/*
 * 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 <poll.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#include <time.h>

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

#define PIU_MINDER_VERSION "1.0.1"

int piu_fd = -1;
int hub_fd = -1;

device_test_vector piu_test_vector = {
  .dev_id       = "rider_ui",
  .init_string    = "/0:\r/1:\r/m:09 00 03 42 5A 44 56\r",
  .n_reply_lines   = 4,
  .reply_strings   = (char *[]){NULL, NULL, "/OK:m:09 00 03 42 5A 44 56", "/M:^"},
};

char diag[DIAG_BUFFER_SIZE] = {0};

#define PIU_NUM_LINES  2

static char *piu_set_line_cmd[PIU_NUM_LINES] = {"/0:", "/1:"};

static piu_message def_msgs[PIU_NUM_LINES] = {{0}};
static piu_message cur_msgs[PIU_NUM_LINES] = {{0}};


int update_piu_display(int line) {
  piu_message *msg;

  if( (line >= PIU_NUM_LINES) || (line < 0) ) {
    return -1;
  }

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

  msg = (cur_msgs[line].seconds == 0)?(def_msgs + line):(cur_msgs + line);

  // write the command prefix
  //
  write(piu_fd, piu_set_line_cmd[line], 3);

  // write the actual message
  //
  write(piu_fd, msg->message, strlen(msg->message));

  // write the CR to signal EOL
  //
  write(piu_fd, "\r", 1);

  //printf("%s%s\n",piu_set_line_cmd[line], msg->message);

  return 0;
}

message_callback_return handle_display_message(struct message_record *msg, void *param) {
  piu_message *cmd = (piu_message *) msg->payload;
  piu_message *tgt = NULL;

  // obtain a timestamp for NOW
  //
  time_t now = time(NULL);
  int touched = 0;


  // if we have an update for a line that doesn't exist, ignore it
  //
  if( (cmd->line >= PIU_NUM_LINES) || (cmd->line < 0) ) {
    return MESSAGE_HANDLED_CONT;
  }

  // if we're updating the default message
  //
  if(cmd->seconds == 0)  {

    // get a pointer to our message target
    //
    tgt = def_msgs + cmd->line;

    // just do it...
    //
    memcpy(tgt, cmd, sizeof(piu_message));

    // force terminate the string just in case
    //
    tgt->message[PIU_MESSAGE_LEN - 1] = '\0';


    // priority is meaningless for default messages
    //
    tgt->priority = 0;


    //if the active message on this line has expired, a change in
    // default message will need to trigger an update
    //
    if(cur_msgs[cmd->line].seconds < now) {
      touched = 1;
    }
  }
  else
  {
    // get a pointer to our message target
    //
    tgt = cur_msgs + cmd->line;


    // If the current message has expired or will expire this second (thus bringing up the default message)
    // OR the new message is of higher priority then we need to do the repacement
    //
    if( (tgt->seconds <= now) || (cmd->priority >= tgt->priority) ) {

      // perform the copy
      //
      memcpy(tgt, cmd, sizeof(piu_message));

      // force terminate the string just in case
      //
      tgt->message[PIU_MESSAGE_LEN - 1] = '\0';


      // set the expiration time on the new message to the timestamp of NOW
      // plus the desired duration
      //
      tgt->seconds = now + cmd->seconds;

      touched = 1;
    }
  }

  // if we have made any changes...
  //
  if(touched)  {
    update_piu_display(cmd->line);
  }

  return MESSAGE_HANDLED_CONT;
}

int handle_message_timeouts() {
  int i;
  time_t now = time(NULL);

  // For each display line
  //
  for(i = 0; i < PIU_NUM_LINES; i++) {

    // Check to see if it has an active current message
    //
    if(cur_msgs[i].seconds != 0) {

      // If so, see if that message has passed its expiration time
      //
      if(cur_msgs[i].seconds < now) {

        // if it has...
        //
        cur_msgs[i].seconds = 0;

        // flag it inactive
        // and update the PIU
        //
        update_piu_display(i);
      }
    }
  }

  return 0;
}

#ifdef BEEP_WITH_MAGSTRIPE_READER

char dup_notify_str[MAX_PAYLOAD_LENGTH] = {0};
long long dup_notify_usec = 0;

message_callback_return handle_DIU_beep(struct message_record *msg, void *param) {
  int is_dup;
  long long dup_usec_delta = 0;

  if(strncmp(msg->payload, dup_notify_str, MAX_PAYLOAD_LENGTH)) {
    strncpy(dup_notify_str, msg->payload, MAX_PAYLOAD_LENGTH - 1);
    dup_notify_str[MAX_PAYLOAD_LENGTH - 1] = '\0';
    is_dup = 0;
    dup_notify_usec = 0;
  }
  else {
    is_dup = 1;
    dup_usec_delta = get_usec_time() - dup_notify_usec;
    dup_notify_usec = get_usec_time();
  }

  switch(msg->payload[0])
  {
    case LOGLEVEL_EVENT:
      if(!is_dup || (dup_usec_delta >= DUP_USEC_BEEP_THRESHOLD)) {
        PIU_ACK_BEEP(piu_fd);
      }
      break;

    case LOGLEVEL_REJECT:
      if(!is_dup || (dup_usec_delta >= DUP_USEC_BEEP_THRESHOLD)) {
        PIU_ERROR_BEEP(piu_fd);
      }
      break;

    case LOGLEVEL_ACCEPT:
      if(!is_dup || (dup_usec_delta >= DUP_USEC_BEEP_THRESHOLD)) {
        PIU_ACK_BEEP(piu_fd);
      }
      break;

    case LOGLEVEL_ERROR:
      if(!is_dup || (dup_usec_delta >= DUP_USEC_BEEP_THRESHOLD)) {
        PIU_CRITICAL_BEEP(piu_fd);
      }
      break;

    default:
      break;
  }

  return MESSAGE_HANDLED_CONT;
}
#endif


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

void maintain_ipc_hub_connect(char *progname) {
  struct message_record outgoing_msg;

  // if we have no connection to the IPC hub
  if(hub_fd < 0)  {

    // try and get one
    //
    hub_fd = connect_to_message_server(progname);

    if(hub_fd >= 0)
    {

      // Subscribe to the default status messages
      //
      subscribe_to_default_messages(hub_fd);


      // Subscribe to our specific message
      //
      prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_PIU_MESSAGE, strlen(MAILBOX_PIU_MESSAGE));
      send_message(hub_fd,&outgoing_msg);

      #ifdef BEEP_WITH_MAGSTRIPE_READER

        // if BEEP_WITH_MAGSTRIPE_READER is defined, that means our diu board's speaker/amp is FUCKING BROKEN and we
        // need to intercept DIU messages and induce the magstripe reader on the PIU to beep when they occur even
        // though it is a stupid idea to do so since any other activity on the magstripe reader (like swiping a card...)
        // will cause it to either miss the card or disrupt the beeping.
        //
        prepare_message(&outgoing_msg, MAILBOX_SUBSCRIBE, MAILBOX_DRIVER_NOTIFY, strlen(MAILBOX_DRIVER_NOTIFY));
        send_message(hub_fd,&outgoing_msg);
      #endif

    }
    else
    {
      fprintf(stderr, "Cannot connect to IPC hub!\n");
    }
  }
}

int main(int argc, char **argv) {
  char line[LINE_BUFFER_SIZE] = {0};

  struct message_record incoming_msg;
  struct message_record outgoing_msg;

  struct pollfd fds[2];
  int nfd;

  int poll_return;
  int read_return;

  int i, j;

#ifdef DEBUG_PRINT
  long long int _usec_now, _usec_prv, _usec_del;
  _usec_now = get_usec_time();
  _usec_prv = _usec_now;
  _usec_del = 60000000;
#endif

  long long int _usec_ratelimit_now, _usec_ratelimit_prv, _usec_ratelimit_del;
  _usec_ratelimit_now = get_usec_time();
  _usec_ratelimit_prv = _usec_ratelimit_now;
  _usec_ratelimit_del = 1000000;

  if ( (argc>1) && (
        (strncmp(argv[1], "-h", 3)==0) ||
        (strncmp(argv[1], "-v", 3)==0) ) ) {
    printf("piu_minder version: %s\n", PIU_MINDER_VERSION);
    exit(0);
  }


  configure_signal_handlers(argv[0]);
  maintain_ipc_hub_connect(argv[0]);


  // Register our defualt system message processing callbacks
  //
  register_system_status_callbacks();


  // Register our module specific message processing callbacks
  //
  register_dispatch_callback(MAILBOX_PIU_MESSAGE, CALLBACK_USER(1), &handle_display_message, NULL);

  #ifdef BEEP_WITH_MAGSTRIPE_READER
    register_dispatch_callback(MAILBOX_DRIVER_NOTIFY, CALLBACK_USER(2), &handle_DIU_beep, NULL);
  #endif


  // loop until we get asked to exit...
  //
  while( exit_request_status == EXIT_REQUEST_NONE ) {

    RESET_WATCHDOG();

#ifdef DEBUG_PRINT
    _usec_now = get_usec_time();
    if ((_usec_now - _usec_prv) > _usec_del) {
      printf("[%lli] piu_minder: heartbeat\n", get_usec_time());
      _usec_prv = _usec_now;
    }
#endif


    maintain_ipc_hub_connect(argv[0]);

    if(piu_fd < 0) {
      piu_fd = open_rs232_device(PASSENGER_UI_PORT, USE_DEFAULT_BAUD, RS232_LINE);

      if(piu_fd >= 0) {
        read_return = test_and_init_device(piu_fd, &piu_test_vector, diag);

        if(read_return) {
          fprintf(stderr, "PIU Init Failed on %s: %s\n", PASSENGER_UI_PORT, diag);
          close(piu_fd);
          piu_fd = -1;
        }

        // If we successfully connected...
        //
        else  {

          // iterate through each line
          //
          for(j = 0; j < PIU_NUM_LINES; j++) {

            // and update the display to be current
            //
            update_piu_display(j);
          }
        }
      }
      else {

        _usec_ratelimit_now = get_usec_time();
        if ((_usec_ratelimit_now - _usec_ratelimit_prv) > _usec_ratelimit_del) {
          fprintf(stderr, "Cannot open serial port %s for PIU!\n", PASSENGER_UI_PORT);
          _usec_ratelimit_prv = _usec_ratelimit_now;
        }

      }
    }

    nfd = 0;

    if(hub_fd >= 0) {
      fds[nfd].fd = hub_fd;
      fds[nfd].events = POLLIN;
      fds[nfd].revents = 0;
      nfd++;
    }

    if(piu_fd >= 0) {
      fds[nfd].fd = piu_fd;
      fds[nfd].events = POLLIN;
      fds[nfd].revents = 0;
      nfd++;
    }

    // if we have any file descriptors, poll them
    //
    if(nfd > 0)  {
      poll_return = poll(fds, nfd, POLL_TIMEOUT);
    }

    // otherwise, whistle and look busy
    //
    else    {
      poll_return = 0;
      sleep(1);
    }


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

    // No matter what poll() returned, we need to do some basic background work here...
    //

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

    handle_message_timeouts();


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


    // if poll didn't net us any work to do,
    //
    if(poll_return < 1)  {

      //lets try again
      //
      continue;
    }

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

      //If we're looking at the PIU...
      //
      if( fds[i].fd == piu_fd )    {

        // if poll says our serial port has become bogus...
        //
        if(fds[i].revents & (POLLHUP | POLLERR | POLLNVAL))  {
          fprintf(stderr, "This is very odd... Poll returned flags %d on our serial port...\n", fds[i].revents);

          // close it
          //
          close(piu_fd);

          // flag it invalid
          piu_fd = -1;

          // and break out of the for loop to allow the while to cycle
          //
          break;
        }

        if(fds[i].revents & POLLIN) {
          read_return = read(fds[i].fd, line, sizeof(line));

          if(read_return > 0) {
            char *trav = line;

            line[read_return] = '\0';
            strip_crlf(line);

            // advance until EOL or we hit our start sentinel
            //
            while(*trav && (*trav != '/') )       {
              trav++;
            }


            // Check to see that our address header is intact...
            //
            if( (trav[0] == '/') && (trav[2] == ':') ) {
              switch(trav[1]) {
                case 'M':

                  // advance past the header
                  //
                  trav += 3;


                  // Ignore ACK message from the magstripe reader
                  //
                  if(strcmp(trav, "^")) {
                    prepare_message(&outgoing_msg, MAILBOX_TOKEN_MAG, trav, strlen(trav) + 1);
                    send_message(hub_fd, &outgoing_msg);
                  }
                  break;

                case 'R':

                  // advance past the header
                  //
                  trav += 3;

                  // Ignore null reads and
                  // spurious 1-bit reads
                  //
                  if ( (strcmp(trav,"0|0")!=0) &&
                       (strcmp(trav,"1|0")!=0) &&
                       (strcmp(trav,"1|1")!=0) ) {
                    prepare_message(&outgoing_msg, MAILBOX_TOKEN_RFID, trav, strlen(trav) + 1);
                    send_message(hub_fd, &outgoing_msg);
                  }
                  break;

                // handle warnings
                //
                case '*':

                // debugs
                //
                case '#':

                // and errors
                //
                case '!':

                  // send them all to the log server
                  //
                  format_log_message(&outgoing_msg, trav[1], "PIU Reports: %s", trav + 3);
                  send_message(hub_fd, &outgoing_msg);

                  // but in the case of errors, send them to the driver too
                  //
                  if(trav[1] == '!')  {
                    format_driver_message(&outgoing_msg, trav[1], "PIU Reports: %s", trav + 3);
                    send_message(hub_fd, &outgoing_msg);
                  }
                  break;

                // ignore any message addresses that we don't know what to do with
                //
                default:
                  printf("Ignoring command \"%s\"\n", trav);
                  break;
              }
            }
            else {
              //printf("Ignoring non-command line \"%s\"\n", trav);
            }
          }
          else
          {
            fprintf(stderr, "Read from %s returned %d!\n", PASSENGER_UI_PORT, read_return);

//close it
            close(piu_fd);
//flag it invalid
            piu_fd = -1;
//and break out of the for loop to allow the while to cycle
            break;
          }
        }

      }
//If we're looking at the IPC hub...
      else if( fds[i].fd == hub_fd )
      {
//if poll says our connection to the IPC hub has died...
        if(fds[i].revents & (POLLHUP | POLLERR | POLLNVAL))
        {
//complain
          fprintf(stderr, "The connection to the IPC hub has gone away...\n");

//close it
          close(hub_fd);
//flag it dead
          hub_fd = -1;
//break out of the for loop
          break;
        }

        // if we have mail in any of our mailboxes...
        //
        if(fds[i].revents & POLLIN)  {
          read_return = get_message(hub_fd, &incoming_msg);

          if(read_return < 0) {
            // complain
            //
            fprintf(stderr, "The connection to the IPC hub has gone away...\n");

            // close it
            //
            close(hub_fd);

            // flag it dead
            //
            hub_fd = -1;

            // break out of the for loop
            //
            break;
          }
          else {
            message_callback_return msg_status;
            msg_status = process_message(&incoming_msg);
            if (msg_status < 0) { }
          }

        }

      }
    }
  }

  printf("Exiting.\n");
  close(piu_fd);
  close(hub_fd);

  return 0;
}