// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using Microsoft.AspNet.Identity;
using Microsoft.Extensions.DependencyInjection.Extensions;

namespace Microsoft.Extensions.DependencyInjection
{
    /// <summary>
    /// Contains extension methods to <see cref="IServiceCollection"/> for configuring identity services.
    /// </summary>
    public static class IdentityServiceCollectionExtensions
    {
        /// <summary>
        /// Adds the default identity system configuration for the specified User and Role types.
        /// </summary>
        /// <typeparam name="TUser">The type representing a User in the system.</typeparam>
        /// <typeparam name="TRole">The type representing a Role in the system.</typeparam>
        /// <param name="services">The services available in the application.</param>
        /// <returns>An <see cref="IdentityBuilder"/> for creating and configuring the identity system.</returns>
        public static IdentityBuilder AddIdentity<TUser, TRole>(
            this IServiceCollection services)
            where TUser : class
            where TRole : class
        {
            return services.AddIdentity<TUser, TRole>(setupAction: null);
        }

        /// <summary>
        /// Adds and configures the identity system for the specified User and Role types.
        /// </summary>
        /// <typeparam name="TUser">The type representing a User in the system.</typeparam>
        /// <typeparam name="TRole">The type representing a Role in the system.</typeparam>
        /// <param name="services">The services available in the application.</param>
        /// <param name="setupAction">An action to configure the <see cref="IdentityOptions"/>.</param>
        /// <returns>An <see cref="IdentityBuilder"/> for creating and configuring the identity system.</returns>
        public static IdentityBuilder AddIdentity<TUser, TRole>(
            this IServiceCollection services, 
            Action<IdentityOptions> setupAction)
            where TUser : class
            where TRole : class
        {
            // Services used by identity
            services.AddOptions();
            services.AddAuthentication(options =>
            {
                // This is the Default value for ExternalCookieAuthenticationScheme
                options.SignInScheme = new IdentityCookieOptions().ExternalCookieAuthenticationScheme;
            });

            // Identity services
            services.TryAddSingleton<IdentityMarkerService>();
            services.TryAddScoped<IUserValidator<TUser>, UserValidator<TUser>>();
            services.TryAddScoped<IPasswordValidator<TUser>, PasswordValidator<TUser>>();
            services.TryAddScoped<IPasswordHasher<TUser>, PasswordHasher<TUser>>();
            services.TryAddScoped<ILookupNormalizer, UpperInvariantLookupNormalizer>();
            services.TryAddScoped<IRoleValidator<TRole>, RoleValidator<TRole>>();
            // No interface for the error describer so we can add errors without rev'ing the interface
            services.TryAddScoped<IdentityErrorDescriber>();
            services.TryAddScoped<ISecurityStampValidator, SecurityStampValidator<TUser>>();
            services.TryAddScoped<IUserClaimsPrincipalFactory<TUser>, UserClaimsPrincipalFactory<TUser, TRole>>();
            services.TryAddScoped<UserManager<TUser>, UserManager<TUser>>();
            services.TryAddScoped<SignInManager<TUser>, SignInManager<TUser>>();
            services.TryAddScoped<RoleManager<TRole>, RoleManager<TRole>>();

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

            return new IdentityBuilder(typeof(TUser), typeof(TRole), services);
        }
    }
}