"""IP 归属地解析 — 阿里云市场在线 API + ip2region 离线库 + 熔断降级。"""

import ipaddress
import logging
import re
import time

import requests
from django.conf import settings

logger = logging.getLogger(__name__)

# ── 熔断状态 ──
_circuit_open_until = 0  # 在线 API 失败后，此时间戳之前直接走离线
_CIRCUIT_COOLDOWN = 60   # 熔断冷却 60 秒

# ── ip2region 搜索器缓存 ──
_ip2region_searcher = None


def _is_private_ip(ip: str) -> bool:
    """判断是否为私有/本地 IP。"""
    try:
        addr = ipaddress.ip_address(ip)
        return addr.is_private or addr.is_loopback or addr.is_reserved
    except (ValueError, TypeError):
        return True


def _normalize_city(name: str) -> str:
    """标准化城市名：去掉「市」后缀。"""
    if name and name.endswith('市'):
        return name[:-1]
    return name


def _normalize_province(name: str) -> str:
    """标准化省份名：去掉「省」「自治区」「壮族自治区」等后缀。"""
    if not name:
        return name
    for suffix in ['壮族自治区', '回族自治区', '维吾尔自治区', '自治区', '省']:
        if name.endswith(suffix):
            return name[:-len(suffix)]
    return name


def _resolve_online(ip: str) -> tuple:
    """阿里云市场 IP138 归属地 API（超时 2s）。

    Returns: (country, province, city) or raises Exception.
    """
    appcode = settings.ALIYUN_IP_GEO_APPCODE
    if not appcode:
        raise RuntimeError('ALIYUN_IP_GEO_APPCODE not configured')

    url = f'https://ali.ip138.com/ip/?ip={ip}&datatype=json'
    headers = {'Authorization': f'APPCODE {appcode}'}
    resp = requests.get(url, headers=headers, timeout=2)
    resp.raise_for_status()
    data = resp.json()

    if data.get('ret') != 'ok':
        raise RuntimeError(f'IP138 API error: {data.get("msg", data)}')

    # data.data = ["国家", "省份", "城市", "运营商", "邮编", "区号"]
    parts = data.get('data', [])
    country = parts[0] if len(parts) > 0 else ''
    province = _normalize_province(parts[1] if len(parts) > 1 else '')
    city = _normalize_city(parts[2] if len(parts) > 2 else '')

    return country, province, city


def _resolve_offline(ip: str) -> tuple:
    """ip2region 离线库解析。

    Returns: (country, province, city) or ('', '', '').
    """
    global _ip2region_searcher

    if _ip2region_searcher is None:
        try:
            import ipregion, os
            from ipregion import XdbSearcher
            pkg_dir = os.path.dirname(ipregion.__file__)
            db_path = os.path.join(pkg_dir, 'ip2region.xdb')
            content = XdbSearcher.loadContentFromFile(dbfile=db_path)
            _ip2region_searcher = XdbSearcher(contentBuff=content)
        except Exception as e:
            logger.warning('ip2region init failed: %s', e)
            return '', '', ''

    try:
        region_str = _ip2region_searcher.searchByIPStr(ip)
        # 格式: "中国|0|广东省|广州市|电信"
        parts = region_str.split('|') if region_str else []
        country = parts[0] if len(parts) > 0 and parts[0] != '0' else ''
        province = _normalize_province(parts[2] if len(parts) > 2 and parts[2] != '0' else '')
        city = _normalize_city(parts[3] if len(parts) > 3 and parts[3] != '0' else '')
        return country, province, city
    except Exception as e:
        logger.warning('ip2region lookup failed for %s: %s', ip, e)
        return '', '', ''


def resolve_ip_location(ip: str) -> tuple:
    """解析 IP 归属地。

    Returns: (country, province, city, source)
        source: 'online' / 'offline' / 'skip' / 'failed'
    """
    if not ip or _is_private_ip(ip):
        return '', '', '', 'skip'

    global _circuit_open_until

    # 尝试在线 API（熔断期间跳过）
    now = time.time()
    if now >= _circuit_open_until and settings.ALIYUN_IP_GEO_APPCODE:
        try:
            country, province, city = _resolve_online(ip)
            return country, province, city, 'online'
        except Exception as e:
            logger.warning('Online IP geo failed for %s: %s — circuit open for %ds', ip, e, _CIRCUIT_COOLDOWN)
            _circuit_open_until = now + _CIRCUIT_COOLDOWN

    # 降级到离线库
    try:
        country, province, city = _resolve_offline(ip)
        if country or province or city:
            return country, province, city, 'offline'
    except Exception as e:
        logger.warning('Offline IP geo failed for %s: %s', ip, e)

    return '', '', '', 'failed'