"""点单端老板推荐官：按推荐官 UserUID 绑定，店铺跟随。无邀请码。"""
from django.db import transaction
from django.db.models import F

from shop.models import Dianpu
from shop.services.shop_binding import (
    clear_user_shop_binding,
    get_user_shop_binding,
    set_user_shop_binding,
)
from users.models import YonghuCYaoqing
from users.business_models import User

import logging

logger = logging.getLogger(__name__)


def get_or_create_c_yaoqing(user):
    """获取或创建用户的点单端推荐关系记录。"""
    profile, _ = YonghuCYaoqing.objects.get_or_create(user=user)
    return profile


def sync_shop_from_inviter(invitee_user, inviter_user):
    """
    按推荐官店铺同步被推荐人店铺：
    - 推荐官有正常店铺 → 被推荐人绑到同一店（一人一店）
    - 推荐官无店铺 → 被推荐人解绑店铺（回落平台公共商品逻辑）
    须在 transaction.atomic 内调用。
    """
    inviter_binding = get_user_shop_binding(inviter_user)

    if inviter_binding and inviter_binding.dianpu.zhuangtai == 1:
        dianpu = Dianpu.objects.select_for_update().get(id=inviter_binding.dianpu_id)
        changed, msg = set_user_shop_binding(invitee_user, dianpu)
        return {'shop_synced': True, 'dianpu_id': dianpu.id, 'changed': changed, 'msg': msg}

    old_id = clear_user_shop_binding(invitee_user)
    return {
        'shop_synced': False,
        'dianpu_id': None,
        'changed': bool(old_id),
        'msg': '推荐官未绑定店铺，已解除店铺绑定' if old_id else '推荐官未绑定店铺',
    }


def bind_c_inviter_by_uid(invitee_user, inviter_uid):
    """
    用推荐官 UserUID 绑定/换绑，并同步店铺。
    扫码参数：yaoqingren / inviterUid（不是邀请码）。
    """
    uid = (inviter_uid or '').strip()
    if not uid:
        return {'code': 400, 'msg': '推荐官ID不能为空', 'data': None}
    if len(uid) > 20:
        return {'code': 400, 'msg': '推荐官ID格式错误', 'data': None}

    try:
        inviter = User.query.get(UserUID=uid)
    except User.DoesNotExist:
        return {'code': 404, 'msg': '推荐官不存在', 'data': None}

    if inviter.UserUID == invitee_user.UserUID:
        return {'code': 400, 'msg': '不能绑定自己为推荐官', 'data': None}

    with transaction.atomic():
        inviter_profile = get_or_create_c_yaoqing(inviter)
        invitee_profile = get_or_create_c_yaoqing(invitee_user)
        invitee_profile = YonghuCYaoqing.objects.select_for_update().get(pk=invitee_profile.pk)
        inviter_profile = YonghuCYaoqing.objects.select_for_update().get(pk=inviter_profile.pk)

        old_inviter_uid = (invitee_profile.yaoqingren or '').strip() or None
        new_inviter_uid = inviter.UserUID

        if old_inviter_uid == new_inviter_uid:
            shop_info = sync_shop_from_inviter(invitee_user, inviter)
            return {
                'code': 200,
                'msg': '已绑定该推荐官',
                'data': {
                    'yaoqingren': new_inviter_uid,
                    'rebinding': False,
                    'shop': shop_info,
                },
            }

        if old_inviter_uid:
            old_p = (
                YonghuCYaoqing.objects.select_for_update()
                .filter(user__UserUID=old_inviter_uid)
                .first()
            )
            if old_p and old_p.yaogingshuliang > 0:
                old_p.yaogingshuliang = F('yaogingshuliang') - 1
                old_p.save(update_fields=['yaogingshuliang', 'UpdateTime'])

        inviter_profile.yaogingshuliang = F('yaogingshuliang') + 1
        inviter_profile.save(update_fields=['yaogingshuliang', 'UpdateTime'])

        invitee_profile.yaoqingren = new_inviter_uid
        invitee_profile.save(update_fields=['yaoqingren', 'UpdateTime'])

        shop_info = sync_shop_from_inviter(invitee_user, inviter)

    logger.info(
        '点单端推荐官绑定: invitee=%s inviter=%s old=%s shop=%s',
        invitee_user.UserUID, new_inviter_uid, old_inviter_uid, shop_info,
    )
    return {
        'code': 200,
        'msg': '绑定成功' if not old_inviter_uid else '已换绑推荐官',
        'data': {
            'yaoqingren': new_inviter_uid,
            'rebinding': bool(old_inviter_uid),
            'shop': shop_info,
        },
    }