed '
    s@^.*href="\([0-9]\+-[a-zA-Z]\+\.txt\(\.gz\)\?\)\">.*$@\1@
    t
    d
  ' \
  | tr '\n' ',' \
  | sed '
    s@^\(.*\),$@'"${url}"'{\1}\n@
  '
)"

>&2 printf 'Data resides in %s\n' "${dir}"