// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschraenkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using Microsoft.Extensions.Options;
using OpenIddict.Abstractions;
using Squidex.Config;
using Squidex.Domain.Apps.Core.Apps;
using Squidex.Domain.Apps.Entities;
using Squidex.Domain.Users;
using Squidex.Domain.Users.InMemory;
using Squidex.Hosting;
using Squidex.Infrastructure;
using Squidex.Shared.Identity;
using Squidex.Shared.Users;
using Squidex.Web;
using static OpenIddict.Abstractions.OpenIddictConstants;

namespace Squidex.Areas.IdentityServer.Config
{
    public class DynamicApplicationStore : InMemoryApplicationStore
    {
        private readonly IServiceProvider serviceProvider;

        public DynamicApplicationStore(IServiceProvider serviceProvider)
            : base(CreateStaticClients(serviceProvider))
        {
            this.serviceProvider = serviceProvider;
        }

        public override async ValueTask<ImmutableApplication?> FindByIdAsync(string identifier,
            CancellationToken cancellationToken)
        {
            var application = await base.FindByIdAsync(identifier, cancellationToken);

            if (application == null)
            {
                application = await GetDynamicAsync(identifier);
            }

            return application;
        }

        public override async ValueTask<ImmutableApplication?> FindByClientIdAsync(string identifier,
            CancellationToken cancellationToken)
        {
            var application = await base.FindByClientIdAsync(identifier, cancellationToken);

            if (application == null)
            {
                application = await GetDynamicAsync(identifier);
            }

            return application;
        }

        private async Task<ImmutableApplication?> GetDynamicAsync(string clientId)
        {
            var (appName, appClientId) = clientId.GetClientParts();

            var appProvider = serviceProvider.GetRequiredService<IAppProvider>();

            if (!string.IsNullOrWhiteSpace(appName) && !string.IsNullOrWhiteSpace(appClientId))
            {
                var app = await appProvider.GetAppAsync(appName, true);

                var appClient = app?.Clients.GetValueOrDefault(appClientId);

                if (appClient != null)
                {
                    return CreateClientFromApp(clientId, appClient);
                }
            }

            await using (var scope = serviceProvider.CreateAsyncScope())
            {
                var userService = scope.ServiceProvider.GetRequiredService<IUserService>();

                var user = await userService.FindByIdAsync(clientId);

                if (user == null)
                {
                    return null;
                }

                var secret = user.Claims.ClientSecret();

                if (!string.IsNullOrWhiteSpace(secret))
                {
                    return CreateClientFromUser(user, secret);
                }
            }

            return null;
        }

        private static ImmutableApplication CreateClientFromUser(IUser user, string secret)
        {
            return new ImmutableApplication(user.Id, new OpenIddictApplicationDescriptor
            {
                DisplayName = $"{user.Email} Client",
                ClientId = user.Id,
                ClientSecret = secret,
                Permissions =
                {
                    Permissions.Endpoints.Token,
                    Permissions.GrantTypes.ClientCredentials,
                    Permissions.ResponseTypes.Token,
                    Permissions.Scopes.Email,
                    Permissions.Scopes.Profile,
                    Permissions.Scopes.Roles,
                    Permissions.Prefixes.Scope + Constants.ScopeApi,
                    Permissions.Prefixes.Scope + Constants.ScopePermissions
                }
            }.CopyClaims(user));
        }

        private static ImmutableApplication CreateClientFromApp(string id, AppClient appClient)
        {
            return new ImmutableApplication(id, new OpenIddictApplicationDescriptor
            {
                DisplayName = id,
                ClientId = id,
                ClientSecret = appClient.Secret,
                Permissions =
                {
                    Permissions.Endpoints.Token,
                    Permissions.GrantTypes.ClientCredentials,
                    Permissions.ResponseTypes.Token,
                    Permissions.Scopes.Email,
                    Permissions.Scopes.Profile,
                    Permissions.Scopes.Roles,
                    Permissions.Prefixes.Scope + Constants.ScopeApi,
                    Permissions.Prefixes.Scope + Constants.ScopePermissions
                }
            });
        }

        private static IEnumerable<(string, OpenIddictApplicationDescriptor)> CreateStaticClients(IServiceProvider serviceProvider)
        {
            var identityOptions = serviceProvider.GetRequiredService<IOptions<MyIdentityOptions>>().Value;

            var urlGenerator = serviceProvider.GetRequiredService<IUrlGenerator>();

            var frontendId = Constants.ClientFrontendId;

            yield return (frontendId, new OpenIddictApplicationDescriptor
            {
                DisplayName = "Frontend Client",
                ClientId = frontendId,
                ClientSecret = null,
                RedirectUris =
                {
                    new Uri(urlGenerator.BuildUrl("login;")),
                    new Uri(urlGenerator.BuildUrl("client-callback-silent.html", false)),
                    new Uri(urlGenerator.BuildUrl("client-callback-popup.html", false))
                },
                PostLogoutRedirectUris =
                {
                    new Uri(urlGenerator.BuildUrl("logout", false))
                },
                Permissions =
                {
                    Permissions.Endpoints.Authorization,
                    Permissions.Endpoints.Logout,
                    Permissions.Endpoints.Token,
                    Permissions.GrantTypes.AuthorizationCode,
                    Permissions.GrantTypes.RefreshToken,
                    Permissions.ResponseTypes.Code,
                    Permissions.Scopes.Email,
                    Permissions.Scopes.Profile,
                    Permissions.Scopes.Roles,
                    Permissions.Prefixes.Scope + Constants.ScopeApi,
                    Permissions.Prefixes.Scope + Constants.ScopePermissions
                },
                Type = ClientTypes.Public
            });

            var internalClientId = Constants.ClientInternalId;

            yield return (internalClientId, new OpenIddictApplicationDescriptor
            {
                DisplayName = "Internal Client",
                ClientId = internalClientId,
                ClientSecret = Constants.ClientInternalSecret,
                RedirectUris =
                {
                    new Uri(urlGenerator.BuildUrl("/signin-internal", false))
                },
                Permissions =
                {
                    Permissions.Endpoints.Authorization,
                    Permissions.Endpoints.Logout,
                    Permissions.Endpoints.Token,
                    Permissions.GrantTypes.Implicit,
                    Permissions.ResponseTypes.IdToken,
                    Permissions.ResponseTypes.IdTokenToken,
                    Permissions.ResponseTypes.Token,
                    Permissions.Scopes.Email,
                    Permissions.Scopes.Profile,
                    Permissions.Scopes.Roles,
                    Permissions.Prefixes.Scope + Constants.ScopeApi,
                    Permissions.Prefixes.Scope + Constants.ScopePermissions
                },
                Type = ClientTypes.Public
            });

            if (!identityOptions.IsAdminClientConfigured())
            {
                yield break;
            }

            var adminClientId = identityOptions.AdminClientId;

            yield return (adminClientId, new OpenIddictApplicationDescriptor
            {
                DisplayName = "Admin Client",
                ClientId = adminClientId,
                ClientSecret = identityOptions.AdminClientSecret,
                Permissions =
                {
                    Permissions.Endpoints.Token,
                    Permissions.GrantTypes.ClientCredentials,
                    Permissions.ResponseTypes.Token,
                    Permissions.Scopes.Email,
                    Permissions.Scopes.Profile,
                    Permissions.Scopes.Roles,
                    Permissions.Prefixes.Scope + Constants.ScopeApi,
                    Permissions.Prefixes.Scope + Constants.ScopePermissions
                }
            }.SetAdmin());
        }
    }
}