#!/bin/bash
# Author: Nils Gerstner

pipe="$1"
err_pipe="$2"
logfile="$3"
pid=""
err_pid=""
TAB="$(printf '\t')"

trap ">&2 echo 'Logger exiting'; ps -p $pid 2>/dev/null && kill -9 $pid; ps -p $err_pid 2> /dev/null && kill -9 $err_pid; rm -f $err_pipe $pipe 2>&1 > /dev/null" EXIT

if [[ ! -p $pipe ]] || [[ ! -p $err_pipe ]]; then
    mkfifo $pipe
    mkfifo $err_pipe
    while [[ ! -p $pipe ]] && [[ ! -p $err_pipe ]]; do
        sleep 0.01
    done
fi

log() {
    local named_pipe="$1"
    local other_pipe="$2"
    local level="$3"

    while true; do
        in_msg="$(cat $named_pipe)"
        if [ -n "$in_msg" ]; then
            if [[ "$in_msg" == 'quit' ]]; then
                >&2 echo "stopping $named_pipe"
                echo "quit" > $other_pipe
                rm -f $named_pipe
                break
            else
                #----- L O G   E X A M P L E S -----#
                #
                # Log to plain text
                # cat >> "${logfile}_plain" <<< "${level}${TAB}${in_msg}"

                # Log to json file
                jq -n -c --arg msg "${in_msg}" --arg level "${level}" '{ "level": $level,  "timestamp": (now | strftime("%Y-%m-%d %H:%M:%S")), "message": $msg }' |tee -a $logfile

                # Log to systemd journal
                # logger -t My-Logger -p ${level,,} "${msg}"
            fi
        fi
    done
}

log_info(){
    log $pipe $err_pipe INFO
}

log_err(){
    log $err_pipe $pipe  ERROR
}

while [[ ! -p $pipe ]] || [[ ! -p $err_pipe ]]; do
    sleep 0.1
done

log_info & pid="$!"
log_err & err_pid="$!"
while [[ -p $pipe ]] && [[ -p $err_pipe ]]; do
    sleep 0.01
done
ps -p $pid && kill -9 $pid
ps -p $err_pid && kill -9 $err_pid

wait
exit 0