import asyncio
import json
import logging

from fastapi import APIRouter, BackgroundTasks, HTTPException, Request, Response

from auth_utils import get_user_channels
from context_loader import load_context
from llm_client import complete
from notification import _send_nct_message
from persona import set_context
from session_logger import log_turn
from session_store import load as load_session, save as save_session
from config import settings
import event_bus

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
if not logger.handlers:
    _h = logging.StreamHandler()
    _h.setFormatter(logging.Formatter("%(levelname)s:%(name)s: %(message)s"))
    logger.addHandler(_h)
    logger.propagate = False

router = APIRouter()


def _verify_signature(body: bytes, random_header: str, sig_header: str, secret: str) -> bool:
    """Nextcloud signs requests with HMAC-SHA256(key=secret, msg=random+body)."""
    expected = hmac.new(
        secret.encode(),
        (random_header + body.decode("utf-8", errors="replace")).encode(),
        hashlib.sha256,
    ).hexdigest()
    return hmac.compare_digest(expected, sig_header.lower())


async def _send_reply(conversation_token: str, message: str, nextcloud_url: str, secret: str) -> None:
    """Post a message to Nextcloud Talk as the bot."""
    logger.info("NCT _send_reply → room %s (%d chars)", conversation_token, len(message))
    await _send_nct_message(nextcloud_url, secret, conversation_token, message)


async def _process_message(
    conversation_token: str,
    user_text: str,
    actor_name: str,
    username: str,
    persona_name: str,
    nextcloud_url: str,
    secret: str,
    timeout: int,
) -> None:
    logger.info("NCT process: token=%s user=%s text=%r", conversation_token, actor_name, user_text)

    set_context(username, persona_name)

    session_id    = f"nct_{username}_{conversation_token}"
    system_prompt = load_context(settings.default_tier)
    history       = load_session(session_id)
    history.append({"role": "user", "content": user_text})

    await event_bus.publish({
        "type": "nct_message",
        "session_id": session_id,
        "role": "user",
        "content": user_text,
        "actor": actor_name,
    })

    try:
        response_text, backend = await asyncio.wait_for(
            complete(system_prompt=system_prompt, messages=history),
            timeout=timeout,
        )
    except asyncio.TimeoutError:
        logger.warning("NCT timeout for %s", conversation_token)
        await _send_reply(conversation_token, "⏳ Still thinking — this is taking longer than usual.", nextcloud_url, secret)
        return
    except Exception as e:
        logger.error("NCT LLM error for %s: %s", conversation_token, e)
        await _send_reply(conversation_token, "⚠️ Something went wrong on my end.", nextcloud_url, secret)
        return

    logger.info("NCT LLM responded via %s (%d chars)", backend, len(response_text))
    history.append({"role": "assistant", "content": response_text})
    save_session(session_id, history)
    log_turn(session_id, user_text, response_text)

    await event_bus.publish({
        "type": "nct_response",
        "session_id": session_id,
        "role": "assistant",
        "content": response_text,
        "backend": backend,
    })

    await _send_reply(conversation_token, response_text, nextcloud_url, secret)


@router.post("/webhook/nextcloud/{username}")
async def nextcloud_talk_webhook(username: str, request: Request, background_tasks: BackgroundTasks):
    channels = get_user_channels(username)
    cfg = channels.get("nextcloud")
    if not cfg:
        logger.warning("NCT webhook: no channel config for user %r", username)
        raise HTTPException(status_code=404, detail="Channel not configured for this user")

    persona_name  = cfg.get("persona", "inara")
    nextcloud_url = cfg.get("url", "")
    secret        = cfg.get("bot_secret", "")
    timeout       = cfg.get("timeout", 55)

    if not secret:
        logger.error("NCT webhook: bot_secret missing for user %r", username)
        return Response(status_code=500)

    body = await request.body()

    random_header = request.headers.get("X-Nextcloud-Talk-Random", "")
    sig_header    = request.headers.get("X-Nextcloud-Talk-Signature", "")

    if not _verify_signature(body, random_header, sig_header, secret):
        logger.warning("NCT webhook: signature mismatch for %s", username)
        raise HTTPException(status_code=401, detail="Invalid signature")

    try:
        payload = json.loads(body)
    except json.JSONDecodeError:
        raise HTTPException(status_code=400, detail="Invalid JSON")

    if payload.get("type") != "Create":
        return Response(status_code=200)

    obj = payload.get("object", {})
    if obj.get("type") != "Note":
        return Response(status_code=200)

    actor  = payload.get("actor", {})
    target = payload.get("target", {})

    if actor.get("type") == "bots":
        return Response(status_code=200)

    conversation_token = target.get("id", "")

    try:
        content   = json.loads(obj.get("content", "{}"))
        user_text = content.get("message", "").strip()
    except (json.JSONDecodeError, AttributeError):
        user_text = (obj.get("name") or obj.get("content", "")).strip()

    mention_prefix = f"@{persona_name.lower()}"
    if user_text.lower().startswith(mention_prefix):
        user_text = user_text[len(mention_prefix):].strip()

    if not user_text:
        return Response(status_code=200)

    actor_name = actor.get("name", "User")
    logger.info("NCT message from %s in %s: %r", actor_name, conversation_token, user_text[:60])

    background_tasks.add_task(
        _process_message,
        conversation_token, user_text, actor_name,
        username, persona_name, nextcloud_url, secret, timeout,
    )
    return Response(status_code=200)