#!/usr/bin/env bash
# Install and generate motd
# Copyright 2019-2025 Bryan C. Roessler
# Licensed under the Apache License, Version 2.0
set -euo pipefail

PROG_NAME="$(basename "$0")"
INSTALL_PATH="/usr/local/bin/$PROG_NAME"
SERVICE_UNIT="/usr/lib/systemd/system/motd.service"
TIMER_UNIT="/usr/lib/systemd/system/motd.timer"

usage() {
  cat <<-EOF
		Usage: $PROG_NAME [--motd | --install] [--help]

		Options:
		  --motd       Output MOTD to stdout (used by systemd)
		  --install    Instal motd systemd service and timer
		  -h, --help   Show this help message
EOF
}

print_motd() {
  # ANSI color codes
  local default='\033[0m' green='\033[0;32m' red='\033[0;31m'
  local dim='\033[2m' undim='\033[22m'

  cat <<-'EOF'
		 _    _            _                           _           _     
		| |  | |          | |                         | |         | |    
		| |__| | __ _ _ __| |_ _ __ ___   __ _ _ __   | |     __ _| |__  
		|  __  |/ _` | `__| __| `_ ` _ \ / _` | `_ \  | |    / _` | `_ \ 
		| |  | | (_| | |  | |_| | | | | | (_| | | | | | |___| (_| | |_) |
		|_|  |_|\__,_|_|   \__|_| |_| |_|\__,_|_| |_| |______\__,_|_.__/ 
	EOF

  # System info
  read -r LOAD1 LOAD5 LOAD15 < <(awk '{print $1, $2, $3}' /proc/loadavg)
  read -r USED AVAIL TOTAL < <(free -htm | awk '/^Mem:/ {print $3, $7, $2}')

  local ROOT_PROCS NONROOT_PROCS TOTAL_PROCS
  ROOT_PROCS=$(pgrep -u root | wc -l)
  NONROOT_PROCS=$(( $(ps -eo user= | wc -l) - ROOT_PROCS ))
  TOTAL_PROCS=$(( ROOT_PROCS + NONROOT_PROCS ))

  local CPU_MODEL CPU_COUNT
  CPU_MODEL=$(awk -F': ' '/model name/ {print $2; exit}' /proc/cpuinfo)
  CPU_COUNT=$(grep -c '^processor' /proc/cpuinfo)

  . /etc/os-release
  local DISTRO="$PRETTY_NAME"
  local KERNEL; KERNEL="$(uname -sr)"
  local UPTIME; UPTIME="$(uptime -p)"

  # Load
  printf "\n"
  printf "  Distro......: %s\n" "$DISTRO"
  printf "  Kernel......: %s\n" "$KERNEL"
  printf "  Uptime......: %s\n" "$UPTIME"
  printf "  Load........: %b%s%b (1m), %b%s%b (5m), %b%s%b (15m)\n" \
    "$green" "$LOAD1" "$default" \
    "$green" "$LOAD5" "$default" \
    "$green" "$LOAD15" "$default"
  printf "  Processes...: %b%d%b (root), %b%d%b (user), %b%d%b (total)\n" \
    "$green" "$ROOT_PROCS" "$default" \
    "$green" "$NONROOT_PROCS" "$default" \
    "$green" "$TOTAL_PROCS" "$default"
  printf "  CPU.........: %s (%b%d%b vCPU)\n" \
    "$CPU_MODEL" "$green" "$CPU_COUNT" "$default"
  printf "  Memory......: %b%s%b used, %b%s%b avail, %b%s%b total\n" \
    "$green" "$USED" "$default" \
    "$green" "$AVAIL" "$default" \
    "$green" "$TOTAL" "$default"

  # Disks
  echo -e "\n  Disk usage"
  local max_usage=90 bar_width=50
  while read -r target pcent size; do
    local use=${pcent%\%}
    local filled=$(( use * bar_width / 100 ))
    local bar="["

    local col=$green
    (( use >= max_usage )) && col=$red

    bar+="$col"
    for ((i=0;i<filled;i++)); do bar+="="; done
    bar+="$default$dim"
    for ((i=filled;i<bar_width;i++)); do bar+="="; done
    bar+="$undim]"

    printf "    %-25s %3s of %-6s\n" "$target" "$pcent" "$size"
    printf "    %b\n" "$bar"
  done < <(
    df -H -x zfs -x squashfs -x tmpfs -x devtmpfs -x overlay \
      --output=target,pcent,size | tail -n +2
  )

  # Services
  echo -e "\n  Services"
  local services=(
    btrfs-balance.timer btrfs-scrub.timer backup.timer btrbk.timer fstrim.timer
    fail2ban firewalld smb nmb motion smartd cockpit.socket
    dnf-automatic.timer motd.timer
  )
  for ((i=0; i<${#services[@]}; i+=2)); do
    local s1=${services[i]} s2=${services[i+1]:-}
    local st1 st2 c1 c2
    st1=$(systemctl is-active "$s1" 2>/dev/null || echo inactive)
    st2=$(systemctl is-active "$s2" 2>/dev/null || echo inactive)
    [[ $st1 == active ]] && c1="${green}$st1${default}" || c1="${red}$st1${default}"
    [[ $st2 == active ]] && c2="${green}$st2${default}" || c2="${red}$st2${default}"
    printf "    %-15s : %b    %-15s : %b\n" \
      "${s1%.*}" "$c1" "${s2%.*}" "$c2"
  done

	# Fail2Ban
	read -r -a jails <<< "$(fail2ban-client status | grep "Jail list:" | sed "s/ //g" | awk '{split($2,a,",");for(i in a) print a[i]}')"

	out="jail,failed,total,banned,total\n"

	for jail in "${jails[@]}"; do
		# Slow because fail2ban-client has to be called for every jail (~70ms per jail)
		status=$(fail2ban-client status "$jail")
		failed=$(echo "$status" | grep -ioP '(?<=Currently failed:\t)[[:digit:]]+')
		totalfailed=$(echo "$status" | grep -ioP '(?<=Total failed:\t)[[:digit:]]+')
		banned=$(echo "$status" | grep -ioP '(?<=Currently banned:\t)[[:digit:]]+')
		totalbanned=$(echo "$status" | grep -ioP '(?<=Total banned:\t)[[:digit:]]+')
		out+="$jail,$failed,$totalfailed,$banned,$totalbanned\n"
	done

	printf "\nFail2ban\n"
	printf "%b\n" "$out" | column -ts $',' | sed -e 's/^/  /'

  # Help links
  cat <<-EOF

		Links (ctrl+click to follow)
		  Server Manual.........: https://tinyurl.com/jjz9h6fr
		  Cockpit (for admins)..: http://localhost:9090
		  Robot Camera..........: http://localhost:9999
		  JupyterLab............: http://localhost:8888
		  RStudio Server........: http://localhost:8787
		  Robot Computer........: vnc://192.168.16.101:5900
		  Windows 10 VM.........: vnc://localhost:5900 (pw: hartman)
	EOF

	# Scheduled reboot
	if systemctl is-active scheduled-reboot.timer &>/dev/null; then
		echo -n "Next scheduled reboot: "
		time=$(systemctl cat scheduled-reboot.timer | grep OnCalendar=)
		time=${time#*=}
		echo "$time"
	fi

  if systemctl is-active scheduled-reboot.timer &>/dev/null; then
    echo -n "  Next reboot  : "
    systemctl show -p OnCalendar scheduled-reboot.timer | cut -d= -f2
  fi

  printf "\n"
}

install_services() {
  # Write the service unit
  cat >"$SERVICE_UNIT" <<-EOF
		[Unit]
		Description=Generate MoTD

		[Service]
		Type=oneshot
		ExecStart=$INSTALL_PATH --motd > /etc/motd

		[Install]
		WantedBy=multi-user.target
	EOF

  # Write the timer unit
  cat >"$TIMER_UNIT" <<-EOF
		[Unit]
		Description=Generate MoTD every minute

		[Timer]
		OnCalendar=*:0/1
		OnBootSec=10s

		[Install]
		WantedBy=timers.target
	EOF

  chmod +x "$INSTALL_PATH"
  systemctl daemon-reload
  systemctl enable --now motd.timer
  echo "Installed and started motd.timer → $SERVICE_UNIT, $TIMER_UNIT"
}

main() {
  if [[ ${1:-} == --motd ]]; then
    print_motd
    exit 0
  fi

  if [[ ${1:-} == --install ]]; then
    if [[ $EUID -ne 0 ]]; then
      echo "Error: Must run as root to install." >&2
      exit 1
    fi
    cp -f "$0" "$INSTALL_PATH"
    install_services
  fi

  if [[ ${1:-} =~ ^(-h|--help)$ ]]; then
    usage
    exit 0
  fi


}

main "$@"