#!/usr/bin/env sh
# -*- sh -*-

: "${RADIO_STATIONS:=${XDG_CONFIG_HOME:-$HOME/.config}/radio/stations}"
: "${RADIO_PLAYER:=$(command -v mpv 2>/dev/null)}"

_radio_url=1
_radio_desc=2
_radio_tags=3

RADIO_PID_FILE=/tmp/radio.pid
RADIO_STATUS_FILE=/tmp/radio.status

usage() {
	cat <<EOF
RADIO: play the radio
USAGE:	radio -h
	radio -k
	radio [-s|-S]
	radio -l [QUERY]
	radio [STATION]

PARAMETERS:
 STATION	Radio station to play.  Stations are defined in
		\$RADIO_STATIONS (default: $RADIO_STATIONS).
		If STATION matches more than one station, or if it
		isn't present, radio will display a menu to select
		from.

FLAGS:
 -h		Show this help.
 -k		Kill the currently-playing radio invocation.
 -K		Kill all instances of $RADIO_PLAYER.
 -r		Begin playing most recently-played radio, or prompt user.
 -e		Edit \$RADIO_STATIONS using \$EDITOR.
 -s		Show radio's status and exit.
 -S		Show radio's status until the user quits with C-c.
 -l [QUERY]	List all known stations and exit.
		If QUERY is present, filter the list to those stations
		matching QUERY.

See radio(1) and radio.stations(5) for more details. (TODO)
EOF
	exit ${1:-0}
}

main() {
	while getopts :kKrsShel: opt; do
		case $opt in
		h) usage ;;
		k) _radio_kill ;;
		K)
			pkill "$RADIO_PLAYER"
			exit
			;;
		r) set -- "$(cat /tmp/radio.last_played)" ;;
		e) _radio_edit ;;
		s) _radio_status ;;
		S) _radio_status -f ;;
		l) _radio_list "$OPTARG" ;;
		:)
			case "$OPTARG" in
			l) _radio_list ;;
			*)
				echo >&2 "Option -$OPTARG requires an argument"
				exit 1
				;;
			esac
			;;
		\?)
			echo >&2 "Uknown option: -$OPTARG"
			exit 1
			;;
		esac
	done
	shift $((OPTIND - 1))
	_radio_play "$@"
}

_radio_status() {
	trap 'echo;exit 0' INT
	if [ "x$1" = x-f ]; then
		follow=-f
	else
		follow=
	fi
	tail $follow "$RADIO_STATUS_FILE"
	echo
	exit
}

_radio_play() {
	candidates="$(sed -e 1d -e '/^#/d' "$RADIO_STATIONS" | grep -i "$1")"
	if [ -z "$candidates" ]; then
		candidates="$(sed -e 1d -e '/^#/d' "$RADIO_STATIONS")"
	fi
	if [ "$(printf '%s\n' "$candidates" | wc -l)" -gt 1 ]; then
		printf '%s\n' "$candidates" | cut -f $_radio_desc | cat -n -
		read -p "Radio> " radio
		if ! (echo "$radio" | grep -qE '^[0-9]+$'); then
			exit 1
		fi
		station="$(printf '%s\n' "$candidates" | head -n "$radio" | tail -n 1)"
	else
		station="$candidates"
	fi

	echo "$station" | cut -f $_radio_desc >/tmp/radio.last_played

	if [ -f "$RADIO_PID_FILE" ]; then
		_radio_kill_impl
	fi

	echo >&2 "Playing $(echo "$station" | cut -f $_radio_desc)..."
	"$RADIO_PLAYER" "$(echo "$station" | cut -f $_radio_url)" >"$RADIO_STATUS_FILE" 2>&1 &
	echo $! >"$RADIO_PID_FILE"
	exit
}

_radio_kill_impl() {
	while xargs -a "$RADIO_PID_FILE" kill 2>/dev/null; do
		printf '.'
	done
}

_radio_kill() {
	if ! [ -f "$RADIO_PID_FILE" ]; then
		echo >&2 "I don't think radio is running."
		exit 1
	fi
	printf >&2 '%s' "Killing radio"
	_radio_kill_impl
	rm "$RADIO_PID_FILE"
	echo
	exit
}

_radio_edit() {
	exec $EDITOR "$RADIO_STATIONS"
}

_radio_list() {
	sed 1d "$RADIO_STATIONS" |
		grep "$1" |
		awk '
	BEGIN { FS="\t"; }
	$0 !~ /^#/ {
	   descstr = $'$_radio_desc';
	   urlstr = $'$_radio_url';
	   tagstr = $'$_radio_tags';
	   printf "%-23s\t", substr(descstr,1,20) (length(descstr)>20?"...":"");
	   printf "%-23s\t", substr(tagstr,1,20) (length(tagstr)>20?"...":"");
	   printf "%-23s\n", substr(urlstr,1,20) (length(urlstr)>20?"...":"");
	}'
	exit
}

main "$@"