shuffle-playlist.sh.in

#!/usr/bin/env bash

usage() {
	local old_xtrace
	old_xtrace="$(shopt -po xtrace || :)"
	set +o xtrace

	{
		echo "${script_name} - Randomly shuffle an M3U playlist."
		echo "Usage: ${script_name} [flags] <M3U playlist>"
		echo "Option flags:"
		echo "  -o --output-file - Shuffle list output file. Default: '${out_file}'."
		echo "  -h --help        - Show this help and exit."
		echo "  -v --verbose     - Verbose execution. Default: '${verbose}'."
		echo "  -g --debug       - Extra verbose execution. Default: '${debug}'."
		echo 'Input:'
		echo "  '${playlist_file}'"
		echo "Info:"
		print_project_info
	} >&2
	eval "${old_xtrace}"
}

process_opts() {
	local short_opts="o:hvg"
	local long_opts="output-file:,help,verbose,debug"

	local opts
	opts=$(getopt --options ${short_opts} --long ${long_opts} -n "${script_name}" -- "$@")

	eval set -- "${opts}"

	while true ; do
		# echo "${FUNCNAME[0]}: (${#}) '${*}'"
		case "${1}" in
		-o | --output-file)
			out_file="${2}"
			shift 2
			;;
		-h | --help)
			usage=1
			shift
			;;
		-v | --verbose)
			verbose=1
			shift
			;;
		-g | --debug)
			verbose=1
			debug=1
			keep_tmp_dir=1
			set -x
			shift
			;;
		--)
			shift
			playlist_file="${1:-}"
			if [[ ${playlist_file} ]]; then
				shift
			fi
			extra_args="${*}"
			break
			;;
		*)
			echo "${script_name}: ERROR: Internal opts: '${*}'" >&2
			exit 1
			;;
		esac
	done
}

#===============================================================================
export PS4='\[\e[0;33m\]+ ${BASH_SOURCE##*/}:${LINENO}:(${FUNCNAME[0]:-main}):\[\e[0m\] '

SECONDS=0
start_time="$(date +%Y.%m.%d-%H.%M.%S)"

real_source="$(realpath "${BASH_SOURCE}")"
SCRIPT_TOP="$(realpath "${SCRIPT_TOP:-${real_source%/*}}")"
script_name="${real_source##*/}"

trap "on_exit 'Failed'" EXIT
trap 'on_err ${FUNCNAME[0]:-main} ${LINENO} ${?}' ERR
trap 'on_err SIGUSR1 ? 3' SIGUSR1

set -eE
set -o pipefail
set -o nounset

source "${SCRIPT_TOP}/audx-lib.sh"

out_file="/tmp/audx-shufflelist-${start_time}.m3u"
usage=''
verbose=''
debug=''
playlist_file=''

process_opts "${@}"

if [[ ${usage} ]]; then
	usage
	trap - EXIT
	exit 0
fi

print_project_banner

if [[ ${extra_args} ]]; then
	set +o xtrace
	echo "${script_name}: ERROR: Got extra args: '${extra_args}'" >&2
	usage
	exit 1
fi

shuf="${shuf:-shuf}"
check_program "shuf" "${shuf}"

if [[ ! ${playlist_file} ]]; then
	set +o xtrace
	echo "${script_name}: ERROR: No input file." >&2
	usage
	exit 1
fi

if [[ ! -f ${playlist_file} ]]; then
	set +o xtrace
	echo "${script_name}: ERROR: Bad input file '${playlist_file}'" >&2
	usage
	exit 1
fi

playlist_file="$(realpath -e "${playlist_file}")"

if [[ ${verbose} ]]; then
	echo "${script_name}: INFO: playlist = '${playlist_file}'"
fi

readarray -t lines_array < "${playlist_file}"

line_count="${#lines_array[@]}"

declare -a header_array=()
declare -a data_array=()

in_header=1

for (( id = 1; id <= ${line_count}; id++ )); do
	line="${lines_array[$(( id - 1 ))]}"

	if [[ "${line::1}" = '#' ]]; then
		if [[ ${in_header} ]]; then
			if [[ ${verbose} ]]; then
				echo "${id}: (header) = '${line}'" >&2
			fi
			header_array=("${header_array[@]}" "${line}")
			continue
		fi
		if [[ ${verbose} ]]; then
			echo "${id}: (comment) = '${line}'" >&2
		fi
		continue
	fi

	in_header=''

	if [[ ! "${line}" ]]; then
		if [[ ${verbose} ]]; then
			echo "${id}: (blank) = '${line}'" >&2
		fi
		continue
	fi

	if [[ ${verbose} ]]; then
		echo "${id}: (data) = '${line}'" >&2
	fi
	data_array=("${data_array[@]}" "${line}")
done


if (( ${#header_array[@]} == 0 )); then
	set +o xtrace
	echo "${script_name}: ERROR: No M3U header found in '${playlist_file}'" >&2
	exit 1
fi

if (( ${#data_array[@]} == 0 )); then
	set +o xtrace
	echo "${script_name}: ERROR: No data found in '${playlist_file}'" >&2
	exit 1
fi

header_count="${#header_array[@]}"
data_count="${#data_array[@]}"

if [[ ${verbose} ]]; then
	{
		echo "data_count = '${data_count}'"
		echo
	} >&2
fi

echo -n '' > "${out_file}"

for (( id = 1; id <= ${header_count}; id++ )); do
	header="${header_array[$(( id - 1 ))]}"
	echo "${header}" >> "${out_file}"
done

echo "#COMMENT:AUDX shuffle-playlist - ${start_time}" >> "${out_file}"
echo >> "${out_file}"

declare -a random_array

fill_random_array "${data_count}" data_array random_array

for (( i = 0; i < ${data_count}; i++ )); do
	echo "${random_array[i]}" >> "${out_file}"
done

if [[ ${verbose} ]]; then
	{
		echo '-------------------------'
		cat "${out_file}"
		echo '-------------------------'
	} >&2
fi

echo "INFO: Wrote ${data_count} lines." >&2
echo "INFO: Playlist in '${out_file}'." >&2

trap "on_exit 'Success'" EXIT
exit 0