/*
 * Licensed under the Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)
 * See https://github.com/openiddict/openiddict-core for more information concerning
 * the license and the contributors participating to this project.
 */

using Microsoft.Extensions.DependencyInjection.Extensions;
using Microsoft.Extensions.Options;
using OpenIddict.Server;
using OpenIddict.Server.Owin;

namespace Microsoft.Extensions.DependencyInjection;

/// <summary>
/// Exposes extensions allowing to register the OpenIddict server services.
/// </summary>
public static class OpenIddictServerOwinExtensions
{
    /// <summary>
    /// Registers the OpenIddict server services for OWIN in the DI container.
    /// </summary>
    /// <param name="builder">The services builder used by OpenIddict to register new services.</param>
    /// <remarks>This extension can be safely called multiple times.</remarks>
    /// <returns>The <see cref="OpenIddictServerOwinBuilder"/> instance.</returns>
    public static OpenIddictServerOwinBuilder UseOwin(this OpenIddictServerBuilder builder)
    {
        ArgumentNullException.ThrowIfNull(builder);

        builder.Services.AddWebEncoders();

        // Note: unlike regular OWIN middleware, the OpenIddict server middleware is registered
        // as a scoped service in the DI container. This allows containers that support middleware
        // resolution (like Autofac) to use it without requiring additional configuration.
        builder.Services.TryAddScoped<OpenIddictServerOwinMiddleware>();

        // Register the built-in event handlers used by the OpenIddict OWIN server components.
        // Note: the order used here is not important, as the actual order is set in the options.
        builder.Services.TryAdd(OpenIddictServerOwinHandlers.DefaultHandlers.Select(descriptor => descriptor.ServiceDescriptor));

        // Register the built-in filters used by the default OpenIddict OWIN server event handlers.
        builder.Services.TryAddSingleton<RequireAuthorizationEndpointPassthroughEnabled>();
        builder.Services.TryAddSingleton<RequireEndSessionEndpointPassthroughEnabled>();
        builder.Services.TryAddSingleton<RequireErrorPassthroughEnabled>();
        builder.Services.TryAddSingleton<RequireTransportSecurityRequirementEnabled>();
        builder.Services.TryAddSingleton<RequireOwinRequest>();
        builder.Services.TryAddSingleton<RequireTokenEndpointPassthroughEnabled>();
        builder.Services.TryAddSingleton<RequireUserInfoEndpointPassthroughEnabled>();
        builder.Services.TryAddSingleton<RequireVerificationEndpointPassthroughEnabled>();

        // Register the option initializers used by the OpenIddict OWIN server integration services.
        // Note: TryAddEnumerable() is used here to ensure the initializers are only registered once.
        builder.Services.TryAddEnumerable(ServiceDescriptor.Singleton<
            IConfigureOptions<OpenIddictServerOptions>, OpenIddictServerOwinConfiguration>());

        builder.Services.TryAddEnumerable(ServiceDescriptor.Singleton<
            IPostConfigureOptions<OpenIddictServerOwinOptions>, OpenIddictServerOwinConfiguration>());

        builder.Services.TryAddEnumerable(ServiceDescriptor.Singleton<
            IPostConfigureOptions<OpenIddictServerOptions>, OpenIddictServerOwinConfiguration>());

        return new OpenIddictServerOwinBuilder(builder.Services);
    }

    /// <summary>
    /// Registers the OpenIddict server services for OWIN in the DI container.
    /// </summary>
    /// <param name="builder">The services builder used by OpenIddict to register new services.</param>
    /// <param name="configuration">The configuration delegate used to configure the server services.</param>
    /// <remarks>This extension can be safely called multiple times.</remarks>
    /// <returns>The <see cref="OpenIddictServerBuilder"/> instance.</returns>
    public static OpenIddictServerBuilder UseOwin(
        this OpenIddictServerBuilder builder, Action<OpenIddictServerOwinBuilder> configuration)
    {
        ArgumentNullException.ThrowIfNull(builder);
        ArgumentNullException.ThrowIfNull(configuration);

        configuration(builder.UseOwin());

        return builder;
    }
}