FModel/FModel/ViewModels/SearchViewModel.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text.RegularExpressions;
using System.Windows.Data;
using FModel.Framework;

namespace FModel.ViewModels;

public class SearchViewModel : ViewModel
{
    private string _filterText;
    public string FilterText
    {
        get => _filterText;
        set => SetProperty(ref _filterText, value);
    }

    private bool _hasRegexEnabled;
    public bool HasRegexEnabled
    {
        get => _hasRegexEnabled;
        set => SetProperty(ref _hasRegexEnabled, value);
    }

    private bool _hasMatchCaseEnabled;
    public bool HasMatchCaseEnabled
    {
        get => _hasMatchCaseEnabled;
        set => SetProperty(ref _hasMatchCaseEnabled, value);
    }

    public int ResultsCount => SearchResults?.Count ?? 0;
    public RangeObservableCollection<AssetItem> SearchResults { get; }
    public ICollectionView SearchResultsView { get; }

    public SearchViewModel()
    {
        SearchResults = new RangeObservableCollection<AssetItem>();
        SearchResultsView = new ListCollectionView(SearchResults);
    }

    public void RefreshFilter()
    {
        if (SearchResultsView.Filter == null)
            SearchResultsView.Filter = e => ItemFilter(e, FilterText.Trim().Split(' '));
        else
            SearchResultsView.Refresh();
    }

    private bool ItemFilter(object item, IEnumerable<string> filters)
    {
        if (item is not AssetItem assetItem)
            return true;

        if (!HasRegexEnabled)
            return filters.All(x => assetItem.FullPath.Contains(x, HasMatchCaseEnabled ? StringComparison.Ordinal : StringComparison.OrdinalIgnoreCase));

        var o = RegexOptions.None;
        if (!HasMatchCaseEnabled) o |= RegexOptions.IgnoreCase;
        return new Regex(FilterText, o).Match(assetItem.FullPath).Success;
    }
}