new-code

#!/usr/bin/env bash
# Generate a random human readable alphanumeric code

# Environment setup - Leave this block intact
# -----------------------------------------------------------------------------
set -o pipefail # set -o errexit hides errors, don't use it
[[ ${DEBUG-} ]] && set -o xtrace
SCRIPT_DIR="$(cd "${BASH_SOURCE[0]%/*}" || exit 1; pwd)"
[[ ":${PATH}:" != *:"${SCRIPT_DIR}":* ]] && export PATH="${SCRIPT_DIR}:${PATH}"
source "${SCRIPT_DIR}/bash_modules/terminal.sh"
[[ -z ${BASH_MODULES_DIR-} ]] && echo "ERROR: terminal.sh module missing" && exit 1

function ctrlc_trap() {
  log_newline
  log_warning "Script interrupted. Exiting."
  exit 130
}
trap ctrlc_trap SIGINT

function print_usage() {
  cat <<EOF
Usage: $(basename "$0") [length]

Generate a random alphanumeric code with specific constraints.
The code is designed to be readable and avoid ambiguous characters.

Optional arguments:
  length             The length of the code (default: 4)
  -h, --help         Show this help message and exit

Code constraints:
  - Alphanumeric only, no symbols
  - Does not include i, l, 1, o, 0 (ambiguous characters)
  - Always starts with a letter
  - Only uses lower-case letters: abcdefghjkmnpqrstuvwxyz
  - Only uses these numbers: 23456789
  - Probability of numbers to letters is even
EOF
}

if [[ $# -gt 1 || "${1}" == "-h" || "${1}" == "--help" ]]; then
  print_usage
  exit 1
fi

declare length="${1:-4}"

# Validate length is numeric and positive
if [[ -n "${1}" && ! "${1}" =~ ^[1-9][0-9]*$ ]]; then
  log_error "ERROR: Length must be a positive integer"
  exit 1
fi

# Define character sets
declare letters="abcdefghjkmnpqrstuvwxyz"
declare numbers="23456789"

# Extend numbers to match the length of letters for even distribution
declare extended_numbers=""
while [[ ${#extended_numbers} -lt ${#letters} ]]; do
  extended_numbers="${extended_numbers}${numbers:$((RANDOM % ${#numbers})):1}"
done

# Combine characters for selection
declare all_chars="${letters}${extended_numbers}"

# Generate the code
declare code=""
for ((i = 0; i < length; i++)); do
  if [[ $i -eq 0 ]]; then
    # Ensure the first character is a letter
    char="${letters:$((RANDOM % ${#letters})):1}"
  else
    char="${all_chars:$((RANDOM % ${#all_chars})):1}"
  fi
  code="${code}${char}"
done

# Display the result
printf "%s" "${code}"
log_newline