#! /usr/bin/env 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.

usage()
{
	printf $"Usage: quilt pop [-afRqv] [--refresh] [num|patch]\n"
	if [ x$1 = x-h ]
	then
		printf $"
Remove patch(es) from the stack of applied patches.  Without options,
the topmost patch is removed.  When a number is specified, remove the
specified number of patches.  When a patch name is specified, remove
patches until the specified patch end up on top of the stack.  Patch
names may include the patches/ prefix, which means that filename
completion can be used.

-a	Remove all applied patches.

-f	Force remove. The state before the patch(es) were applied will
	be restored from backup files.

-R	Always verify if the patch removes cleanly; don't rely on
	timestamp checks.

-q	Quiet operation.

-v	Verbose operation.

--refresh
	Automatically refresh every patch before it gets unapplied.
"
		exit 0
	else
		exit 1
	fi
}

list_patches()
{
	local n patches
	patches=( $(applied_patches) )
	for ((n=${#patches[@]}-1; n>=0; n--))
	do
		if [ -n "$number" ]
		then
			(( number-- > 0 )) || break
		fi
		[ "${patches[n]}" = "$stop_at_patch" ] && break
		echo "${patches[n]}"
	done
}

files_may_have_changed()
{
	local patch=$1 file
	local patch_file=$(patch_file_name "$patch")

	if [ $? -ne 0 -o ! -e "$patch_file" \
	     -o ! -e "$QUILT_PC/$patch/.timestamp" \
	     -o ! "$QUILT_PC/$patch/.timestamp" -nt "$patch_file" ]
	then
		return 0
	fi

	for file in $(files_in_patch "$patch")
	do
		[ ! "$QUILT_PC/$patch/.timestamp" -nt "$file" ] && return 0
	done
	return 1
}

# Check if all changes have been folded back into the patch (quilt refresh),
# and report any pending changes.
check_for_pending_changes()
{
	local patch=$1
	local patch_file=$(patch_file_name "$patch")
	local workdir=$(gen_tempfile -d quilt) status=0

	if [ -d "$QUILT_PC/$patch" ]
	then
		local prefix=$QUILT_PC/$patch/
		[ ${prefix:0:1} == / ] || prefix=$PWD/$prefix
		if ! ( cd $workdir && \
		       $QUILT_DIR/scripts/backup-files -B "$prefix" -r -k -s - )
		then
			printf $"Failed to copy files to temporary directory\n" >&2
			rm -rf $workdir
			return 1
		fi
	fi

	if [ -s "$patch_file" ]
	then
		cat_file "$patch_file" \
		| patch -d $workdir $QUILT_PATCH_OPTS \
			$(patch_args "$patch") --no-backup-if-mismatch \
			-f >/dev/null 2>/dev/null
	fi

	local file file2 failed
	for file2 in $(files_in_patch "$patch")
	do
		file=$workdir/$file2
		[ -e "$file"  ] || file=/dev/null
		[ -e "$file2" ] || file2=/dev/null
		diff -q "$file" "$file2" > /dev/null || failed=1
	done

	if [ -n "$failed" ]
	then
		printf $"Patch %s does not remove cleanly (refresh it or enforce with -f)\n" \
		       "$(print_patch "$patch")" >&2
		status=1
	fi
	rm -rf $workdir

	return $status
}

remove_patch()
{
	local patch=$1 status=0

	trap "status=1" SIGINT
	if [ -z "$opt_force" ] && \
	   ( [ -n "$opt_remove" ] || files_may_have_changed "$patch" )
	then
		check_for_pending_changes "$patch" || status=1
	fi

	if [ $status -eq 0 ]
	then
		rm -f "$QUILT_PC/$patch/.timestamp"
		if [ -z "$(shopt -s nullglob ; echo "$QUILT_PC/$patch/"*)" ]
		then
			printf $"Patch %s appears to be empty, removing\n" \
			       "$(print_patch "$patch")"
			rmdir "$QUILT_PC/$patch"
			status=$?
		else
			printf $"Removing patch %s\n" "$(print_patch "$patch")"
			$QUILT_DIR/scripts/backup-files $silent -r -t -B "$QUILT_PC/$patch/" -
			status=$?
		fi
		remove_from_db "$patch"
		rm -f "$QUILT_PC/$patch~refresh"
	fi
	trap - SIGINT
	return $status
}

options=`getopt -o fRqvah --long refresh -- "$@"`

if [ $? -ne 0 ]
then
	usage
fi

eval set -- "$options"

while true
do
	case "$1" in
	-f)
		opt_force=1
		unset opt_remove
		shift ;;
	-R)
		opt_remove=1
		unset opt_force
		shift ;;
	-q)
		opt_quiet=1
		shift ;;
	-v)
		opt_verbose=1
		shift ;;
	-a)
		opt_all=1
		shift ;;
	-h)
		usage -h ;;
	--refresh)
		opt_refresh=1
		shift ;;
	--)
		shift
		break ;;
	esac
done

if [ $# -gt 1 -o \( -n "$opt_all" -a $# -ne 0 \) ]
then
	usage
fi

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

if [ -n "$opt_force" -a -n "$opt_refresh" ]
then
	printf $"Options %s and %s are mutually exclusive\n" "-f" "--refresh"
	exit 1
fi

if [ $# -eq 1 ]
then
	if is_numeric "$1"
	then
		number=$1
	else
		stop_at_patch=$(find_applied_patch "$1") || exit 1
	fi
else
	[ -n "$opt_all" ] || number=1
fi

[ -n "$opt_quiet" ] && silent=-s
[ -z "$opt_verbose" ] && silent_unless_verbose=-s

top=$(top_patch)
if [ -n "$top" -a -e "$QUILT_PC/$top~refresh" -a -z "$opt_force" ]
then
	printf $"Patch %s needs to be refreshed first.\n" \
	       "$(print_patch "$top")" >&2
	exit 1
fi

if ! patches=$(list_patches) 2>&1
then
	exit 1
elif [ -z "$patches" ]
then
	printf $"No patch removed\n" >&2
	exit 2
fi

# We will update the list of applied patches, which in turn will disable the
# consistency check. Enable it again if needed.
if [ -z "$opt_all" -a ! "$DB" -nt "$SERIES" ] && ! consistency_check
then
	rearm_check=1
fi

for patch in $patches
do
	[ -z "$opt_refresh" ] || quilt_command refresh $QUILT_REFRESH_ARGS
	if ! remove_patch "$patch"
	then
		exit 1
	fi
	[ -z "$opt_quiet" ] && echo
done

patch="$(top_patch)"
if [ -z "$patch" ]
then
	printf $"No patches applied\n"
else
	# Ensure that the files in the topmost patch have a link count
	# of one: This will automatically be the case in the usual
	# situations, but we don't want to risk file corruption in weird
	# corner cases such as files added to a patch but not modified.
	$QUILT_DIR/scripts/backup-files -L -s -B "$QUILT_PC/$patch/" -
	printf $"Now at patch %s\n" "$(print_patch "$patch")"

	[ -z "$rearm_check" ] || touch "$SERIES"
fi