#!/bin/bash
#  $HeadURL: https://svn.pasta.freemyip.com/main/miniade/trunk/bin/nop-sh $ $LastChangedRevision: 10133 $

#  Modules
. $(miniade) || { echo "${0##*/}: ERROR: miniade failed (hint: run 'miniade' to see error)" >&2; exit 1; }

#  Configurable stuff

#  Other globals

main()
{
    local MY_ARGS PADDING EXPIRY PROGNAME MODE

    #  Defaults for options
    PADDING=3
    EXPIRY=5
    MODE=display

    #  Process options
    special_opts_handler()
    {
        case $1 in
            --padding=*) PADDING=${1#*=} ;;
            --expiry=*)  EXPIRY=${1#*=} ;;
            --reset)     MODE=reset ;;
            *)           return 1 ;;
        esac
    }
    miniade_process_options --special-opts-handler=special_opts_handler --help-handler=help MY_ARGS "$@" && set -- "${MY_ARGS[@]}"

    #  Process arguments
    [ $# = 0 ] || miniade_bad_usage

    #  Sanity checks and derivations
    miniade_get_progname PROGNAME
    CACHE_DIR=${XDG_CACHE_HOME:-$HOME/.cache}/$PROGNAME
    mkdir -p $CACHE_DIR
    CACHE_FILE=$CACHE_DIR/last-used

    #  Guts
    #  If resetting, then remove cache and exit.
    if [ $MODE = reset ]; then 
        rm -f $CACHE_FILE
        return
    fi
    #  Remove expired cache.
    if [ -f $CACHE_FILE ] && (($EPOCHSECONDS > $(stat -c %Y $CACHE_FILE) + $EXPIRY)); then
        miniade_debug 10 "main: removing expired cache ..."
        rm -f $CACHE_FILE
    fi
    #  Create cache if necessary.
    if [ ! -f $CACHE_FILE ]; then
        miniade_debug 10 "main: initialising cache ..."
        echo 0 > $CACHE_FILE
    fi
    NEXT_NUM=$(($(cat $CACHE_FILE) + 1))
    #  It's more important not to produce the same number twice than
    #  to risk there being jumps, so save the used number *before*
    #  displaying it.
    echo $NEXT_NUM > $CACHE_FILE
    printf "%0*d\\n" $PADDING $NEXT_NUM
}

help()
{
    local PROGNAME

    miniade_get_progname PROGNAME
    echo "Usage: $PROGNAME [ <standard-options> ] { --reset | [ --padding=<num> ] [ --expiry=<secs> ] }"
    echo
    echo "Defaults:"
    echo "       padding: $PADDING"
    echo "       expiry: ${EXPIRY}s"
    exit 0
}

main "$@"