#!/usr/bin/bash

# check for nmap and jq
# check for root

starttime="$(date '+%Y-%m-%d %H:%M:%S')"

if [ -f arpscan.json ]
then
    #tempjson=$(jq '.ips += {} | .ips = ([ .ips | to_entries[] | select(.value.reserved == true) ] | from_entries)' arpscan.json)
    tempjson=$(jq '.ips += {} | .ips=(.ips|to_entries|map_values(.value.online=false)|from_entries)' arpscan.json)
    #tempjson="$(cat arpscan.json)"
    if [ $? -ne 0 ]
    then
        echo "Failed to load network JSON" 1>&2
        exit 1
    fi
else
    exit 1
fi

jsonescape() {
    jq -Rs . < <(printf "%s" "${1}")
}

foundhost() {
    tempjson=$(jq "$(jsonescape "${1}") as \$ip|.ips[\$ip].mac=$(jsonescape "${2}")|.ips[\$ip].online=true" <<< "${tempjson}")
}

doscan() {
    local nmaplog
    nmaplog=$(sudo nmap -sn -n 192.168.16.0/24)
    if [ $? -ne 0 ]
    then
        echo "nmap failed" 1>&2
        return 1
    fi
    cat <<< "${nmaplog}" > nmaplog.txt

    local parsestep
    local ipaddr
    parsestep=waitheader
    ipaddr=

    while read -r line
    do
        case $parsestep in
            waitheader)
                if [[ "${line}" != "Starting Nmap "* ]]
                then
                    echo "Nmap start header expected, got ${line}" 1>&2
                    return 1
                fi
                parsestep=hostdata
                ;;
            hostdata)
                if [[ "${line}" == "Nmap done: "* ]]
                then
                    parsestep=scandone
                elif [[ "${line}" =~ ^Nmap\ scan\ report\ for\ (.*)$ ]]
                then
                    ipaddr="${BASH_REMATCH[1]}"
                elif [[ "${line}" =~ ^Host\ is\ up(\ \(.*\))?.$ ]]
                then
                    continue
                elif [[ "${line}" =~ ^MAC\ Address:\ ([A-F0-9:]{17}).*$ ]]
                then
                    local macaddr
                    macaddr="${BASH_REMATCH[1]}"
                    if [[ "${ipaddr}" == "" ]]
                    then
                        echo "Found MAC without IP" 1>&2
                        return 1
                    fi
                    foundhost "${ipaddr}" "${macaddr}"
                    if [ $? -ne 0 ]
                    then
                        echo "Registering host failed" 1>&2
                        return 1
                    fi
                    ipaddr=
                else
                    echo "Failed to parse: ${line}" 1>&2
                    return 1
                fi
                ;;
            scandone)
                echo "Unexpected data after scan: ${line}" 1>&2
                return 1
                ;;
            *)
                echo "Invalid parse step: ${parsestep}" 1>&2
                return 1
                ;;
        esac
    done <<< "$nmaplog"
    #done < nmaplog.txt
}

doscan
if [ $? -ne 0 ]
then
    echo "Scan failed" 1>&2
    exit 1
fi

## make sure the MAC vendor and device/port fields exist
tempjson="$(jq '.macvendor+={}|.devices+=[]' <<< "${tempjson}")"

tempjson="$(jq '.ips=(.ips|to_entries|sort_by(.key|split(".")|to_entries|map((.value|tonumber)*pow(256;3-.key))|add)|from_entries)' <<< "${tempjson}")"

fancyjson="$(jq '. as $root|$root.macvendor|to_entries|map({key:.value[],value:.key})|from_entries as $vendors|($root.devices|map(.*(.ports[]|with_entries(.key|="port_"+.))))|map_values(del(.ports))|map({key:.port_mac,value:.})|from_entries as $ports|$root.ips|map_values(.port=$ports[.mac]|.vendor=$vendors[.mac[0:8]])' <<< "${tempjson}")"

jq -r '(["[?]","MAC","Vendor","Model","IP","User","Device","Port"],(to_entries|sort_by(.key|split(".")|to_entries|map((.value|tonumber)*pow(256;3-.key))|add)|.[]|[if .value.online then "[#]" else "[ ]" end,.value.mac,.value.vendor,.value.port.model,.key,.value.port.user,.value.port.desc,.value.port.port_name]))|@tsv' <<< "${fancyjson}" | column -ts $'\t'

cat <<< "${tempjson}" > arpscan.json