using System.Net.Sockets;
using System.Net.Http;
using log4net;
using log4net.Config;
using System.Net;
using System.Data.SQLite;
using chatserver.Data;
using System.Text.Json;
using System.Reflection;

[assembly: XmlConfigurator(ConfigFile = "config/log4net.config", Watch = true)]
namespace chatserver
{
    internal class ChatServer
    {
        private static readonly ILog log = LogManager.GetLogger(typeof(ChatServer));
        private static List<Socket> Client = new();
        private static List<string> token = new();
        private static Socket? Server;
        private static SQLiteConnection? User_db;

        static void Main(string[] args)
        {
            //XmlConfigurator.Configure();
            log.Info("Hello World!");
            Server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            Server.Bind(new IPEndPoint(IPAddress.Any, 52006));
            Server.Listen(20);
            OpenUser_db();
            log.Info("服务器以在52006端口监听");
            while (true)
            {
                try
                {
                    Socket client = Server.Accept();
                    Client.Add(client);
                    log.Info($"用户{client.RemoteEndPoint}连接");
                    Thread thread = new Thread(() => HandleClient(client));
                    thread.Start();
                }
                catch (Exception ex)
                {
                    log.Error("Error accepting client connection: " + ex.Message);
                }
            }
        }
        public static void OpenUser_db()
        {
            log.Info("正在打开数据库连接...");
            User_db = new SQLiteConnection("Data Source=ServerUser.db;Version=3;"); //没有数据库则自动创建  
            User_db.Open();
            EnsureUsersTableExists(); // 确保users表存在
            log.Info("数据库连接已打开");
        }
        static void HandleClient(Socket socket)
        {
            try
            {
                while (true)
                
                {
                    byte[] buffer = new byte[1024];
                    int received = socket.Receive(buffer);
                    if (received == 0) break; // 客户端断开连接  
                    string message = System.Text.Encoding.UTF8.GetString(buffer, 0, received);
                    log.Info("Received message: " + message);
                    var Type = JsonSerializer.Deserialize<TypeData>(message);
                    if (Type != null)
                    {
                        if (Type.type == "register")
                        {
                            var sginuser = JsonSerializer.Deserialize<SignData>(message);
                            if (sginuser != null && sginuser.username != null && sginuser.password != null)
                            {
                                log.Info($"用户 {sginuser.username} 正在注册");
                                if (string.IsNullOrEmpty(sginuser.username) || string.IsNullOrEmpty(sginuser.password))
                                {
                                    log.Warn("用户名或密码不能为空");
                                    var emptyResult = new SignResultData { type = "register", status = "error_-1", message = "用户名或密码不能为空" };
                                    socket.Send(JsonSerializer.SerializeToUtf8Bytes(emptyResult));
                                    continue; // 如果用户名或密码为空，则跳过注册流程
                                }
                                if (sginuser.username.Length < 2 || sginuser.username.Length > 20)
                                {
                                    log.Warn($"用户注册时 {sginuser.username} 用户名长度不符合要求");
                                    var lengthResult = new SignResultData { type = "register", status = "error_2", message = "用户名长度必须在2到20个字符之间" };
                                    socket.Send(JsonSerializer.SerializeToUtf8Bytes(lengthResult));
                                    continue; // 如果用户名长度不符合要求，则跳过注册流程
                                }
                                if (sginuser.password.Length < 4 || sginuser.password.Length > 20)
                                {
                                    log.Warn($"用户注册时 {sginuser.username} 密码长度不符合要求");
                                    var weakPwdResult = new SignResultData { type = "register", status = "error_1", message = "密码长度必须在4到20个字符之间" };
                                    socket.Send(JsonSerializer.SerializeToUtf8Bytes(weakPwdResult));
                                    continue; // 如果密码过弱，则跳过注册流程
                                }
                                if (UserExists(sginuser.username))
                                {
                                    log.Warn($"用户 {sginuser.username} 已存在");
                                    var Result = new SignResultData { type = "register", status = "error_0", message = "用户名已存在" };
                                    socket.Send(System.Text.Encoding.UTF8.GetBytes(JsonSerializer.Serialize(Result)));
                                    continue;// 如果用户名已存在，则跳过注册流程
                                }
                                var cmd = new SQLiteCommand("INSERT INTO users (userid, username, password) VALUES (@userid, @username, @password)", User_db);
                                var timedUlid = Ulid.NewUlid(DateTimeOffset.UtcNow);
                                cmd.Parameters.AddWithValue("@userid", timedUlid);
                                cmd.Parameters.AddWithValue("@username", sginuser.username);
                                cmd.Parameters.AddWithValue("@password", sginuser.password);
                                cmd.ExecuteNonQuery();
                                log.Info($"用户 {sginuser.username} 注册成功(id:{timedUlid})");
                                var result = new SignResultData { type = "register", status = "succeed", message = "注册成功" };
                                socket.Send(System.Text.Encoding.UTF8.GetBytes(JsonSerializer.Serialize(result)));
                            }
                        }
                        else if (Type.type == "login")
                        {
                            var loginData = JsonSerializer.Deserialize<LoginData>(message);
                            if (loginData != null)
                            {
                                if (string.IsNullOrEmpty(loginData.username) || string.IsNullOrEmpty(loginData.password))
                                {
                                    log.Warn("用户名或密码不能为空");
                                    var emptyResult = new LoginResultData { type = "login", status = "error_-1", message = "用户名或密码不能为空" };
                                    socket.Send(JsonSerializer.SerializeToUtf8Bytes(emptyResult));
                                    continue; // 如果用户名或密码为空，则跳过登录流程
                                }
                                if (loginData.username.Length < 2 || loginData.username.Length > 20)
                                {
                                    log.Warn($"用户登录时 {loginData.username} 用户名长度不符合要求");
                                    var lengthResult = new LoginResultData { type = "login", status = "error_2", message = "用户名长度必须在2到20个字符之间" };
                                    socket.Send(JsonSerializer.SerializeToUtf8Bytes(lengthResult));
                                    continue; // 如果用户名长度不符合要求，则跳过登录流程
                                }
                                var Authentication = UserAuthentication(loginData.username, loginData.password);
                                if (Authentication != "")
                                {
                                    log.Info($"用户 {loginData.username} 登录成功 (id:{Authentication})");
                                    var result = new LoginResultData
                                    {
                                        type = "login",
                                        status = "succeed",
                                        message = "登录成功",
                                        //token = Authentication,
                                        username = loginData.username,
                                        userid = Authentication
                                    };
                                    socket.Send(System.Text.Encoding.UTF8.GetBytes(JsonSerializer.Serialize(result)));
                                }
                                else
                                {
                                    log.Warn($"用户 {loginData.username} 登录失败，用户名或密码错误");
                                    var result = new LoginResultData { type = "login", status = "error_0", message = "用户名或密码错误" };
                                    socket.Send(System.Text.Encoding.UTF8.GetBytes(JsonSerializer.Serialize(result)));
                                }
                            }
                        }
                        else if (Type.type == "chat")
                        {
                            var chatData = JsonSerializer.Deserialize<ChatData>(message);
                            if (chatData != null && chatData.message != null)
                            {
                                log.Info($"接收到聊天消息: {chatData.message}");
                                var chatRegisterData = new ChatRegisterData
                                {
                                    type = "chat",
                                    userid = chatData.userid ?? "Unid",
                                    user = GetUsernameByUserId(chatData.userid!),
                                    message = chatData.message,
                                    msgtype = chatData.msgtype ?? MessageType.Text,
                                    // 替换为
                                    timestamp = DateTime.Now
                                };
                                foreach (var client in Client)
                                {
                                    client.Send(System.Text.Encoding.UTF8.GetBytes(JsonSerializer.Serialize(chatRegisterData)));
                                }
                            }
                            else
                            {
                                log.Warn("接收到无效的聊天消息");
                            }
                        }
                        else
                        {
                            log.Warn("未知的请求类型: " + Type.type);
                        }
                    }
                }
            }
            catch (SocketException ex)
            {
                log.Error("Socket error: " + ex.Message);
            }
            catch (JsonException ex)
            {
                log.Error("JSON parsing error: " + ex.Message);
            }
            catch (Exception ex)
            {
                log.Error("Error handling client: " + ex.Message);
            }
            finally
            {
                log.Info($"用户{socket.RemoteEndPoint}已断开连接");
                socket.Close();
                Client.Remove(socket);
            }
        }
        /// <summary>
        /// 查询User_db是否有相同用户名
        /// </summary>
        /// <param name="username"></param>
        /// <returns></returns>
        static bool UserExists(string username)
        {
            using var cmd = new SQLiteCommand("SELECT COUNT(*) FROM users WHERE username = @username", User_db);
            cmd.Parameters.AddWithValue("@username", username);
            var count = Convert.ToInt32(cmd.ExecuteScalar());
            return count > 0;
        }
        /// <summary>
        /// 验证用户登录信息并返回userid结果
        /// </summary>
        /// <param name="username"></param>
        /// <param name="password"></param>
        /// <returns></returns>
        static string UserAuthentication(string username, string password)
        {
            using var cmd = new SQLiteCommand("SELECT userid FROM users WHERE username = @username AND password = @password", User_db);
            cmd.Parameters.AddWithValue("@username", username);
            cmd.Parameters.AddWithValue("@password", password);
            var result = cmd.ExecuteScalar();
            return result != null ? result.ToString()! : string.Empty;
        }
        // 在ChatServer类中添加一个方法用于初始化users表
        private static void EnsureUsersTableExists()
        {
            using var cmd = new SQLiteCommand(@"
                CREATE TABLE IF NOT EXISTS users (
                    userid TEXT PRIMARY KEY,
                    username TEXT NOT NULL UNIQUE,
                    password TEXT NOT NULL
                )", User_db);
            cmd.ExecuteNonQuery();
        }
        /// <summary>
        /// 根据userid查询对应的用户名
        /// </summary>
        /// <param name="userid"></param>
        /// <returns>用户名，如果不存在则返回</returns>
        static string GetUsernameByUserId(string userid)
        {
            if (string.IsNullOrEmpty(userid) || userid == "Unid")
            {
                return "Unnamed"; // 如果userid为空或为"Unid"，返回默认用户名
            }
            using var cmd = new SQLiteCommand("SELECT username FROM users WHERE userid = @userid", User_db);
            cmd.Parameters.AddWithValue("@userid", userid);
            var result = cmd.ExecuteScalar();
            return result != null ? result.ToString()! : "Unnamed";
        }
        
    }
}