#!/bin/bash
#
# 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/>.
#

# This script expects to be called as root from a cron job.
#
# This script will do some basic monitoring of different pieces
# of the system.
# If a problem is discovered, this program will attemp to report
# and, potentially, try to fix them.
#

VERBOSE=2

bindir=/home/bus/bin
cfgdir=/home/bus/config
i2cdev=/dev/i2c-1
piddir=/tmp
ptydir=/tmp
logdir=/tmp

popmonlog=/tmp/popmon.log

if [[ "$VERBOSE" -gt 0 ]] ; then
  ts=`date -u +'%s.%N'`
  echo "# $ts [$$] popufare_monitor running" >> $popmonlog
fi

function setup_PIU_socat() {
  if [[ -e $piddir/socat.pid ]] ; then
    _p=`cat $piddir/socat.pid`
    if [[ -e /proc/${_p} ]] ; then kill -9 $_p ; fi
    rm -f $piddir/socat.pid
  fi

  rm -f /dev/ttyPIU
  rm -f $ptydir/ttyPIUich

  if [[ "$VERBOSE" -gt 0 ]] ; then
    ts=`date -u +'%s.%N'`
    echo "# $ts [$$] popufare_monitor: starting socat" >> $popmonlog
  fi

  socat -d -d pty,raw,echo=0,link=$ptydir/ttyPIUich pty,raw,echo=0,link=/dev/ttyPIU > $logdir/socat.log 2>&1 &
  echo "$!" > $piddir/socat.pid
}

function setup_I2C_PIU_bridge() {
  if [[ -e $piddir/ichthyic.pid ]] ; then
    _p=`cat $piddir/ichthyic.pid`
    if [[ -e /proc/${_p} ]] ; then kill -9 $_p ; fi
    rm -f $piddir/ichthyic.pid
  fi

  if [[ "$VERBOSE" -gt 0 ]] ; then
    ts=`date -u +'%s.%N'`
    echo "# $ts [$$] popufare_monitor: starting ichthyic i2c to PIU bridge" >> $popmonlog
  fi

  $bindir/ichthyic-passthrough --i2c $i2cdev --pty $ptydir/ttyPIUich -v -v -L $logdir/ichthyic.log >> $popmonlog 2>&1 &
  echo "$!" > $piddir/ichthyic.pid
}

# If we have an appropriate drop file and I2C is enabled, 
# make sure socat is running and our shim program is running.
#
if [[ -e $cfgdir/popufare.ichthyic &&  -e $i2cdev ]] ; then

  ## make sure socat is running to tie ttyPIU to ttyPIUich
  ## together
  ##
  if [[ ! -e $piddir/socat.pid ]] ; then
    setup_PIU_socat
  fi

  p=`cat $piddir/socat.pid`
  if [[ ! -e /proc/${p} ]] ; then

    if [[ "$VERBOSE" -gt 1 ]] ; then
      ts=`date -u +'%s.%N'`
      echo "## $ts [$$] stale socat.pid file? no process id found for $p" >> $popmonlog
    fi

    setup_PIU_socat
  fi

  ## Now run the shim program to connect the I2C to the ttyPIUich line
  ##
  if [[ ! -e $piddir/ichthyic.pid ]] ; then
    setup_I2C_PIU_bridge
  fi

  p=`cat $piddir/ichthyic.pid`
  if [[ ! -e /proc/${p} ]] ; then

    if [[ "$VERBOSE" -gt 1 ]] ; then
      ts=`date -u +'%s.%N'`
      echo "## $ts [$$] stale ichthyic.pid file? no process id found for $p" >> $popmonlog
    fi

    setup_I2C_PIU_bridge
  fi

fi

if [[ "$VERBOSE" -gt 0 ]] ; then
  ts=`date -u +'%s.%N'`
  echo "# $ts [$$] popufare_monitor finished" >> $popmonlog
fi

exit 0