#!/bin/sh
set -e

case "$DGIT_ABSURD_DEBUG" in
''|0)	exec 3>/dev/null ;;
1)	exec 3>>../../gbp-pq-output ;;
*)	exec 3>>../../gbp-pq-output 2>&3 ;;
esac

exec 4>>../../absurd-apply-warnings

log () {
	echo >&3 "DGIT ABSURD GIT APPLY (DEBUG)  $*"
	echo >&2 "DGIT ABSURD GIT APPLY (STDERR) $*"
}

fail () {
	log "FAILED: $*"
	exit 127
}

self=${0%/*}
npath=${PATH#$self:}
if test "x$PATH" = "x$npath"; then
	fail "PATH FILTER FAIL ($0 $self $PATH)"
fi

filter_path () {
	PATH=$npath
}

squash_author () {
	author_vars='NAME EMAIL DATE'
	for var in in $author_vars; do
		eval "GIT_AUTHOR_$var=\$GIT_COMMITTER_$var"
	done
}

try_commit () { git commit-tree "$try_commit_obj" </dev/null >/dev/null; }

maybe_squash_author () {
	if   (set -e; filter_path;                try_commit); then return; fi
	if ! (set -e; filter_path; squash_author; try_commit); then return; fi
	read last <../../absurd-apply-applied
	echo >&4 \
 "dgit: warning: suppressed corrupted metadata! ($last)"
	squash_author
}

bypass=true
for arg in "$@"; do
	case "$arg" in
	apply)	bypass=false; break	;;
	commit-tree)
		# Work around #950446 in gbp
		echo >&3 "DGIT ABSURD GIT APPLY - COMMIT-TREE: $*"
		try_commit_obj="$2"
		maybe_squash_author
		bypass=true; break
		;;
	-*)				;;
	*)	bypass=true; break	;;
	esac
done

if $bypass; then
	filter_path
	echo >&3 "DGIT ABSURD GIT APPLY - BYPASS: $*"
	exec git "$@"
fi

log "NO BYPASS: $*"

case "$DGIT_ABSURD_DEBUG" in
''|0|1) ;;
*)	set -x ;;
esac

#exec >/dev/tty 2>&1

index=0
noo=0

for arg in "$@"; do
	case "$noo.$arg" in
	1.--index)
		index=1
		continue
		;;
	1.--whitespace=fix)
		continue
		;;
	?.-*)
		fail "UNKNOWN OPTION $arg ($*)"
		;;
	0.apply)
		;;
	1.*)	patch="$arg"
		;;
	*)
		fail "BAD USAGE $arg ($noo $*)"
	esac
	noo=$(( $noo + 1 ))
done

if [ $noo != 2 ]; then
	fail "NO PATCH ($*)"
fi

pwd=`pwd`
patch=${patch#$pwd/debian/patches/}
rm -f debian/patches/series

# Work around #848611.
# We need a stunt filename which the source package must not
# contain.  A trick is to use the commit hash of HEAD, whose
# hash value cannot appear in any file in its own tree.
omgwtf="dgit-omg-wtf-$(git rev-parse HEAD)"
cat <<END >debian/patches/$omgwtf
---
--- a/$omgwtf	2016-10-31 23:28:47.314155919 +0000
+++ b/$omgwtf	2016-12-18 22:40:01.870058270 +0000
@@ -0,0 +1 @@
+:
END
printf "%s\n" "$omgwtf" >debian/patches/series
printf "%s\n" "$patch" >>debian/patches/series

# Just in case some joker tries to patch .git/something
mv .git ../.git
set +e
dpkg-source --before-build .
rc=$?
set -e
rm -rf .git
mv ../.git .
test $rc = 0

rm -f $omgwtf debian/patches/$omgwtf

rm -rf .pc
git checkout debian/patches/series
git add -Af .

log "APPLIED $patch"
printf >../../absurd-apply-applied '%s\n' "$patch"
#printf 'APPLIED '; date --iso-8601=ns