/* DESC: This script will scan for operators on startup and choose the one with the best signal
 * Copyright (C) 2014 NetModule AG, Switzerland
 *
 */

ME = argv[0];           /* script path */
ARGV1 = argv[1];        /* 1st script argument */
SCAN_INTERVAL = 30;     /* scan interval */
REG_TIMEOUT = 60;       /* registration timeout */

nb_syslog("starting %s", ME);

lai = nb_config_get("sim.0.lai");
if (lai != "") {
    nb_syslog("unsetting lai '%s' of SIM1", lai);
    nb_config_set("sim.0.lai=");
    sleep(5);
}

wanlink = nb_config_get("wanlink.0.name");
if (wanlink == "wwan0") {
    mode = nb_config_get("wanlink.0.mode");
    if (mode == "1") {
        nb_syslog("disabling 1st wanlink");
        nb_config_set("wanlink.0.mode=0");
        sleep(5);
    }
}


/* scan Mobile1 until we got networks */
while (1) {
    nb_syslog("scanning networks on Mobile1");
    nets = nb_scan_networks("Mobile1");
        
    nr_nets = struct_get(nets, "NETWORK_COUNT");
    if (!is_void(nr_nets) && nr_nets > 0) {
        nb_syslog("%d networks found", nr_nets);
        break;
    }

    nb_syslog("no networks found, scanning again in %ds", SCAN_INTERVAL);
    sleep(SCAN_INTERVAL);
}


networks = mkarray();
netcount = 0;

for (i = 1; i <= nr_nets; i++) {
    net = trim(struct_get(nets, sprintf("NETWORK%d_NAME", i)));
    lai = trim(struct_get(nets, sprintf("NETWORK%d_LAI", i)));
    status = struct_get(nets, sprintf("NETWORK%d_STATUS", i));

    if (is_void(net) || is_void(lai) || is_void(status)) continue;

    if (trim(tolower(status)) == "available" && net != "") {
        nb_syslog("detected network '%s' (lai %s)", net, lai);
        networks[netcount++] = mkstruct("network", net, 
                                        "lai", lai,
                                        "signal", -999); 
    } else {
        nb_syslog("skipping invalid network '%s' (%s)", net, status);
    }
}

bestnet = "";
bestlai = -1;
bestsignal = -999;

for (i = 0; i < netcount; i++) {
    network = networks[i];
    net = struct_get(network, "network");
    lai = struct_get(network, "lai");

    nb_syslog("setting network '%s' (lai %s) over Mobile1", net, lai);
    nb_config_set(sprintf("sim.0.lai=%s", lai));

    nb_syslog("waiting until we have registered to '%s'", net);
    sleep(10);

    signal = -999;
    for (r = 0; r < REG_TIMEOUT; r += 10) {
        status = nb_status("wwan");
        regstate = struct_get(status, "MOBILE1_REGISTRATION_STATE");
        nb_syslog("registration state of '%s' is '%s'", net, regstate);

        if (regstate == "registeredInHomeNetwork" || regstate == "registeredRoaming") {
            nb_syslog("waiting for signal strength of '%s' to settle down", net);
            sleep(10);
            status = nb_status("wwan");
            s = (int) struct_get(status, "MOBILE1_SIGNAL");
            if (s > -113) {
                signal = s;
                nb_syslog("%s at '%s' with %d dBm", regstate, net, signal);
                break;
            } else {
                nb_syslog("saw invalid signal strength %d", s);
            }
        }
        sleep(10);
    }

    if (bestnet == "" || bestlai == -1 || signal > bestsignal) {
        bestnet = net;
        bestsignal = signal;
        bestlai = lai;
    }
}

if (bestlai == -1) {
    nb_syslog("no best operator found");
} else {

    nb_syslog("setting best operator '%s' (lai %s)", bestnet, bestlai);
    nb_config_set(sprintf("sim.0.lai=%s", bestlai));
    sleep(5);

    nb_syslog("activating 1st wanlink");
    nb_config_set("wanlink.0.mode=1");
}

nb_syslog("done");

exit(0);