#!/bin/sh
#
# gitinitremote
# turns a local directory into a new remote git repository,
# with the local directory being a clone of the remote
#
# e.g. gitinitremote ssh://mikelward.com/home/mikelward/git/uni/520/nimsys.git
#
# Mikel Ward <mikel@mikelward.com>

scriptname=gitinitremote

die()
{
	error "$*"
	exit 1
}

error()
{
	echo "$scriptname: $*" 1>&2
}

notice()
{
	echo "$scriptname: $*" 1>&2
}

warn()
{
	echo "$scriptname: $*" 1>&2
}

run()
{
	if $simulate; then
		echo "Would run $*" 1>&2
	else
		"$@"
	fi
}

usage()
{
	cat <<EOF 1>&2
Usage: $scriptname [-hn] [-r <remote name>] <new remote URL>
EOF
}

# defaults
remotename=origin	# what to call the remote
refspec=master		# refspec ("branch") to push - can't be changed yet
local=$PWD			# local directory to create the repository out of
simulate=false

while getopts ":hnr:" option
do
	case $option in
	h)
		usage
		exit 0
		;;
	n)
		simulate=true
		;;
	r)
		remotename=$OPTARG
		;;
	':')
		error "Missing argument to -$option"
		usage
		exit 2
		;;
	'?')
		error "Invalid option -$OPTARG"
		usage
		exit 2
		;;
	*)
		error "Program does not support -$option yet"
		usage
		exit 2
		;;
	esac
done
shift $((OPTIND - 1))

remote=$1

if test -z "$remote"; then
	error "Remote URL is required"
	usage
	exit 2
fi

case $remote in
ssh:*)
	remoteproto=ssh

	case $remote in
	*.git)
		:
		;;
	*)
		warn "Adding .git to end of remote URL"
		remote="$remote".git
		;;
	esac

	badformatmessage="SSH remote is not in the expected ssh://hostname/dir format"

	remotenoproto=${remote#ssh://}
	test "$remotenoproto" = "$remote" && die "$badformatmessage"

	remotehost=${remotenoproto%%/*}
	test "$remotehost" = "$remotenoproto" && die "$badformatmessage"

	remotedir=${remotenoproto#*/}
	test "$remotedir" = "$remotenoproto" && die "$badformatmessage"
	test -z "$remotedir" || test "$remotedir" = ".git" && die "$badformatmessage"	# don't allow root directory
	remotedir=/"$remotedir"		# re-add the leading slash that was stripped above
	;;
*)
	die "only ssh remotes are supported at the moment"
	;;
esac

test "$local" = "$PWD" || die "must currently be run from the local git directory"

if git status >/dev/null 2>&1; then
    localalreadyrepo=true
else
    localalreadyrepo=false
fi

if ! $localalreadyrepo; then
    run git init --quiet
fi

case $remoteproto in
ssh)
	ssh $remotehost true || die "Cannot connect to $remotehost via ssh"
	ssh $remotehost test -d "'$remotedir'" && die "$remotedir already exists on $remotehost"
	ssh $remotehost git --help >/dev/null 2>&1 || die "git is not installed on $remotehost"
	run ssh $remotehost git init --quiet --bare "'$remotedir'" || die "Cannot initialize remote repository"
	# git remote does not accept --quiet option
	run git remote add "$remotename" "$remote" || die "git remote add failed"
	;;
*)
	die "only ssh remotes are supported at the moment"
	;;
esac

if ! $localalreadyrepo; then
    # git <= 1.7 requires we have a non-empty directory for commit to work
    # (avoid "error: pathspec '' did not match any file(s) known to git.")
    dummyfile="$local/.gitignore"
    if ! test -f "$dummyfile"; then
        run touch "$dummyfile"
    fi
    # git add does not accept --quiet option
    run git add "$local"                                                            || die "git add failed"
    run git commit --quiet --message "Initial commit" "$local"                      || die "git commit failed"
fi

# git push does not accept --quiet option
run git push "$remotename" "$refspec"                                           || die "git push failed"

notice "Successfully created remote $remote as $remotename"

exit 0