| | | 1 | | // ----------------------------------------------------------------------- |
| | | 2 | | // <copyright file="CollectionStatistics.cs" company="Stéphane ANDRE"> |
| | | 3 | | // Copyright (c) Stéphane ANDRE. All rights reserved. |
| | | 4 | | // </copyright> |
| | | 5 | | // ----------------------------------------------------------------------- |
| | | 6 | | |
| | | 7 | | using System; |
| | | 8 | | using System.Collections.Generic; |
| | | 9 | | using System.ComponentModel; |
| | | 10 | | using System.Linq; |
| | | 11 | | using System.Reactive.Disposables; |
| | | 12 | | |
| | | 13 | | namespace MyNet.Observable.Collections.Statistics; |
| | | 14 | | |
| | | 15 | | /// <summary> |
| | | 16 | | /// Reactive view statistics over the filtered items of an <see cref="ExtendedCollection{T}"/>. |
| | | 17 | | /// </summary> |
| | | 18 | | /// <typeparam name="T">The item type.</typeparam> |
| | | 19 | | /// <typeparam name="TValue">The aggregated value type.</typeparam> |
| | | 20 | | public sealed class CollectionStatistics<T, TValue> : ObservableObject |
| | | 21 | | where T : notnull |
| | | 22 | | { |
| | | 23 | | private readonly ExtendedCollection<T> _collection; |
| | | 24 | | private readonly Func<T, TValue> _valueSelector; |
| | | 25 | | private readonly IStatisticsComputer<TValue> _computer; |
| | | 26 | | private double _filteredPercentage; |
| | | 27 | | private TValue _sum = default!; |
| | | 28 | | private TValue _average = default!; |
| | | 29 | | private TValue _min = default!; |
| | | 30 | | private TValue _max = default!; |
| | | 31 | | |
| | | 32 | | private CollectionStatistics(ExtendedCollection<T> collection, Func<T, TValue> valueSelector, IStatisticsComputer<TV |
| | | 33 | | { |
| | | 34 | | _collection = collection ?? throw new ArgumentNullException(nameof(collection)); |
| | | 35 | | _valueSelector = valueSelector ?? throw new ArgumentNullException(nameof(valueSelector)); |
| | | 36 | | _computer = computer; |
| | | 37 | | |
| | | 38 | | Disposables.Add(_collection.Connect().Subscribe(_ => RecalculateValues())); |
| | | 39 | | _collection.PropertyChanged += OnCollectionPropertyChanged; |
| | | 40 | | Disposables.Add(Disposable.Create(() => _collection.PropertyChanged -= OnCollectionPropertyChanged)); |
| | | 41 | | |
| | | 42 | | UpdateFilteredPercentage(); |
| | | 43 | | RecalculateValues(); |
| | | 44 | | } |
| | | 45 | | |
| | | 46 | | /// <summary> |
| | | 47 | | /// Gets the ratio of filtered items to source items, or <c>0</c> when the source is empty. |
| | | 48 | | /// </summary> |
| | | 49 | | public double FilteredPercentage => _filteredPercentage; |
| | | 50 | | |
| | | 51 | | /// <summary> |
| | | 52 | | /// Gets the sum of values across filtered items. |
| | | 53 | | /// </summary> |
| | | 54 | | public TValue Sum => _sum; |
| | | 55 | | |
| | | 56 | | /// <summary> |
| | | 57 | | /// Gets the average of values across filtered items. |
| | | 58 | | /// </summary> |
| | | 59 | | public TValue Average => _average; |
| | | 60 | | |
| | | 61 | | /// <summary> |
| | | 62 | | /// Gets the minimum value across filtered items. |
| | | 63 | | /// </summary> |
| | | 64 | | public TValue Min => _min; |
| | | 65 | | |
| | | 66 | | /// <summary> |
| | | 67 | | /// Gets the maximum value across filtered items. |
| | | 68 | | /// </summary> |
| | | 69 | | public TValue Max => _max; |
| | | 70 | | |
| | | 71 | | /// <summary> |
| | | 72 | | /// Creates a <see cref="CollectionStatistics{T, TType}"/> instance to track view metrics and numeric aggregates (su |
| | | 73 | | /// </summary> |
| | | 74 | | /// <param name="collection">The collection whose filtered view is aggregated.</param> |
| | | 75 | | /// <param name="valueSelector">Selects the numeric value for each item.</param> |
| | | 76 | | /// <returns>A <see cref="CollectionStatistics{T, TType}"/> instance.</returns> |
| | | 77 | | internal static CollectionStatistics<T, double> ForDouble(ExtendedCollection<T> collection, Func<T, double> valueSel |
| | | 78 | | new(collection, valueSelector, DoubleStatisticsComputer.Instance); |
| | | 79 | | |
| | | 80 | | /// <summary> |
| | | 81 | | /// Creates a <see cref="CollectionStatistics{T, TType}"/> instance to track view metrics and <see cref="TimeSpan"/> |
| | | 82 | | /// </summary> |
| | | 83 | | /// <param name="collection">The collection whose filtered view is aggregated.</param> |
| | | 84 | | /// <param name="valueSelector">Selects the duration for each item.</param> |
| | | 85 | | /// <returns>A <see cref="CollectionStatistics{T, TType}"/> instance.</returns> |
| | | 86 | | internal static CollectionStatistics<T, TimeSpan> ForTimeSpan(ExtendedCollection<T> collection, Func<T, TimeSpan> va |
| | | 87 | | new(collection, valueSelector, TimeSpanStatisticsComputer.Instance); |
| | | 88 | | |
| | | 89 | | /// <summary> |
| | | 90 | | /// Handles property changes of the underlying collection to update the filtered percentage and recalculate aggregat |
| | | 91 | | /// </summary> |
| | | 92 | | /// <param name="sender">The source of the event.</param> |
| | | 93 | | /// <param name="e">The <see cref="PropertyChangedEventArgs"/> instance containing the event data.</param> |
| | | 94 | | private void OnCollectionPropertyChanged(object? sender, PropertyChangedEventArgs e) |
| | | 95 | | { |
| | | 96 | | if (e.PropertyName is nameof(ExtendedCollection<>.Count) or nameof(ExtendedCollection<>.SourceCount)) |
| | | 97 | | UpdateFilteredPercentage(); |
| | | 98 | | |
| | | 99 | | if (e.PropertyName is nameof(ExtendedCollection<>.Count)) |
| | | 100 | | RecalculateValues(); |
| | | 101 | | } |
| | | 102 | | |
| | | 103 | | /// <summary> |
| | | 104 | | /// Updates the filtered percentage based on the current count of filtered items and the total source count. If the |
| | | 105 | | /// </summary> |
| | | 106 | | private void UpdateFilteredPercentage() |
| | | 107 | | { |
| | | 108 | | var value = _collection.SourceCount == 0 |
| | | 109 | | ? 0 |
| | | 110 | | : (double)_collection.Count / _collection.SourceCount; |
| | | 111 | | |
| | | 112 | | SetProperty(ref _filteredPercentage, value, nameof(FilteredPercentage)); |
| | | 113 | | } |
| | | 114 | | |
| | | 115 | | /// <summary> |
| | | 116 | | /// Recalculates the sum, average, minimum, and maximum values across the filtered items in the collection. It retri |
| | | 117 | | /// </summary> |
| | | 118 | | private void RecalculateValues() |
| | | 119 | | { |
| | | 120 | | var values = _collection.Items.Select(_valueSelector).ToList(); |
| | | 121 | | var (sum, average, min, max) = values.Count == 0 |
| | | 122 | | ? _computer.Empty |
| | | 123 | | : _computer.Compute(values); |
| | | 124 | | |
| | | 125 | | SetProperty(ref _sum, sum, nameof(Sum)); |
| | | 126 | | SetProperty(ref _average, average, nameof(Average)); |
| | | 127 | | SetProperty(ref _min, min, nameof(Min)); |
| | | 128 | | SetProperty(ref _max, max, nameof(Max)); |
| | | 129 | | } |
| | | 130 | | } |
| | | 131 | | |
| | | 132 | | /// <summary> |
| | | 133 | | /// Defines an interface for computing statistics such as sum, average, minimum, and maximum values from a list of value |
| | | 134 | | /// </summary> |
| | | 135 | | /// <typeparam name="TValue">The type of value for which statistics are computed.</typeparam> |
| | | 136 | | internal interface IStatisticsComputer<TValue> |
| | | 137 | | { |
| | | 138 | | /// <summary> |
| | | 139 | | /// Gets the default statistics values for an empty list of values. This property returns a tuple containing the sum |
| | | 140 | | /// </summary> |
| | | 141 | | (TValue Sum, TValue Average, TValue Min, TValue Max) Empty { get; } |
| | | 142 | | |
| | | 143 | | /// <summary> |
| | | 144 | | /// Computes the sum, average, minimum, and maximum values from the provided list of values. This method takes a rea |
| | | 145 | | /// </summary> |
| | | 146 | | /// <param name="values">The list of values for which to compute statistics.</param> |
| | | 147 | | /// <returns>A tuple containing the computed sum, average, minimum, and maximum values.</returns> |
| | | 148 | | (TValue Sum, TValue Average, TValue Min, TValue Max) Compute(IReadOnlyList<TValue> values); |
| | | 149 | | } |
| | | 150 | | |
| | | 151 | | /// <summary> |
| | | 152 | | /// Provides an implementation of the <see cref="IStatisticsComputer{TValue}"/> interface for computing statistics on do |
| | | 153 | | /// </summary> |
| | | 154 | | internal sealed class DoubleStatisticsComputer : IStatisticsComputer<double> |
| | | 155 | | { |
| | | 156 | | /// <summary> |
| | | 157 | | /// Gets a singleton instance of the <see cref="DoubleStatisticsComputer"/> class. This instance can be used to comp |
| | | 158 | | /// </summary> |
| | | 159 | | public static DoubleStatisticsComputer Instance { get; } = new(); |
| | | 160 | | |
| | | 161 | | /// <inheritdoc/> |
| | | 162 | | public (double Sum, double Average, double Min, double Max) Empty => |
| | | 163 | | (0, double.NaN, double.NaN, double.NaN); |
| | | 164 | | |
| | | 165 | | /// <inheritdoc/> |
| | | 166 | | public (double Sum, double Average, double Min, double Max) Compute(IReadOnlyList<double> values) => |
| | | 167 | | (values.Sum(), values.Average(), values.Min(), values.Max()); |
| | | 168 | | } |
| | | 169 | | |
| | | 170 | | /// <summary> |
| | | 171 | | /// Provides an implementation of the <see cref="IStatisticsComputer{TValue}"/> interface for computing statistics on <s |
| | | 172 | | /// </summary> |
| | | 173 | | internal sealed class TimeSpanStatisticsComputer : IStatisticsComputer<TimeSpan> |
| | | 174 | | { |
| | | 175 | | /// <summary> |
| | | 176 | | /// Gets a singleton instance of the <see cref="TimeSpanStatisticsComputer"/> class. This instance can be used to co |
| | | 177 | | /// </summary> |
| | 3 | 178 | | public static TimeSpanStatisticsComputer Instance { get; } = new(); |
| | | 179 | | |
| | | 180 | | /// <inheritdoc/> |
| | | 181 | | public (TimeSpan Sum, TimeSpan Average, TimeSpan Min, TimeSpan Max) Empty => |
| | 0 | 182 | | (TimeSpan.Zero, TimeSpan.Zero, TimeSpan.Zero, TimeSpan.Zero); |
| | | 183 | | |
| | | 184 | | /// <inheritdoc/> |
| | | 185 | | public (TimeSpan Sum, TimeSpan Average, TimeSpan Min, TimeSpan Max) Compute(IReadOnlyList<TimeSpan> values) |
| | | 186 | | { |
| | 6 | 187 | | var ticks = values.Select(v => v.Ticks).ToList(); |
| | 6 | 188 | | return ( |
| | 6 | 189 | | new(ticks.Sum()), |
| | 6 | 190 | | new((long)ticks.Average()), |
| | 6 | 191 | | new(ticks.Min()), |
| | 6 | 192 | | new(ticks.Max())); |
| | | 193 | | } |
| | | 194 | | } |
| | | 195 | | |