using System.Collections.Concurrent;
using Big.Application;
using Big.Domain;

namespace Big.Infrastructure;

/// <summary>
/// In-memory <see cref="IRegistrationStore"/> for the minimal slice (ADR-0009). The walking
/// skeleton's read path is the projection (S-06), not this store, so durable domain persistence is a
/// documented follow-up. Registered as a singleton so the submit endpoint and the worker share it.
/// </summary>
public sealed class InMemoryRegistrationStore : IRegistrationStore
{
    private readonly ConcurrentDictionary<RegistrationId, Registration> _byId = new();

    public Task SaveAsync(Registration registration, CancellationToken ct = default)
    {
        ArgumentNullException.ThrowIfNull(registration);
        _byId[registration.Id] = registration;
        return Task.CompletedTask;
    }

    public Task<Registration?> GetAsync(RegistrationId id, CancellationToken ct = default)
        => Task.FromResult(_byId.GetValueOrDefault(id));

    public Task<Registration?> FindOpenByBsnAsync(string bsn, CancellationToken ct = default)
        => Task.FromResult(_byId.Values.FirstOrDefault(r =>
            r.Bsn == bsn && r.Status is RegistrationStatus.Ingediend or RegistrationStatus.InBehandeling));

    public Task<IReadOnlyList<Registration>> FindDueForHerregistratieReminderAsync(
        DateTimeOffset asOf, CancellationToken ct = default)
        => Task.FromResult<IReadOnlyList<Registration>>(
            _byId.Values.Where(r => r.HerregistratieReminderDue(asOf)).ToList());
}