LabelQueryExtensions.cs

using AngleSharp.Dom;
using Bunit.Labels.Strategies;
using Bunit.Web.AngleSharp;

namespace Bunit;

/// <summary>
/// Extension methods for querying <see cref="IRenderedComponent{TComponent}" /> by Label
/// </summary>
public static class LabelQueryExtensions
{
	private static readonly IReadOnlyList<ILabelTextQueryStrategy> LabelTextQueryStrategies =
	[
		// This is intentionally in the order of most likely to minimize strategies tried to find the label
		new LabelTextUsingForAttributeStrategy(),
		new LabelTextUsingAriaLabelStrategy(),
		new LabelTextUsingWrappedElementStrategy(),
		new LabelTextUsingAriaLabelledByStrategy(),
	];

	/// <summary>
	/// Returns the first element (i.e. an input, select, textarea, etc. element) associated with the given label text.
	/// </summary>
	/// <param name="renderedComponent">The rendered fragment to search.</param>
	/// <param name="labelText">The text of the label to search (i.e. the InnerText of the Label, such as "First Name" for a `<label>First Name</label>`)</param>
	/// <param name="configureOptions">Method used to override the default behavior of FindByLabelText.</param>
	public static IElement FindByLabelText(this IRenderedComponent<IComponent> renderedComponent, string labelText, Action<ByLabelTextOptions>? configureOptions = null)
	{
		var options = ByLabelTextOptions.Default;
		if (configureOptions is not null)
		{
			options = options with { };
			configureOptions.Invoke(options);
		}

		return FindByLabelTextInternal(renderedComponent, labelText, options) ?? throw new LabelNotFoundException(labelText);
	}

	/// <summary>
	/// Returns all elements (i.e. input, select, textarea, etc. elements) associated with the given label text.
	/// </summary>
	/// <param name="renderedComponent">The rendered fragment to search.</param>
	/// <param name="labelText">The text of the label to search (i.e. the InnerText of the Label, such as "First Name" for a `<label>First Name</label>`)</param>
	/// <param name="configureOptions">Method used to override the default behavior of FindAllByLabelText.</param>
	/// <returns>A read-only collection of elements matching the label text. Returns an empty collection if no matches are found.</returns>
	public static IReadOnlyList<IElement> FindAllByLabelText(this IRenderedComponent<IComponent> renderedComponent, string labelText, Action<ByLabelTextOptions>? configureOptions = null)
	{
		var options = ByLabelTextOptions.Default;
		if (configureOptions is not null)
		{
			options = options with { };
			configureOptions.Invoke(options);
		}

		return FindAllByLabelTextInternal(renderedComponent, labelText, options);
	}

	internal static IElement? FindByLabelTextInternal(this IRenderedComponent<IComponent> renderedComponent, string labelText, ByLabelTextOptions options)
	{
		foreach (var strategy in LabelTextQueryStrategies)
		{
			var element = strategy.FindElement(renderedComponent, labelText, options);

			if (element is not null)
				return element;
		}

		return null;
	}

	internal static IReadOnlyList<IElement> FindAllByLabelTextInternal(this IRenderedComponent<IComponent> renderedComponent, string labelText, ByLabelTextOptions options)
	{
		var results = new List<IElement>();

		foreach (var strategy in LabelTextQueryStrategies)
		{
			results.AddRange(strategy.FindElements(renderedComponent, labelText, options));
		}

		var seen = new HashSet<IElement>();
		var distinctResults = new List<IElement>();

		foreach (var element in results)
		{
			var underlyingElement = element.Unwrap();
			if (seen.Add(underlyingElement))
			{
				distinctResults.Add(element);
			}
		}

		return distinctResults;
	}
}