using System;
using Svrnty.CQRS.Events.Abstractions.Subscriptions;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Svrnty.CQRS.Events.Abstractions.Models;

namespace Svrnty.CQRS.Events.Abstractions.Subscriptions;

/// <summary>
/// Storage abstraction for persisting and retrieving event subscriptions.
/// Implementations can use any storage mechanism (SQL, NoSQL, in-memory, etc.).
/// </summary>
public interface ISubscriptionStore
{
    /// <summary>
    /// Create a new subscription.
    /// </summary>
    /// <param name="subscription">The subscription to create.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    Task CreateAsync(EventSubscription subscription, CancellationToken cancellationToken = default);

    /// <summary>
    /// Get a subscription by its ID.
    /// </summary>
    /// <param name="subscriptionId">The subscription ID.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>The subscription, or null if not found.</returns>
    Task<EventSubscription?> GetByIdAsync(string subscriptionId, CancellationToken cancellationToken = default);

    /// <summary>
    /// Get all active subscriptions for a specific subscriber.
    /// </summary>
    /// <param name="subscriberId">The subscriber ID.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>List of subscriptions.</returns>
    Task<List<EventSubscription>> GetBySubscriberIdAsync(string subscriberId, CancellationToken cancellationToken = default);

    /// <summary>
    /// Find all active subscriptions for a specific correlation ID.
    /// Used to determine which subscribers should receive an event.
    /// </summary>
    /// <param name="correlationId">The correlation ID.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>List of active subscriptions.</returns>
    Task<List<EventSubscription>> FindByCorrelationIdAsync(string correlationId, CancellationToken cancellationToken = default);

    /// <summary>
    /// Update an existing subscription (e.g., to update LastDeliveredSequence or Status).
    /// </summary>
    /// <param name="subscription">The subscription to update.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    Task UpdateAsync(EventSubscription subscription, CancellationToken cancellationToken = default);

    /// <summary>
    /// Delete a subscription.
    /// </summary>
    /// <param name="subscriptionId">The subscription ID to delete.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    Task DeleteAsync(string subscriptionId, CancellationToken cancellationToken = default);

    /// <summary>
    /// Delete expired or completed subscriptions older than the specified date.
    /// </summary>
    /// <param name="olderThan">Delete subscriptions completed/expired before this date.</param>
    /// <param name="cancellationToken">Cancellation token.</param>
    /// <returns>Number of subscriptions deleted.</returns>
    Task<int> DeleteOldSubscriptionsAsync(DateTimeOffset olderThan, CancellationToken cancellationToken = default);
}