#!/bin/sh

set -e

pid_file="/tmp/${0##*/}.pid"
if [ -f "${pid_file}" ] \
&& kill -0 "$(cat "${pid_file}")" >/dev/null 2>&1; then
  >&2 printf 'another %s is running as %s\n' "${0##*/}" "$(cat "${pid_file}")"
  exit
fi

echo $$ \
> "${pid_file}"
trap 'rm "${pid_file}"' EXIT

if ! tty -s; then
  sleep $((${RANDOM} % 3600))
fi

cache_dir=$(readlink -e "$(dirname "$0")/../httpdocs")

mkdir -p \
  "${cache_dir}/md5sum" \
  "${cache_dir}/sha1sum" \
  "${cache_dir}/sha256sum" \
  "${cache_dir}/sha512sum"

grep '^[^#]' "$(dirname "$0")/downloads.list" | \
  while read -r url urlDir; do
    if [ -n "${urlDir}" ] || \
      echo "${url}" | \
        grep -q '\*[^/]*$'; then
      if [ -z "${urlDir}" ]; then
        urlDir=$(
          printf '%s\n' "${url}" | \
            sed 's|/[^/]*$|/|'
        )
        urlPrefix="${urlDir}"
        urlFile="${url##*/}"
        spacer='/'
      else
        urlPrefix=$(
          printf '%s\n' "${url}" | \
            sed '
              s,\([^/]/\)[^/].*$,\1,
            '
        )
        urlFile="/${url#*//*/}"
        spacer=''
      fi
      urlFile=$(
        printf '%s\n' "${urlFile}" | \
          sed '
            s|\.|\\.|g
            s|*|.*|g
          '
      )
      wget --no-check-certificate -O - "${urlDir}" 2> /dev/null | \
        tr '"<>'"${spacer}" '\n' | \
        grep '\(^\|/\)'"${urlFile}\$" | \
        sort -u | \
        xargs -r printf "${urlPrefix}%s\n"
    else
      printf '%s\n' "${url}"
    fi
  done | \
  while read -r url; do
    if ! wget --no-check-certificate -O "${cache_dir}/tmp" "${url}" 2> /dev/null; then
      continue
    fi
    sha512=$(
      sha512sum "${cache_dir}/tmp" | \
        cut -d' ' -f1
    )
    sha256=$(
      sha256sum "${cache_dir}/tmp" | \
        cut -d' ' -f1
    )
    sha1=$(
      sha1sum "${cache_dir}/tmp" | \
        cut -d' ' -f1
    )
    md5=$(
      md5sum "${cache_dir}/tmp" | \
        cut -d' ' -f1
    )
    if [ ! -f "${cache_dir}/sha512sum/${sha512}" ]; then
      mv "${cache_dir}/tmp" "${cache_dir}/sha512sum/${sha512}"
    else
      rm "${cache_dir}/tmp"
    fi
    if [ ! -f "${cache_dir}/sha256sum/${sha256}" ]; then
      ln "${cache_dir}/sha512sum/${sha512}" "${cache_dir}/sha256sum/${sha256}"
    fi
    if [ ! -f "${cache_dir}/sha1sum/${sha1}" ]; then
      ln "${cache_dir}/sha512sum/${sha512}" "${cache_dir}/sha1sum/${sha1}"
    fi
    if [ ! -f "${cache_dir}/sha1sum/${md5}" ]; then
      ln "${cache_dir}/sha512sum/${sha512}" "${cache_dir}/sha1sum/${md5}"
    fi
  done