#!/bin/sh
#
# Copyright (c) 2005, 2006 Junio C Hamano

SUBDIRECTORY_OK=Yes
OPTIONS_KEEPDASHDASH=
OPTIONS_SPEC="\
git am [options] [<mbox>|<Maildir>...]
git am [options] (--resolved | --skip | --abort)
--
i,interactive   run interactively
b,binary*       (historical option -- no-op)
3,3way          allow fall back on 3way merging if needed
q,quiet         be quiet
s,signoff       add a Signed-off-by line to the commit message
u,utf8          recode into utf8 (default)
k,keep          pass -k flag to git-mailinfo
whitespace=     pass it through git-apply
directory=      pass it through git-apply
C=              pass it through git-apply
p=              pass it through git-apply
patch-format=   format the patch(es) are in
reject          pass it through git-apply
resolvemsg=     override error message when patch failure occurs
r,resolved      to be used after a patch failure
skip            skip the current patch
abort           restore the original branch and abort the patching operation.
committer-date-is-author-date    lie about committer date
ignore-date     use current timestamp for author date
rebasing*       (internal use for git-rebase)"

. git-sh-setup
prefix=$(git rev-parse --show-prefix)
set_reflog_action am
require_work_tree
cd_to_toplevel

git var GIT_COMMITTER_IDENT >/dev/null ||
	die "You need to set your committer info first"

if git rev-parse --verify -q HEAD >/dev/null
then
	HAS_HEAD=yes
else
	HAS_HEAD=
fi

sq () {
	git rev-parse --sq-quote "$@"
}

stop_here () {
    echo "$1" >"$dotest/next"
    exit 1
}

stop_here_user_resolve () {
    if [ -n "$resolvemsg" ]; then
	    printf '%s\n' "$resolvemsg"
	    stop_here $1
    fi
    cmdline="git am"
    if test '' != "$interactive"
    then
        cmdline="$cmdline -i"
    fi
    if test '' != "$threeway"
    then
        cmdline="$cmdline -3"
    fi
    echo "When you have resolved this problem run \"$cmdline --resolved\"."
    echo "If you would prefer to skip this patch, instead run \"$cmdline --skip\"."
    echo "To restore the original branch and stop patching run \"$cmdline --abort\"."

    stop_here $1
}

go_next () {
	rm -f "$dotest/$msgnum" "$dotest/msg" "$dotest/msg-clean" \
		"$dotest/patch" "$dotest/info"
	echo "$next" >"$dotest/next"
	this=$next
}

cannot_fallback () {
	echo "$1"
	echo "Cannot fall back to three-way merge."
	exit 1
}

fall_back_3way () {
    O_OBJECT=`cd "$GIT_OBJECT_DIRECTORY" && pwd`

    rm -fr "$dotest"/patch-merge-*
    mkdir "$dotest/patch-merge-tmp-dir"

    # First see if the patch records the index info that we can use.
    git apply --build-fake-ancestor "$dotest/patch-merge-tmp-index" \
	"$dotest/patch" &&
    GIT_INDEX_FILE="$dotest/patch-merge-tmp-index" \
    git write-tree >"$dotest/patch-merge-base+" ||
    cannot_fallback "Repository lacks necessary blobs to fall back on 3-way merge."

    say Using index info to reconstruct a base tree...
    if GIT_INDEX_FILE="$dotest/patch-merge-tmp-index" \
	git apply --cached <"$dotest/patch"
    then
	mv "$dotest/patch-merge-base+" "$dotest/patch-merge-base"
	mv "$dotest/patch-merge-tmp-index" "$dotest/patch-merge-index"
    else
        cannot_fallback "Did you hand edit your patch?
It does not apply to blobs recorded in its index."
    fi

    test -f "$dotest/patch-merge-index" &&
    his_tree=$(GIT_INDEX_FILE="$dotest/patch-merge-index" git write-tree) &&
    orig_tree=$(cat "$dotest/patch-merge-base") &&
    rm -fr "$dotest"/patch-merge-* || exit 1

    say Falling back to patching base and 3-way merge...

    # This is not so wrong.  Depending on which base we picked,
    # orig_tree may be wildly different from ours, but his_tree
    # has the same set of wildly different changes in parts the
    # patch did not touch, so recursive ends up canceling them,
    # saying that we reverted all those changes.

    eval GITHEAD_$his_tree='"$FIRSTLINE"'
    export GITHEAD_$his_tree
    if test -n "$GIT_QUIET"
    then
	    export GIT_MERGE_VERBOSITY=0
    fi
    git-merge-recursive $orig_tree -- HEAD $his_tree || {
	    git rerere
	    echo Failed to merge in the changes.
	    exit 1
    }
    unset GITHEAD_$his_tree
}

clean_abort () {
	test $# = 0 || echo >&2 "$@"
	rm -fr "$dotest"
	exit 1
}

patch_format=

check_patch_format () {
	# early return if patch_format was set from the command line
	if test -n "$patch_format"
	then
		return 0
	fi

	# we default to mbox format if input is from stdin and for
	# directories
	if test $# = 0 || test "x$1" = "x-" || test -d "$1"
	then
		patch_format=mbox
		return 0
	fi

	# otherwise, check the first few lines of the first patch to try
	# to detect its format
	{
		read l1
		read l2
		read l3
		case "$l1" in
		"From "* | "From: "*)
			patch_format=mbox
			;;
		'# This series applies on GIT commit'*)
			patch_format=stgit-series
			;;
		"# HG changeset patch")
			patch_format=hg
			;;
		*)
			# if the second line is empty and the third is
			# a From, Author or Date entry, this is very
			# likely an StGIT patch
			case "$l2,$l3" in
			,"From: "* | ,"Author: "* | ,"Date: "*)
				patch_format=stgit
				;;
			*)
				;;
			esac
			;;
		esac
	} < "$1" || clean_abort
}

split_patches () {
	case "$patch_format" in
	mbox)
		git mailsplit -d"$prec" -o"$dotest" -b -- "$@" > "$dotest/last" ||
		clean_abort
		;;
	stgit-series)
		if test $# -ne 1
		then
			clean_abort "Only one StGIT patch series can be applied at once"
		fi
		series_dir=`dirname "$1"`
		series_file="$1"
		shift
		{
			set x
			while read filename
			do
				set "$@" "$series_dir/$filename"
			done
			# remove the safety x
			shift
			# remove the arg coming from the first-line comment
			shift
		} < "$series_file" || clean_abort
		# set the patch format appropriately
		patch_format=stgit
		# now handle the actual StGIT patches
		split_patches "$@"
		;;
	stgit)
		this=0
		for stgit in "$@"
		do
			this=`expr "$this" + 1`
			msgnum=`printf "%0${prec}d" $this`
			# Perl version of StGIT parse_patch. The first nonemptyline
			# not starting with Author, From or Date is the
			# subject, and the body starts with the next nonempty
			# line not starting with Author, From or Date
			perl -ne 'BEGIN { $subject = 0 }
				if ($subject > 1) { print ; }
				elsif (/^\s+$/) { next ; }
				elsif (/^Author:/) { print s/Author/From/ ; }
				elsif (/^(From|Date)/) { print ; }
				elsif ($subject) {
					$subject = 2 ;
					print "\n" ;
					print ;
				} else {
					print "Subject: ", $_ ;
					$subject = 1;
				}
			' < "$stgit" > "$dotest/$msgnum" || clean_abort
		done
		echo "$this" > "$dotest/last"
		this=
		msgnum=
		;;
	*)
		clean_abort "Patch format $patch_format is not supported."
		;;
	esac
}

prec=4
dotest="$GIT_DIR/rebase-apply"
sign= utf8=t keep= skip= interactive= resolved= rebasing= abort=
resolvemsg= resume=
git_apply_opt=
committer_date_is_author_date=
ignore_date=

while test $# != 0
do
	case "$1" in
	-i|--interactive)
		interactive=t ;;
	-b|--binary)
		: ;;
	-3|--3way)
		threeway=t ;;
	-s|--signoff)
		sign=t ;;
	-u|--utf8)
		utf8=t ;; # this is now default
	--no-utf8)
		utf8= ;;
	-k|--keep)
		keep=t ;;
	-r|--resolved)
		resolved=t ;;
	--skip)
		skip=t ;;
	--abort)
		abort=t ;;
	--rebasing)
		rebasing=t threeway=t keep=t ;;
	-d|--dotest)
		die "-d option is no longer supported.  Do not use."
		;;
	--resolvemsg)
		shift; resolvemsg=$1 ;;
	--whitespace|--directory)
		git_apply_opt="$git_apply_opt $(sq "$1=$2")"; shift ;;
	-C|-p)
		git_apply_opt="$git_apply_opt $(sq "$1$2")"; shift ;;
	--patch-format)
		shift ; patch_format="$1" ;;
	--reject)
		git_apply_opt="$git_apply_opt $1" ;;
	--committer-date-is-author-date)
		committer_date_is_author_date=t ;;
	--ignore-date)
		ignore_date=t ;;
	-q|--quiet)
		GIT_QUIET=t ;;
	--)
		shift; break ;;
	*)
		usage ;;
	esac
	shift
done

# If the dotest directory exists, but we have finished applying all the
# patches in them, clear it out.
if test -d "$dotest" &&
   last=$(cat "$dotest/last") &&
   next=$(cat "$dotest/next") &&
   test $# != 0 &&
   test "$next" -gt "$last"
then
   rm -fr "$dotest"
fi

if test -d "$dotest"
then
	case "$#,$skip$resolved$abort" in
	0,*t*)
		# Explicit resume command and we do not have file, so
		# we are happy.
		: ;;
	0,)
		# No file input but without resume parameters; catch
		# user error to feed us a patch from standard input
		# when there is already $dotest.  This is somewhat
		# unreliable -- stdin could be /dev/null for example
		# and the caller did not intend to feed us a patch but
		# wanted to continue unattended.
		test -t 0
		;;
	*)
		false
		;;
	esac ||
	die "previous rebase directory $dotest still exists but mbox given."
	resume=yes

	case "$skip,$abort" in
	t,t)
		die "Please make up your mind. --skip or --abort?"
		;;
	t,)
		git rerere clear
		git read-tree --reset -u HEAD HEAD
		orig_head=$(cat "$GIT_DIR/ORIG_HEAD")
		git reset HEAD
		git update-ref ORIG_HEAD $orig_head
		;;
	,t)
		if test -f "$dotest/rebasing"
		then
			exec git rebase --abort
		fi
		git rerere clear
		test -f "$dotest/dirtyindex" || {
			git read-tree --reset -u HEAD ORIG_HEAD
			git reset ORIG_HEAD
		}
		rm -fr "$dotest"
		exit ;;
	esac
	rm -f "$dotest/dirtyindex"
else
	# Make sure we are not given --skip, --resolved, nor --abort
	test "$skip$resolved$abort" = "" ||
		die "Resolve operation not in progress, we are not resuming."

	# Start afresh.
	mkdir -p "$dotest" || exit

	if test -n "$prefix" && test $# != 0
	then
		first=t
		for arg
		do
			test -n "$first" && {
				set x
				first=
			}
			case "$arg" in
			/*)
				set "$@" "$arg" ;;
			*)
				set "$@" "$prefix$arg" ;;
			esac
		done
		shift
	fi

	check_patch_format "$@"

	split_patches "$@"

	# -s, -u, -k, --whitespace, -3, -C, -q and -p flags are kept
	# for the resuming session after a patch failure.
	# -i can and must be given when resuming.
	echo " $git_apply_opt" >"$dotest/apply-opt"
	echo "$threeway" >"$dotest/threeway"
	echo "$sign" >"$dotest/sign"
	echo "$utf8" >"$dotest/utf8"
	echo "$keep" >"$dotest/keep"
	echo "$GIT_QUIET" >"$dotest/quiet"
	echo 1 >"$dotest/next"
	if test -n "$rebasing"
	then
		: >"$dotest/rebasing"
	else
		: >"$dotest/applying"
		if test -n "$HAS_HEAD"
		then
			git update-ref ORIG_HEAD HEAD
		else
			git update-ref -d ORIG_HEAD >/dev/null 2>&1
		fi
	fi
fi

case "$resolved" in
'')
	case "$HAS_HEAD" in
	'')
		files=$(git ls-files) ;;
	?*)
		files=$(git diff-index --cached --name-only HEAD --) ;;
	esac || exit
	if test "$files"
	then
		test -n "$HAS_HEAD" && : >"$dotest/dirtyindex"
		die "Dirty index: cannot apply patches (dirty: $files)"
	fi
esac

if test "$(cat "$dotest/utf8")" = t
then
	utf8=-u
else
	utf8=-n
fi
if test "$(cat "$dotest/keep")" = t
then
	keep=-k
fi
if test "$(cat "$dotest/quiet")" = t
then
	GIT_QUIET=t
fi
if test "$(cat "$dotest/threeway")" = t
then
	threeway=t
fi
git_apply_opt=$(cat "$dotest/apply-opt")
if test "$(cat "$dotest/sign")" = t
then
	SIGNOFF=`git var GIT_COMMITTER_IDENT | sed -e '
			s/>.*/>/
			s/^/Signed-off-by: /'
		`
else
	SIGNOFF=
fi

last=`cat "$dotest/last"`
this=`cat "$dotest/next"`
if test "$skip" = t
then
	this=`expr "$this" + 1`
	resume=
fi

if test "$this" -gt "$last"
then
	say Nothing to do.
	rm -fr "$dotest"
	exit
fi

while test "$this" -le "$last"
do
	msgnum=`printf "%0${prec}d" $this`
	next=`expr "$this" + 1`
	test -f "$dotest/$msgnum" || {
		resume=
		go_next
		continue
	}

	# If we are not resuming, parse and extract the patch information
	# into separate files:
	#  - info records the authorship and title
	#  - msg is the rest of commit log message
	#  - patch is the patch body.
	#
	# When we are resuming, these files are either already prepared
	# by the user, or the user can tell us to do so by --resolved flag.
	case "$resume" in
	'')
		git mailinfo $keep $utf8 "$dotest/msg" "$dotest/patch" \
			<"$dotest/$msgnum" >"$dotest/info" ||
			stop_here $this

		# skip pine's internal folder data
		grep '^Author: Mail System Internal Data$' \
			<"$dotest"/info >/dev/null &&
			go_next && continue

		test -s "$dotest/patch" || {
			echo "Patch is empty.  Was it split wrong?"
			stop_here $this
		}
		if test -f "$dotest/rebasing" &&
			commit=$(sed -e 's/^From \([0-9a-f]*\) .*/\1/' \
				-e q "$dotest/$msgnum") &&
			test "$(git cat-file -t "$commit")" = commit
		then
			git cat-file commit "$commit" |
			sed -e '1,/^$/d' >"$dotest/msg-clean"
		else
			SUBJECT="$(sed -n '/^Subject/ s/Subject: //p' "$dotest/info")"
			case "$keep_subject" in -k)  SUBJECT="[PATCH] $SUBJECT" ;; esac

			(printf '%s\n\n' "$SUBJECT"; cat "$dotest/msg") |
				git stripspace > "$dotest/msg-clean"
		fi
		;;
	esac

	GIT_AUTHOR_NAME="$(sed -n '/^Author/ s/Author: //p' "$dotest/info")"
	GIT_AUTHOR_EMAIL="$(sed -n '/^Email/ s/Email: //p' "$dotest/info")"
	GIT_AUTHOR_DATE="$(sed -n '/^Date/ s/Date: //p' "$dotest/info")"

	if test -z "$GIT_AUTHOR_EMAIL"
	then
		echo "Patch does not have a valid e-mail address."
		stop_here $this
	fi

	export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE

	case "$resume" in
	'')
	    if test '' != "$SIGNOFF"
	    then
		LAST_SIGNED_OFF_BY=`
		    sed -ne '/^Signed-off-by: /p' \
		    "$dotest/msg-clean" |
		    sed -ne '$p'
		`
		ADD_SIGNOFF=`
		    test "$LAST_SIGNED_OFF_BY" = "$SIGNOFF" || {
		    test '' = "$LAST_SIGNED_OFF_BY" && echo
		    echo "$SIGNOFF"
		}`
	    else
		ADD_SIGNOFF=
	    fi
	    {
		if test -s "$dotest/msg-clean"
		then
			cat "$dotest/msg-clean"
		fi
		if test '' != "$ADD_SIGNOFF"
		then
			echo "$ADD_SIGNOFF"
		fi
	    } >"$dotest/final-commit"
	    ;;
	*)
		case "$resolved$interactive" in
		tt)
			# This is used only for interactive view option.
			git diff-index -p --cached HEAD -- >"$dotest/patch"
			;;
		esac
	esac

	resume=
	if test "$interactive" = t
	then
	    test -t 0 ||
	    die "cannot be interactive without stdin connected to a terminal."
	    action=again
	    while test "$action" = again
	    do
		echo "Commit Body is:"
		echo "--------------------------"
		cat "$dotest/final-commit"
		echo "--------------------------"
		printf "Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all "
		read reply
		case "$reply" in
		[yY]*) action=yes ;;
		[aA]*) action=yes interactive= ;;
		[nN]*) action=skip ;;
		[eE]*) git_editor "$dotest/final-commit"
		       action=again ;;
		[vV]*) action=again
		       LESS=-S ${PAGER:-less} "$dotest/patch" ;;
		*)     action=again ;;
		esac
	    done
	else
	    action=yes
	fi
	FIRSTLINE=$(sed 1q "$dotest/final-commit")

	if test $action = skip
	then
		go_next
		continue
	fi

	if test -x "$GIT_DIR"/hooks/applypatch-msg
	then
		"$GIT_DIR"/hooks/applypatch-msg "$dotest/final-commit" ||
		stop_here $this
	fi

	say "Applying: $FIRSTLINE"

	case "$resolved" in
	'')
		# When we are allowed to fall back to 3-way later, don't give
		# false errors during the initial attempt.
		squelch=
		if test "$threeway" = t
		then
			squelch='>/dev/null 2>&1 '
		fi
		eval "git apply $squelch$git_apply_opt"' --index "$dotest/patch"'
		apply_status=$?
		;;
	t)
		# Resolved means the user did all the hard work, and
		# we do not have to do any patch application.  Just
		# trust what the user has in the index file and the
		# working tree.
		resolved=
		git diff-index --quiet --cached HEAD -- && {
			echo "No changes - did you forget to use 'git add'?"
			stop_here_user_resolve $this
		}
		unmerged=$(git ls-files -u)
		if test -n "$unmerged"
		then
			echo "You still have unmerged paths in your index"
			echo "did you forget to use 'git add'?"
			stop_here_user_resolve $this
		fi
		apply_status=0
		git rerere
		;;
	esac

	if test $apply_status = 1 && test "$threeway" = t
	then
		if (fall_back_3way)
		then
		    # Applying the patch to an earlier tree and merging the
		    # result may have produced the same tree as ours.
		    git diff-index --quiet --cached HEAD -- && {
			say No changes -- Patch already applied.
			go_next
			continue
		    }
		    # clear apply_status -- we have successfully merged.
		    apply_status=0
		fi
	fi
	if test $apply_status != 0
	then
		printf 'Patch failed at %s %s\n' "$msgnum" "$FIRSTLINE"
		stop_here_user_resolve $this
	fi

	if test -x "$GIT_DIR"/hooks/pre-applypatch
	then
		"$GIT_DIR"/hooks/pre-applypatch || stop_here $this
	fi

	tree=$(git write-tree) &&
	commit=$(
		if test -n "$ignore_date"
		then
			GIT_AUTHOR_DATE=
		fi
		parent=$(git rev-parse --verify -q HEAD) ||
		say >&2 "applying to an empty history"

		if test -n "$committer_date_is_author_date"
		then
			GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
			export GIT_COMMITTER_DATE
		fi &&
		git commit-tree $tree ${parent:+-p} $parent <"$dotest/final-commit"
	) &&
	git update-ref -m "$GIT_REFLOG_ACTION: $FIRSTLINE" HEAD $commit $parent ||
	stop_here $this

	if test -x "$GIT_DIR"/hooks/post-applypatch
	then
		"$GIT_DIR"/hooks/post-applypatch
	fi

	go_next
done

git gc --auto

rm -fr "$dotest"