# coding: utf-8
from __future__ import division, print_function, unicode_literals

import hashlib
import io
import logging
import os
import re
import shlex
import shutil
import subprocess as sp
import tempfile
import threading
import time

from queue import Queue

from .__init__ import ANYWIN, PY2, TYPE_CHECKING, unicode
from .authsrv import VFS
from .bos import bos
from .mtag import (
    HAVE_FFMPEG,
    HAVE_FFPROBE,
    TH_BWRAP,
    au_unpk,
    bwrap,
    bwrap_fail,
    ffprobe,
    have_ff,
)
from .util import BytesIO  # type: ignore
from .util import (
    FFMPEG_URL,
    SCWD,
    VF_CAREFUL,
    Cooldown,
    Daemon,
    afsenc,
    atomic_move,
    fsenc,
    min_ex,
    runcmd,
    statdir,
    ub64enc,
    vsplit,
    wunlink,
)

if True:  # pylint: disable=using-constant-test
    from typing import Any, Callable, Optional, Union

if TYPE_CHECKING:
    from .svchub import SvcHub

if PY2:
    range = xrange  # type: ignore

HAVE_PIL = False
HAVE_PILF = False
H_PIL_HEIF = False
H_PIL_AVIF = False
H_PIL_WEBP = False
H_PIL_JXL = False

TH_CH = {"j": "jpg", "p": "png", "w": "webp", "x": "jxl"}

EXTS_TH = set(["jpg", "webp", "jxl", "png"])
EXTS_AC = set(["opus", "owa", "caf", "mp3", "flac", "wav"])
EXTS_SPEC_SAFE = set("aif aiff flac mp3 opus wav".split())

PTN_TS = re.compile("^-?[0-9a-f]{8,10}$")

# for n in {1..100}; do rm -rf /home/ed/Pictures/wp/.hist/th/ ; python3 -m copyparty -qv /home/ed/Pictures/wp/::r --th-no-webp --th-qv $n --th-dec pil >/dev/null 2>&1 & p=$!; printf '\033[A\033[J%3d ' $n; while true; do sleep 0.1; curl -s 127.1:3923 >/dev/null && break; done; curl -s '127.1:3923/?tar=j' >/dev/null ; cat /home/ed/Pictures/wp/.hist/th/1n/bs/1nBsjDetfie1iDq3y2D4YzF5/*.* | wc -c; kill $p; wait >/dev/null 2>&1; done
# filesize-equivalent, not quality (ff looks much shittier)
FF_JPG_Q = {
    0: b"30",  # 0
    1: b"30",  # 5
    2: b"30",  # 10
    3: b"30",  # 15
    4: b"28",  # 20
    5: b"21",  # 25
    6: b"17",  # 30
    7: b"15",  # 35
    8: b"13",  # 40
    9: b"12",  # 45
    10: b"11",  # 50
    11: b"10",  # 55
    12: b"9",  # 60
    13: b"8",  # 65
    14: b"7",  # 70
    15: b"6",  # 75
    16: b"5",  # 80
    17: b"4",  # 85
    18: b"3",  # 90
    19: b"2",  # 95
    20: b"2",  # 100
}
# FF_JPG_Q = {xn: ("%d" % (xn,)).encode("ascii") for xn in range(2, 33)}
VIPS_JPG_Q = {
    0: 4,  # 0
    1: 7,  # 5
    2: 12,  # 10
    3: 17,  # 15
    4: 22,  # 20
    5: 27,  # 25
    6: 32,  # 30
    7: 37,  # 35
    8: 42,  # 40
    9: 47,  # 45
    10: 52,  # 50
    11: 56,  # 55
    12: 61,  # 60
    13: 66,  # 65
    14: 71,  # 70
    15: 75,  # 75
    16: 80,  # 80
    17: 85,  # 85
    18: 89,  # 90 (vips explodes past this point)
    19: 91,  # 95
    20: 97,  # 100
}


try:
    if os.environ.get("PRTY_NO_PIL"):
        raise Exception()

    from PIL import ExifTags, Image, ImageFont, ImageOps

    HAVE_PIL = True
    try:
        if os.environ.get("PRTY_NO_PILF"):
            raise Exception()

        ImageFont.load_default(size=16)
        HAVE_PILF = True
    except:
        pass

    try:
        if os.environ.get("PRTY_NO_PIL_WEBP"):
            raise Exception()

        Image.new("RGB", (2, 2)).save(BytesIO(), format="webp")
        H_PIL_WEBP = True
    except:
        pass

    try:
        if os.environ.get("PRTY_NO_PIL_JXL"):
            raise Exception()

        try:
            import pillow_jxl
        except ImportError:
            pass

        Image.new("RGB", (2, 2)).save(BytesIO(), format="jxl")
        H_PIL_JXL = True
    except:
        pass

    try:
        if os.environ.get("PRTY_NO_PIL_HEIF"):
            raise Exception()

        try:
            from pillow_heif import register_heif_opener
        except ImportError:
            from pyheif_pillow_opener import register_heif_opener

        register_heif_opener()
        H_PIL_HEIF = True
    except:
        pass

    try:
        if os.environ.get("PRTY_NO_PIL_AVIF"):
            raise Exception()

        if ".avif" in Image.registered_extensions():
            H_PIL_AVIF = True
            raise Exception()

        import pillow_avif  # noqa: F401  # pylint: disable=unused-import

        H_PIL_AVIF = True
    except:
        pass

    logging.getLogger("PIL").setLevel(logging.WARNING)
except:
    pass

try:
    if os.environ.get("PRTY_NO_VIPS"):
        raise ImportError()

    if "VIPS_CONCURRENCY" not in os.environ:
        # reduces glibc RAM usage from 4.7 to 3.5 GiB ...yep, still bonkers
        os.environ["VIPS_CONCURRENCY"] = "1"

    HAVE_VIPS = True
    import pyvips

    pyvips.cache_set_max(0)
    logging.getLogger("pyvips").setLevel(logging.WARNING)
except Exception as e:
    HAVE_VIPS = False
    if not isinstance(e, ImportError):
        logging.warning("libvips found, but failed to load: " + str(e))


PRTY_NO_RAW = os.environ.get("PRTY_NO_RAW")
PRTY_NO_RAWPY = PRTY_NO_RAW or os.environ.get("PRTY_NO_RAWPY")
PRTY_NO_DCRAW = PRTY_NO_RAW or os.environ.get("PRTY_NO_DCRAW")
try:
    if PRTY_NO_RAWPY:
        raise Exception()

    HAVE_RAWPY = True
    import rawpy

    logging.getLogger("rawpy").setLevel(logging.WARNING)
except:
    HAVE_RAWPY = False


HAVE_DCRAW = not PRTY_NO_DCRAW and have_ff("dcraw_emu")


th_dir_cache = {}


def thumb_path(histpath: str, rem: str, mtime: float, fmt: str, ffa: set[str]) -> str:
    # base16 = 16 = 256
    # b64-lc = 38 = 1444
    # base64 = 64 = 4096
    rd, fn = vsplit(rem)
    if not rd:
        rd = "\ntop"

    dcache = th_dir_cache
    rd_key = rd + "\n" + fmt
    rd = dcache.get(rd_key)
    if not rd:
        h = hashlib.sha512(afsenc(rd_key)).digest()
        b64 = ub64enc(h).decode("ascii")[:24]
        rd = ("%s/%s/" % (b64[:2], b64[2:4])).lower() + b64
        if len(dcache) > 9001:
            dcache.clear()
        dcache[rd_key] = rd

    # could keep original filenames but this is safer re pathlen
    h = hashlib.sha512(afsenc(fn)).digest()
    fn = ub64enc(h).decode("ascii")[:24]

    if fmt in EXTS_AC:
        cat = "ac"
    else:
        fmt = TH_CH[fmt[:1]]
        cat = "th"

    return "%s/%s/%s/%s.%x.%s" % (histpath, cat, rd, fn, int(mtime), fmt)


class ThumbSrv(object):
    def __init__(self, hub: "SvcHub") -> None:
        self.hub = hub
        self.asrv = hub.asrv
        self.args = hub.args
        self.log_func = hub.log

        self.log = self._log
        self.nextlog = 0

        self.poke_cd = Cooldown(self.args.th_poke) if self.args.th_poke else None

        self.mutex = threading.Lock()
        self.busy: dict[str, list[threading.Condition]] = {}
        self.untemp: dict[str, list[str]] = {}
        self.ram: dict[str, float] = {}
        self.memcond = threading.Condition(self.mutex)
        self.stopping = False
        self.rm_nullthumbs = True  # forget failed conversions on startup
        self.nthr = max(1, self.args.th_mt)

        self.exts_spec_unsafe = set(self.args.th_spec_cnv.split(","))

        # libvips can easily gobble up 4 GiB of RAM when generating JXL thumbnails on glibc so let's not
        self.vips_jxl = False
        if HAVE_VIPS and self.args.th_vips_jxl == 2:
            self.vips_jxl = True
        elif HAVE_VIPS and self.args.th_vips_jxl == 1:
            try:
                with open("/proc/self/maps", "rb") as f:
                    zb = f.read()
                self.vips_jxl = b"/ld-musl-" in zb and b"mimalloc" not in zb
            except:
                pass

        self.q: Queue[Optional[tuple[str, str, str, VFS]]] = Queue(self.nthr * 4)
        for n in range(self.nthr):
            Daemon(self.worker, "thumb-{}-{}".format(n, self.nthr))

        want_ff = not self.args.no_vthumb or not self.args.no_athumb
        if want_ff and (not HAVE_FFMPEG or not HAVE_FFPROBE):
            missing = []
            if not HAVE_FFMPEG:
                missing.append("FFmpeg")

            if not HAVE_FFPROBE:
                missing.append("FFprobe")

            msg = "cannot create audio/video thumbnails because some of the required programs are not available: "
            msg += ", ".join(missing)
            self.log(msg, c=3)
            if ANYWIN and self.args.no_acode:
                self.log("download FFmpeg to fix it:\033[0m " + FFMPEG_URL, 3)

        self.conv_raw = self._conv_rawpy if HAVE_RAWPY else self._conv_dcraw

        if self.args.th_clean:
            Daemon(self.cleaner, "thumb.cln")

        (
            self.fmt_pil,
            self.fmt_vips,
            self.fmt_raw,
            self.fmt_ffi,
            self.fmt_ffv,
            self.fmt_ffa,
        ) = [
            set(y.split(","))
            for y in [
                self.args.th_r_pil,
                self.args.th_r_vips,
                self.args.th_r_raw,
                self.args.th_r_ffi,
                self.args.th_r_ffv,
                self.args.th_r_ffa,
            ]
        ]

        if not H_PIL_HEIF:
            for f in "heif heifs heic heics".split(" "):
                self.fmt_pil.discard(f)

        if not H_PIL_AVIF:
            for f in "avif avifs".split(" "):
                self.fmt_pil.discard(f)

        if not H_PIL_WEBP:
            for f in "webp".split(" "):
                self.fmt_pil.discard(f)

        if not H_PIL_JXL:
            for f in "jxl".split(" "):
                self.fmt_pil.discard(f)

        self.thumbable: set[str] = set()
        self._build_thumbable()

    def _build_thumbable(self) -> None:
        self.thumbable.clear()

        if "pil" in self.args.th_dec:
            self.thumbable |= self.fmt_pil

        if "vips" in self.args.th_dec:
            self.thumbable |= self.fmt_vips

        if "raw" in self.args.th_dec:
            self.thumbable |= self.fmt_raw

        if "ff" in self.args.th_dec:
            for zss in [self.fmt_ffi, self.fmt_ffv, self.fmt_ffa]:
                self.thumbable |= zss

    def _log(self, msg: str, c: Union[int, str] = 0) -> None:
        self.log_func("thumb", msg, c)

    def _slog(self, msg: str, c: Union[int, str] = 0) -> None:
        now = time.time()
        if c in (0, 6) and now < self.nextlog:
            return
        self.nextlog = now + self.args.th_pre_rl
        self.log_func("thumb", msg, c)

    def shutdown(self) -> None:
        self.stopping = True
        Daemon(self._fire_sentinels, "thumbstopper")

    def _fire_sentinels(self):
        for _ in range(self.nthr):
            self.q.put(None)

    def stopped(self) -> bool:
        with self.mutex:
            return not self.nthr

    def getres(self, vn: VFS, fmt: str) -> tuple[int, int]:
        mul = 3 if "3" in fmt else 1
        w, h = vn.flags["thsize"].split("x")
        return int(w) * mul, int(h) * mul

    def get(self, ptop: str, rem: str, mtime: float, fmt: str) -> Optional[str]:
        histpath = self.asrv.vfs.histtab.get(ptop)
        if not histpath:
            self.log("no histpath for %r" % (ptop,))
            return None

        tpath = thumb_path(histpath, rem, mtime, fmt, self.fmt_ffa)
        abspath = os.path.join(ptop, rem)
        cond = threading.Condition(self.mutex)
        do_conv = False
        with self.mutex:
            try:
                self.busy[tpath].append(cond)
                self.log("joined waiting room for %r" % (tpath,))
            except:
                thdir = os.path.dirname(tpath)
                chmod = bos.MKD_700 if self.args.free_umask else bos.MKD_755
                bos.makedirs(os.path.join(thdir, "w"), vf=chmod)

                inf_path = os.path.join(thdir, "dir.txt")
                if not bos.path.exists(inf_path):
                    with open(inf_path, "wb") as f:
                        f.write(afsenc(os.path.dirname(abspath)))
                    self.writevolcfg(histpath)

                self.busy[tpath] = [cond]
                do_conv = True

        if do_conv:
            allvols = list(self.asrv.vfs.all_vols.values())
            vn = next((x for x in allvols if x.realpath == ptop), None)
            if not vn:
                self.log("ptop %r not in %s" % (ptop, allvols), 3)
                vn = self.asrv.vfs.all_aps[0][1][0]

            self.q.put((abspath, tpath, fmt, vn))
            self.log("conv %r :%s \033[0m%r" % (tpath, fmt, abspath), 6)

        while not self.stopping:
            with self.mutex:
                if tpath not in self.busy:
                    break

            with cond:
                cond.wait(3)

        try:
            st = bos.stat(tpath)
            if st.st_size:
                self.poke(tpath)
                return tpath
        except:
            pass

        return None

    def _rebuild_thumbable(self) -> None:
        self._build_thumbable()
        self.hub.broker.say("httpsrv.set_th_cfg", self.getcfg(), (self.args.th_no_jxl,))

    def getcfg(self) -> dict[str, set[str]]:
        return {
            "thumbable": self.thumbable,
            "pil": self.fmt_pil,
            "vips": self.fmt_vips,
            "raw": self.fmt_raw,
            "ffi": self.fmt_ffi,
            "ffv": self.fmt_ffv,
            "ffa": self.fmt_ffa,
        }

    def volcfgi(self, vn: VFS) -> str:
        ret = []
        zs = "th_dec th_no_webp th_no_jpg"
        for zs in zs.split(" "):
            ret.append("%s(%s)\n" % (zs, getattr(self.args, zs)))
        zs = "th_spec_fl"
        for zs in zs.split(" "):
            v = getattr(self.args, zs)
            if v:
                ret.append("%s(%s)\n" % (zs, v))
        zs = "th_qv th_qvx thsize th_spec_p convt"
        for zs in zs.split(" "):
            ret.append("%s(%s)\n" % (zs, vn.flags.get(zs)))
        return "".join(ret)

    def volcfga(self, vn: VFS) -> str:
        ret = []
        zs = "q_opus q_mp3"
        for zs in zs.split(" "):
            ret.append("%s(%s)\n" % (zs, getattr(self.args, zs)))
        zs = "aconvt"
        for zs in zs.split(" "):
            ret.append("%s(%s)\n" % (zs, vn.flags.get(zs)))
        return "".join(ret)

    def writevolcfg(self, histpath: str) -> None:
        try:
            bos.stat(os.path.join(histpath, "th", "cfg.txt"))
            bos.stat(os.path.join(histpath, "ac", "cfg.txt"))
            return
        except:
            pass
        cfgi = cfga = ""
        for vn in self.asrv.vfs.all_vols.values():
            if vn.histpath == histpath:
                cfgi = self.volcfgi(vn)
                cfga = self.volcfga(vn)
                break
        t = "writing thumbnailer-config %d,%d to %s"
        self.log(t % (len(cfgi), len(cfga), histpath))
        chmod = bos.MKD_700 if self.args.free_umask else bos.MKD_755
        for cfg, cat in ((cfgi, "th"), (cfga, "ac")):
            bos.makedirs(os.path.join(histpath, cat), vf=chmod)
            with open(os.path.join(histpath, cat, "cfg.txt"), "wb") as f:
                f.write(cfg.encode("utf-8"))

    def wait4ram(self, need: float, ttpath: str) -> None:
        ram = self.args.th_ram_max
        if need > ram * 0.99:
            t = "file too big; need %.2f GiB RAM, but --th-ram-max is only %.1f"
            raise Exception(t % (need, ram))

        while True:
            with self.mutex:
                used = sum([v for k, v in self.ram.items() if k != ttpath]) + need
                if used < ram:
                    # self.log("XXX self.ram: %s" % (self.ram,), 5)
                    self.ram[ttpath] = need
                    return
            with self.memcond:
                # self.log("at RAM limit; used %.2f GiB, need %.2f more" % (used-need, need), 1)
                self.memcond.wait(3)

    def worker(self) -> None:
        while not self.stopping:
            task = self.q.get()
            if not task:
                break

            abspath, tpath, fmt, vn = task
            ext = abspath.split(".")[-1].lower()
            png_ok = False
            funs = []

            if ext in self.args.au_unpk:
                ap_unpk = au_unpk(self.log, self.args.au_unpk, abspath, vn)
            else:
                ap_unpk = abspath

            if ap_unpk and not bos.path.exists(tpath):
                tex = tpath.rsplit(".", 1)[-1]
                want_mp3 = tex == "mp3"
                want_opus = tex in ("opus", "owa", "caf")
                want_flac = tex == "flac"
                want_wav = tex == "wav"
                want_png = tex == "png"
                want_au = want_mp3 or want_opus or want_flac or want_wav
                for lib in self.args.th_dec:
                    can_au = lib == "ff" and (
                        ext in self.fmt_ffa or ext in self.fmt_ffv
                    )

                    if lib == "pil" and ext in self.fmt_pil and tex in self.fmt_pil:
                        funs.append(self.conv_pil)
                    elif (
                        lib == "vips"
                        and ext in self.fmt_vips
                        and (tex != "jxl" or self.vips_jxl)
                    ):
                        funs.append(self.conv_vips)
                    elif lib == "raw" and ext in self.fmt_raw:
                        funs.append(self.conv_raw)
                    elif can_au and (want_png or want_au):
                        if want_opus:
                            funs.append(self.conv_opus)
                        elif want_mp3:
                            funs.append(self.conv_mp3)
                        elif want_flac:
                            funs.append(self.conv_flac)
                        elif want_wav:
                            funs.append(self.conv_wav)
                        elif want_png:
                            funs.append(self.conv_waves)
                            png_ok = True
                    elif lib == "ff" and (ext in self.fmt_ffi or ext in self.fmt_ffv):
                        funs.append(self.conv_ffmpeg)
                    elif lib == "ff" and ext in self.fmt_ffa and not want_au:
                        funs.append(self.conv_spec)

            tdir, tfn = os.path.split(tpath)
            ttpath = os.path.join(tdir, "w", tfn)
            try:
                wunlink(self.log, ttpath, vn.flags)
            except:
                pass

            conv_ok = False
            for fun in funs:
                try:
                    if not png_ok and tpath.endswith(".png"):
                        raise Exception("png only allowed for waveforms")

                    fun(ap_unpk, ttpath, fmt, vn)
                    conv_ok = True
                    break
                except Exception as ex:
                    r321 = getattr(ex, "returncode", 0) == 321
                    msg = "%s could not create thumbnail of %r\n%s"
                    msg = msg % (fun.__name__, abspath, ex if r321 else min_ex())
                    c: Union[str, int] = 1 if "<Signals.SIG" in msg else "90"
                    self.log(msg, c)
                    if not r321:
                        if fun == funs[-1]:
                            try:
                                with open(ttpath, "wb") as _:
                                    pass
                            except Exception as ex:
                                t = "failed to create the file [%s]: %r"
                                self.log(t % (ttpath, ex), 3)
                    else:
                        # ffmpeg may spawn empty files on windows
                        try:
                            wunlink(self.log, ttpath, vn.flags)
                        except:
                            pass

            if abspath != ap_unpk and ap_unpk:
                wunlink(self.log, ap_unpk, vn.flags)

            try:
                atomic_move(self.log, ttpath, tpath, vn.flags)
            except Exception as ex:
                if conv_ok and not os.path.exists(tpath):
                    t = "failed to move  [%s]  to  [%s]:  %r"
                    self.log(t % (ttpath, tpath, ex), 3)
                elif not conv_ok:
                    try:
                        open(tpath, "ab").close()
                    except:
                        pass

            untemp = []
            with self.mutex:
                subs = self.busy[tpath]
                del self.busy[tpath]
                self.ram.pop(ttpath, None)
                untemp = self.untemp.pop(ttpath, None) or []

            for ap in untemp:
                try:
                    wunlink(self.log, ap, VF_CAREFUL)
                except:
                    pass

            for x in subs:
                with x:
                    x.notify_all()

            with self.memcond:
                self.memcond.notify_all()

        with self.mutex:
            self.nthr -= 1

    def fancy_pillow(self, im: "Image.Image", fmt: str, vn: VFS) -> "Image.Image":
        # exif_transpose is expensive (loads full image + unconditional copy)
        res = self.getres(vn, fmt)
        r = max(*res) * 2
        im.thumbnail((r, r), resample=Image.LANCZOS)
        try:
            k = next(k for k, v in ExifTags.TAGS.items() if v == "Orientation")
            exif = im.getexif()
            rot = int(exif[k])
            del exif[k]
        except:
            rot = 1

        rots = {8: Image.ROTATE_90, 3: Image.ROTATE_180, 6: Image.ROTATE_270}
        if rot in rots:
            im = im.transpose(rots[rot])

        if "f" in fmt:
            im.thumbnail(res, resample=Image.LANCZOS)
        else:
            iw, ih = im.size
            dw, dh = res
            res = (min(iw, dw), min(ih, dh))
            im = ImageOps.fit(im, res, method=Image.LANCZOS)

        return im

    def conv_image_pil(self, im: "Image.Image", tpath: str, fmt: str, vn: VFS) -> None:
        try:
            im = self.fancy_pillow(im, fmt, vn)
        except Exception as ex:
            self.log("fancy_pillow {}".format(ex), "90")
            im.thumbnail(self.getres(vn, fmt))

        fmts = ["RGB", "L"]
        zs = "th_qvx" if tpath.endswith(".jxl") else "th_qv"
        args = {"quality": vn.flags[zs]}

        if tpath.endswith(".webp"):
            # quality 80 = pillow-default
            # quality 75 = ffmpeg-default
            # method 0 = pillow-default, fast
            # method 4 = ffmpeg-default
            # method 6 = max, slow
            fmts.extend(("RGBA", "LA"))
            args["method"] = 6
        else:
            # default q = 75
            args["progressive"] = True

        if im.mode not in fmts:
            # print("conv {}".format(im.mode))
            im = im.convert("RGB")

        im.save(tpath, **args)

    def conv_pil(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        self.wait4ram(0.2, tpath)
        with Image.open(fsenc(abspath)) as im:
            self.conv_image_pil(im, tpath, fmt, vn)

    def conv_image_vips(
        self, loader: "Callable[[int, dict], Any]", tpath: str, fmt: str, vn: VFS
    ) -> None:
        crops = ["centre", "none"]
        if "f" in fmt:
            crops = ["none"]

        w, h = self.getres(vn, fmt)
        kw = {"height": h, "size": "down", "intent": "relative"}

        img = None
        for c in crops:
            try:
                kw["crop"] = c
                img = loader(w, kw)
                break
            except:
                if c == crops[-1]:
                    raise

        assert img  # type: ignore  # !rm
        args = {}
        qv = vn.flags["th_qv"]
        if tpath.endswith("jpg"):
            qv = VIPS_JPG_Q[qv // 5]
            args["optimize_coding"] = True
        elif tpath.endswith("jxl"):
            qv = vn.flags["th_qvx"]
            # args["effort"] = 8
            #  `- not worth it; twice as slow, size drops 12%, no visual improvement unlike ffmpeg
        img.write_to_file(tpath, Q=qv, strip=True, **args)
        img.invalidate()

    def conv_vips(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        self.wait4ram(0.2, tpath)

        def _loader(w: int, kw: dict) -> Any:
            return pyvips.Image.thumbnail(abspath, w, **kw)

        self.conv_image_vips(_loader, tpath, fmt, vn)

    def _conv_dcraw(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        self.wait4ram(0.6, tpath)
        bap = fsenc(abspath)
        # fmt: off
        cmd = bwrap(HAVE_DCRAW[0], bap, b"") + [
            b"-h",  # halfsize
            b"-o", b"1",  # srgb
            b"-s", b"0",  # first frame
            b"-Z", b"-",  # to stdout
            bap,
        ]
        # fmt: on
        p = sp.Popen(cmd, stdout=sp.PIPE, cwd=SCWD)
        try:
            if HAVE_PIL:
                self.conv_image_pil(Image.open(p.stdout), tpath, fmt, vn)
            elif HAVE_VIPS:
                ppm, _ = p.communicate(timeout=vn.flags["convt"])

                def _loader(w: int, kw: dict) -> Any:
                    return pyvips.Image.thumbnail_buffer(ppm, w, **kw)

                self.conv_image_vips(_loader, tpath, fmt, vn)
            else:
                raise Exception(
                    "either pil or vips is needed to process embedded bitmap thumbnails in raw files"
                )
        finally:
            if p and p.poll() is None:
                p.kill()

    def _conv_rawpy(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        self.wait4ram(0.6, tpath)
        with rawpy.imread(abspath) as raw:
            thumb = raw.extract_thumb()
        if thumb.format == rawpy.ThumbFormat.JPEG and tpath.endswith(".jpg"):
            # if we have a jpg thumbnail and no webp output is available,
            # just write the jpg directly (it'll be the wrong size, but it's fast)
            with open(tpath, "wb") as f:
                f.write(thumb.data)
        if HAVE_VIPS:

            def _loader(w: int, kw: dict) -> Any:
                if thumb.format == rawpy.ThumbFormat.BITMAP:
                    img = pyvips.Image.new_from_array(thumb.data, interpretation="rgb")
                    return img.thumbnail_image(w, **kw)
                else:
                    return pyvips.Image.thumbnail_buffer(thumb.data, w, **kw)

            self.conv_image_vips(_loader, tpath, fmt, vn)
        elif HAVE_PIL:
            if thumb.format == rawpy.ThumbFormat.BITMAP:
                im = Image.fromarray(thumb.data, "RGB")
            else:
                im = Image.open(io.BytesIO(thumb.data))
            self.conv_image_pil(im, tpath, fmt, vn)
        else:
            raise Exception(
                "either pil or vips is needed to process embedded bitmap thumbnails in raw files"
            )

    def conv_ffmpeg(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        self.wait4ram(0.2, tpath)
        ret, raw, strms, ctnr = ffprobe(abspath, int(vn.flags["convt"] / 2))
        if not ret:
            return

        if "vc" not in ret and "ac" in ret:
            # audio in a video trenchcoat
            return self.conv_spec(abspath, tpath, fmt, vn)

        for strm in strms:
            if (
                strm.get("codec_type") == "video"
                and strm.get("DISPOSITION:attached_pic") == "1"
            ):
                return self.conv_emb_cv(abspath, tpath, fmt, vn, strm)

        ext = abspath.rsplit(".")[-1].lower()
        if ext in ["h264", "h265"] or ext in self.fmt_ffi:
            seek: list[bytes] = []
        else:
            dur = ret[".dur"][1] if ".dur" in ret else 4
            seek = [b"-ss", "{:.0f}".format(dur / 3).encode("utf-8")]

        self._ffmpeg_im(abspath, tpath, fmt, vn, seek, b"0:v:0")

    def _ffmpeg_im(
        self,
        abspath: str,
        tpath: str,
        fmt: str,
        vn: VFS,
        seek: list[bytes],
        imap: bytes,
    ) -> None:
        scale = "scale={0}:{1}:force_original_aspect_ratio="
        if "f" in fmt:
            scale += "decrease,setsar=1:1"
        else:
            scale += "increase,crop={0}:{1},setsar=1:1"

        res = self.getres(vn, fmt)
        bscale = scale.format(*list(res)).encode("utf-8")
        bap_in = fsenc(abspath)
        bap_out = fsenc(tpath)
        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner"
        ] + seek + [
            b"-i", bap_in,
            b"-map", imap,
            b"-vf", bscale,
            b"-frames:v", b"1",
            b"-metadata:s:v:0", b"rotate=0",
        ]
        # fmt: on

        self._ffmpeg_im_o(bap_out, vn, cmd)

    def _ffmpeg_im_o(self, tpath: bytes, vn: VFS, cmd: list[bytes]) -> None:
        if tpath.endswith(b".jpg"):
            cmd += [
                b"-q:v",
                FF_JPG_Q[vn.flags["th_qv"] // 5],  # default=??
            ]
        elif tpath.endswith(b".jxl"):
            cmd += [
                b"-q:v",
                unicode(vn.flags["th_qvx"]).encode("ascii"),  # default=??
                b"-effort:v",
                b"7",  # default=7, 1=fast, 9=max, 9~=8 but slower
            ]
        else:
            cmd += [
                b"-q:v",
                unicode(vn.flags["th_qv"]).encode("ascii"),  # default=75
                b"-compression_level:v",
                b"6",  # default=4, 0=fast, 6=max
            ]

        cmd.append(tpath)
        self._run_ff(cmd, vn, "convt")

    def _run_ff(self, cmd: list[bytes], vn: VFS, kto: str, oom: int = 400) -> None:
        # self.log((b" ".join(cmd)).decode("utf-8"))
        ret, _, serr = runcmd(cmd, cwd=SCWD, timeout=vn.flags[kto], nice=True, oom=oom)
        if not ret:
            return

        if TH_BWRAP:
            bwrap_fail(serr)

        c: Union[str, int] = "90"
        t = "FFmpeg failed (probably a corrupt file):\n"

        if "but no decoder found for: hevc" in serr:
            t = "thumbnail cannot be created due to legal reasons; https://github.com/9001/copyparty/blob/hovudstraum/docs/bad-codecs.md \033[0;90m\n"
            ret = 321
            c = 3

        elif cmd[-1].lower().endswith(b".jxl") and (
            "Error selecting an encoder" in serr
            or "find a suitable output format" in serr
            or "Automatic encoder selection failed" in serr
            or "Default encoder for format webp" in serr
            or "Unrecognized option 'effort:v" in serr
            or "Please choose an encoder manually" in serr
        ):
            self.args.th_no_jxl = True
            self.fmt_ffi.discard("jxl")
            self.fmt_ffv.discard("jxl")
            self._rebuild_thumbable()
            t = "FFmpeg failed because it was compiled without jpegxl; enabling --th-no-jxl to force webp output:\n"
            ret = 321
            c = 1

        elif (
            (not self.args.th_ff_jpg or time.time() - int(self.args.th_ff_jpg) < 60)
            and cmd[-1].lower().endswith(b".webp")
            and (
                "Error selecting an encoder" in serr
                or "Automatic encoder selection failed" in serr
                or "Default encoder for format webp" in serr
                or "Please choose an encoder manually" in serr
            )
        ):
            self.args.th_ff_jpg = time.time()
            t = "FFmpeg failed because it was compiled without libwebp; enabling --th-ff-jpg to force jpeg output:\n"
            ret = 321
            c = 1

        elif (
            not self.args.th_ff_swr or time.time() - int(self.args.th_ff_swr) < 60
        ) and (
            "Requested resampling engine is unavailable" in serr
            or "output pad on Parsed_aresample_" in serr
        ):
            self.args.th_ff_swr = time.time()
            t = "FFmpeg failed because it was compiled without libsox; enabling --th-ff-swr to force swr resampling:\n"
            ret = 321
            c = 1

        lines = serr.strip("\n").split("\n")
        if len(lines) > 50:
            lines = lines[:25] + ["[...]"] + lines[-25:]

        txt = "\n".join(["ff: " + unicode(x) for x in lines])
        if len(txt) > 5000:
            txt = txt[:2500] + "...\nff: [...]\nff: ..." + txt[-2500:]

        try:
            zs = shlex.join([x.decode("utf-8", "replace") for x in cmd])
        except:
            zs = "'" + (b"' '".join(cmd)).decode("utf-8", "replace") + "'"

        self.log("%scmd: %s\n%s" % (t, zs, txt), c=c)
        raise sp.CalledProcessError(ret, (cmd[0], b"...", cmd[-1]))

    def conv_waves(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        ret, _, _, _ = ffprobe(abspath, int(vn.flags["convt"] / 2))
        if "ac" not in ret:
            raise Exception("not audio")

        # jt_versi.xm: 405M/839s
        dur = ret[".dur"][1] if ".dur" in ret else 300
        need = 0.2 + dur / 3000
        speedup = b""
        if need > self.args.th_ram_max * 0.7:
            self.log("waves too big (need %.2f GiB); trying to optimize" % (need,))
            need = 0.2 + dur / 4200  # only helps about this much...
            speedup = b"aresample=8000,"
        if need > self.args.th_ram_max * 0.96:
            raise Exception("file too big; cannot waves")

        self.wait4ram(need, tpath)

        flt = b"[0:a:0]" + speedup
        flt += (
            b"compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2"
            b",volume=2"
            b",showwavespic=s=2048x64:colors=white"
            b",convolution=1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 -1 1 -1 5 -1 1 -1 1"  # idk what im doing but it looks ok
        )
        bap_in = fsenc(abspath)
        bap_out = fsenc(tpath)

        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner",
            b"-i", bap_in,
            b"-filter_complex", flt,
            b"-frames:v", b"1",
        ]
        # fmt: on

        cmd.append(bap_out)
        self._run_ff(cmd, vn, "convt")

        if "pngquant" in vn.flags:
            wtpath = tpath + ".png"
            cmd = [
                b"pngquant",
                b"--strip",
                b"--nofs",
                b"--output",
                fsenc(wtpath),
                fsenc(tpath),
            ]
            ret = runcmd(cmd, timeout=vn.flags["convt"], nice=True, oom=400)[0]
            if ret:
                try:
                    wunlink(self.log, wtpath, vn.flags)
                except:
                    pass
            else:
                atomic_move(self.log, wtpath, tpath, vn.flags)

    def conv_emb_cv(
        self, abspath: str, tpath: str, fmt: str, vn: VFS, strm: dict[str, Any]
    ) -> None:
        self.wait4ram(0.2, tpath)
        self._ffmpeg_im(
            abspath, tpath, fmt, vn, [], b"0:" + strm["index"].encode("ascii")
        )

    def conv_spec(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        ret, raw, strms, ctnr = ffprobe(abspath, int(vn.flags["convt"] / 2))
        if "ac" not in ret:
            raise Exception("not audio")

        want_spec = vn.flags.get("th_spec_p", 1)
        if want_spec < 2:
            for strm in strms:
                if (
                    strm.get("codec_type") == "video"
                    and strm.get("DISPOSITION:attached_pic") == "1"
                ):
                    return self.conv_emb_cv(abspath, tpath, fmt, vn, strm)

        if not want_spec:
            raise Exception("spectrograms forbidden by volflag")

        fext = abspath.split(".")[-1].lower()

        # https://trac.ffmpeg.org/ticket/10797
        # expect 1 GiB every 600 seconds when duration is tricky;
        # simple filetypes are generally safer so let's special-case those
        coeff = 1800 if fext in EXTS_SPEC_SAFE else 600
        dur = ret[".dur"][1] if ".dur" in ret else 900
        need = 0.2 + dur / coeff
        self.wait4ram(need, tpath)

        infile = abspath
        if dur >= 900 or fext in self.exts_spec_unsafe:
            with tempfile.NamedTemporaryFile(suffix=".spec.flac", delete=False) as f:
                f.write(b"h")
                infile = f.name
                try:
                    self.untemp[tpath].append(infile)
                except:
                    self.untemp[tpath] = [infile]

            bap_in = fsenc(abspath)
            bap_out = fsenc(infile)

            # fmt: off
            cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
                b"-nostdin",
                b"-v", b"error",
                b"-hide_banner",
                b"-i", bap_in,
                b"-map", b"0:a:0",
                b"-ac", b"1",
                b"-ar", b"48000",
                b"-sample_fmt", b"s16",
                b"-t", b"900",
                b"-y", bap_out,
            ]
            # fmt: on
            self._run_ff(cmd, vn, "convt")

        fscale = ":fscale=log" if self.args.th_spec_fl else ""

        fc = "[0:a:0]aresample=48000{},showspectrumpic=s="
        if "3" in fmt:
            fc += "1280x1024%s,crop=1420:1056:70:48[o]" % fscale
        else:
            fc += "640x512%s,crop=780:544:70:48[o]" % fscale

        if self.args.th_ff_swr:
            fco = ":filter_size=128:cutoff=0.877"
        else:
            fco = ":resampler=soxr"

        fc = fc.format(fco)

        bap_in = fsenc(infile)
        bap_out = fsenc(tpath)

        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner",
            b"-i", bap_in,
            b"-filter_complex", fc.encode("utf-8"),
            b"-map", b"[o]",
            b"-frames:v", b"1",
        ]
        # fmt: on

        self._ffmpeg_im_o(bap_out, vn, cmd)

    def conv_mp3(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        quality = self.args.q_mp3.lower()
        if self.args.no_acode or not quality:
            raise Exception("disabled in server config")

        self.wait4ram(0.2, tpath)
        tags, rawtags, _, _ = ffprobe(abspath, int(vn.flags["convt"] / 2))
        if "ac" not in tags:
            raise Exception("not audio")

        if quality.endswith("k"):
            qk = b"-b:a"
            qv = quality.encode("ascii")
        else:
            qk = b"-q:a"
            qv = quality[1:].encode("ascii")

        bap_in = fsenc(abspath)
        bap_out = fsenc(tpath)

        # extremely conservative choices for output format
        # (always 2ch 44k1) because if a device is old enough
        # to not support opus then it's probably also super picky

        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner",
            b"-i", bap_in,
        ] + self.big_tags(rawtags) + [
            b"-map", b"0:a:0",
            b"-ar", b"44100",
            b"-ac", b"2",
            b"-c:a", b"libmp3lame",
            qk, qv,
            bap_out,
        ]
        # fmt: on
        self._run_ff(cmd, vn, "aconvt", oom=300)

    def conv_flac(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        if self.args.no_acode or not self.args.allow_flac:
            raise Exception("flac not permitted in server config")

        self.wait4ram(0.2, tpath)
        tags, _, _, _ = ffprobe(abspath, int(vn.flags["convt"] / 2))
        if "ac" not in tags:
            raise Exception("not audio")

        self.log("conv2 flac", 6)

        bap_in = fsenc(abspath)
        bap_out = fsenc(tpath)

        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner",
            b"-i", bap_in,
            b"-map", b"0:a:0",
            b"-c:a", b"flac",
            bap_out,
        ]
        # fmt: on
        self._run_ff(cmd, vn, "aconvt", oom=300)

    def conv_wav(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        if self.args.no_acode or not self.args.allow_wav:
            raise Exception("wav not permitted in server config")

        self.wait4ram(0.2, tpath)
        tags, _, _, _ = ffprobe(abspath, int(vn.flags["convt"] / 2))
        if "ac" not in tags:
            raise Exception("not audio")

        bits = tags[".bps"][1]
        if bits == 0.0:
            bits = tags[".bprs"][1]

        codec = b"pcm_s32le"
        if bits <= 16.0:
            codec = b"pcm_s16le"
        elif bits <= 24.0:
            codec = b"pcm_s24le"

        self.log("conv2 wav", 6)

        bap_in = fsenc(abspath)
        bap_out = fsenc(tpath)

        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner",
            b"-i", bap_in,
            b"-map", b"0:a:0",
            b"-c:a", codec,
            bap_out,
        ]
        # fmt: on
        self._run_ff(cmd, vn, "aconvt", oom=300)

    def conv_opus(self, abspath: str, tpath: str, fmt: str, vn: VFS) -> None:
        if self.args.no_acode or not self.args.q_opus:
            raise Exception("disabled in server config")

        self.wait4ram(0.2, tpath)
        tags, rawtags, _, _ = ffprobe(abspath, int(vn.flags["convt"] / 2))
        if "ac" not in tags:
            raise Exception("not audio")

        sq = "%dk" % (self.args.q_opus,)
        bq = sq.encode("ascii")
        if tags["ac"][1] == "opus":
            enc = "-c:a copy"
        else:
            enc = "-c:a libopus -b:a " + sq

        fun = self._conv_caf if fmt == "caf" else self._conv_owa

        fun(abspath, tpath, tags, rawtags, enc, bq, vn)

    def _conv_owa(
        self,
        abspath: str,
        tpath: str,
        tags: dict[str, tuple[int, Any]],
        rawtags: dict[str, list[Any]],
        enc: str,
        bq: bytes,
        vn: VFS,
    ) -> None:
        if tpath.endswith(".owa"):
            container = b"webm"
            tagset = [b"-map_metadata", b"-1"]
        else:
            container = b"opus"
            tagset = self.big_tags(rawtags)

        self.log("conv2 %s [%s]" % (container, enc), 6)
        benc = enc.encode("ascii").split(b" ")

        ac = b"2"
        try:
            if tags["chs"][1] in ("mono", "1", "1.0"):
                ac = b"1"
        except:
            pass

        bap_in = fsenc(abspath)
        bap_out = fsenc(tpath)

        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner",
            b"-i", bap_in,
        ] + tagset + [
            b"-map", b"0:a:0",
            b"-ac", ac,
        ] + benc + [
            b"-f", container,
            bap_out,
        ]
        # fmt: on
        self._run_ff(cmd, vn, "aconvt", oom=300)

    def _conv_caf(
        self,
        abspath: str,
        tpath: str,
        tags: dict[str, tuple[int, Any]],
        rawtags: dict[str, list[Any]],
        enc: str,
        bq: bytes,
        vn: VFS,
    ) -> None:
        tmp_opus = tpath + ".opus"
        try:
            wunlink(self.log, tmp_opus, vn.flags)
        except:
            pass

        try:
            dur = tags[".dur"][1]
        except:
            dur = 0

        self.log("conv2 caf-tmp [%s]" % (enc,), 6)
        benc = enc.encode("ascii").split(b" ")

        bap_in = fsenc(abspath)
        bap_out = fsenc(tmp_opus)

        # fmt: off
        cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
            b"-nostdin",
            b"-v", b"error",
            b"-hide_banner",
            b"-i", bap_in,
            b"-map_metadata", b"-1",
            b"-map", b"0:a:0",
            b"-ac", b"2",
        ] + benc + [
            b"-f", b"opus",
            bap_out,
        ]
        # fmt: on
        self._run_ff(cmd, vn, "aconvt", oom=300)

        # iOS fails to play some "insufficiently complex" files
        # (average file shorter than 8 seconds), so of course we
        # fix that by mixing in some inaudible pink noise :^)
        # 6.3 sec seems like the cutoff so lets do 7, and
        # 7 sec of psyqui-musou.opus @ 3:50 is 174 KiB
        sz = bos.path.getsize(tmp_opus)
        if dur < 20 or sz < 256 * 1024:
            zs = bq.decode("ascii")
            self.log("conv2 caf-transcode; dur=%d sz=%d q=%s" % (dur, sz, zs), 6)
            bap_in = fsenc(abspath)
            bap_out = fsenc(tpath)
            # fmt: off
            cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
                b"-nostdin",
                b"-v", b"error",
                b"-hide_banner",
                b"-i", bap_in,
                b"-filter_complex", b"anoisesrc=a=0.001:d=7:c=pink,asplit[l][r]; [l][r]amerge[s]; [0:a:0][s]amix",
                b"-map_metadata", b"-1",
                b"-ac", b"2",
                b"-c:a", b"libopus",
                b"-b:a", bq,
                b"-f", b"caf",
                bap_out,
            ]
            # fmt: on
            self._run_ff(cmd, vn, "aconvt", oom=300)

        else:
            # simple remux should be safe
            self.log("conv2 caf-remux; dur=%d sz=%d" % (dur, sz), 6)
            bap_in = fsenc(tmp_opus)
            bap_out = fsenc(tpath)
            # fmt: off
            cmd = bwrap(HAVE_FFMPEG[0], bap_in, bap_out) + [
                b"-nostdin",
                b"-v", b"error",
                b"-hide_banner",
                b"-i", bap_in,
                b"-map_metadata", b"-1",
                b"-map", b"0:a:0",
                b"-c:a", b"copy",
                b"-f", b"caf",
                bap_out,
            ]
            # fmt: on
            self._run_ff(cmd, vn, "aconvt", oom=300)

        try:
            wunlink(self.log, tmp_opus, vn.flags)
        except:
            pass

    def big_tags(self, raw_tags: dict[str, list[str]]) -> list[bytes]:
        ret = []
        for k, vs in raw_tags.items():
            for v in vs:
                if len(unicode(v)) >= 1024:
                    bv = k.encode("utf-8", "replace")
                    ret += [b"-metadata", bv + b"="]
                    break
        return ret

    def poke(self, tdir: str) -> None:
        if not self.poke_cd or not self.poke_cd.poke(tdir):
            return

        ts = int(time.time())
        try:
            for _ in range(4):
                bos.utime(tdir, (ts, ts))
                tdir = os.path.dirname(tdir)
        except:
            pass

    def cleaner(self) -> None:
        interval = self.args.th_clean
        while True:
            ndirs = 0
            for vol, histpath in self.asrv.vfs.histtab.items():
                if histpath.startswith(vol):
                    self.log("\033[Jcln {}/\033[A".format(histpath))
                else:
                    self.log("\033[Jcln {} ({})/\033[A".format(histpath, vol))

                try:
                    ndirs += self.clean(histpath)
                except Exception as ex:
                    self.log("\033[Jcln err in %s: %r" % (histpath, ex), 3)

            self.log("\033[Jcln ok; rm {} dirs".format(ndirs))
            self.rm_nullthumbs = False
            time.sleep(interval)

    def clean(self, histpath: str) -> int:
        cfgi = cfga = ""
        for vn in self.asrv.vfs.all_vols.values():
            if vn.histpath == histpath:
                cfgi = self.volcfgi(vn)
                cfga = self.volcfga(vn)
                break
        for cfg, cat in ((cfgi, "th"), (cfga, "ac")):
            if not cfg:
                continue
            try:
                with open(os.path.join(histpath, cat, "cfg.txt"), "rb") as f:
                    oldcfg = f.read().decode("utf-8")
            except:
                oldcfg = ""
            if cfg == oldcfg:
                continue
            zs = os.path.join(histpath, cat)
            if not os.path.exists(zs):
                continue
            self.log("thumbnailer-config changed; deleting %s" % (zs,), 3)
            shutil.rmtree(zs)

        ret = 0
        for cat in ["th", "ac"]:
            top = os.path.join(histpath, cat)
            if not bos.path.isdir(top):
                continue

            ret += self._clean(cat, top)

        return ret

    def _clean(self, cat: str, thumbpath: str) -> int:
        # self.log("cln {}".format(thumbpath))
        exts = EXTS_TH if cat == "th" else EXTS_AC
        maxage = getattr(self.args, cat + "_maxage")
        now = time.time()
        prev_b64 = None
        prev_fp = ""
        try:
            t1 = statdir(
                self.log_func, not self.args.no_scandir, False, thumbpath, False
            )
            ents = sorted(list(t1))
        except:
            return 0

        ndirs = 0
        for f, inf in ents:
            fp = os.path.join(thumbpath, f)
            cmp = fp.lower().replace("\\", "/")

            # "top" or b64 prefix/full (a folder)
            if len(f) <= 3 or len(f) == 24:
                age = now - inf.st_mtime
                if age > maxage:
                    with self.mutex:
                        safe = True
                        for k in self.busy:
                            if k.lower().replace("\\", "/").startswith(cmp):
                                safe = False
                                break

                        if safe:
                            ndirs += 1
                            self.log("rm -rf [{}]".format(fp))
                            shutil.rmtree(fp, ignore_errors=True)
                else:
                    ndirs += self._clean(cat, fp)

                continue

            # thumb file
            try:
                b64, ts, ext = f.split(".")
                if len(ts) > 8 and PTN_TS.match(ts):
                    ts = "yeahokay"
                if len(b64) != 24 or len(ts) != 8 or ext not in exts:
                    raise Exception()
            except:
                if f != "dir.txt" and f != "cfg.txt":
                    self.log("foreign file in thumbs dir: [{}]".format(fp), 1)

                continue

            if self.rm_nullthumbs and not inf.st_size:
                bos.unlink(fp)
                continue

            if b64 == prev_b64:
                self.log("rm replaced [{}]".format(fp))
                bos.unlink(prev_fp)

            if cat != "th" and inf.st_mtime + maxage < now:
                self.log("rm expired [{}]".format(fp))
                bos.unlink(fp)

            prev_b64 = b64
            prev_fp = fp

        return ndirs
