## functions ## {{{1
## assert ## {{{2
assert() {
	"$@" || die "assertion failed: $*"
}

## authorinfo ## {{{2
authorinfo() {
	# XXX: implement parsing .ubergit/author

	personfromcommit "$1" "author" "AUTHOR"
}

## base ## {{{2
base() {
	assert is_topic "$1"

	git cat-file blob "$1:.ubergit/base" \
	| sed -e 's/ *#.*//; /^$/d'
}

## commitenv ## {{{2
commitenv() {
	local commit
	commit="$1"; shift

	eval env $(authorinfo "$commit") $(committerinfo "$commit") "$(sq "$@")"
}

## commiterinfo ## {{{2
committerinfo() {
	assert is_topic "$1"

	personfromcommit "$1" "committer" "COMMITTER"
}

## debug ## {{{2
debug() {
	echo -- "$*" > /dev/tty
}

## deps ## {{{2
deps() {
	assert test "$#" = "1"
	assert is_sha1 "$1"
	if is_topic "$1"; then
		local base deplines

		base="$(base "$1")"

		# this removes the final newline
		git cat-file blob "$base:.ubergit/deps" | sed -e 's/ *#.*//; /^$/d'
	fi
}

## die ## {{{2
die() {
	printf "fatal: %s\n" "$*" >&2
	exit 1
}

## export_rev_chk ## {{{2
export_rev_chk() {
	assert is_sha1 "$1"
	eval test -z "\$exported_$1"
}

## export_rev_cmd ## {{{2
export_rev_cmd() {
	local deps parent exported

	assert is_sha1 "$1"

	# XXX: is this portable?
	deps="$(printf "%s" "$(deps "$1")" | tr '\012' ' ')"

	case "$deps" in
	"")
		eval "exported_$1=$1"
		return
		;;
	*" "*)
		# >1 dependency
		parent="$(printf "exported base for $1\n" \
		| commitenv "$1" git commit-tree "$(pretty_tree "$(base "$1")")" $(set -f; for p in $deps; do eval printf "%s" "\" -p \$exported_$p\""; done))"
		;;
	*)
		# single dependency
		parent=$(eval printf "\$exported_$deps")
		;;
	esac

	exported="$(msg "$1" |
		git stripspace |
		commitenv "$1" git commit-tree "$(pretty_tree "$1")" -p "$parent"
	)"
	eval "exported_$1=$exported"
}

## export_rev ## {{{2
export_rev() {
	local ref
	assert is_sha1 "$1"

	ref="$1"

	recurse_deps export_rev_cmd export_rev_chk "$ref"

	eval echo "\$exported_$ref"
}

## is_sha1 ## {{{2
is_sha1() {
	assert test "$#" = 1
	git rev-parse -q --verify "$1" >/dev/null &&
	test "$(git rev-parse --verify "$1")" = "$1"
}

## is_ugbase ## {{{2
is_base() {
	rev_has_file "$1" ".ubergit/deps"
}

## is_topic ## {{{2
is_topic() {
	rev_has_file "$1" ".ubergit/base"
}

## is_ugish ## {{{2
is_ugish() {
	rev_has_file "$1" ".ubergit/"
}

## msg ## {{{2
msg() {
	# XXX: encoding of msg file?  Assume encoding of commit?
	assert test "$#" = 1
	assert is_topic "$1"

	git cat-file blob "$1:.ubergit/msg"
}

## personfromcommit ## {{{2
# personfromcommit <commitish> [author|committer] [AUTHOR|COMMITTER]
personfromcommit() {
	# inspired by git's get_author_ident_from_commit
	local encoding script

	encoding="$(git config i18n.commitencoding || echo UTF-8)"
	script="
        /^$2 /{
                s/'/'\\\\''/g # quote single quotes
                h
                s/^$2 \\([^<]*\\) <[^>]*> .*$/GIT_$3_NAME='\\1'/p

                g
                s/^$2 [^<]* <\\([^>]*\\)> .*$/GIT_$3_EMAIL='\\1'/p

                g
                s/^$2 [^<]* <[^>]*> \\(.*\\)$/GIT_$3_DATE='\\1'/p

                q
        }
	/^\$/q
	"
	git show -s --pretty=raw --encoding="$encoding" "$1" -- | sed -n -e "$script"
}

## pretty_tree ## {{{2
pretty_tree() {
	git ls-tree --full-tree "$1" \
	| awk -F '	' '$2 != ".ubergit"' \
	| git mktree
}

## recurse_deps ## {{{2
## recurse_deps <cmd> <recchk> <commitish>
recurse_deps() {
	local recdep_cmd recdep_recchk recdep
	recdep_cmd="$1"; shift
	recdep_recchk="$1"; shift

	if is_topic "$1" && "$recdep_recchk" "$@"; then
		for recdep in $(deps "$1"); do
			debug "recurse: patch=$1, dep=$recdep"
			recurse_deps "$recdep_cmd" "$recdep_recchk" "$recdep" "$@" || return "$?"
		done
	fi

	"$recdep_cmd" "$@"
}

## rev_has_file ## {{{2
rev_has_file() {
	git ls-tree --full-tree --name-only "$1" "$2" | grep . > /dev/null
}

## rev_verify ## {{{2
rev_verify() {
	git rev-parse --verify -q "$1" >/dev/null
}

## sq ## {{{2
sq() {
	# depends on git >= v1.6.4-rc0~24^2~22
	git rev-parse --sq-quote "$@"
}

## option parsing ## {{{1
if test -n "$UG_OPTIONS_SPEC"; then
	eval "$(printf "%s\n" "$UG_OPTIONS_SPEC" | git rev-parse --parseopt --keep-dashdash --stop-at-non-option -- "$@" || echo "exit '$?'")"
fi