#!/bin/sh -eu
# analyze-packet-spam – show minetest client packet count per second
# Copyright © 2021  Nils Dagsson Moskopp (erlehmann)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.

# Dieses Programm hat das Ziel, die Medienkompetenz der Leser zu
# steigern. Gelegentlich packe ich sogar einen handfesten Buffer
# Overflow oder eine Format String Vulnerability zwischen die anderen
# Codezeilen und schreibe das auch nicht dran.

# This script takes a minetest log with at least INFO log level and
# outputs the MINETEST network protocol packet count per second.

# To collect such a log file of minetest running for 10 minutes, run:
# timeout 600 minetest --info >log.txt 2>&1 >/dev/null

# To get packet counts from that file, run:
# ./analyze-packet-spam <log.txt

TEMPFILE=$(mktemp /tmp/minetest.analyze-packet-spam.XXXXXXXX)

grep -F 'INFO[Main]: cmd' \
 |while read DATE TIME _ _ PACKET_ID PACKET_NAME _ PACKET_COUNT; do
  TIMESTAMP=$(date +%s --date "${DATE} ${TIME%:}")
  PACKET_NAME=${PACKET_NAME#(}
  PACKET_NAME=${PACKET_NAME%)}
  VARIABLE=PACKET_COUNT_"${PACKET_NAME}"
  eval "$( echo $VARIABLE=\$\(\( \${$VARIABLE:-0} + ${PACKET_COUNT} \)\) )"
  printf '%s ' \
   "${TIMESTAMP}" \
   "${VARIABLE}"
  eval echo \$${VARIABLE}
done >"${TEMPFILE}"

TIMESTAMP_START=$( <"${TEMPFILE}" head -n1 |cut -d' ' -f1 )
TIMESTAMP_END=$( <"${TEMPFILE}" tail -n1 |cut -d' ' -f1 )
DURATION=$(( 30 + ${TIMESTAMP_END} - ${TIMESTAMP_START} ))

PACKET_NAME_SEEN=''
<"${TEMPFILE}" tac \
 |while read _ PACKET_NAME PACKET_COUNT; do
  case "${PACKET_NAME_SEEN}" in
   *"${PACKET_NAME}"*)
   ;;
   *)
    PACKET_COUNT_PER_SECOND=$(
     printf '1k %s %s /p' "${PACKET_COUNT}" "${DURATION}" \
      |dc
    )
    printf '%s\t%s\n' "${PACKET_COUNT_PER_SECOND}" "${PACKET_NAME}"
    PACKET_NAME_SEEN="${PACKET_NAME_SEEN} ${PACKET_NAME}"
   ;;
  esac
 done

unlink "${TEMPFILE}"