using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Windows.Data;
using System.Windows.Input;

namespace XLAB2
{
    internal sealed class SelectInstrumentTypeWindowViewModel : ObservableObject
    {
        private string _searchText;
        private AvailableInstrumentItem _selectedType;
        private string _serialNumbersText;
        private string _statusText;

        public SelectInstrumentTypeWindowViewModel(string customerName, IReadOnlyList<AvailableInstrumentItem> instrumentTypes)
        {
            CustomerName = customerName ?? string.Empty;
            InstrumentTypes = new ObservableCollection<AvailableInstrumentItem>(instrumentTypes ?? new List<AvailableInstrumentItem>());
            InstrumentTypesView = CollectionViewSource.GetDefaultView(InstrumentTypes);
            InstrumentTypesView.Filter = FilterTypes;

            ConfirmCommand = new RelayCommand(Confirm, CanConfirm);
            CancelCommand = new RelayCommand(Cancel);
            UpdateStatus();
        }

        public event EventHandler<bool?> CloseRequested;

        public ICommand CancelCommand { get; private set; }

        public ICommand ConfirmCommand { get; private set; }

        public string CustomerName { get; private set; }

        public ObservableCollection<AvailableInstrumentItem> InstrumentTypes { get; private set; }

        public ICollectionView InstrumentTypesView { get; private set; }

        public string SearchText
        {
            get { return _searchText; }
            set
            {
                if (SetProperty(ref _searchText, value))
                {
                    InstrumentTypesView.Refresh();
                    UpdateStatus();
                }
            }
        }

        public AvailableInstrumentItem SelectedType
        {
            get { return _selectedType; }
            set
            {
                if (SetProperty(ref _selectedType, value))
                {
                    ((RelayCommand)ConfirmCommand).RaiseCanExecuteChanged();
                    UpdateStatus();
                }
            }
        }

        public string SerialNumbersText
        {
            get { return _serialNumbersText; }
            set
            {
                if (SetProperty(ref _serialNumbersText, value))
                {
                    ((RelayCommand)ConfirmCommand).RaiseCanExecuteChanged();
                    UpdateStatus();
                }
            }
        }

        public string StatusText
        {
            get { return _statusText; }
            private set { SetProperty(ref _statusText, value); }
        }

        public InstrumentTypeSelectionResult GetResult()
        {
            var serialNumbers = ParseSerialNumbers(SerialNumbersText);
            return SelectedType == null
                ? null
                : new InstrumentTypeSelectionResult
                {
                    TypeItem = SelectedType,
                    SerialNumbers = serialNumbers
                };
        }

        private void Cancel(object parameter)
        {
            RaiseCloseRequested(false);
        }

        private bool CanConfirm(object parameter)
        {
            return SelectedType != null
                   && ParseSerialNumbers(SerialNumbersText).Count > 0;
        }

        private void Confirm(object parameter)
        {
            RaiseCloseRequested(true);
        }

        private bool FilterTypes(object item)
        {
            var instrumentType = item as AvailableInstrumentItem;
            if (instrumentType == null)
            {
                return false;
            }

            if (string.IsNullOrWhiteSpace(SearchText))
            {
                return true;
            }

            return Contains(instrumentType.RegistryNumber, SearchText)
                   || Contains(instrumentType.InstrumentName, SearchText)
                   || Contains(instrumentType.InstrumentType, SearchText)
                   || Contains(instrumentType.RangeText, SearchText)
                   || Contains(instrumentType.AccuracyText, SearchText)
                   || Contains(instrumentType.MeasurementArea, SearchText);
        }

        private static bool Contains(string source, string searchText)
        {
            return !string.IsNullOrWhiteSpace(source)
                   && source.IndexOf(searchText, StringComparison.OrdinalIgnoreCase) >= 0;
        }

        private static List<string> ParseSerialNumbers(string value)
        {
            var serialNumbers = new List<string>();
            var unique = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
            if (string.IsNullOrWhiteSpace(value))
            {
                return serialNumbers;
            }

            var separators = new[] { '\r', '\n', '\t', ',', ';' };
            foreach (var token in value.Split(separators, StringSplitOptions.RemoveEmptyEntries))
            {
                var serialNumber = token.Trim();
                if (serialNumber.Length == 0 || !unique.Add(serialNumber))
                {
                    continue;
                }

                serialNumbers.Add(serialNumber);
            }

            return serialNumbers;
        }

        private void RaiseCloseRequested(bool? dialogResult)
        {
            var handler = CloseRequested;
            if (handler != null)
            {
                handler(this, dialogResult);
            }
        }

        private void UpdateStatus()
        {
            var visibleCount = InstrumentTypesView.Cast<object>().Count();
            var serialCount = ParseSerialNumbers(SerialNumbersText).Count;
            StatusText = string.Format(
                "Всего типов: {0}. По фильтру: {1}. Выбран тип: {2}. Уникальных зав. №: {3}.",
                InstrumentTypes.Count,
                visibleCount,
                SelectedType == null ? "нет" : "да",
                serialCount);
        }
    }
}