#!/bin/bash

countdown() {
        STARTTIME=$(date +%s%N)
        MAXTIME=$1
        ACCURACY=${2:-0.10}
        NUMLEN=${#1}
        BANLEN=$(( ${COLUMNS:-$(tput cols)} - $NUMLEN - 9 ))
        SPINNER=("/" "-" "\\" "|")
        N=0

        [ $MAXTIME != "${MAXTIME//[^0-9]}" -o -n "$MAXTIME" ] || echo "Usage: $(basename $0) <seconds> [accuracy]"
        ENDTIME=$(( $STARTTIME + ${MAXTIME}000000000 ))
        NEWTIME=$(date +%s%N)
        while [ "$NEWTIME" -lt "$ENDTIME" ] ; do
                PCT=$(( 100 * $SECONDS / $MAXTIME ))
                FULL=$(( $BANLEN * $SECONDS / $MAXTIME ))
                EMPTY=$(( $BANLEN - $FULL ))
                let N++

                tput cr; tput el
                printf "%${NUMLEN}d [" "$(( $MAXTIME - $SECONDS ))"
                for (( X=0 ; X < FULL  ; ++X )); do echo -n "${SPINNER[$(( $N % ${#SPINNER[@]} ))]}"; done
                #echo -n "${SPINNER[$(( $N % ${#SPINNER[@]} ))]}"
                for (( X=0 ; X < EMPTY ; ++X )); do echo -ne '-'; done
                printf "] %3d%%" "$PCT"

                sleep $ACCURACY
                NEWTIME=$(date +%s%N)
        done
        echo
}