#!/usr/bin/env bash
# ------------------------------------------------------------------------------
# Copyright (c) 2013-2022 Geoffray Levasseur <fatalerrors@geoffray-levasseur.org>
# Protected by the BSD3 license. Please read bellow for details.
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# ------------------------------------------------------------------------------

# ------------------------------------------------------------------------------
# genpwd : generate a password with different criteria
# default 16 car with up and low car, symbol and number
# The function is very slow on Windows
# ------------------------------------------------------------------------------
genpwd()
{
    local length=16
    local occurs=2 # Bug, if set to 1, seems to be ignored
    local symb=1 maj=1 min=1 numb=1
    local nbpwd=1

    for opt in $@; do
        case $opt in
        "-h" | "--help")
            echo "genpwd: generate one or more secure random password."
            echo
            echo "Usage: genpwd [options] [--extracars=<cars>] [--length=<n>] [nb_passwd]"
            echo
            echo "Options:"
            echo "	-h, --help	Display that help screen"
            echo "	-s, --nosymbols	Exclude symbols"
            echo "	-n, --nonumbers	Exclude numbers"
            echo "	-u, --noup	Exclude uppercase letters"
            echo "	-l, --nolow	Exclude lowercase letters"
            echo "	-e=<c>, --extracars=<c>"
            echo "			Add the given caracters to the possible caracter list"
            echo "	-L=<n>, --length=<n>"
            echo "			Set length of the password (default is $length)"
            echo "	-o=<n>, --occurences=<n>"
            echo "			Set the maximum occurences of a same caracter (default is $occurs)"
            echo
            echo "If the --extracars parameter is given, at least one of the given caracter will"
            echo "be used in the final password."
            echo
            echo "Please note that some caracters might be interpreted by Bash or Awk programs,"
            echo "and thus, cannot be used without provoquing errors. Those identified caracters"
            echo "are :"
            echo '	* ? \ $ { }'
            echo
            return 0
            ;;
        "-s" | "--nosymbols")
            symb=0
            ;;
        "-n" | "--nonumbers")
            numb=0
            ;;
        "-u" | "--noup")
            maj=0
            ;;
        "-l" | "--nolow")
            min=0
            ;;
        "-e"?* | "--extracars"?*)
            local extcar=$(echo "$opt" | cut -f 2- -d '=')
            ;;
        "-L"?* | "--length"?*)
            local length=$(echo "$opt" | cut -f 2- -d '=')
            if ! [[ $length =~ ^[0-9]+$ ]]; then
                disp E "The --length parameter requires a number."
                return 1
            fi
            ;;
        "-o"?* | "--occurences"?*)
            local occurs=$(echo "$opt" | cut -f 2- -d '=')
            if ! [[ $occurs =~ ^[1-9]+$ ]]; then
                disp E "The --occurs parameter requires a number from 1 to 9."
                return 1
            fi
            ;;
        "-*")
            disp E "Unknow parameter ${opt}."
            return 1
            ;;
        *)
            if ! [[ $opt =~ ^[1-9]+$ ]]; then
                disp E "Unknow parameter ${opt}."
                return 1
            else
                local nbpwd=$opt
            fi
            ;;
        esac
    done

    # Function selecting a random caracter from the list in parameter
    pickcar() {
        # When a character is picked we check if it's not appearing already twice
        # elsewhere, we choose an other char, to compensate weak bash randomizer
        while [[ -z $char ]]; do
            local char="${1:RANDOM%${#1}:1} $RANDOM"
            if [[ $(awk -F"$char" '{print NF-1}' <<<"$picked") -gt $occurs ]]; then
                unset char
            fi
        done
        picked+="$char"
        echo "$char"
    }

    disp I "Generating $nbpwd passwords, please wait..."
    for n in $(seq 1 $nbpwd); do
        {
            local carset='' # store final caracter set to use
            local picked='' # store already used caracter
            local rlength=0 # store already assigned length of caracters

            # ?, *, $ and \ impossible to use to my knowledge as it would be interpreted
            if [[ $symb == 1 ]]; then
                pickcar '!.@#&%/^-_'
                carset+='!.@#&%/^-_'
                ((rlength++))
            fi
            if [[ $numb == 1 ]]; then
                pickcar '0123456789'
                carset+='0123456789'
                ((rlength++))
            fi
            if [[ $maj == 1 ]]; then
                pickcar 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
                carset+='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
                ((rlength++))
            fi
            if [[ $min == 1 ]]; then
                pickcar 'abcdefghijklmnopqrstuvwxyz'
                carset+='abcdefghijklmnopqrstuvwxyz'
                ((rlength++))
            fi
            if [[ -n $extcar ]]; then
                pickcar "$extcar"
                carset+=$extcar
                ((rlength++))
            fi

            # Check if we have enough car to have something viable
            if [[ ${#carset} -lt $length ]]; then
                disp E 'Not enought caracters are authorised for the password length.'
                disp E 'Please allow more caracter (preferably) or reduce password lentgh.'
                return 1
            fi

            for i in $(seq 1 $(($length - $rlength))); do
                pickcar "$carset"
            done
        } | sort -R | awk '{printf "%s", $1}'
        unset picked carset rlength
        echo
    done
}
export -f genpwd

# ------------------------------------------------------------------------------
# EOF