#!/usr/bin/env bash

# Author        : Allan Christensen
# First Created : 17102020 (DD-MM-YYYY)
# Description   : Installs Postfix and optionally Mailutils on Ubuntu 24.04
# License       : MIT License (see LICENSE file for details)

#
# Are we root
#
if [[ $(id -u) -ne 0 ]]; then echo "" && echo "Must be root or use sudo" && echo "" ; exit ; fi

#
# Define variables and functions
#
install_utils="no"

#
# Function to check if a service is already running or not
#
serviceyes () { printf "\n%s" $service ; printf " is already running cannot continue...\n\n"; }
servicealive () { status=$(systemctl is-active $service); if [[ "$status" == "active" ]]; then serviceyes ; exit 1; fi; }

#
# Usage function
#
usage() {
    printf "\nUsage:\n"
    printf "  sudo ./postfixinstall [-m yes|no]\n\n"
    printf "Options:\n"
    printf "  -m <yes|no>   Install Mailutils (defaults to no)\n"
    printf "  -h            Show this help message\n\n"
    printf "Examples:\n"
    printf "  sudo ./postfixinstall        # install Postfix only\n"
    printf "  sudo ./postfixinstall -m yes # install Postfix + Mailutils\n\n"
    exit 1
}

#
# If Postfix is already running then die
#
service="postfix" ; servicealive

#
# Let's go
#
clear

#
# Parse options
#
while getopts ":m:h" opt; do
    case "${opt}" in
        m)
            arg="${OPTARG}"
            if [[ -z "$arg" ]]; then
                printf "\nOption -m requires an argument (yes/no).\n"
                usage
            fi
            case "${arg,,}" in
                y|yes) install_utils="yes" ;;
                n|no)  install_utils="no" ;;
                *) usage ;;
            esac
            ;;
        h)
            usage
            ;;
        :)
            printf "\nOption -%s requires an argument (yes/no).\n" "$OPTARG"
            usage
            ;;
        \?)
            printf "\nInvalid option: -%s\n" "$OPTARG"
            usage
            ;;
    esac
done

#
# Require -m flag
#
if [[ "$OPTIND" -eq 1 ]]; then
    printf "\nMissing required option: -m <yes|no>\n"
    usage
fi

#
# Install Postfix (non-interactive) and backup main.cf
#
printf "\nInstalling Postfix...\n"
DEBIAN_FRONTEND=noninteractive apt-get install -y postfix >/dev/null 2>&1
[[ -f /etc/postfix/main.cf ]] && cp -p /etc/postfix/main.cf /etc/postfix/main.cf.bak.$(date +%d-%m-%Y-%H%M%S)
systemctl enable postfix >/dev/null 2>&1 && systemctl restart postfix

#
# Optionally install Mailutils
#
if [[ "$install_utils" == "yes" ]]; then apt-get install -y mailutils >/dev/null 2>&1 ; fi

#
# All done
#
printf "\nAll Done...\n"

#
# End of script
#