#! /bin/bash

#  This script is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License version 2 as
#  published by the Free Software Foundation.
#
#  See the COPYING and AUTHORS files for more details.

# Read in library functions
if ! [ -r @LIB@/patchfns ]
then
	echo "Cannot read library @LIB@/patchfns" >&2
	exit 1
fi
. @LIB@/patchfns

usage()
{
	local redirect
	if [ x$1 != x-h ]
	then
		redirect='>&2'
	fi
	echo "Usage: refpatch [-cfz] [patchname]" $redirect
	
	if [ x$1 = x-h ]
	then
		cat <<EOF

Refresh an applied patch. Refreshes the specified patch, or
the topmost patch by default. Documentation on top of the
actual patch is retained.

It is possible to refresh patches that are not on top.
If any patches on top of the patch to refresh modify the
same files, refpatch prints out the file and patch names.
If there are any such conflicts, patches can still be
refreshed with -f. In that case refpatch will print a
warning for each thus shadowed file, changes by more
recent patches will be ignored, and only changes in files
that have not been modified by any more recent patches
will end up in the specified patch.

-c	Write to standard output only; don't update the patch.

-f	Force refresh, even if more recent patches modify
	some of the same files.

-z	Write to standard output the changes that have been
	made relative to the topmost or specified patch.

EOF
		exit 0
	else
		exit 1
	fi
}

fix_diff_header()
{
	local from=$1 to=$2
	sed -e 's:^--- [^ \t]*:--- '"$from"':' \
	    -e 's:^+++ [^ \t]*:+++ '"$to"':'
}

diff_file()
{
	local file=$1 patch=$2 status=0
	local next_patch=$(next_patch_for_file $patch $file)
	local old_file=$(backup_file_name $patch $file)
	local new_file file_was_shadowed
	if [ -n "$next_patch" ]
	then
		new_file=$(backup_file_name $next_patch $file)
		file_was_shadowed=1
	else
		new_file=$file
	fi

	if [ ! -e $old_file -a ! -e $new_file ]
	then
		echo "File $new_file does not exist" >&2
		return 0
	fi
	local dir=$(basename $PWD) suffix=${patch//\//_} old_hdr new_hdr
	if [ $opt_strip -eq 0 ]
	then
		old_hdr=$file~$suffix
		new_hdr=$file
	else
		old_hdr=$dir~$suffix/$file
		new_hdr=$dir/$file
	fi

	if [ -z "$opt_post" ]
	then
		echo diff -Nu $DIFF_OPTS $old_file $new_file >&2
		diff -Nu $DIFF_OPTS $old_file $new_file |
		fix_diff_header $old_hdr $new_hdr
		status=$?

		if [ $status -eq 0 -a -n "$file_was_shadowed" ]
		then
			status=2
		fi
	elif [ -n "$file_was_shadowed" ]
	then
		return 0
	else
		local tmp=$(mktemp /tmp/patch-scripts.XXXXXX)
		if ! filterdiff $(patch_args $patch) -i $file \
				$(patch_file_name $patch) \
		     | patch -s -o $tmp $old_file --no-backup-if-mismatch
		then
			echo "Failed to patch temporary file" >&2
			return 1
		fi

		echo diff -Nu $DIFF_OPTS $new_file.orig $new_file >&2
		diff -Nu $DIFF_OPTS $tmp $new_file |
		fix_diff_header $new_file.orig $new_hdr
		status=$?
		rm -f $tmp
	fi
	return $status
}

die ()
{
	local status=$1
	[ -n "$tmp" ] && rm -f $tmp
	[ -n "$tmp2" ] && rm -f $tmp2
	[ -n "$workdir" ] && rm -rf $workdir
	exit $status
}

options=`getopt -o p:fczh -- "$@"`

if [ $? -ne 0 ]
then
	usage
fi

eval set -- "$options"

while true
do
	case "$1" in
	-p)
		opt_strip=$2
		shift 2 ;;
	-c)
		opt_stdout=1
		shift ;;
	-f)
		opt_force=1
		shift ;;
	-z)
		opt_post=1
		opt_stdout=1
		shift ;;
	-h)
		usage -h ;;
	--)
		shift
		break ;;
	esac
done

if [ $# -eq 1 ]
then
	opt_patch=$1
elif [ $# -gt 1 ]
then
	usage
fi

if [ -n "$opt_patch" ]
then
	patch=$(stripit $opt_patch)
else
	patch=$(top_patch)
	if [ -z "$patch" ]
	then
		echo "No patches seem to be applied" >&2
		exit 1
	fi
fi

if ! is_applied "$patch"
then
	echo "Patch $patch is not applied" >&2
	exit 1
fi

if [ -z "$opt_strip" ]
then
	opt_strip=$(patch_strip_level $patch)
fi
if [ $opt_strip -gt 1 ]
then
	echo "Cannot refresh patches with -p$opt_strip," \
	     "please specify -p0 or -p1 instead" >&2
	exit 1
fi

trap "die 1" SIGTERM

if [ -z "$opt_stdout" ]
then
	tmp=$(mktemp /tmp/patch-scripts.XXXXXX)
fi

if [ -n "$opt_post" ]
then
	patch_file=$(patch_file_name $patch)
	files=$(files_in_patch $patch)
	workdir=$(mktemp -d patch-scripts.XXXXXX)
	pwd=$PWD

	if ! cd .pc/$patch
	then
		echo "Cannot change into .pc/$patch"
		die 1
	fi
	if ! cp -l --parents $files $pwd/$workdir/
	then
		echo "Failed to copy files to temporary directory"
		die 1
	fi
	if ! cd $pwd/$workdir
	then
		echo "Cannot change to temporary directory"
		die 1
	fi
	if ! patch $(patch_args $patch) --no-backup-if-mismatch \
		-E -i $pwd/$patch_file >/dev/null 2>/dev/null
	then
		echo "Failed to patch temporary files"
		die 1
	fi
	if ! cd $pwd
	then
		echo "Cannot change to source directory"
		die 1
	fi

	for file in $(files_in_patch $patch)
	do
		suffix=${patch//\//_}
		if [ $opt_strip -eq 0 ]
		then
			old_hdr=$file.orig
			new_hdr=$file
		else
			dir=$(basename $PWD)
			old_hdr=$dir.orig/$file
			new_hdr=$dir/$file
		fi
		echo diff -Nu $DIFF_OPTS $new_hdr.orig $new_hdr >&2
		diff -Nu $DIFF_OPTS $workdir/$file $file \
		| fix_diff_header $old_hdr $new_hdr
		if [ $? -ne 0 ]
		then
			status=1
		fi
	done
	die $status
else
	for file in $(files_in_patch $patch)
	do
		diff_file $file $patch
		status=$?
		if [ $status -eq 2 ]
		then
			files_were_shadowed=1
		elif [ $status -ne 0 ]
		then
			echo "Diff failed, aborting." >&2
			die 1
		fi

		if [ -n "$files_were_shadowed" -a -z "$opt_force" ]
		then
			echo "More recent patches modify the same files." \
			     "Enforce refresh with -f." >&2
			die 1
		fi
	done
fi \
| if [ -z "$opt_stdout" ]
then
	cat > $tmp
else
	cat
fi
	
if [ -z "$opt_stdout" ]
then
	if ! [ -s $tmp ]
	then
		echo "Nothing in patch $patch" >&2
		die 1
	fi

	patch_file=$(patch_file_name $patch)

	trap "" SIGINT

	if [ ! -e $patch_file ] || grep -q '^%patch$' $patch_file
	then
		touch $patch_file
		cat $tmp \
		| @LIB@/parse-patch -u patch $patch_file
	else
		tmp2=$(mktemp /tmp/patch-scripts.XXXXXX) &&
		patch_description $patch_file > $tmp2 &&
		cat $tmp >> $tmp2 &&
		mv $tmp2 $patch_file
	fi
	status=$?

	rm -f $tmp $tmp2
	if [ $status -ne 0 ]
	then
		die 1
	fi

	rm -f $(pc_file_name $patch)~forced
	echo "Refreshed patch $patch"
	if ! change_db_strip_level -p$opt_strip $patch
	then
		die 1
	fi
fi