using System;
using System.Threading;
using System.Threading.Tasks;

namespace Svrnty.CQRS.Sagas.Abstractions.Messaging;

/// <summary>
/// Abstraction for saga messaging transport.
/// </summary>
public interface ISagaMessageBus
{
    /// <summary>
    /// Publishes a saga command message to the message bus.
    /// </summary>
    /// <param name="message">The message to publish.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    Task PublishAsync(SagaMessage message, CancellationToken cancellationToken = default);

    /// <summary>
    /// Publishes a saga step response to the message bus.
    /// </summary>
    /// <param name="response">The response to publish.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    Task PublishResponseAsync(SagaStepResponse response, CancellationToken cancellationToken = default);

    /// <summary>
    /// Subscribes to saga messages for a specific command type.
    /// </summary>
    /// <typeparam name="TCommand">The command type to subscribe to.</typeparam>
    /// <param name="handler">Handler that processes the message and returns a response.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    Task SubscribeAsync<TCommand>(
        Func<SagaMessage, TCommand, CancellationToken, Task<SagaStepResponse>> handler,
        CancellationToken cancellationToken = default) where TCommand : class;

    /// <summary>
    /// Subscribes to saga step responses.
    /// </summary>
    /// <param name="handler">Handler that processes responses.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    Task SubscribeToResponsesAsync(
        Func<SagaStepResponse, CancellationToken, Task> handler,
        CancellationToken cancellationToken = default);
}