#!/bin/sh
# Usage:
# Meta/amlook <mbox (for single message from MUA) or
# Meta/amlook id1 id2... (from the command line)
# Meta/amlook --gc

MASTER=master

find_commit () {
	in= commits=

	if test -z "$commits"
	then
		# I know I know there should be "notes grep" command...
		commits=$(
			git grep -l -e "$1" notes/amlog |
			sed -e 's|^notes/amlog:||' -e 's|/||g'
		)
	fi

	if test -z "$commits"
	then
		commits=$(sed -ne "s|^\([0-9a-f]\{40\}\) $1|\1|p" .git/am.log)
	fi

	if test -z "$commits"
	then
		echo "Never applied"
		return
	fi

	echo "$commits"

	found=$(
		echo "$commits" |
		while read commit
		do
			git branch --with $commit
		done | sed -e 's|^..||' |
		sort -u |
		tr '\012' ' '
	)
	if test -z "$found"
	then
		echo "Not merged ($commits)"
		return
	fi
	case " $found " in
	*' maint '*) in=maint ;;
	*" $MASTER "*) in=$MASTER ;;
	*' next '*) in=next ;;
	esac
	if test -n "$in"
	then
		echo "Found in $in"
	else
		echo "Found in $found"
	fi
}

garbage_collect () {
	cutoff_days=${1-"180"} &&
	git notes --ref amlog list |
	sed -e 's/.* //' |
	xargs -n 1 git show -s --format="%ci %H" 2>/dev/null |
	perl -e '
		my @time = localtime(time() - $ARGV[0] * 24 * 3600);
		my $cutoff = sprintf("%04d-%02d-%02d 00:00:00",
				$time[5]+1900, $time[4]+1, $time[3]);
		while (<STDIN>) {
			if ($_ le $cutoff) {
				s/.* //;
				print;
			}
		}
	' "$cutoff_days" >..gcinput

: <<\INVALID
	: (
		GIT_INDEX_FILE=/tmp/amlook.$$.tmp &&
		export GIT_INDEX_FILE &&
		rm -f "$GIT_INDEX_FILE" &&
		git read-tree refs/notes/amlog &&
		xargs git rm -f &&
		T=$(git write-tree) &&
		C=$(echo Prune amlog | git commit-tree $T -p refs/notes/amlog) &&
		git update-ref -m "Prune amlog" refs/notes/amlog $C
	)
INVALID
}

if test $# = 0
then
	msg=$(sed -ne '
		/^[ 	]/{
			# Append continuation line
			H
			x
			s/\n//
			x
			n
		}
		# Hold this new line, and look at what is in the hold space
		x
		# Is it the Message-ID line?  If so, spit out and finish.
		/^[Mm][Ee][Ss][Ss][Aa][Gg][Ee]-[Ii][Dd]:[ 	]*/{
			s///p
			q
		}
		# Otherwise, check if this new line is empty
		x
		# Is it?  Then we are done with the header
		/^$/b end
		# Otherwise we need to hold onto this header line
		x
		# And start the next cycle
		b
	: end
		q
	') &&
	find_commit "$msg"
elif test "$1" = "--gc"
then
	shift
	garbage_collect "$@"
elif test "$1" == "--squash"
then
	L=notes/amlog &&
	git notes --ref=$L prune &&
	C=$(echo amlog | git commit-tree refs/$L^{tree}) &&
	git update-ref refs/$L $C
else
	for msg
	do
		find_commit "$msg"
	done
fi