using MediatR;
using mws.backend.dotnet.application.Common;
using mws.backend.dotnet.domain.Audit;

namespace mws.backend.dotnet.application.Audit;

public class AuditLogBehavior<TRequest, TResponse>(
    IUnitOfWork uow,
    ICurrentUser currentUser,
    IAuditContext auditContext)
    : IPipelineBehavior<TRequest, TResponse> where TRequest : notnull
{
    public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken ct)
    {
        if (request is not IAuditableRequest auditable)
        {
            return await next();
        }

        auditContext.EntityId = null;
        auditContext.EntityName = null;

        var response = await next();

        uow.ActionLogs.Add(new ActionLog
        {
            Id = Guid.NewGuid(),
            ActorUserId = currentUser.UserId ?? Guid.Empty,
            ActorUsername = TruncateRequired(currentUser.Username ?? "unknown", 100),
            Action = auditable.Action,
            EntityType = auditable.EntityType,
            EntityId = auditable.EntityId ?? auditContext.EntityId ?? (response as IHasEntityId)?.EntityId,
            EntityName = Truncate(auditable.EntityName ?? auditContext.EntityName, 255),
            IpAddress = currentUser.IpAddress,
            UserAgent = currentUser.UserAgent,
            CreatedAt = DateTimeOffset.UtcNow,
        });
        await uow.SaveChangesAsync(ct);

        return response;
    }

    private static string TruncateRequired(string value, int max) =>
        value.Length <= max ? value : value[..max];

    private static string? Truncate(string? value, int max) =>
        value is null || value.Length <= max ? value : value[..max];
}