commit 02aece5e6e89e18b2a6cdaa17fbef590fd6ab4b9
Author: Kimapr <kimapr@mail.ru>
Date:   Tue Dec 17 23:25:02 2024 +0500

    break inexistence of this

diff --git a/play6 b/play6
new file mode 100755
index 0000000..6895b28
--- /dev/null
+++ b/play6
@@ -0,0 +1,337 @@
+#!/bin/sh
+#
+# The Playlist Jonkler
+#
+# usage: play6 <command> <playlist file>
+# commands: tell: list files in playlist
+#           tell_w: list playlist entry weights
+#           tell_l: list playlist entry lengths
+#           gen: output shuffled playlist
+#           play: play music with mpv
+#
+# playlist file is shell commands.
+# you shall run the `collect` command inside the playlist file.
+#
+#     collect <weight> <file> [...]
+#
+# for example:
+#
+#     collect \
+#         100 epic_music.mp3 \
+#         50 less_epic_music.webm
+#
+# if the playlist file does anything else, including, but not limited to:
+#
+# - executing commands that are not `collect`
+# - setting any variable
+# - referencing any variable
+#
+# the behavior is undefined.
+#
+# the program will assign a probability to each entry.
+# the probability is proportional to the entry's weight and
+# inversely proportional to the file's duration.
+#
+# the program will generate a shuffled playlist like this:
+#
+#   1. pick a random entry
+#   2. if it's 1th last entry output, return to #1 with 100% probability
+#      (unless there is only one entry in the playlist)
+#   3. if it's 2th last entry output, return to #1 with 91% probability
+#   4. if it's 3th last entry output, return to #1 with 70% probability
+#   5. output filename of chosen entry
+#
+# dependency : mpv (only for `play music with mpv`)
+#              ffprobe
+#              POSIX.1-2017 compatible system
+#              /dev/urandom or /dev/random
+#
+# this program is godawful and if it explodes
+# its your fault for being foolish enough to use it
+#
+cd "$(dirname "$(command -v "$0")")" || exit
+mktfifo() {
+	{ mkfifo "$(printf "$(test -z "$TMPDIR" && printf '/tmp' ||
+	printf "%s" "$TMPDIR")/pipe.$(rand).$(rand)$1" | tee /dev/fd/3)"; } 3>&1
+}
+if (printf '' | base64) >/dev/null 2>&1; then
+	_list_enc() {
+		printf :
+		base64 -w0
+		printf '\n'
+	}
+	_list_dec() {
+		printf '%s' "${1#:}" | base64 -d
+	}
+else
+	_list_enc() {
+		printf :
+		od -An -b | sed -e 's/[0-9][0-9]*/\\0\0/g;s/\s//g' | tr -d '\n'
+		printf '\n'
+	}
+	_list_dec() {
+		printf '%b' "$(printf '%s' "${1#:}" | base64 -d)"
+	}
+fi
+list_mk() {
+	for _list_mk_arg; do
+		printf '%s' "$_list_mk_arg" | _list_enc
+	done
+}
+list_slice() {
+	[ $# = 2 ] || return 1
+	if [ $1 -gt $2 ]; then
+		list_slice $2 $1;
+		return
+	fi
+	_list_slice_i=1
+	while read -r line; do
+		if test $_list_slice_i -gt $2; then
+			break
+		fi
+		if test $_list_slice_i -ge $1; then
+			printf '%s\n' "$line"
+		fi
+		_list_slice_i=$((_list_slice_i+1))
+	done
+	unset _list_slice_i
+}
+list_len() {
+	tr -cd : | wc -c
+}
+list_get() {
+	list_slice $1 $1 | list_xargs printf '%s'
+}
+inarg() {
+	_inarg_arg="$1"
+	shift 1
+	printf '%s\n' "$(printf '%s' "$_inarg_arg")" | "$@"
+	unset _inarg_arg
+}
+list_xargs() {
+	while read -r _list_xargs_arg; do
+		_list_xargs_arg="$(_list_dec "$_list_xargs_arg"; echo :)"
+		_list_xargs_arg="${_list_xargs_arg%:}"
+		set -- "$@" "$_list_xargs_arg"
+	done
+	unset _list_xargs_arg
+	"$@"
+}
+list_pop() {
+	read -r _list_pop_line || return
+	inarg "$_list_pop_line" list_xargs printf '%s'
+}
+list_pack() {
+	[ $1 -ge 1 ] || return
+	_list_pack_spl=$1
+	while :; do
+		read -r line || break
+		set -- "$line"
+		i=$_list_pack_spl
+		while test $i -gt 1; do
+			read -r line || return
+			set -- "$@" "$line"
+			i=$((i - 1))
+		done
+		for line; do
+			printf '%s\n' "$line"
+		done | _list_enc || return
+	done
+}
+collect() {
+	_collect_fifo_lens="$(mktfifo)"
+	_collect_gen() {
+		i=0;
+		_collect_on() {
+			_name="$(inarg "$1" list_get 2; echo :)"; _name="${_name%:}"
+		}
+		{ while :; do
+			_name="$(list_pop && echo :)" || break
+			i=$((i+1)); (
+			_name="${_name%:}"
+			_name="$(inarg "$_name" list_get 2; echo :)"
+			_name="${_name%:}"
+			printf "%d %.0f\n" $i \
+			"$(if test -e "$_name"
+			then
+				ffprobe -loglevel 8 -of flat -show_entries format=duration "$_name" |
+					sed 's/^[^"]*"\([^"]*\)"$/\1/'
+			else
+				printf 'warn: "%s": file not found\n' "$_name" >&2
+				echo -1
+			fi)" ) &
+		done; wait; } | sort -n | sed 's/^[0-9]* *//' | while read line; do
+			list_mk "$line"
+		done
+	}
+	list_mk "$@" | list_pack 2 | _collect_gen > "$_collect_fifo_lens" &
+	_collect_fn() {
+		for _arg; do
+			_weight="$(inarg "$_arg" list_get 1; echo :)"; _weight="${_weight%:}"
+			_name="$(inarg "$_arg" list_get 2; echo :)"; _name="${_name%:}"
+			_len="$(list_pop <&3)" || exit
+			if [ "$_len" -ge 0 ]; then
+				_newf="$(list_mk "$_name" "$_weight" "$_len"; echo :)";
+				_newf="${_newf%:}"; list_mk "$_newf"
+			fi
+		done
+	}
+	list="$(list_mk "$@" | list_pack 2 |
+		list_xargs _collect_fn 3<"$_collect_fifo_lens")"
+	rm "$_collect_fifo_lens"
+	unset _collect_fifo_lens
+	unset _collect_fn
+	unset _collect_gen
+	if test $(inarg "$list" list_len) = 0; then
+		printf 'fatal: no music\n' >&2
+		exit 1
+	fi
+}
+if test -e /dev/urandom; then
+	rand() { echo $(head -c4 /dev/urandom | od -An -t u); }
+elif test -e /dev/random; then
+	rand() { echo $(head -c4 /dev/random | od -An -t u); }
+else
+	printf 'fatal: no random\n' >&2;
+	exit 1
+fi
+randn() {
+	(while true; do
+		if test -z $1; then printf 'randn: bad argument\n' >&2; exit 1; fi
+		_rand=$(rand || exit)
+		if ! [ $_rand -lt $(((1<<32) % $1)) ]; then
+			break;
+		fi
+	done
+	printf $(($_rand % $1)))
+}
+gen() {
+	(_f() {
+		_ff() {
+			printf '{\n\tname: %s\n\tweight: %sx\n\tlen: %ss\n}\n' "$@" >&2
+		}
+		for arg; do
+			inarg "$arg" list_xargs _ff
+		done
+	};inarg "$list" list_xargs _f)
+	_len="$(inarg "$list" list_len)"
+	echo count: $_len >&2
+	_maxll="$(_len_f() {
+		mll="$(inarg "$1" list_get 3)"
+		shift 1;
+		for arg; do
+			num="$(inarg "$arg" list_get 3)"
+			if [ "$num" -ge "$mll" ]; then
+				mll="$num"
+			fi
+		done
+		echo $mll
+	}; inarg "$list" list_xargs _len_f)"
+	echo maxlen: $_maxll >&2
+	_weight="$(wei=0
+		_onlist(){
+			for arg; do
+				_name="$(inarg "$arg" list_get 1; echo :)"; _name="${_name%:}"
+				_vwei="$(inarg "$arg" list_get 2; echo :)"; _vwei="${_vwei%:}"
+				_vlen="$(inarg "$arg" list_get 3; echo :)"; _vlen="${_vlen%:}"
+				prevwei=$wei;
+				wei=$((wei+(((10000 * _maxll) / _vlen) * _vwei)))
+				printf 'chance: %s\n' $((wei-prevwei)) >&2
+				_newf="$(list_mk "$_name" "$wei"; echo :)";
+				_newf="${_newf%:}"; list_mk "$_newf"
+			done
+		}
+		inarg "$list" list_xargs _onlist
+	echo :)"; _weight="${_weight%:}"
+	maxwei="$(_mw_fn(){
+		shift $(($# - 1))
+		inarg "$1" list_get 2
+	}; inarg "$_weight" list_xargs _mw_fn)"
+	set -- "" "" ""
+	while true; do
+		num=$(randn $maxwei || exit)
+		line="$(_fn(){
+			for arg; do
+				lnd="$arg"
+				wei="$(inarg "$arg" list_get 2)"
+				if [ $num -lt "$wei" ]; then break; fi
+			done
+			inarg "$lnd" list_get 1
+		}; inarg "$_weight" list_xargs _fn; echo :)"
+		line="${line%:}"
+		if  { test "$line" != "$3" || test $_len = 1; } &&
+			{ test "$line" != "$2" || test $(randn 100) -lt 9; } &&
+			{ test "$line" != "$1" || test $(randn 100) -lt 30; }
+		then
+			printf "%d\n%s\n" "$(printf '%s' "$line" | wc -c)" "$line" || exit
+			yes '' | tr '\n' ' ' | head -c 65536 # fill pipe quicker
+		fi
+		shift 1
+		set -- "$@" "$line"
+	done
+}
+gen2() {
+	gen | while read len; do
+		dd bs=$len count=1 2>/dev/null; printf '\0'
+		dd bs=1 count=1 2>/dev/null >/dev/null
+	done
+}
+play() {
+	_fifo_playl="$(mktfifo .m3u8)"
+	_fifo_script="$(mktfifo .lua)"
+{ cat <<'EOF'
+local f = assert(io.open("/dev/fd/4"))
+function spawn()
+	local sngi = assert(tonumber(f:read()))
+	local song = f:read(sngi)
+	f:read()
+	print("PLAYING: "..song)
+	mp.commandv("loadfile",song,"replace")
+	mp.set_property_bool("pause", false)
+end
+mp.observe_property("eof-reached", "bool", function(name, value)
+	if value then
+		spawn()
+	end
+end)
+spawn()
+EOF
+} >"$_fifo_script" &
+	gen >"$_fifo_playl" &
+	curpid=$$
+	clrn(){
+		rm "$_fifo_playl"
+		rm "$_fifo_script"
+	}
+	( while kill -0 $curpid 2>/dev/null; do sleep 0.05; done; clrn ) &
+	job="$(jobs -p | tail -n1)"
+	{
+		mpv --keep-open --no-video \
+			--volume=69 --script="$_fifo_script" --idle
+	} 4<"$_fifo_playl"
+	kill $job;
+	clrn
+}
+tell() { _tell_w_f() { for arg; do _name="$(inarg "$arg" list_get 1; echo :)"
+	_name="${_name%:}"; printf "%s\0" "$_name"; done }
+	inarg "$list" list_xargs _tell_w_f; }
+tell_w() { _tell_w_f() { for arg; do _name="$(inarg "$arg" list_get 2; echo :)"
+	_name="${_name%:}"; printf "%s\0" "$_name"; done }
+	inarg "$list" list_xargs _tell_w_f; }
+tell_l() { _tell_w_f() { for arg; do _name="$(inarg "$arg" list_get 3; echo :)"
+	_name="${_name%:}"; printf "%s\0" "$_name"; done }
+	inarg "$list" list_xargs _tell_w_f; }
+
+. "$2" || exit
+if test -z "$list"; then
+	printf 'fatal: bad playlist' >&2
+	exit 1
+fi
+
+  if test "$1" = tell; then tell;
+elif test "$1" = tell_w; then tell_w;
+elif test "$1" = tell_l; then tell_l;
+elif test "$1" = gen; then gen2;
+elif test "$1" = play; then play;
+else printf "play6: invalid argument\n" >&2; exit 1
+fi