dotnet-cqrs/Svrnty.CQRS.Events.ConsumerGroups/ServiceCollectionExtensions.cs

using System;
using Svrnty.CQRS.Events.ConsumerGroups.PostgreSQL;
using Svrnty.CQRS.Events.ConsumerGroups.Monitoring;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Svrnty.CQRS.Events.ConsumerGroups.Abstractions;

namespace Svrnty.CQRS.Events.ConsumerGroups;

/// <summary>
/// Extension methods for registering consumer group services.
/// </summary>
public static class ServiceCollectionExtensions
{
    /// <summary>
    /// Adds PostgreSQL-based consumer group support with health monitoring.
    /// Registers IConsumerOffsetStore, IConsumerGroupReader, and the health monitor background service.
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="configureStorage">Action to configure PostgreSQL storage options.</param>
    /// <param name="configureHealthMonitor">Optional action to configure health monitor options.</param>
    /// <returns>The service collection for chaining.</returns>
    public static IServiceCollection AddPostgresConsumerGroups(
        this IServiceCollection services,
        Action<PostgresConsumerGroupOptions> configureStorage,
        Action<ConsumerHealthMonitorOptions>? configureHealthMonitor = null)
    {
        if (services == null)
            throw new ArgumentNullException(nameof(services));
        if (configureStorage == null)
            throw new ArgumentNullException(nameof(configureStorage));

        // Configure storage options
        services.Configure(configureStorage);

        // Configure health monitor options (if provided)
        if (configureHealthMonitor != null)
        {
            services.Configure(configureHealthMonitor);
        }

        // Register core services
        services.TryAddSingleton<IConsumerOffsetStore, PostgresConsumerOffsetStore>();
        services.TryAddSingleton<IConsumerGroupReader, PostgresConsumerGroupReader>();

        // Register health monitor as hosted service
        services.AddHostedService<ConsumerHealthMonitor>();

        return services;
    }

    /// <summary>
    /// Adds PostgreSQL-based consumer group support with health monitoring.
    /// Registers IConsumerOffsetStore, IConsumerGroupReader, and the health monitor background service.
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="storageConfiguration">Configuration section for PostgreSQL storage options.</param>
    /// <param name="healthMonitorConfiguration">Optional configuration section for health monitor options.</param>
    /// <returns>The service collection for chaining.</returns>
    public static IServiceCollection AddPostgresConsumerGroups(
        this IServiceCollection services,
        IConfigurationSection storageConfiguration,
        IConfigurationSection? healthMonitorConfiguration = null)
    {
        if (services == null)
            throw new ArgumentNullException(nameof(services));
        if (storageConfiguration == null)
            throw new ArgumentNullException(nameof(storageConfiguration));

        // Configure storage options from configuration
        services.Configure<PostgresConsumerGroupOptions>(options => storageConfiguration.Bind(options));

        // Configure health monitor options from configuration (if provided)
        if (healthMonitorConfiguration != null)
        {
            services.Configure<ConsumerHealthMonitorOptions>(options => healthMonitorConfiguration.Bind(options));
        }

        // Register core services
        services.TryAddSingleton<IConsumerOffsetStore, PostgresConsumerOffsetStore>();
        services.TryAddSingleton<IConsumerGroupReader, PostgresConsumerGroupReader>();

        // Register health monitor as hosted service
        services.AddHostedService<ConsumerHealthMonitor>();

        return services;
    }

    /// <summary>
    /// Adds consumer offset store implementation.
    /// Use this if you only need offset tracking without the full consumer group reader.
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="configureStorage">Action to configure PostgreSQL storage options.</param>
    /// <returns>The service collection for chaining.</returns>
    public static IServiceCollection AddPostgresConsumerOffsetStore(
        this IServiceCollection services,
        Action<PostgresConsumerGroupOptions> configureStorage)
    {
        if (services == null)
            throw new ArgumentNullException(nameof(services));
        if (configureStorage == null)
            throw new ArgumentNullException(nameof(configureStorage));

        services.Configure(configureStorage);
        services.TryAddSingleton<IConsumerOffsetStore, PostgresConsumerOffsetStore>();

        return services;
    }

    /// <summary>
    /// Adds consumer offset store implementation.
    /// Use this if you only need offset tracking without the full consumer group reader.
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="storageConfiguration">Configuration section for PostgreSQL storage options.</param>
    /// <returns>The service collection for chaining.</returns>
    public static IServiceCollection AddPostgresConsumerOffsetStore(
        this IServiceCollection services,
        IConfigurationSection storageConfiguration)
    {
        if (services == null)
            throw new ArgumentNullException(nameof(services));
        if (storageConfiguration == null)
            throw new ArgumentNullException(nameof(storageConfiguration));

        services.Configure<PostgresConsumerGroupOptions>(options => storageConfiguration.Bind(options));
        services.TryAddSingleton<IConsumerOffsetStore, PostgresConsumerOffsetStore>();

        return services;
    }

    /// <summary>
    /// Adds the consumer health monitor background service.
    /// Requires IConsumerOffsetStore to be registered.
    /// </summary>
    /// <param name="services">The service collection.</param>
    /// <param name="configure">Optional action to configure health monitor options.</param>
    /// <returns>The service collection for chaining.</returns>
    public static IServiceCollection AddConsumerHealthMonitor(
        this IServiceCollection services,
        Action<ConsumerHealthMonitorOptions>? configure = null)
    {
        if (services == null)
            throw new ArgumentNullException(nameof(services));

        if (configure != null)
        {
            services.Configure(configure);
        }

        services.AddHostedService<ConsumerHealthMonitor>();

        return services;
    }
}