#!/bin/sh

# Generate a CSL bibliography entry from a DOI or ISBN

if test "${1#*10.}" != "$1"; then
  # DOI
  curl -sLH 'Accept: application/x-bibtex' "https://doi.org/$1" \
  | pandoc -f bibtex -t markdown -s
else
  # ISBN
  oclc=$(curl -sI "https://www.worldcat.org/isbn/$1" \
       | sed -nE '/^Location:/ {s@.*oclc/([0-9]+).*@\1@p; q}')

  curl -s "https://openlibrary.org/api/volumes/brief/isbn/$1.json" \
  | jq --arg oclc "$oclc" '
    def splitname:
      split(" ") | {family: .[-1], given: .[0:-1] | map (.[0:1] + ".")| join(" ")};
    [.records | .[]] | .[0] as $reply
    | ($reply.data + $reply.details) as $data
    | [{author: $data.authors | map(.name | splitname),
        isbn: $data.identifiers.isbn_10[0],
        edition: $data.details | (.edition_name // "1") | split(" ") | .[0] | sub("[a-z]+"; ""),
        issued: $data.publish_date,
        publisher: $data.details.publishers[0],
        "publisher-place": $data.details | (.publish_places[0] // "Nowhere"),
        type: "book",
        title: $data.title,
        url: ("https://www.worldcat.org/oclc/" + $oclc)}]' \
  | pandoc -f csljson -t markdown -s
fi | sed '
# delete start of header
1,3d
# insert the reference id
/^- / {i - id: CHANGE_ME
s/- /  /
}
# unquote the url
/url:/ s/"//g
# delete end of header
/^---/d
$d'