using System;
using System.Windows.Forms;
using 報到系統客戶端.Data.Repositories;
using 報到系統客戶端.Models;
using 報到系統客戶端.Services;

namespace 報到系統客戶端
{
    /// <summary>
    /// Session 狀態改變事件委派
    /// </summary>
    public delegate void OnModeChangeEventHandler(object sender, ModeChangeEventArgs e);

    /// <summary>
    /// Session 狀態改變事件參數
    /// </summary>
    public class ModeChangeEventArgs : EventArgs
    {
        public bool OnlineMode { get; set; }
        public string UserID { get; set; }
        public string UserName { get; set; }
        public DateTime ChangeTime { get; set; }
    }

    /// <summary>
    /// 客戶端 Session 管理
    /// 使用新的 ApiService 進行 API 呼叫
    /// </summary>
    public class ClientSession
    {
        private static ClientSession instance = null;
        private static readonly object lockObject = new object();

        private string userID = string.Empty;
        private string userName = string.Empty;
        private bool onlineMode = false;
        private DateTime loginTime = DateTime.MinValue;

        /// <summary>
        /// Session 狀態改變事件
        /// </summary>
        public static event OnModeChangeEventHandler OnModeChange;

        private ClientSession()
        {
        }

        private static void InitInstance()
        {
            if (instance == null)
            {
                lock (lockObject)
                {
                    if (instance == null)
                        instance = new ClientSession();
                }
            }
        }

        /// <summary>
        /// 觸發 Session 狀態改變事件
        /// </summary>
        private static void RaiseModeChangeEvent()
        {
            OnModeChange?.Invoke(null, new ModeChangeEventArgs
            {
                OnlineMode = instance.onlineMode,
                UserID = instance.userID,
                UserName = instance.userName,
                ChangeTime = DateTime.Now
            });
        }

        /// <summary>
        /// 程式版本號
        /// </summary>
        public static string Version
        {
            get
            {
                var version = System.Reflection.Assembly.GetExecutingAssembly().GetName().Version;
                return string.Format("版本 {0}.{1}.{2}", version.Major, version.Minor, version.Build);
                // Build: 8
                // Major: 2026
                // MajorRevision: 0
                // Minor: 2
                // MinorRevision: 0
                // Revision: 0
            }
        }

        /// <summary>
        /// 取得目前登入的使用者ID
        /// </summary>
        public static string UserID
        {
            get
            {
                InitInstance();
                return instance.userID;
            }
        }

        /// <summary>
        /// 取得目前登入的使用者名稱
        /// </summary>
        public static string UserName
        {
            get
            {
                InitInstance();
                return instance.userName;
            }
        }

        /// <summary>
        /// 取得是否為連線模式
        /// </summary>
        public static bool OnlineMode
        {
            get
            {
                InitInstance();
                return instance.onlineMode;
            }
        }

        /// <summary>
        /// 取得登入時間
        /// </summary>
        public static DateTime LoginTime
        {
            get
            {
                InitInstance();
                return instance.loginTime;
            }
        }

        /// <summary>
        /// 設定登入資訊
        /// </summary>
        internal static void SetLoginInfo(string userID, string userName, bool onLineMode)
        {
            InitInstance();
            instance.userID = userID;
            instance.userName = userName;
            instance.onlineMode = onLineMode;
            instance.loginTime = DateTime.Now;
            RaiseModeChangeEvent();
        }

        /// <summary>
        /// 檢查是否已登入，若未登入則導向登入畫面
        /// </summary>
        public static void CheckLogin()
        {
            InitInstance();

            BaseResponse response = LoginService.CheckSession();
            if (!response.Success)
            {
                ShowLoginForm();
            }
        }

        /// <summary>
        /// 進行心跳檢測
        /// </summary>
        public static void HeartBeat()
        {
            InitInstance();
            LoginService.CheckSession();
        }

        /// <summary>
        /// 進行通訊測試
        /// </summary>
        public static bool Ping()
        {
            InitInstance();
            return LoginService.Ping();
        }

        /// <summary>
        /// 執行登入（非同步版本）
        /// </summary>
        public static async System.Threading.Tasks.Task<(bool, string)> LoginAsync(string username, string password)
        {
            BaseResponse response = await LoginService.LoginAsync(username, password);
            if (response.Success)
            {
                try
                {
                    // 解析登入回應資料
                    dynamic data = response.Data;
                    string returnedUserID = data?.UserID ?? username;
                    string returnedUsername = data?.UserName ?? username;
                    SetLoginInfo(returnedUserID, returnedUsername, true);
                    return (true, string.Empty);
                }
                catch (Exception ex)
                {
                    SetLoginInfo(string.Empty, string.Empty, false);
                    return (false, string.Format("登入錯誤：{0}", ex.Message));
                }
            }
            return (false, response.Message);
        }

        /// <summary>
        /// 執行登入（同步版本）
        /// </summary>
        public static bool Login(string username, string password, out string message)
        {
            message = string.Empty;
            BaseResponse response = LoginService.Login(username, password);
            if (response.Success)
            {
                try
                {
                    // 解析登入回應資料
                    dynamic data = response.Data;
                    string returnedUserID = data?.UserID ?? username;
                    string returnedUsername = data?.UserName ?? username;
                    SetLoginInfo(returnedUserID, returnedUsername, true);
                    return true;
                }
                catch (Exception ex)
                {
                    SetLoginInfo(string.Empty, string.Empty, false);
                    message = string.Format("登入錯誤：{0}", ex.Message);
                    return false;
                }
            }
            message = response.Message;
            return false;
        }

        /// <summary>
        /// 執行登出
        /// </summary>
        public static void Logout()
        {
            InitInstance();
            LoginService.Logout();
            LoginService.ClearSession();
            instance.userID = string.Empty;
            instance.userName = string.Empty;
            instance.onlineMode = false;
            instance.loginTime = DateTime.MinValue;
            RaiseModeChangeEvent();
        }

        /// <summary>
        /// 顯示登入表單
        /// </summary>
        public static void ShowLoginForm()
        {
            var loginForm = new LoginForm();
            if (loginForm.ShowDialog() == DialogResult.Cancel)
            {
                Application.Exit();
            }
        }

        public static (bool, string) LoginOffline(string bpeno)
        {
            try
            {
                BPSNRepository bpsnRepo = new BPSNRepository();
                var bpsn = bpsnRepo.GetByBPENO(bpeno);
                if (bpsn == null) 
                {
                    return (false, "登入帳號錯誤");
                }
                SetLoginInfo(bpsn.BPENO, bpsn.BPNME, false);

                // 離線模式不驗證密碼
                // string combined = bpsn.BPENO + password;
                // using (SHA1 sha1 = SHA1.Create())
                // {
                //     byte[] hash = sha1.ComputeHash(Encoding.UTF8.GetBytes(combined));
                //     if (string.Compare(bpsn.BPAWD, Convert.ToBase64String(hash)) != 0)
                //     {
                //         return (false, "帳號或密碼錯誤");
                //     }
                // }

                return (true, string.Empty);
            }
            catch (Exception ex)
            {
                SetLoginInfo(string.Empty, string.Empty, false);
                return (false, string.Format("登入錯誤：{0}", ex.Message));
            }
        }
    }
}