#!/usr/bin/env python3
"""CTF challenge tracker.

Lists every repo in the GitLab challenges group, reads each repo's README.md
(the filled-out challenge template) and reports:
  * a terminal summary: status per category, category x difficulty, open issues
  * a HedgeDoc-ready markdown overview

Config: see ctf_status.env.example -> ctf_status.env (chmod 600)
"""
from __future__ import annotations

import argparse
import base64
import fcntl
import json
import os
import random
import re
import sys
import tempfile
import time
from collections import Counter, defaultdict
from concurrent.futures import ThreadPoolExecutor
from dataclasses import dataclass, field
from datetime import datetime
from pathlib import Path
from urllib.parse import quote, urlsplit

import requests

# ---------------------------------------------------------------- config ----

CFG_KEYS = ("GITLAB_GROUP_URL", "GITLAB_TOKEN")
OPT_KEYS = ("HEDGEDOC_NOTE", "HEDGEDOC_TAGS", "TITLE",
            "CHALLS_REPO_URL", "CHALLS_PATH", "CHALLS_BRANCH")
# the names a plain `.env` tends to use for the same thing
ALIASES = {"GL_PAT": "GITLAB_TOKEN", "GITLAB_URL": "GITLAB_GROUP_URL"}
DEFAULT_TAGS = "Logistics, h4tum CTF 2026"
DEFAULT_TITLE = "CTF challenge tracking"
DEFAULT_CHALLS_PATH = "2026/challs.txt"


def load_env() -> dict:
    cfg = {}
    here = Path(__file__).parent
    # every file that exists contributes; the first one to set a key wins
    for candidate in (here / "ctf_status.env", here / ".env",
                      Path.home() / ".config" / "ctf-status" / "env"):
        if not candidate.exists():
            continue
        for line in candidate.read_text().splitlines():
            line = line.strip()
            if not line or line.startswith("#") or "=" not in line:
                continue
            k, v = line.split("=", 1)
            k = k.strip().upper()
            cfg.setdefault(ALIASES.get(k, k), v.strip().strip("'\""))
    for k in CFG_KEYS + OPT_KEYS + tuple(ALIASES):
        if os.environ.get(k):
            cfg[ALIASES.get(k, k)] = os.environ[k]
    missing = [k for k in CFG_KEYS if not cfg.get(k)]
    if missing:
        sys.exit(f"missing config: {', '.join(missing)} (see ctf_status.env.example)")
    return cfg


# --------------------------------------------------------------- gitlab -----

@dataclass
class Repo:
    path: str
    web_url: str
    ssh_url: str
    last_activity: str  # YYYY-MM-DD
    readme: str | None  # None: the repo has no README at all


class GitLab:
    """Access to one group, plus the one file we write elsewhere. The token needs
    Project: Read (to list the group) and Repository: Read (to download files);
    --challs additionally needs read + write on the deployment repo."""

    def __init__(self, group_url: str, token: str, timeout: int = 20):
        parts = urlsplit(group_url)
        self.api = f"{parts.scheme}://{parts.netloc}/api/v4"
        self.group = parts.path.strip("/")
        self.timeout = timeout
        self.s = requests.Session()
        self.s.headers["PRIVATE-TOKEN"] = token

    def _get(self, url: str, **params) -> requests.Response:
        return self._req("GET", url, params=params)

    def _req(self, method: str, url: str, ok: tuple = (), **kw) -> requests.Response:
        r = self.s.request(method, url, timeout=self.timeout, **kw)
        if r.status_code in ok:
            return r
        if r.status_code == 403:
            # fine-grained tokens say exactly which permission is missing
            try:
                why = r.json().get("error_description") or r.text
            except ValueError:
                why = r.text
            raise RuntimeError(f"gitlab refused {r.url}: {why}")
        r.raise_for_status()
        return r

    def projects(self) -> list[dict]:
        out, page = [], "1"
        while page:
            r = self._get(f"{self.api}/groups/{quote(self.group, safe='')}/projects",
                          include_subgroups="true", per_page="100", page=page,
                          order_by="path", sort="asc")
            out += r.json()
            page = r.headers.get("X-Next-Page", "")
        # repos GitLab is about to delete are renamed "...-deletion_scheduled-<id>"
        return [p for p in out if not p.get("archived") and not p.get("marked_for_deletion_on")]

    def readme(self, p: dict) -> str | None:
        branch, url = p.get("default_branch"), p.get("readme_url")
        if not branch or not url or f"/-/blob/{branch}/" not in url:
            return None
        path = url.split(f"/-/blob/{branch}/", 1)[1]
        r = self._get(f"{self.api}/projects/{p['id']}/repository/files/"
                      f"{quote(path, safe='')}/raw", ref=branch)
        return r.content.decode("utf-8", "replace")

    def repos(self) -> list[Repo]:
        projects = self.projects()

        def fetch(p: dict) -> Repo:
            return Repo(path=p["path"], web_url=p["web_url"],
                        ssh_url=p["ssh_url_to_repo"],
                        last_activity=(p.get("last_activity_at") or "")[:10],
                        readme=self.readme(p))

        with ThreadPoolExecutor(max_workers=8) as pool:
            return list(pool.map(fetch, projects))

    def write_file(self, repo_url: str, path: str, content: str, branch: str | None,
                   message) -> bool:
        """Commit `content` to `path` in the repo at `repo_url` (a web URL), creating
        the file if needed; `message(old_content)` makes the commit message.
        False if the file already said exactly this."""
        proj = quote(urlsplit(repo_url).path.strip("/").split("/-/", 1)[0], safe="")
        base = f"{self.api}/projects/{proj}"
        if not branch:
            branch = self._get(base).json()["default_branch"]
        url = f"{base}/repository/files/{quote(path, safe='')}"
        r = self._req("GET", url, ok=(404,), params={"ref": branch})
        exists = r.status_code != 404
        old = base64.b64decode(r.json()["content"]).decode("utf-8", "replace") if exists else ""
        if exists and old == content:
            return False
        self._req("PUT" if exists else "POST", url,
                  json={"branch": branch, "content": content, "commit_message": message(old)})
        return True


# --------------------------------------------------------------- parsing ----

FIELDS = ("Category", "Difficulty", "Event", "Author", "Tester", "Status")
HEADING_RE = re.compile(r"^\s{0,3}#{1,4}\s+(.+?)\s*$", re.M)
FIELD_RE = re.compile(r"^\s*[-*]\s*\**(?P<key>[A-Za-z ]+?)\**\s*:\s*(?P<val>.*?)\s*$", re.M)
# a value the author never touched: "[crypto, pwn, ...]" or "[Author Name]"
PLACEHOLDER_RE = re.compile(r"^\[.*\]$")
NO_TESTER_RE = re.compile(r"^(\?+|none|tester name|not found\b.*|tbd)(\s.*)?$", re.I)

STATUS_ORDER = ["Planning", "PoC Draft", "Testing Ready", "Tested", "Ready"]
STATUS_RE = re.compile(r"testing\s*ready|tested|ready|poc(?:\s*draft)?|planning", re.I)
STATUS_ICON = {"Planning": "⚪", "PoC Draft": "🟠", "Testing Ready": "🟡",
               "Tested": "🔵", "Ready": "🟢", None: "❔"}
CATEGORIES = ["crypto", "pwn", "web", "rev", "misc", "osint", "forensic", "hardware"]
DIFFICULTIES = ["intro", "easy", "medium", "hard"]
DIFF_RE = re.compile(r"intro|easy|medium|hard", re.I)
DIFF_RANGE_RE = re.compile(r"(intro|easy|medium|hard)\s*(?:-|–|/|\bto\b)\s*(intro|easy|medium|hard)", re.I)


def clean(v: str) -> str:
    v = re.sub(r"\\+([\[\]_*])", r"\1", v)  # markdown escapes, sometimes doubled
    return v.replace("**", "").strip()


def is_placeholder(v: str) -> bool:
    v = clean(v)
    return not v or bool(PLACEHOLDER_RE.match(v))


def stage_of(raw: str) -> tuple[str | None, bool]:
    """Map a free-text status onto STATUS_ORDER -> (stage, clear).

    "Tested with h4tum-chall-format" is clearly Tested. "Planning to PoC Draft"
    or a half-deleted option list is not; we take the least advanced stage it
    names, so nothing looks further along than it is, and call it unclear."""
    if is_placeholder(raw):
        return None, False
    found = set()
    for m in STATUS_RE.finditer(raw):
        w = m.group(0).lower()
        found.add("Testing Ready" if w.startswith("testing") else
                  "PoC Draft" if w.startswith("poc") else w.title())
    if not found:
        return None, False
    return min(found, key=STATUS_ORDER.index), len(found) == 1


def difficulty_of(raw: str) -> str | None:
    """"medium/hard", "medium-hard", "easy to medium" -> a range "medium-hard"."""
    if is_placeholder(raw):
        return None
    m = DIFF_RANGE_RE.search(raw)
    if m:
        ends = sorted({m.group(1).lower(), m.group(2).lower()}, key=DIFFICULTIES.index)
        return "-".join(ends) if len(ends) > 1 else ends[0]
    # prose like "currently medium, maybe also an easy and a hard version": the first one
    m = DIFF_RE.search(raw)
    return m.group(0).lower() if m else None


def difficulty_rank(d: str | None) -> float:
    if not d:
        return 99
    ends = d.split("-")
    return sum(DIFFICULTIES.index(e) for e in ends) / len(ends)


@dataclass
class Challenge:
    repo: Repo
    name: str = ""
    fields: dict = field(default_factory=dict)

    def get(self, key: str, dash: str = "—") -> str:
        v = clean(self.fields.get(key, ""))
        return dash if is_placeholder(v) else v

    # -- derived -----------------------------------------------------------
    @property
    def named(self) -> bool:
        return bool(self.name) and not is_placeholder(self.name)

    @property
    def title(self) -> str:
        return self.name if self.named else self.repo.path

    @property
    def touched(self) -> bool:
        """Did anyone put *any* real content in the README template?"""
        return self.named or any(not is_placeholder(self.fields.get(f, "")) for f in FIELDS)

    @property
    def status_raw(self) -> str:
        return self.get("Status")

    @property
    def stage(self) -> str | None:
        return stage_of(self.fields.get("Status", ""))[0]

    @property
    def difficulty(self) -> str | None:
        return difficulty_of(self.fields.get("Difficulty", ""))

    @property
    def category(self) -> str | None:
        """The first category named; "rev, misc" counts as rev."""
        raw = self.get("Category", "")
        first = re.split(r"[,/&+]| and ", raw)[0].strip().lower()
        return first or None

    @property
    def has_tester(self) -> bool:
        t = self.get("Tester", "")
        return bool(t) and not NO_TESTER_RE.match(t)

    @property
    def problems(self) -> list[str]:
        p = []
        stage, clear = stage_of(self.fields.get("Status", ""))
        if stage is None:
            p.append(f"status unknown ({self.status_raw!r})" if self.status_raw != "—"
                     else "no status")
        elif not clear:
            p.append(f"status unclear ({self.status_raw!r}, counted as {stage})")
        if not self.category:
            p.append("no category")
        if not self.difficulty:
            p.append(f"difficulty unclear ({self.get('Difficulty')!r})"
                     if self.get("Difficulty") != "—" else "no difficulty")
        if is_testable(self) and not self.has_tester:
            p.append("no tester")
        if not self.named:
            p.append("no challenge name in README")
        return p


def is_testable(c: Challenge) -> bool:
    return bool(c.stage) and STATUS_ORDER.index(c.stage) >= STATUS_ORDER.index("Testing Ready")


def parse_challenge(repo: Repo) -> Challenge:
    c = Challenge(repo=repo)
    text = repo.readme or ""
    m = HEADING_RE.search(text)
    if m:
        c.name = clean(m.group(1))
    for fm in FIELD_RE.finditer(text):
        key = fm.group("key").strip().title()
        if key in FIELDS and key not in c.fields:
            c.fields[key] = fm.group("val")
    return c


# ---------------------------------------------------------------- report ----

BOLD, DIM, RED, YEL, GRN, CYA, RST = (
    "\033[1m", "\033[2m", "\033[31m", "\033[33m", "\033[32m", "\033[36m", "\033[0m")


@dataclass
class Overview:
    challenges: list  # repos with a README somebody filled in
    blank: list       # repos with no README, or an untouched template

    @property
    def categories(self) -> list[str]:
        extra = sorted({c.category or "?" for c in self.challenges} - set(CATEGORIES))
        return CATEGORIES + extra

    @property
    def difficulties(self) -> list[str]:
        seen = {c.difficulty for c in self.challenges if c.difficulty}
        unknown = ["?"] if any(not c.difficulty for c in self.challenges) else []
        return sorted(set(DIFFICULTIES) | seen, key=difficulty_rank) + unknown

    @property
    def stages(self) -> list:
        """The five stages, plus None ("?") only if some status is unreadable."""
        return STATUS_ORDER + ([None] if any(not c.stage for c in self.challenges) else [])

    @property
    def testable(self) -> list:
        """Everything infra can already deploy and test: Testing Ready or beyond."""
        return sorted((c for c in self.challenges if is_testable(c)),
                      key=lambda c: (self.categories.index(c.category or "?"),
                                     difficulty_rank(c.difficulty), c.title.lower()))

    def by_category(self) -> dict[str, list]:
        out = defaultdict(list)
        for c in self.challenges:
            out[c.category or "?"].append(c)
        for chs in out.values():
            chs.sort(key=lambda c: (-STATUS_ORDER.index(c.stage) if c.stage else 1,
                                    difficulty_rank(c.difficulty), c.title.lower()))
        return out


def collect(gl: GitLab) -> Overview:
    chs, blank = [], []
    for repo in gl.repos():
        c = parse_challenge(repo)
        (chs if c.touched else blank).append(c)
    return Overview(chs, sorted(blank, key=lambda c: c.repo.path.lower()))


def icons(chs: list) -> str:
    return "".join(STATUS_ICON[c.stage] for c in chs)


def print_terminal(ov: Overview, c: bool) -> None:
    def col(x): return x if c else ""
    stages = ov.stages
    groups = ov.by_category()

    total = Counter(ch.stage for ch in ov.challenges)
    print(f"\n{col(BOLD)}=== {len(ov.challenges)} challenges ==={col(RST)}  "
          + "  ".join(f"{STATUS_ICON[s]} {s or '?'}:{total[s]}" for s in stages if total[s]))

    ready = ov.testable
    print(f"\n{col(BOLD)}{col(GRN)}=== ready for infra testing ({len(ready)}) ==={col(RST)}")
    for ch in ready:
        print(f"  {STATUS_ICON[ch.stage]} {ch.title[:34]:<35}{ch.category or '?':<10}"
              f"{ch.difficulty or '?':<13}{col(DIM)}{ch.repo.web_url}{col(RST)}")

    print(f"\n{col(BOLD)}=== status by category ==={col(RST)}")
    print(f"  {'':<10}" + "".join(f"{s or '?':>14}" for s in stages) + f"{'total':>7}")
    for cat in ov.categories:
        chs = groups.get(cat, [])
        cnt = Counter(ch.stage for ch in chs)
        tint = "" if chs else DIM
        print(f"  {col(tint)}{cat:<10}" + "".join(f"{cnt[s] or '·':>14}" for s in stages)
              + f"{len(chs):>7}{col(RST)}")

    print(f"\n{col(BOLD)}=== category × difficulty ==={col(RST)}  "
          + "  ".join(f"{STATUS_ICON[s]} {s}" for s in STATUS_ORDER))
    diffs = ov.difficulties
    print(f"  {'':<10}" + "".join(f"{d:<13}" for d in diffs))
    for cat in ov.categories:
        chs = groups.get(cat, [])
        cells = [icons([ch for ch in chs if (ch.difficulty or "?") == d]) for d in diffs]
        # emoji are two columns wide in a terminal
        print(f"  {cat:<10}" + "".join(f"{x or '·'}{' ' * (13 - (2 * len(x) if x else 1))}"
                                       for x in cells))

    print(f"\n{col(BOLD)}=== needs attention ==={col(RST)}")
    for ch in sorted(ov.challenges, key=lambda c: c.repo.path.lower()):
        if ch.problems:
            print(f"  {col(YEL)}{ch.repo.path:<32}{col(RST)} {col(DIM)}"
                  + "; ".join(ch.problems) + col(RST))
    for ch in ov.blank:
        why = "no README" if ch.repo.readme is None else "README is still the blank template"
        print(f"  {col(RED)}{ch.repo.path:<32}{col(RST)} {col(DIM)}{why}{col(RST)}")
    print()


def render_challs(ov: Overview) -> str:
    """The deployment repo's challs.txt: one clone URL per line, for everything
    that is Testing Ready or beyond."""
    return "".join(f"{c.repo.ssh_url}\n" for c in ov.testable)


def challs_message(old: str, new: str, path: str) -> str:
    name = lambda u: u.rsplit("/", 1)[-1].removesuffix(".git")
    was, now = set(old.split()), set(new.split())
    parts = [f"+{name(u)}" for u in sorted(now - was)] + [f"-{name(u)}" for u in sorted(was - now)]
    return f"Update {path} from challenge status" + (f": {' '.join(parts)}" if parts else "")


def md_cell(v: str) -> str:
    return v.replace("|", "\\|")


def render_hedgedoc(ov: Overview, title: str, tags: str = "") -> str:
    stamp = datetime.now().astimezone().strftime("%Y-%m-%d %H:%M:%S %Z")
    stages = ov.stages
    groups = ov.by_category()
    total = Counter(ch.stage for ch in ov.challenges)
    L = []
    if tags:
        # HedgeDoc reads this YAML block off the top of the note
        L += ["---", f"tags: {tags}", "---", ""]
    L += [f"# {title}", "",
          f"**Last updated:** {stamp}", "",
          f"*generated by `ctf_status.py` from the README.md of every repo in the "
          f"GitLab challenges group — {len(ov.challenges)} challenges*", "",
          " · ".join(f"{STATUS_ICON[s]} **{s or 'unknown'}** {total[s]}"
                     for s in stages if total[s] or s), ""]

    ready = ov.testable
    L += [f"## ✅ Ready for infra testing ({len(ready)} of {len(ov.challenges)})", "",
          "*every challenge at Testing Ready or beyond — these can be deployed and "
          "tested against the infrastructure now*", ""]
    if ready:
        L += ["| | Challenge | Category | Difficulty | Status | Event | Author | Tester |",
              "| --- | --- | --- | --- | --- | --- | --- | --- |"]
        for ch in ready:
            L.append("| " + " | ".join(md_cell(x) for x in (
                STATUS_ICON[ch.stage], f"[{ch.title}]({ch.repo.web_url})",
                ch.category or "?", ch.difficulty or "?", ch.stage, ch.get("Event"),
                ch.get("Author"), ch.get("Tester") if ch.has_tester else "—")) + " |")
    else:
        L.append("*nothing yet*")
    L.append("")

    L += ["## Status by category", "",
          "| Category | " + " | ".join(f"{STATUS_ICON[s]} {s or '?'}" for s in stages)
          + " | total |",
          "| --- |" + " ---: |" * (len(stages) + 1)]
    for cat in ov.categories:
        chs = groups.get(cat, [])
        cnt = Counter(ch.stage for ch in chs)
        L.append(f"| {cat} | " + " | ".join(str(cnt[s] or "·") for s in stages)
                 + f" | **{len(chs)}** |")
    L.append("| **total** | " + " | ".join(f"**{total[s]}**" for s in stages)
             + f" | **{len(ov.challenges)}** |")

    diffs = ov.difficulties
    L += ["", "## Category × difficulty", "",
          "*one dot per challenge, coloured by status: "
          + " ".join(f"{STATUS_ICON[s]} {s}" for s in STATUS_ORDER) + "*", "",
          "| Category | " + " | ".join(diffs) + " | total |",
          "| --- |" + " --- |" * len(diffs) + " ---: |"]
    for cat in ov.categories:
        chs = groups.get(cat, [])
        cells = [icons([ch for ch in chs if (ch.difficulty or "?") == d]) or "·" for d in diffs]
        L.append(f"| {cat} | " + " | ".join(cells) + f" | **{len(chs)}** |")
    dtot = Counter(ch.difficulty or "?" for ch in ov.challenges)
    L.append("| **total** | " + " | ".join(f"**{dtot[d]}**" for d in diffs)
             + f" | **{len(ov.challenges)}** |")

    L += ["", "## Challenges"]
    for cat in ov.categories:
        chs = groups.get(cat)
        if not chs:
            continue
        L += ["", f"### {cat} ({len(chs)})", "",
              "| | Challenge | Difficulty | Status | Event | Author | Tester | Last activity |",
              "| --- | --- | --- | --- | --- | --- | --- | --- |"]
        for ch in chs:
            status = ch.stage or "?"
            if ch.status_raw.lower() != status.lower():
                status += f" *({ch.status_raw})*"
            cat_raw = ch.get("Category", "")
            name = f"[{md_cell(ch.title)}]({ch.repo.web_url})"
            if cat_raw.lower() != cat:
                name += f" *({cat_raw})*"
            L.append("| " + " | ".join(md_cell(x) for x in (
                STATUS_ICON[ch.stage], name, ch.difficulty or ch.get("Difficulty"), status,
                ch.get("Event"), ch.get("Author"),
                ch.get("Tester") if ch.has_tester else "—", ch.repo.last_activity)) + " |")

    L += ["", "## Needs attention", ""]
    issues = [ch for ch in sorted(ov.challenges, key=lambda c: c.repo.path.lower()) if ch.problems]
    for ch in issues:
        L.append(f"- [{md_cell(ch.title)}]({ch.repo.web_url}): " + "; ".join(ch.problems))
    for ch in ov.blank:
        why = "no README" if ch.repo.readme is None else "README is still the blank template"
        L.append(f"- [{ch.repo.path}]({ch.repo.web_url}): {why}")
    if not issues and not ov.blank:
        L.append("*nothing — every README is filled in. suspicious.*")
    return "\n".join(L) + "\n"


# ------------------------------------------------------ hedgedoc (write) ----

# engine.io v3 packet types
EIO_OPEN, EIO_CLOSE, EIO_PING, EIO_PONG, EIO_MSG = "0", "1", "2", "3", "4"
# socket.io packet types, as the second character of an EIO_MSG packet
SIO_CONNECT, SIO_DISCONNECT, SIO_EVENT, SIO_ERROR = "0", "1", "2", "4"


def u16len(s: str) -> int:
    """Length in UTF-16 code units — what JavaScript's `String.length` counts, and
    therefore what engine.io payload framing and OT operations count. Matters as
    soon as the markdown holds an emoji (🔴 is one Python char but two units)."""
    return len(s.encode("utf-16-le")) // 2


def encode_payload(packets: tuple) -> bytes:
    return "".join(f"{u16len(p)}:{p}" for p in packets).encode("utf-8")


def decode_payload(text: str) -> list[str]:
    buf = text.encode("utf-16-le")
    out, i = [], 0
    while i < len(buf):
        j = i
        while buf[j:j + 2] != b":\x00":
            j += 2
            if j >= len(buf):
                raise RuntimeError("malformed engine.io payload")
        n = int(buf[i:j].decode("utf-16-le"))
        j += 2
        out.append(buf[j:j + 2 * n].decode("utf-16-le"))
        i = j + 2 * n
    return out


class HedgeDocNote:
    """Overwrite an existing HedgeDoc 1.x note in place.

    HedgeDoc 1.x has no REST endpoint that edits a note's body, so this speaks the
    same engine.io/socket.io protocol the web editor uses, over XHR long-polling
    (no extra dependencies beyond `requests`):

        GET /<note>          -> session cookie; the socket rejects us without one
        GET /socket.io/      -> engine.io handshake, yields a session id
        poll for 'doc'       -> the note's current text and OT revision
        emit 'operation'     -> [-len(old), new]: delete everything, insert ours
        poll for 'ack'       -> the server applied it and told the other editors

    The note's permission must allow us to write ("freely" for an anonymous run).
    """

    def __init__(self, url: str, timeout: int = 20):
        parts = urlsplit(url)
        path = parts.path.rstrip("/")
        if not parts.scheme or not parts.netloc or "/" not in path:
            raise ValueError(f"expected a note URL like https://host/<noteId>, got {url!r}")
        self.note = path.rsplit("/", 1)[-1]
        prefix = path[: -len(self.note)].rstrip("/")
        self.base = f"{parts.scheme}://{parts.netloc}{prefix}"
        self.timeout = timeout
        self.sid: str | None = None
        self.s = requests.Session()
        self.s.headers["Origin"] = f"{parts.scheme}://{parts.netloc}"

    # -- transport ---------------------------------------------------------
    def _params(self) -> dict:
        p = {"EIO": "3", "transport": "polling", "noteId": self.note,
             "t": format(random.getrandbits(40), "x")}
        if self.sid:
            p["sid"] = self.sid
        return p

    def _open(self) -> None:
        self.sid = None
        self.s.get(f"{self.base}/{self.note}", timeout=self.timeout).raise_for_status()
        r = self.s.get(f"{self.base}/socket.io/", params=self._params(), timeout=self.timeout)
        r.raise_for_status()
        pkts = decode_payload(r.text)
        if not pkts or pkts[0][:1] != EIO_OPEN:
            raise RuntimeError(f"unexpected engine.io handshake: {pkts[:1]}")
        self.sid = json.loads(pkts[0][1:])["sid"]

    def _send(self, *packets: str) -> None:
        r = self.s.post(f"{self.base}/socket.io/", params=self._params(),
                        data=encode_payload(packets),
                        headers={"Content-Type": "text/plain;charset=UTF-8"},
                        timeout=self.timeout)
        r.raise_for_status()

    def _events(self):
        """Poll once, answer keepalives, yield decoded socket.io events."""
        r = self.s.get(f"{self.base}/socket.io/", params=self._params(), timeout=self.timeout)
        r.raise_for_status()
        for p in decode_payload(r.text):
            if p == EIO_PING:
                self._send(EIO_PONG)
            elif p == EIO_CLOSE:
                raise RuntimeError("hedgedoc closed the connection")
            elif p[:1] == EIO_MSG:
                kind, data = p[1:2], p[2:]
                if kind == SIO_ERROR:
                    raise RuntimeError(f"hedgedoc refused the socket: {data}")
                if kind == SIO_EVENT:
                    yield json.loads(data)

    def _wait(self, name: str, polls: int = 8):
        for _ in range(polls):
            for ev in self._events():
                if ev and ev[0] == name:
                    return ev[1] if len(ev) > 1 else None
        raise RuntimeError(f"timed out waiting for {name!r} from hedgedoc")

    def _close(self) -> None:
        try:
            self._send(EIO_MSG + SIO_DISCONNECT, EIO_CLOSE)
        except requests.RequestException:
            pass  # we already got our ack; a tidy goodbye is a nicety

    # -- api ---------------------------------------------------------------
    def download(self) -> str:
        r = self.s.get(f"{self.base}/{self.note}/download", timeout=self.timeout)
        r.raise_for_status()
        return r.content.decode("utf-8", "replace")

    def replace(self, markdown: str) -> bool:
        """Replace the note body. False if it already said exactly this."""
        self._open()
        doc = self._wait("doc")
        old, revision = doc["str"], doc["revision"]
        if old == markdown:
            self._close()
            return False
        # an OT operation is a list of: n>0 keep n chars, n<0 drop n, str insert
        ops = ([-u16len(old)] if old else []) + ([markdown] if markdown else [])
        self._send(EIO_MSG + SIO_EVENT
                   + json.dumps(["operation", revision, ops, None], ensure_ascii=False))
        self._wait("ack")
        time.sleep(2)  # give the realtime server a moment to flush the note to its DB
        self._close()
        return True


def update_hedgedoc(url: str, md: str, retries: int = 3, quiet: bool = False) -> bool:
    """Write `md` into the existing note at `url`, then read it back to be sure."""
    for attempt in range(1, retries + 1):
        try:
            note = HedgeDocNote(url)
            changed = note.replace(md)
            if note.download() != md:
                raise RuntimeError("note does not match what we wrote")
            return changed
        except (requests.RequestException, RuntimeError, ValueError, KeyError) as e:
            if attempt == retries:
                raise
            if not quiet:
                print(f"hedgedoc update failed ({e}) — retry {attempt + 1}/{retries}",
                      file=sys.stderr)
            time.sleep(3 * attempt)
    return False


def push_hedgedoc(base: str, md: str) -> str:
    r = requests.post(base.rstrip("/") + "/new", data=md.encode(),
                      headers={"Content-Type": "text/markdown"}, allow_redirects=False)
    r.raise_for_status()
    loc = r.headers.get("Location", "")
    return loc if loc.startswith("http") else base.rstrip("/") + loc


def single_run_lock():
    """Keep a slow or hung cron run from colliding with the next one."""
    fh = open(Path(tempfile.gettempdir()) / "ctf_status.lock", "w")
    try:
        fcntl.flock(fh, fcntl.LOCK_EX | fcntl.LOCK_NB)
    except OSError:
        sys.exit("another ctf_status.py run is still going; skipping this one")
    return fh  # held until the process exits


def main() -> None:
    ap = argparse.ArgumentParser(description=__doc__,
                                 formatter_class=argparse.RawDescriptionHelpFormatter)
    ap.add_argument("-o", "--out", help="write the HedgeDoc markdown to this file")
    ap.add_argument("--stdout", action="store_true", help="print the markdown instead of the summary")
    ap.add_argument("--hedgedoc", metavar="URL",
                    help="POST the markdown to this HedgeDoc instance as a *new* note "
                         "(needs an instance that lets you create notes anonymously)")
    ap.add_argument("--update", metavar="NOTE_URL", nargs="?", const="",
                    help="overwrite an existing HedgeDoc note in place; defaults to "
                         "HEDGEDOC_NOTE from the config. This is the one to cron.")
    ap.add_argument("--challs", action="store_true",
                    help="commit the clone URLs of every Testing Ready+ challenge to "
                         f"CHALLS_PATH (default {DEFAULT_CHALLS_PATH!r}) in the "
                         "deployment repo CHALLS_REPO_URL, if they changed")
    ap.add_argument("--challs-out", metavar="FILE",
                    help="write that challs.txt to a local file instead ('-' for stdout)")
    ap.add_argument("--retries", type=int, default=3,
                    help="attempts at the HedgeDoc write before giving up (default 3)")
    ap.add_argument("--tags", help="YAML front-matter tags for the note "
                                   f"(default {DEFAULT_TAGS!r}, or HEDGEDOC_TAGS)")
    ap.add_argument("--title", help=f"note heading (default {DEFAULT_TITLE!r}, or TITLE)")
    ap.add_argument("-q", "--quiet", action="store_true",
                    help="say nothing unless something changed or broke (for cron)")
    ap.add_argument("--no-color", action="store_true")
    args = ap.parse_args()

    cfg = load_env()
    title = args.title or cfg.get("TITLE") or DEFAULT_TITLE
    tags = args.tags if args.tags is not None else cfg.get("HEDGEDOC_TAGS", DEFAULT_TAGS)

    note_url = None
    if args.update is not None:
        note_url = args.update or cfg.get("HEDGEDOC_NOTE", "")
        if not note_url:
            sys.exit("--update needs a note URL, or HEDGEDOC_NOTE in the config")
        try:
            HedgeDocNote(note_url)  # fail on a typo now, not after the GitLab walk
        except ValueError as e:
            sys.exit(str(e))
    if args.challs and not cfg.get("CHALLS_REPO_URL"):
        sys.exit("--challs needs CHALLS_REPO_URL in the config")
    if note_url or args.challs:
        lock = single_run_lock()  # noqa: F841  (held for the lifetime of the process)

    gl = GitLab(cfg["GITLAB_GROUP_URL"], cfg["GITLAB_TOKEN"])
    try:
        ov = collect(gl)
    except (requests.RequestException, RuntimeError) as e:
        sys.exit(f"reading {cfg['GITLAB_GROUP_URL']} failed: {e}")
    if not ov.challenges and not ov.blank:
        sys.exit(f"no repos found in {cfg['GITLAB_GROUP_URL']!r}")

    md = render_hedgedoc(ov, title, tags)
    if args.out:
        Path(args.out).write_text(md)
    if args.stdout:
        print(md, end="")
    elif not args.quiet:
        print_terminal(ov, c=not args.no_color and sys.stdout.isatty())
        if args.out:
            print(f"markdown → {args.out}")
    if args.hedgedoc:
        print("hedgedoc → " + push_hedgedoc(args.hedgedoc, md))
    challs = render_challs(ov)
    if args.challs_out == "-":
        print(challs, end="")
    elif args.challs_out:
        Path(args.challs_out).write_text(challs)

    # one failing target must not keep the other from being updated
    failed = []
    if note_url:
        try:
            changed = update_hedgedoc(note_url, md, retries=args.retries, quiet=args.quiet)
            if changed or not args.quiet:
                print(("updated → " if changed else "unchanged → ") + note_url)
        except (requests.RequestException, RuntimeError, ValueError, KeyError) as e:
            failed.append(f"hedgedoc update of {note_url} failed: {e}")
    if args.challs:
        repo, path = cfg["CHALLS_REPO_URL"], cfg.get("CHALLS_PATH") or DEFAULT_CHALLS_PATH
        try:
            changed = gl.write_file(repo, path, challs, cfg.get("CHALLS_BRANCH"),
                                    lambda old: challs_message(old, challs, path))
            if changed or not args.quiet:
                print(("committed → " if changed else "unchanged → ") + f"{repo} {path}")
        except (requests.RequestException, RuntimeError, KeyError) as e:
            failed.append(f"challs.txt update in {repo} failed: {e}")
    if failed:
        sys.exit("\n".join(failed))


if __name__ == "__main__":
    main()