/**
 * A collection of helper functions for common utility tasks.
 */
object HelperFunctions {
    /**
     * Computes the total number of steps needed to process the given total volume.
     *
     * @param totalVolume the total amount that needs to be processed
     * @param volumePerStep the amount to process per step
     * @return the number of steps required to process the total volume
     */
    fun calculateTotalSteps(totalVolume: Int, volumePerStep: Int) =
        totalVolume / volumePerStep + if (totalVolume % volumePerStep > 0) {
            1
        } else {
            0
        }


    /**
     * Prints a progress report to console showing current step, total steps, elapsed time, and estimated remaining time.
     *
     * @param step The current step number
     * @param of The total number of steps
     * @param dur The elapsed duration so far in milliseconds
     */
    fun report(step: Int, of: Int, dur: Long) {
        val remaining = (dur / step) * (of - step)
        print("\rStep $step of $of (${prettyTimeString(dur)} complete\t|\t~${prettyTimeString(remaining)} remaining)                               ")
    }

    /**
     * Converts a duration in milliseconds to a human-readable string.
     *
     * @param durationMillis The duration to convert, in milliseconds
     * @return A string representation of the duration, in the format XhYmZs
     */
    fun prettyTimeString(durationMillis: Long): String {
        if (durationMillis == 0L) {
            return "No time data yet"
        }
        val millisPerSecond = 1000L
        val millisPerMinute = 60L * millisPerSecond
        val millisPerHour = 60L * millisPerMinute
        return if (durationMillis > millisPerHour) {
            return "${durationMillis / millisPerHour}h${(durationMillis % millisPerHour) / millisPerMinute}m${(durationMillis % millisPerMinute) / millisPerSecond}s"
        } else if (durationMillis > millisPerMinute) {
            return "${(durationMillis % millisPerHour) / millisPerMinute}m${(durationMillis % millisPerMinute) / millisPerSecond}s"
        } else {
            "${(durationMillis % millisPerMinute) / millisPerSecond}s"
        }
    }

}