#!/bin/bash
#
# LTSI helper script to generate a git tree from the quilt LTSI tree
#
# Copyright 2012 Greg Kroah-Hartman
# Copyright 2012 Linux Foundation
#
# Licensed under the GPLv2 only.
#
#

if [ "$1" = "--help" ]; then
	echo -e "Usage: `basename $0` [--help | -a]"
	echo -e "  If no options are specified the script assumes no LTSI branch has been created"
	echo -e "  [--help]\tShows usage information"
	echo -e "  [-a]\t\tAuto resume after last applied patch (skipping branch creation)"
	exit 0
fi

UPSTREAM="git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git"
if [ "$1" = "-a" ]; then
	AUTORESUME=1
	shift
fi

DIR=`dirname $0 |sed 's/scripts$//'`
SERIES=$DIR/series

if [ ! -f "$SERIES" ]; then
	echo Cant find series file at $SERIES
	exit 1
fi

if [ -n "$2" ];then
	START=$2
fi

diffstat --help > /dev/null 2>&1
if [ $? != 0 ]; then
	echo It appears you dont have diffstat installed.
	echo Please install it.
	exit 1
fi

if [ ! -d .git ]; then
	echo There does not appear to be a git tree in this dir.
	echo You need a copy of:
	echo $UPSTREAM
	echo as a baseline.
	exit 1
fi

KVER=`cat $DIR/KERNEL_VERSION`
git rev-parse -q --verify v$KVER > /dev/null
if [ $? != 0 ]; then
	echo There is no \"v$KVER\" in this git repository.  Perhaps pull from:
	echo $UPSTREAM
	echo to get this tag?
	exit 1
fi

if [ -n "$AUTORESUME" ]; then
	PARENT=`git show|grep ommit|grep 'pstream\|herry\|tip'|sed 's/.* \([0-9a-f]\+\).*/\1/'`
	CLEN=`echo $PARENT|wc -c`
	if [ $CLEN -ne 41 ]; then
		echo Failed to autodetect resume point -- no parent ID
		echo falling back to diffstat detection
		DS1=`mktemp`
		DS2=`mktemp`
		git show | diffstat -p0 > $DS1
		for i in $DIR/patches\.*/*\.patch ; do
			cat $i | diffstat -p0 > $DS2
			cmp -s $DS1 $DS2
			if [ $? = 0 ]; then
				START=$i
				break
			fi
		done
		rm $DS1 $DS2
		if [ -z "$START" ]; then
			echo diffstat detection failed
			exit 1
		fi
	fi

	if [ -z "$START" ]; then
		START=`grep -l $PARENT $DIR/patches.*/*`
	fi

	if [ -z "$START" ]; then
		echo Failed to autodetect resume point - no matching filename
		echo for patch that created current HEAD commit $PARENT
		exit 1
	fi

	START=`echo $START|sed 's/^.*patches\./patches./'`
	echo resuming from current \"$START\"
fi

if [ -z "$START" ]; then
	echo creating branch "$KVER-ltsi"
	git checkout -b $KVER-ltsi v$KVER
	if [ $? != 0 ]; then
		echo Creation of branch $KVER-ltsi failed
		exit 1
	fi
fi

COUNT=`cat $SERIES | grep '^[a-zA-Z0-9_]'|wc -l`
APPLIED=0

for i in `cat $SERIES | grep '^[a-zA-Z0-9_]'`
do

	APPLIED=$[$APPLIED+1]

	if [ -n "$START" ]; then
		if [ "$START" != "$i" ];then
			continue
		else
			START=""
			continue
		fi
	fi

	if [ ! -f "$DIR/$i" ];then
		echo $DIR/$i doesnt exist
		break
	fi

	echo -n "($APPLIED/$COUNT) "
	git am $DIR/$i
	if [ $? != 0 ];then
		echo git am of $i failed. STBU.
		exit 1
	fi
done