using FATrace.Model;
using FATrace.WPLApp.Core;
using FATrace.WPLApp.Services;
using FreeSql;
using Prism.Commands;
using Prism.Services.Dialogs;
using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace FATrace.WPLApp.ViewModels
{
    /// <summary>
    /// 用户管理页面 VM（TbUser 增删改查）
    /// </summary>
    public class UserManageViewModel : NavigationViewModel
    {
        private readonly IFreeSql _fsql;
        private readonly ILogService _log;
        private readonly IDialogService _dialog;
        private readonly SysRunService _sys;

        public UserManageViewModel(IFreeSql fsql, ILogService log, IDialogService dialogService, SysRunService sys)
        {
            _fsql = fsql;
            _log = log;
            _dialog = dialogService;
            _sys = sys;

            AccessLevelOptions = new ObservableCollection<string>(new[] { AccessLevels.All, AccessLevels.Admin, AccessLevels.Operator, AccessLevels.Guest });
            AccessLevel = AccessLevels.All;
            Items = new ObservableCollection<TbUser>();

            SearchCommand = new DelegateCommand(async () => await SearchAsync(), () => !IsBusy)
                .ObservesProperty(() => IsBusy);
            ClearCommand = new DelegateCommand(ClearFilters, () => !IsBusy)
                .ObservesProperty(() => IsBusy);

            AddCommand = new DelegateCommand(AddUser, () => !IsBusy && CanEditUsers)
                .ObservesProperty(() => IsBusy)
                .ObservesProperty(() => CanEditUsers);
            EditCommand = new DelegateCommand(EditUser, () => !IsBusy && CanEditUsers && SelectedItem != null)
                .ObservesProperty(() => IsBusy)
                .ObservesProperty(() => CanEditUsers)
                .ObservesProperty(() => SelectedItem);
            DeleteCommand = new DelegateCommand(async () => await DeleteUserAsync(), () => !IsBusy && CanEditUsers && SelectedItem != null)
                .ObservesProperty(() => IsBusy)
                .ObservesProperty(() => CanEditUsers)
                .ObservesProperty(() => SelectedItem);

            FirstPageCommand = new DelegateCommand(async () => { if (PageIndex == 1) return; PageIndex = 1; await SearchAsync(); }, () => !IsBusy && PageIndex > 1)
                .ObservesProperty(() => IsBusy)
                .ObservesProperty(() => PageIndex);
            PrevPageCommand = new DelegateCommand(async () => { if (PageIndex <= 1) return; PageIndex -= 1; await SearchAsync(); }, () => !IsBusy && PageIndex > 1)
                .ObservesProperty(() => IsBusy)
                .ObservesProperty(() => PageIndex);
            NextPageCommand = new DelegateCommand(async () => { if (PageIndex >= TotalPages) return; PageIndex += 1; await SearchAsync(); }, () => !IsBusy && PageIndex < TotalPages)
                .ObservesProperty(() => IsBusy)
                .ObservesProperty(() => PageIndex)
                .ObservesProperty(() => TotalPages);
            LastPageCommand = new DelegateCommand(async () => { if (TotalPages <= 0 || PageIndex == TotalPages) return; PageIndex = TotalPages; await SearchAsync(); }, () => !IsBusy && PageIndex < TotalPages)
                .ObservesProperty(() => IsBusy)
                .ObservesProperty(() => PageIndex)
                .ObservesProperty(() => TotalPages);

            _sys.PropertyChanged += SysOnPropertyChanged;
            RaisePropertyChanged(nameof(CanEditUsers));
        }

        private void SysOnPropertyChanged(object? sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName == nameof(SysRunService.CurAccessLevel) || e.PropertyName == nameof(SysRunService.CurUser))
            {
                RaisePropertyChanged(nameof(CanEditUsers));
            }
        }

        /// <summary>
        /// 是否允许编辑用户（仅管理员）
        /// </summary>
        public bool CanEditUsers => string.Equals(_sys.CurAccessLevel, AccessLevels.Admin, StringComparison.OrdinalIgnoreCase);

        #region 查询条件
        private string? _userName;
        /// <summary>
        /// 用户名（模糊匹配）
        /// </summary>
        public string? UserName
        {
            get => _userName;
            set { _userName = value; RaisePropertyChanged(); }
        }

        private string? _accessLevel;
        /// <summary>
        /// 等级（精确匹配）
        /// </summary>
        public string? AccessLevel
        {
            get => _accessLevel;
            set { _accessLevel = value; RaisePropertyChanged(); }
        }

        /// <summary>
        /// 等级下拉选项
        /// </summary>
        public ObservableCollection<string> AccessLevelOptions { get; }
        #endregion

        #region 列表与分页
        public ObservableCollection<TbUser> Items { get; }

        private TbUser? _selectedItem;
        /// <summary>
        /// 当前选中行
        /// </summary>
        public TbUser? SelectedItem
        {
            get => _selectedItem;
            set { _selectedItem = value; RaisePropertyChanged(); }
        }

        private bool _isBusy;
        /// <summary>
        /// 是否忙碌
        /// </summary>
        public bool IsBusy
        {
            get => _isBusy;
            set { _isBusy = value; RaisePropertyChanged(); }
        }

        private int _totalCount;
        /// <summary>
        /// 总数
        /// </summary>
        public int TotalCount
        {
            get => _totalCount;
            set { _totalCount = value; RaisePropertyChanged(); }
        }

        private int _pageIndex = 1;
        /// <summary>
        /// 页码（从1开始）
        /// </summary>
        public int PageIndex
        {
            get => _pageIndex;
            set { _pageIndex = value < 1 ? 1 : value; RaisePropertyChanged(); }
        }

        private int _pageSize = 20;
        /// <summary>
        /// 页大小
        /// </summary>
        public int PageSize
        {
            get => _pageSize;
            set
            {
                var v = value <= 0 ? 20 : value;
                if (_pageSize != v)
                {
                    _pageSize = v;
                    RaisePropertyChanged();
                    PageIndex = 1;
                    if (!IsBusy) _ = SearchAsync();
                }
            }
        }

        private int _totalPages;
        /// <summary>
        /// 总页数
        /// </summary>
        public int TotalPages
        {
            get => _totalPages;
            set { _totalPages = value; RaisePropertyChanged(); }
        }
        #endregion

        #region 命令
        public DelegateCommand SearchCommand { get; }
        public DelegateCommand ClearCommand { get; }
        public DelegateCommand AddCommand { get; }
        public DelegateCommand EditCommand { get; }
        public DelegateCommand DeleteCommand { get; }

        public DelegateCommand FirstPageCommand { get; }
        public DelegateCommand PrevPageCommand { get; }
        public DelegateCommand NextPageCommand { get; }
        public DelegateCommand LastPageCommand { get; }
        #endregion

        private void ClearFilters()
        {
            UserName = string.Empty;
            AccessLevel = AccessLevels.All;
        }

        private async Task SearchAsync()
        {
            if (IsBusy) return;
            try
            {
                IsBusy = true;
                await SearchCoreAsync();
            }
            catch (Exception ex)
            {
                _log.Error($"TbUser 查询失败: {ex}");
                MessageBox.Show($"查询失败: {ex.Message}", "错误", MessageBoxButton.OK, MessageBoxImage.Error);
            }
            finally
            {
                IsBusy = false;
            }
        }

        private async Task SearchCoreAsync()
        {
            _log.Info("TbUser 查询开始");

            var data = await Task.Run(() =>
            {
                var q = _fsql.Select<TbUser>();

                if (!string.IsNullOrWhiteSpace(UserName))
                    q = q.Where(a => a.UserName != null && a.UserName.Contains(UserName));

                if (!string.IsNullOrWhiteSpace(AccessLevel)
                    && !string.Equals(AccessLevel, AccessLevels.All, StringComparison.OrdinalIgnoreCase))
                {
                    q = q.Where(a => a.AccessLevel == AccessLevel);
                }

                q = q.OrderByDescending(a => a.Id);

                var page = PageIndex < 1 ? 1 : PageIndex;
                var size = PageSize <= 0 ? 20 : PageSize;

                var list = q.Count(out var total)
                    .Page(page, size)
                    .ToList();

                var pages = total <= 0 || size <= 0 ? 0 : (int)Math.Ceiling(total * 1.0 / size);
                if (pages > 0 && page > pages)
                {
                    page = pages;
                    list = q.Page(page, size).ToList();
                }

                return (items: list, total: (int)total, normalizedPage: page, totalPages: pages);
            });

            Application.Current.Dispatcher.Invoke(() =>
            {
                Items.Clear();
                foreach (var it in data.items) Items.Add(it);
                TotalCount = data.total;
                TotalPages = data.totalPages;
                PageIndex = data.normalizedPage == 0 ? 1 : data.normalizedPage;
            });

            _log.Info($"TbUser 查询完成，记录数: {TotalCount}");
        }

        private void AddUser()
        {
            var p = new DialogParameters
            {
                { DialogKeys.Mode, DialogModes.Add }
            };

            _dialog.ShowDialog("DialogUserEditView", p, async r =>
            {
                if (r.Result == ButtonResult.OK)
                {
                    PageIndex = 1;
                    await SearchAsync();
                }
            });
        }

        private void EditUser()
        {
            if (SelectedItem == null)
            {
                MessageBox.Show("请选择要编辑的用户", "提示", MessageBoxButton.OK, MessageBoxImage.Information);
                return;
            }

            var p = new DialogParameters
            {
                { DialogKeys.Mode, DialogModes.Edit },
                { DialogKeys.UserId, SelectedItem.Id }
            };

            _dialog.ShowDialog("DialogUserEditView", p, async r =>
            {
                if (r.Result == ButtonResult.OK)
                {
                    await SearchAsync();
                }
            });
        }

        private async Task DeleteUserAsync()
        {
            if (SelectedItem == null)
            {
                MessageBox.Show("请选择要删除的用户", "提示", MessageBoxButton.OK, MessageBoxImage.Information);
                return;
            }

            if (!string.IsNullOrWhiteSpace(_sys.CurUser)
                && string.Equals(_sys.CurUser, SelectedItem.UserName, StringComparison.OrdinalIgnoreCase))
            {
                MessageBox.Show("不能删除当前登录用户", "提示", MessageBoxButton.OK, MessageBoxImage.Warning);
                return;
            }

            var ok = MessageBox.Show($"确认删除用户：{SelectedItem.UserName} ?", "确认", MessageBoxButton.YesNo, MessageBoxImage.Question);
            if (ok != MessageBoxResult.Yes) return;

            if (IsBusy) return;
            try
            {
                IsBusy = true;

                var id = SelectedItem.Id;
                await Task.Run(() =>
                {
                    _fsql.Delete<TbUser>(id).ExecuteAffrows();
                });

                _log.Info($"删除用户成功，Id={id}");
                SelectedItem = null;
                await SearchCoreAsync();
            }
            catch (Exception ex)
            {
                _log.Error($"删除用户失败: {ex}");
                MessageBox.Show($"删除失败: {ex.Message}", "错误", MessageBoxButton.OK, MessageBoxImage.Error);
            }
            finally
            {
                IsBusy = false;
            }
        }

        /// <summary>
        /// 进入页面自动加载
        /// </summary>
        /// <param name="navigationContext">导航上下文</param>
        public override async void OnNavigatedTo(Prism.Regions.NavigationContext navigationContext)
        {
            await SearchAsync();
        }

        /// <summary>
        /// 权限等级常量
        /// </summary>
        public static class AccessLevels
        {
            public const string All = "全部";
            public const string Admin = "管理员";
            public const string Operator = "操作员";
            public const string Guest = "访客";
        }

        /// <summary>
        /// 弹窗参数 Key
        /// </summary>
        public static class DialogKeys
        {
            public const string Mode = "Mode";
            public const string UserId = "UserId";
        }

        /// <summary>
        /// 弹窗模式
        /// </summary>
        public static class DialogModes
        {
            public const string Add = "Add";
            public const string Edit = "Edit";
        }
    }
}