using Microsoft.AspNetCore.Components;

namespace Elternbeirat.Web.Shared;

/// <summary>
///     Renders a decorative line icon from <see cref="IconSet"/> as inline SVG.
/// </summary>
/// <remarks>
///     Inline SVG, not an <c>&lt;img&gt;</c> or icon font: no extra request, nothing
///     from a third-party host, and the icon follows the text colour (including dark
///     mode) through <c>currentColor</c>. The icon is hidden from assistive technology,
///     so it must never be the only carrier of meaning.
/// </remarks>
/// <example>
///     <code>
///         &lt;Icon Name="map-pin" /&gt; Aula
///         &lt;Icon Name="calendar" Size="16" /&gt;
///     </code>
/// </example>
/// <seealso cref="IconSet"/>
public partial class Icon
{
    /// <summary>
    ///     The inner SVG markup of the current icon, or <see langword="null"/> when the
    ///     name is unknown and nothing should render.
    /// </summary>
    private MarkupString? _markup;

    /// <summary>
    ///     The icon name, e.g. <c>calendar</c>; see <see cref="IconSet"/> for the set.
    /// </summary>
    [Parameter]
    [EditorRequired]
    public string Name { get; set; } = "";

    /// <summary>
    ///     Width and height in CSS pixels. Defaults to <c>20</c>, which sits well next
    ///     to body text.
    /// </summary>
    [Parameter]
    public int Size { get; set; } = 20;

    /// <inheritdoc/>
    protected override void OnParametersSet() =>
        _markup = IconSet.Find(Name) is { } markup ? new MarkupString(markup) : null;
}