"""Voice session: LiveKit + STT/LLM/TTS pipeline.
E2EE via HKDF key derivation (Element Call compatible).
Requires patched livekit-rtc FFI binary from onestacked/livekit-rust-sdks."""
import asyncio
import base64
import datetime
import hashlib
import logging
import os

import zoneinfo

import json
import re

import aiohttp
import httpx
from livekit import rtc, api as lkapi
from livekit.agents import Agent, AgentSession, StopResponse, function_tool, room_io, llm
from livekit.plugins import openai as lk_openai, elevenlabs, silero
from openai import AsyncOpenAI

logger = logging.getLogger("matrix-ai-voice")


LITELLM_URL = os.environ.get("LITELLM_BASE_URL", "")
LITELLM_KEY = os.environ.get("LITELLM_API_KEY", "not-needed")
LK_API_KEY = os.environ.get("LIVEKIT_API_KEY", "")
LK_API_SECRET = os.environ.get("LIVEKIT_API_SECRET", "")
ELEVENLABS_KEY = os.environ.get("ELEVENLABS_API_KEY", "")
BRAVE_API_KEY = os.environ.get("BRAVE_API_KEY", "")
MEMORY_SERVICE_URL = os.environ.get("MEMORY_SERVICE_URL", "http://memory-service:8090")
CONFLUENCE_URL = os.environ.get("CONFLUENCE_BASE_URL", "")
CONFLUENCE_USER = os.environ.get("CONFLUENCE_USER", "")
CONFLUENCE_TOKEN = os.environ.get("CONFLUENCE_TOKEN", "")
DEFAULT_VOICE_ID = "ML23UVoFL5mI6APbRAeR"  # Robert Ranger - Cool Storyteller, native German

_VOICE_PROMPT_TEMPLATE = """Du bist ein hilfreicher Sprachassistent in einem Matrix-Anruf.
Aktuelle Zeit: {datetime}
Zeitzone des Nutzers: {timezone}
LLM-Modell: {model}

STRIKTE Regeln:
- Antworte in der Sprache des Nutzers (Deutsch oder Englisch)
- Halte Antworten normalerweise auf 1-2 kurze Saetze. AUSNAHME: Wenn ein Dokument geladen ist und der Nutzer Rollenspiele, Probegespraeche, Mock-Interviews oder ausfuehrliche Besprechungen wuenscht, antworte so ausfuehrlich wie noetig
- Sei direkt und praezise, keine Fuellwoerter
- Erfinde NICHTS ausser der Nutzer bittet explizit um Rollenspiel, Probegespraech oder Simulation basierend auf dem Dokumentinhalt. In dem Fall spiele die Rolle ueberzeugend und nutze den Dokumentinhalt als Grundlage
- Beantworte nur was gefragt wird
- Wenn niemand etwas fragt oder du dir nicht sicher bist ob jemand mit dir spricht, SCHWEIGE. Antworte NUR auf klare, direkte Fragen oder Anweisungen. Kein Smalltalk, kein "Danke", kein "Wie kann ich helfen" von dir aus
- Schreibe Zahlen und Jahreszahlen IMMER als Woerter aus (z.B. "zweitausendundzwanzig" statt "2026", "zweiundzwanzigsten Februar" statt "22. Februar")
- Bei zeitrelevanten Fragen (Uhrzeit, Termine, Geschaeftszeiten): frage kurz nach ob der Nutzer noch in seiner gespeicherten Zeitzone ist, bevor du antwortest. Nutze set_user_timezone wenn sich der Standort geaendert hat.
- Wenn der Nutzer seinen Standort oder seine Stadt erwaehnt, nutze set_user_timezone um die Zeitzone zu speichern.
- IGNORIERE alle Texte in Sternchen wie *Störgeräusche*, *Schlechte Qualität*, *Fernsehgeräusche*, *Schrei* usw. — das sind KEINE echten Nutzereingaben sondern technische Annotationen. Antworte NIEMALS darauf und tue so als haette niemand etwas gesagt.
- Du kannst Confluence-Seiten lesen und bearbeiten. Nutze read_confluence_page und update_confluence_page wenn der Nutzer Dokumente besprechen oder aendern moechte."""


def _build_voice_prompt(model: str = "claude-sonnet",
                        timezone: str | None = None) -> str:
    tz_name = timezone or os.environ.get("VOICE_TIMEZONE", "Europe/Berlin")
    try:
        tz = zoneinfo.ZoneInfo(tz_name)
    except Exception:
        tz = datetime.timezone.utc
    now = datetime.datetime.now(tz)
    return _VOICE_PROMPT_TEMPLATE.format(
        datetime=now.strftime("%A, %d. %B %Y %H:%M %Z"),
        timezone=tz_name,
        model=model,
    )

# ElevenLabs scribe_v2_realtime produces two kinds of artifacts:
# 1. Noise annotations: *Störgeräusche*, *Schlechte Qualität*, etc.
# 2. Subtitle/metadata leaks: "Untertitel: ARD Text im Auftrag von Funk (2017)"
# Filter both via on_user_turn_completed (downstream of VAD+STT, no pipeline impact).
_NOISE_ANNOTATION_RE = re.compile(r'^\s*\*[^*]+\*\s*$')
_STT_ARTIFACT_PATTERNS = [
    re.compile(r'(?i)^untertitel\b'),           # subtitle metadata
    re.compile(r'(?i)^copyright\b'),            # copyright notices
    re.compile(r'(?i)^musik\s*$'),              # bare "Musik" annotation
    re.compile(r'(?i)^\(.*\)\s*$'),             # parenthetical annotations like (Applaus)
    re.compile(r'(?i)^\[.*\]\s*$'),             # bracketed annotations like [Musik]
    re.compile(r'(?i)^(background noise|static|silence|applause|laughter|noise)\s*$'),  # English variants
    re.compile(r'^\s*\*\*[^*]+\*\*\s*$'),      # double-asterisk: **Noise**
]


_STT_GHOST_PHRASES = {
    "danke", "ja", "nein", "okay", "ok", "tschüss", "hallo", "bye",
    "mhm", "hmm", "aha", "oh", "ah", "ähm", "hm", "tschüss",
    "thanks", "thank you", "yes", "no", "bye bye", "hello", "hi",
    "bitte", "genau", "gut", "so", "na", "ne", "ach", "doch",
    "vielen dank", "alles klar", "schön", "super", "richtig",
}


def _is_stt_artifact(text: str) -> bool:
    """Check if text is an STT artifact (noise annotation, metadata leak, or ghost phrase)."""
    if _NOISE_ANNOTATION_RE.match(text):
        return True
    if any(p.match(text) for p in _STT_ARTIFACT_PATTERNS):
        return True
    # Short phantom transcriptions from ambient noise — ElevenLabs hallucinates
    # common German/English filler words when it hears background sounds
    words = text.split()
    if len(words) <= 2 and text.lower().strip().rstrip(".!?,") in _STT_GHOST_PHRASES:
        return True
    return False


class _NoiseFilterAgent(Agent):
    """Agent that suppresses ElevenLabs STT artifacts before LLM sees them.

    Uses on_user_turn_completed() which runs after VAD+STT, so no backpressure
    risk to the audio pipeline. Raises StopResponse to silently discard noise.
    """

    async def on_user_turn_completed(
        self, turn_ctx: llm.ChatContext, new_message: llm.ChatMessage
    ) -> None:
        text = (new_message.text_content or "").strip()
        if text and _is_stt_artifact(text):
            logger.info("STT artifact suppressed: %s", text)
            # Remove the artifact from context so it doesn't accumulate
            if turn_ctx.items and turn_ctx.items[-1] is new_message:
                turn_ctx.items.pop()
            raise StopResponse()


_vad = None
def _get_vad():
    global _vad
    if _vad is None:
        _vad = silero.VAD.load(
            activation_threshold=0.65,
            min_speech_duration=0.4,
            min_silence_duration=0.55,
        )
    return _vad

def _make_lk_identity(user_id, device_id):
    return f"{user_id}:{device_id}"

def _compute_lk_room_name(room_id):
    raw = f"{room_id}|m.call#ROOM"
    return base64.b64encode(hashlib.sha256(raw.encode()).digest()).decode().rstrip("=")

def _generate_lk_jwt(room_id, user_id, device_id):
    identity = _make_lk_identity(user_id, device_id)
    lk_room = _compute_lk_room_name(room_id)
    token = (
        lkapi.AccessToken(LK_API_KEY, LK_API_SECRET)
        .with_identity(identity)
        .with_name(user_id)
        .with_grants(lkapi.VideoGrants(
            room_join=True, room=lk_room,
            can_publish=True, can_subscribe=True))
        .with_ttl(datetime.timedelta(hours=24))
    )
    logger.info("JWT: identity=%s room=%s", identity, lk_room)
    return token.to_jwt()


KDF_HKDF = 1  # Rust FFI applies HKDF internally (proto enum value 1)
# NOTE: value 0 in the proto is PBKDF2, NOT raw/none mode — see e2ee_patch.py


def _hkdf_derive(ikm: bytes) -> bytes:
    """Pre-derive AES key via HKDF-SHA256 matching livekit-client-sdk-js deriveEncryptionKey().

    JS params: hash=SHA-256, salt=encode("LKFrameEncryptionKey"), info=ArrayBuffer(128), length=128bit
    We set this pre-derived key via set_shared_key() which bypasses Rust FFI KDF entirely.
    """
    import hmac
    salt = b"LKFrameEncryptionKey"
    info = b"\x00" * 128
    prk = hmac.new(salt, ikm, hashlib.sha256).digest()
    t1 = hmac.new(prk, info + b"\x01", hashlib.sha256).digest()
    return t1[:16]


def _ratchet_keys(base_raw: bytes, count: int = 6) -> dict[int, bytes]:
    """Pre-compute ratcheted keys 0..count-1 matching livekit-client-sdk-js ratchet().

    EC JS ratchet: new_raw = HMAC(key=current_raw, data="LKFrameEncryptionKey")[:16]
    Returns {index: raw_key} for all indices 0..count-1.
    Set these via set_key(identity, raw, index) with KDF_HKDF=1 so Rust applies HKDF.
    """
    import hmac as _hmac
    keys = {}
    raw = base_raw
    for i in range(count):
        keys[i] = raw
        raw = _hmac.new(raw, b"LKFrameEncryptionKey", hashlib.sha256).digest()[:16]
    return keys


async def _brave_search(query: str, count: int = 5) -> str:
    """Call Brave Search API and return formatted results."""
    if not BRAVE_API_KEY:
        return "Search unavailable (no API key configured)."
    try:
        async with httpx.AsyncClient(timeout=10.0) as client:
            resp = await client.get(
                "https://api.search.brave.com/res/v1/web/search",
                headers={"Accept": "application/json", "X-Subscription-Token": BRAVE_API_KEY},
                params={"q": query, "count": count, "text_decorations": False},
            )
            resp.raise_for_status()
            data = resp.json()
        results = data.get("web", {}).get("results", [])
        if not results:
            return "No results found."
        lines = []
        for r in results[:count]:
            lines.append(f"- {r.get('title', '')}: {r.get('description', '')} ({r.get('url', '')})")
        return "\n".join(lines)
    except Exception as exc:
        logger.warning("Brave search error: %s", exc)
        return f"Search failed: {exc}"


async def _store_user_pref(user_id: str, key: str, value: str) -> None:
    """Store a user preference in memory (e.g. timezone, language)."""
    if not MEMORY_SERVICE_URL:
        return
    fact = f"[PREF:{key}] {value}"
    try:
        async with httpx.AsyncClient(timeout=10.0) as client:
            await client.post(
                f"{MEMORY_SERVICE_URL}/memories/store",
                json={"user_id": user_id, "fact": fact, "source_room": "preferences"},
            )
            logger.info("Preference stored for %s: %s=%s", user_id, key, value)
    except Exception as exc:
        logger.warning("Preference store failed: %s", exc)


async def _store_voice_exchange(user_text: str, agent_text: str,
                                user_id: str, room_id: str) -> None:
    """Store the full conversation exchange as memory (no LLM extraction)."""
    if not MEMORY_SERVICE_URL:
        return
    exchange = f"User: {user_text}\nAssistant: {agent_text}"
    try:
        async with httpx.AsyncClient(timeout=10.0) as client:
            await client.post(
                f"{MEMORY_SERVICE_URL}/memories/store",
                json={"user_id": user_id, "fact": exchange, "source_room": room_id},
            )
            logger.info("Memory stored for %s: %s", user_id, exchange[:120])
    except Exception as exc:
        logger.warning("Voice memory store failed: %s", exc)


async def _confluence_read_page(page_id: str) -> tuple[str, str, int]:
    """Read a Confluence page and return (title, plain_text, version_number)."""
    if not CONFLUENCE_URL or not CONFLUENCE_USER or not CONFLUENCE_TOKEN:
        raise RuntimeError("Confluence credentials not configured")
    url = f"{CONFLUENCE_URL}/rest/api/content/{page_id}"
    params = {"expand": "body.storage,version,title"}
    async with httpx.AsyncClient(timeout=15.0) as client:
        resp = await client.get(
            url,
            params=params,
            auth=(CONFLUENCE_USER, CONFLUENCE_TOKEN),
        )
        resp.raise_for_status()
        data = resp.json()
    title = data.get("title", "")
    version = data.get("version", {}).get("number", 1)
    html = data.get("body", {}).get("storage", {}).get("value", "")
    # Strip HTML tags to plain text for voice readback
    plain = re.sub(r"<[^>]+>", " ", html)
    plain = re.sub(r"\s+", " ", plain).strip()
    return title, plain, version


async def _confluence_update_section(page_id: str, section_heading: str, new_html: str) -> str:
    """Update a section of a Confluence page by heading.

    Finds the section by heading, replaces content up to next same-level heading,
    PUTs with incremented version.
    """
    if not CONFLUENCE_URL or not CONFLUENCE_USER or not CONFLUENCE_TOKEN:
        return "Confluence credentials not configured."
    # Read current page
    url = f"{CONFLUENCE_URL}/rest/api/content/{page_id}"
    params = {"expand": "body.storage,version,title"}
    async with httpx.AsyncClient(timeout=15.0) as client:
        resp = await client.get(url, params=params, auth=(CONFLUENCE_USER, CONFLUENCE_TOKEN))
        resp.raise_for_status()
        data = resp.json()

    title = data["title"]
    version = data["version"]["number"]
    body_html = data["body"]["storage"]["value"]

    # Find section by heading (h1-h6) and replace content up to next same-level heading
    heading_pattern = re.compile(
        r'(<h([1-6])[^>]*>.*?' + re.escape(section_heading) + r'.*?</h\2>)',
        re.IGNORECASE | re.DOTALL,
    )
    match = heading_pattern.search(body_html)
    if not match:
        return f"Section '{section_heading}' not found on page."

    heading_tag = match.group(0)
    heading_level = match.group(2)
    section_start = match.end()

    # Find next heading of same or higher level
    next_heading = re.compile(
        rf'<h[1-{heading_level}][^>]*>',
        re.IGNORECASE,
    )
    next_match = next_heading.search(body_html, section_start)
    section_end = next_match.start() if next_match else len(body_html)

    # Replace section content
    new_body = body_html[:section_start] + new_html + body_html[section_end:]

    # PUT updated page
    put_data = {
        "version": {"number": version + 1},
        "title": title,
        "type": "page",
        "body": {
            "storage": {
                "value": new_body,
                "representation": "storage",
            }
        },
    }
    async with httpx.AsyncClient(timeout=15.0) as client:
        resp = await client.put(
            url,
            json=put_data,
            auth=(CONFLUENCE_USER, CONFLUENCE_TOKEN),
        )
        resp.raise_for_status()
    return f"Section '{section_heading}' updated successfully."


def _build_e2ee_options() -> rtc.E2EEOptions:
    """Build E2EE options — let Rust FFI apply HKDF internally (KDF_HKDF=1).

    Pass raw base keys from Matrix key exchange events directly to set_key().
    The Rust FFI derives the AES frame key via HKDF(base_key, ratchetSalt, ...) internally.
    Element Call uses: ratchetWindowSize=10, keyringSize=256, ratchetSalt="LKFrameEncryptionKey"
    NOTE: proto value 0 = PBKDF2 (not raw/none) — must use KDF_HKDF=1.
    """
    key_opts = rtc.KeyProviderOptions(
        shared_key=b"",  # empty = per-participant mode
        ratchet_window_size=10,
        ratchet_salt=b"LKFrameEncryptionKey",
        failure_tolerance=10,
        key_ring_size=256,
        key_derivation_function=KDF_HKDF,  # Rust FFI applies HKDF; we pass raw base keys
    )
    return rtc.E2EEOptions(
        encryption_type=rtc.EncryptionType.GCM,
        key_provider_options=key_opts,
    )


class VoiceSession:
    def __init__(self, nio_client, room_id, device_id, lk_url, model="claude-sonnet",
                 publish_key_cb=None, bot_key: bytes | None = None,
                 memory=None, caller_user_id: str | None = None,
                 document_context: str | None = None):
        self.nio_client = nio_client
        self.room_id = room_id
        self.device_id = device_id
        self.lk_url = lk_url
        self.model = model
        self.lk_room = None
        self.session = None
        self._task = None
        self._http_session = None
        self._caller_key: bytes | None = None
        self._caller_identity: str | None = None
        self._caller_all_keys: dict = {}  # {index: bytes} — all caller keys by index
        self._bot_key: bytes = bot_key or os.urandom(16)
        self._publish_key_cb = publish_key_cb
        self._memory = memory          # MemoryClient instance from bot.py
        self._caller_user_id = caller_user_id  # Matrix user ID for memory lookup
        self._document_context = document_context  # PDF text from room for voice context
        self._transcript: list[dict] = []  # {"role": "user"|"assistant", "text": "..."}

    def on_encryption_key(self, sender, device_id, key, index):
        """Receive E2EE key from Element Call participant.

        Store-only: keys are applied in on_track_subscribed() / on_e2ee_state_changed()
        where the frame cryptor is guaranteed to exist.  If the track is already
        subscribed (late key arrival / rotation), set the key immediately.
        """
        if not key:
            return
        if not self._caller_key:
            self._caller_key = key
            self._caller_identity = f"{sender}:{device_id}"
        self._caller_all_keys[index] = key
        logger.info("E2EE key received from %s:%s (index=%d, %d bytes, raw=%s)",
                    sender, device_id, index, len(key), key.hex())
        # Late key arrival: if track already subscribed, frame cryptor exists — set key now.
        if self.lk_room and self._caller_identity:
            caller_lk_id = self._caller_identity
            for p in self.lk_room.remote_participants.values():
                if p.identity == caller_lk_id:
                    has_subscribed = any(
                        pub.subscribed for pub in p.track_publications.values()
                    )
                    if has_subscribed:
                        try:
                            kp = self.lk_room.e2ee_manager.key_provider
                            ok = kp.set_key(p.identity, key, index)
                            logger.info("Late key set_key[%d] for %s (ok=%s)",
                                        index, p.identity, ok)
                        except Exception as e:
                            logger.warning("Late key set_key failed: %s", e)
                    break

    async def _fetch_encryption_key_http(self) -> bytes | None:
        """Fetch encryption key from room timeline (NOT state) via Matrix HTTP API.

        Element Call distributes encryption keys as timeline events, not state.
        """
        import httpx
        homeserver = str(self.nio_client.homeserver)
        token = self.nio_client.access_token
        url = f"{homeserver}/_matrix/client/v3/rooms/{self.room_id}/messages"
        try:
            async with httpx.AsyncClient(timeout=10.0) as http:
                resp = await http.get(
                    url,
                    headers={"Authorization": f"Bearer {token}"},
                    params={"dir": "b", "limit": "50"},
                )
                resp.raise_for_status()
                data = resp.json()
                events = data.get("chunk", [])
                user_id = self.nio_client.user_id
                for evt in events:
                    evt_type = evt.get("type", "")
                    if evt_type == "io.element.call.encryption_keys":
                        sender = evt.get("sender", "")
                        if sender == user_id:
                            continue  # skip our own key
                        content = evt.get("content", {})
                        device = content.get("device_id", "")
                        logger.info("Found encryption_keys timeline event: sender=%s device=%s",
                                    sender, device)
                        all_keys = {}
                        import base64 as b64
                        for k in content.get("keys", []):
                            key_b64 = k.get("key", "")
                            key_index = k.get("index", 0)
                            if key_b64:
                                key_b64 += "=" * (-len(key_b64) % 4)
                                key_bytes = b64.urlsafe_b64decode(key_b64)
                                all_keys[key_index] = key_bytes
                        if all_keys:
                            if device:
                                self._caller_identity = f"{sender}:{device}"
                            self._caller_all_keys.update(all_keys)
                            max_idx = max(all_keys.keys())
                            logger.info("Loaded caller keys at indices %s (using %d)",
                                        sorted(all_keys.keys()), max_idx)
                            return all_keys[max_idx]
                logger.info("No encryption_keys events in last %d timeline events", len(events))
        except Exception as e:
            logger.warning("HTTP encryption key fetch failed: %s", e)
        return None

    async def start(self):
        self._task = asyncio.create_task(self._run())

    async def stop(self):
        for obj in [self.session, self.lk_room, self._http_session]:
            if obj:
                try:
                    if hasattr(obj, "aclose"):
                        await obj.aclose()
                    elif hasattr(obj, "disconnect"):
                        await obj.disconnect()
                    elif hasattr(obj, "close"):
                        await obj.close()
                except Exception:
                    pass
        if self._task and not self._task.done():
            self._task.cancel()
            try:
                await self._task
            except asyncio.CancelledError:
                pass

    def get_transcript(self) -> list[dict]:
        """Return the call transcript as a list of {role, text} dicts."""
        return list(self._transcript)

    def get_document_context(self) -> str | None:
        """Return the document context loaded for this call, if any."""
        return self._document_context

    def get_confluence_page_id(self) -> str | None:
        """Return the active Confluence page ID, if any."""
        if not self._document_context:
            return None
        ids = re.findall(r'confluence_page_id:(\d+)', self._document_context)
        return ids[0] if ids else None

    async def _run(self):
        try:
            user_id = self.nio_client.user_id
            bot_identity = _make_lk_identity(user_id, self.device_id)
            jwt = _generate_lk_jwt(self.room_id, user_id, self.device_id)

            # Publish bot's own key immediately so Element Call can decrypt us
            if self._publish_key_cb:
                self._publish_key_cb(self._bot_key)
                logger.info("Published bot E2EE key (%d bytes)", len(self._bot_key))

            # Check timeline for caller's encryption key
            caller_key = await self._fetch_encryption_key_http()
            if caller_key:
                self._caller_key = caller_key
                logger.info("Got caller E2EE key via timeline (%d bytes)", len(caller_key))

            if not self._caller_key:
                # Wait up to 15s for key via sync handler
                logger.info("No key in timeline yet, waiting for sync...")
                for _ in range(150):
                    if self._caller_key:
                        break
                    await asyncio.sleep(0.1)

            # E2EE: configurable via E2EE_ENABLED env var (default true).
            # When enabled, parameters MUST match Element Call JS SDK.
            e2ee_enabled = os.environ.get("E2EE_ENABLED", "true").lower() in ("true", "1", "yes")
            if e2ee_enabled:
                e2ee_opts = _build_e2ee_options()
                room_opts = rtc.RoomOptions(e2ee=e2ee_opts)
                logger.info("E2EE enabled (HKDF mode)")
            else:
                e2ee_opts = None
                room_opts = rtc.RoomOptions()
                logger.warning("E2EE DISABLED — audio is unencrypted")
            self.lk_room = rtc.Room()

            @self.lk_room.on("participant_connected")
            def on_p(p):
                logger.info("Participant connected: %s", p.identity)
                # Note: do NOT set keys here — frame cryptor not initialized yet at participant_connected.
                # Keys are set in on_track_subscribed where the frame cryptor definitely exists.

            @self.lk_room.on("track_published")
            def on_tp(pub, p):
                logger.info("Track pub: %s %s kind=%s", p.identity, pub.sid, pub.kind)

            @self.lk_room.on("track_muted")
            def on_mute(p, pub):
                logger.info("Track MUTED: %s %s kind=%s", p.identity, pub.sid, pub.kind)

            @self.lk_room.on("track_unmuted")
            def on_unmute(p, pub):
                logger.info("Track UNMUTED: %s %s kind=%s", p.identity, pub.sid, pub.kind)

            @self.lk_room.on("track_subscribed")
            def on_ts(t, pub, p):
                logger.info("Track sub: %s %s kind=%s muted=%s", p.identity, pub.sid, t.kind, pub.muted)
                # NOTE: Do NOT create rtc.AudioStream here — it competes with AgentSession's
                # internal audio pipeline for event loop time, causing intermittent VAD failures
                # (user_state stuck on "away"). See MAT-40. Use e2ee_state_changed for flow confirmation.
                # *** KEY FIX: set_key() with KDF_HKDF only applies HKDF when the frame cryptor
                # for this participant already exists. The frame cryptor is created at track
                # subscription time. Calling set_key() BEFORE track subscription (at connect)
                # skips HKDF derivation → raw key stored → DEC_FAILED.
                # Solution: set caller key HERE, after frame cryptor is initialized.
                if int(t.kind) == 1 and e2ee_opts is not None:  # audio track only
                    caller_id = p.identity
                    logger.info("E2EE_DIAG: track_subscribed for %s, have %d caller keys",
                                caller_id, len(self._caller_all_keys))
                    try:
                        kp_local = self.lk_room.e2ee_manager.key_provider
                        if self._caller_all_keys:
                            for idx, base_k in sorted(self._caller_all_keys.items()):
                                ok = kp_local.set_key(caller_id, base_k, idx)
                                logger.info("on_ts: set_key[%d] for %s (ok=%s, %d bytes, raw=%s)",
                                            idx, caller_id, ok, len(base_k), base_k.hex())
                        else:
                            logger.warning("on_ts: no caller keys yet — scheduling 0.5s retry")
                            async def _brief_key_retry(pid=caller_id):
                                await asyncio.sleep(0.5)
                                if self._caller_all_keys:
                                    try:
                                        kp_r = self.lk_room.e2ee_manager.key_provider
                                        for idx, base_k in sorted(self._caller_all_keys.items()):
                                            ok = kp_r.set_key(pid, base_k, idx)
                                            logger.info("on_ts_retry: set_key[%d] for %s (ok=%s)", idx, pid, ok)
                                    except Exception as exc:
                                        logger.warning("on_ts_retry: set_key failed: %s", exc)
                                else:
                                    logger.warning("on_ts_retry: still no caller keys for %s", pid)
                            asyncio.ensure_future(_brief_key_retry())
                    except Exception as exc:
                        logger.warning("on_ts: set_key failed: %s", exc)

            _e2ee_state_names = {0:"NEW",1:"OK",2:"ENC_FAILED",3:"DEC_FAILED",4:"MISSING_KEY",5:"RATCHETED",6:"INTERNAL_ERR"}
            @self.lk_room.on("e2ee_state_changed")
            def on_e2ee_state(participant, state):
                state_name = _e2ee_state_names.get(int(state), f"UNKNOWN_{state}")
                p_id = participant.identity if participant else "local"
                logger.info("E2EE_STATE: participant=%s state=%s", p_id, state_name)
                # When remote participant frame cryptor is NEW or MISSING_KEY → set their key
                if participant and p_id != bot_identity and int(state) in (0, 3, 4):
                    if self._caller_all_keys:
                        try:
                            kp_e = self.lk_room.e2ee_manager.key_provider
                            for idx, base_k in sorted(self._caller_all_keys.items()):
                                ok = kp_e.set_key(p_id, base_k, idx)
                                logger.info("e2ee_state set_key[%d] for %s (ok=%s)", idx, p_id, ok)
                        except Exception as exc:
                            logger.warning("e2ee_state set_key failed: %s", exc)

            await self.lk_room.connect(self.lk_url, jwt, options=room_opts)
            logger.info("Connected (E2EE=HKDF), remote=%d",
                        len(self.lk_room.remote_participants))

            # Set bot's own key immediately after connect — local frame cryptor exists at connect time.
            # CALLER keys are set in on_track_subscribed (NOT here) because the caller's frame cryptor
            # is only created when their track arrives. Calling set_key() before that skips HKDF.
            kp = self.lk_room.e2ee_manager.key_provider
            ok = kp.set_key(bot_identity, self._bot_key, 0)
            logger.info("Set bot key for %s (ok=%s, %d bytes)", bot_identity, ok, len(self._bot_key))

            # Element Call rotates its key when bot joins. Wait up to 3s for the
            # rotated key to arrive via nio sync before proceeding.  If it arrives,
            # on_encryption_key() stores it and (if track already subscribed) sets it.
            pre_key_count = len(self._caller_all_keys)
            pre_max_idx = max(self._caller_all_keys.keys()) if self._caller_all_keys else -1
            logger.info("Waiting up to 3s for key rotation (current: %d keys, max_idx=%d)...",
                        pre_key_count, pre_max_idx)
            for _wait in range(6):  # 6 × 0.5s = 3s
                await asyncio.sleep(0.5)
                new_count = len(self._caller_all_keys)
                new_max = max(self._caller_all_keys.keys()) if self._caller_all_keys else -1
                if new_max > pre_max_idx or new_count > pre_key_count:
                    self._caller_key = self._caller_all_keys[new_max]
                    logger.info("Key rotated: index %d→%d, count %d→%d",
                                pre_max_idx, new_max, pre_key_count, new_count)
                    break
            else:
                logger.info("No key rotation after 3s — proceeding with key[%d]", pre_max_idx)

            # Find the remote participant, wait up to 10s if not yet connected
            remote_identity = None
            for p in self.lk_room.remote_participants.values():
                remote_identity = p.identity
                break
            if not remote_identity:
                logger.info("No remote participant yet, waiting...")
                for _ in range(100):
                    await asyncio.sleep(0.1)
                    for p in self.lk_room.remote_participants.values():
                        remote_identity = p.identity
                        break
                    if remote_identity:
                        break

            # Set shared_key with pre-derived AES key for caller decryption.
            # NOT using set_key() for caller — Rust HKDF may produce different result than EC's JS HKDF.
            # set_shared_key() stores key raw (no KDF applied) — we pre-derive in Python.
            # After key rotation wait: if track already subscribed, set rotated key.
            # (Usually on_track_subscribed handles this, but if track arrived before rotation,
            # the rotated key needs to be set here for the already-subscribed participant.)
            if self._caller_all_keys and remote_identity:
                try:
                    for idx, base_k in sorted(self._caller_all_keys.items()):
                        ok = kp.set_key(remote_identity, base_k, idx)
                        logger.info("Post-rotation set_key[%d] for %s (ok=%s)",
                                    idx, remote_identity, ok)
                except Exception as e:
                    logger.warning("Post-rotation set_key failed: %s", e)
            elif not self._caller_all_keys:
                logger.warning("No caller E2EE keys received — incoming audio will be silence")

            if remote_identity:
                logger.info("Linking to remote participant: %s", remote_identity)

            # Load memories and user preferences for this caller
            memory_section = ""
            user_timezone = None
            if self._memory and self._caller_user_id:
                try:
                    mems = await self._memory.query(self._caller_user_id, "voice call", top_k=10)
                    if mems:
                        conversations = []
                        for m in mems:
                            fact = m['fact']
                            # Extract timezone preference from stored memories
                            if fact.startswith("[PREF:timezone]"):
                                user_timezone = fact.split("]", 1)[1].strip()
                            else:
                                conversations.append(fact)
                        if conversations:
                            memory_section = "\n\nFrühere Gespräche mit diesem Nutzer:\n" + \
                                "\n---\n".join(conversations)
                        logger.info("Loaded %d memories for %s (tz=%s)",
                                    len(mems), self._caller_user_id, user_timezone)
                except Exception as exc:
                    logger.warning("Memory query failed: %s", exc)
            # Also query specifically for timezone preference if not found above
            if not user_timezone and self._memory and self._caller_user_id:
                try:
                    tz_mems = await self._memory.query(
                        self._caller_user_id, "timezone preference", top_k=3)
                    for m in (tz_mems or []):
                        if m['fact'].startswith("[PREF:timezone]"):
                            user_timezone = m['fact'].split("]", 1)[1].strip()
                            break
                except Exception:
                    pass

            # Voice pipeline — Jack Marlowe (native German male)
            self._http_session = aiohttp.ClientSession()
            voice_id = os.environ.get("ELEVENLABS_VOICE_ID", DEFAULT_VOICE_ID)
            self.session = AgentSession(
                stt=elevenlabs.STT(
                    api_key=ELEVENLABS_KEY,
                    model_id="scribe_v2_realtime",
                    language_code=os.environ.get("STT_LANGUAGE", "de"),
                    http_session=self._http_session,
                ),
                llm=lk_openai.LLM(base_url=LITELLM_URL, api_key=LITELLM_KEY, model=self.model),
                tts=elevenlabs.TTS(
                    voice_id=voice_id,
                    model="eleven_multilingual_v2",
                    language="de",
                    api_key=ELEVENLABS_KEY,
                    voice_settings=elevenlabs.VoiceSettings(
                        stability=0.5, similarity_boost=0.75, speed=1.15,
                    ),
                    http_session=self._http_session,
                ),
                vad=_get_vad(),
            )

            # Pipeline event logging (livekit-agents 1.4.2 event names)
            _vad_state_log: dict = {"last": None, "speaking_count": 0, "away_since": None}

            @self.session.on("user_state_changed")
            def _on_user_state(ev):
                state = ev.new_state
                prev = _vad_state_log["last"]
                _vad_state_log["last"] = state
                if str(state) == "speaking":
                    _vad_state_log["speaking_count"] = _vad_state_log.get("speaking_count", 0) + 1
                    _vad_state_log["away_since"] = None
                    logger.info("VAD: user_state=%s (speaking_count=%d)", state, _vad_state_log["speaking_count"])
                elif str(state) == "away" and prev and str(prev) != "away":
                    import time
                    _vad_state_log["away_since"] = time.monotonic()
                    logger.info("VAD: user_state=%s (was %s)", state, prev)
                else:
                    logger.info("VAD: user_state=%s", state)

            _last_user_speech: list[str] = []

            @self.session.on("user_input_transcribed")
            def _on_user_speech(ev):
                text = ev.transcript or ""
                if text and _is_stt_artifact(text):
                    logger.warning("NOISE_LEAK: artifact reached STT: %s", text)
                else:
                    logger.info("USER_SPEECH: %s", text)
                if ev.transcript:
                    _last_user_speech.append(ev.transcript)
                    self._transcript.append({"role": "user", "text": ev.transcript})

            @self.session.on("conversation_item_added")
            def _on_conversation_item(ev):
                role = getattr(ev.item, "role", "?")
                text = getattr(ev.item, "text_content", "") or ""
                if role == "assistant" and text:
                    logger.info("AGENT_SPEECH: %s", text)
                    self._transcript.append({"role": "assistant", "text": text})
                    if self._memory and self._caller_user_id and _last_user_speech:
                        user_text = " ".join(_last_user_speech)
                        _last_user_speech.clear()
                        asyncio.ensure_future(
                            _store_voice_exchange(user_text, text,
                                                  self._caller_user_id, self.room_id))

            # Brave Search tool — lets the agent answer questions about current events
            @function_tool
            async def search_web(query: str) -> str:
                """Search the web for current information using Brave Search.

                Use this when asked about recent news, current events, prices,
                weather, or any information that may have changed recently.
                """
                logger.info("SEARCH: %s", query)
                result = await _brave_search(query)
                logger.info("SEARCH_RESULT: %s", result[:200])
                return result

            # Tool: set user timezone — called by the LLM when user mentions their location
            caller_uid = self._caller_user_id

            @function_tool
            async def set_user_timezone(iana_timezone: str) -> str:
                """Store the user's timezone. Call this when the user mentions their city
                or timezone (e.g. 'I'm in Nicosia' → 'Europe/Nicosia',
                'I live in New York' → 'America/New_York').
                Use IANA timezone names like Europe/Berlin, America/New_York, Asia/Tokyo.
                """
                if caller_uid:
                    await _store_user_pref(caller_uid, "timezone", iana_timezone)
                return f"Timezone set to {iana_timezone}"

            # Extract active Confluence page ID from document context (if any)
            _active_conf_id = None
            if self._document_context:
                _conf_ids = re.findall(r'confluence_page_id:(\d+)', self._document_context)
                if _conf_ids:
                    _active_conf_id = _conf_ids[0]

            @function_tool
            async def read_confluence_page(page_id: str = "") -> str:
                """Read a Confluence page. Use when user asks to read, review,
                or check a document. Returns page title and content as text.
                Leave page_id empty to use the active document from the room."""
                pid = page_id or _active_conf_id
                if not pid:
                    return "No Confluence page ID available. Ask the user to share a Confluence link first."
                logger.info("CONFLUENCE_READ: page_id=%s", pid)
                try:
                    title, text, _ver = await _confluence_read_page(pid)
                    result = f"Page: {title}\n\n{text}"
                    logger.info("CONFLUENCE_READ_OK: %s (%d chars)", title, len(text))
                    return result
                except Exception as exc:
                    logger.warning("CONFLUENCE_READ_FAIL: %s", exc)
                    return f"Failed to read page: {exc}"

            @function_tool
            async def update_confluence_page(section_heading: str, new_content: str, page_id: str = "") -> str:
                """Update a section of a Confluence page. Use when user asks to
                change, update, or rewrite part of a document.
                - section_heading: heading text of the section to update
                - new_content: new plain text for the section (will be wrapped in <p> tags)
                - page_id: leave empty to use the active document from the room
                Human sees changes instantly in their browser via Live Docs."""
                pid = page_id or _active_conf_id
                if not pid:
                    return "No Confluence page ID available. Ask the user to share a Confluence link first."
                logger.info("CONFLUENCE_UPDATE: page=%s section='%s'", pid, section_heading)
                try:
                    new_html = f"<p>{new_content}</p>"
                    result = await _confluence_update_section(pid, section_heading, new_html)
                    logger.info("CONFLUENCE_UPDATE_OK: %s", result)
                    return result
                except Exception as exc:
                    logger.warning("CONFLUENCE_UPDATE_FAIL: %s", exc)
                    return f"Failed to update page: {exc}"

            instructions = _build_voice_prompt(model=self.model, timezone=user_timezone) + memory_section
            if self._document_context:
                instructions += f"\n\nDokument-Kontext (im Raum hochgeladen):\n{self._document_context}"
                if _active_conf_id:
                    instructions += f"\n\nAktive Confluence-Seite: {_active_conf_id}. Du brauchst den Nutzer NICHT nach der page_id zu fragen — nutze automatisch diese ID fuer read_confluence_page und update_confluence_page."
            agent = _NoiseFilterAgent(
                instructions=instructions,
                tools=[search_web, set_user_timezone, read_confluence_page, update_confluence_page],
            )
            io_opts = room_io.RoomOptions(
                participant_identity=remote_identity,
                close_on_disconnect=False,
            ) if remote_identity else room_io.RoomOptions(close_on_disconnect=False)
            await self.session.start(
                agent=agent,
                room=self.lk_room,
                room_options=io_opts,
            )
            logger.info("Voice pipeline started (voice=%s, linked_to=%s)", voice_id, remote_identity)

            try:
                await asyncio.wait_for(
                    self.session.generate_reply(
                        instructions="Sage nur: Hallo, wie kann ich helfen?"),
                    timeout=30.0)
                logger.info("Greeting sent")
            except asyncio.TimeoutError:
                logger.error("Greeting timed out")

            # VAD watchdog: log diagnostic and attempt E2EE key recovery if stuck
            import time as _time
            while True:
                await asyncio.sleep(10)
                away_since = _vad_state_log.get("away_since")
                if away_since and (_time.monotonic() - away_since) > 30:
                    sc = _vad_state_log.get("speaking_count", 0)
                    e2ee_ok = any(
                        str(getattr(p, '_e2ee_state', '')) == 'OK'
                        for p in self.lk_room.remote_participants.values()
                    ) if self.lk_room else False
                    n_remote = len(self.lk_room.remote_participants) if self.lk_room else 0
                    logger.warning(
                        "VAD_WATCHDOG: user_state=away for >30s (speaking_count=%d, "
                        "remote_participants=%d, e2ee_ok=%s) — attempting E2EE key recovery",
                        sc, n_remote, e2ee_ok,
                    )
                    # Recovery: re-apply all stored E2EE keys for all remote participants
                    if self.lk_room and self._caller_all_keys:
                        try:
                            kp_w = self.lk_room.e2ee_manager.key_provider
                            for p in self.lk_room.remote_participants.values():
                                for idx, base_k in sorted(self._caller_all_keys.items()):
                                    ok = kp_w.set_key(p.identity, base_k, idx)
                                    logger.info("VAD_WATCHDOG: recovery set_key[%d] for %s (ok=%s)",
                                                idx, p.identity, ok)
                        except Exception as exc:
                            logger.warning("VAD_WATCHDOG: recovery set_key failed: %s", exc)
                    _vad_state_log["away_since"] = None  # only warn once per stuck period

        except asyncio.CancelledError:
            logger.info("Session cancelled for %s", self.room_id)
        except Exception:
            logger.exception("Session failed for %s", self.room_id)