using System;
using System.Collections.Generic;
using System.Globalization;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;
using System.Web.Script.Serialization;

namespace AyueSdk
{
    /// <summary>
    /// 阿越云验证 - C# SDK
    ///
    /// 支持：卡密登录、心跳保活、公告获取、版本检查（含强制更新）、
    ///       卡密解绑、获取应用配置、获取外链文件、应用账号登录
    ///
    /// 环境：.NET Framework 4.5+ / .NET Core 3.1+ / .NET 5+
    /// 依赖：System.Web.Extensions（.NET Framework）或 System.Text.Json（.NET Core，见注释）
    ///
    /// @version 1.0.0
    /// </summary>
    public class AyueVerify
    {
        private readonly string _baseUrl;
        private readonly int _appId;
        private readonly string _appKey;
        private readonly string _rc4Key;
        private readonly int _miType;
        private readonly int _miTime;
        private readonly bool _signEnabled;
        private readonly int _timeoutMs;

        public string LastError { get; private set; } = "";
        public int LastCode { get; private set; } = 0;

        /// <summary>
        /// 初始化
        /// </summary>
        /// <param name="baseUrl">验证服务器地址，如 https://yz.example.com</param>
        /// <param name="appId">应用 ID</param>
        /// <param name="appKey">应用密钥</param>
        /// <param name="rc4Key">通信密钥</param>
        /// <param name="miType">加密类型 0=明文 1=RC4 2=Base64</param>
        /// <param name="sign">是否签名</param>
        /// <param name="timeoutMs">超时毫秒</param>
        public AyueVerify(string baseUrl, int appId, string appKey = "", string rc4Key = "",
                          int miType = 0, bool sign = false, int timeoutMs = 10000, int miTime = 10)
        {
            _baseUrl = (baseUrl ?? "").TrimEnd('/') + "/";
            _appId = appId;
            _appKey = appKey ?? "";
            _rc4Key = rc4Key ?? "";
            _miType = miType;
            _miTime = miTime;
            _signEnabled = sign;
            _timeoutMs = timeoutMs > 0 ? timeoutMs : 10000;
        }

        // ==================== 业务接口 ====================

        /// <summary>卡密登录</summary>
        public Result Login(string kami, string markcode)
        {
            var p = new Dictionary<string, string> { { "kami", kami }, { "markcode", markcode } };
            return Normalize(Request("kmlogon", p), true);
        }

        /// <summary>心跳保活</summary>
        public Result Heartbeat(string kami, string markcode)
        {
            var p = new Dictionary<string, string> { { "kami", kami }, { "markcode", markcode } };
            return Normalize(Request("heartbeat", p), true);
        }

        /// <summary>退出心跳</summary>
        public Result HeartbeatQuit(string kami) => Heartbeat(kami, "quit");

        /// <summary>获取公告</summary>
        public string Notice()
        {
            var r = Request("notice", new Dictionary<string, string>());
            if (CodeOf(r) == 200 && r.ContainsKey("msg") && r["msg"] is Dictionary<string, object> d)
            {
                return d.ContainsKey("app_gg") && d["app_gg"] != null ? d["app_gg"].ToString() : "";
            }
            return "";
        }

        /// <summary>获取应用配置</summary>
        public Config GetConfig(bool withPay = false)
        {
            var p = new Dictionary<string, string>();
            if (withPay) p["pay"] = "1";

            var r = Request("ini", p);
            var c = new Config { Ok = CodeOf(r) == 200, Code = LastCode };
            if (c.Ok && r.ContainsKey("msg") && r["msg"] is Dictionary<string, object> d)
            {
                c.Version = Str(d, "version");
                c.VersionInfo = Str(d, "version_info");
                c.UpdateUrl = Str(d, "app_update_url");
                c.UpdateShow = Str(d, "app_update_show");
                c.MustUpdate = Str(d, "app_update_must") == "y";
            }
            else
            {
                c.Msg = LastError;
            }
            return c;
        }

        /// <summary>检查更新</summary>
        public UpdateInfo CheckUpdate(string currentVersion)
        {
            var cfg = GetConfig();
            var u = new UpdateInfo();
            if (!cfg.Ok) { u.Msg = cfg.Msg; return u; }

            u.Ok = true;
            u.HasUpdate = VersionCompare(cfg.Version, currentVersion) > 0;
            u.MustUpdate = u.HasUpdate && cfg.MustUpdate;
            u.Latest = cfg.Version;
            u.Url = cfg.UpdateUrl;
            u.Desc = string.IsNullOrEmpty(cfg.UpdateShow) ? cfg.VersionInfo : cfg.UpdateShow;
            return u;
        }

        /// <summary>卡密解绑</summary>
        public Result Unbind(string kami, string markcode)
        {
            var p = new Dictionary<string, string> { { "kami", kami }, { "markcode", markcode } };
            return Normalize(Request("kmunmachine", p), false);
        }

        /// <summary>获取外链文件（原始 JSON）</summary>
        public string GetFilesRaw()
        {
            return RequestRaw("getfile", new Dictionary<string, string>());
        }

        /// <summary>应用账号登录</summary>
        public Result UserLogin(string user, string password)
        {
            var p = new Dictionary<string, string> { { "user", user }, { "password", password } };
            return Normalize(Request("userlogon", p), false);
        }

        /// <summary>应用账号注册</summary>
        public Result UserRegister(string user, string password)
        {
            var p = new Dictionary<string, string> { { "user", user }, { "password", password } };
            return Normalize(Request("userreg", p), false);
        }

        /// <summary>应用账号心跳</summary>
        public Result UserHeartbeat(string user, string markcode)
        {
            var p = new Dictionary<string, string> { { "user", user }, { "markcode", markcode } };
            return Normalize(Request("userheartbeat", p), false);
        }

        // ==================== 底层通信 ====================

        private string RequestRaw(string api, Dictionary<string, string> fields)
        {
            LastError = "";
            LastCode = 0;

            string value = RandomStr(16);
            fields["value"] = value;

            // 关键：服务端 mi_time > 0 时强制要求 t 参数，缺失返回 108
            if (_miTime > 0 && !fields.ContainsKey("t"))
            {
                fields["t"] = DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString();
            }

            string url = _baseUrl + "api.php?api=" + Uri.EscapeDataString(api) + "&app=" + _appId;

            var post = new Dictionary<string, string>();
            if (_miType == 0)
            {
                foreach (var kv in fields) post[kv.Key] = kv.Value;
            }
            else
            {
                string plain = BuildQuery(fields);
                post["data"] = Encrypt(plain);
                post["value"] = value;
            }

            if (_signEnabled)
            {
                var src = new Dictionary<string, string>(fields);
                if (_miType != 0) src["data"] = post["data"];
                post["sign"] = MakeSign(src);
            }

            var sb = new StringBuilder();
            foreach (var kv in post)
            {
                if (sb.Length > 0) sb.Append('&');
                sb.Append(Uri.EscapeDataString(kv.Key)).Append('=').Append(Uri.EscapeDataString(kv.Value ?? ""));
            }
            byte[] body = Encoding.UTF8.GetBytes(sb.ToString());

            try
            {
                ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
                var req = (HttpWebRequest)WebRequest.Create(url);
                req.Method = "POST";
                req.ContentType = "application/x-www-form-urlencoded";
                req.UserAgent = "AyueVerify-CSharp-SDK/1.0.0";
                req.Timeout = _timeoutMs;
                req.ReadWriteTimeout = _timeoutMs;
                req.ContentLength = body.Length;

                using (var s = req.GetRequestStream()) s.Write(body, 0, body.Length);
                using (var resp = (HttpWebResponse)req.GetResponse())
                using (var rs = resp.GetResponseStream())
                using (var reader = new System.IO.StreamReader(rs, Encoding.UTF8))
                {
                    return reader.ReadToEnd();
                }
            }
            catch (Exception ex)
            {
                LastError = "网络请求失败: " + ex.Message;
                LastCode = -1;
                return "{\"code\":-1,\"msg\":\"网络请求失败\"}";
            }
        }

        private Dictionary<string, object> Request(string api, Dictionary<string, string> fields)
        {
            string raw = RequestRaw(api, fields);
            try
            {
                var ser = new JavaScriptSerializer();
                // 去除 UTF-8 BOM
                raw = raw?.TrimStart('\uFEFF')?.Trim() ?? "";
                var obj = ser.Deserialize<Dictionary<string, object>>(raw);
                if (obj == null) throw new Exception("empty");
                LastCode = CodeOf(obj);
                if (LastCode != 200 && obj.ContainsKey("msg"))
                {
                    LastError = obj["msg"] == null ? "" : obj["msg"].ToString();
                }
                return obj;
            }
            catch (Exception e)
            {
                LastError = "返回格式错误: " + (raw.Length > 120 ? raw.Substring(0, 120) : raw);
                LastCode = -1;
                return new Dictionary<string, object> { { "code", -1 }, { "msg", LastError } };
            }
        }

        private Result Normalize(Dictionary<string, object> r, bool wantExpires)
        {
            var res = new Result
            {
                Code = CodeOf(r),
                Msg = r.ContainsKey("msg") && r["msg"] != null ? r["msg"].ToString() : ""
            };
            res.Ok = res.Code == 200;
            if (r.ContainsKey("msg") && r["msg"] is Dictionary<string, object> d)
            {
                res.Data = d;
                if (wantExpires && res.Ok && d.ContainsKey("expires_ts") && d["expires_ts"] != null)
                {
                    long.TryParse(d["expires_ts"].ToString(), out long ts);
                    res.ExpiresTs = ts;
                }
            }
            return res;
        }

        private static int CodeOf(Dictionary<string, object> r)
        {
            if (r == null || !r.ContainsKey("code") || r["code"] == null) return -1;
            return int.TryParse(r["code"].ToString(), out int c) ? c : -1;
        }

        private static string Str(Dictionary<string, object> d, string key)
        {
            return d.ContainsKey(key) && d[key] != null ? d[key].ToString() : "";
        }

        private string BuildQuery(Dictionary<string, string> f)
        {
            var sb = new StringBuilder();
            foreach (var kv in f)
            {
                if (sb.Length > 0) sb.Append('&');
                sb.Append(kv.Key).Append('=').Append(kv.Value);
            }
            return sb.ToString();
        }

        private string MakeSign(Dictionary<string, string> fields)
        {
            var ignore = new HashSet<string> { "sign", "app", "api", "value",
                                               "PHPSESSID", "sec_defend", "sidenav-state" };
            var sb = new StringBuilder();
            foreach (var kv in fields)
            {
                if (ignore.Contains(kv.Key)) continue;
                sb.Append(kv.Key).Append('=').Append(kv.Value).Append('&');
            }
            sb.Append(_appKey);
            return Md5(sb.ToString());
        }

        private string Encrypt(string plain)
        {
            if (_miType == 1)
            {
                // 关键：服务端 mi_rc4 会先做 UTF-8 -> GBK 转换，客户端必须保持一致。
                string d = plain, k = _rc4Key;
                try
                {
                    var gbk = Encoding.GetEncoding("GBK");
                    d = Encoding.GetEncoding("ISO-8859-1").GetString(gbk.GetBytes(plain));
                    k = Encoding.GetEncoding("ISO-8859-1").GetString(gbk.GetBytes(_rc4Key));
                }
                catch (Exception)
                {
                    // 目标框架未注册 GBK 时（.NET Core 需注册 CodePagesEncodingProvider）
                    // 退化为原串，含中文参数可能与服务端不一致
                }
                return Rc4Hex(d, k);
            }
            return Convert.ToBase64String(Encoding.UTF8.GetBytes(plain));
        }

        private static string Rc4Hex(string data, string key)
        {
            if (string.IsNullOrEmpty(key)) return "";
            var s = new int[256];
            for (int i = 0; i < 256; i++) s[i] = i;
            int j = 0, kl = key.Length;
            for (int i = 0; i < 256; i++)
            {
                j = (j + s[i] + key[i % kl]) % 256;
                int t = s[i]; s[i] = s[j]; s[j] = t;
            }
            int x = 0, y = 0;
            var sb = new StringBuilder();
            foreach (char ch in data)
            {
                x = (x + 1) % 256;
                y = (y + s[x]) % 256;
                int t = s[x]; s[x] = s[y]; s[y] = t;
                int c = (ch ^ s[(s[x] + s[y]) % 256]) & 0xFF;
                sb.Append(c.ToString("x2"));
            }
            return sb.ToString();
        }

        private static string Md5(string s)
        {
            using (var md5 = MD5.Create())
            {
                byte[] d = md5.ComputeHash(Encoding.UTF8.GetBytes(s));
                var sb = new StringBuilder();
                foreach (byte b in d) sb.Append(b.ToString("x2"));
                return sb.ToString();
            }
        }

        private static string RandomStr(int n)
        {
            const string chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            var rnd = new Random(Guid.NewGuid().GetHashCode());
            var sb = new StringBuilder();
            for (int i = 0; i < n; i++) sb.Append(chars[rnd.Next(chars.Length)]);
            return sb.ToString();
        }

        /// <summary>版本比较：v1 &gt; v2 返回 1</summary>
        public static int VersionCompare(string v1, string v2)
        {
            var a = (v1 ?? "").Trim().Split(new[] { '.', '-', '+' });
            var b = (v2 ?? "").Trim().Split(new[] { '.', '-', '+' });
            int n = Math.Max(a.Length, b.Length);
            for (int i = 0; i < n; i++)
            {
                string x = i < a.Length ? a[i] : "0";
                string y = i < b.Length ? b[i] : "0";
                if (int.TryParse(x, out int xi) && int.TryParse(y, out int yi))
                {
                    if (xi > yi) return 1;
                    if (xi < yi) return -1;
                }
                else
                {
                    int c = string.CompareOrdinal(x, y);
                    if (c > 0) return 1;
                    if (c < 0) return -1;
                }
            }
            return 0;
        }

        /// <summary>生成设备码（首次运行应持久化）</summary>
        public static string GenerateMarkcode()
        {
            string seed = Environment.MachineName + "|" + Environment.OSVersion +
                          "|" + Environment.ProcessorCount + "|" + Environment.UserName;
            return Md5(seed).Substring(0, 24).ToUpperInvariant();
        }

        // ==================== 数据结构 ====================

        public class Result
        {
            public bool Ok;
            public int Code;
            public string Msg = "";
            public Dictionary<string, object> Data;
            public long ExpiresTs;
        }

        public class Config
        {
            public bool Ok;
            public int Code;
            public string Msg = "";
            public string Version = "";
            public string VersionInfo = "";
            public string UpdateUrl = "";
            public string UpdateShow = "";
            public bool MustUpdate;
        }

        public class UpdateInfo
        {
            public bool Ok;
            public bool HasUpdate;
            public bool MustUpdate;
            public string Latest = "";
            public string Url = "";
            public string Desc = "";
            public string Msg = "";
        }
    }
}