#!/bin/sh

set -u #abort when undefined vars are used

# Frobnicator
#
# Copyright (C) 2016 Assaf Gordon <assafgordon@gmail.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

die()
{
    BASE=$(basename "$0")
    echo "$BASE: error: $*" >&2
    exit 1
}

show_help_and_exit()
{
    BASE=$(basename "$0")
    echo \
"Frobnicator - fronbnicates files

Usage: $BASE [OPTIONS] FILE

Options:
    -h         = This help screen.
    -v         = Be verbose.
    -P POOPOO  = A random option

"
    exit
}


##
## Script start, parse command-line parameteres
##
show_help=
verbose=
poopoo=

# Parse parameters
while getopts hvp: param
do
    case $param in
    h)   show_help=1;;
    v)   verbose=1;;
    p)   poopoo="$OPTARG";;
    ?)   die "unknown/invalid command line option";;
    esac
done
shift $(($OPTIND - 1))

test -n "$show_help" && show_help_and_exit

# Ensure is one non-option parameters (the input file)
test $# -gt 1 && die "too many parameters ($*). See -h for help."
test $# -lt 1 && die "missing input file. See -h for help."

# first parameter - filename
infile="$1"
test -z "$infile" && die "missing input file. See -h for help."
test -e "$infile" \
    || die "input file '$infile' not found"

test "$poopoo" \
    && msg="poopoo = '$poopoo'" \
    || msg="no poopoo"
test "$verbose" && echo "Processing file '$infile' ($msg)"