#!/bin/sh -u
#
# Stash strings for later.
# Adapted from noteurl.
#	- Cameron Simpson <cs@zip.com.au> 15nov1996
#
# Streamlined the logic.	- cameron, 16feb1998
# Fix race condition on tag existence. - cameron, 14sep1998
#

: ${TMPDIR:=/tmp}
: ${LOGDIR:=$HOME/var/log}

cmd=`basename "$0"`
usage="Usage: $cmd [-t tag] notefile [strings...]
	-d date	Make tag line for specified date.
	-p pfx	Addenda prefix (default: a tab).
	-s sfx	Addenda suffix.
	-t tag	Tag line.
	-H hhmm	hh:mm string."

notedir=$LOGDIR/notes
notefile=
when=now
tag=
tagfmt='%a %b %d %Y'
hhmm=
pfx='	'
sfx=
locked=

badopts=

while [ $# -gt 0 ]
do
    case $1 in
	-d)	when=$2; shift ;;
	-p)	pfx=$2; shift ;;
	-s)	sfx=$2; shift ;;
	-t)	tag=$2; shift ;;
	-H)	hhmm=$2; shift ;;
	-l)	locked=1 ;;
	--)	shift; break ;;
	-?*)	echo "$0: unrecognised option: $1" >&2
		badopts=1
		;;
	*)	break ;;
    esac
    shift
done

[ $# = 0 ] || { notefile=$1; shift; }

[ -n "$notefile" ] || { echo "$0: missing notefile" >&2; badopts=1; }

[ $badopts ] && { echo "$usage" >&2; exit 2; }

# clean up notefile spec
case $notefile in
    /*)	;;
    *)	notefile=$notedir/$notefile ;;
esac

[ -f "$notefile" ] || { echo "$0: missing notefile: $notefile" >&2
			exit 1
		      }

# default tag if none supplied

[ -n "$tag" ] || tag=`date -d "$when" "+$tagfmt"` || exit 1
[ -n "$hhmm" ] || hhmm=`date -d "$when" '+%H:%M'` || exit 1

# loopback - lock the file and rerun
[ $locked ] \
  || exec lock "$notefile" "$0" -l -p "$pfx" -s "$sfx" -t "$tag" -H "$hhmm" -- "$notefile" ${1+"$@"}

# collect lines to add
tmpf=$TMPDIR/$cmd.$$
trap 'rm -f "$tmpf"' 0
trap 'rm -f "$tmpf"; exit 1' 1 2 13 15
if [ $# = 0 ]
then cat
else for line
     do printf "%s\\n" "$line"
     done
fi \
| sed -e "s^$hhmm " -e "s^$pfx" -e "s\$$sfx" >"$tmpf" || exit 1

[ -s "$tmpf" ] || exit 0	# nothing to add

# ensure the tagline exists
case "$tag" in
  */*)	tagptn=`sedstrs "s|/|\\\\\\\\/|g" "$tag"` ;;
  *)	tagptn=$tag ;;
esac
grep "^$tagptn" "$notefile" >/dev/null \
|| bsed -s "1i\
$tag" "$notefile" \
|| exit 1

## NB: no exec because the trap needs to run
##set -x
bsed -s "/^$tagptn/r $tmpf" "$notefile"