#!/bin/sh
#
# Copyright (c) Josef "Jeff" Sipek, 2007-2011
#

USAGE="[<patchname>]"
if [ -z "$GUILT_VERSION" ]; then
	echo "Invoking `basename $0` directly is no longer supported." >&2
	exit 1
fi

_main() {

if [ $# -gt 1 ]; then
	usage
fi

patchname="$1"

bottom=`git rev-parse refs/patches/$branch/$(head_n 1 < "$applied")`
base=`git rev-parse $bottom^`

if [ -z "$patchname" ]; then
	top=`git rev-parse HEAD`
else
	top=`grep "^$patchname$" "$applied"`
	if [ -z "$top" ]; then
		die "Cannot find patch '$patchname'. Is it applied?"
	fi
fi

getfiles()
{
	git diff-tree -r "$1^" "$1" | tr '\t' ' ' | cut -d' ' -f6
}

cache="$GUILT_DIR/$branch/.graphcache.$$"
mkdir "$cache"
trap "rm -rf \"$cache\"" 0

disp "digraph G {"

current="$top"

while [ "$current" != "$base" ]; do
	pname=`git show-ref | sed -n -e "
/^$current refs\/patches\/$branch/ {
	s,^$current refs/patches/$branch/,,
	p
	q
}"`
	[ -z "$pname" ] && pname="?"

	disp "# checking rev $current"
	disp "	\"$current\" [label=\"$pname\"]"

	# new "hash table"
	rm -f "$cache/dep"
	touch "$cache/dep"

	getfiles $current | while read f; do
		# hash the filename
		fh=`echo "$f" | sha1 | cut -d' ' -f1`
		if [ -e "$cache/$fh" ]; then
			# ok, something already touched this file before us
			cat "$cache/$fh" >> "$cache/dep"
		fi
		echo "$current" > "$cache/$fh"
	done

	sort -u "$cache/dep" | while read h; do
		disp "	\"$h\" -> \"$current\"; // ?"
	done

	current=`git rev-parse $current^`
done

disp "}"

}
