#!/bin/sh
# bib-add - insert bibtex entries from stdin into a database file
#
# usage: bib-add [-f] db.bib < entry
#   -f  replace existing entries with the same key

usage() {
  printf 'usage: bib-add [-f] db.bib < entry\n' >&2
  exit 2
}

if [ -n "$BIBUTILS_LIB" ]; then
  LIB=$BIBUTILS_LIB
elif [ -d "$(dirname "$0")/lib" ]; then
  LIB=$(dirname "$0")/lib
else
  LIB=/usr/local/share/bibutils
fi

force=0
while getopts f opt; do
  case $opt in
    f) force=1 ;;
    *) usage ;;
  esac
done
shift $((OPTIND - 1))
[ $# -eq 1 ] || usage
db=$1

tmp=$(mktemp) && tmpkeys=$(mktemp) && tmpdb=$(mktemp) || exit 1
trap 'rm -f "$tmp" "$tmpkeys" "$tmpdb"' EXIT INT TERM

# canonicalize the incoming entries
awk -f "$LIB/bib-parse.awk" -f "$LIB/bib-canon.awk" -f "$LIB/bib-select.awk" \
    -v keys= -v invert=1 > "$tmp"

if [ ! -s "$tmp" ]; then
  printf 'bib-add: no entries on stdin\n' >&2
  exit 1
fi

awk -f "$LIB/bib-parse.awk" -f "$LIB/bib-lskeys.awk" "$tmp" > "$tmpkeys"

if [ -f "$db" ]; then
  dups=$(awk -f "$LIB/bib-parse.awk" -f "$LIB/bib-lskeys.awk" "$db" \
      | grep -Fxf "$tmpkeys") || dups=
  if [ -n "$dups" ]; then
    if [ "$force" -eq 1 ]; then
      # rewrite the database without the entries being replaced
      keys=$(printf '%s\n' "$dups" | paste -sd, -)
      awk -f "$LIB/bib-parse.awk" -f "$LIB/bib-canon.awk" \
          -f "$LIB/bib-select.awk" -v keys="$keys" -v invert=1 \
          "$db" > "$tmpdb" || exit 1
      cp "$tmpdb" "$db"
    else
      printf 'bib-add: duplicate keys in %s:\n' "$db" >&2
      printf '%s\n' "$dups" >&2
      exit 1
    fi
  fi
fi

{
  [ -s "$db" ] && echo ""
  cat "$tmp"
} >> "$db"