BeWoPlaner/BeWo/SchulbegleitenderDienst/ViewModel/AbsenceTimeEditViewModel.cs

using System;
using System.ComponentModel;
using System.Windows;
using BeWo.Core.Commands;
using BS.Shared.Extensions;
using DevExpress.Mvvm;

namespace BeWo.SchulbegleitenderDienst.ViewModel
{
    public class AbsenceTimeEditViewModel : ViewModelBase, IDataErrorInfo
    {
        private bool _IsAllDay;
        private DateTime _StartDate;
        private DateTime? _EndDate;

        public ButtonClickCommand ValidateButtonCommand { get; }

        public Action<TagesansichtVM> SaveChanges { get; set; }

        private readonly TagesansichtVM _TagesansichtVM;

        public bool IsAllDay
        {
            get => _IsAllDay;

            set
            {
                _IsAllDay = value;

                if (_IsAllDay)
                {
                    _StartDate = _StartDate.MergeDatesByDate(StartDate.Date);

                    _EndDate = _EndDate?.MergeDatesByDate(_EndDate.Value.Date);
                }
                else if(_TagesansichtVM?.StartDate != null)
                {
                    _StartDate = _StartDate.MergeDatesByDate(_TagesansichtVM.StartDate.Value);

                    _EndDate = _TagesansichtVM?.EndDate != null ? _EndDate?.MergeDatesByDate(_TagesansichtVM.EndDate.Value) : null;
                }

                RaisePropertiesChanged();
            }
        }

        public string StartTime
        {
            get => $"{_StartDate:HH:mm}";

            set
            {
                if (DateTime.TryParse($"{DateTime.Today:yyyy-MM-dd} {value ?? "00:00"}", out var parsedPrototypeStartDate))
                {
                    _StartDate = _StartDate.MergeDatesByDate(parsedPrototypeStartDate);
                    RaisePropertiesChanged();
                }
            }
        }

        public string EndTime
        {
            get => $"{(_EndDate.HasValue ? _EndDate.Value.ToString("HH:mm") : string.Empty)}";

            set
            {
                if (DateTime.TryParse($"{DateTime.Today:yyyy-MM-dd} {value ?? "00:00"}", out var parsedPrototypeStartDate))
                {
                    _EndDate = _EndDate?.MergeDatesByDate(parsedPrototypeStartDate);

                    RaisePropertiesChanged();
                }
            }
        }

        public DateTime StartDate
        {
            get => _StartDate;

            set
            {
                if (!Equals(_StartDate, value))
                {
                    _StartDate = value;
                    SetIsAllDay();
                    RaisePropertiesChanged();
                }
            }
        }

        public DateTime? EndDate
        {
            get => _EndDate;

            set
            {
                if (!Equals(_EndDate, value))
                {
                    _EndDate = value;
                    SetIsAllDay();
                    RaisePropertiesChanged();
                }
            }
        }

        private void SetIsAllDay()
        {
            IsAllDay = _StartDate.Hour == 0 && _StartDate.Minute == 0 && (_EndDate == null || _EndDate.Value.Hour == 0 && _EndDate.Value.Minute == 0);
        }

        public AbsenceTimeEditViewModel() { }

        public AbsenceTimeEditViewModel(DateTime startDate, DateTime? endDate, TagesansichtVM tagesansichtVM, Action<TagesansichtVM> saveChanges)
        {
            ValidateButtonCommand = new ButtonClickCommand(ValidateInput);

            _TagesansichtVM = tagesansichtVM;

            SaveChanges = saveChanges;

            StartDate = startDate;
            EndDate = endDate;

            IsAllDay = startDate.Hour == 0 && startDate.Minute == 0 && (endDate == null || endDate.Value.Hour == 0 && endDate.Value.Minute == 0);
        }

        string IDataErrorInfo.Error
        {
            get
            {
                var me = (IDataErrorInfo) this;
                var error = me[GetPropertyName(() => StartDate)] +
                            me[GetPropertyName(() => EndDate)];

                return error;
            }
        }

        string IDataErrorInfo.this[string columnName]
        {
            get
            {
                if (EndDate != null && EndDate.Value < StartDate)
                {
                    return "Das Startdatum muss vor dem Enddatum liegen.";
                }

                return null;
            }
        }

        public void ValidateInput()
        {
            var error = ((IDataErrorInfo) this).Error;

            if (!string.IsNullOrEmpty(error))
            {
                MessageBox.Show("Das Startdatum muss vor dem Enddatum liegen.", "Ungültige Datumsangaben", MessageBoxButton.OK, MessageBoxImage.Error);
                RaisePropertiesChanged();
            }
            else
            {
                _TagesansichtVM.Absencetime.Start = StartDate;
                _TagesansichtVM.Absencetime.End = EndDate;

                SaveChanges?.Invoke(_TagesansichtVM);
            }
        }
    }
}