"""美团 CPS 券列表 + 换链。

不需要登录，客户端传经纬度即可。
"""
from __future__ import annotations

import logging
from concurrent.futures import ThreadPoolExecutor, as_completed

from fastapi import APIRouter, HTTPException

from app.core.config import settings
from app.integrations.meituan import MeituanCpsError, get_referral_link, query_coupon
from app.schemas.meituan import (
    CouponCard,
    CouponListRequest,
    CouponListResponse,
    FeedRequest,
    FeedResponse,
    ReferralLinkRequest,
    ReferralLinkResponse,
)

logger = logging.getLogger("shagua.meituan")

router = APIRouter(prefix="/api/v1/meituan", tags=["meituan-cps"])


@router.post("/coupons", response_model=CouponListResponse, summary="券列表(为您推荐)")
def list_coupons(req: CouponListRequest) -> CouponListResponse:
    if not settings.mt_cps_configured:
        return CouponListResponse(items=[], has_next=False, search_id=None)
    logger.info("[coupons] lon=%.6f lat=%.6f topic=%s", req.longitude, req.latitude, req.list_topic_id)
    try:
        raw = query_coupon(
            longitude=req.longitude,
            latitude=req.latitude,
            platform=req.platform,
            biz_line=req.biz_line,
            list_topic_id=req.list_topic_id,
            search_text=req.keyword,
            search_id=req.search_id,
            sort_field=req.sort_field,
            page_no=req.page,
            page_size=req.page_size,
        )
    except MeituanCpsError as e:
        logger.error("query_coupon failed: %s", e)
        raise HTTPException(status_code=502, detail=f"meituan: {e}") from e

    items = [CouponCard.from_raw(it) for it in (raw.get("data") or [])]
    return CouponListResponse(
        items=items,
        has_next=raw.get("hasNext", False),
        search_id=raw.get("searchId"),
    )


_TOPIC_ROUNDS = [
    (3, 3),   # 爆款筛选
    (2, 2),   # 今日必推
    (1, 5),   # 精选 + 限时筛选
]

def _interleave(waimai: list[dict], daodian: list[dict]) -> list[CouponCard]:
    items: list[CouponCard] = []
    seen: set[str] = set()
    i = j = 0
    while i < len(waimai) or j < len(daodian):
        for _ in range(2):
            if i < len(waimai):
                card = CouponCard.from_raw(waimai[i]); i += 1
                if card.product_view_sign not in seen:
                    seen.add(card.product_view_sign); items.append(card)
        if j < len(daodian):
            card = CouponCard.from_raw(daodian[j]); j += 1
            if card.product_view_sign not in seen:
                seen.add(card.product_view_sign); items.append(card)
    return items


@router.post("/feed", response_model=FeedResponse, summary="混合feed(外卖+到店交叉, 无限流)")
def feed(req: FeedRequest) -> FeedResponse:
    if not settings.mt_cps_configured:
        return FeedResponse(items=[], has_next=False, page=req.page)
    page_idx = req.page - 1
    lon, lat = req.longitude, req.latitude
    logger.info("[feed] page=%s lon=%.6f lat=%.6f", req.page, lon, lat)

    def _fetch_topic(platform: int, biz_line: int | None, topic: int) -> list[dict]:
        try:
            return (query_coupon(
                longitude=lon, latitude=lat,
                platform=platform, biz_line=biz_line,
                list_topic_id=topic, page_size=20,
            ).get("data") or [])
        except MeituanCpsError:
            return []

    if page_idx >= len(_TOPIC_ROUNDS):
        return FeedResponse(items=[], has_next=False, page=req.page)

    wm_topic, dd_topic = _TOPIC_ROUNDS[page_idx]
    with ThreadPoolExecutor(max_workers=2) as pool:
        f_wm = pool.submit(_fetch_topic, 1, None, wm_topic)
        f_dd = pool.submit(_fetch_topic, 2, 1, dd_topic)
        waimai, daodian = f_wm.result(), f_dd.result()

    items = _interleave(waimai, daodian)
    has_next = page_idx + 1 < len(_TOPIC_ROUNDS)
    return FeedResponse(items=items, has_next=has_next, page=req.page)


@router.post("/referral-link", response_model=ReferralLinkResponse, summary="换取推广链接(点抢时调)")
def referral_link(req: ReferralLinkRequest) -> ReferralLinkResponse:
    if not settings.mt_cps_configured:
        return ReferralLinkResponse(link="", link_map={})
    try:
        raw = get_referral_link(
            product_view_sign=req.product_view_sign,
            platform=req.platform,
            biz_line=req.biz_line,
            sid=req.sid,
            link_type_list=req.link_type_list,
        )
    except MeituanCpsError as e:
        logger.error("get_referral_link failed: %s", e)
        raise HTTPException(status_code=502, detail=f"meituan: {e}") from e

    link_map = raw.get("referralLinkMap") or {}
    link = raw.get("data") or link_map.get("1") or link_map.get("3") or next(iter(link_map.values()), "")
    return ReferralLinkResponse(link=link, link_map=link_map)