#! /bin/bash

# Width of display
width=10
# Delay (in seconds) between frames
delay=1
# Number of cursor positions to scroll in each frame
speed=2

start=0 bounce=$speed
while true; do
	# get the song
	song=$(audtool current-song)

	# Clear to beginning of line
	tput el1
	# Go to beginning of line
	tput hpa 0

	# Print $width characters starting at $start (no newline)
	printf "%s" "${song:start:width}"

	# Advance the window
	let start+=bounce

	if ((start+width >= ${#song})); then    # at or past the end
		# Go to the end of the song
		let start=${#song}-width
		# Moving backwards
		let bounce=-speed
	elif ((start <= 0)); then               # at the beginning
		# Go to the beginning
		let start=0
		# Moving forwards
		let bounce=speed
	fi

	sleep "$delay"
done