#!/bin/bash --posix

set -e

DIRECTORY=""
HOUR=12
DAYS_OLD=3

usage() {
  printf "%s\n" "Usage: Autodelete-Files  -d <path>
  --directory <dir> | -d <dir>
    Example:
      --directory ~/trash/
  --hour <int < 24> | -h <int < 24>
    Example:
      --hour 5
    Default: 12
  --days-old <int > 0> | -o <int > 0>
    Example:
      --days-old 3
    Default: 3"

}

error() {
  printf "\n%s\n" "$1" >&2
  exit 1
}

confirmation() {
  while true; do
  read -p "${1}" -n 1 -r choice
  case "$choice" in
    y|Y ) return 1;;
    n|N ) return 0;;
    * ) echo -e "\nInput must be either y, Y, n, or N";;
  esac
done
}

while :; do
  case $1 in
    -h | -\? | --help)
      usage # Display a usage synopsis.
      exit
      ;;
    --) # End of all options.
      shift
      break
      ;;
    -d | --directory)
      shift
      DIRECTORY="${1}"
      ;;
    -h | --hour)
      shift
      HOUR="${1}"
      ;;
    -o | --days-old)
      shift
      DAYS_OLD="${1}"
      ;;
    -?*)
      printf 'Unknown option: %s\n' "$1" >&2
      usage
      error
      ;;
    *) # Default case: No more options, so break out of the loop.
      break ;;
  esac

  shift
done


[[ "${DIRECTORY}" == "" ]] && error "A directory must be provided!"
[[ -d "${DIRECTORY}" ]] && error "The given directory ${DIRECTORY} was invalid"

[[ "${HOUR}" -gt 23 ]] && error "Hour may be no more than 23"
[[ "${HOUR}" -lt 0 ]] && error "Hour may be no less than 0"
[[ ! "${HOUR}" -eq "${HOUR}" ]] && error "Hour must be a number"

[[ ! "${DAYS_OLD}" -eq "${DAYS_OLD}" ]] && error "Days-old must be a number"

NEW_CRON_ENTRY="00 ${HOUR} * * * find ${DIRECTORY} -mtime +${DAYS_OLD} -exec rm {} \;"

crontab -l | { cat; echo "${NEW_CRON_ENTRY}"; } | crontab -