popufare/busunit/commhub/client_utils.c

/*
 * Copyright (c) 2019 Clementine Computing LLC.
 *
 * This file is part of PopuFare.
 *
 * PopuFare 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.
 *
 * PopuFare 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with PopuFare.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <time.h>

#include <stdarg.h>

#include "../common/common_defs.h"
#include "commhub.h"
#include "client_utils.h"

gps_status      gps_stat = {0};
stop_status  stop_stat = {0};
driver_status  driver_stat = {0};
pass_status  pass_stat = {0};
bill_status  bill_stat = {0};
state_info_t state_info = {0};

//-----------------------------------------------------------------

float effective_lat() {
  if (gps_stat.gps_good) {
    return (float)gps_stat.lat;
  }
  else {
    return (float)stop_stat.lat;
  }
}

float effective_lon() {
  if (gps_stat.gps_good) {
    return (float)gps_stat.lon;
  }
  else {
    return (float)stop_stat.lon;
  }
}

//-----------------------------------------------------------------

typedef struct message_callback_struct {
  char mailbox[MAILBOX_NAME_MAX + 1];

  int ident;

  message_notify_func callback;
  void *param;

  struct message_callback_struct *next;

} message_callback;


static message_callback *dispatch_list_head = NULL;

//This function registers a callback to happen when a certain message is received.
//It takes four parameters:
//        mailbox = string containing name of mailbox to trigger this callback
//        ident   = a numeric identifier specifying both a unique identifier for this callback, and processing order
//        func  = a message handling callback function
//        param  = an untyped pointer used to pass any outside contect to the callback
//
int register_dispatch_callback(char *mailbox, int ident, message_notify_func func, void *param) {
  message_callback *p, *q, *n;

  if (!func || !mailbox) {
    return -1;
  }

  q = NULL;
  p = dispatch_list_head;

  // Scan our existing list
  //
  while (p) {
    // stop when we find a node with an identifier greater than ident or run off the end
    //
    if (p->ident > ident) {
      break;
    }

    q = p;
    p = p->next;
  }

  n = (message_callback *)malloc(sizeof(message_callback));

  if (n == NULL) {
    return -1;
  }

  // clear our new node
  //
  memset(n, 0, sizeof(message_callback));

  // copy our match string
  //
  strncpy(n->mailbox, mailbox, MAILBOX_NAME_MAX);

  // null terminate
  //
  n->mailbox[MAILBOX_NAME_MAX] = '\0';

  // record our identifier
  //
  n->ident = ident;

  // callback
  //
  n->callback = func;

  // and parameter
  //
  n->param = param;

  // register our next pointer as per above scan's determined insert point
  //
  n->next = p;

  // If we're inserting at the head of the lsit
  //
  if (q == NULL)  {
    // set the list head to n
    //
    dispatch_list_head = n;
  }
  else {
    // tweak the next pointer of the previous node to perform the insertion
    //
    q->next = n;
  }

  return 0;
}

// This function unregisters a message callback function by its mailbox name and identifier
// this allows for easy selective removal of a specific callback while still keeping the rest of the chain intact
//
int unregister_dispatch_callback(char *mailbox, int ident) {
  message_callback *p, *q;

  // if we have a bogus mailbox, give up
  //
  if (!mailbox) {
    return -1;
  }

  q = NULL;
  p = dispatch_list_head;

  // Scan our callback list looking for the identifier in question
  //
  while (p) {

    // if we find a mailbox with both a matching identifier and mailbox name, that's the one...
    //
    if ( (p->ident == ident) && !strncmp(mailbox, p->mailbox, MAILBOX_NAME_MAX) ) {
      break;
    }

    q = p;
    p = p->next;
  }

  // if we didn't find it, that is reported by the < 0 return value
  //
  if (p == NULL) {
    return -1;
  }

  // If we are removing at the head...
  //
  if (q == NULL) {
    // advance the head pointer down the list
    //
    dispatch_list_head = p->next;
  }
  else {
    // snip the node in question out mid-list
    //
    q->next = p->next;
  }

  // free the node in question
  //
  free(p);

  return 0;
}

// This function unregisters ALL callbacks in preparation for a clean exit
//
int unregister_all_callbacks() {
  message_callback *p, *q;

  q = NULL;
  p = dispatch_list_head;

  // traverse the list freeing all nodes
  //
  while (p) {
    q = p;
    p = p->next;

    free(q);
  }

  // reset our list pointers to empty state
  //
  dispatch_list_head = NULL;

  return 0;
}

//    This function is used to translate any special "Command" messages (things addressed
// by module or PID rather than mailbox, where the payload is a mailbox name for special
// notifications (primarily MAILBOX_PING and MAILBOX_EXIT).
//
static int process_addressed_message(struct message_record *msg) {
  struct message_record translated_msg;

  // If this message is special...
  //
  if ( (!strncmp((char *)msg->payload, MAILBOX_PING, MAILBOX_NAME_MAX)) ||
       (!strncmp((char *)msg->payload, MAILBOX_HUP, MAILBOX_NAME_MAX))  ||
       (!strncmp((char *)msg->payload, MAILBOX_EXIT, MAILBOX_NAME_MAX)) ) {

    // Copy the message as a whole
    //
    memcpy(&translated_msg, msg, sizeof(translated_msg));

    // Then change its mailbox name to the special mailbox specified in the payload
    //
    strncpy(translated_msg.header.mailbox_name, (char *)msg->payload, MAILBOX_NAME_MAX);
    translated_msg.header.mailbox_name[MAILBOX_NAME_MAX] = '\0';  //this is not a bug, since mailbox_name is defined as MAILBOX_NAME_MAX + 1 bytes long

    // Go and feed this through the callback chain as if it originally came on on the actual mailbox...
    //
    process_message(&translated_msg);

    return 0;
  }

  return 0;
}

//---

// Update _state_info with _gps_stat
//
int update_state_info_with_gps(state_info_t *_state_info, gps_status *_gps_stat) {
  _state_info->lat = _gps_stat->lat;
  _state_info->lon = _gps_stat->lon;
  _state_info->heading = _gps_stat->heading;
  _state_info->velocity = _gps_stat->velocity;

  _state_info->num_sats = _gps_stat->num_sats;
  _state_info->gps_good = _gps_stat->gps_good;

  _state_info->stamp = _gps_stat->stamp;
  _state_info->gpstime = _gps_stat->gpstime;

  return 0;
}

// Update _state_info with _stop_stat
//
int update_state_info_with_stop(state_info_t *_state_info, stop_status *_stop_stat) {
  _state_info->paddle = _stop_stat->paddle;
  _state_info->route = _stop_stat->route;
  _state_info->trip = _stop_stat->trip;
  _state_info->stop = _stop_stat->stop;

  _state_info->stop_lat = _stop_stat->lat;
  _state_info->stop_lon = _stop_stat->lon;

  memcpy(_state_info->stopname, _stop_stat->stopname, ( STATE_INFO_FIELD_SIZE < STOP_NAME_LEN ) ? STATE_INFO_FIELD_SIZE : STOP_NAME_LEN );
  _state_info->stopname[STATE_INFO_FIELD_SIZE-1] = '\0';

  return 0;
}

// Update _state_info with _driver_stat
//
int update_state_info_with_driver(state_info_t *_state_info, driver_status *_driver_stat) {
  _state_info->logged_in_driver = _driver_stat->logged_in_driver;
  memcpy(_state_info->driver_name, _driver_stat->driver_name, ( STATE_INFO_FIELD_SIZE < DRIVER_NAME_LEN) ? STATE_INFO_FIELD_SIZE : DRIVER_NAME_LEN );
  _state_info->driver_name[STATE_INFO_FIELD_SIZE-1] = '\0';
  _state_info->equip_num = _driver_stat->equip_num;

  return 0;
}

// Load global variable, state_info, with stat information,
// stored in local file.
// Other global variables might need to be initalized based
// on the state_info so this function was created to help
// facilitate that in the future, if needed.
//
int init_state_info(void) {
  get_state_info(&state_info);
  return 0;
}


//---

//    This function actually processes a message through the dispatch list
// using the return values of the callbacks to determine whether to stop or continue
// the return value is the return value of the last handler to have read the message.
// a return value of MESSAGE_UNHANDLED means that no handler successfully handled the message.
message_callback_return process_message(struct message_record *msg) {
  message_callback *p = dispatch_list_head;
  message_callback_return ret = MESSAGE_UNHANDLED;

  // if there is no message
  //
  if (msg == NULL)  {

    // we can't handle it
    //
    return ret;
  }

  // Walk through this list of handlers (which is maintained sorted by ident)
  //
  while (p) {

    // if the message's mailbox matches the callback's mailbox
    //
    if (!strncmp(msg->header.mailbox_name, p->mailbox, MAILBOX_NAME_MAX))  {

      // go and run the callback
      //
      ret = p->callback(msg, p->param);

      // if this callback requested a STOP, do so
      //
      if (ret == MESSAGE_HANDLED_STOP) {
        break;
      }
    }

    // otherwise, keep going...
    //
    p = p->next;

  }

  // If nobody has said STOP yet, see if this is an individually addressed message
  //
  if ( (msg->header.mailbox_name[0] == ':') || (msg->header.mailbox_name[0] == '>') ) {
    process_addressed_message(msg);
  }

  return ret;
}


//------------------------------------ SOME USEFUL DEFAULT CALLBACKS -------------------------------------------

message_callback_return ignore_message(struct message_record *msg, void *param) {
  return MESSAGE_HANDLED_STOP;
}

//------------------------------------ SYSTEM CALLBACKS -------------------------------------------------------

static message_callback_return update_gps_status(struct message_record *msg, void *param) {

  // guard against version mismatch
  //
  if (msg->header.payload_length != sizeof(gps_status))  {
    return MESSAGE_HANDLED_STOP;
  }

  memcpy(&gps_stat, msg->payload, sizeof(gps_status));    //otherwise, update our structure

  return MESSAGE_HANDLED_CONT;
}

static message_callback_return update_stop_status(struct message_record *msg, void *param) {

  // guard against version mismatch
  //
  if (msg->header.payload_length != sizeof(stop_status))  {
    return MESSAGE_HANDLED_STOP;
  }

  // otherwise, update our structure
  //
  memcpy(&stop_stat, msg->payload, sizeof(stop_status));

  return MESSAGE_HANDLED_CONT;
}

static message_callback_return update_driver_status(struct message_record *msg, void *param) {

  // guard against version mismatch
  //
  if (msg->header.payload_length != sizeof(driver_status))  {
      return MESSAGE_HANDLED_STOP;
  }

  // otherwise, update our structure
  //
  memcpy(&driver_stat, msg->payload, sizeof(driver_stat));

  return MESSAGE_HANDLED_CONT;
}

static message_callback_return update_bill_status(struct message_record *msg, void *param) {
  // guard against version mismatch
  //
  if (msg->header.payload_length != sizeof(bill_status))  {
      return MESSAGE_HANDLED_STOP;
  }

  // otherwise, update our structure
  //
  memcpy(&bill_stat, msg->payload, sizeof(bill_stat));

  return MESSAGE_HANDLED_CONT;
}

static message_callback_return update_pass_status(struct message_record *msg, void *param) {

  // guard against version mismatch
  //
  if (msg->header.payload_length != sizeof(pass_status))  {
    return MESSAGE_HANDLED_STOP;
  }

  memcpy(&pass_stat, msg->payload, sizeof(pass_stat));  //otherwise, update our structure

  return MESSAGE_HANDLED_CONT;
}

static message_callback_return polite_exit_request_message(struct message_record *msg, void *param) {
  request_polite_exit(EXIT_REQUEST_POLITE, "%s", (char *)msg->payload);
  return MESSAGE_HANDLED_CONT;
}

static message_callback_return hup_request_message(struct message_record *msg, void *param) {
  request_hup("HUP(%s)", (char *)msg->payload);
  return MESSAGE_HANDLED_CONT;
}

static message_callback_return ping_request_message(struct message_record *msg, void *param) {
  struct message_record outgoing;

  prepare_message(&outgoing, MAILBOX_PONG, msg->payload, msg->header.payload_length);
  send_message(msg->header.from_fd, &outgoing);

  return MESSAGE_HANDLED_CONT;
}

// This function unregisters the default system status callbacks
//
int unregister_system_status_callbacks() {
  unregister_dispatch_callback(MAILBOX_GPS_STATUS, CALLBACK_SYSTEM);
  unregister_dispatch_callback(MAILBOX_STOP_STATUS, CALLBACK_SYSTEM);
  unregister_dispatch_callback(MAILBOX_DRIVER_STATUS, CALLBACK_SYSTEM);
  unregister_dispatch_callback(MAILBOX_PASS_STATUS, CALLBACK_SYSTEM);
  unregister_dispatch_callback(MAILBOX_BILL_STATUS, CALLBACK_SYSTEM);

  unregister_dispatch_callback(MAILBOX_EXIT, CALLBACK_SYSTEM);
  unregister_dispatch_callback(MAILBOX_HUP, CALLBACK_SYSTEM);
  unregister_dispatch_callback(MAILBOX_PING, CALLBACK_SYSTEM);

  return 0;
}

// This function registers the default system status callbacks
int register_system_status_callbacks() {
  unregister_system_status_callbacks();

  register_dispatch_callback(MAILBOX_GPS_STATUS, CALLBACK_SYSTEM, update_gps_status, NULL);
  register_dispatch_callback(MAILBOX_STOP_STATUS, CALLBACK_SYSTEM, update_stop_status, NULL);
  register_dispatch_callback(MAILBOX_DRIVER_STATUS, CALLBACK_SYSTEM, update_driver_status, NULL);
  register_dispatch_callback(MAILBOX_PASS_STATUS, CALLBACK_SYSTEM, update_pass_status, NULL);
  register_dispatch_callback(MAILBOX_BILL_STATUS, CALLBACK_SYSTEM, update_bill_status, NULL);

  register_dispatch_callback(MAILBOX_EXIT, CALLBACK_SYSTEM, polite_exit_request_message, NULL);
  register_dispatch_callback(MAILBOX_HUP, CALLBACK_SYSTEM, hup_request_message, NULL);
  register_dispatch_callback(MAILBOX_PING, CALLBACK_SYSTEM, ping_request_message, NULL);

  return 0;
}

// This function subscribes to a handful of essential messages
//
int subscribe_to_default_messages(int fd) {
  struct message_record outgoing_msg;

  if (fd < 0) {
    return -1;
  }

  //------------- things that keep us informed about the other modules

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_GPS_STATUS, strlen(MAILBOX_GPS_STATUS));
  send_message(fd, &outgoing_msg);

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_STOP_STATUS, strlen(MAILBOX_STOP_STATUS));
  send_message(fd, &outgoing_msg);

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_DRIVER_STATUS, strlen(MAILBOX_DRIVER_STATUS));
  send_message(fd, &outgoing_msg);

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_PASS_STATUS, strlen(MAILBOX_PASS_STATUS));
  send_message(fd, &outgoing_msg);

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_BILL_STATUS, strlen(MAILBOX_BILL_STATUS));
  send_message(fd, &outgoing_msg);

  //------------- things that every process should have a crack at

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_STATUS_REQUEST, strlen(MAILBOX_STATUS_REQUEST));
  send_message(fd, &outgoing_msg);

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_EXIT, strlen(MAILBOX_EXIT));
  send_message(fd, &outgoing_msg);

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_HUP, strlen(MAILBOX_HUP));
  send_message(fd, &outgoing_msg);

  prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_PING, strlen(MAILBOX_PING));
  send_message(fd, &outgoing_msg);

  return 0;
}

//--------------------------------------------------------------------------------------------------------------

int compress_tabs_to_spaces(char *dest, char *src, int n) {
  int i;

  for (i=0; i < n; i++) {

    switch (src[i]) {
      case '\t':
      case '\r':
      case '\n':
        dest[i] = ' ';
        break;

      default:
        dest[i] = src[i];
        break;
    }

    if (src[i] == '\0') {
      break;
    }
  }

  return 0;
}

// This function is a printf-line interface to format user display messages:
//
//  target = blank IPC message to fill with this log entry
//  line = which line of the display to draw on (0 or 1)
//      priority = what message priority?
//  duration = how many seconds to display this (0 makes it the default message)
//  fmt = printf format
//  ... = printf args
//
int format_piu_message(struct message_record *target, int line, int priority, int duration, const char *fmt, ...) {
  piu_message pmsg = {0};
  va_list ap;

  pmsg.line = line;
  pmsg.priority = priority;
  pmsg.seconds = duration;

  va_start(ap, fmt);
  vsnprintf(pmsg.message, PIU_MESSAGE_LEN, fmt, ap);
  va_end(ap);

  return prepare_message(target, MAILBOX_PIU_MESSAGE, &pmsg, sizeof(pmsg));
}

// This function takes a buffer and a buffer size and puts a
// log prefix in that contains the equipment number and the local time
//
int make_log_prefix(char *prefix, int max) {
  int eqnum;
  time_t foo;
  struct tm t;

  foo = time(NULL);

  localtime_r(&foo, &t);

  // If the driver interface module has a current EQ num
  //
  if (driver_stat.equip_num > 0) {
    // use it so as not to thrash the file system
    //
    eqnum = driver_stat.equip_num;
  }
  else {
    // otherwise, get it off disk
    //
    eqnum = get_equip_num();
  }

  return snprintf(prefix, max, "EQ# %d %04d-%02d-%02d %02d:%02d:%02d ", eqnum, t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec);
}

// This function is a printf-line interface to format log messages for the server:
//
//  target = blank IPC message to fill with this log entry
//  loglevel = one of the following: LOGLEVEL_DEBUG, LOGLEVEL_WARN, LOGLEVEL_ERROR
//  fmt = printf format
//  ... = printf args
//
//  NOTE:  DO NOT UNDER ANY CIRCUMSTANCES TERMINATE A LOG MESSAGE WITH A '\n' CHARACTER!
//
int format_log_message(struct message_record *target, char loglevel, const char *fmt, ...) {
  int len = 0;
  char payload[MAX_PAYLOAD_LENGTH] = {0};
  va_list ap;

  if (!target || !fmt) {
    return -1;
  }

  switch (loglevel) {
    case LOGLEVEL_DEBUG:
    case LOGLEVEL_WARN:
    case LOGLEVEL_ERROR:
      payload[0] = loglevel;
      len += 1;
      break;

    default:
      payload[0] = LOGLEVEL_ERROR;
      len += 1;
      break;
  }

  len += make_log_prefix(payload + len, MAX_PAYLOAD_LENGTH - len);

  va_start(ap, fmt);
  len += vsnprintf(payload + len, MAX_PAYLOAD_LENGTH - len, fmt, ap);
  va_end(ap);

  return prepare_message(target, MAILBOX_BILLING_LOG, payload, len);
}

// This function printf-line interface to format messages for debug and trace purposes
//
int format_trace_message(struct message_record *target, const char *fmt, ...) {
  int len = 0;
  char payload[MAX_PAYLOAD_LENGTH] = {0};
  va_list ap;

  if (!target || !fmt) {
    return -1;
  }

  va_start(ap, fmt);
  len += vsnprintf(payload + len, MAX_PAYLOAD_LENGTH - len, fmt, ap);
  va_end(ap);

  return prepare_message(target, "DEBUG_TRACE", payload, len);
}

// This function is a printf-line interface to format messages for the driver:
//
//  target = blank IPC message to fill with this log entry
//  loglevel = one of the following: LOGLEVEL_DEBUG, LOGLEVEL_WARN, LOGLEVEL_ERROR
//  fmt = printf format
//  ... = printf args
//
//  NOTE:  DO NOT UNDER ANY CIRCUMSTANCES TERMINATE A LOG MESSAGE WITH A '\n' CHARACTER!
//
int format_driver_message(struct message_record *target, char loglevel, const char *fmt, ...) {
  int len = 0;
  char payload[MAX_PAYLOAD_LENGTH] = {0};
  va_list ap;

  if (!target || !fmt) {
    return -1;
  }

  switch(loglevel) {
    case LOGLEVEL_DEBUG:
    case LOGLEVEL_WARN:
    case LOGLEVEL_ERROR:
    case LOGLEVEL_ACCEPT:
    case LOGLEVEL_REJECT:
    case LOGLEVEL_EVENT:
      payload[0] = loglevel;
      len += 1;
      break;

    default:
      payload[0] = LOGLEVEL_ERROR;
      len += 1;
      break;
  }

  va_start(ap, fmt);
  len += vsnprintf(payload + len, MAX_PAYLOAD_LENGTH - len, fmt, ap);
  va_end(ap);

  return prepare_message(target, MAILBOX_DRIVER_NOTIFY, payload, len);
}

// This function formats a billing log entry into a form ready to pass off to the billdb process:
//
//  target = blank IPC message to fill with this log entry
//  action = string specifying billing action (ACCEPT, REJECT, PASSBACK, etc...)
//  rule =   string specifying which rule (if any) generated this billing entry
//  ruleparam = string specifying the parameter passed to the above rule
//  reason = human readable reason for the reject or accept of this rider
//  credential = string containing the magnetic or RFID credential used to identify the rider
//  logical_card_id = rider ID from pass table
//  cash_value = number of cents paid for this fare if it is a cash fare
//
//  All other required values are supplied by the system status structures maintained by the default status callbacks:
//
//  equipment number, GPS locaction, driver, paddle, route, trip, stop, and stop name
//
int format_billing_message(struct message_record *target, char *action, char *rule, char *ruleparam, char *reason, char *credential, unsigned long long logical_card_id, int cash_value) {
  int len = 0;

  char foo[MAX_PAYLOAD_LENGTH];
  char payload[MAX_PAYLOAD_LENGTH] = {0};

  if (!target)
      return -1;

  if (!action)  action = "";
  if (!rule)  rule = "";
  if (!ruleparam) ruleparam = "";
  if (!reason)  reason = "";
  if (!credential) credential = "";

  // equipment number (which bus)
  //
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", driver_stat.equip_num);
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", driver_stat.logged_in_driver);
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", stop_stat.paddle);
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", stop_stat.route);
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", stop_stat.trip);
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", stop_stat.stop);

  // the UTC timestamp of now...
  //
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", (int)time(NULL));

  // if we have a valid GPS fix, put that into the structure
  //
  if (gps_stat.gps_good)  {
    len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%f\t", gps_stat.lat);
    len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%f\t", gps_stat.lon);
  }

  // otherwise, use the location recorded in the paddle
  //
  else      {
    len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%f\t", stop_stat.lat);
    len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%f\t", stop_stat.lon);
  }

  // billing action code
  //
  compress_tabs_to_spaces(foo, action, BILLING_ACTION_LEN);
  foo[BILLING_ACTION_LEN] = '\0';
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%s\t", foo);

  // billing rule code
  //
  compress_tabs_to_spaces(foo, rule, BILLING_RULE_LEN);
  foo[BILLING_RULE_LEN] = '\0';
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%s\t", foo);

  // billing rule parameter
  //
  compress_tabs_to_spaces(foo, ruleparam, BILLING_RULEPARAM_LEN);
  foo[BILLING_RULEPARAM_LEN] = '\0';
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%s\t", foo);

  // billing reason code
  //
  compress_tabs_to_spaces(foo, reason, BILLING_REASON_LEN);
  foo[BILLING_REASON_LEN] = '\0';
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%s\t", foo);

  // billing credential code
  //
  compress_tabs_to_spaces(foo, credential, BILLING_CREDENTIAL_LEN);
  foo[BILLING_CREDENTIAL_LEN] = '\0';
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%s\t", foo);

  // rider ID from pass table
  //
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%lld\t", logical_card_id);

  // cash fare in pennies
  //
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%d\t", cash_value);

  // billing stop name
  //
  compress_tabs_to_spaces(foo, stop_stat.stopname, STOP_NAME_LEN);
  foo[STOP_NAME_LEN] = '\0';
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%s\t", foo);

  // This field is not used by the database, but distinguishes multiple identical cash fares per second
  //
  // NOTE:  This field ends without a newline OR tab, the newline is added by the billdb module before being sent
  //
  len += snprintf(payload + len, MAX_PAYLOAD_LENGTH - len, "%llu", get_usec_time());

  return prepare_message(target, MAILBOX_BILLING_LOG, payload, len);
}

/*
int main(int argc, char **argv)
{

    struct message_record msg;

    stop_stat.lat = 9999.99999f;
    stop_stat.lon = 9999.99999f;
    stop_stat.route = 99999;
    stop_stat.paddle = 99999;
    stop_stat.trip = 99;
    stop_stat.stop = 99;
    strcpy(stop_stat.stopname, "ABCDEFGIJKABCDEFGIJKABCDEFGIJKABCDEFGIJKABCDEFGIJKABCDEFGIJK123");
    driver_stat.logged_in_driver = 12345;
    driver_stat.equip_num = 12345;

    format_billing_message(&msg, "ACCEPT1ACCEPT2_", "RULE0123456789012345678", "PARA0123456789012345678", "R012345678900123456789001234567890", "C012345678900123456789001234567890", 9999);

    printf("%s", msg.payload);

    return 0;
}
*/