using Microsoft.Extensions.DependencyInjection;
using System.Threading.Channels;

namespace Prefab.Data.Seeder;

public static class Extensions
{
    /// <summary>
    /// Registers a seeder and its options so it can participate in environment-aware execution.
    /// </summary>
    /// <typeparam name="TSeeder">Seeder implementation.</typeparam>
    /// <param name="services">The host service collection.</param>
    /// <param name="runMode">Determines when the seeder is allowed to run.</param>
    /// <returns>The provided service collection.</returns>
    public static IServiceCollection AddSeeder<TSeeder>(this IServiceCollection services, RunMode runMode = RunMode.RunOnFirstLoadOnly) where TSeeder : class, ISeeder
    {
        services.AddScoped<ISeeder, TSeeder>();
        services.AddScoped<TSeeder>();
        services.Configure<SeederOptions<TSeeder>>(opts => opts.RunMode = runMode);

        return services;
    }

    /// <summary>
    /// Gets the channel used to queue seeder operations for background execution.
    /// </summary>
    public static Channel<Func<IServiceProvider, CancellationToken, Task>> Channel { get; }
        = System.Threading.Channels.Channel.CreateUnbounded<Func<IServiceProvider, CancellationToken, Task>>();
}