namespace SVSim.Database.Repositories.Card;

/// <summary>
/// Mutating operations on a viewer's card inventory (destruct, create, protect…).
/// Read-only catalog queries live on <see cref="ICardRepository"/>.
/// </summary>
public interface ICardInventoryRepository
{
    /// <summary>
    /// Validate-then-mutate destruct of owned cards. Atomic: all validation runs before any
    /// mutation, and the mutation phase is wrapped in an explicit DB transaction so a mid-flight
    /// EF failure rolls back currency + inventory + deck-strip together.
    /// </summary>
    /// <param name="viewerId">Authenticated viewer.</param>
    /// <param name="destructCounts">cardId → num_to_destruct. Empty dict is rejected by the caller.</param>
    /// <returns>
    ///   <see cref="DestructResult"/> with post-state totals on success, or a
    ///   <see cref="DestructError"/> when validation fails. On error nothing is written.
    /// </returns>
    Task<DestructOutcome> DestructCards(long viewerId, IReadOnlyDictionary<long, int> destructCounts);
}

/// <summary>
/// Either a success payload or an error code. Discriminated by which field is set.
/// </summary>
public sealed record DestructOutcome(DestructResult? Result, DestructError? Error)
{
    public bool IsSuccess => Result is not null;

    public static DestructOutcome Ok(DestructResult r) => new(r, null);
    public static DestructOutcome Fail(DestructError e) => new(null, e);
}

public sealed record DestructResult(
    ulong NewRedEtherTotal,
    IReadOnlyDictionary<long, int> NewOwnedCounts);   // cardId → post-destruct Count

public enum DestructError
{
    UnknownCard,
    NotDestructible,
    CardProtected,
    InsufficientCards,
}