VolcanicAgenticCore/extensions/Volcanic.AgenticCore.Extensions.GoogleCalendar/CalendarCommands.cs

using Volcanic.AgenticCore.Abstractions.Extensions;
using Volcanic.AgenticCore.Abstractions.Messages;
using Volcanic.AgenticCore.Abstractions.Ui;

namespace Volcanic.AgenticCore.Extensions.GoogleCalendar;

/// <summary>Replies through the UI, or as a custom message without a turn when there is none.</summary>
internal static class CommandReply
{
    public static void Send(IExtensionApi api, IExtensionContext ctx, string customType, string text, NotifyKind kind = NotifyKind.Info)
    {
        if (ctx.HasUi) ctx.Ui.Notify(text, kind);
        else api.SendMessage(CustomMessage.FromText(customType, text), MessageDelivery.Steer, triggerTurn: false);
    }
}

/// <summary><c>/calendar_connect</c>: runs this chat's device flow to the end (the command already runs off the update loop).</summary>
internal static class ConnectCommand
{
    public const string Name = "calendar_connect";
    public const string Description = "Connect this chat's Google Calendar (link + code)";

    public static CommandDefinition Create(IExtensionApi api, GoogleCalendarExtension extension) => new(Description, async (_, ctx, ct) =>
    {
        if (!ctx.HasUi)
        {
            CommandReply.Send(api, ctx, Name, $"/{Name} needs an interactive UI (a chat front end such as the Telegram bot).");
            return;
        }
        var connection = extension.ConnectionFor(ctx);
        var flow = await ConnectFlow.StartOrResendAsync(connection, ctx.Ui, ct).ConfigureAwait(false);
        if (flow is not null) await flow.RunAsync(ctx.Ui, ctx.Logger).ConfigureAwait(false);
    });
}

/// <summary><c>/calendar_status</c>.</summary>
internal static class StatusCommand
{
    public const string Name = "calendar_status";
    public const string Description = "Show this chat's Google Calendar connection";

    public static CommandDefinition Create(IExtensionApi api, GoogleCalendarExtension extension) => new(Description, (_, ctx, _) =>
    {
        var connection = extension.ConnectionFor(ctx);
        CommandReply.Send(api, ctx, Name, Describe(connection));
        return Task.CompletedTask;
    });

    internal static string Describe(GoogleCalendarConnection connection)
    {
        if (connection.Pending is { } flow)
        {
            var d = flow.Device;
            return $"Waiting for approval: open {d.VerificationUrl} and enter {d.UserCode} ({ConnectFlow.MinutesLeft(d, connection.Settings.Time)} min left).";
        }
        if (connection.Store.Read() is not { } token) return "Not connected. Run /calendar_connect.";
        var since = token.ConnectedAt?.ToString("yyyy-MM-dd", System.Globalization.CultureInfo.InvariantCulture) ?? "an unknown date";
        return $"Connected as {token.Account ?? "an unknown account"} since {since}, time zone {token.TimeZone ?? "unknown"}.";
    }
}

/// <summary><c>/calendar_disconnect</c>: cancel a pending flow, revoke (best effort), delete the file, drop the cache.</summary>
internal static class DisconnectCommand
{
    public const string Name = "calendar_disconnect";
    public const string Description = "Disconnect this chat's Google Calendar";

    public static CommandDefinition Create(IExtensionApi api, GoogleCalendarExtension extension) => new(Description, async (_, ctx, ct) =>
    {
        var connection = extension.ConnectionFor(ctx);
        string? revokeError;
        // The gate a completing connect flow writes its token under: after CancelPending it can no longer write.
        await connection.FlowGate.WaitAsync(ct).ConfigureAwait(false);
        try
        {
            connection.CancelPending();
            var token = connection.Store.Read();
            revokeError = token is null ? null : await connection.OAuth.RevokeAsync(token.RefreshToken, ct).ConfigureAwait(false);
            connection.Store.Delete();
            connection.Invalidate();
        }
        finally
        {
            connection.FlowGate.Release();
        }
        var text = "Calendar disconnected.";
        if (revokeError is not null)
            text += $" Revoking at Google failed: {revokeError}; remove the app at {GoogleCalendarMessages.PermissionsUrl}.";
        CommandReply.Send(api, ctx, Name, text);
    });
}