using Model;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection.Emit;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Permission
{
    public static class PermissionManager
    {
        public const PermissionLevel DefaultPermissionLevel = PermissionLevel.无权限;
        public static User CurrentUser { get => AppSession.CurrentUser; private set => AppSession.CurrentUser = value; }//当前的权限等级

        public static event Action<PermissionLevel> OnPermissionLevelChanged; // 定义一个事件，当权限级别改变时触发

        public static void SignIn(User user)
        {
            CurrentUser = user;
            OnPermissionLevelChanged?.Invoke(user.PermissionLevel);
        }
        public static void SignOut()
        {
            CurrentUser.PermissionLevel = DefaultPermissionLevel;
            CurrentUser.Username = "";

  
            // 触发事件：通知所有订阅者权限已变更
            OnPermissionLevelChanged?.Invoke(DefaultPermissionLevel);
        }
        public static void LogOffAndSignInOperator()
        {
            //SignOut();
            if (CurrentUser.PermissionLevel != PermissionLevel.操作工 && CurrentUser.PermissionLevel != PermissionLevel.开发者)
            {
                User user = new User(CurrentUser.Username + "_自动注销", "", PermissionLevel.操作工);
                SignIn(user);
            }
        }
        public static void ApplyPermissions(Form form)
        {
            foreach (Control control in GetAllControls(form))
            {
                // 控件本身实现了接口
                if (control is IPermissionControl pc)
                {
                    pc.CurrentPermissionLevel = CurrentUser.PermissionLevel;
                }
                else
                {
                    var hasPermission = CurrentUser.PermissionLevel >= control.GetPermissionLevel();
                    control.Enabled = hasPermission;
                    //control.Visible = hasPermission;
                    //if (control is Control c && !(c is Form))
                    //    c.Enabled = hasPermission;
                }
            }
        }
        private static IEnumerable<Control> GetAllControls(Control parent)
        {
            var controls = new List<Control>();
            foreach (Control ctrl in parent.Controls)
            {
                controls.Add(ctrl);
                if(!(ctrl is IPermissionControl pc) && ctrl.HasChildren)
                    controls.AddRange(GetAllControls(ctrl)); // 递归
            }
            return controls;
        }
        private static readonly object _lock = new object();
        private static bool _initialized = false;
        private static readonly Dictionary<PermissionLevel, PermissionProfile> roleProfiles = new Dictionary<PermissionLevel, PermissionProfile>();

        private static readonly string[] _roleFileNames = { "operator", "engineer", "technician", "admin" };
        private const string roleDir = "Role";
        /// <summary>
        /// 初始化权限管理器（建议在程序启动时调用一次）
        /// </summary>
        public static void Initialize()
        {
            if (_initialized) return;

            lock (_lock)
            {
                if (_initialized) return;

                for (int i = 0; i < _roleFileNames.Length; i++)
                {
                    string filePath = GetPermissionFilePath(_roleFileNames[i]);
                    if (File.Exists(filePath))
                    {
                        try
                        {
                            string json = File.ReadAllText(filePath);
                            var profile = JsonHelper.DeserializeFromString<PermissionProfile>(json) ?? new PermissionProfile();
                            roleProfiles[(PermissionLevel)i] = profile;
                        }
                        catch (Exception)
                        {
                            roleProfiles[(PermissionLevel)i] = new PermissionProfile(); // 损坏则新建
                        }
                    }
                    else
                    {
                        roleProfiles[(PermissionLevel)i] = new PermissionProfile(); // 文件不存在，空权限
                    }
                }

                _initialized = true;
            }
        }

        public static void ResetPermissions()
        {
            lock (_lock)
            {
                roleProfiles.Clear();
                _initialized = false;
                Initialize();
            }
        }

        private static string GetPermissionFilePath(string roleName)
        {
            return Path.Combine(Application.StartupPath, roleDir, $"permissions_{roleName}.json");
        }

        /// <summary>
        /// 获取指定角色被授权的控件列表
        /// </summary>
        /// <param name="role">0=操作工, 1=工程师, 2=技术员, 3=管理员</param>
        /// <returns>授权控件列表（只读副本）</returns>
        public static IReadOnlyList<AuthorizedControl> GetAuthorizedControlsForRole(PermissionLevel roleLevel)
        {
            if (!_initialized)
                Initialize(); // 懒加载（也可强制要求提前初始化）

            lock (_lock)
            {
                if (roleProfiles.TryGetValue(roleLevel, out var profile))
                {
                    // 返回副本，防止外部修改缓存
                    return profile.AuthorizedControls.ToList().AsReadOnly();
                }
                return new List<AuthorizedControl>();
            }
        }

        public static PermissionProfile GetRoleProfile(PermissionLevel roleLevel)
        {
            if (!_initialized)
                Initialize(); 

            lock (_lock)
            {
                if (roleProfiles.TryGetValue(roleLevel, out var profile))
                {

                    return profile;
                }
                return new PermissionProfile();
            }
        }
        public static void SaveRoleProfile(PermissionLevel roleLevel, PermissionProfile profile)
        {
            roleProfiles[roleLevel] = profile;

            string filePath = GetPermissionFilePath(_roleFileNames[(int)roleLevel]);
            JsonHelper.SerializeObject(filePath, profile);
        }

        /// <summary>
        /// （可选）检查某个控件对当前角色是否授权
        /// </summary>
        public static bool IsControlAuthorized(PermissionLevel roleLevel, string formType, string controlName)
        {
            var authorized = GetAuthorizedControlsForRole(roleLevel);
            return authorized.Any(c => c.FormType == formType && c.ControlName == controlName);
        }
    }
}