using FictionArchive.Service.Shared.Models.Interfaces;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using NodaTime;

namespace FictionArchive.Service.Shared.Services.Database;

public class AuditInterceptor : SaveChangesInterceptor
{
    public override InterceptionResult<int> SavingChanges(
        DbContextEventData eventData,
        InterceptionResult<int> result)
    {
        var context = eventData.Context;
        SetAuditFields(context);


        return base.SavingChanges(eventData, result);
    }

    public override ValueTask<InterceptionResult<int>> SavingChangesAsync(DbContextEventData eventData, InterceptionResult<int> result,
        CancellationToken cancellationToken = new CancellationToken())
    {
        var context = eventData.Context;
        SetAuditFields(context);
        return base.SavingChangesAsync(eventData, result, cancellationToken);
    }

    private void SetAuditFields(DbContext? context)
    {
        if (context == null)
            return;

        var entries = context.ChangeTracker.Entries<IAuditable>();

        var now = Instant.FromDateTimeUtc(DateTime.UtcNow);

        foreach (var e in entries)
        {
            if (e.State == EntityState.Added)
            {
                e.Entity.CreatedTime = now;
                e.Entity.LastUpdatedTime = now;
            }
            else if (e.State == EntityState.Modified)
            {
                e.Entity.LastUpdatedTime = now;
            }
        }
    }
}