#!/bin/sh

# abuild-keygen - generate signing keys
# Copyright (c) 2009 Natanael Copa <ncopa@alpinelinux.org>
#
# Distributed under GPL-2.0-only
#

program_version=@VERSION@
sharedir=${ABUILD_SHAREDIR:-@sharedir@}
SUDO="${SUDO:-sudo}"

if ! [ -f "$sharedir/functions.sh" ]; then
	echo "$sharedir/functions.sh: not found" >&2
	exit 1
fi
. "$sharedir/functions.sh"

set -e

# ask for privkey unless non-interactive mode
# returns value in global $privkey
get_privkey_file() {
	local emailaddr default_name
	emailaddr=${PACKAGER##*<}
	emailaddr=${emailaddr%%>*}

	# if PACKAGER does not contain a valid email address, then ask git
	if [ -z "$emailaddr" ] || [ "${emailaddr##*@}" = "$emailaddr" ]; then
		emailaddr=$(git config --get user.email 2>/dev/null)
	fi

	default_name="${emailaddr:-$USER}-$(printf "%x" $(date +%s))"

	privkey="$ABUILD_USERDIR/$default_name.rsa"
	if [ -n "$non_interactive" ]; then
		return 0
	fi
	msg "Generating public/private rsa key pair for abuild"
	echo -n "Enter file in which to save the key [$privkey]: "

	read line
	if [ -n "$line" ]; then
		privkey="$line"
	fi
}

do_keygen() {
	mkdir -p "$ABUILD_USERDIR"

	get_privkey_file
	pubkey="$privkey.pub"

	# generate the private key in a subshell with stricter umask
	(
	umask 0007
	openssl genrsa -out "$privkey" "$numbits"
	)
	openssl rsa -in "$privkey" -pubout -out "$pubkey"

	if [ -n "$install_pubkey" ]; then
		msg "Installing $pubkey to /etc/apk/keys..."
		$SUDO mkdir -p /etc/apk/keys
		$SUDO cp -i "$pubkey" /etc/apk/keys/
	else

		msg ""
		msg "You'll need to install $pubkey into "
		msg "/etc/apk/keys to be able to install packages and repositories signed with"
		msg "$privkey"
	fi

	if [ -n "$append_config" ]; then
		if [ -f "$ABUILD_USERCONF" ]; then
			# comment out the existing values
			sed -i -e 's/^PACKAGER_PRIVKEY=/\#&/' "$ABUILD_USERCONF"
		fi
		echo "PACKAGER_PRIVKEY=\"$privkey\"" >> "$ABUILD_USERCONF"
	else
		msg ""
		msg "You might want add following line to $ABUILD_USERCONF:"
		msg ""
		msg "PACKAGER_PRIVKEY=\"$privkey\""
		msg ""
	fi

	msg ""
	msg "Please remember to make a safe backup of your private key:"
	msg "$privkey"
	msg ""
}

usage() {
	cat >&2 <<-__EOF__
		$program $program_version - generate signing keys
		Usage: $program [-a|--append] [-i|--install] [-n]
		Options:
		  -a, --append         Set PACKAGER_PRIVKEY=<generated key> in
		                       $ABUILD_USERCONF

		  -i, --install        Install public key into /etc/apk/keys using sudo
		  -n                   Non-interactive. Use defaults
		  -b, --numbits [BITS] The size of the private key to generate in bits.
		  -q, --quiet
		  -h, --help           Show this help

		The SUDO variable can be set to pick which tool can be used to
		elevate privileges, if it is not set it defaults to sudo.

	__EOF__
}

append_config=
install_pubkey=
non_interactive=
numbits=2048
quiet=

args=$(getopt -o ab:inqh --long append,numbits:,install,quiet,help -n "$program" -- "$@")
if [ $? -ne 0 ]; then
	usage
	exit 2
fi
eval set -- "$args"
while true; do
	case $1 in
		-a|--append) append_config=1;;
		-i|--install) install_pubkey=1;;
		-n) non_interactive=1;;
		-b|--numbits) numbits="$2"; shift 1;;
		-q|--quiet) quiet=1;; # suppresses msg
		-h|--help) usage; exit;;
		--) shift; break;;
		*) exit 1;; # getopt error
	esac
	shift
done
if [ $# -ne 0 ]; then
	usage
	exit 2
fi

do_keygen