elsa-core/src/modules/Elsa.MassTransit/Extensions/MassTransitFeatureExtensions.cs

using Elsa.Features.Services;
using Elsa.MassTransit.Features;
using Elsa.MassTransit.Implementations;
using Elsa.MassTransit.Models;
using MassTransit;

// ReSharper disable once CheckNamespace
namespace Elsa.Extensions;

/// <summary>
/// Provides extensions to <see cref="IModule"/> that enables and configures MassTransit.
/// </summary>
public static class MassTransitFeatureExtensions
{
    private static readonly object ServiceBusConsumerTypesKey = new();
    private static readonly object MessageTypesKey = new();

    /// <summary>
    /// Registers the specified type for MassTransit service bus consumer discovery.
    /// </summary>
    public static MassTransitFeature AddConsumer<T>(this MassTransitFeature feature, string? name, bool isTemporary) where T : IConsumer => feature.AddConsumer(typeof(T), name, isTemporary);

    /// <summary>
    /// Registers the specified type for MassTransit service bus consumer discovery.
    /// </summary>
    /// <typeparam name="T">The consumer type.</typeparam>
    /// <typeparam name="TDefinition">The consumer definition type.</typeparam>
    public static MassTransitFeature AddConsumer<T, TDefinition>(this MassTransitFeature feature, string? name, bool isTemporary) 
        where T : IConsumer 
        where TDefinition : IConsumerDefinition
    {
        return feature.AddConsumer(typeof(T), name, isTemporary, typeof(TDefinition));
    }

    /// <summary>
    /// Registers the specified type for MassTransit service bus consumer discovery.
    /// </summary>
    public static MassTransitFeature AddConsumer(this MassTransitFeature feature, Type type, string? name, bool isTemporary,
        Type? consumerDefinitionType = default)
    {
        var types = feature.Module.Properties.GetOrAdd(ServiceBusConsumerTypesKey, () => new HashSet<ConsumerTypeDefinition>());
        types.Add(new ConsumerTypeDefinition(type, consumerDefinitionType, name, isTemporary));
        return feature;
    }

    /// <summary>
    /// Registers a message type which is to be used by the <see cref="MassTransitActivityTypeProvider"/> to dynamically provide activities to send and receive these messages.
    /// </summary>
    public static MassTransitFeature AddMessageType<T>(this MassTransitFeature feature) where T : class => feature.AddMessageType(typeof(T));

    /// <summary>
    /// Registers a message type which is to be used by the <see cref="MassTransitActivityTypeProvider"/> to dynamically provide activities to send and receive these messages.
    /// </summary>
    public static MassTransitFeature AddMessageType(this MassTransitFeature feature, Type type)
    {
        var types = feature.Module.Properties.GetOrAdd(MessageTypesKey, () => new HashSet<Type>());
        types.Add(type);
        return feature;
    }

    /// <summary>
    /// Returns all collected consumer types.
    /// </summary>
    public static IEnumerable<ConsumerTypeDefinition> GetConsumers(this MassTransitFeature feature) => feature.Module.Properties.GetOrAdd(ServiceBusConsumerTypesKey, () => new HashSet<ConsumerTypeDefinition>());

    /// <summary>
    /// Returns all collected message types.
    /// </summary>
    internal static IEnumerable<Type> GetMessages(this MassTransitFeature feature) => feature.Module.Properties.GetOrAdd(MessageTypesKey, () => new HashSet<Type>());
}