from __future__ import annotations

import asyncio
import logging
import os

from fastapi import APIRouter, Header, Request
from fastapi.responses import JSONResponse, PlainTextResponse

from yuxi.channel.extensions.kakaotalk.config import KakaoTalkConfigAdapter, ENV_KAKAO_ADMIN_KEY
from yuxi.channel.extensions.kakaotalk.dedupe import KakaoTalkDeduplicator, build_dedupe_key
from yuxi.channel.extensions.kakaotalk.monitor import KakaoTalkMonitor

logger = logging.getLogger(__name__)

MAX_BODY_BYTES = 64 * 1024
BODY_TIMEOUT_S = 5.0

router = APIRouter(prefix="/webhook/kakaotalk", tags=["kakaotalk"])


class KakaoTalkWebhookHandler:

    def __init__(self):
        self._running = False
        self._config = KakaoTalkConfigAdapter()
        self._monitor = KakaoTalkMonitor()
        self._dedupe = KakaoTalkDeduplicator()

    def start(self) -> None:
        self._running = True
        logger.info("KakaoTalk webhook handler started")

    def stop(self) -> None:
        self._running = False
        self._dedupe.reset()
        logger.info("KakaoTalk webhook handler stopped")

    def configure(self, config: dict) -> None:
        self._config.list_account_ids(config)

    @property
    def running(self) -> bool:
        return self._running

    @property
    def config(self) -> KakaoTalkConfigAdapter:
        return self._config


_handler = KakaoTalkWebhookHandler()


@router.post("/skill")
async def kakaotalk_skill_callback(
    request: Request,
    x_kakao_admin_key: str = Header("", alias="X-Kakao-Admin-Key"),
):
    if not _handler.running:
        return PlainTextResponse("", status_code=503)

    body = await _read_body_with_limit(request)
    if body is None:
        return PlainTextResponse("", status_code=413)

    account, account_id, admin_key = await _resolve_account_for_webhook(body, x_kakao_admin_key)
    if not account:
        return PlainTextResponse("", status_code=401)

    payload = _handler._monitor.parse_webhook_body(body)
    skill_request = _handler._monitor.parse_skill_request(payload)
    if not skill_request:
        return JSONResponse(content={
            "version": "2.0",
            "template": {"outputs": [{"simpleText": {"text": "요청을 처리할 수 없습니다."}}]},
        })

    dedupe_key = build_dedupe_key(account_id, skill_request)
    if _handler._dedupe.is_duplicate(dedupe_key):
        logger.debug("KakaoTalk duplicate skill request: key=%s", dedupe_key)
        return JSONResponse(content={
            "version": "2.0",
            "template": {"outputs": [{"simpleText": {"text": ""}}]},
        })

    um = _handler._monitor.build_unified_message(skill_request, account_id)
    if um:
        asyncio.create_task(
            _dispatch_to_agent(um),
            name=f"kakaotalk-dispatch-{um.sender.id}",
        )

    return JSONResponse(content={
        "version": "2.0",
        "template": {"outputs": [{"simpleText": {"text": ""}}]},
    })


async def _resolve_account_for_webhook(body: bytes, header_admin_key: str) -> tuple[dict | None, str, str]:
    account_ids = _handler._config.list_account_ids({})
    accounts = []
    for aid in account_ids:
        try:
            acct = await _handler._config.resolve_account(aid)
            if acct:
                accounts.append(acct)
        except Exception:
            logger.exception("KakaoTalk resolve_account error for %s", aid)

    if len(accounts) == 1:
        acct = accounts[0]
        if header_admin_key and header_admin_key == acct.get("admin_key", ""):
            return acct, acct.get("account_id", "default"), acct.get("admin_key", "")
        return acct, acct.get("account_id", "default"), acct.get("admin_key", "")

    for acct in accounts:
        if header_admin_key and header_admin_key == acct.get("admin_key", ""):
            return acct, acct.get("account_id", "default"), acct.get("admin_key", "")

    env_key = os.environ.get(ENV_KAKAO_ADMIN_KEY, "")
    if env_key:
        return {
            "account_id": "default",
            "admin_key": env_key,
            "name": "default",
        }, "default", env_key

    return None, "", ""


async def _dispatch_to_agent(msg) -> None:
    try:
        from yuxi.channel.runtime.manager import gateway

        processor = getattr(gateway, "_processor", None)
        if processor is None:
            logger.warning("KakaoTalk dispatch: message processor not available")
            return

        await asyncio.wait_for(processor.process(msg), timeout=120.0)
    except TimeoutError:
        logger.error("KakaoTalk agent response timeout for user %s", msg.sender.id)
    except Exception:
        logger.exception("KakaoTalk dispatch error for user %s", msg.sender.id)


async def _read_body_with_limit(request: Request) -> bytes | None:
    try:
        body = await asyncio.wait_for(request.body(), timeout=BODY_TIMEOUT_S)
    except TimeoutError:
        logger.warning("KakaoTalk webhook: body read timeout")
        return None

    if len(body) > MAX_BODY_BYTES:
        logger.warning("KakaoTalk webhook: body too large (%d bytes)", len(body))
        return None

    return body