using EventSubscriber.Application;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;

namespace Projection.ReadModel;

public static class ServiceCollectionExtensions
{
    /// <summary>Register the projection <see cref="ProjectionDbContext"/> against Postgres.</summary>
    public static IServiceCollection AddProjectionReadModel(this IServiceCollection services, string connectionString)
        => services.AddDbContext<ProjectionDbContext>(o => o.UseNpgsql(connectionString));

    /// <summary>Register the write-side ports (projector store + notification log) used by the Event Subscriber.</summary>
    public static IServiceCollection AddProjectionWriteSide(this IServiceCollection services)
    {
        services.AddScoped<IProjectionStore, EfProjectionStore>();
        services.AddScoped<INotificationLog, EfNotificationLog>();
        services.AddScoped<NotificationProjector>();
        return services;
    }

    /// <summary>Apply any pending EF migrations. Called once on service start so a fresh stack
    /// reaches a usable schema without a manual migration step (DoD: compose up reaches green).</summary>
    public static async Task MigrateProjectionAsync(this IServiceProvider services, CancellationToken ct = default)
    {
        await using var scope = services.CreateAsyncScope();
        var db = scope.ServiceProvider.GetRequiredService<ProjectionDbContext>();
        await db.Database.MigrateAsync(ct);
    }
}