function isValidIPv4(address) {
  const parts = address.split(".");
  if (parts.length !== 4) return false;
  for (const part of parts) {
    if (!/^\d{1,3}$/.test(part)) return false;
    const n = Number(part);
    if (n < 0 || n > 255) return false;
    if (part.length > 1 && part.startsWith("0")) return false;
  }
  return true;
}

function isValidIPv6(address) {
  if (typeof address !== "string") return false;
  let addr = address.trim();
  if (addr.startsWith("[") && addr.endsWith("]")) addr = addr.slice(1, -1);
  const percentIndex = addr.indexOf("%");
  if (percentIndex !== -1) addr = addr.slice(0, percentIndex);
  if (addr.length === 0) return false;
  if (!/^[0-9a-fA-F:.]+$/.test(addr)) return false;

  const hasEmbeddedIPv4 = addr.includes(".");
  if (hasEmbeddedIPv4) {
    const lastColon = addr.lastIndexOf(":");
    if (lastColon === -1) return false;
    const tail = addr.slice(lastColon + 1);
    if (!isValidIPv4(tail)) return false;
    addr = `${addr.slice(0, lastColon)}:ipv4`;
  }

  const isGroup = (g) => g === "ipv4" || /^[0-9a-fA-F]{1,4}$/.test(g);
  const countGroups = (groups) =>
    groups.reduce((sum, g) => sum + (g === "ipv4" ? 2 : 1), 0);

  if (addr.includes("::")) {
    if (addr.indexOf("::") !== addr.lastIndexOf("::")) return false;
    const [left, right] = addr.split("::");
    const leftGroups = left ? left.split(":").filter(Boolean) : [];
    const rightGroups = right ? right.split(":").filter(Boolean) : [];
    if (!leftGroups.every(isGroup) || !rightGroups.every(isGroup)) return false;
    const total = countGroups(leftGroups) + countGroups(rightGroups);
    return total < 8;
  }

  const groups = addr.split(":");
  if (groups.some((g) => g.length === 0)) return false;
  if (!groups.every(isGroup)) return false;
  const total = countGroups(groups);
  return total === 8;
}

function classifyIp(address) {
  if (!address) return "unknown";
  if (isValidIPv4(address)) return "ipv4";
  if (isValidIPv6(address)) return "ipv6";
  return "unknown";
}

function getClientIp(req) {
  return (
    req.headers.get("CF-Connecting-IP") ||
    (req.headers.get("X-Forwarded-For") || "").split(",")[0].trim() ||
    ""
  );
}

const CONTINENT_ZH = {
  AF: "非洲", AN: "南极洲", AS: "亚洲", EU: "欧洲",
  NA: "北美洲", OC: "大洋洲", SA: "南美洲",
};

const COUNTRY_ZH = {
  AD: "安道尔", AE: "阿联酋", AF: "阿富汗", AG: "安提瓜和巴布达",
  AI: "安圭拉", AL: "阿尔巴尼亚", AM: "亚美尼亚", AO: "安哥拉",
  AQ: "南极洲", AR: "阿根廷", AS: "美属萨摩亚", AT: "奥地利",
  AU: "澳大利亚", AW: "阿鲁巴", AX: "奥兰群岛", AZ: "阿塞拜疆",
  BA: "波黑", BB: "巴巴多斯", BD: "孟加拉国", BE: "比利时",
  BF: "布基纳法索", BG: "保加利亚", BH: "巴林", BI: "布隆迪",
  BJ: "贝宁", BL: "圣巴泰勒米", BM: "百慕大", BN: "文莱",
  BO: "玻利维亚", BQ: "荷属加勒比", BR: "巴西", BS: "巴哈马",
  BT: "不丹", BV: "布韦岛", BW: "博茨瓦纳", BY: "白俄罗斯",
  BZ: "伯利兹", CA: "加拿大", CC: "科科斯群岛", CD: "刚果(金)",
  CF: "中非", CG: "刚果(布)", CH: "瑞士", CI: "科特迪瓦",
  CK: "库克群岛", CL: "智利", CM: "喀麦隆", CN: "中国",
  CO: "哥伦比亚", CR: "哥斯达黎加", CU: "古巴", CV: "佛得角",
  CW: "库拉索", CX: "圣诞岛", CY: "塞浦路斯", CZ: "捷克",
  DE: "德国", DJ: "吉布提", DK: "丹麦", DM: "多米尼克",
  DO: "多米尼加", DZ: "阿尔及利亚", EC: "厄瓜多尔", EE: "爱沙尼亚",
  EG: "埃及", EH: "西撒哈拉", ER: "厄立特里亚", ES: "西班牙",
  ET: "埃塞俄比亚", FI: "芬兰", FJ: "斐济", FK: "福克兰群岛",
  FM: "密克罗尼西亚", FO: "法罗群岛", FR: "法国", GA: "加蓬",
  GB: "英国", GD: "格林纳达", GE: "格鲁吉亚", GF: "法属圭亚那",
  GG: "根西岛", GH: "加纳", GI: "直布罗陀", GL: "格陵兰",
  GM: "冈比亚", GN: "几内亚", GP: "瓜德罗普", GQ: "赤道几内亚",
  GR: "希腊", GS: "南乔治亚和南桑威奇群岛", GT: "危地马拉", GU: "关岛",
  GW: "几内亚比绍", GY: "圭亚那", HK: "中国香港", HM: "赫德岛和麦克唐纳群岛",
  HN: "洪都拉斯", HR: "克罗地亚", HT: "海地", HU: "匈牙利",
  ID: "印度尼西亚", IE: "爱尔兰", IL: "以色列", IM: "马恩岛",
  IN: "印度", IO: "英属印度洋领地", IQ: "伊拉克", IR: "伊朗",
  IS: "冰岛", IT: "意大利", JE: "泽西岛", JM: "牙买加",
  JO: "约旦", JP: "日本", KE: "肯尼亚", KG: "吉尔吉斯斯坦",
  KH: "柬埔寨", KI: "基里巴斯", KM: "科摩罗", KN: "圣基茨和尼维斯",
  KP: "朝鲜", KR: "韩国", KW: "科威特", KY: "开曼群岛",
  KZ: "哈萨克斯坦", LA: "老挝", LB: "黎巴嫩", LC: "圣卢西亚",
  LI: "列支敦士登", LK: "斯里兰卡", LR: "利比里亚", LS: "莱索托",
  LT: "立陶宛", LU: "卢森堡", LV: "拉脱维亚", LY: "利比亚",
  MA: "摩洛哥", MC: "摩纳哥", MD: "摩尔多瓦", ME: "黑山",
  MF: "法属圣马丁", MG: "马达加斯加", MH: "马绍尔群岛", MK: "北马其顿",
  ML: "马里", MM: "缅甸", MN: "蒙古", MO: "中国澳门",
  MP: "北马里亚纳群岛", MQ: "马提尼克", MR: "毛里塔尼亚", MS: "蒙特塞拉特",
  MT: "马耳他", MU: "毛里求斯", MV: "马尔代夫", MW: "马拉维",
  MX: "墨西哥", MY: "马来西亚", MZ: "莫桑比克", NA: "纳米比亚",
  NC: "新喀里多尼亚", NE: "尼日尔", NF: "诺福克岛", NG: "尼日利亚",
  NI: "尼加拉瓜", NL: "荷兰", NO: "挪威", NP: "尼泊尔",
  NR: "瑙鲁", NU: "纽埃", NZ: "新西兰", OM: "阿曼",
  PA: "巴拿马", PE: "秘鲁", PF: "法属波利尼西亚", PG: "巴布亚新几内亚",
  PH: "菲律宾", PK: "巴基斯坦", PL: "波兰", PM: "圣皮埃尔和密克隆",
  PN: "皮特凯恩群岛", PR: "波多黎各", PS: "巴勒斯坦", PT: "葡萄牙",
  PW: "帕劳", PY: "巴拉圭", QA: "卡塔尔", RE: "留尼汪",
  RO: "罗马尼亚", RS: "塞尔维亚", RU: "俄罗斯", RW: "卢旺达",
  SA: "沙特阿拉伯", SB: "所罗门群岛", SC: "塞舌尔", SD: "苏丹",
  SE: "瑞典", SG: "新加坡", SH: "圣赫勒拿", SI: "斯洛文尼亚",
  SJ: "斯瓦尔巴和扬马延", SK: "斯洛伐克", SL: "塞拉利昂", SM: "圣马力诺",
  SN: "塞内加尔", SO: "索马里", SR: "苏里南", SS: "南苏丹",
  ST: "圣多美和普林西比", SV: "萨尔瓦多", SX: "荷属圣马丁", SY: "叙利亚",
  SZ: "斯威士兰", TC: "特克斯和凯科斯群岛", TD: "乍得", TF: "法属南部领地",
  TG: "多哥", TH: "泰国", TJ: "塔吉克斯坦", TK: "托克劳",
  TL: "东帝汶", TM: "土库曼斯坦", TN: "突尼斯", TO: "汤加",
  TR: "土耳其", TT: "特立尼达和多巴哥", TV: "图瓦卢", TW: "中国台湾",
  TZ: "坦桑尼亚", UA: "乌克兰", UG: "乌干达", UM: "美国本土外小岛屿",
  US: "美国", UY: "乌拉圭", UZ: "乌兹别克斯坦", VA: "梵蒂冈",
  VC: "圣文森特和格林纳丁斯", VE: "委内瑞拉", VG: "英属维尔京群岛",
  VI: "美属维尔京群岛", VN: "越南", VU: "瓦努阿图",
  WF: "瓦利斯和富图纳", WS: "萨摩亚", XK: "科索沃", YE: "也门",
  YT: "马约特", ZA: "南非", ZM: "赞比亚", ZW: "津巴布韦",
};

const CN_REGION_ZH = {
  AH: "安徽", BJ: "北京", CQ: "重庆", FJ: "福建", GD: "广东",
  GS: "甘肃", GX: "广西", GZ: "贵州", HA: "河南", HB: "湖北",
  HE: "河北", HI: "海南", HK: "香港", HL: "黑龙江", HN: "湖南",
  JL: "吉林", JS: "江苏", JX: "江西", LN: "辽宁", MO: "澳门",
  NM: "内蒙古", NX: "宁夏", QH: "青海", SC: "四川", SD: "山东",
  SH: "上海", SN: "陕西", SX: "山西", TJ: "天津", TW: "台湾",
  XJ: "新疆", XZ: "西藏", YN: "云南", ZJ: "浙江",
};

const CN_CITY_ZH = {
  "Beijing": "北京", "Shanghai": "上海", "Tianjin": "天津", "Chongqing": "重庆",
  "Shijiazhuang": "石家庄", "Tangshan": "唐山", "Qinhuangdao": "秦皇岛",
  "Handan": "邯郸", "Xingtai": "邢台", "Baoding": "保定",
  "Zhangjiakou": "张家口", "Chengde": "承德", "Cangzhou": "沧州",
  "Langfang": "廊坊", "Hengshui": "衡水",
  "Taiyuan": "太原", "Datong": "大同", "Yangquan": "阳泉",
  "Changzhi": "长治", "Jincheng": "晋城", "Shuozhou": "朔州",
  "Jinzhong": "晋中", "Yuncheng": "运城", "Xinzhou": "忻州",
  "Linfen": "临汾", "Lüliang": "吕梁", "Lvliang": "吕梁", "Luliang": "吕梁",
  "Hohhot": "呼和浩特", "Baotou": "包头", "Wuhai": "乌海",
  "Chifeng": "赤峰", "Tongliao": "通辽", "Ordos": "鄂尔多斯",
  "Hulunbuir": "呼伦贝尔", "Hulun Buir": "呼伦贝尔",
  "Bayannur": "巴彦淖尔", "Ulanqab": "乌兰察布", "Wulanchabu": "乌兰察布",
  "Hinggan": "兴安", "Xilingol": "锡林郭勒", "Xilin Gol": "锡林郭勒",
  "Alxa": "阿拉善", "Alashan": "阿拉善",
  "Shenyang": "沈阳", "Dalian": "大连", "Anshan": "鞍山",
  "Fushun": "抚顺", "Benxi": "本溪", "Dandong": "丹东",
  "Jinzhou": "锦州", "Yingkou": "营口", "Fuxin": "阜新",
  "Liaoyang": "辽阳", "Panjin": "盘锦", "Tieling": "铁岭",
  "Chaoyang": "朝阳", "Huludao": "葫芦岛",
  "Changchun": "长春", "Jilin": "吉林", "Siping": "四平",
  "Liaoyuan": "辽源", "Tonghua": "通化", "Baishan": "白山",
  "Songyuan": "松原", "Baicheng": "白城", "Yanbian": "延边",
  "Harbin": "哈尔滨", "Qiqihar": "齐齐哈尔",
  "Jixi": "鸡西", "Hegang": "鹤岗", "Shuangyashan": "双鸭山",
  "Daqing": "大庆", "Jiamusi": "佳木斯", "Qitaihe": "七台河",
  "Mudanjiang": "牡丹江", "Heihe": "黑河", "Suihua": "绥化",
  "Daxing'anling": "大兴安岭", "Daxinganling": "大兴安岭",
  "Nanjing": "南京", "Wuxi": "无锡", "Xuzhou": "徐州",
  "Changzhou": "常州", "Nantong": "南通", "Lianyungang": "连云港",
  "Huai'an": "淮安", "Huaian": "淮安", "Yancheng": "盐城",
  "Yangzhou": "扬州", "Zhenjiang": "镇江", "Suqian": "宿迁",
  "Hangzhou": "杭州", "Ningbo": "宁波", "Wenzhou": "温州",
  "Jiaxing": "嘉兴", "Huzhou": "湖州", "Shaoxing": "绍兴",
  "Jinhua": "金华", "Quzhou": "衢州", "Zhoushan": "舟山", "Lishui": "丽水",
  "Hefei": "合肥", "Wuhu": "芜湖", "Bengbu": "蚌埠",
  "Huainan": "淮南", "Ma'anshan": "马鞍山", "Maanshan": "马鞍山",
  "Huaibei": "淮北", "Tongling": "铜陵", "Anqing": "安庆",
  "Huangshan": "黄山", "Chuzhou": "滁州", "Fuyang": "阜阳",
  "Lu'an": "六安", "Luan": "六安", "Bozhou": "亳州",
  "Chizhou": "池州", "Xuancheng": "宣城",
  "Xiamen": "厦门", "Putian": "莆田", "Sanming": "三明",
  "Quanzhou": "泉州", "Zhangzhou": "漳州", "Nanping": "南平",
  "Longyan": "龙岩", "Ningde": "宁德",
  "Nanchang": "南昌", "Jingdezhen": "景德镇", "Pingxiang": "萍乡",
  "Jiujiang": "九江", "Xinyu": "新余", "Yingtan": "鹰潭",
  "Ganzhou": "赣州", "Ji'an": "吉安", "Jian": "吉安", "Shangrao": "上饶",
  "Jinan": "济南", "Qingdao": "青岛", "Zibo": "淄博",
  "Zaozhuang": "枣庄", "Dongying": "东营", "Yantai": "烟台",
  "Weifang": "潍坊", "Jining": "济宁", "Tai'an": "泰安", "Taian": "泰安",
  "Weihai": "威海", "Rizhao": "日照", "Linyi": "临沂",
  "Dezhou": "德州", "Liaocheng": "聊城", "Binzhou": "滨州", "Heze": "菏泽",
  "Zhengzhou": "郑州", "Kaifeng": "开封", "Luoyang": "洛阳",
  "Pingdingshan": "平顶山", "Anyang": "安阳", "Hebi": "鹤壁",
  "Xinxiang": "新乡", "Jiaozuo": "焦作", "Puyang": "濮阳",
  "Xuchang": "许昌", "Luohe": "漯河", "Sanmenxia": "三门峡",
  "Nanyang": "南阳", "Shangqiu": "商丘", "Xinyang": "信阳",
  "Zhoukou": "周口", "Zhumadian": "驻马店", "Jiyuan": "济源",
  "Wuhan": "武汉", "Huangshi": "黄石", "Shiyan": "十堰",
  "Yichang": "宜昌", "Xiangyang": "襄阳", "Ezhou": "鄂州",
  "Jingmen": "荆门", "Xiaogan": "孝感", "Jingzhou": "荆州",
  "Huanggang": "黄冈", "Xianning": "咸宁", "Suizhou": "随州",
  "Enshi": "恩施", "Xiantao": "仙桃", "Qianjiang": "潜江",
  "Tianmen": "天门", "Shennongjia": "神农架",
  "Changsha": "长沙", "Zhuzhou": "株洲", "Xiangtan": "湘潭",
  "Hengyang": "衡阳", "Shaoyang": "邵阳", "Yueyang": "岳阳",
  "Changde": "常德", "Zhangjiajie": "张家界", "Yiyang": "益阳",
  "Chenzhou": "郴州", "Yongzhou": "永州", "Huaihua": "怀化",
  "Loudi": "娄底", "Xiangxi": "湘西",
  "Guangzhou": "广州", "Shaoguan": "韶关", "Shenzhen": "深圳",
  "Zhuhai": "珠海", "Shantou": "汕头", "Foshan": "佛山",
  "Jiangmen": "江门", "Zhanjiang": "湛江", "Maoming": "茂名",
  "Zhaoqing": "肇庆", "Huizhou": "惠州", "Meizhou": "梅州",
  "Shanwei": "汕尾", "Heyuan": "河源", "Yangjiang": "阳江",
  "Qingyuan": "清远", "Dongguan": "东莞", "Zhongshan": "中山",
  "Chaozhou": "潮州", "Jieyang": "揭阳", "Yunfu": "云浮",
  "Nanning": "南宁", "Liuzhou": "柳州", "Guilin": "桂林",
  "Wuzhou": "梧州", "Beihai": "北海", "Fangchenggang": "防城港",
  "Qinzhou": "钦州", "Guigang": "贵港", "Baise": "百色", "Bose": "百色",
  "Hechi": "河池", "Laibin": "来宾", "Chongzuo": "崇左", "Hezhou": "贺州",
  "Haikou": "海口", "Sanya": "三亚", "Sansha": "三沙",
  "Danzhou": "儋州", "Wuzhishan": "五指山", "Wanning": "万宁",
  "Dongfang": "东方", "Qionghai": "琼海", "Wenchang": "文昌",
  "Chengdu": "成都", "Zigong": "自贡", "Panzhihua": "攀枝花",
  "Luzhou": "泸州", "Deyang": "德阳", "Mianyang": "绵阳",
  "Guangyuan": "广元", "Suining": "遂宁", "Neijiang": "内江",
  "Leshan": "乐山", "Nanchong": "南充", "Meishan": "眉山",
  "Yibin": "宜宾", "Guang'an": "广安", "Guangan": "广安",
  "Dazhou": "达州", "Ya'an": "雅安", "Yaan": "雅安",
  "Bazhong": "巴中", "Ziyang": "资阳",
  "Aba": "阿坝", "Ngawa": "阿坝", "Garze": "甘孜", "Ganzi": "甘孜",
  "Liangshan": "凉山",
  "Guiyang": "贵阳", "Liupanshui": "六盘水", "Zunyi": "遵义",
  "Anshun": "安顺", "Bijie": "毕节", "Tongren": "铜仁",
  "Qianxinan": "黔西南", "Qiandongnan": "黔东南", "Qiannan": "黔南",
  "Kunming": "昆明", "Qujing": "曲靖", "Yuxi": "玉溪",
  "Baoshan": "保山", "Zhaotong": "昭通", "Lijiang": "丽江",
  "Pu'er": "普洱", "Puer": "普洱", "Lincang": "临沧",
  "Chuxiong": "楚雄", "Honghe": "红河", "Wenshan": "文山",
  "Xishuangbanna": "西双版纳", "Dali": "大理", "Dehong": "德宏",
  "Nujiang": "怒江", "Diqing": "迪庆", "Deqen": "迪庆",
  "Lhasa": "拉萨", "Chamdo": "昌都", "Changdu": "昌都",
  "Shannan": "山南", "Lhoka": "山南",
  "Shigatse": "日喀则", "Xigaze": "日喀则",
  "Nagqu": "那曲", "Naqu": "那曲",
  "Ngari": "阿里", "Ali": "阿里",
  "Nyingchi": "林芝", "Linzhi": "林芝",
  "Xi'an": "西安", "Xian": "西安", "Tongchuan": "铜川",
  "Baoji": "宝鸡", "Xianyang": "咸阳", "Weinan": "渭南",
  "Yan'an": "延安", "Yanan": "延安", "Hanzhong": "汉中",
  "Ankang": "安康", "Shangluo": "商洛",
  "Lanzhou": "兰州", "Jiayuguan": "嘉峪关", "Jinchang": "金昌",
  "Baiyin": "白银", "Tianshui": "天水", "Wuwei": "武威",
  "Zhangye": "张掖", "Pingliang": "平凉", "Jiuquan": "酒泉",
  "Qingyang": "庆阳", "Dingxi": "定西", "Longnan": "陇南",
  "Linxia": "临夏", "Gannan": "甘南",
  "Xining": "西宁", "Haidong": "海东", "Haibei": "海北",
  "Huangnan": "黄南", "Guoluo": "果洛", "Golog": "果洛",
  "Yushu": "玉树", "Haixi": "海西",
  "Yinchuan": "银川", "Shizuishan": "石嘴山", "Wuzhong": "吴忠",
  "Guyuan": "固原", "Zhongwei": "中卫",
  "Urumqi": "乌鲁木齐", "Karamay": "克拉玛依",
  "Turpan": "吐鲁番", "Turfan": "吐鲁番",
  "Hami": "哈密", "Changji": "昌吉",
  "Bortala": "博尔塔拉", "Bole": "博乐",
  "Bayingol": "巴音郭楞", "Bayingolin": "巴音郭楞",
  "Aksu": "阿克苏", "Kizilsu": "克孜勒苏",
  "Kashgar": "喀什", "Hotan": "和田",
  "Ili": "伊犁", "Yili": "伊犁",
  "Tacheng": "塔城", "Altay": "阿勒泰",
  "Shihezi": "石河子", "Aral": "阿拉尔", "Alar": "阿拉尔",
  "Tumxuk": "图木舒克", "Tumushuke": "图木舒克",
  "Wujiaqu": "五家渠", "Beitun": "北屯",
  "Hong Kong": "香港", "Macau": "澳门", "Macao": "澳门",
  "Taipei": "台北", "New Taipei": "新北", "Kaohsiung": "高雄",
  "Taichung": "台中", "Tainan": "台南", "Hsinchu": "新竹",
  "Keelung": "基隆", "Chiayi": "嘉义", "Taoyuan": "桃园",
  "Pingtung": "屏东", "Changhua": "彰化", "Hualien": "花莲",
  "Yilan": "宜兰", "Nantou": "南投", "Miaoli": "苗栗",
  "Yunlin": "云林", "Taitung": "台东", "Penghu": "澎湖", "Kinmen": "金门",
};

const CN_CITY_DISAMBIG = {
  "Taizhou": { JS: "泰州", ZJ: "台州" },
  "Fuzhou": { FJ: "福州", JX: "抚州" },
  "Yichun": { HL: "伊春", JX: "宜春" },
  "Yulin": { GX: "玉林", SN: "榆林" },
  "Suzhou": { JS: "苏州", AH: "宿州" },
};

function getRegionName(country, region, regionCode) {
  if (country === "CN" && regionCode) return CN_REGION_ZH[regionCode] || region || "";
  return region || "";
}

function getCityName(country, city, regionCode) {
  if (country !== "CN" && country !== "HK" && country !== "MO" && country !== "TW") return city || "";
  const disambig = CN_CITY_DISAMBIG[city];
  if (disambig && regionCode && disambig[regionCode]) return disambig[regionCode];
  return CN_CITY_ZH[city] || city || "";
}

function jsonResponse(payload, reqUrl, { status = 200, headers = {} } = {}) {
  const pretty = reqUrl.searchParams.get("pretty");
  const body = pretty ? JSON.stringify(payload, null, 2) : JSON.stringify(payload);
  return new Response(body, {
    status,
    headers: {
      "Content-Type": "application/json; charset=utf-8",
      "Cache-Control": "no-store",
      ...headers,
    },
  });
}

export default {
  async fetch(request) {
    const url = new URL(request.url);
    const path = url.pathname;

    // --- CORS（给 API 路径用） ---
    const corsHeaders = {
      "Access-Control-Allow-Origin": "*",
      "Access-Control-Allow-Methods": "GET,OPTIONS",
      "Access-Control-Allow-Headers": "Content-Type",
      "Access-Control-Max-Age": "86400",
    };

    // 预检
    if (request.method === "OPTIONS") {
      return new Response(null, { status: 204, headers: corsHeaders });
    }

    // 只提供 GET
    if (request.method !== "GET") {
      return new Response("Method Not Allowed", { status: 405 });
    }

    // 取公网 IP（优先 CF-Connecting-IP）
    const ip = getClientIp(request);
    const ipVersion = classifyIp(ip);

    // Cloudflare 地理/网络信息（在边缘注入；本地 dev 可能为空）
    const cf = request.cf || {};

    const apiPayload = {
      ip,
      ipVersion,
      userAgent: request.headers.get("User-Agent") || "",
      // 常见 cf 字段（不同账号/计划/场景可用字段会有差异）
      geo: {
        country: cf.country || "",
        countryName: COUNTRY_ZH[cf.country] || cf.country || "",
        region: cf.region || "",
        regionName: getRegionName(cf.country, cf.region, cf.regionCode),
        regionCode: cf.regionCode || "",
        city: cf.city || "",
        cityName: getCityName(cf.country, cf.city, cf.regionCode),
        postalCode: cf.postalCode || "",
        timezone: cf.timezone || "",
        continent: cf.continent || "",
        continentName: CONTINENT_ZH[cf.continent] || cf.continent || "",
        latitude: cf.latitude || "",
        longitude: cf.longitude || "",
      },
      network: {
        asn: cf.asn || "",
        asOrganization: cf.asOrganization || "",
        colo: cf.colo || "",
        httpProtocol: cf.httpProtocol || "",
      },
      ts: new Date().toISOString(),
      // 如果你想“全量返回”，可把 cf 全部带回去（注意体积）
      // cf,
    };

    // API：/api
    if (path === "/api") {
      return jsonResponse(apiPayload, url, { headers: { ...corsHeaders } });
    }

    // 仅返回 IPv4：/ipv4
    if (path === "/ipv4") {
      const expected = "ipv4";
      if (!ip || ipVersion === "unknown") {
        return jsonResponse(
          {
            ok: false,
            expected,
            got: ipVersion,
            ip,
            error: "IP not found",
            ts: new Date().toISOString(),
          },
          url,
          { status: 400, headers: { ...corsHeaders } },
        );
      }
      if (ipVersion !== expected) {
        return jsonResponse(
          {
            ok: false,
            expected,
            got: ipVersion,
            ip,
            error: "Expected IPv4, but request reached Cloudflare over a non-IPv4 connection.",
            hint:
              "服务器无法强制切换 IP 协议栈；请在客户端侧使用 IPv4 访问（例如 curl -4），或检查网络/DNS 的优先级。",
            ts: new Date().toISOString(),
          },
          url,
          { status: 400, headers: { ...corsHeaders } },
        );
      }
      return jsonResponse(
        { ok: true, ip, ipVersion, ts: new Date().toISOString() },
        url,
        { headers: { ...corsHeaders } },
      );
    }

    // 仅返回 IPv6：/ipv6
    if (path === "/ipv6") {
      const expected = "ipv6";
      if (!ip || ipVersion === "unknown") {
        return jsonResponse(
          {
            ok: false,
            expected,
            got: ipVersion,
            ip,
            error: "IP not found",
            ts: new Date().toISOString(),
          },
          url,
          { status: 400, headers: { ...corsHeaders } },
        );
      }
      if (ipVersion !== expected) {
        return jsonResponse(
          {
            ok: false,
            expected,
            got: ipVersion,
            ip,
            error: "Expected IPv6, but request reached Cloudflare over IPv4.",
            hint: [
              "服务器端无法把一次 IPv4 请求“改成”IPv6；是否走 v4/v6 由客户端网络与 DNS 决定（Happy Eyeballs）。",
              `命令行可用：curl -6 ${url.origin}/ipv6`,
              "若你需要“强制 IPv6”，建议绑定一个仅 AAAA 解析的域名/子域名到本 Worker，再用该域名访问 /ipv6。",
            ],
            ts: new Date().toISOString(),
          },
          url,
          { status: 400, headers: { ...corsHeaders } },
        );
      }
      return jsonResponse(
        { ok: true, ip, ipVersion, ts: new Date().toISOString() },
        url,
        { headers: { ...corsHeaders } },
      );
    }

    // 网页：/
    if (path === "/" || path === "/index.html") {
      const html = `<!doctype html>
<html lang="zh-CN">
<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width,initial-scale=1" />
  <title>cf-ip-geo</title>
  <style>
    :root{color-scheme:light dark;}
    body{font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial;max-width:920px;margin:40px auto;padding:0 16px;line-height:1.55;}
    h1{font-size:28px;margin:0 0 8px;}
    p{margin:10px 0;}
    a{color:inherit}
    code{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:0.95em;}
    pre{background:rgba(17,24,39,.95);color:#e5e7eb;padding:14px;border-radius:12px;overflow:auto;}
    .muted{color:rgb(107,114,128);font-size:13px}
    .card{border:1px solid rgba(229,231,235,.9);border-radius:14px;padding:16px 16px;margin:16px 0;}
    ul{margin:10px 0 0 18px;padding:0}
    li{margin:6px 0}
    details{border:1px solid rgba(229,231,235,.9);border-radius:12px;padding:12px 12px;margin-top:14px;}
    summary{cursor:pointer;font-weight:600}
  </style>
</head>
<body>
  <h1>cf-ip-geo</h1>
  <p class="muted">Cloudflare Workers: 根据访问者 IP 返回地理/网络信息（数据来自 <code>request.cf</code> 与 <code>CF-Connecting-IP</code>）。</p>

  <div class="card">
    <h2>HTTP API</h2>
    <ul>
      <li><code>GET /api</code>：返回 JSON（支持 <code>?pretty=1</code>）。</li>
      <li><code>GET /ipv4</code>：返回 JSON（仅允许 IPv4 连接；否则 400）。</li>
      <li><code>GET /ipv6</code>：返回 JSON（仅允许 IPv6 连接；否则 400）。</li>
    </ul>
    <p class="muted">API 默认允许跨域（<code>Access-Control-Allow-Origin: *</code>）。</p>
    <p class="muted">提示：浏览器/系统会自动选择 IPv4/IPv6（可能优先走 IPv4）。如需强制测试 IPv6，请用 <code>curl -6</code> 或使用仅 AAAA 解析的域名访问。</p>

    <h3>Examples</h3>
    <pre><code>curl ${url.origin}/api?pretty=1
curl -4 ${url.origin}/ipv4?pretty=1
curl -6 ${url.origin}/ipv6?pretty=1</code></pre>
  </div>

  <details>
    <summary>Live: GET /api?pretty=1</summary>
    <pre id="out">Loading…</pre>
  </details>

  <script>
    async function run(){
      const out = document.getElementById('out');
      out.textContent = 'Loading…';
      try{
        const r = await fetch('/api?pretty=1', { cache: 'no-store' });
        const t = await r.text();
        out.textContent = t;
      }catch(e){
        out.textContent = 'Failed: ' + (e && e.message ? e.message : String(e));
      }
    }
    run();
  </script>
</body>
</html>`;
      return new Response(html, {
        headers: {
          "Content-Type": "text/html; charset=utf-8",
          "Cache-Control": "no-store",
        },
      });
    }

    // 其他路径：404
    return new Response("Not Found", { status: 404 });
  },
};