| | | 1 | | using ArturRios.Output; |
| | | 2 | | |
| | | 3 | | namespace ArturRios.Util.FlowControl; |
| | | 4 | | |
| | | 5 | | /// <summary> |
| | | 6 | | /// A fluent helper to evaluate multiple boolean conditions and aggregate failures. |
| | | 7 | | /// </summary> |
| | | 8 | | /// <remarks> |
| | | 9 | | /// Use <see cref="True"/> or <see cref="False"/> to set the result of an expression and chain <see cref="FailsWith"/> t |
| | | 10 | | /// After building all conditions call <see cref="ThrowIfNotSatisfied"/> or inspect <see cref="IsSatisfied"/> / <see cre |
| | | 11 | | /// Failures are reported in the order they were recorded, and two conditions that fail with the same |
| | | 12 | | /// message are reported twice: the count reflects conditions, not distinct wordings. |
| | | 13 | | /// </remarks> |
| | | 14 | | public class Condition |
| | | 15 | | { |
| | | 16 | | /// <summary> |
| | | 17 | | /// The error <see cref="ToProcessOutput"/> reports for a condition that failed with an empty or |
| | | 18 | | /// whitespace message. |
| | | 19 | | /// </summary> |
| | | 20 | | public const string BlankFailureMessage = "A condition was not satisfied."; |
| | | 21 | | |
| | | 22 | | private readonly List<string> _failedConditions = []; |
| | | 23 | | private bool? _expression; |
| | | 24 | | |
| | | 25 | | /// <summary> |
| | | 26 | | /// Creates a new <see cref="Condition"/> instance. Syntactic sugar for <c>new Condition()</c>. |
| | | 27 | | /// </summary> |
| | | 28 | | public static Condition Create => new(); |
| | | 29 | | |
| | | 30 | | /// <summary> |
| | | 31 | | /// Gets an array of all failure messages collected by <see cref="FailsWith"/>, in the order they failed. |
| | | 32 | | /// </summary> |
| | | 33 | | public string[] FailedConditions => [.. _failedConditions]; |
| | | 34 | | |
| | | 35 | | /// <summary> |
| | | 36 | | /// Indicates whether all evaluated conditions have succeeded (i.e. there are no failures). |
| | | 37 | | /// </summary> |
| | | 38 | | public bool IsSatisfied => _failedConditions.Count == 0; |
| | | 39 | | |
| | | 40 | | /// <summary> |
| | | 41 | | /// Sets the current expression result to <paramref name="expression"/>. |
| | | 42 | | /// </summary> |
| | | 43 | | /// <param name="expression">The boolean value representing the success of the condition.</param> |
| | | 44 | | /// <returns>The current <see cref="Condition"/> for fluent chaining.</returns> |
| | | 45 | | public Condition True(bool expression) |
| | | 46 | | { |
| | | 47 | | _expression = expression; |
| | | 48 | | |
| | | 49 | | return this; |
| | | 50 | | } |
| | | 51 | | |
| | | 52 | | /// <summary> |
| | | 53 | | /// Sets the current expression result to the negated value of <paramref name="expression"/>. |
| | | 54 | | /// </summary> |
| | | 55 | | /// <param name="expression">The boolean to negate.</param> |
| | | 56 | | /// <returns>The current <see cref="Condition"/> for fluent chaining.</returns> |
| | | 57 | | public Condition False(bool expression) |
| | | 58 | | { |
| | | 59 | | _expression = !expression; |
| | | 60 | | |
| | | 61 | | return this; |
| | | 62 | | } |
| | | 63 | | |
| | | 64 | | /// <summary> |
| | | 65 | | /// Adds an error message if the most recently set expression evaluated to <c>false</c>. |
| | | 66 | | /// </summary> |
| | | 67 | | /// <param name="error">The error message describing the failure.</param> |
| | | 68 | | /// <returns>The current <see cref="Condition"/> for fluent chaining.</returns> |
| | | 69 | | /// <exception cref="ArgumentNullException"><paramref name="error"/> is <c>null</c>.</exception> |
| | | 70 | | /// <exception cref="InvalidOperationException"> |
| | | 71 | | /// No <see cref="True"/> or <see cref="False"/> call precedes this one. Recording a failure for an |
| | | 72 | | /// expression that was never evaluated would silently invent one. |
| | | 73 | | /// </exception> |
| | | 74 | | public Condition FailsWith(string error) |
| | | 75 | | { |
| | | 76 | | ArgumentNullException.ThrowIfNull(error); |
| | | 77 | | |
| | | 78 | | if (_expression is null) |
| | | 79 | | { |
| | | 80 | | throw new InvalidOperationException( |
| | | 81 | | $"{nameof(FailsWith)} must follow a call to {nameof(True)} or {nameof(False)}."); |
| | | 82 | | } |
| | | 83 | | |
| | | 84 | | if (!_expression.Value) |
| | | 85 | | { |
| | | 86 | | _failedConditions.Add(error); |
| | | 87 | | } |
| | | 88 | | |
| | | 89 | | return this; |
| | | 90 | | } |
| | | 91 | | |
| | | 92 | | /// <summary> |
| | | 93 | | /// Throws a <see cref="ConditionFailedException"/> if any condition failed. |
| | | 94 | | /// </summary> |
| | | 95 | | /// <exception cref="ConditionFailedException">Thrown when <see cref="IsSatisfied"/> is false.</exception> |
| | | 96 | | public void ThrowIfNotSatisfied() |
| | | 97 | | { |
| | | 98 | | if (IsSatisfied) |
| | | 99 | | { |
| | | 100 | | return; |
| | | 101 | | } |
| | | 102 | | |
| | | 103 | | throw new ConditionFailedException(FailedConditions); |
| | | 104 | | } |
| | | 105 | | |
| | | 106 | | /// <summary> |
| | | 107 | | /// Converts the condition failures into a <see cref="ProcessOutput"/> instance. |
| | | 108 | | /// </summary> |
| | | 109 | | /// <returns> |
| | | 110 | | /// A <see cref="ProcessOutput"/> carrying one error per failed condition, in order, when the condition is |
| | | 111 | | /// not satisfied; its <see cref="ProcessOutput.Success"/> always agrees with <see cref="IsSatisfied"/>. |
| | | 112 | | /// </returns> |
| | | 113 | | /// <remarks> |
| | | 114 | | /// <see cref="ProcessOutput"/> drops empty and whitespace errors, so a condition that failed with such a |
| | | 115 | | /// message used to convert into a successful output. A blank message is therefore reported as |
| | | 116 | | /// <see cref="BlankFailureMessage"/> instead. |
| | | 117 | | /// </remarks> |
| | | 118 | | public ProcessOutput ToProcessOutput() |
| | | 119 | | { |
| | | 120 | | var output = new ProcessOutput(); |
| | | 121 | | |
| | | 122 | | output.AddErrors(_failedConditions.Select(error => |
| | | 123 | | string.IsNullOrWhiteSpace(error) ? BlankFailureMessage : error)); |
| | | 124 | | |
| | | 125 | | return output; |
| | | 126 | | } |
| | | 127 | | } |
| | | 128 | | |
| | | 129 | | /// <summary> |
| | | 130 | | /// Exception raised when one or more conditions fail in a <see cref="Condition"/> chain. |
| | | 131 | | /// </summary> |
| | | 132 | | /// <param name="errors">The set of failure messages collected.</param> |
| | | 133 | | public class ConditionFailedException(string[] errors) |
| | 1 | 134 | | : Exception($"A total of {errors.Length} conditions failed: {string.Join("; ", errors)}") |
| | | 135 | | { |
| | | 136 | | /// <summary> |
| | | 137 | | /// The failure messages that caused this exception, in the order they failed. |
| | | 138 | | /// </summary> |
| | 2 | 139 | | public string[] Errors { get; } = errors; |
| | | 140 | | } |