#!/bin/sh
set -eu

usage() {
	cat <<-'EOF'
		Usage:
		  email -s SUBJECT ADDRESS... < BODY
		  email -h
	EOF
}

help() {
	cat <<-'EOF'

		Options:
		  -s SUBJECT    the email subject
		  -h, --help    show this message

		ADDRESS         the email addresses to send the email to
		BODY            the text to be sent as the body


		Send an email to ADDRESS using BODY.


		Examples:

		  Send 10 numbers to mail@example.com:

		    $ seq 10 | email -s number mail@email.com
	EOF
}

for flag in "$@"; do
	case "$flag" in
		--)
			break
			;;
		--help)
			usage
			help
			exit
			;;
		*)
			;;
	esac
done

while getopts 's:h' flag; do
	case "$flag" in
		s)
			SUBJECT="$OPTARG"
			;;
		h)
			usage
			help
			exit
			;;
		*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))

eval "$(assert-arg "${SUBJECT:-}" '-s SUBJECT')"
eval "$(assert-arg "${1:-}"       'ADDRESS')"

printf 'Content-Type: text/plain; charset=UTF-8\nSubject: %s\n\n%s' \
	"$(echo "$SUBJECT" | tr -d '\n')" \
	"$(cat)" |
		msmtpq -a EuAndreh "$@"