prs/prs.desktop/Components/Calendar/Calendar.xaml.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Threading;
using Comal.Classes;
using InABox.Clients;
using InABox.Configuration;
using InABox.Core;
using InABox.DynamicGrid;
using InABox.WPF;
using Org.BouncyCastle.Asn1.X509.Qualified;
using Syncfusion.SfSkinManager;
using Syncfusion.UI.Xaml.Scheduler;
using Selection = InABox.Core.Selection;
using SelectionChangedEventArgs = System.Windows.Controls.SelectionChangedEventArgs;

namespace PRSDesktop
{
    public partial class Calendar
    {

        private enum Suppress
        {
            Selector,  // Prevent the Selector from Being Changed
            Calendar,  // Prevent the Calendar from Being Reconfigured
            Events,    // Prevent the Selectors from Responding to Events 
            Refresh,   // Stop the Data from Being refreshed    
            Settings   // Dont allow settings to be updated
        }

        private EventSuppressor suppressor = null;
        public void DisableUpdate()
        {
            if (suppressor == null)
                suppressor = new EventSuppressor(Suppress.Refresh, Suppress.Settings);
        }

        public void EnableUpdate()
        {
            if (suppressor != null)
            {
                suppressor.Dispose();
                suppressor = null;
            }

            Refresh();
        }
        
        private void DoSetValue<T>(DependencyProperty property, T value, Action? updateselector, Action? updateinterface)
        {

            SetValue(property, value);
        
            if (!EventSuppressor.IsSet(Suppress.Selector) && (updateselector != null))
                using (new EventSuppressor(Suppress.Events))
                    updateselector();

            if (!EventSuppressor.IsSet(Suppress.Calendar) && (updateinterface != null))
                updateinterface();

            if (!EventSuppressor.IsSet(Suppress.Refresh))
                Refresh();

            if (!EventSuppressor.IsSet(Suppress.Settings))
            {
                Properties.SettingsVisible = SettingsVisible;
                Properties.Date = SelectedDate;
                Properties.StartHour = (int)Bookings.DaysViewSettings.StartHour;
                Properties.EndHour = (int)Bookings.DaysViewSettings.EndHour;
                Properties.CalendarView = CalendarView;
                Properties.EmployeeSelector = EmployeeSettings;
                Properties.EmployeeSelection = EmployeeSelection;
                Properties.TimeInterval = TimeInterval;
                Properties.AssignmentType = AssignmentType;
                Properties.BackgroundType = BackgroundType;
                Properties.Zoom = Zoom;
                SaveSettings?.Invoke(this, Properties);
            }
        }
        
        #region SettingsVisible Dependency Property
        
        public static readonly DependencyProperty SettingsVisibleProperty =
            DependencyProperty.Register(
                nameof(SettingsVisible), 
                typeof(CalendarSettingsVisibility), 
                typeof(Calendar), 
                new UIPropertyMetadata(CalendarSettingsVisibility.Hidden)
            );
        
        public CalendarSettingsVisibility SettingsVisible
        {
            get => (CalendarSettingsVisibility)GetValue(SettingsVisibleProperty);
            set => SetSettingsVisibility(value);
        }

        private void SetSettingsVisibility(CalendarSettingsVisibility value)
        {
            DoSetValue(
                SettingsVisibleProperty,
                value,
                null,
                () =>
                {
                    VisibleSettingsColumn.Width = value == CalendarSettingsVisibility.Visible
                        ? new GridLength(240, GridUnitType.Pixel)
                        : new GridLength(0, GridUnitType.Pixel);
                    HiddenSettingsColumn.Width = value == CalendarSettingsVisibility.Hidden
                        ? new GridLength(35, GridUnitType.Pixel)
                        : new GridLength(0, GridUnitType.Pixel);

                }
            );
        }
        
        private void HideSideBar_OnClick(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetSettingsVisibility(CalendarSettingsVisibility.Hidden);
        }
        
        private void ShowSideBar_OnClick(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetSettingsVisibility(CalendarSettingsVisibility.Visible);
        }
        
        #endregion
        
        #region CalendarView Dependency Property
        
        public static readonly DependencyProperty CalendarViewProperty =
            DependencyProperty.Register(
                nameof(CalendarView), 
                typeof(CalendarViewType), 
                typeof(Calendar), 
                new UIPropertyMetadata(CalendarViewType.Day)
            );
        
        public CalendarViewType CalendarView
        {
            get => (CalendarViewType)GetValue(CalendarViewProperty);
            set => SetCalendarView(value);
        }
        
        private void SetCalendarView(CalendarViewType value)
        {
            DoSetValue(
                CalendarViewProperty,
                value,
                () => CalendarViewSelector.SelectedIndex = (int)value,
                () =>
                {
                    Bookings.ViewType = value switch
                    {
                        CalendarViewType.Day => SchedulerViewType.Day,
                        CalendarViewType.WorkWeek => SchedulerViewType.WorkWeek,
                        CalendarViewType.Week => SchedulerViewType.Week
                    };
                    ResizeColumns(this.ActualWidth);
                }
            );
        }
        
        private void CalendarViewSelector_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetCalendarView((CalendarViewType)CalendarViewSelector.SelectedIndex);
        }

        #endregion
        
        #region EmployeeSelector Dependency Property
        
        public static readonly DependencyProperty EmployeeSelectionProperty =
            DependencyProperty.Register(
                nameof(EmployeeSelection), 
                typeof(EmployeeSelectorData), 
                typeof(Calendar), 
                new UIPropertyMetadata(new EmployeeSelectorData())
            );
        
        public EmployeeSelectorData EmployeeSelection
        {
            get => (EmployeeSelectorData)GetValue(EmployeeSelectionProperty);
            set => SetEmployeeSelection(value);
        }
        
        private void SetEmployeeSelection(EmployeeSelectorData value)
        {
            DoSetValue(
                EmployeeSelectionProperty,
                value,
                () => EmployeeSelector.Selection = value,
                () =>
                {
                    _employees = EmployeeSelector.GetEmployeeData((row) => new EmployeeResourceModel(row));
                    ReloadColumns();
                }
            );
        }
        
        private void EmployeeSelector_OnSelectionChanged(object sender, EmployeeSelectorSelectionChangedArgs args)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetEmployeeSelection(args.Selection);
        }
        
        #endregion
        
        #region EmployeeSettings Dependency Property
        
        public static readonly DependencyProperty EmployeeSettingsProperty =
            DependencyProperty.Register(
                nameof(EmployeeSettings), 
                typeof(EmployeeSelectorSettings), 
                typeof(Calendar), 
                new UIPropertyMetadata(new EmployeeSelectorSettings())
            );
        
        public EmployeeSelectorSettings EmployeeSettings
        {
            get => (EmployeeSelectorSettings)GetValue(EmployeeSettingsProperty);
            set => SetEmployeeSettings(value);
        }
        
        private void SetEmployeeSettings(EmployeeSelectorSettings value)
        {
            DoSetValue(
                EmployeeSettingsProperty,
                value,
                () => EmployeeSelector.Settings = value,
                () =>
                {
                    // Nothing to do here
                }
            );
        }

        private void EmployeeSelector_OnSettingsChanged(object sender, EmployeeSelectorSettingsChangedArgs args)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetEmployeeSettings(args.Settings);
        }

        #endregion
        
        #region TimeInterval DependencyProperty
        
        public static readonly DependencyProperty TimeIntervalProperty =
            DependencyProperty.Register(
                "TimeInterval", 
                typeof(CalendarTimeInterval), 
                typeof(Calendar),
                new PropertyMetadata(CalendarTimeInterval.FifteenMinutes)
            );

        public CalendarTimeInterval TimeInterval
        {
            get => (CalendarTimeInterval)GetValue(TimeIntervalProperty);
            set => SetTimeInterval(value);
        }

        private void SetTimeInterval(CalendarTimeInterval value)
        {
            DoSetValue(
                TimeIntervalProperty,
                value,
                () => IntervalSelector.SelectedIndex = (int)value,
                () =>
                {
                    Bookings.DaysViewSettings.TimeInterval = TimeIntervalToTimeSpan(value);
                    UpdateZoom();
                });
        }
        
        private void IntervalSelector_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetTimeInterval((CalendarTimeInterval)IntervalSelector.SelectedIndex);
        }

        public TimeSpan TimeIntervalToTimeSpan(CalendarTimeInterval interval)
        {
            return interval switch
            {
                CalendarTimeInterval.FiveMinutes => new TimeSpan(0, 5, 0),
                CalendarTimeInterval.SixMinutes => new TimeSpan(0, 6, 0),
                CalendarTimeInterval.TenMinutes => new TimeSpan(0, 10, 0),
                CalendarTimeInterval.FifteenMinutes => new TimeSpan(0, 15, 0),
                CalendarTimeInterval.TwentyMinutes => new TimeSpan(0, 20, 0),
                CalendarTimeInterval.ThirtyMinutes => new TimeSpan(0, 30, 0),
                _ => new TimeSpan(1, 0, 0)
            };           
        }
        
        public int BlocksPerHour(CalendarTimeInterval interval)
        {
            return interval switch
            {
                CalendarTimeInterval.FiveMinutes => 12,
                CalendarTimeInterval.SixMinutes => 10,
                CalendarTimeInterval.TenMinutes => 6,
                CalendarTimeInterval.FifteenMinutes => 4,
                CalendarTimeInterval.TwentyMinutes => 3,
                CalendarTimeInterval.ThirtyMinutes => 2,
                _ => 1
            };           
        }

        private TimeSpan AdjustStartTime(TimeSpan time)
        {
            long blocksize = TimeIntervalToTimeSpan(TimeInterval).Ticks;
            //long blocksperday = TimeSpan.FromDays(1).Ticks / ;
            long blocknumber = time.Ticks / blocksize;
            long blockstart = blocknumber * blocksize;
            return TimeSpan.FromTicks(blockstart);
        }
        
        #endregion
        
        #region SelectedDate Dependency Property
        
        public static readonly DependencyProperty SelectedDateProperty =
            DependencyProperty.Register(
                nameof(SelectedDate), 
                typeof(DateTime), 
                typeof(Calendar), 
                new UIPropertyMetadata(DateTime.Today)
            );

        public DateTime SelectedDate
        {
            get => (DateTime)GetValue(SelectedDateProperty);
            set => SetSelectedDate(value);
        }

        private void SetSelectedDate(DateTime value)
        {
            DoSetValue(
                SelectedDateProperty,
                value,
                () => DateSelector.Date = value,
                () =>
                {
                    Bookings.DisplayDate = value;
                    Bookings.SelectedDate = value;                    
                }
            );
        }

        private void DateSelector_DateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetSelectedDate(DateSelector.Date);
        }

        public DateTime StartDate => Properties.CalendarView == CalendarViewType.Day
            ? SelectedDate
            : SelectedDate.StartOfWeek(DayOfWeek.Monday);

        public DateTime EndDate => Properties.CalendarView == CalendarViewType.Day
            ?  StartDate.AddDays(1)
            : Properties.CalendarView == CalendarViewType.WorkWeek
                ? StartDate.AddDays(5)
                : StartDate.AddDays(7);
        
        #endregion
        
        #region StartHour Dependency Properties
        
        public static readonly DependencyProperty StartHourProperty =
            DependencyProperty.Register(
                nameof(StartHour), 
                typeof(int), 
                typeof(Calendar), 
                new UIPropertyMetadata(6)
            );
        
        public int StartHour
        {
            get => (int)GetValue(StartHourProperty);
            set => SetStartHour(value);
        }
        
        private void SetStartHour(int value)
        {
            value = Math.Min(EndHour-1,Math.Max(0, value));
            DoSetValue(
                StartHourProperty, 
                value,
                () => StartTimeSelector.Text = FormatHour(value),
                () =>
                {
                    Bookings.DaysViewSettings.StartHour = value;
                    UpdateZoom();
                });
        }
        
        private void StartTimeSelector_Down_Click(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            SetStartHour(StartHour - 1);
        }

        private void StartTimeSelector_Up_Click(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            SetStartHour(StartHour + 1);
        }
        
        #endregion
        
        #region End Hour Property
        
        public static readonly DependencyProperty EndHourProperty =
            DependencyProperty.Register(
                nameof(EndHour), 
                typeof(int), 
                typeof(Calendar), 
                new UIPropertyMetadata(18)
            );

        public int EndHour
        {
            get => (int)GetValue(EndHourProperty);
            set => SetEndHour(value);
        }

        private void SetEndHour(int value)
        {
            value = Math.Max(StartHour + 1, Math.Min(24, value));
            DoSetValue(
                EndHourProperty,
                value,
                () => FinishTimeSelector.Text = FormatHour(value),
                () =>
                {
                    Bookings.DaysViewSettings.EndHour = value;
                    UpdateZoom();
                });
        }
        
        private void FinishTimeSelector_Down_Click(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            SetEndHour(EndHour - 1);
        }

        private void FinishTimeSelector_Up_Click(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            SetEndHour(EndHour + 1);
        }
        
        private string FormatHour(int hour)
        {
            return hour <= 0 || hour >= 24
                ? "Midnight"
                : hour < 12
                    ? string.Format("{0}:00 AM", hour)
                    : hour > 12
                        ? string.Format("{0}:00 PM", hour)
                        : "12:00 NN";
        }
        
        #endregion       
        
        #region AssignmentType Dependency Property
        
        public static readonly DependencyProperty AssignmentTypeProperty =
            DependencyProperty.Register(
                nameof(AssignmentType), 
                typeof(CalendarAssignmentType), 
                typeof(Calendar), 
                new UIPropertyMetadata(CalendarAssignmentType.Booked)
            );
        
        public CalendarAssignmentType AssignmentType
        {
            get => (CalendarAssignmentType)GetValue(AssignmentTypeProperty);
            set => SetAssignmentType(value);
        }

        private void SetAssignmentType(CalendarAssignmentType value)
        {
            DoSetValue(
                AssignmentTypeProperty,
                value,
                () => AssignmentTypeSelector.SelectedIndex = (int)value,
                null
            );
        }

        private void AssignmentTypeSelector_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetAssignmentType((CalendarAssignmentType)AssignmentTypeSelector.SelectedIndex);
        }
        
        #endregion
        
        #region BackgroundType Dependency Property
        
        public static readonly DependencyProperty BackgroundTypeProperty =
            DependencyProperty.Register(
                nameof(BackgroundType), 
                typeof(CalendarBackgroundType), 
                typeof(Calendar), 
                new UIPropertyMetadata(CalendarBackgroundType.Roster)
            );
        
        public CalendarBackgroundType BackgroundType
        {
            get => (CalendarBackgroundType)GetValue(BackgroundTypeProperty);
            set => SetBackgroundType(value);
        }
        
        private void SetBackgroundType(CalendarBackgroundType type)
        {
            DoSetValue(
                BackgroundTypeProperty,
                type,
                () => BackgroundTypeSelector.SelectedIndex = (int)type,
                null
            );
        }

        private void BackgroundTypeSelector_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            using (new EventSuppressor(Suppress.Selector))
                SetBackgroundType((CalendarBackgroundType)BackgroundTypeSelector.SelectedIndex);
        }

        #endregion
        
        #region Zoom Dependency Properties
        
        public static readonly DependencyProperty ZoomProperty =
            DependencyProperty.Register(
                nameof(Zoom), 
                typeof(double), 
                typeof(Calendar), 
                new UIPropertyMetadata((double)100F)
            );
        
        public double Zoom
        {
            get => (double)GetValue(ZoomProperty);
            set => SetZoom(value);
        }
        
        private void SetZoom(double value)
        {
            DoSetValue(
                ZoomProperty, 
                value,
                () => ZoomSelector.Text = $"{value:F0}%",
                () =>  UpdateZoom()
            );
        }

        private void UpdateZoom()
        {
            if (double.IsNaN(this.ActualHeight) || (this.ActualHeight == 0.0F))
                return;
            var blocksize = (this.ActualHeight - (Bookings.DaysViewSettings.ViewHeaderHeight + Bookings.DaysViewSettings.ResourceHeaderSize + 2.0F)) / ((EndHour - StartHour) * this.BlocksPerHour(TimeInterval));
            Bookings.DaysViewSettings.TimeIntervalSize = (double)Zoom * blocksize / 100.0F;
        }

        private void ZoomSelector_Down_Click(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            ZoomOut();
        }
        
        private void ZoomSelector_Up_Click(object sender, RoutedEventArgs e)
        {
            if (EventSuppressor.IsSet(Suppress.Events))
                return;
            ZoomIn();
        }

        public void ZoomIn() => SetZoom(Zoom * 1.125F);
        public void ZoomOut() => SetZoom(Zoom / 1.125F);
        public void ResetZoom() => SetZoom(100.0F);
        
        #endregion
        
        #region Event Handlers
        
        public event LoadSettings<CalendarSettings> LoadSettings;
        
        public event SaveSettings<CalendarSettings> SaveSettings;

        public CalendarConfigurationEvent ConfigurationChanged;
        
        public event CalendarDataEvent CustomiseContextMenu;
        
        public event CalendarDataEvent SelectionChanged;

        public event CalendarDataEvent ItemCreated;        
        
        public event CalendarDataEvent ItemChanged;

        public event CalendarHandledEvent ItemEditing;
        
        #endregion

        public void SelectEmployee(Guid employeeid) => EmployeeSelector.SelectEmployee(employeeid);

        // Populated as requiew when EmployeeSelector.SelectionChanged is triggered
        private EmployeeResourceModel[] _employees = new EmployeeResourceModel[] { };
        
        // Populated once at startup
        private StandardLeaveModel[] _standardleaves = new StandardLeaveModel[] { };
        private LeaveRequestModel[] _leaverequests = new LeaveRequestModel[] { };

        // Populated on each Refresh
        private TimeSheetModel[] _timesheets = new TimeSheetModel[] { };
        
        // Populated on each Refresh
        private List<AssignmentModel> _assignments = new List<AssignmentModel>();
        
        private bool bColumnsLoaded;
        
        private AssignmentGrid ag;
        private DynamicDataGrid<Meeting> mg;
        
        public bool IsReady { get; set; }
        
        public CalendarSettings Properties { get; set; }
        
        public Calendar()
        {
            using (EventSuppressor.All<Suppress>())
            {
                InitializeComponent();
                SetValue(StartHourProperty, 0);
                SetValue(EndHourProperty, 24);
                
                // Force the Calendar to display Monday - Sunday
                CultureInfo cultureInfo = new CultureInfo(CultureInfo.CurrentCulture.Name);
                cultureInfo.DateTimeFormat.FirstDayOfWeek = DayOfWeek.Monday; 
                DateSelector.Culture = cultureInfo; 
                
                SfSkinManager.SetTheme(Bookings, new Theme() { ThemeName = "Office2019White", ScrollBarMode = ScrollBarMode.Compact });
                
            }
        }
        
        public virtual void Setup()
        {
            using (new EventSuppressor(Suppress.Settings, Suppress.Refresh, Suppress.Events))
            {
         
                Properties = LoadSettings?.Invoke(this) ?? new CalendarSettings();
                
                SetCalendarView(Properties.CalendarView);
                SetSettingsVisibility(Properties.SettingsVisible);
                SetSelectedDate(Properties.Date);
                SetStartHour(Properties.StartHour);
                SetEndHour(Properties.EndHour);
                SetTimeInterval(Properties.TimeInterval);
                SetAssignmentType(Properties.AssignmentType);
                SetBackgroundType(Properties.BackgroundType);
                SetCalendarView(Properties.CalendarView);
                SetZoom(Properties.Zoom);
                EmployeeSelector.Setup();
                SetEmployeeSettings(Properties.EmployeeSelector);
                SetEmployeeSelection(Properties.EmployeeSelection);
                
                _employees = EmployeeSelector.GetEmployeeData((row) => new EmployeeResourceModel(row));
                
                MultiQuery query = new MultiQuery();
                
                query.Add(
                    new Filter<LeaveRequest>(x=>x.Status).IsNotEqualTo(LeaveRequestStatus.Rejected), 
                    LeaveRequestModel.Columns
                );
                
                query.Add(
                    null,
                    StandardLeaveModel.Columns
                );

                query.Query();

                _standardleaves = query.Get<StandardLeave>().Rows.Select(row => new StandardLeaveModel(row)).ToArray();
                _leaverequests = query.Get<LeaveRequest>().Rows.Select(row => new LeaveRequestModel(row)).ToArray();

                var widthtimer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(100) };
                widthtimer.Tick += (o, e) =>
                {
                    if (Bookings.ActualWidth > 0.0F)
                    {
                        widthtimer.IsEnabled = false;
                        ReloadColumns();
                    }
                };
                widthtimer.IsEnabled = true;
            
            }
        }
        
        public virtual void Shutdown()
        {
        }
        
        public virtual void Refresh()
        {
            if (EventSuppressor.IsSet(Suppress.Refresh))
                return;
            using (new WaitCursor())
            {

                if (!bColumnsLoaded)
                    ReloadColumns();

                MultiQuery query = new MultiQuery();

                var empids = _employees.Select(x => x.ID).ToArray();
                
                if (BackgroundType != CalendarBackgroundType.Roster)
                {
                    query.Add<TimeSheet>(
                        new Filter<TimeSheet>(x => x.EmployeeLink.ID).InList(empids)
                            .And(x => x.Date).IsGreaterThanOrEqualTo(StartDate)
                            .And(x => x.Date).IsLessThanOrEqualTo(EndDate)
                            .And(x=>x.LeaveRequestLink.ID).IsEqualTo(Guid.Empty)
                            .And(x=>x.StandardLeaveLink.ID).IsEqualTo(Guid.Empty),
                        TimeSheetModel.Columns
                    );
                }
                
                query.Add<Assignment>(
                    new Filter<Assignment>(x => x.EmployeeLink.ID).InList(empids)
                        .And(x => x.Date).IsGreaterThanOrEqualTo(StartDate)
                        .And(x => x.Date).IsLessThanOrEqualTo(EndDate),
                    AssignmentModel.Columns,
                    new SortOrder<Assignment>(x => x.EmployeeLink.ID).ThenBy(x => x.Date).ThenBy(x => x.Booked.Duration, SortDirection.Descending)
                );
                
                query.Query();
                
                _timesheets = (BackgroundType == CalendarBackgroundType.Roster)
                    ? new TimeSheetModel[] { }
                    : query.Get<TimeSheet>().Rows.Select(r => new TimeSheetModel(r)).ToArray();
                
                _assignments = query.Get<Assignment>().Rows.Select(r => new AssignmentModel(r)).ToList();
                
                LoadBackground();

                var appointments = new CalendarAppointments();
                LoadStandardLeaves(appointments);
                LoadLeaveRequests(appointments);
                LoadAssignments(appointments);
 
                try
                {
                    Bookings.DisplayDate = Bookings.SelectedDate.HasValue ? Bookings.SelectedDate.Value : StartDate;
                    Bookings.ItemsSource = appointments;
                }
                catch (Exception e)
                {
                    Logger.Send(LogType.Error, "", string.Format("*** Unknown Error: {0}\n{1}", e.Message, e.StackTrace));
                }
            }
        }

        public EmployeeRosterItem GetRoster(Guid employeeid, DateTime date)
        {
            var employee = _employees.FirstOrDefault(x => x.ID == employeeid);
            var roster = RosterUtils.GetRoster(employee?.Roster, employee?.Start, date);
            return roster;
        }

        public bool GetActiveWindow(Guid employeeid, DateTime date, ref TimeSpan start, ref TimeSpan finish)
        {
            bool result = false;
            

            foreach (var assignment in _assignments.Where(a => (a.EmployeeID == employeeid) && (a.Date) == date))
            {
                result = true;
                var curstart = AssignmentType switch
                {
                    CalendarAssignmentType.Booked => assignment.BookedStart,
                    CalendarAssignmentType.Actual => assignment.ActualStart,
                    _ => Assignment.EffectiveTime(assignment.ActualStart, assignment.BookedStart)
                };
                
                var curfinish = AssignmentType switch
                {
                    CalendarAssignmentType.Booked => assignment.BookedFinish,
                    CalendarAssignmentType.Actual => assignment.ActualFinish,
                    _ => Assignment.EffectiveTime(
                            assignment.ActualFinish, 
                            Assignment.EffectiveTime(assignment.ActualStart, assignment.BookedStart)
                            .Add(assignment.BookedDuration)
                    )
                };
                
                start = start > curstart ? curstart : start;
                finish = finish < curfinish ? curfinish : finish;
            }

            if ((BackgroundType == CalendarBackgroundType.Roster) ||
                ((BackgroundType == CalendarBackgroundType.Automatic) && (date >= DateTime.Today)))
            {
                var employee = _employees.FirstOrDefault(x => x.ID == employeeid);
                if (employee != null)
                {
                    var roster = RosterUtils.GetRoster(employee.Roster, employee.Start, date);
                    if (roster != null)
                    {
                        var blocks = roster.GetBlocks(date, TimeSpan.MinValue, TimeSpan.MaxValue);
                        foreach (var block in blocks)
                        {
                            start = start > block.Start ? block.Start : start;
                            finish = finish < block.Finish ? block.Finish : finish;
                        }
                    }
                }
            }
            else
            {
                foreach (var timesheet in _timesheets.Where(t => (t.EmployeeID == employeeid) && (t.Date == date)))
                {
                    result = true;
                    var curstart = !timesheet.Approved.IsEmpty()
                        ? timesheet.ApprovedStart
                        : timesheet.Start;
                    var curfinish = !timesheet.Approved.IsEmpty()
                        ? timesheet.ApprovedFinish
                        : timesheet.Finish;
                    start = start > curstart ? curstart : start;
                    finish = finish < curfinish ? curfinish : finish;                   
                }                
            }
            
            return result;
        }

        public CoreRow[] GetAssignments(Guid employeeid, DateTime date)
        {
            return _assignments.Where(a => (a.Row != null) && (a.EmployeeID == employeeid) && (a.Date == date)).Select(x => x.Row!).ToArray();
        }
        
        public void UpdateAssignment(Assignment assignment)
        {
            
            void UpdateCalendar<TEntity, TModel>(
                TEntity entity, 
                List<TModel> collection,
                Action<TModel> refresh
            ) where TEntity : Entity where TModel : class, IModel
            {
                
                if (Bookings.ItemsSource is CalendarAppointments appointments)
                {
                    var appointment = appointments.FirstOrDefault(x => (Guid)x.Id == entity.ID) as ScheduleAppointment;
                    if (appointment != null)
                    {
                        appointments.Remove(appointment);
                        var calappt = appointment as ICalendarAppointment<TModel>;
                        if (calappt != null)
                            collection.Remove(calappt.Model);
                    }

                    var table = new CoreTable();
                    table.LoadColumns(typeof(TEntity));
                    var row = table.NewRow();
                    table.LoadRow(row, entity);
                    var model = Activator.CreateInstance(typeof(TModel),row) as TModel;
                    collection.Add(model);
                    refresh(model);

                }

            }
            
            if (Bookings.ItemsSource is CalendarAppointments appointments)
                UpdateCalendar(assignment, _assignments, (model) => LoadAssignment(model,appointments));
            
        }
        
        private void LoadBackground()
        {
            var regions = new ObservableCollection<SpecialTimeRegion>();
            foreach (var resource in Bookings.ResourceCollection)
            {
                var sEmpID = ((SchedulerResource)resource).Id as string;
                var empid = Guid.Parse(sEmpID);
                var employee = _employees.FirstOrDefault(x => x.ID == empid);
                for (var date = StartDate; date < EndDate; date = date.AddDays(1))
                {

                    if ((BackgroundType == CalendarBackgroundType.Roster) ||
                        ((BackgroundType == CalendarBackgroundType.Automatic) && (date >= DateTime.Today)))
                    {
                        var roster = RosterUtils.GetRoster(employee?.Roster, employee?.Start, date);
                        if (roster != null)
                        {
                            var blocks = roster.GetBlocks(date, TimeSpan.FromSeconds(0), TimeSpan.FromDays(1));
                            foreach (var block in blocks)
                            {
                                regions.Add(
                                    new SpecialTimeRegion
                                    {
                                        StartTime = date.Add(block.Start),
                                        EndTime = date.Add(block.Finish.Subtract(TimeSpan.FromSeconds(1))),
                                        ResourceIdCollection = new ObservableCollection<object> { ((SchedulerResource)resource).Id },
                                        Background = new SolidColorBrush(Colors.Yellow) {Opacity = 0.3},
                                        Foreground = new SolidColorBrush(Colors.Black),
                                        Text = ""
                                    }
                                );
                            }
                        }
                        
                    }
                    else
                    {
                        foreach (var timesheet in _timesheets.Where(t => (t.EmployeeID == empid) && (t.Date == date)))
                        {
                            
                            var start = !timesheet.Approved.IsEmpty()
                                ? timesheet.ApprovedStart
                                : timesheet.Start;
                            var finish = !timesheet.Approved.IsEmpty()
                                ? timesheet.ApprovedFinish
                                : timesheet.Finish;
                            regions.Add(
                                new SpecialTimeRegion
                                {
                                    StartTime = date.Add(start),
                                    EndTime = date.Add(finish),
                                    ResourceIdCollection = new ObservableCollection<object> { ((SchedulerResource)resource).Id },
                                    Background = new SolidColorBrush(!timesheet.Approved.IsEmpty() ? Colors.LightGreen : Colors.LightSalmon) { Opacity = 0.4 },
                                    Foreground = new SolidColorBrush(Colors.Transparent),
                                    Text = "",
                                    CanMergeAdjacentRegions = false
                                }
                            );
                        } 
                            
                    }


                }
            }
            Bookings.DaysViewSettings.SpecialTimeRegions = regions;
        }
        
        private void LoadStandardLeaves(CalendarAppointments appointments)
        {
            for (var date = StartDate; date < EndDate; date = date.AddDays(1))
            {
                var leaves = _standardleaves.Where(x => 
                    (x.From <= date)
                    && (x.To.Add(x.ToTime) > date)
                ).ToArray();
                foreach (var leave in leaves)
                {
                    
                    foreach (var resource in Bookings.ResourceCollection)
                    {

                        var sEmpID = ((SchedulerResource)resource).Id as string;
                        var empid = Guid.Parse(sEmpID);
                        var employee = _employees.FirstOrDefault(x => x.ID == empid);

                        var start = (date.Date == leave.From.Date) ? leave.FromTime : TimeSpan.FromSeconds(0);
                        var finish = (date.Date == leave.To.Date) ? leave.ToTime : TimeSpan.FromDays(1).Subtract(TimeSpan.FromSeconds(1));

                        var roster = RosterUtils.GetRoster(employee?.Roster, employee?.Start, date);
                        if (roster != null)
                        {
                            var blocks = roster.GetBlocks(date, start, finish);
                            foreach (var block in blocks)
                            {
                                var appt = new StandardLeaveAppointment(leave, _ => empid, x => x.Color, block);
                                appointments.Add(appt);
                            }
                        }
                    }

                }
            }
        }

        private void LoadLeaveRequests(CalendarAppointments appointments)
        {
            for (var date = StartDate; date < EndDate; date = date.AddDays(1))
            {

                var ids = Bookings.ResourceCollection
                    .Cast<SchedulerResource>()
                    .Where(x=>!String.IsNullOrWhiteSpace(x.Id as String))
                    .Select(x => Guid.Parse(x.Id.ToString() ?? ""));

                var leaves = _leaverequests.Where(x => 
                    (x.From <= date) 
                    && (x.To.Add(x.ToTime) > date) 
                    && ids.Contains(x.EmployeeID) 
                ).ToArray();

                foreach (var leave in leaves)
                {
                    var employee = _employees.FirstOrDefault(x => x.ID == leave.EmployeeID);
                    
                    var roster = RosterUtils.GetRoster(employee?.Roster, employee?.Start, date);
                    if (roster != null)
                    {
                        var start = (date.Date == leave.From.Date) ? leave.FromTime : TimeSpan.FromSeconds(0);
                        var finish = (date.Date == leave.To.Date) ? leave.ToTime : TimeSpan.FromDays(1).Subtract(TimeSpan.FromSeconds(1));
                        var blocks = roster.GetBlocks(date, start, finish);
                        foreach (var block in blocks)
                        {
                            var appt = new LeaveRequestAppointment(leave, x=>x.EmployeeID, x => x.Color, block);
                            appointments.Add(appt);
                        }
                    }
                }
            }
        }
        
        private void LoadAssignment(AssignmentModel assignment, CalendarAppointments appointments)
        {
            var model = new AssignmentAppointment(assignment, x => x.EmployeeID, x => x.Color, AssignmentType);
            appointments.Add(model);
        }

        private void LoadAssignments(CalendarAppointments appointments)
        {
            foreach (var assignment in _assignments)
                LoadAssignment(assignment, appointments);
        }
        
        public DataModel DataModel(Selection selection)
        {
            var ids = _assignments.Select(x => x.ID).ToArray();
            return new AutoDataModel<Assignment>(new Filter<Assignment>(x => x.ID).InList(ids));
        }

        // private void ResizeIntervals(double height)
        // {
        //     if (Bookings.FindVisualChildren<ScrollPanel>().Any())
        //     {
        //         
        //         if (height > 95 && Bookings.DaysViewSettings.EndHour - Bookings.DaysViewSettings.StartHour > 0)
        //         {
        //             double scrollheight = _employees.Length * 75 > Bookings.ActualWidth ? 15.0F : 0.0F;
        //             var header = _employees.Length > 1 ? 93.0F + scrollheight : 50.0F;
        //             Bookings.DaysViewSettings.TimeIntervalSize =
        //                 (height - header) / ((Bookings.DaysViewSettings.EndHour - Bookings.DaysViewSettings.StartHour) * 2.0F);
        //         }
        //     }
        //     
        //     // var scrollers = Bookings.FindVisualChildren<ScrollViewer>().Where(x => string.Equals(x.Name, "PART_TimeSlotScrollViewer")).ToArray();
        //     //     foreach (var scroll in scrollers)
        //     //         scroll.VerticalScrollBarVisibility = ScrollBarVisibility.Hidden;
        //
        // }

        private void Schedule_SizeChanged(object sender, SizeChangedEventArgs e)
        {
            //ResizeIntervals(e.NewSize.Height);

            ResizeColumns(e.NewSize.Width);
        }

        private void ResizeColumns(double width)
        {
            if (double.IsNaN(width) || !Bookings.FindVisualChildren<ScrollPanel>().Any())
                return;

            var maxcount = (int)width / 75;
            Bookings.DaysViewSettings.VisibleResourceCount = Math.Min(maxcount,
                _employees.Length * (Bookings.ViewType == SchedulerViewType.Day ? 1 : Bookings.ViewType == SchedulerViewType.WorkWeek ? 5 : 7));
            
            if (Bookings.ResourceCollection is ObservableCollection<SchedulerResource> resources)
            {
                var colwidth = GetResourceColumnWidth();
                foreach (var emp in _employees)
                {
                    var resource = resources.FirstOrDefault(x => String.Equals(x.Id?.ToString(), emp.ID.ToString()));
                    if (resource != null)
                    {
                        var comps = emp.Name.Split(' ');
                        var display = emp.Name;
                        if (colwidth < 75)
                            display = string.Format("{0}{1}", comps[0].Length > 0 ? comps[0][..1] : "",
                                comps.Length > 1 ? comps.Skip(1).First()[..1].ToUpper() : "");
                        else if (colwidth < 150)
                            display = string.Format("{0} {1}", comps.First(),
                                comps.Length > 1 ? comps.Skip(1).First()[..1].ToUpper() : "");
                        resource.Name = display;
                    }
                }
            }
        }

        private T CheckGrid<T>(ref T grid) where T : new()
        {
            if (grid == null)
                grid = new T();
            return grid;
        }

        private void ReloadColumns()
        {
            
            ResizeColumns(Bookings.ActualWidth);

            var colwidth = GetResourceColumnWidth();

            var resources = new List<SchedulerResource>();
            foreach (var emp in _employees)
            {
                var comps = emp.Name.Split(' ');
                var display = emp.Name;
                if (colwidth < 75)
                    display = CoreUtils.Codify(emp.Name);
                else if (colwidth < 150)
                    display = string.Format("{0} {1}", comps.Length > 0 ? comps.First() : "", comps.Length > 1 ? comps.Skip(1).First().Substring(0, 1).ToUpper() : "");
                resources.Add(new SchedulerResource { Name = display, Id = emp.ID.ToString() });
            }

            var sorted = new ObservableCollection<SchedulerResource>();
            foreach (var resource in resources.OrderBy(x => x.Name))
                sorted.Add(resource);
            try
            {
                Bookings.DaysViewSettings.ResourceHeaderSize = sorted.Count <= 1 ? 0 : 45;
            }
            catch (Exception e)
            {
                Logger.Send(LogType.Error, "", string.Format("*** Unknown Error: {0}\n{1}", e.Message, e.StackTrace));
            }

            //ResizeIntervals(Bookings.ActualHeight);
            try
            {
                Bookings.ResourceCollection = sorted;
            }
            catch (Exception e)
            {
                Logger.Send(LogType.Error, "", string.Format("*** Unknown Error: {0}\n{1}", e.Message, e.StackTrace));
            }

            bColumnsLoaded = true;
        }

        // private SchedulerResource GetCurrentResource()
        // {
        //     var p = Mouse.GetPosition(Bookings);
        //     var panels = Bookings.FindVisualChildren<ScrollViewer>().FirstOrDefault(x => string.Equals(x.Name, "PART_ViewHeaderScrollViewer"));
        //     var resource = (int)((p.X + panels.HorizontalOffset - (Bookings.DaysViewSettings.TimeRulerSize + 20F)) / GetResourceColumnWidth());
        //     return (Bookings.ResourceCollection as Collection<SchedulerResource>)[resource];
        // }
        //
        // private DateTime GetCurrentTime()
        // {
        //     var p = Mouse.GetPosition(Bookings);
        //     var hours = (p.Y - (_employees.Length > 1 ? 95.0F : 50.0F)) / (Bookings.DaysViewSettings.TimeIntervalSize * 2F) +
        //                 Bookings.DaysViewSettings.StartHour;
        //     var result = Bookings.SelectedDate.Value + TimeSpan.FromHours(hours);
        //     return result;
        // }

        private double GetResourceColumnWidth()
        {
            var colcount = Math.Max(1, _employees.Length);
            colcount = colcount * (Bookings.ViewType == SchedulerViewType.Day ? 1 : Bookings.ViewType == SchedulerViewType.Day ? 5 : 7);
            var colwidth = Bookings.ActualWidth / colcount;
            var minwidth = (Bookings.ActualWidth - (Bookings.DaysViewSettings.TimeRulerSize + 20F)) / Bookings.DaysViewSettings.VisibleResourceCount;
            return Math.Max(minwidth, colwidth);
        }
        

        private void Schedule_AppointmentEditorOpening(object sender, AppointmentEditorOpeningEventArgs e)
        {
            e.Cancel = true;
        }
        
        
        private Dictionary<CalendarMenuName, MenuItem> _menuitems = new Dictionary<CalendarMenuName, MenuItem>();

        public MenuItem? FindMenu(CalendarMenuName name)
        {
            _menuitems.TryGetValue(name, out MenuItem result);
            return result;
        }
        
        MenuItem CreateMenu<T>(ItemsControl menu, CalendarMenuName name, string header, Action<T?>? action = null, T? data = null) where T : class
        {
            var item = new MenuItem();
            item.Name = name.ToString();
            item.Header = header;
            if (action != null)
                item.Click += (o,args) => action(data);
            item.IsEnabled = data != null;
            menu.Items.Add(item);
            _menuitems[name] = item;
            return item;
        }
        
        private void Bookings_OnSchedulerContextMenuOpening(object? sender, SchedulerContextMenuOpeningEventArgs e)
        {

            
            e.ContextMenu.Items.Clear();
            if ((e.MenuType == SchedulerContextMenuType.Appointment) && (e.MenuInfo.Appointment is AssignmentAppointment appointment))
            {
                
                if (appointment.Model.MeetingID != Guid.Empty)
                    CreateMenu(e.ContextMenu, CalendarMenuName.Edit, "Edit Meeting", EditMeeting, appointment.Model);
                else
                {
                    CreateMenu(e.ContextMenu, CalendarMenuName.Edit, "Edit Assignment", EditAssignment, appointment.Model);
                    e.ContextMenu.Items.Add(new Separator());
                    CreateMenu(e.ContextMenu, CalendarMenuName.Copy, "Copy Assignment", CopyAssignment, appointment.Model);
                    e.ContextMenu.Items.Add(new Separator());
                    CreateMenu(e.ContextMenu, CalendarMenuName.Fill, "Fill Available Time", FillAssignment, appointment.Model);

                }
                e.ContextMenu.Items.Add(new Separator());
            
                CreateDigitalFormsMenu(e.ContextMenu, appointment);
                if (appointment.Model.MeetingID != Guid.Empty)
                    CreateMenu(e.ContextMenu, CalendarMenuName.Edit, "Delete Meeting", DeleteMeeting, appointment.Model);
                else
                    CreateMenu(e.ContextMenu, CalendarMenuName.Delete, "Delete Assignment", DeleteAssignment, appointment.Model);
                
                e.ContextMenu.Items.Add(new Separator());
                
                CreateMenu<object>(e.ContextMenu, CalendarMenuName.ZoomIn, "Zoom In", (data) => ZoomIn(), null);
                CreateMenu<object>(e.ContextMenu, CalendarMenuName.ZoomOut, "Zoom Out", (data) => ZoomOut(), null);
                CreateMenu<object>(e.ContextMenu, CalendarMenuName.ResetZoom, "Reset Zoom", (data) => ResetZoom(), null);
                
                CustomiseContextMenu?.Invoke(e.ContextMenu, new CalendarDataEventArgs<object>((e.MenuInfo.Appointment as ICalendarAppointment)?.Model));
                
            }
            else if (e.MenuType == SchedulerContextMenuType.TimeSlotCell)
            {
                if (Guid.TryParse(e.MenuInfo.Resource.Id?.ToString(), out Guid employeeid))
                {
                    var slot = new CalendarTimeSlot(employeeid, e.MenuInfo.DateTime.Value);
                    
                    var createmenu = new MenuItem() { Header = "Create.." };
                    CreateMenu(createmenu, CalendarMenuName.CreateNew, "New Assignment", (data) => CreateAssignment(slot), slot);
                    CreateMenu(createmenu, CalendarMenuName.CreateNew, "New Meeting", (data) => CreateMeeting(slot), slot);
                    e.ContextMenu.Items.Add(createmenu);

                    if (_copiedmodel != null)
                    {
                        e.ContextMenu.Items.Add(new Separator());
                        CreateMenu(e.ContextMenu, CalendarMenuName.Paste, "Paste Assignment", (data) => PasteAssignment(slot), slot);
                    }
                    e.ContextMenu.Items.Add(new Separator());
                    CreateMenu<object>(e.ContextMenu, CalendarMenuName.ZoomIn, "Zoom In", (data) => ZoomIn(), slot);
                    CreateMenu<object>(e.ContextMenu, CalendarMenuName.ZoomOut, "Zoom Out", (data) => ZoomOut(), slot);
                    CreateMenu<object>(e.ContextMenu, CalendarMenuName.ResetZoom, "Reset Zoom", (data) => ResetZoom(), slot);

                    CustomiseContextMenu?.Invoke(e.ContextMenu, new CalendarDataEventArgs<CalendarTimeSlot>(slot));
                }
            }
            
        }
        
        private static void CreateDigitalFormsMenu(ContextMenu menu, AssignmentAppointment appointment)
        {
            var digitalForms = new MenuItem { Header = "Digital Forms" };
            DynamicGridUtils.PopulateFormMenu<AssignmentForm, Assignment, AssignmentLink>(
                digitalForms,
                appointment.Model.ID,
                () => new Client<Assignment>().Load(new Filter<Assignment>(x => x.ID).IsEqualTo(appointment.Model.ID)).First(),
                false);

            menu.Items.Add(digitalForms);
            menu.Items.Add(new Separator());
        }

        
        public void CreateMeeting(CalendarTimeSlot slot)
        {
            if (slot == null)
            {
                MessageBox.Show("Please select an employee first!");
                return;
            }

            var meeting = new Meeting();
            meeting.Date = slot.Time.Date;

            meeting.Time.Start = AdjustStartTime(slot.Time.TimeOfDay);
            meeting.Time.Duration = TimeIntervalToTimeSpan(TimeInterval);
            meeting.Time.Finish = meeting.Time.Start + meeting.Time.Duration;
            
            ItemCreated?.Invoke(this, new CalendarDataEventArgs<Meeting>(meeting));
            
            var args = new CalendarHandledEventArgs<Meeting>(meeting);
            ItemEditing?.Invoke(this, args);
            
            if (args.Status == CalendarHandledStatus.Cancel)
                return;
            if (args.Status == CalendarHandledStatus.Handled)
            {
                Refresh();
                return;
            }
            CheckGrid(ref mg);
            var items = new[] { meeting };
            bool bOK = mg.EditItems(
                items, 
                (type) =>
                {
                    if (type == typeof(Assignment))
                        return LoadMeetingEmployees(meeting, slot.EmployeeID);
                    else if (type == typeof(MeetingItem))
                        return LoadMeetingItems();
                    return null;
                }, 
                true
            );
            if (bOK)
                Refresh();
        }

        private CoreTable LoadMeetingEmployees(Meeting meeting, Guid employeeid)
        {
            var result = new CoreTable();
            result.LoadColumns(typeof(Assignment));
            var assignment = new Assignment();
            assignment.EmployeeLink.ID = employeeid;
            var emp = new Client<Employee>().Load(new Filter<Employee>(x => x.ID).IsEqualTo(employeeid)).FirstOrDefault();
            if (emp != null)
                assignment.EmployeeLink.Synchronise(emp);
            result.LoadRows(new[] { assignment });
            return result;
        }

        private CoreTable LoadMeetingItems()
        {
            var result = new CoreTable();
            result.LoadColumns(typeof(MeetingItem));
            return result;
        }

        private void EditMeeting(AssignmentModel model)
        {
            if (model == null)
            {
                MessageBox.Show("Please select an entry first!");
                return;
            }

            CheckGrid(ref mg);
            
            var meeting = new Client<Meeting>().Query(
                new Filter<Meeting>(x => x.ID).IsEqualTo(model.MeetingID), 
                mg.LoadEditorColumns()
            ).Rows.FirstOrDefault()?.ToObject<Meeting>();
            if ((meeting != null) && (mg.EditItems(new[] { meeting })))
            {
                ItemChanged?.Invoke(this, new CalendarDataEventArgs<Meeting>(meeting));
                Refresh();
            }
        }
        
        private void DeleteMeeting(AssignmentModel model)
        {
            if (model == null)
            {
                MessageBox.Show("Please select an entry first!");
                return;
            }

            if (MessageBox.Show("Are you sure you wish to delete this meeting?", "Confirm Delete", MessageBoxButton.YesNo) != MessageBoxResult.Yes)
                return;
            
            var meeting = new Meeting { ID = model.MeetingID };
            new Client<Meeting>().Delete(meeting, "Meeting Deleted from Scheduler");
            ItemChanged?.Invoke(this, new CalendarDataEventArgs<Meeting>(meeting));
            Refresh();
            SelectionChanged?.Invoke(this, new CalendarDataEventArgs<Meeting>(null));
        }
        
        public Assignment CreateAssignment(CalendarTimeSlot slot)
        {
            if (slot == null)
            {
                MessageBox.Show("Please select an employee first!");
                return null;
            }

            var ass = new Assignment();
            ass.Date = slot.Time.Date;

            ass.Booked.Start = AdjustStartTime(slot.Time.TimeOfDay);
            ass.Booked.Duration = TimeIntervalToTimeSpan(TimeInterval);
            ass.Booked.Finish = ass.Booked.Start + ass.Booked.Duration;
            if ((AssignmentType == CalendarAssignmentType.Actual) || ((AssignmentType == CalendarAssignmentType.Automatic) && (ass.Date <= DateTime.Today)))
            {
                ass.Actual.Start = ass.Booked.Start;
                ass.Actual.Duration = ass.Booked.Duration;
                ass.Actual.Finish = ass.Actual.Start + ass.Actual.Duration;
            }
            
            ass.EmployeeLink.ID = slot.EmployeeID;

            ItemCreated?.Invoke(this, new CalendarDataEventArgs<Assignment>(ass));
            
            var args = new CalendarHandledEventArgs<Assignment>(ass);
            ItemEditing?.Invoke(this, args);
            if (args.Status == CalendarHandledStatus.Cancel)
                return null;
            
            if ((args.Status == CalendarHandledStatus.Handled) || CheckGrid(ref ag).EditItems(new[] { ass }))
            {
                UpdateAssignment(ass);
                _copiedmodel = null;
            }

            return ass;

        }

        private void FillAssignment(AssignmentModel model)
        {
            MessageBox.Show("Not Yet Implemented");
        }

        private void EditAssignment(AssignmentModel model)
        {
            if (model == null)
            {
                MessageBox.Show("Please select an entry first!");
                return;
            }

            var grid = CheckGrid(ref ag);


            var ass = new Client<Assignment>().Query(new Filter<Assignment>(x => x.ID).IsEqualTo(model.ID), grid.LoadEditorColumns())
                .ToObjects<Assignment>().FirstOrDefault();
            if (grid.EditItems(new[] { ass }))
            {
                ItemChanged?.Invoke(this, new CalendarDataEventArgs<Assignment>(ass));
                Refresh();
            }
            
        }

        private void DeleteAssignment(AssignmentModel model)
        {
            if (model == null)
            {
                MessageBox.Show("Please select an entry first!");
                return;
            }

            if (MessageBox.Show("Are you sure you wish to delete this assignment?", "Confirm Delete", MessageBoxButton.YesNo) != MessageBoxResult.Yes)
                return;
            
            var ass = new Assignment { ID = model.ID };
            new Client<Assignment>().Delete(ass, "Assignment Deleted from Scheduler");
            ItemChanged?.Invoke(this, new CalendarDataEventArgs<Assignment>(ass));
            Refresh();
            SelectionChanged?.Invoke(this, new CalendarDataEventArgs<Assignment>(null));

        }
        
        private AssignmentModel _copiedmodel;

        private void CopyAssignment(AssignmentModel model)
        {
            if (model == null)
            {
                MessageBox.Show("Please select an entry first!");
                return;
            }

            _copiedmodel = model;
        }

        private Assignment PasteAssignment(CalendarTimeSlot slot)
        {
            if (slot == null)
            {
                MessageBox.Show("Please select an employee first!");
                return null;
            }
            
            var ass = _assignments.FirstOrDefault(a => a.ID == _copiedmodel.ID)?.Row?.ToObject<Assignment>();
            if (ass == null)
            {
                MessageBox.Show("Cannot find copied entry!");
                return null;
            }               
            
            ass.Date = SelectedDate.Date;
            ass.ID = Guid.Empty;
            ass.Number = 0;
            ass.CommitChanges();
            
            ass.Booked.Start = AdjustStartTime(slot.Time.TimeOfDay);
            ass.Booked.Duration = TimeIntervalToTimeSpan(TimeInterval);
            ass.Booked.Finish = ass.Booked.Start + ass.Booked.Duration;    
            if ((AssignmentType == CalendarAssignmentType.Actual) || ((AssignmentType == CalendarAssignmentType.Automatic) && (ass.Date <= DateTime.Today)))
            {
                ass.Actual.Start = ass.Booked.Start;
                ass.Actual.Duration = ass.Booked.Duration;
                ass.Actual.Finish = ass.Actual.Start + ass.Actual.Duration;
            }
            
            ass.EmployeeLink.ID = slot.EmployeeID;

            new Client<Assignment>().Save(ass, "");
            UpdateAssignment(ass);
            _copiedmodel = null;
            return ass;

        }
        
        private void Bookings_OnAppointmentTapped(object? sender, AppointmentTappedArgs e)
        {
            //if (e.Appointment is AssignmentModel model) 
            if (e.Appointment is AssignmentAppointment appointment) 
            {
                
                ICalendarDataEventArgs args = new CalendarDataEventArgs<Assignment>(
                    appointment.Model.Row?.ToObject<Assignment>()
                );
                SelectionChanged?.Invoke(this, args);
            }
            else
                SelectionChanged?.Invoke(this, new CalendarDataEventArgs<Assignment>(null));
               
        }


        private void Calendar_OnSizeChanged(object sender, SizeChangedEventArgs e)
        {
            if (double.IsNaN(this.ActualHeight) || (this.ActualHeight == 0))
                return;
            UpdateZoom();
        }
    }
}