ClockKernelExtension.cs

// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.Threading.Tasks;
using Microsoft.DotNet.Interactive;
using Microsoft.DotNet.Interactive.Directives;
using Microsoft.DotNet.Interactive.Formatting;
using static Microsoft.DotNet.Interactive.Formatting.PocketViewTags;

namespace ClockExtension;

public static class ClockKernelExtension
{
    public static void Load(Kernel kernel)
    {
        // Register formatters that will change the default output when formatting DateTime and DateTimeOffset instances as text/html.
        Formatter.Register<DateTime>((date, writer) => writer.Write(date.DrawSvgClock()), "text/html");

        Formatter.Register<DateTimeOffset>((date, writer) => writer.Write(date.DrawSvgClock()), "text/html");

        // Next, define a magic command that will render a clock.
        var hourParameter = new KernelDirectiveParameter("--hour", "The position of the hour hand");
        var minuteParameter = new KernelDirectiveParameter("--minute", "The position of the minute hand");
        var secondParameter = new KernelDirectiveParameter("--second", "The position of the second hand");

        var clockDirective = new KernelActionDirective("#!clock")
        {
            Description = "Displays a clock showing the current or specified time.",
            Parameters =
            [
                hourParameter,
                minuteParameter,
                secondParameter
            ]
        };

        kernel.AddDirective<DisplayClock>(clockDirective, (displayClock, context) =>
        {
            context.Display(SvgClock.DrawSvgClock(displayClock.Hour, displayClock.Minute, displayClock.Second));
            return Task.CompletedTask;
        });

        // Finally, display some information to the user so they can see how to use the extension.
        PocketView view = div(
            code(nameof(ClockExtension)),
            " is loaded. It adds visualizations for ",
            code(typeof(DateTime)),
            " and ",
            code(typeof(DateTimeOffset)),
            ". Try it by running: ",
            code("DateTime.Now")
        );

        KernelInvocationContext.Current?.Display(view);
    }
}