/* DESC: This script will execute commands received by SMS.
     * Copyright (C) 2012 NetModule AG, Switzerland
     */
     
    INTERVAL        = 10;                           /* only run every 10 seconds                    */
    MAXMSG          = 5;                            /* process max. 5 msgs                          */
    MAXAGE          = 300;                          /* message mustn't be older than 5 mins         */
    MAXLINES	    = 32;			    /* max. number of lines in msg (incl. header)   */
    AUTH            = 1;                            /* perform authentication                       */
    ADMPWD          = "";                           /* password used for authentication             */
    IGNORECASE      = 1;                            /* ignore upper-/lower-case                     */
    SENDERS         = mkarray(/* "+123456789" */);  /* allowed senders                              */
     
    /* check if we should perform authentication */
    if (argc == 2 && argv[1] == "noauth") {
        AUTH = 0;
    }
     
    /* retrieve password */
    if (AUTH) {
        if (strlen(ADMPWD) == 0) {
            /* use configured admin password */
            ADMPWD = nb_config_get("admin.password");
            if (strlen(ADMPWD) > 0) {
                nb_syslog("using admin password for authentication");
            } else {
                /* not there -> use a default password instead */
                nb_syslog("using default password for authentication");
                ADMPWD = "admin01";
            }
        }
        if (IGNORECASE) ADMPWD = tolower(ADMPWD);
    }
     
    /* parse message */
    string parse (string msg)
    {
        /* read by line */
        lnr = 0;
        ishdr = 1;
        tlnr = 0;
        allowed = (length(SENDERS) == 0) ? 1 : 0;
     
        lp = msg;
        for (lnr = 0; lnr < MAXLINES && strlen(lp) > 0; lnr++) {
            pos = strchr(lp, "\n");
        	if (is_void(pos)) pos = strlen(lp);
     
            line = left(lp, pos);
    	lp = substr(lp, pos + 1);
     
            if (strlen(line) == 0) {
                /* saw header separator */
                ishdr = 0;
                continue;
            }
            if (ishdr) {
                /* saw header line */
                if (left(line, 5) == "Sent:") {
                    /* check age of message */
                    sentdate = trim(substr(line, 5));
                    sent = strptime(sentdate, "%Y-%m-%d %H:%M:%S");
     
                    if (!is_void(sent)) {
                        /* got a valid sent date */
                        now = localtime(time());
                        age = mktime(now) - mktime(sent);
                        nb_syslog("message has been sent %ds ago", age);
                        if (age > MAXAGE) {
                        	nb_syslog("rejecting too old message");
                            return "";
                        }
                    } else {
                        nb_syslog("time check has been omitted");
                    }
                } else if (left(line, 5) == "From:") {
                    from = substr(line, 6);
                    if (length(SENDERS) > 0) {
                        for (s = 0; s < length(SENDERS); s++) {
                            sender = SENDERS[s]; 
                            if (left(from, strlen(sender)) == sender) {
                                allowed = 1;
                                break;
                            }
                        }
                    }
                    if (allowed == 0) {
                        nb_syslog("rejecting message from unknown sender %s", from);
                        return "";
                    } else {
                        nb_syslog("sender %s can pass", from);
                    }
                }
            } else {
                /* saw text line */
                if (IGNORECASE) line = tolower(line);
     
                if (AUTH && tlnr == 0) {
                    /* first line of message must contain the password */
                    if (left(line, strlen(ADMPWD)) != ADMPWD) {
                        nb_syslog("authentication failed");
                        return "";
                    } else {
                        nb_syslog("authentication succeeded");
                    }
                } else if ((AUTH && tlnr == 1) || (!AUTH && tlnr == 0)) {
                    /* this line must contain the command */
                    if (left(line, 6) == "reboot") {
                        return "reboot";
                    } else if (left(line, 7) == "connect") {
                        return "connect";
                    } else if (left(line, 10) == "disconnect") {
                        return "disconnect";
                    } else if (left(line, 6) == "status") {
                        return "status";
                    } else if (left(line, 6) == "output") {
                        return left(line, 13);
                    } else if (left(line, 5) == "sleep") {
                        return left(line, 13);
                    }
                } else {
                    break;
                }
                tlnr++;
            }
        }
     
        nb_syslog("no command detected");
     
        return "";
    }
     
    int setdio (string cmd) 
    {
        newstate = substr(cmd, 9, 3);
        port = substr(cmd, 7, 1);
     
        if (port != "1" && port != "2") {
            nb_syslog("invalid DIO port %s\n", port);        
            return -1;
        }     
        if (newstate == "on") { 
            st = 1;
        } else if (newstate == "off") { 
            st = 0;
        } else  {         
            nb_syslog("invalid new DIO state %s\n", newstate);
            return -1;
        }        
     
        rc = nb_dio_set(sprintf("out%s", port), st);
        if (rc) {
            nb_syslog("Unable to set state %s for DIO output port %s\n", newstate, port);
            return -1;
        } else {            
            nb_syslog("Setting state %s for DIO output port %s\n", newstate, port);
            return 0; 
        }
    }


    int setsleep (int minutes)
	{
	nb_syslog("Sleep for %i minutes",minutes);
		// we will set the wakeup time in 9- 
	nb_wakeup(minutes*60);
	nb_syslog("Triggering deep sleep mode by sms");

	res = nb_poweroff();
	if (res != 0) {
		nb_syslog("failed unexpectedly");
	}	


	}    

    /* check if we got stressed */
    LASTFILE = "/tmp/sms-control.last";
    last = 0;
     
    fp = fopen(LASTFILE, "r");
    if (fp) {
        /* we have been run at least one time */
        str = fread(fp, 32);
        if (str) last = (int) str;
        fclose(fp);
    }
     
    now = mktime(localtime(time()));
    elapsed = now - last;
    if (elapsed > 0 && elapsed < INTERVAL) {
        nb_syslog("we have ben run %d seconds ago. skipping.", elapsed);
        exit(0);
    }
     
    /* record timestamp */
    fp = fopen(LASTFILE, "w+");
    if (fp) {
        str = sprintf("%d", now);
        fwrite(fp, str);
        fclose(fp);
    }
     
    /* read inbox */
    msgs = nb_sms_list();
    nr_msgs = length(msgs);
     
    if (nr_msgs == 0) {
        nb_syslog("there are no messages in your inbox");
        exit(0);
    }
     
    nb_syslog("you have %d message(s) in your inbox", nr_msgs);
     
    /* track states */
    reboot = 0;
    connecting = 0;
    disconnecting = 0;
     
     
    /* only process latest messages */
    start = nr_msgs - MAXMSG;
    if (start < 0) start = 0;
     
    for (i=start; i<nr_msgs; i++) {
        msg = nb_sms_retrieve(msgs[i]);
        if (!msg) continue;
     
        nb_syslog("processing message %d of %d (ID %s)", 
                   i, nr_msgs, msgs[i]);
     
        cmd = parse(msg);
        if (cmd == "reboot") {   
            nb_syslog("reboot command received");
            reboot = 1;
        } else if (cmd == "connect") {
            nb_syslog("connect command received");
            if (connecting) {
                nb_syslog("already connecting");
            } else {
                /* enable first wanlink */
                nb_config_set("wanlink.0.mode=1");
                connecting = 1;
            }
        } else if (cmd == "disconnect") {
            nb_syslog("disconnect command received");
            if (disconnecting) {
                nb_syslog("already disconnecting");
            } else {
                /* disable first wanlink */
                nb_config_set("wanlink.0.mode=0");
                disconnecting = 1;
            }
        } else if (cmd == "status") {
            nb_syslog("status command received");
            rcpt = nb_sms_header(msgs[i], "From");
            if (rcpt) {
                id = nb_sms_send(rcpt, nb_status_summary());
                if (!id) {
                    nb_syslog("unable to send status message to %s", rcpt);
                } else {
                    nb_syslog("successfully queued status message to %s (ID %s)", rcpt, id);
                }
            }
        } else if (left(cmd,6) == "output") {
            nb_syslog("dio out command received");
            setdio(cmd);
        } else if (left(cmd,5) == "sleep") {
            nb_syslog("dio out command received");
            setsleep(right(cmd,strlen(cmd)-5));
        } else {
            nb_syslog("ignoring invalid message");
        }
     
        /* delete message  */
        ret = nb_sms_delete(msgs[i]);
        if (ret == 0) nb_syslog("deleted message %s", msgs[i]);
    }
     
    if (reboot == 1) {
        /* trigger reboot  */
        nb_syslog("rebooting system");
        nb_reboot();
    }
     
    exit(0);