#!/bin/sh

################################################################################
#   Simple tool to test DVB tuner by snooping the signal and redirecting the
# result to the output file, which is used to compare with the input signal.
#
# - Usage:
#     tuner_test {start|stop|help}
#
################################################################################

usage() {
  cat <<EOF
usage: tuner_test {start|stop|help} [options] ...

options:
  --freq=1400000                     Intermediate tuning frequency in kHz
                                     (default = 1400 MHz)
  --rate=30000                       Symbol rate in 1000s (default = 30000)
  --rec=34                           Forward Error Correct code (default = 34)
  --system=dvbs2                     Delivery system (default = dvbs2)
  --type=ts                          Stream type to snoop on (default = ts)
  --pid=0x1FFF                       PID channel to snoop on (default = 0x1FFF)
  --outfile=/tmp/ts_file             Snoop output file (default = /tmp/ts_file)

EOF
  return 0
}

failmsg() {
  local rval=$?
  echo "FAIL: $0: $* Abort tuner test!" 1>&2
  [ ${rval} -ne 0 ] && return ${rval}
  return 1
}

parse_args() {
  local arg
  opt_action=
  opt_freq=1400000
  opt_rate=30000
  opt_fec=34
  opt_system="dvbs2"
  opt_type="ts"
  opt_pid=0x1FFF  # PID of the SFC-Transmitter.
  opt_outfile="/tmp/ts_dump"

  # First parse action.
  case "$1" in
    start) opt_action="start";;
    stop) opt_action="stop";;
    *help) usage && exit 0;;
    *) failmsg "Unknown action [$1]; try --help." || return;;
  esac
  shift

  # Then parse options.
  while [ $# -ge 1 ]; do
    # Arg starting with dash is formally an option.
    case "$1" in (-*);; (*) break;; esac
    arg=$1
    shift
    case "${arg}" in
      --) break;;
      --freq=*) opt_freq=${arg#*=};;
      --rate=*) opt_rate=${arg#*=};;
      --fec=*) opt_fec=${arg#*=};;
      --system=*) opt_system=${arg#*=};;
      --type=*) opt_type=${arg#*=};;
      --pid=*) opt_pid=${arg#*=};;
      --outfile=*) opt_outfile=${arg#*=};;
      *) failmsg "Unknown option ${arg}; try --help." || return;;
    esac
  done
}

# Starts DVB tuner, DVB snoop, and redirect results to specified output file.
start() {
  # Kill any running tuner.
  pkill -9 dvbtune

  # Start DVB tuner.
  dvbtune -s ${opt_system} -i ${opt_freq} -r ${opt_rate} -c ${opt_fec} &
  ps -ef | grep " $! " | grep -v grep >/dev/null ||
    failmsg "Failed to start tuner..." || return

  # Remove previous outfile.
  rm -rf ${opt_outfile}

  # Start DVB snoop.
  dvbsnoop -s ${opt_type} -pd 0 -ph 2 -hideproginfo ${opt_pid} >${opt_outfile} \
    2>/dev/null &
}

# Stops DVB tuner, DVB snoop, and returns output file.
stop() {
  # Stop the snoop.
  pkill -9 dvbsnoop

  # Stop the tuner.
  pkill -9 dvbtune

  # Return the output file.
  echo "Snooping output can be found in ${opt_outfile}."

  # Get md5sum of the file content.
  echo "md5sum=$(md5sum ${opt_outfile})"
}

main() {
  parse_args "$@" || return
  ${opt_action} || return
  echo "$0 ${opt_action} completed succesfully."
}

main "$@"