#!/bin/sh

setglobal USAGE = '"(edit [-F <file> | -m <msg>] | show) [commit]'"
source git-sh-setup

test -z $1 && usage
setglobal ACTION = $1; shift

test -z $GIT_NOTES_REF && setglobal GIT_NOTES_REF = $[git config core.notesref]
test -z $GIT_NOTES_REF && setglobal GIT_NOTES_REF = '"refs/notes/commits'"

setglobal MESSAGE = ''
while test $# != 0
{
	match $1 {
	with -m
		test $ACTION = "edit" || usage
		shift
		if test "$Argc" = "0" {
			die "error: option -m needs an argument"
		} else {
			if test -z $MESSAGE {
				setglobal MESSAGE = $1
			} else {
				setglobal MESSAGE = ""$MESSAGE

$1""
			}
			shift
		}
		
	with -F
		test $ACTION = "edit" || usage
		shift
		if test "$Argc" = "0" {
			die "error: option -F needs an argument"
		} else {
			if test -z $MESSAGE {
				setglobal MESSAGE = $[cat $1]
			} else {
				setglobal MESSAGE = ""$MESSAGE

$[cat $1]""
			}
			shift
		}
		
	with -*
		usage
		
	with *
		break
		
	}
}

setglobal COMMIT = $[git rev-parse --verify --default HEAD @Argv] ||
die "Invalid commit: $ifsjoin(Argv)"

match $ACTION {
with edit
	if test $(GIT_NOTES_REF#refs/notes/) = $GIT_NOTES_REF {
		die "Refusing to edit notes in $GIT_NOTES_REF (outside of refs/notes/)"
	}

	setglobal MSG_FILE = ""$GIT_DIR/new-notes-$COMMIT""
	setglobal GIT_INDEX_FILE = ""$MSG_FILE.idx""
	export GIT_INDEX_FILE

	trap '
		test -f "$MSG_FILE" && rm "$MSG_FILE"
		test -f "$GIT_INDEX_FILE" && rm "$GIT_INDEX_FILE"
	' 0

	setglobal CURRENT_HEAD = $[git show-ref $GIT_NOTES_REF | cut -f 1 -d ' ]
	if test -z $CURRENT_HEAD {
		setglobal PARENT = ''
	} else {
		setglobal PARENT = ""-p $CURRENT_HEAD""
		git read-tree $GIT_NOTES_REF || die "Could not read index"
	}

	if test -z $MESSAGE {
		env GIT_NOTES_REF= git log -1 $COMMIT | sed "s/^/#/" > $MSG_FILE
		if test ! -z $CURRENT_HEAD {
			git cat-file blob :$COMMIT >> $MSG_FILE !2 > /dev/null
		}
		setglobal core_editor = $[git config core.editor]
		$(GIT_EDITOR:-${core_editor:-${VISUAL:-${EDITOR:-vi}}}) $MSG_FILE
	} else {
		echo $MESSAGE > $MSG_FILE
	}

	grep -v ^# < $MSG_FILE | git stripspace > "$MSG_FILE".processed
	mv "$MSG_FILE".processed $MSG_FILE
	if test -s $MSG_FILE {
		setglobal BLOB = $[git hash-object -w $MSG_FILE] ||
			die "Could not write into object database"
		git update-index --add --cacheinfo 0644 $BLOB $COMMIT ||
			die "Could not write index"
	} else {
		test -z $CURRENT_HEAD &&
			die "Will not initialise with empty tree"
		git update-index --force-remove $COMMIT ||
			die "Could not update index"
	}

	setglobal TREE = $[git write-tree] || die "Could not write tree"
	setglobal NEW_HEAD = $[echo Annotate $COMMIT | git commit-tree $TREE $PARENT] ||
		die "Could not annotate"
	git update-ref -m "Annotate $COMMIT" \
		$GIT_NOTES_REF $NEW_HEAD $CURRENT_HEAD

with show
	git rev-parse -q --verify "$GIT_NOTES_REF":$COMMIT > /dev/null ||
		die "No note for commit $COMMIT."
	git show "$GIT_NOTES_REF":$COMMIT

with *
	usage
}