[ "${taggery_name}" -a "${taggery_fmturl}" -a "${taggery_image_url_filter}" -a "${taggery_image_tags_filter}" ] || {
  cat <<EOF
Taggery v0.1
Copyright - http://wiki.cyberleo.net/wiki/CyberLeo/COPYRIGHT?version=4

Set the following variables before sourcing this library:

 taggery_base              - The base directory where the taggery database
                             resides. This should contain the directories
                             md5/ tag/ pool/
 taggery_libs              - The base directory where the code resides.

The following should be defined by the profile:

 taggery_name              - A string token to use when formatting things
 taggery_fmturl            - A printf-compatible format string that will
                             transform an ID into the URL of a 'view' page.
 taggery_image_url_filter  - A program or function that takes a webpage on
                             stdin and provides on stdout the URL to the raw
                             image to be downloaded.
 taggery_image_tags_filter - A program or function that takes a webpage on
                             stdin and provides on stdout a list of newline-
                             delimited tags.
 taggery_image_referer     - A program or function that takes an id and
                             returns the referer URL for that id.

Examples:
 Format URL:
  taggery_fmturl="http://e621.net/post/show/%s"
  taggery_fmturl="http://gelbooru.com/index.php?page=post&s=view&id=%s"

 Filters:
  e621_image_url_filter() { sed -e '...'; }
  taggery_image_url_filter="e621_image_url_filter"
EOF
  kill $$
  exit 1
}

taggery_cleanup() {
  local cleanup="$(kvs_get "${taggery_name}" cleanup)"
  if [ "${cleanup}" ]
  then
    local id
    for id in ${cleanup}
    do
      taggery_free_page "${id}"
    done
  fi
  kvs_unset "${taggery_name}" cleanup
}
[ "${DEBUG}" ] || trap "taggery_cleanup" EXIT HUP INT TERM KILL

taggery_register_cleanup() {
  [ "${1}" ] || return 1
  local id="${1}"
  kvs_set "${taggery_name}" cleanup "$(kvs_get "${taggery_name}" cleanup) ${id}"
}

taggery_init_page() {
  [ "${1}" ] || return 1
  local id="${1}"
  kvs_set "${taggery_name}/${id}" tmp "$(mktemp "${taggery_temp}/.taggery_${id}.XXXXXXXX")"
  kvs_set "${taggery_name}/${id}" url "$(printf "${taggery_fmturl}" "${id}")"
  taggery_register_cleanup "${id}"
}

taggery_free_page() {
  [ "${1}" ] || return 1
  local id="${1}"
  local tmp="$(kvs_get "${taggery_name}/${id}" tmp)"
  [ -f "${tmp}" -a "${tmp%%_*}" = "${taggery_temp}/.taggery" ] && rm -f "${tmp}"
  kvs_unset_all "${taggery_name}/${id}"
}

taggery_fetch_page() {
  [ "${1}" ] || return 1
  local id="${1}"
  kvs_has_id "${taggery_name}/${id}" || taggery_init_page "${id}"
  local url="$(kvs_get "${taggery_name}/${id}" url)"
  local tmp="$(kvs_get "${taggery_name}/${id}" tmp)"
  wget ${taggery_user_agent:+--user-agent="${taggery_user_agent}"} -qO "${tmp}" "${url}"
}

taggery_page() {
  [ "${1}" ] || return 1
  local id="${1}"
  kvs_has_id "${taggery_name}/${id}" || taggery_init_page "${id}"
  local tmp="$(kvs_get "${taggery_name}/${id}" tmp)"
  [ -s "${tmp}" ] || taggery_fetch_page "${id}"
  cat "${tmp}"
}

taggery_id() {
  [ "${1}" ] || return 1
  local url="${1}"
  echo "${url}" | "${taggery_id_filter}"
}

taggery_image_name() {
  [ "${1}" ] || return 1
  local id="${1}"
  local url="$(taggery_image_url "${id}")"
  if [ "${taggery_image_name_filter}" ]
  then
    "${taggery_image_name_filter}" "${id}" "${url}"
  else
    name="$(basename "${url}")"
    name="${name%%\?*}"
    echo "${name}"
  fi
}

taggery_image_url() {
  [ "${1}" ] || return 1
  local id="${1}"
  taggery_page "${id}" | "${taggery_image_url_filter}"
}

taggery_image_referer() {
  [ "${1}" ] || return 1
  local id="${1}"
  [ "${taggery_image_referer}" ] || return 0
  "${taggery_image_referer}" "${id}"
}

taggery_fetch_image() {
  [ "${1}" ] || return 1
  local id="${1}"
  name="$(taggery_image_name "${id}")"
  file="$(taggery_image_url "${id}")"
  referer="$(taggery_image_referer "${id}")"
  wget ${taggery_user_agent:+--user-agent="${taggery_user_agent}"} ${referer:+--referer="${referer}"} -O "${taggery_base}/md5/${name}" "${file}"
}

taggery_image_tags() {
  [ "${1}" ] || return 1
  local id="${1}"
  echo "${taggery_name}"
  taggery_page "${id}" | "${taggery_image_tags_filter}"
}

taggery_sanitize_tag() {
  [ "${1}" ] || return 1
  local tag="${1}"
  echo "${tag}" | sed -e 's/\//%47/g; s/[\]/\\&/g'
}

taggery_link_tags() {
  [ "${1}" ] || return 1
  local id="${1}"
  taggery_image_tags "${id}" | while read tag
  do
    [ "${tag}" ] || continue
    echo "${tag}"
    tag="$(taggery_sanitize_tag "${tag}")"
    mkdir -p "${taggery_base}/tag/${tag}"
    ln -sf "../../md5/${name}" "${taggery_base}/tag/${tag}/"
  done
}

: ${taggery_temp:=${taggery_base}/tmp}

mkdir -p "${taggery_temp}" "${taggery_base}/md5" "${taggery_base}/tag" "${taggery_base}/pool"
TMPDIR="${taggery_temp}"
kvs="${taggery_temp}/taggery.kvs"
. "${taggery_libs}/kvs.sh"