using ItWorx.KnowledgeHub.Application.Audit;

namespace ItWorx.KnowledgeHub.Application.Operations.UseCases;

public sealed record CreateBackupCommand(Guid ActorId, string? CorrelationId);

/// <summary>Administrator-triggered full backup (docs/18-backup-restore.md). Records
/// an audit event on both success and failure — a failed backup is itself an
/// operationally significant event (docs/19-observability.md "repeated backup
/// failure" alert).</summary>
public sealed class CreateBackupUseCase(IBackupService backups, IAuditEventRecorder auditEvents, TimeProvider timeProvider, PlatformMetrics? metrics = null)
{
    public async Task<BackupSummary> ExecuteAsync(CreateBackupCommand command, CancellationToken cancellationToken)
    {
        using var measurement = metrics?.Start("backup");
        var now = timeProvider.GetUtcNow();
        try
        {
            var summary = await backups.CreateBackupAsync(cancellationToken);

            await auditEvents.RecordAsync(
                new AuditEventRecord(
                    AuditActorKind.User,
                    command.ActorId,
                    Source: "web",
                    Action: "backup.created",
                    TargetType: "backup",
                    TargetId: summary.BackupId,
                    Summary: $"Back-up '{summary.BackupId}' aangemaakt ({summary.TableCount} tabellen, {summary.AttachmentCount} bijlagen).",
                    command.CorrelationId,
                    now),
                cancellationToken);

            measurement?.Complete(summary.AttachmentCount);
            return summary;
        }
        catch (Exception exception) when (exception is not OperationCanceledException)
        {
            await auditEvents.RecordAsync(
                new AuditEventRecord(
                    AuditActorKind.User,
                    command.ActorId,
                    Source: "web",
                    Action: "backup.failed",
                    TargetType: null,
                    TargetId: null,
                    // Exception messages from a controlled backup pipeline never carry
                    // secrets/connection strings (docs/19-observability.md "Never log
                    // ... connection strings"); the message itself is safe operator
                    // diagnostic text, not raw exception detail from user input.
                    Summary: $"Back-up mislukt: {exception.GetType().Name}.",
                    command.CorrelationId,
                    now),
                cancellationToken);

            throw;
        }
    }
}