using System.ComponentModel.DataAnnotations;
using Prefab.Data;

namespace Prefab.Domain.Common;

/// <summary>
/// Represents an audited entity that also tracks status transitions such as deactivate and delete.
/// </summary>
/// <typeparam name="T">The identifier type.</typeparam>
public interface IEntityWithAuditAndStatus<T> : IEntityWithAudit<T>, IStatus
{
    /// <summary>
    /// Gets or sets the identifier of the user that deactivated the entity.
    /// </summary>
    Guid? InactivatedBy { get; set; }

    /// <summary>
    /// Gets or sets when the entity was deactivated.
    /// </summary>
    DateTimeOffset? InactivatedOn { get; set; }

    /// <summary>
    /// Gets or sets the identifier of the user that soft-deleted the entity.
    /// </summary>
    Guid? DeletedBy { get; set; }

    /// <summary>
    /// Gets or sets when the entity was soft-deleted.
    /// </summary>
    DateTimeOffset? DeletedOn { get; set; }

    /// <summary>
    /// Gets or sets the concurrency token used for optimistic locking.
    /// </summary>
    byte[] RowVersion { get; set; }
}

/// <summary>
/// Base type for audited entities that support activation, deactivation, and soft-delete flows.
/// </summary>
/// <typeparam name="T">The identifier type.</typeparam>
public abstract class EntityWithAuditAndStatus<T> : EntityWithAudit<T>, IEntityWithAuditAndStatus<T>
{
    /// <inheritdoc />
    public AuditStatus AuditStatus => DeletedOn.HasValue
        ? AuditStatus.Deleted
        : InactivatedOn.HasValue
            ? AuditStatus.Inactive
            : AuditStatus.Active;

    /// <inheritdoc />
    public Guid? InactivatedBy { get; set; }

    /// <inheritdoc />
    public DateTimeOffset? InactivatedOn { get; set; }

    /// <inheritdoc />
    public Guid? DeletedBy { get; set; }

    /// <inheritdoc />
    public DateTimeOffset? DeletedOn { get; set; }

    /// <inheritdoc />
    [Timestamp]
    public byte[] RowVersion { get; set; } = [];

    /// <summary>
    /// Marks the entity as active by clearing any inactive markers.
    /// </summary>
    /// <param name="userId">Identifier of the user performing the change.</param>
    public virtual void Activate(Guid? userId = null)
    {
        if (InactivatedOn.HasValue)
        {
            InactivatedOn = null;
            InactivatedBy = null;
        }
    }

    /// <summary>
    /// Marks the entity as inactive if it is not already inactive.
    /// </summary>
    /// <param name="userId">Identifier of the user performing the change.</param>
    public virtual void Deactivate(Guid? userId = null)
    {
        if (!InactivatedOn.HasValue)
        {
            InactivatedOn = DateTimeOffset.UtcNow;
            InactivatedBy = userId;
        }
    }

    /// <summary>
    /// Soft deletes the entity when it has not already been deleted.
    /// </summary>
    /// <param name="userId">Identifier of the user performing the change.</param>
    public virtual void Delete(Guid? userId = null)
    {
        if (!DeletedOn.HasValue)
        {
            DeletedOn = DateTimeOffset.UtcNow;
            DeletedBy = userId;
        }
    }

    /// <summary>
    /// Restores a previously soft-deleted entity to an inactive state.
    /// </summary>
    /// <param name="userId">Identifier of the user performing the change.</param>
    public virtual void Restore(Guid? userId = null)
    {
        if (DeletedOn.HasValue)
        {
            DeletedOn = null;
            DeletedBy = null;
        }
    }
}