#!/bin/sh -e
#
# 2020 Dennis Camera (dennis.camera@ssrq-sds-fds.ch)
#
# This file is part of cdist.
#
# cdist is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# cdist is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with cdist. If not, see <http://www.gnu.org/licenses/>.
#

drop_awk_comments() { sed '/^[[:blank:]]*#.*$/d;/^$/d' "$@"; }

CONF_PATH=/etc/dma  # set in Makefile

# Determine mailname
if test -f "${__object:?}/parameter/mailname"
then
	mailname=$(cat "${__object:?}/parameter/mailname")
else
	case $(cat "${__global:?}/explorer/os")
	in
		(debian|devuan|ubuntu)
			# On Debian-like systems use /etc/mailname unless --mailname is used
			mailname='/etc/mailname'
			;;
		(*)
			mailname=${__target_fqdn:?}
			;;
	esac
fi


# Generate "should" values for config
conf_should=$(
	if test -s "${__object:?}/parameter/smarthost"
	then
		printf 'SMARTHOST %s\n' "$(cat "${__object:?}/parameter/smarthost")"
	fi

	printf 'MAILNAME %s\n' "${mailname}"

	if test -s "${__object:?}/explorer/auth_conf"
	then
		printf "AUTHPATH %s\n" "$(cat "${__object:?}/explorer/auth_conf")"
	fi

	case $(cat "${__object:?}/parameter/security")
	in
		(ssl|tls)
			default_smtp_port=465
			echo 'SECURETRANSFER'
			;;
		(starttls)
			default_smtp_port=587
			echo 'SECURETRANSFER'
			echo 'STARTTLS'
			;;
		(opportunistic)
			default_smtp_port=25
			echo 'SECURETRANSFER'
			echo 'STARTTLS'
			echo 'OPPORTUNISTIC_TLS'
			;;
		(insecure)
			default_smtp_port=25
			echo 'INSECURE'
			;;
	esac

	if test -s "${__object:?}/parameter/port"
	then
		printf 'PORT %u\n' "$(cat "${__object:?}/parameter/port")"
	elif test "${default_smtp_port}" -ne 25  # DMA uses port 25 by default
	then
		printf 'PORT %u\n' "${default_smtp_port}"
	fi

	if test -f "${__object:?}/parameter/masquerade"
	then
		while read -r line
		do
			printf 'MASQUERADE %s\n' "${line}"
		done <"${__object:?}/parameter/masquerade"
	fi

	if test -f "${__object:?}/parameter/defer"
	then
		echo 'DEFER'
	fi

	if test -f "${__object:?}/parameter/fullbounce"
	then
		echo 'FULLBOUNCE'
	fi

	if test -f "${__object:?}/parameter/nullclient"
	then
		test -s "${__object:?}/parameter/smarthost" || {
			echo '--nullclient requires a --smarthost to be defined' >&2
			exit 1
		}

		echo 'NULLCLIENT'
	fi
)
# Sort conf_should to compare against "conf_is"
conf_should=$(echo "${conf_should}" | sort -s -k 1,1)

config_updated=false
if ! echo "${conf_should}" | cmp -s "${__object:?}/explorer/conf" -
then
	# config needs to be updated
	dma_conf="${CONF_PATH:?}/dma.conf"

	# The following AWK script will output the new config file to be stored on
	# disk. To do so it reads the current dma.conf file and the config options
	# that should be set (from stdin).
	# Note that the path to the current dma.conf is passed to AWK twice, because
	# the new file cannot be generated in one pass.

	# The logic tries to place options at a sensible location, that is:
	# a) if the option is already used in the config file:
	#    group all similar options (e.g. MASQUERADE) at one place in the order
	#    they are listed in stdin.
	# b) if it is a new option and a "default comment" (e.g. "#PORT 25") exists:
	#    place options grouped directly after the comment (the comment is left
	#    alone)
	# c) otherwise:
	#    options are grouped by word (the first word in the line) and appended
	#    at the end of the file.

	cat <<CODE
awk '$(drop_awk_comments "${__type:?}/files/update_dma_conf.awk")' '${dma_conf}' '${dma_conf}' <<'EOF' >'${dma_conf}.tmp' \
&& cat '${dma_conf}.tmp' >'${dma_conf}'
${conf_should}
EOF
rm '${dma_conf}.tmp'
CODE

	config_updated=true
	echo 'config updated' >>"${__messages_out:?}"
fi


# Send a test email if enabled and necessary (=configuration changed)
if test -f "${__object:?}/parameter/send-test-mail"
then
	if grep -q '^__mail_alias/root:' "${__messages_in:?}" \
	|| grep -q '^__dma_auth/' "${__messages_in:?}" \
	|| $config_updated
	then
		cat <<-CODE
		sendmail root <<'EOF'
		Subject: [cdist] Test mail from '${__target_fqdn:?}'

		Hi,

		you can ignore this message.
		Its sole purpose is to notify you that root mail on ${__target_fqdn:?}
		will be redirected to you.

		Enjoy!
		EOF
		CODE
	fi
fi