#!/bin/bash
# frame repeater service

# TODO
#   [X] way to send stderr to log file
#   [ ] way to set freq at start up
#   [ ] way to set Rs and M at start up
#   [ ] way to start as frame repeater or beacon

TERM_ADDR=0x2
RS=10000
DATA_BITS_PER_FRAME=256
CODE=H_${DATA_BITS_PER_FRAME}_512_4
TR_SWITCH_GPIO=21
PIRIP_PATH=/home/pi/pirip
NAME=frame_repeater
PIDFILE=/var/run/${NAME}.pid
LOGFILE=/var/log/${NAME}.log
PATH=${PIRIP_PATH}/tx:${PIRIP_PATH}/librtlsdr/build_rtlsdr/src:${PATH}
GAIN="${GAIN:-49}"

function tx_burst_rpitx {
    num_bursts=$1
    rpitx_fsk /dev/zero --code H_256_512_4 -r ${RS} -s ${RS} --testframes 3 --bursts ${num_bursts} --delay 2000 -g 21 -m 2
    #rpitx_fsk -c
}

function start_rx {
    rtl_fsk -g ${GAIN} -f 144490000 - -a 200000 -r ${RS} --code  H_256_512_4 --mask ${RS} -L $1 > /dev/null &
    echo $!>${PIDFILE}
}

function stop_service {
    echo "service stopping - bye!" 1>&2
    parent=$(cat ${PIDFILE})
    kill ${parent}
    rm ${PIDFILE}
}

case "$1" in 
    start)
        ( rtl_fsk -g 49 -f 144490000 - -a 200000 -r ${RS} --code ${CODE} --mask ${RS} --filter ${TERM_ADDR} -q -b | \
          frame_repeater ${DATA_BITS_PER_FRAME} ${TERM_ADDR} | \
          rpitx_fsk - --code ${CODE} -r ${RS} -s ${RS} -g ${TR_SWITCH_GPIO} --packed -- ) >>${LOGFILE} 2>&1 &
        echo $!>${PIDFILE}
        ;;
    start_verbose)
        # run in the foreground and log to stderr instead of a logfile
        rtl_fsk -g 49 -f 144490000 - -a 200000 -r ${RS} --code ${CODE} --mask ${RS} --filter ${TERM_ADDR} -q -b -v | \
        frame_repeater ${DATA_BITS_PER_FRAME} ${TERM_ADDR} | \
        rpitx_fsk - --code ${CODE} -r ${RS} -s ${RS} -g ${TR_SWITCH_GPIO} --packed --
        ;;
    start_loopback)
        # Send packets from Pi to RTLSDR on this machine (no filtering of packets or frame repeater)
        set -x
        verbose=1
        start_rx
        sleep 1
        if ! ps -p $(cat ${PIDFILE}); then
            echo "rtl_fsk failed to start!"
            rm ${PIDFILE}
            exit 1
        fi   
        tx_burst_rpitx $2
        stop_service
        ;;
    stop)
        stop_service
        ;;
    restart)
        $0 stop
        $0 start
        ;;
    status)
        if [ -e ${PIDFILE} ]; then
            echo ${NAME} is running, pid=`cat ${PIDFILE}`
        else
            echo$ {NAME} is NOT running
            exit 1
        fi
        ;;
    *)
        echo "Usage: sudo $0 {start|stop|status|restart}"
        echo ""
        echo "start                    - Start frame repeater service, logfile is ${LOGFILE}"
        echo "start_verbose            - Start frame repeater in foreground, no logfile"
        echo "start_loopback numBursts - Local loopback test, tx/rx numBursts"
esac

exit 0