#!/bin/sh -e

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  # XXX: correct?
			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
	echo "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 <<'EOF'
awk -F '\n' '
function comment_line(line) {
	# returns the position in line at which the comment'\''s text starts
	# (0 if the line is not a comment)
	match(line, /^[ \t]*\#+[ \t]*/)
	return RSTART ? (RLENGTH + 1) : 0
}
function empty_line(line) { return line ~ /^[ \t]*$/ }
function is_word(s) { return s ~ /^[A-Z_]+$/ }  # "looks like a plausible word"

function first(line, sep_re) {
	# returns the part of the line until sep is found
	# (or the whole line if sep is not found)
	if (!sep_re) sep_re = "[" SUBSEP "]"
	match(line, sep_re)
	return RSTART ? substr(line, 1, RSTART - 1) : line
}

function rest(line, sep_re) {
	# returns the part of the line after the first occurrence of sep is found.
	# (or nothing if sep is not found)
	if (!sep_re) sep_re = "[" SUBSEP "]"
	if (match(line, sep_re))
		return substr(line, RSTART + RLENGTH)
}

function conf_pop(word, value) {
	# returns the next value for the config `word` and delete it from the list.
	# if value is set, this function will only return value if it is the first
	# option in the list, otherwise it returns 0.

	if (!(word in conf)) return 0
	if (!value) {
		if (index(conf[word], SUBSEP))  # more than one element?
			value = substr(conf[word], 1, index(conf[word], SUBSEP) - 1)
		else
			value = conf[word]
	}

	if (index(conf[word], SUBSEP)) {
		if (index(conf[word], value SUBSEP) != 1) return 0
		conf[word] = substr(conf[word], length(value) + 2)
	} else {
		if (conf[word] != value) return 0
		delete conf[word]
	}
	return value
}

function print_conf(word, value) {
	# print a config line with the given parameters
	printf "%s", word
	if (value) printf " %s", value
	printf "\n"
}

function print_confs(word,    value) {
	# print config lines for all values stored in conf[word].
	if (!(word in conf)) return
	if (conf[word]) {
		while (value = conf_pop(word))
			print_conf(word, value)
	} else {
		print_conf(word)
		delete conf[word]
	}
}

BEGIN {
	EQS = "[ \t]"  # copied from dma/conf.c

	# read the "should" state into the `conf` array.
	while (getline < "/dev/stdin") {
		word = first($0, EQS)
		if ((word in conf))
			conf[word] = conf[word] SUBSEP rest($0, EQS)
		else
			conf[word] = rest($0, EQS)
	}
}

# first pass, gather information about where which information is stored in the
# current config file. This information will be used in the second pass.
NR == FNR {
	if (comment_line($0)) {
		# comment line
		word = first(substr($0, comment_line($0)), " ")
		if (is_word(word)) last_occ["#" word] = FNR
	} else {
		word = first($0, EQS)
		if (is_word(word)) last_occ[word] = FNR
	}
}

# before second pass prepare hashes containing location information to be used
# in the second pass.
NR > FNR && FNR == 1 {
	# First we drop the locations of commented-out options if a non-commented
	# option is available. If a non-commented option is available, we will
	# append new config options there to have them all at one place.
	for (k in last_occ)
		if (k ~ /^\#/ && (substr(k, 2) in last_occ))
			delete last_occ[k]

	# Reverse the option => line mapping. The line_map allows for easier lookups
	# in the second pass.
	for (k in last_occ) line_map[last_occ[k]] = k
}

# second pass, generate and output new config
NR > FNR {
	if (comment_line($0) || empty_line($0)) {
		# comment or empty line
		print

		if ((FNR in line_map)) {
			if (line_map[FNR] ~ /^\#/) {
				# This line contains a commented config option. If the conf hash
				# contains options to be set, we output them here because this
				# option is not used in the current config.
				k = substr(line_map[FNR], 2)
				if ((k in conf)) print_confs(k)
			}

			if (("INSECURE" in conf) && line_map[FNR] ~ /^\#?SECURE$/) {
				# INSECURE goes where SECURE comment is.
				print_confs("INSECURE")
			}
		}
	} else {
		word = first($0, EQS)
		value = rest($0, EQS)
		sub(/[ \t]*\#.*$/, "", value)  # ignore comments in value

		if ((word in conf) && value == first(conf[word])) {
			# keep config options we want
			conf_pop(word)
			print
		}

		if ((FNR in line_map) && line_map[FNR] == word) {
			# rest of config options should be here
			print_confs(word)
		}
	}
}

END {
	# print rest of config options (
	for (word in conf) print_confs(word)
}
' "${dma_conf}" "${dma_conf}" <<'EOF' >"${dma_conf}.tmp" \
 && mv "${dma_conf}.tmp" "${dma_conf}"
EOF
	# Pass in "conf_should" via stdin
	echo "${conf_should}"
	echo 'EOF'

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


if test -f "${__object}/parameter/send-test-email"
then
	if grep -q '^__mail_alias/root:' "${__messages_in}" \
	|| grep -q '^__dma_auth/' "${__messages_in}" \
	|| $config_updated
	then
		cat <<-EOF
		sendmail root <<EOM
		Subject: [cdist] Test mail from '${__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!
		EOM
		EOF
	fi
fi