#!/bin/bash


# Use ssmtp to send an email message


if [ $# -eq 0 ]; then
	echo "sendmsg: Usage sendmsg [ options [ optArg ] | recipientAddress ] ..." >&2
	exit 1
fi


# Tabs here:
# sendmsg: Usage sendmsg [ options [ optArg ] | recipientAddress ] ...
# Options:
#	-s subjectString		# Establish the message's subject header
#	-t recipientAddrress	# Add a primary recipient
#	-c ccAddress			# Add a carbon-copy recipient
#	-b blindCCAddress
#	-bc blindCCAddress
#	-bcc blindCCAddress		# Add a blind carbon-copy recipient
#	-m messageBodyFile		# Specify a file containing message content
#							#	May be repeated. A single hyphen causes
#							#	the standard input to be be read
#	-f senderAddress		# Establish the sender's (from) address
#	-fn senderFullName
#	-F senderFullName		# Establish the sender's full name
#	-r replyToAddress
#	-rt replyToAddress		# Establish a "Reply-To:" header
#	-nd
#	-nt						# Do not add a \"Date:\" header field
#	-d dateString			# Specify the contents of the \"Date:\" header
#							#	Note: Do not include the \"Date: portion\"
#	-ppp					# Re-create /etc/ssmtp/ssmtp.conf
#	-q queueFile			# Enqueue message in specified queue file
#	-pq queueFile			# Print headers of mail queued in specified queue file
#	-sq queueFile			# Send mail queued in specified queue file
#							#	based on current PPP connection
#	-h | -help | --help		# Show this usage summary


# Spaces here:
usageSummary="# sendmsg: Usage sendmsg [ options [ optArg ] | recipientAddress ] ...
# Options:
#   -s subjectString        # Establish the message's subject header
#   -t recipientAddrress    # Add a primary recipient
#   -c ccAddress            # Add a carbon-copy recipient
#   -b blindCCAddress
#   -bc blindCCAddress
#   -bcc blindCCAddress     # Add a blind carbon-copy recipient
#   -m messageBodyFile      # Specify a file containing message content
#                           #   May be repeated. A single hyphen causes
#                           #   the standard input to be be read
#   -fn senderFullName
#   -F senderFullName       # Establish the sender's full name
#   -r replyToAddress
#   -rt replyToAddress      # Establish a "Reply-To:" header
#   -nd
#   -nt                     # Do not add a \"Date:\" header field
#   -d dateString           # Specify the contents of the \"Date:\" header
#                           #   Note: Do not include the \"Date: portion\"
#   -ppp                    # Re-create /etc/ssmtp/ssmtp.conf
#   -q queueFile            # Enqueue message in specified queue file
#   -pq queueFile           # Print headers of mail queued in specified queue file
#   -sq queueFile           # Send mail queued in specified queue file
#                           #   based on current PPP connection
#   -h | -help | --help     # Show this usage summary
"

showUsage() {
	echo "$usageSummary"
}



# Extract an option argument from the script's positional parameters
#	Note: unfinished and wrong...
optArg() {
	if [ $# -lt 1 ]; then
		echo "sendmsg: \"$1\" option requires an argument" 2>&1
		quitEarly=1
	else
		eval "$2=$1"
		shift
	fi
}



# Perl-like join operator
join() {
	out=
	sep="$1"

	shift

	for elt; do
		[ -z "$out" ] && out="$elt" || out="$out$sep$elt"
	done

	echo -n "$out"
}


quoteAll() {
	quoteChar=$1
	shift

	for elt
		do echo -n "$quoteChar${elt//$quoteChar/\\$quoteChar/}$quoteChar "
	done
}



declare -a recipients
declare -a carbons
declare -a blindCarbons
declare -a bodyFiles
declare -a fromArgs

noTimeStamp=
timeStamp="$(date +'%a, %d %b %Y %T %z')"

fromAddr=
fromName=
replyToAddr=

doPPPConfig=
messageQueueFile=
sendQueueFile=
printQueueFile=

quitEarly=


# Append entries to the array whose name is the first argument
appenda() {
	aName="$1"
	shift
	for aSlot; do
		appendCmd="$aName[\${#$aName[@]}]=\"$aSlot\""
		eval "$appendCmd"
	done
}



while [ $# -gt 0 ]; do

	arg="$1"
	nextArg="$2"

	shift

	case "$arg" in

	-s)
		# Subject
		subject="$nextArg"
		shift
		;;

	-t)
		# Primary recipient
		appenda recipients "$nextArg"
		shift
		;;

	-c | -cc)
		# Carbon copy recipient
		appenda carbons "$nextArg"
		shift
		;;

	-b | -bc | -bcc)
		# Blind carbon copy recipient
		appenda blindCarbons "$nextArg"
		shift
		;;

	-m)
		# Message body file
		appenda bodyFiles "$nextArg"
		shift
		;;

	-f)
		# Sender (From:) address
		fromAddr="$nextArg"
		shift
		;;

	-F | -fn)
		# Sender (From:) name
		fromName="$nextArg"
		shift
		;;

	-r | -rt)
		# Reply-To address
		replyToAddr="$nextArg"
		shift
		;;

	-nt | -nd)
		# Inhibit "Date:" header
		noTimestamp=1
		;;

	-d)
		# Specify time-stamp value
		timeStamp="$nextArg"
		shift
		;;

	-q)
		# Enqueue the message for later sending
		messageQueueFile="$nextArg"
		shift
		;;

	-sq)
		# Send queued messages
		sendQueueFile="$nextArg"
		shift
		;;

	-pq)
		# List queued messages
		printQueueFile="$nextArg"
		shift
		;;

	-ppp)
		# Run smtp-ppp-config before sending
		doPPPConfig=1
		;;

	-h | -help | --help)
		# Provide usage summary
		showUsage
		quitEarly=0
		;;

	-*)
		echo "sendmsg: Unrecognized option \"$arg\" (\"sendmsg --help\" for usage summary)" >&2
		quitEarly=1
		;;

	*)
		# Other arguments are assumed to be primary recipient addresses
		appenda recipients "$arg"
		;;
	esac
done


# Stop now?
if [ "$quitEarly" ]; then
	exit $quitEarly
fi


# Configure for PPP link?
if [ "$doPPPConfig" -a -n "$messageQueueFile" ]; then
	if ssmtp-ppp-config; then
		:
	else
		echo "sendmsg: Unable to configure email for PPP"
	fi
fi


# Quit now if there is nothing left to do
if [ ${#recipients[@]} -eq 0 -a ${#carbons[@]} -eq 0 -a ${#blindCarbons[@]} -eq 0 \
	 -a -z "$printQueueFile" -a -z "$sendQueueFile" ]; then
	echo "sendmsg: No-op"
	exit 0
fi


# Prepare "From:" options for ssmtp
if [ -n "$fromAddr" -o -n "$fromName" ]; then
	if [ -n "$messageQueueFile" ]; then
		fromArgs=("\"-f$fromAddr\"" "\"-F$fromName\"")
	else
		fromArgs=("-f$fromAddr" "-F$fromName")
	fi
fi


# Synthesize the message
if [ ${#recipients[@]} -gt 0 -o ${#carbons[@]} -gt 0 -o ${#blindCarbons[@]} -gt 0 ]; then
	(
		# Synthesize header fields

		if [ ! "$noTimeStamp" ]; then
			echo "Date: $timeStamp"
		fi

	#	if [ -n "$fromAddr" ]; then
	#		if [ -n "$fromName" ]; then
	#			echo "From: ${echo "$fromName" |tr -d "!@#$%^&*()+={}[]:;\"'<>,.?/"} <$fromAddr>"
	#		else
	#			echo "From: $fromAddr"
	#		fi
	#	fi

		if [ -n "$replyToAddr" ]; then
			echo "Reply-To: $replyToAddr"
		fi

		if [ -n "$subject" ]; then
			echo "Subject: $subject"
		fi

		if [ ${#recipients[@]} -gt 0 ]; then
			echo "To: $(join ", " "${recipients[@]}")"
		fi

		if [ ${#carbons[@]} -gt 0 ]; then
			echo "CC: $(join ", " "${carbons[@]}")"
		fi

		if [ ${#blindCarbons[@]} -gt 0 ]; then
			for bccRecipient in "${blindCarbons[@]}"; do
				echo "BCC: $bccRecipient"
			done
		fi

		echo

		# Generate and / or collect (from standard input) the body of the message
		cat "${bodyFiles[@]}"
	) | (
		# Queue for later or send now?

		if [ -n "$messageQueueFile" ]; then
			# Queue the message for later
			eomTag="EOM_$(date +'%Y%m%d%H%M%S')"
			(	echo "ssmtp $(quoteAll \" "${fromArgs[@]}" "${recipients[@]}" "${carbons[@]}" "${blindCarbons[@]}") <<$eomTag"
				cat
				echo "$eomTag"$'\n\n'
			)>>"$messageQueueFile"

		else
			# Send the message on its way:
			ssmtp "${fromArgs[@]}" "${recipients[@]}" "${carbons[@]}" "${blindCarbons[@]}"
		fi
	)
fi


# List queued messages
if [ -n "$printQueueFile" ]; then
	if [ -s "$printQueueFile" ]; then
		sed -n -e '/^ssmtp/,/^$/p' "$printQueueFile" |egrep -v '^ssmtp'
	else
		echo "sendmsg: No messages are currently queued in \"$printQueueFile\""
	fi
fi


# Send queued messages
if [ -n "$sendQueueFile" -a -s "$sendQueueFile" ]; then

	# Configure for PPP link?
	if [ "$doPPPConfig" -a -n "$messageQueueFile" ]; then
		if ssmtp-ppp-config; then
			:
		else
			echo "sendmsg: Unable to configure ssmtp for PPP"
		fi
	fi

	source "$sendQueueFile"

	# Rename the file with a timestamp of the time it was sent
	mv "$sendQueueFile" "$sendQueueFile-$(date +'%Y-%m-%d@%H-%M-%S')"
fi