#!/usr/bin/env bash

#
# Copyright (C) 2015 Eistec AB
#
# This file is subject to the terms and conditions of the GNU Lesser General
# Public License v2.1. See the file LICENSE in the top level directory for more
# details.
#

# Find all USB to serial devices
# iterate over usb-tty devices:
for basedev in $(find /sys/bus/usb/devices/ -regex "/sys/bus/usb/devices/[0-9]+[^:/]*" -maxdepth 2 -follow 2>/dev/null); do
    ttydirs=$(find ${basedev} -regex "${basedev}/[^/]*:.*" -mindepth 2 -maxdepth 3 -name tty -follow 2>/dev/null)
    if [ -z "${ttydirs}" ]; then
        continue
    fi
    # See if the device has any tty devices assigned to it, get the first match
    tty=$(find ${ttydirs} -maxdepth 1 -mindepth 1 -printf '%f\n' | head -n 1 2>/dev/null)
    if [ -z "${tty}" ]; then
        continue
    fi
    parent=$(echo ${basedev} | sed -e 's%\(/sys/bus/usb/devices/[^/]*\)/.*%\1%')
    serial=$(cat "${parent}/serial" 2>/dev/null)
    # split results into array

    if [ $# -lt 1 ]; then
        # No arguments given, return first found tty
        echo "/dev/${tty}"
        exit 0
    fi
    # else: Match any of the given serials
    for s in "${@}"; do
        echo "${serial}" | egrep -e "${s}" -q
        if [ $? -eq 0 ]; then
            # return first tty
            echo "/dev/${tty}"
            exit 0
        fi
    done
done
# not found
exit 1;