import asyncio
import json
import logging
import time
from urllib.parse import parse_qs

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

from yuxi.channel.extensions.farcaster.defaults import (
    WEBHOOK_BODY_MAX_BYTES,
    WEBHOOK_BODY_TIMEOUT_S,
)
from yuxi.channel.extensions.farcaster.monitor import FarcasterMonitor

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

logger = logging.getLogger(__name__)

_GATEWAY_STATE: dict = {}


def register_gateway_state(account_id: str, ctx, gateway, dedupe) -> None:
    handle = gateway.get_handle(account_id)
    bot_fid = handle.get("bot_fid", 0) if handle else 0
    bot_fname = handle.get("bot_fname", "") if handle else ""

    monitor = FarcasterMonitor(bot_fid=bot_fid, bot_fname=bot_fname)
    _GATEWAY_STATE[account_id] = {
        "ctx": ctx,
        "gateway": gateway,
        "monitor": monitor,
        "dedupe": dedupe,
    }


def unregister_gateway_state(account_id: str) -> None:
    _GATEWAY_STATE.pop(account_id, None)


async def _dispatch_webhook_event(request: Request, account_id: str = "default") -> PlainTextResponse:
    body = await _read_body(request)
    if body is None:
        return PlainTextResponse("", status_code=413)

    x_neynar_signature = request.headers.get("X-Neynar-Signature", "")

    state = _GATEWAY_STATE.get(account_id)
    if state is None:
        logger.warning("Farcaster webhook: no active gateway state for account=%s", account_id)
        return PlainTextResponse("", status_code=503)

    gateway = state["gateway"]
    handle = gateway.get_handle(account_id)
    if handle is None or not handle.get("running", False):
        return PlainTextResponse("", status_code=503)

    client = handle.get("client")
    if x_neynar_signature and client:
        if not client.verify_webhook_signature(body, x_neynar_signature):
            logger.warning("Farcaster webhook: invalid signature")
            return PlainTextResponse("", status_code=401)

    handle["last_webhook_event_at"] = time.time()

    try:
        payload = json.loads(body)
    except json.JSONDecodeError:
        logger.warning("Farcaster webhook: invalid JSON body")
        return PlainTextResponse("", status_code=400)

    event_type = payload.get("type", "")
    event_data = payload.get("data", {})

    ctx = state["ctx"]
    monitor = state["monitor"]
    dedupe = state["dedupe"]

    if event_type == "cast.created":
        await _handle_cast_event(ctx, event_data, handle, monitor, dedupe, account_id)
    elif event_type == "reaction.created":
        unified = monitor.convert_reaction_to_unified(event_data, account_id=account_id)
        if unified is not None and not dedupe.is_duplicate(unified.msg_id):
            queue = getattr(ctx, "queue", None)
            if queue is not None:
                try:
                    queue.put_nowait(unified)
                except asyncio.QueueFull:
                    logger.warning("Farcaster queue full, dropping reaction: %s", unified.msg_id)
    else:
        logger.debug("Farcaster unhandled event type: %s", event_type)

    return PlainTextResponse("ok")


@router.post("")
async def farcaster_webhook(
    request: Request,
    x_neynar_signature: str = Header("", alias="X-Neynar-Signature"),
):
    account_id = "default"
    parsed = parse_qs(str(request.url.query))
    if "account_id" in parsed:
        account_id = parsed["account_id"][0]

    return await _dispatch_webhook_event(request, account_id)


async def _handle_cast_event(
    ctx, cast_data: dict, handle: dict, monitor: FarcasterMonitor, dedupe, account_id: str = "default"
) -> None:
    text = cast_data.get("text", "")
    author = cast_data.get("author", {})
    bot_fname = handle.get("bot_fname", "")
    bot_fid = handle.get("bot_fid", 0)

    if not _check_mention(text, bot_fname, bot_fid):
        logger.debug(
            "Farcaster cast: not mentioned, fid=%s text=%.100s",
            author.get("fid", "?"),
            text,
        )
        return

    unified = monitor.convert_cast_to_unified(cast_data, account_id=account_id)
    if unified is None:
        return

    if dedupe.is_duplicate(unified.msg_id):
        return

    queue = getattr(ctx, "queue", None)
    if queue is not None:
        try:
            queue.put_nowait(unified)
        except asyncio.QueueFull:
            logger.warning("Farcaster queue full, dropping message: %s", unified.msg_id)


def _check_mention(text: str, bot_fname: str, bot_fid: int) -> bool:
    if not bot_fname:
        return False
    return f"@{bot_fname}" in text or f"@fid:{bot_fid}" in text


async def _read_body(request: Request) -> bytes | None:
    try:
        body = await asyncio.wait_for(request.body(), timeout=WEBHOOK_BODY_TIMEOUT_S)
    except TimeoutError:
        logger.warning("Farcaster webhook: body read timeout")
        return None
    if len(body) > WEBHOOK_BODY_MAX_BYTES:
        logger.warning("Farcaster webhook: body too large (%d bytes)", len(body))
        return None
    return body