"""Shared infra: config, disk guard, manifest, failures, remote-zip access."""
import hashlib
import json
import os
import subprocess
import time
import zipfile

import yaml

CFG = yaml.safe_load(open(os.path.join(os.path.dirname(__file__), "..", "config.yaml")))
# BENCH_BASE / BENCH_WORK / BENCH_STORE (2026-09-07): relocate the data roots for off-cluster run packages
BASE = os.environ.get("BENCH_BASE") or CFG["paths"]["base"]
WORK = os.environ.get("BENCH_WORK") or (f"{BASE}/work" if os.environ.get("BENCH_BASE") else CFG["paths"]["work"])
STORE = os.environ.get("BENCH_STORE") or (f"{BASE}/store" if os.environ.get("BENCH_BASE") else CFG["paths"]["store"])
for d in (WORK, STORE, f"{STORE}/annotations", f"{STORE}/samples",
          f"{STORE}/needed_videos", f"{STORE}/normalized", f"{STORE}/audio",
          f"{BASE}/logs"):
    os.makedirs(d, exist_ok=True)

FAILURES = f"{BASE}/logs/failures.jsonl"
MANIFEST = f"{BASE}/logs/manifest.jsonl"
DEDUP_LOG = f"{BASE}/logs/dedup_log.csv"


def log_failure(stage, key, error, **kw):
    rec = dict(ts=time.strftime("%F %T"), stage=stage, key=key, error=str(error)[:500], **kw)
    with open(FAILURES, "a") as f:
        f.write(json.dumps(rec, ensure_ascii=False) + "\n")


def manifest_done():
    done = {}
    if os.path.exists(MANIFEST):
        with open(MANIFEST) as f:
            for line in f:
                try:
                    r = json.loads(line)
                    if r.get("status") == "done":
                        done[r["key"]] = r
                except Exception:
                    pass
    return done


def manifest_write(key, status, **kw):
    with open(MANIFEST, "a") as f:
        f.write(json.dumps(dict(key=key, status=status, ts=time.strftime("%F %T"), **kw),
                           ensure_ascii=False) + "\n")


def du_gb(path):
    r = subprocess.run(["du", "-sb", path], capture_output=True, text=True)
    try:
        return int(r.stdout.split()[0]) / 1e9
    except Exception:
        return 0.0


_DISK_GUARD_CACHE = {"ts": 0.0, "val": None}
DISK_GUARD_TTL_S = 600   # du over the store (~55k files on a network FS) takes seconds; with ~20
                         # concurrent stage_c processes a per-item du dominated wall time (2026-09-03)


def disk_guard(force=False):
    """Return (ok, work_gb, store_gb). Caller MUST stop when not ok.
    Result is cached per process for DISK_GUARD_TTL_S; a not-ok result is never cached."""
    now = time.time()
    c = _DISK_GUARD_CACHE
    if not force and c["val"] is not None and c["val"][0] and now - c["ts"] < DISK_GUARD_TTL_S:
        return c["val"]
    w, s = du_gb(WORK), du_gb(STORE)
    ok = w <= CFG["limits"]["work_dir_limit_gb"] and s <= CFG["limits"]["store_limit_gb"]
    c["ts"], c["val"] = now, (ok, w, s)
    return ok, w, s


def sha256_file(path, bufsize=1 << 20):
    h = hashlib.sha256()
    with open(path, "rb") as f:
        while True:
            b = f.read(bufsize)
            if not b:
                break
            h.update(b)
    return h.hexdigest()


def hf_token():
    p = os.path.expanduser("~/.cache/huggingface/token")
    return open(p).read().strip() if os.path.exists(p) else None


def api_tree(repo, revision=None):
    """Full recursive file listing with sizes. Uses huggingface_hub pagination —
    the raw /tree REST endpoint silently truncates at 1000 entries.
    revision=None keeps the historical behavior (default branch / main);
    pass a commit sha or tag to pin (see exp/watch/REVISION_PINNING.md)."""
    from huggingface_hub import HfApi
    out = []
    for it in HfApi(token=hf_token()).list_repo_tree(repo, repo_type="dataset",
                                                     recursive=True, expand=False,
                                                     revision=revision):
        if getattr(it, "size", None) is not None:  # RepoFile
            out.append(dict(type="file", path=it.path, size=it.size))
    return out


_fs = None

def hffs():
    global _fs
    if _fs is None:
        from huggingface_hub import HfFileSystem
        _fs = HfFileSystem(token=hf_token())
    return _fs


_zip_handles = {}

def remote_zip(repo, zip_path):
    """Open a zip inside an HF dataset repo with range reads. Cached per path."""
    key = f"datasets/{repo}/{zip_path}"
    if key not in _zip_handles:
        f = hffs().open(key, "rb")
        _zip_handles[key] = zipfile.ZipFile(f)
    return _zip_handles[key]


def zip_namelist(repo, zip_path):
    return remote_zip(repo, zip_path).namelist()


def extract_member(repo, zip_path, member, dest):
    """Stream ONE member out of a remote zip (only its bytes transferred)."""
    zf = remote_zip(repo, zip_path)
    with zf.open(member) as src, open(dest, "wb") as out:
        while True:
            b = src.read(1 << 20)
            if not b:
                break
            out.write(b)
    return dest


TAR_EXT = (".tar", ".tar.gz", ".tgz", ".tar.bz2")
TAR_COMPRESSED = (".tar.gz", ".tgz", ".tar.bz2")
TAR_STREAM_CAP_GB = 10  # compressed tars have no random access; cap full-stream size

_tar_handles = {}


class ConcatFile:
    """Read-only seekable concatenation of fsspec files (split .tar.part.* archives)."""

    def __init__(self, fs, paths, sizes=None):
        self.fs = fs
        self.parts = []
        off = 0
        for i, p in enumerate(paths):
            size = sizes[i] if sizes and sizes[i] is not None else fs.info(p)["size"]
            self.parts.append((off, size, p))
            off += size
        self.size = off
        self.pos = 0
        self._open = {}

    # tarfile callers use `with _open_remote(...) as f` — without these the
    # first chunked-archive access dies with AttributeError: __enter__
    def __enter__(self):
        return self

    def __exit__(self, *exc):
        self.close()
        return False

    def seek(self, pos, whence=0):
        if whence == 1:
            pos += self.pos
        elif whence == 2:
            pos += self.size
        self.pos = max(0, pos)
        return self.pos

    def tell(self):
        return self.pos

    def read(self, n=-1):
        if n is None or n < 0:
            n = self.size - self.pos
        out = []
        while n > 0 and self.pos < self.size:
            hit = next(((o, s, p) for o, s, p in self.parts if o <= self.pos < o + s), None)
            if hit is None:
                break
            off, size, p = hit
            f = self._open.get(p)
            if f is None:
                f = self._open[p] = self.fs.open(p, "rb")
            f.seek(self.pos - off)
            chunk = f.read(min(n, off + size - self.pos))
            if not chunk:
                break
            out.append(chunk)
            self.pos += len(chunk)
            n -= len(chunk)
        return b"".join(out)

    def seekable(self):
        return True

    def readable(self):
        return True

    def close(self):
        for f in self._open.values():
            f.close()


_glob_cache = {}


def _natsort_key(p):
    """Natural sort: 'x.part2' < 'x.part10' (lexicographic puts part10 between
    part1 and part2 and CORRUPTS concatenated split archives)."""
    import re
    return [int(t) if t.isdigit() else t for t in re.split(r"(\d+)", str(p))]


def _open_remote(key):
    """fsspec handle for a repo path; a '*' means split chunks joined in order.
    glob+sizes are cached per pattern: without this every per-key fallback
    redoes 1 glob + N info() calls against the HF paths-info API and the
    1000 req/5min quota dies (VideoEval-Pro: 194 keys x 36 calls -> 429)."""
    fs = hffs()
    if "*" in key:
        cached = _glob_cache.get(key)
        if cached is None:
            detail = fs.glob(key, detail=True)
            if not detail:
                raise FileNotFoundError(key)
            cached = sorted(((p, (info or {}).get("size"))
                             for p, info in detail.items()),
                            key=lambda x: _natsort_key(x[0]))
            _glob_cache[key] = cached
        return ConcatFile(fs, [p for p, _ in cached], [s for _, s in cached])
    return fs.open(key, "rb")


def remote_tar(repo, tar_path):
    """Seekable tarfile for plain .tar (range reads). None for compressed.
    If tar_path itself doesn't exist, looks for split parts <tar_path>.part*."""
    import tarfile
    key = f"datasets/{repo}/{tar_path}"
    if key not in _tar_handles:
        if tar_path.lower().endswith(TAR_COMPRESSED) or "*" in tar_path:
            _tar_handles[key] = None
        else:
            fs = hffs()
            if fs.exists(key):
                f = fs.open(key, "rb")
            else:
                parts = sorted(fs.glob(key + ".part*"), key=_natsort_key)
                if not parts:
                    raise FileNotFoundError(key)
                f = ConcatFile(fs, parts)
            _tar_handles[key] = tarfile.open(fileobj=f, mode="r:")
    return _tar_handles[key]


def tar_namelist(repo, tar_path):
    """Member listing with a disk cache — remote tar walks cost ~0.1s/member."""
    import tarfile
    cache_dir = f"{STORE}/tar_index"
    os.makedirs(cache_dir, exist_ok=True)
    cache = f"{cache_dir}/{repo.replace('/', '__')}__{tar_path.replace('/', '__')}.json"
    if os.path.exists(cache):
        return json.load(open(cache))
    tf = remote_tar(repo, tar_path)
    if tf is not None:
        names = [m.name for m in tf.getmembers() if m.isfile()]
    else:
        names = []
        with _open_remote(f"datasets/{repo}/{tar_path}") as f, \
                tarfile.open(fileobj=f, mode="r|*") as t:
            for m in t:
                if m.isfile():
                    names.append(m.name)
    tmp = f"{cache}.tmp{os.getpid()}"    # atomic: concurrent shards write it
    json.dump(names, open(tmp, "w"))
    os.replace(tmp, cache)
    return names


def extract_tar_member(repo, tar_path, member, dest):
    import shutil
    import tarfile
    tf = remote_tar(repo, tar_path)
    if tf is not None:
        src = tf.extractfile(member)
        with open(dest, "wb") as out:
            shutil.copyfileobj(src, out, 1 << 20)
        return dest
    with _open_remote(f"datasets/{repo}/{tar_path}") as f, \
            tarfile.open(fileobj=f, mode="r|*") as t:
        for m in t:
            if m.name == member:
                with open(dest, "wb") as out:
                    shutil.copyfileobj(t.extractfile(m), out, 1 << 20)
                return dest
    raise KeyError(f"{member} not in {tar_path}")


def extract_tar_members_bulk(repo, tar_path, members, dest_dir):
    """One streaming pass through a (compressed) tar, extracting every wanted
    member — avoids re-streaming the whole archive per video."""
    import shutil
    import tarfile
    os.makedirs(dest_dir, exist_ok=True)
    want = set(members)
    got = {}
    with _open_remote(f"datasets/{repo}/{tar_path}") as f, \
            tarfile.open(fileobj=f, mode="r|*") as t:
        for m in t:
            if m.name in want:
                dest = os.path.join(dest_dir, m.name.replace("/", "_"))
                with open(dest, "wb") as out:
                    shutil.copyfileobj(t.extractfile(m), out, 1 << 20)
                got[m.name] = dest
                if len(got) == len(want):
                    break
    return got


def hf_download_file(repo, path, dest_dir, revision=None):
    """revision=None keeps the historical behavior (default branch / main);
    pass a commit sha to pin (see exp/watch/REVISION_PINNING.md)."""
    from huggingface_hub import hf_hub_download
    return hf_hub_download(repo_id=repo, filename=path, repo_type="dataset",
                           local_dir=dest_dir, token=hf_token(), revision=revision)


def ffprobe(path):
    r = subprocess.run(["ffprobe", "-v", "error", "-print_format", "json",
                        "-show_format", "-show_streams", path],
                       capture_output=True, text=True, timeout=300)
    return json.loads(r.stdout)