#!/usr/bin/env bash
# HEADER
#=======================================================================
#
#  ring -- Random INteger Generator
#
#  SYNOPSIS
#    ring n min max
#
#  DESCRIPTION
#    Shell script to generate a fixed number of random integers
#    in a given range, by default [1, 10^ceil(log10(n))].
#
#  OPTIONS
#    -h|--help          display this help and exit
#
#  EXAMPLES
#    genate n numbers (in range [1, n])
#       $ ring n
#    genate n numbers in range [a, b]
#       $ ring n a b
#
#  DEPENDENCIES
#    - GNU coreutils: head, tail, cut, grep, sed, tr
#
#  Copyringht (c) 2019 by Nicolas Mesnier <nmesnier@free.fr>
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License version 3 or
#  above as published by the Free Software Foundation.
#
#  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/>.
#
#=======================================================================
# END_OF_HEADER
#-----------------------------------------------------------------------
set -euo pipefail
#-----------------------------------------------------------------------
# *** read this header to display help
#-----------------------------------------------------------------------
SCRIPT_NAME="$(basename ${0})"
BOH=$(head -200 ${0} | grep -n "^# HEADER" | cut -f1 -d:)
EOH=$(head -200 ${0} | grep -n "^# END_OF_HEADER" | cut -f1 -d:)
function Help(){
  head -$(($EOH-1)) ${0} | tail -$(($EOH-$BOH-1)) \
    | grep -e "^#$" -e "^# " \
    | sed -e "s/^#=*//g" \
          -e "s/\${SCRIPT_NAME}/${SCRIPT_NAME}/g"
}
#-----------------------------------------------------------------------
# *** get options ***
#-----------------------------------------------------------------------
if [ ${#@} -ge 1 ] ;then
    case "${1}" in
        -h|--help)
            Help
            exit 0
            ;;
         *)
            nvalues=${1}
            ;;
    esac
    if [ ${#@} -eq 3 ];then
        min=${2}
        max=${3}
        maxvalues=$((${max}-${min}+1))
        if [ ${nvalues} -ge ${maxvalues} ];then
            msg=" *** Can't generate ${nvalues} intergers "
            msg+="in range of size ${maxvalues}!"
            echo ${msg}
            exit 1
        fi
    else
        # find n such as 10^{n-1} < nvalues < 10^n
        n=1
        while [ ${nvalues} -ne 0 ];do 
            nvalues=$(( ${nvalues} / 10 ))
            n=$(($n+1))
        done
        min=1
        max=$((10**${n}))
    fi
    items=()
    while [ ${#items[@]} -lt ${nvalues} ]
    do
        num=$(( ( RANDOM % (${max}-${min}) )  + ${min} ))
        if [[ ! "${items[@]}" =~ "${num}" ]]; then
            items[${#items[@]}]=${num}
        fi
    done
    echo ${items[@]} | tr ' ' '\n'
fi
#====================================================================eof
# vim: set tw=72 ts=2 sw=2 nu: