#!/bin/bash

# kf2-srv is a command line tool for managing a set of Killing Floor 2 servers.
# Copyright (C) 2019, 2020 GenZmeY
# mailto: genzmey@gmail.com
# 
# This file is part of kf2-srv.
#
# kf2-srv is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# conversion algorithm taken from here:
# https://github.com/noobient/killinuxfloor/blob/master/share/killinuxfloor
# thank bviktor for that :)
function steamID3_to_steamID64 () # $1: ID3
{
    # steamID64 = "7656" + (steamID3 + 1197960265728)
    ID64=$1
    ((ID64+=1197960265728))
    ID64="7656${ID64}"
    echo "$ID64"
}

function steamID64_to_steamID3 () # $1: ID4
{
    # steamID3 = substr(steamID64, 4) - 1197960265728
    ID3=${1:4}
    ((ID3-=1197960265728))
    echo "$ID3"
}

function any_to_ID3 () # $1: ID3/ID64/Url
{
	if echo "$1" | grep -qP '^http.+'; then
		local Xml=$(mktemp)
		curl -ss "$1/?xml=1" > "$Xml"
		local ID64=$(xmllint --xpath 'string(//steamID64/text())' "$Xml")
		local ID3=$(steamID64_to_steamID3 "$ID64") 
		rm -f "$Xml"
	elif [[ $(echo "$1" | wc -m) -eq 18 ]] && echo "$1" | grep -qP '^76561[0-9]+' ; then
		local ID3=$(steamID64_to_steamID3 "$1")
	else
		local ID3="$1"
	fi
	echo "$ID3"
}