sec: return the token instead of performing actions with the user

.editorconfig

@@ -0,0 +1,278 @@
+# Удалите строку ниже, если вы хотите наследовать параметры .editorconfig из каталогов, расположенных выше в иерархии
+root = true
+
+# Файлы C#
+[*.cs]
+
+#### Основные параметры EditorConfig ####
+
+# Отступы и интервалы
+indent_size = 4
+indent_style = space
+tab_width = 4
+
+# Предпочтения для новых строк
+end_of_line = crlf
+insert_final_newline = false
+
+#### Действия кода .NET ####
+
+# Члены типа
+dotnet_hide_advanced_members = false
+dotnet_member_insertion_location = with_other_members_of_the_same_kind
+dotnet_property_generation_behavior = prefer_throwing_properties
+
+# Поиск символов
+dotnet_search_reference_assemblies = true
+
+#### Рекомендации по написанию кода .NET ####
+
+# Упорядочение Using
+dotnet_separate_import_directive_groups = false
+dotnet_sort_system_directives_first = false
+file_header_template = unset
+
+# Предпочтения для this. и Me.
+dotnet_style_qualification_for_event = false
+dotnet_style_qualification_for_field = false
+dotnet_style_qualification_for_method = false
+dotnet_style_qualification_for_property = false
+
+# Параметры использования ключевых слов языка и типов BCL
+dotnet_style_predefined_type_for_locals_parameters_members = true
+dotnet_style_predefined_type_for_member_access = true
+
+# Предпочтения для скобок
+dotnet_style_parentheses_in_arithmetic_binary_operators = always_for_clarity
+dotnet_style_parentheses_in_other_binary_operators = always_for_clarity
+dotnet_style_parentheses_in_other_operators = never_if_unnecessary
+dotnet_style_parentheses_in_relational_binary_operators = always_for_clarity
+
+# Предпочтения модификатора
+dotnet_style_require_accessibility_modifiers = for_non_interface_members
+
+# Выражения уровень предпочтения
+dotnet_prefer_system_hash_code = true
+dotnet_style_coalesce_expression = true
+dotnet_style_collection_initializer = true
+dotnet_style_explicit_tuple_names = true
+dotnet_style_namespace_match_folder = true
+dotnet_style_null_propagation = true
+dotnet_style_object_initializer = true
+dotnet_style_operator_placement_when_wrapping = beginning_of_line
+dotnet_style_prefer_auto_properties = true
+dotnet_style_prefer_collection_expression = when_types_loosely_match
+dotnet_style_prefer_compound_assignment = true
+dotnet_style_prefer_conditional_expression_over_assignment = true
+dotnet_style_prefer_conditional_expression_over_return = true
+dotnet_style_prefer_foreach_explicit_cast_in_source = when_strongly_typed
+dotnet_style_prefer_inferred_anonymous_type_member_names = true
+dotnet_style_prefer_inferred_tuple_names = true
+dotnet_style_prefer_is_null_check_over_reference_equality_method = true
+dotnet_style_prefer_simplified_boolean_expressions = true
+dotnet_style_prefer_simplified_interpolation = true
+
+# Предпочтения для полей
+dotnet_style_readonly_field = true
+
+# Настройки параметров
+dotnet_code_quality_unused_parameters = non_public
+
+# Параметры подавления
+dotnet_remove_unnecessary_suppression_exclusions = none
+
+# Предпочтения для новых строк
+dotnet_style_allow_multiple_blank_lines_experimental = true
+dotnet_style_allow_statement_immediately_after_block_experimental = false
+
+#### Рекомендации по написанию кода C# ####
+
+# Предпочтения var
+csharp_style_var_elsewhere = true:suggestion
+csharp_style_var_for_built_in_types = true:silent
+csharp_style_var_when_type_is_apparent = true:silent
+
+# Члены, заданные выражениями
+csharp_style_expression_bodied_accessors = true:silent
+csharp_style_expression_bodied_constructors = true:silent
+csharp_style_expression_bodied_indexers = true:silent
+csharp_style_expression_bodied_lambdas = true:silent
+csharp_style_expression_bodied_local_functions = true:silent
+csharp_style_expression_bodied_methods = true:silent
+csharp_style_expression_bodied_operators = true:silent
+csharp_style_expression_bodied_properties = true:silent
+
+# Настройки соответствия шаблонов
+csharp_style_pattern_matching_over_as_with_null_check = true:suggestion
+csharp_style_pattern_matching_over_is_with_cast_check = true:suggestion
+csharp_style_prefer_extended_property_pattern = true:suggestion
+csharp_style_prefer_not_pattern = true:suggestion
+csharp_style_prefer_pattern_matching = true:silent
+csharp_style_prefer_switch_expression = true:suggestion
+
+# Настройки проверки на null
+csharp_style_conditional_delegate_call = true:suggestion
+
+# Предпочтения модификатора
+csharp_prefer_static_anonymous_function = true:suggestion
+csharp_prefer_static_local_function = true:suggestion
+csharp_preferred_modifier_order = public,private,protected,internal,file,static,extern,new,virtual,abstract,sealed,override,readonly,unsafe,required,volatile,async
+csharp_style_prefer_readonly_struct = true:suggestion
+csharp_style_prefer_readonly_struct_member = true:suggestion
+
+# Предпочтения для блоков кода
+csharp_prefer_braces = when_multiline:silent
+csharp_prefer_simple_using_statement = true:suggestion
+csharp_prefer_system_threading_lock = true:suggestion
+csharp_style_namespace_declarations = file_scoped:silent
+csharp_style_prefer_method_group_conversion = true:silent
+csharp_style_prefer_primary_constructors = true:suggestion
+csharp_style_prefer_top_level_statements = false:silent
+
+# Выражения уровень предпочтения
+csharp_prefer_simple_default_expression = true:suggestion
+csharp_style_deconstructed_variable_declaration = true:suggestion
+csharp_style_implicit_object_creation_when_type_is_apparent = true:suggestion
+csharp_style_inlined_variable_declaration = true:suggestion
+csharp_style_prefer_index_operator = true:suggestion
+csharp_style_prefer_local_over_anonymous_function = true:suggestion
+csharp_style_prefer_null_check_over_type_check = true:suggestion
+csharp_style_prefer_range_operator = true:suggestion
+csharp_style_prefer_tuple_swap = true:suggestion
+csharp_style_prefer_unbound_generic_type_in_nameof = true:suggestion
+csharp_style_prefer_utf8_string_literals = true:suggestion
+csharp_style_throw_expression = true:suggestion
+csharp_style_unused_value_assignment_preference = discard_variable:suggestion
+csharp_style_unused_value_expression_statement_preference = discard_variable:silent
+
+# предпочтения для директивы using
+csharp_using_directive_placement = outside_namespace:silent
+
+# Предпочтения для новых строк
+csharp_style_allow_blank_line_after_colon_in_constructor_initializer_experimental = true:silent
+csharp_style_allow_blank_line_after_token_in_arrow_expression_clause_experimental = true:silent
+csharp_style_allow_blank_line_after_token_in_conditional_expression_experimental = true:silent
+csharp_style_allow_blank_lines_between_consecutive_braces_experimental = false:silent
+csharp_style_allow_embedded_statements_on_same_line_experimental = false:silent
+
+#### Правила форматирования C# ####
+
+# Предпочтения для новых строк
+csharp_new_line_before_catch = true
+csharp_new_line_before_else = true
+csharp_new_line_before_finally = true
+csharp_new_line_before_members_in_anonymous_types = true
+csharp_new_line_before_members_in_object_initializers = true
+csharp_new_line_before_open_brace = all
+csharp_new_line_between_query_expression_clauses = true
+
+# Предпочтения для отступов
+csharp_indent_block_contents = true
+csharp_indent_braces = false
+csharp_indent_case_contents = true
+csharp_indent_case_contents_when_block = true
+csharp_indent_labels = one_less_than_current
+csharp_indent_switch_labels = true
+
+# Предпочтения для интервалов
+csharp_space_after_cast = false
+csharp_space_after_colon_in_inheritance_clause = true
+csharp_space_after_comma = true
+csharp_space_after_dot = false
+csharp_space_after_keywords_in_control_flow_statements = true
+csharp_space_after_semicolon_in_for_statement = true
+csharp_space_around_binary_operators = before_and_after
+csharp_space_around_declaration_statements = false
+csharp_space_before_colon_in_inheritance_clause = true
+csharp_space_before_comma = false
+csharp_space_before_dot = false
+csharp_space_before_open_square_brackets = false
+csharp_space_before_semicolon_in_for_statement = false
+csharp_space_between_empty_square_brackets = false
+csharp_space_between_method_call_empty_parameter_list_parentheses = false
+csharp_space_between_method_call_name_and_opening_parenthesis = false
+csharp_space_between_method_call_parameter_list_parentheses = false
+csharp_space_between_method_declaration_empty_parameter_list_parentheses = false
+csharp_space_between_method_declaration_name_and_open_parenthesis = false
+csharp_space_between_method_declaration_parameter_list_parentheses = false
+csharp_space_between_parentheses = false
+csharp_space_between_square_brackets = false
+
+# Предпочтения переноса
+csharp_preserve_single_line_blocks = true
+csharp_preserve_single_line_statements = true
+
+#### Стили именования ####
+
+# Правила именования
+
+dotnet_naming_rule.interface_should_be_begins_with_i.severity = error
+dotnet_naming_rule.interface_should_be_begins_with_i.symbols = interface
+dotnet_naming_rule.interface_should_be_begins_with_i.style = begins_with_i
+
+dotnet_naming_rule.non_field_members_should_be_pascal_case.severity = error
+dotnet_naming_rule.non_field_members_should_be_pascal_case.symbols = non_field_members
+dotnet_naming_rule.non_field_members_should_be_pascal_case.style = pascal_case
+
+# Спецификации символов
+
+dotnet_naming_symbols.interface.applicable_kinds = interface
+dotnet_naming_symbols.interface.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.interface.required_modifiers = 
+
+dotnet_naming_symbols.types.applicable_kinds = class, struct, interface, enum
+dotnet_naming_symbols.types.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.types.required_modifiers = 
+
+dotnet_naming_symbols.non_field_members.applicable_kinds = property, event, method
+dotnet_naming_symbols.non_field_members.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.non_field_members.required_modifiers = 
+
+# Стили именования
+
+dotnet_naming_style.pascal_case.required_prefix = 
+dotnet_naming_style.pascal_case.required_suffix = 
+dotnet_naming_style.pascal_case.word_separator = 
+dotnet_naming_style.pascal_case.capitalization = pascal_case
+
+dotnet_naming_style.begins_with_i.required_prefix = I
+dotnet_naming_style.begins_with_i.required_suffix = 
+dotnet_naming_style.begins_with_i.word_separator = 
+dotnet_naming_style.begins_with_i.capitalization = pascal_case
+
+[*.{cs,vb}]
+dotnet_style_operator_placement_when_wrapping = beginning_of_line
+tab_width = 4
+indent_size = 4
+end_of_line = crlf
+dotnet_style_coalesce_expression = true:suggestion
+dotnet_style_null_propagation = true:suggestion
+dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion
+dotnet_style_prefer_auto_properties = true:silent
+dotnet_style_object_initializer = true:suggestion
+dotnet_style_collection_initializer = true:suggestion
+dotnet_style_prefer_simplified_boolean_expressions = true:suggestion
+dotnet_style_prefer_conditional_expression_over_assignment = true:silent
+dotnet_style_prefer_conditional_expression_over_return = true:silent
+dotnet_style_explicit_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion
+dotnet_style_prefer_compound_assignment = true:suggestion
+dotnet_style_prefer_simplified_interpolation = true:suggestion
+dotnet_style_prefer_collection_expression = when_types_loosely_match:suggestion
+dotnet_style_namespace_match_folder = true:suggestion
+dotnet_code_quality_unused_parameters = non_public:suggestion
+dotnet_style_predefined_type_for_member_access = true:silent
+dotnet_style_predefined_type_for_locals_parameters_members = true:silent
+dotnet_style_qualification_for_field = false:silent
+dotnet_style_qualification_for_property = false:silent
+dotnet_style_qualification_for_method = false:silent
+dotnet_style_qualification_for_event = false:silent
+dotnet_style_allow_multiple_blank_lines_experimental = true:silent
+dotnet_style_allow_statement_immediately_after_block_experimental = false:silent
+dotnet_style_readonly_field = true:suggestion
+dotnet_style_parentheses_in_arithmetic_binary_operators = always_for_clarity:silent
+dotnet_style_parentheses_in_other_binary_operators = always_for_clarity:silent
+dotnet_style_parentheses_in_other_operators = never_if_unnecessary:silent
+dotnet_style_parentheses_in_relational_binary_operators = always_for_clarity:silent
+dotnet_style_require_accessibility_modifiers = for_non_interface_members:silent

ApiDto/Requests/CreateUserRequest.cs

@@ -11,17 +11,20 @@ public class CreateUserRequest
     /// Gets or sets the email address of the user.
     /// </summary>
     [Required]
+    [EmailAddress]
     public required string Email { get; set; }
 
     /// <summary>
     /// Gets or sets the username of the user.
     /// </summary>
     [Required]
+    [MinLength(2)]
     public required string Username { get; set; }
 
     /// <summary>
     /// Gets or sets the password of the user.
     /// </summary>
     [Required]
+    [MinLength(2)]
     public required string Password { get; set; }
 }

Backend.sln

@@ -8,6 +8,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Elements of the solution", "Elements of the solution", "{3E087889-A4A0-4A55-A07D-7D149A5BC928}"
 	ProjectSection(SolutionItems) = preProject
 		.dockerignore = .dockerignore
+		.editorconfig = .editorconfig
 		.env = .env
 		.gitattributes = .gitattributes
 		.gitignore = .gitignore

Endpoint/Common/Attributes/CacheMaxAgeAttribute.cs

@@ -2,7 +2,7 @@
 
 namespace Mirea.Api.Endpoint.Common.Attributes;
 
-[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, Inherited = false)]
 public class CacheMaxAgeAttribute : Attribute
 {
     public int MaxAge { get; }

Endpoint/Common/Attributes/TokenAuthenticationAttribute.cs

@@ -13,7 +13,7 @@ public class TokenAuthenticationAttribute : Attribute, IActionFilter
     public void OnActionExecuting(ActionExecutingContext context)
     {
         var setupToken = context.HttpContext.RequestServices.GetRequiredService<ISetupToken>();
-        if (!context.HttpContext.Request.Cookies.TryGetValue(AuthToken, out string? tokenFromCookie))
+        if (!context.HttpContext.Request.Cookies.TryGetValue(AuthToken, out var tokenFromCookie))
         {
             context.Result = new UnauthorizedResult();
             return;

Endpoint/Common/Interfaces/IMaintenanceModeNotConfigureService.cs

@@ -3,6 +3,5 @@
 public interface IMaintenanceModeNotConfigureService
 {
     bool IsMaintenanceMode { get; }
-
     void DisableMaintenanceMode();
 }

Endpoint/Common/Interfaces/IMaintenanceModeService.cs

@@ -3,8 +3,6 @@
 public interface IMaintenanceModeService
 {
     bool IsMaintenanceMode { get; }
-
     void EnableMaintenanceMode();
-
     void DisableMaintenanceMode();
 }

Endpoint/Common/MapperDto/AvailableProvidersConverter.cs

@@ -17,7 +17,7 @@ public static class AvailableProvidersConverter
             _ => throw new ArgumentOutOfRangeException(nameof(provider), provider, null)
         };
 
-    public static List<AvailableOAuthProvidersResponse> ConvertToDto(this (OAuthProvider Provider, Uri Redirect)[] data) =>
+    public static List<AvailableOAuthProvidersResponse> ConvertToDto(this IEnumerable<(OAuthProvider Provider, Uri Redirect)> data) =>
         data.Select(x => new AvailableOAuthProvidersResponse()
         {
             ProviderName = Enum.GetName(x.Provider)!,

Endpoint/Common/MapperDto/PairPeriodTimeConverter.cs

@@ -9,5 +9,6 @@ public static class PairPeriodTimeConverter
     public static Dictionary<int, Dto.Common.PairPeriodTime> ConvertToDto(this IDictionary<int, ScheduleSettings.PairPeriodTime> pairPeriod) =>
     pairPeriod.ToDictionary(kvp => kvp.Key, kvp => new Dto.Common.PairPeriodTime { Start = kvp.Value.Start, End = kvp.Value.End });
 
-    public static Dictionary<int, ScheduleSettings.PairPeriodTime> ConvertFromDto(this IDictionary<int, Dto.Common.PairPeriodTime> pairPeriod) => pairPeriod.ToDictionary(kvp => kvp.Key, kvp => new ScheduleSettings.PairPeriodTime(kvp.Value.Start, kvp.Value.End));
+    public static Dictionary<int, ScheduleSettings.PairPeriodTime> ConvertFromDto(this IDictionary<int, Dto.Common.PairPeriodTime> pairPeriod) =>
+        pairPeriod.ToDictionary(kvp => kvp.Key, kvp => new ScheduleSettings.PairPeriodTime(kvp.Value.Start, kvp.Value.End));
 }

Endpoint/Common/Services/Security/DistributedCacheService.cs

@@ -9,7 +9,8 @@ namespace Mirea.Api.Endpoint.Common.Services.Security;
 
 public class DistributedCacheService(IDistributedCache cache) : ICacheService
 {
-    public async Task SetAsync<T>(string key, T value, TimeSpan? absoluteExpirationRelativeToNow = null, TimeSpan? slidingExpiration = null, CancellationToken cancellationToken = default)
+    public async Task SetAsync<T>(string key, T value, TimeSpan? absoluteExpirationRelativeToNow = null, TimeSpan? slidingExpiration = null,
+        CancellationToken cancellationToken = default)
     {
         var options = new DistributedCacheEntryOptions
         {

Endpoint/Common/Services/Security/MemoryCacheService.cs

@@ -9,7 +9,8 @@ namespace Mirea.Api.Endpoint.Common.Services.Security;
 
 public class MemoryCacheService(IMemoryCache cache) : ICacheService
 {
-    public Task SetAsync<T>(string key, T value, TimeSpan? absoluteExpirationRelativeToNow = null, TimeSpan? slidingExpiration = null, CancellationToken cancellationToken = default)
+    public Task SetAsync<T>(string key, T value, TimeSpan? absoluteExpirationRelativeToNow = null, TimeSpan? slidingExpiration = null,
+        CancellationToken cancellationToken = default)
     {
         var options = new MemoryCacheEntryOptions
         {

Endpoint/Configuration/Core/BackgroundTasks/ScheduleSyncService.cs

@@ -32,7 +32,7 @@ public class ScheduleSyncService : IHostedService, IDisposable
 
     private void OnForceSyncRequested()
     {
-        StopAsync(default).ContinueWith(_ =>
+        StopAsync(CancellationToken.None).ContinueWith(_ =>
         {
             _cancellationTokenSource = new CancellationTokenSource();
             ExecuteTask(null);
@@ -41,9 +41,9 @@ public class ScheduleSyncService : IHostedService, IDisposable
 
     private void OnUpdateIntervalRequested()
     {
-        StopAsync(default).ContinueWith(_ =>
+        StopAsync(CancellationToken.None).ContinueWith(_ =>
         {
-            StartAsync(default);
+            StartAsync(CancellationToken.None);
         });
     }
 
@@ -109,7 +109,7 @@ public class ScheduleSyncService : IHostedService, IDisposable
 
     public void Dispose()
     {
-        StopAsync(default).GetAwaiter().GetResult();
+        StopAsync(CancellationToken.None).GetAwaiter().GetResult();
         _timer?.Dispose();
         ScheduleSyncManager.OnForceSyncRequested -= OnForceSyncRequested;
         ScheduleSyncManager.OnUpdateIntervalRequested -= OnUpdateIntervalRequested;

Endpoint/Configuration/Core/Startup/EnvironmentConfiguration.cs

@@ -21,7 +21,7 @@ public static class EnvironmentConfiguration
 
             var commentIndex = line.IndexOf('#', StringComparison.Ordinal);
 
-            string arg = line;
+            var arg = line;
 
             if (commentIndex != -1)
                 arg = arg.Remove(commentIndex, arg.Length - commentIndex);

Endpoint/Configuration/Core/Startup/JwtConfiguration.cs

@@ -19,12 +19,14 @@ public static class JwtConfiguration
         var jwtDecrypt = Encoding.UTF8.GetBytes(configuration["SECURITY_ENCRYPTION_TOKEN"] ?? string.Empty);
 
         if (jwtDecrypt.Length != 32)
-            throw new InvalidOperationException("The secret token \"SECURITY_ENCRYPTION_TOKEN\" cannot be less than 32 characters long. Now the size is equal is " + jwtDecrypt.Length);
+            throw new InvalidOperationException("The secret token \"SECURITY_ENCRYPTION_TOKEN\" cannot be less than 32 characters long. " +
+                                                "Now the size is equal is " + jwtDecrypt.Length);
 
         var jwtKey = Encoding.UTF8.GetBytes(configuration["SECURITY_SIGNING_TOKEN"] ?? string.Empty);
 
         if (jwtKey.Length != 64)
-            throw new InvalidOperationException("The signature token \"SECURITY_SIGNING_TOKEN\" cannot be less than 64 characters. Now the size is " + jwtKey.Length);
+            throw new InvalidOperationException("The signature token \"SECURITY_SIGNING_TOKEN\" cannot be less than 64 characters. " +
+                                                "Now the size is " + jwtKey.Length);
 
         var jwtIssuer = configuration["SECURITY_JWT_ISSUER"];
         var jwtAudience = configuration["SECURITY_JWT_AUDIENCE"];

Endpoint/Configuration/Core/Startup/SwaggerConfiguration.cs

@@ -19,6 +19,7 @@ public static class SwaggerConfiguration
         {
             options.SchemaFilter<SwaggerExampleFilter>();
             options.OperationFilter<SwaggerDefaultValues>();
+            options.OperationFilter<ActionResultSchemaFilter>();
             var basePath = AppDomain.CurrentDomain.BaseDirectory;
 
             options.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme

Endpoint/Configuration/Model/Admin.cs

@@ -10,12 +10,22 @@ namespace Mirea.Api.Endpoint.Configuration.Model;
 public class Admin : ISaveSettings
 {
     [JsonIgnore] private const string FileName = "admin.json";
+    private string _username = string.Empty;
+    private string _email = string.Empty;
 
     [JsonIgnore]
     public static string FilePath => PathBuilder.Combine(FileName);
 
-    public required string Username { get; set; }
-    public required string Email { get; set; }
+    public required string Username
+    {
+        get => _username;
+        set => _username = value.Trim();
+    }
+    public required string Email
+    {
+        get => _email;
+        set => _email = value.Trim();
+    }
     public required string PasswordHash { get; set; }
     public required string Salt { get; set; }
     public TwoFactorAuthenticator TwoFactorAuthenticator { get; set; } = TwoFactorAuthenticator.None;

Endpoint/Configuration/SwaggerOptions/ActionResultSchemaFilter.cs

@@ -0,0 +1,81 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.OpenApi.Models;
+using Swashbuckle.AspNetCore.SwaggerGen;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Mirea.Api.Endpoint.Configuration.SwaggerOptions;
+
+public class ActionResultSchemaFilter : IOperationFilter
+{
+    public void Apply(OpenApiOperation operation, OperationFilterContext context)
+    {
+        var returnType = context.MethodInfo.ReturnType;
+        if (!returnType.IsEquivalentTo(typeof(ActionResult)) &&
+            !returnType.IsEquivalentTo(typeof(ContentResult)) &&
+            !returnType.IsEquivalentTo(typeof(FileStreamResult)) &&
+            !returnType.IsGenericType)
+            return;
+
+        if (returnType.IsGenericType &&
+            !returnType.GetGenericTypeDefinition().IsEquivalentTo(typeof(ActionResult<>)) &&
+            !returnType.GetGenericTypeDefinition().IsEquivalentTo(typeof(Task<>)))
+            return;
+
+        var genericType = returnType.IsGenericType ? returnType.GetGenericArguments().FirstOrDefault() : returnType;
+        if (genericType == null)
+            return;
+
+        var responseTypeAttributes = context.MethodInfo.GetCustomAttributes(typeof(ProducesResponseTypeAttribute), false)
+            .Cast<ProducesResponseTypeAttribute>()
+            .Where(attr => attr.StatusCode == 200)
+            .ToList();
+
+        var contentType = "application/json";
+
+        if (context.MethodInfo.GetCustomAttributes(typeof(ProducesAttribute), false)
+            .FirstOrDefault() is ProducesAttribute producesAttribute)
+            contentType = producesAttribute.ContentTypes.FirstOrDefault() ?? "application/json";
+
+        if (responseTypeAttributes.Count != 0)
+        {
+            var responseType = responseTypeAttributes.First().Type;
+            genericType = responseType;
+        }
+
+        if (genericType.IsEquivalentTo(typeof(ContentResult)) || genericType.IsEquivalentTo(typeof(FileStreamResult)))
+        {
+            operation.Responses["200"] = new OpenApiResponse
+            {
+                Description = "OK",
+                Content = new Dictionary<string, OpenApiMediaType>
+                {
+                    [contentType] = new()
+                }
+            };
+        }
+        else if (genericType == typeof(ActionResult))
+        {
+            operation.Responses["200"] = new OpenApiResponse { Description = "OK" };
+        }
+        else
+        {
+            OpenApiSchema schema;
+            if (genericType.IsGenericType && genericType.GetGenericTypeDefinition() == typeof(ActionResult<>))
+                schema = context.SchemaGenerator.GenerateSchema(genericType.GetGenericArguments().FirstOrDefault(),
+                    context.SchemaRepository);
+            else
+                schema = context.SchemaGenerator.GenerateSchema(genericType, context.SchemaRepository);
+
+            operation.Responses["200"] = new OpenApiResponse
+            {
+                Description = "OK",
+                Content = new Dictionary<string, OpenApiMediaType>
+                {
+                    [contentType] = new() { Schema = schema }
+                }
+            };
+        }
+    }
+}

Endpoint/Configuration/SwaggerOptions/ConfigureSwaggerOptions.cs

@@ -23,7 +23,8 @@ public class ConfigureSwaggerOptions(IApiVersionDescriptionProvider provider) :
         {
             Title = "MIREA Schedule Web API",
             Version = description.ApiVersion.ToString(),
-            Description = "This API provides a convenient interface for retrieving data stored in the database. Special attention was paid to the lightweight and easy transfer of all necessary data. Made by the Winsomnia team.",
+            Description = "This API provides a convenient interface for retrieving data stored in the database. " +
+                          "Special attention was paid to the lightweight and easy transfer of all necessary data. Made by the Winsomnia team.",
             Contact = new OpenApiContact { Name = "Author name", Email = "support@winsomnia.net" },
             License = new OpenApiLicense { Name = "MIT", Url = new Uri("https://opensource.org/licenses/MIT") }
         };

Endpoint/Configuration/Validation/SetupTokenService.cs

@@ -14,8 +14,8 @@ public class SetupTokenService : ISetupToken
 
         var token2 = Token.Value.Span;
 
-        int result = 0;
-        for (int i = 0; i < Token.Value.Length; i++)
+        var result = 0;
+        for (var i = 0; i < Token.Value.Length; i++)
             result |= token2[i] ^ token[i];
 
         return result == 0;

Endpoint/Controllers/Configuration/SetupController.cs

@@ -29,7 +29,6 @@ using System.Collections.Generic;
 using System.Data;
 using System.IO;
 using System.Linq;
-using System.Net.Mail;
 using System.Runtime.InteropServices;
 using System.Security;
 using System.Security.Cryptography;
@@ -144,7 +143,7 @@ public class SetupController(
     [BadRequestResponse]
     public ActionResult<bool> SetPsql([FromBody] DatabaseRequest request)
     {
-        string connectionString = $"Host={request.Server}:{request.Port};Username={request.User};Database={request.Database}";
+        var connectionString = $"Host={request.Server}:{request.Port};Username={request.User};Database={request.Database}";
         if (request.Password != null)
             connectionString += $";Password={request.Password}";
         if (request.Ssl)
@@ -171,7 +170,7 @@ public class SetupController(
     [BadRequestResponse]
     public ActionResult<bool> SetMysql([FromBody] DatabaseRequest request)
     {
-        string connectionString = $"Server={request.Server}:{request.Port};Uid={request.User};Database={request.Database};";
+        var connectionString = $"Server={request.Server}:{request.Port};Uid={request.User};Database={request.Database};";
         if (request.Password != null)
             connectionString += $"Pwd={request.Password};";
         if (request.Ssl)
@@ -241,7 +240,7 @@ public class SetupController(
     [BadRequestResponse]
     public ActionResult<bool> SetRedis([FromBody] CacheRequest request)
     {
-        string connectionString = $"{request.Server}:{request.Port},ssl=false";
+        var connectionString = $"{request.Server}:{request.Port},ssl=false";
         if (request.Password != null)
             connectionString += $",password={request.Password}";
 
@@ -305,10 +304,6 @@ public class SetupController(
     public ActionResult<string> CreateAdmin([FromBody] CreateUserRequest userRequest)
     {
         new PasswordPolicyService(GeneralConfig.PasswordPolicy).ValidatePasswordOrThrow(userRequest.Password);
-
-        if (!MailAddress.TryCreate(userRequest.Email, out _))
-            throw new ControllerArgumentException("The email address is incorrect.");
-
         var (salt, hash) = passwordHashService.HashPassword(userRequest.Password);
 
         var admin = new Admin

Endpoint/Controllers/V1/AuthController.cs

@@ -16,14 +16,15 @@ using Mirea.Api.Security.Services;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Security.Claims;
+using System.Linq;
 using System.Threading.Tasks;
 using OAuthProvider = Mirea.Api.Security.Common.Domain.OAuthProvider;
 
 namespace Mirea.Api.Endpoint.Controllers.V1;
 
 [ApiVersion("1.0")]
-public class AuthController(IOptionsSnapshot<Admin> user, IOptionsSnapshot<GeneralConfig> generalConfig, AuthService auth, PasswordHashService passwordService, OAuthService oAuthService) : BaseController
+public class AuthController(IOptionsSnapshot<Admin> user, IOptionsSnapshot<GeneralConfig> generalConfig, AuthService auth,
+    PasswordHashService passwordService, OAuthService oAuthService) : BaseController
 {
     private CookieOptionsParameters GetCookieParams() =>
         new()
@@ -32,94 +33,73 @@ public class AuthController(IOptionsSnapshot<Admin> user, IOptionsSnapshot<Gener
             Path = UrlHelper.GetSubPathWithoutFirstApiName + "api"
         };
 
-    private static string GenerateHtmlResponse(string title, string message, OAuthProvider? provider, bool isError = false, string? traceId = null)
+    private static string GenerateHtmlResponse(
+        string title,
+        string message,
+        Uri? callback,
+        string traceId,
+        bool isError)
     {
-        string messageColor = isError ? "red" : "white";
-        string script = "<script>setTimeout(()=>{if(window.opener){window.opener.postMessage(" +
-                        "{success:" + (!isError).ToString().ToLower() +
-                        ",provider:'" + (provider == null ? "null" : (int)provider) +
-                        "',providerName:'" + (provider == null ? "null" : Enum.GetName(provider.Value)) +
-                        "',message:'" + message.Replace("'", "\\'") +
-                        "'},'*');}window.close();}, 15000);</script>";
+        var callbackUrl = callback?.ToString();
 
-        return $"<!DOCTYPE html><html lang=ru><head><meta charset=UTF-8><meta content=\"width=device-width,initial-scale=1\"name=viewport><link href=\"https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap\"rel=stylesheet><style>body{{background-color:#121212;color:#fff;font-family:Roboto,sans-serif;display:flex;justify-content:center;align-items:center;height:100vh;margin:0;text-align:center}}.container{{max-width:600px;padding:20px;border-radius:8px;background-color:#1e1e1e;box-shadow:0 4px 20px rgba(0,0,0,.5)}}h1{{font-size:24px;margin-bottom:20px}}p{{font-size:16px;color:{messageColor}}}</style><title>{title}</title></head><body><div class=container><h1>{title}</h1><p>{message}</p><p style=font-size:14px;color:silver;>Это информационная страница. Вы можете закрыть её.</p>{(!string.IsNullOrEmpty(traceId) ? $"<code style=font-size:12px;color:gray;>TraceId={traceId}</code>" : string.Empty)}</div>{script}</body></html>";
+        var script = callback == null ? string.Empty :
+            $"<script>setTimeout(()=>{{window.location.href='{callbackUrl}';}}, {(isError ? 15000 : 5000)});</script>";
+
+        var blockInfo = "<p>" + (callback == null ?
+            "Вернитесь обратно и попробуйте снова позже.</p>" :
+            $"Если вы не будете автоматически перенаправлены, нажмите ниже.</p>" +
+            $"<a href=\"{callbackUrl}\" style=\"color:inherit;text-decoration:underline;\">Перейти вручную</a>");
+
+        return $"<!DOCTYPE html><html lang=ru><head><meta charset=UTF-8><meta content=\"width=device-width,initial-scale=1\"name=viewport><link href=\"https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap\"rel=stylesheet><style>body{{background-color:#121212;color:#fff;font-family:Roboto,sans-serif;display:flex;justify-content:center;align-items:center;height:100vh;margin:0;text-align:center}}.container{{max-width:600px;padding:20px;border-radius:8px;background-color:#1e1e1e;box-shadow:0 4px 20px rgba(0,0,0,.5)}}h1{{font-size:24px;margin-bottom:20px}}</style><title>{title}</title></head><body><div class=container><h1>{title}</h1>{blockInfo}<p style=font-size:14px;color:silver;>{message}</p><code style=font-size:12px;color:gray;>TraceId={traceId}</code></div>{script}</body></html>";
     }
 
     [HttpGet("OAuth2")]
     [BadRequestResponse]
-    [ProducesResponseType(typeof(string), StatusCodes.Status200OK)]
     [Produces("text/html")]
     [MaintenanceModeIgnore]
-    public async Task<ContentResult> OAuth2([FromQuery] string code, [FromQuery] string state)
+    public async Task<ContentResult> OAuth2([FromQuery] string? code, [FromQuery] string? state)
     {
-        var userId = HttpContext.User.FindFirstValue(ClaimTypes.NameIdentifier);
-        string title;
-        string message;
-        OAuthProvider provider;
-        OAuthUser oAuthUser;
         var traceId = Activity.Current?.Id ?? HttpContext.TraceIdentifier;
 
-        try
-        {
-            (provider, oAuthUser) = await oAuthService.LoginOAuth(HttpContext, GetCookieParams(),
+        if (string.IsNullOrEmpty(code) || string.IsNullOrEmpty(state))
+            return Content(GenerateHtmlResponse(
+                "Ошибка передачи данных!",
+                "Провайдер OAuth не передал нужных данных.",
+                null,
+                traceId,
+                true), "text/html");
+
+        var result = await oAuthService.LoginOAuth(HttpContext, GetCookieParams(),
                 HttpContext.GetApiUrl(Url.Action("OAuth2")!), code, state);
-        }
-        catch (Exception e)
+
+        string? callbackUrl = null;
+
+        if (result.Callback != null)
+            callbackUrl = result.Callback + (result.Callback.Query.Length > 0 ? "&" : "?") +
+                          $"result={Uri.EscapeDataString(result.Token)}";
+
+        string title, message;
+
+        if (!result.Success)
         {
-            title = "Произошла ошибка при общении с провайдером OAuth!";
-            message = e.Message;
-            return Content(GenerateHtmlResponse(title, message, null, true, traceId), "text/html");
+            if (callbackUrl != null)
+                callbackUrl += $"&traceId={Uri.EscapeDataString(traceId)}";
+
+            title = "Ошибка авторизации!";
+            message = result.ErrorMessage ?? "Произошла ошибка. Попробуйте ещё раз.";
         }
-
-        var userEntity = user.Value;
-
-        if (userId != null)
+        else
         {
-            userEntity.OAuthProviders ??= [];
-
-            if (!userEntity.OAuthProviders.TryAdd(provider, oAuthUser))
-            {
-                title = "Ошибка связи аккаунта!";
-                message = "Этот OAuth провайдер уже связан с вашей учетной записью. Пожалуйста, используйте другого провайдера или удалите связь с аккаунтом.";
-                return Content(GenerateHtmlResponse(title, message, provider, true, traceId), "text/html");
-            }
-
-            userEntity.SaveSetting();
-
-            title = "Учетная запись успешно связана.";
-            message = "Вы успешно связали свою учетную запись с провайдером OAuth. Вы можете продолжить использовать приложение.";
-            return Content(GenerateHtmlResponse(title, message, provider), "text/html");
+            title = "Авторизация завершена!";
+            message = "Вы будете перенаправлены обратно через несколько секунд.";
         }
 
-        if (userEntity.OAuthProviders != null &&
-            userEntity.OAuthProviders.TryGetValue(provider, out var userOAuth) &&
-            userOAuth.Id == oAuthUser.Id)
-        {
-            await auth.LoginOAuthAsync(GetCookieParams(), HttpContext, new User
-            {
-                Id = 1.ToString(),
-                Username = userEntity.Username,
-                Email = userEntity.Email,
-                PasswordHash = userEntity.PasswordHash,
-                Salt = userEntity.Salt,
-                TwoFactorAuthenticator = userEntity.TwoFactorAuthenticator,
-                SecondFactorToken = userEntity.Secret,
-                OAuthProviders = userEntity.OAuthProviders
-            });
-
-            title = "Успешный вход в аккаунт.";
-            message = "Вы успешно вошли в свою учетную запись. Добро пожаловать!";
-            return Content(GenerateHtmlResponse(title, message, provider), "text/html");
-        }
-
-        title = "Вы успешно зарегистрированы.";
-        message = "Процесс завершен. Вы можете закрыть эту страницу.";
-        userEntity.Email = string.IsNullOrEmpty(oAuthUser.Email) ? string.Empty : oAuthUser.Email;
-        userEntity.Username = string.IsNullOrEmpty(oAuthUser.Username) ? string.Empty : oAuthUser.Username;
-        userEntity.OAuthProviders ??= [];
-        userEntity.OAuthProviders.Add(provider, oAuthUser);
-        userEntity.SaveSetting();
-        return Content(GenerateHtmlResponse(title, message, provider), "text/html");
+        return Content(GenerateHtmlResponse(
+            title,
+            message,
+            callbackUrl == null ? null : new Uri(callbackUrl),
+            traceId,
+            !result.Success), "text/html");
     }
 
     /// <summary>
@@ -129,16 +109,23 @@ public class AuthController(IOptionsSnapshot<Admin> user, IOptionsSnapshot<Gener
     /// This method generates a redirect URL for the selected provider and redirects the user to it.
     /// </remarks>
     /// <param name="provider">The identifier of the OAuth provider to authorize with.</param>
+    /// <param name="callback">The address where the user will need to be redirected after the end of communication with the OAuth provider</param>
     /// <returns>A redirect to the OAuth provider's authorization URL.</returns>
     /// <exception cref="ControllerArgumentException">Thrown if the specified provider is not valid.</exception>
     [HttpGet("AuthorizeOAuth2")]
     [MaintenanceModeIgnore]
-    public ActionResult AuthorizeOAuth2([FromQuery] int provider)
+    public ActionResult AuthorizeOAuth2([FromQuery] int provider, [FromQuery] Uri callback)
     {
         if (!Enum.IsDefined(typeof(OAuthProvider), provider))
             throw new ControllerArgumentException("There is no selected provider");
 
-        return Redirect(oAuthService.GetProviderRedirect(HttpContext, GetCookieParams(), HttpContext.GetApiUrl(Url.Action("OAuth2")!), (OAuthProvider)provider).AbsoluteUri);
+        if (!callback.IsAbsoluteUri)
+            throw new ControllerArgumentException("The callback URL must be absolute.");
+
+        return Redirect(oAuthService.GetProviderRedirect(HttpContext, GetCookieParams(),
+            HttpContext.GetApiUrl(Url.Action("OAuth2")!),
+            (OAuthProvider)provider,
+            callback).AbsoluteUri);
     }
 
     /// <summary>
@@ -150,9 +137,17 @@ public class AuthController(IOptionsSnapshot<Admin> user, IOptionsSnapshot<Gener
     /// <returns>A list of available providers and their redirect URLs.</returns>
     [HttpGet("AvailableProviders")]
     [MaintenanceModeIgnore]
-    public ActionResult<List<AvailableOAuthProvidersResponse>> AvailableProviders() =>
+    public ActionResult<List<AvailableOAuthProvidersResponse>> AvailableProviders([FromQuery] Uri callback) =>
         Ok(oAuthService
             .GetAvailableProviders(HttpContext.GetApiUrl(Url.Action("AuthorizeOAuth2")!))
+            .Select(x =>
+            {
+                if (!callback.IsAbsoluteUri)
+                    throw new ControllerArgumentException("The callback URL must be absolute.");
+
+                x.Redirect = new Uri(x.Redirect + "&callback=" + Uri.EscapeDataString(callback.AbsoluteUri));
+                return x;
+            })
             .ConvertToDto());
 
     /// <summary>

Endpoint/Controllers/V1/DisciplineController.cs

@@ -24,7 +24,8 @@ public class DisciplineController(IMediator mediator) : BaseController
     /// <returns>Paginated list of disciplines.</returns>
     [HttpGet]
     [BadRequestResponse]
-    public async Task<ActionResult<List<DisciplineResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page, [FromQuery][Range(1, int.MaxValue)] int? pageSize)
+    public async Task<ActionResult<List<DisciplineResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page,
+        [FromQuery][Range(1, int.MaxValue)] int? pageSize)
     {
         var result = await mediator.Send(new GetDisciplineListQuery()
         {

Endpoint/Controllers/V1/FacultyController.cs

@@ -23,7 +23,8 @@ public class FacultyController(IMediator mediator) : BaseController
     /// <returns>Paginated list of faculties.</returns>
     [HttpGet]
     [BadRequestResponse]
-    public async Task<ActionResult<List<FacultyResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page, [FromQuery][Range(1, int.MaxValue)] int? pageSize)
+    public async Task<ActionResult<List<FacultyResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page,
+        [FromQuery][Range(1, int.MaxValue)] int? pageSize)
     {
         var result = await mediator.Send(new GetFacultyListQuery()
         {

Endpoint/Controllers/V1/GroupController.cs

@@ -38,7 +38,8 @@ public class GroupController(IMediator mediator) : BaseController
     /// <returns>A list of groups.</returns>
     [HttpGet]
     [BadRequestResponse]
-    public async Task<ActionResult<List<GroupResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page, [FromQuery][Range(1, int.MaxValue)] int? pageSize)
+    public async Task<ActionResult<List<GroupResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page,
+        [FromQuery][Range(1, int.MaxValue)] int? pageSize)
     {
         var result = await mediator.Send(new GetGroupListQuery()
         {

Endpoint/Controllers/V1/ImportController.cs

@@ -40,7 +40,7 @@ public class ImportController(IMediator mediator, IOptionsSnapshot<GeneralConfig
     /// <returns>Excel file</returns>
     [HttpPost("ImportToExcel")]
     [Produces("application/vnd.ms-excel")]
-    public async Task<IActionResult> ImportToExcel([FromBody] ScheduleRequest request)
+    public async Task<FileStreamResult> ImportToExcel([FromBody] ScheduleRequest request)
     {
         var result = (await mediator.Send(new GetScheduleListQuery
         {
@@ -49,17 +49,14 @@ public class ImportController(IMediator mediator, IOptionsSnapshot<GeneralConfig
             GroupIds = request.Groups,
             LectureHallIds = request.LectureHalls,
             ProfessorIds = request.Professors
-        })).Schedules;
-
-        if (result.Count == 0)
-            return NoContent();
+        })).Schedules.ToList();
 
         ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
         using var package = new ExcelPackage();
         var worksheet = package.Workbook.Worksheets.Add("Расписание");
 
-        int row = 1;
-        int col = 1;
+        var row = 1;
+        var col = 1;
 
         worksheet.Cells[row, col++].Value = "День";
         worksheet.Cells[row, col++].Value = "Пара";

Endpoint/Controllers/V1/ProfessorController.cs

@@ -26,7 +26,8 @@ public class ProfessorController(IMediator mediator) : BaseController
     /// <returns>A list of professors.</returns>
     [HttpGet]
     [BadRequestResponse]
-    public async Task<ActionResult<List<ProfessorResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page, [FromQuery][Range(1, int.MaxValue)] int? pageSize)
+    public async Task<ActionResult<List<ProfessorResponse>>> Get([FromQuery][Range(0, int.MaxValue)] int? page,
+        [FromQuery][Range(1, int.MaxValue)] int? pageSize)
     {
         var result = await mediator.Send(new GetProfessorListQuery()
         {

Endpoint/Controllers/V1/ScheduleController.cs

@@ -66,7 +66,7 @@ public class ScheduleController(IMediator mediator, IOptionsSnapshot<GeneralConf
             GroupIds = request.Groups,
             LectureHallIds = request.LectureHalls,
             ProfessorIds = request.Professors
-        })).Schedules;
+        })).Schedules.ToList();
 
         if (result.Count == 0)
             NoContent();

Endpoint/Controllers/V1/SecurityController.cs

@@ -28,7 +28,7 @@ public class SecurityController(IOptionsSnapshot<GeneralConfig> generalConfig) :
     [HttpGet("GenerateTotpQrCode")]
     [Produces("image/svg+xml")]
     [MaintenanceModeIgnore]
-    public IActionResult GenerateTotpQrCode(
+    public ContentResult GenerateTotpQrCode(
         [FromQuery] string totpKey,
         [FromQuery] string label,
         [FromQuery] string? backgroundColor = null,

Endpoint/Sync/ScheduleSynchronizer.cs

@@ -19,7 +19,8 @@ using Group = Mirea.Api.DataAccess.Domain.Schedule.Group;
 
 namespace Mirea.Api.Endpoint.Sync;
 
-internal partial class ScheduleSynchronizer(UberDbContext dbContext, IOptionsSnapshot<GeneralConfig> config, ILogger<ScheduleSynchronizer> logger, IMaintenanceModeService maintenanceMode)
+internal partial class ScheduleSynchronizer(UberDbContext dbContext, IOptionsSnapshot<GeneralConfig> config, ILogger<ScheduleSynchronizer> logger,
+    IMaintenanceModeService maintenanceMode)
 {
     private readonly DataRepository<Campus> _campuses = new([.. dbContext.Campuses]);
     private readonly DataRepository<Discipline> _disciplines = new([.. dbContext.Disciplines]);
@@ -120,7 +121,7 @@ internal partial class ScheduleSynchronizer(UberDbContext dbContext, IOptionsSna
         {
             hall = [];
             campuses = [];
-            for (int i = 0; i < groupInfo.Campuses.Length; i++)
+            for (var i = 0; i < groupInfo.Campuses.Length; i++)
             {
                 var campus = groupInfo.Campuses[i];
                 campuses.Add(_campuses.GetOrCreate(
@@ -151,7 +152,7 @@ internal partial class ScheduleSynchronizer(UberDbContext dbContext, IOptionsSna
                 Name = groupInfo.Discipline
             });
 
-        var lesson = _lessons.GetOrCreate(l =>
+        Lesson lesson = _lessons.GetOrCreate(l =>
                 l.IsEven == groupInfo.IsEven &&
                 l.DayOfWeek == groupInfo.Day &&
                 l.PairNumber == groupInfo.Pair &&
@@ -182,9 +183,9 @@ internal partial class ScheduleSynchronizer(UberDbContext dbContext, IOptionsSna
                 return lesson;
             });
 
-        int maxValue = int.Max(int.Max(professor?.Count ?? -1, hall?.Count ?? -1), 1);
+        var maxValue = int.Max(int.Max(professor?.Count ?? -1, hall?.Count ?? -1), 1);
 
-        for (int i = 0; i < maxValue; i++)
+        for (var i = 0; i < maxValue; i++)
         {
             var prof = professor?.ElementAtOrDefault(i);
             var lectureHall = hall?.ElementAtOrDefault(i);
@@ -226,7 +227,9 @@ internal partial class ScheduleSynchronizer(UberDbContext dbContext, IOptionsSna
 
         if (pairPeriods == null || startTerm == null)
         {
-            logger.LogWarning("It is not possible to synchronize the schedule due to the fact that the {Arg1} or {Arg2} variable is not initialized.", nameof(pairPeriods), nameof(startTerm));
+            logger.LogWarning("It is not possible to synchronize the schedule due to the fact that the {Arg1} or {Arg2} variable is not initialized.",
+                nameof(pairPeriods),
+                nameof(startTerm));
 
             return;
         }

Security/Common/Domain/LoginOAuthResult.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace Mirea.Api.Security.Common.Domain;
+
+public class LoginOAuthResult
+{
+    public bool Success { get; set; }
+    public required string Token { get; set; }
+    public Uri? Callback { get; set; }
+    public string? ErrorMessage { get; set; }
+}

Security/Common/Domain/OAuth2/OAuthPayload.cs

@@ -0,0 +1,7 @@
+namespace Mirea.Api.Security.Common.Domain.OAuth2;
+
+public class OAuthPayload
+{
+    public required OAuthProvider Provider { get; set; }
+    public required string Callback { get; set; }
+}

Security/Common/Domain/OAuth2/OAuthProviderUrisData.cs

@@ -2,7 +2,7 @@
 
 namespace Mirea.Api.Security.Common.Domain.OAuth2;
 
-internal struct OAuthProviderUrisData
+internal readonly struct OAuthProviderUrisData
 {
     public string RedirectUrl { get; init; }
     public string TokenUrl { get; init; }

Security/DependencyInjection.cs

@@ -6,11 +6,29 @@ using Mirea.Api.Security.Common.Interfaces;
 using Mirea.Api.Security.Services;
 using System;
 using System.Collections.Generic;
+using System.Text;
 
 namespace Mirea.Api.Security;
 
 public static class DependencyInjection
 {
+    private static ReadOnlyMemory<byte> NormalizeKey(string key, int requiredLength)
+    {
+        var keyBytes = Encoding.UTF8.GetBytes(key);
+
+        if (keyBytes.Length < requiredLength)
+        {
+            var normalizedKey = new byte[requiredLength];
+            Array.Copy(keyBytes, normalizedKey, keyBytes.Length);
+            return new ReadOnlyMemory<byte>(normalizedKey);
+        }
+
+        if (keyBytes.Length > requiredLength)
+            Array.Resize(ref keyBytes, requiredLength);
+
+        return new ReadOnlyMemory<byte>(keyBytes);
+    }
+
     public static IServiceCollection AddSecurityServices(this IServiceCollection services, IConfiguration configuration)
     {
         var saltSize = int.Parse(configuration["SECURITY_SALT_SIZE"]!);
@@ -61,7 +79,13 @@ public static class DependencyInjection
             providers.Add(provider, (clientId, secret));
         }
 
-        services.AddSingleton(provider => new OAuthService(provider.GetRequiredService<ILogger<OAuthService>>(), providers, configuration["SECURITY_ENCRYPTION_TOKEN"]!));
+        services.AddSingleton(provider => new OAuthService(
+            provider.GetRequiredService<ILogger<OAuthService>>(),
+            providers,
+            provider.GetRequiredService<ICacheService>())
+        {
+            SecretKey = NormalizeKey(configuration["SECURITY_ENCRYPTION_TOKEN"]!, 32)
+        });
 
         return services;
     }

Security/Services/AuthService.cs

@@ -12,7 +12,8 @@ using System.Threading.Tasks;
 
 namespace Mirea.Api.Security.Services;
 
-public class AuthService(ICacheService cache, IAccessToken accessTokenService, IRevokedToken revokedToken, ILogger<AuthService> logger, PasswordHashService passwordService)
+public class AuthService(ICacheService cache, IAccessToken accessTokenService, IRevokedToken revokedToken, ILogger<AuthService> logger,
+    PasswordHashService passwordService)
 {
     public TimeSpan Lifetime { private get; init; }
     public TimeSpan LifetimeFirstAuth { private get; init; }
@@ -24,15 +25,16 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
 
     private static string GetAuthCacheKey(string fingerprint) => $"{fingerprint}_auth_token";
     private static string GetFirstAuthCacheKey(string fingerprint) => $"{fingerprint}_auth_token_first";
+    private static string GetAttemptFailedCountKey(string fingerprint) => $"{fingerprint}_login_failed";
 
-    private Task SetAuthTokenDataToCache(AuthToken data, CancellationToken cancellation) =>
+    private Task StoreAuthTokenInCache(AuthToken data, CancellationToken cancellation) =>
         cache.SetAsync(
             GetAuthCacheKey(data.Fingerprint),
             JsonSerializer.SerializeToUtf8Bytes(data),
             slidingExpiration: Lifetime,
             cancellationToken: cancellation);
 
-    private Task CreateFirstAuthTokenToCache(User data, RequestContextInfo requestContext, CancellationToken cancellation) =>
+    private Task StoreFirstAuthTokenInCache(User data, RequestContextInfo requestContext, CancellationToken cancellation) =>
         cache.SetAsync(
             GetFirstAuthCacheKey(requestContext.Fingerprint),
             JsonSerializer.SerializeToUtf8Bytes(new FirstAuthToken(requestContext)
@@ -47,39 +49,53 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
     private Task RevokeAccessToken(string token) =>
         revokedToken.AddTokenToRevokedAsync(token, accessTokenService.GetExpireDateTime(token));
 
-    private async Task VerifyUserOrThrowError(RequestContextInfo requestContext, User user, string password, string username,
-        CancellationToken cancellation = default)
+    private async Task RecordFailedLoginAttempt(string fingerprint, string userId, CancellationToken cancellation)
     {
-        if ((user.Email.Equals(username, StringComparison.OrdinalIgnoreCase) || user.Username.Equals(username, StringComparison.OrdinalIgnoreCase)) &&
-            passwordService.VerifyPassword(password, user.Salt, user.PasswordHash))
-            return;
+        var failedLoginAttemptsCount = await cache.GetAsync<int?>(GetAttemptFailedCountKey(fingerprint), cancellation) ?? 1;
+        var failedLoginCacheExpiration = TimeSpan.FromHours(1);
 
-        var failedLoginCacheName = $"{requestContext.Fingerprint}_login_failed";
-        var countFailedLogin = await cache.GetAsync<int?>(failedLoginCacheName, cancellation) ?? 1;
-        var cacheSaveTime = TimeSpan.FromHours(1);
-
-        await cache.SetAsync(failedLoginCacheName, countFailedLogin + 1, slidingExpiration: cacheSaveTime, cancellationToken: cancellation);
-
-        if (countFailedLogin > 5)
+        if (failedLoginAttemptsCount > 5)
         {
             logger.LogWarning(
-                "Multiple unsuccessful login attempts for user ID {UserId}. Attempt count: {AttemptNumber}.",
-                user.Id,
-                countFailedLogin);
+                "Multiple unsuccessful login attempts for user ID {UserId}. Fingerprint: {Fingerprint}. Attempt count: {AttemptNumber}.",
+                userId,
+                fingerprint,
+                failedLoginAttemptsCount);
 
             throw new SecurityException("Too many unsuccessful login attempts. Please try again later.");
         }
 
         logger.LogInformation(
             "Login attempt failed for user ID {UserId}. Fingerprint: {Fingerprint}. Attempt count: {AttemptNumber}.",
-            user.Id,
-            requestContext.Fingerprint,
-            countFailedLogin);
+            userId,
+            fingerprint,
+            failedLoginAttemptsCount);
+
+        await cache.SetAsync(GetAttemptFailedCountKey(fingerprint), failedLoginAttemptsCount + 1,
+            slidingExpiration: failedLoginCacheExpiration, cancellationToken: cancellation);
+    }
+
+    private Task ResetFailedLoginAttempts(string fingerprint, CancellationToken cancellation) =>
+        cache.RemoveAsync(GetAttemptFailedCountKey(fingerprint), cancellation);
+
+    private async Task VerifyUserOrThrowError(RequestContextInfo requestContext, User user, string password, string username,
+        CancellationToken cancellation = default)
+    {
+        if ((user.Email.Equals(username, StringComparison.OrdinalIgnoreCase) ||
+             user.Username.Equals(username, StringComparison.OrdinalIgnoreCase)) &&
+            passwordService.VerifyPassword(password, user.Salt, user.PasswordHash))
+        {
+            await ResetFailedLoginAttempts(requestContext.Fingerprint, cancellation);
+            return;
+        }
+
+        await RecordFailedLoginAttempt(requestContext.Fingerprint, user.Id, cancellation);
 
         throw new SecurityException("Authentication failed. Please check your credentials.");
     }
 
-    private async Task GenerateAuthTokensAsync(CookieOptionsParameters cookieOptions, HttpContext context, RequestContextInfo requestContext, string userId, CancellationToken cancellation = default)
+    private async Task GenerateAuthTokensAsync(CookieOptionsParameters cookieOptions, HttpContext context,
+        RequestContextInfo requestContext, string userId, CancellationToken cancellation = default)
     {
         var refreshToken = GenerateRefreshToken();
         var (token, expireIn) = GenerateAccessToken(userId);
@@ -92,7 +108,7 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
             AccessToken = token
         };
 
-        await SetAuthTokenDataToCache(authToken, cancellation);
+        await StoreAuthTokenInCache(authToken, cancellation);
         cookieOptions.SetCookie(context, CookieNames.AccessToken, authToken.AccessToken, expireIn);
         cookieOptions.SetCookie(context, CookieNames.RefreshToken, authToken.RefreshToken, DateTime.UtcNow.Add(Lifetime));
 
@@ -102,7 +118,8 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
             authToken.Fingerprint);
     }
 
-    public async Task<TwoFactorAuthenticator> LoginOAuthAsync(CookieOptionsParameters cookieOptions, HttpContext context, User user, CancellationToken cancellation = default)
+    public async Task<TwoFactorAuthenticator> LoginOAuthAsync(CookieOptionsParameters cookieOptions, HttpContext context, User user,
+        CancellationToken cancellation = default)
     {
         var requestContext = new RequestContextInfo(context, cookieOptions);
 
@@ -112,12 +129,13 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
             return TwoFactorAuthenticator.None;
         }
 
-        await CreateFirstAuthTokenToCache(user, requestContext, cancellation);
+        await StoreFirstAuthTokenInCache(user, requestContext, cancellation);
 
         return user.TwoFactorAuthenticator;
     }
 
-    public async Task<bool> LoginAsync(CookieOptionsParameters cookieOptions, HttpContext context, TwoFactorAuthenticator authenticator, string code, CancellationToken cancellation = default)
+    public async Task<bool> LoginAsync(CookieOptionsParameters cookieOptions, HttpContext context, TwoFactorAuthenticator authenticator, string code,
+        CancellationToken cancellation = default)
     {
         var requestContext = new RequestContextInfo(context, cookieOptions);
 
@@ -131,12 +149,23 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
             case TwoFactorAuthenticator.Totp:
                 {
                     if (string.IsNullOrEmpty(firstTokenAuth.Secret))
+                    {
+                        logger.LogWarning("The user {Fingerprint} for {UserId} tried to pass the 2FA even though the secret is empty",
+                            requestContext.Fingerprint,
+                            firstTokenAuth.UserId);
+
                         throw new InvalidOperationException("Required authentication data is missing.");
+                    }
 
                     var totp = new TotpService(firstTokenAuth.Secret);
 
                     if (!totp.VerifyToken(code))
+                    {
+                        await RecordFailedLoginAttempt(requestContext.Fingerprint, firstTokenAuth.UserId, cancellation);
                         throw new SecurityException("Invalid verification code. Please try again.");
+                    }
+
+                    await ResetFailedLoginAttempts(requestContext.Fingerprint, cancellation);
                 }
                 break;
             default:
@@ -147,10 +176,11 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
         return true;
     }
 
-    public async Task<TwoFactorAuthenticator> LoginAsync(CookieOptionsParameters cookieOptions, User user, HttpContext context, string password, string username, CancellationToken cancellation = default)
+    public async Task<TwoFactorAuthenticator> LoginAsync(CookieOptionsParameters cookieOptions, User user, HttpContext context, string password,
+        string username, CancellationToken cancellation = default)
     {
         var requestContext = new RequestContextInfo(context, cookieOptions);
-
+        username = username.Trim();
         await VerifyUserOrThrowError(requestContext, user, password, username, cancellation);
 
         if (user.TwoFactorAuthenticator == TwoFactorAuthenticator.None)
@@ -159,16 +189,17 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
             return TwoFactorAuthenticator.None;
         }
 
-        await CreateFirstAuthTokenToCache(user, requestContext, cancellation);
+        await StoreFirstAuthTokenInCache(user, requestContext, cancellation);
 
         return user.TwoFactorAuthenticator;
     }
 
     public async Task RefreshTokenAsync(CookieOptionsParameters cookieOptions, HttpContext context, CancellationToken cancellation = default)
     {
+        const string defaultMessageError = "The session time has expired";
         var requestContext = new RequestContextInfo(context, cookieOptions);
-        var authToken = await cache.GetAsync<AuthToken>(GetAuthCacheKey(requestContext.Fingerprint), cancellation)
-                        ?? throw new SecurityException("The session time has expired");
+        var authToken = await cache.GetAsync<AuthToken>(GetAuthCacheKey(requestContext.Fingerprint), cancellation) ??
+                        throw new SecurityException(defaultMessageError);
 
         if (authToken.RefreshToken != requestContext.RefreshToken ||
             authToken.UserAgent != requestContext.UserAgent &&
@@ -179,14 +210,52 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
             cookieOptions.DropCookie(context, CookieNames.AccessToken);
             cookieOptions.DropCookie(context, CookieNames.RefreshToken);
 
-            logger.LogWarning("Token validation failed for user ID {UserId}. Fingerprint: {Fingerprint}. Reason: {Reason}.",
-                authToken.UserId,
-                authToken.Fingerprint,
-                authToken.RefreshToken != requestContext.RefreshToken ?
-                    $"Cached refresh token '{authToken.RefreshToken}' does not match the provided refresh token '{requestContext.RefreshToken}'" :
-                    $"User-Agent '{authToken.UserAgent}' and IP '{authToken.Ip}' in cache do not match the provided User-Agent '{requestContext.UserAgent}' and IP '{requestContext.Ip}'");
+            const string error = "Token validation failed for user ID {UserId}. Fingerprint: {Fingerprint}. ";
+            if (authToken.RefreshToken != requestContext.RefreshToken)
+                logger.LogWarning(
+                    error +
+                    "Cached refresh token {ExpectedRefreshToken} does not match the provided refresh token {RefreshToken}",
+                    authToken.UserId,
+                    authToken.Fingerprint,
+                    authToken.RefreshToken,
+                    requestContext.RefreshToken);
+            else
+                logger.LogWarning(
+                    error +
+                    "User-Agent {ExpectedUserAgent} and IP {ExpectedUserIp} in cache do not match the provided " +
+                    "User-Agent {ProvidedUserAgent} and IP {ProvidedIp}",
+                    authToken.UserId,
+                    authToken.Fingerprint,
+                    authToken.UserAgent,
+                    authToken.Ip,
+                    requestContext.UserAgent,
+                    requestContext.Ip);
 
-            throw new SecurityException("The session time has expired");
+            throw new SecurityException(defaultMessageError);
+        }
+
+        if (authToken.UserAgent != requestContext.UserAgent)
+        {
+            logger.LogInformation("The resulting User-Agent {ProvidedUserAgent} does not match the cached " +
+                                  "{ExpectedUserAgent} of the user {UserId} with the fingerprint {Fingerprint}.",
+                requestContext.UserAgent,
+                authToken.UserAgent,
+                authToken.UserId,
+                requestContext.Fingerprint);
+
+            authToken.UserAgent = requestContext.UserAgent;
+        }
+
+        if (authToken.Ip != requestContext.Ip)
+        {
+            logger.LogInformation("The resulting Ip {ProvidedIp} does not match the cached " +
+                                  "{ExpectedIp} of the user {UserId} with the fingerprint {Fingerprint}.",
+                requestContext.Ip,
+                authToken.Ip,
+                authToken.UserId,
+                requestContext.Fingerprint);
+
+            authToken.Ip = requestContext.Ip;
         }
 
         var (token, expireIn) = GenerateAccessToken(authToken.UserId);
@@ -197,7 +266,7 @@ public class AuthService(ICacheService cache, IAccessToken accessTokenService, I
         authToken.AccessToken = token;
         authToken.RefreshToken = newRefreshToken;
 
-        await SetAuthTokenDataToCache(authToken, cancellation);
+        await StoreAuthTokenInCache(authToken, cancellation);
         cookieOptions.SetCookie(context, CookieNames.AccessToken, authToken.AccessToken, expireIn);
         cookieOptions.SetCookie(context, CookieNames.RefreshToken, authToken.RefreshToken, DateTime.UtcNow.Add(Lifetime));
     }

Security/Services/GeneratorKey.cs

@@ -12,7 +12,7 @@ public static class GeneratorKey
         var random = new Random();
         const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
 
-        string charsForGenerate = excludes?
+        var charsForGenerate = excludes?
             .Aggregate(chars, (current, ex) => current.Replace(ex.ToString(), string.Empty)) ?? chars;
 
         if (!string.IsNullOrEmpty(includes))

Security/Services/OAuthService.cs

@@ -6,10 +6,10 @@ using Mirea.Api.Security.Common.Domain.OAuth2.UserInfo;
 using Mirea.Api.Security.Common.Interfaces;
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Net.Http;
 using System.Net.Http.Headers;
-using System.Security;
 using System.Security.Cryptography;
 using System.Text;
 using System.Text.Json;
@@ -18,8 +18,11 @@ using System.Threading.Tasks;
 
 namespace Mirea.Api.Security.Services;
 
-public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider, (string ClientId, string Secret)> providers, string secretKey)
+public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider, (string ClientId, string Secret)> providers,
+    ICacheService cache)
 {
+    public required ReadOnlyMemory<byte> SecretKey { private get; init; }
+
     private static readonly Dictionary<OAuthProvider, OAuthProviderUrisData> ProviderData = new()
     {
         [OAuthProvider.Google] = new OAuthProviderUrisData
@@ -51,7 +54,8 @@ public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider
         }
     };
 
-    private static async Task<OAuthTokenResponse?> ExchangeCodeForTokensAsync(string requestUri, string redirectUrl, string code, string clientId, string secret, CancellationToken cancellation)
+    private static async Task<OAuthTokenResponse?> ExchangeCodeForTokensAsync(string requestUri, string redirectUrl, string code,
+        string clientId, string secret, CancellationToken cancellation)
     {
         var tokenRequest = new HttpRequestMessage(HttpMethod.Post, requestUri)
         {
@@ -77,7 +81,8 @@ public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider
         return JsonSerializer.Deserialize<OAuthTokenResponse>(data);
     }
 
-    private static async Task<OAuthUser?> GetUserProfileAsync(string requestUri, string authHeader, string accessToken, OAuthProvider provider, CancellationToken cancellation)
+    private static async Task<OAuthUser?> GetUserProfileAsync(string requestUri, string authHeader, string accessToken, OAuthProvider provider,
+        CancellationToken cancellation)
     {
         var request = new HttpRequestMessage(HttpMethod.Get, requestUri);
 
@@ -99,30 +104,90 @@ public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider
         return userInfo?.MapToInternalUser();
     }
 
-    private static string GetHmacString(RequestContextInfo contextInfo, string secretKey)
+    private string GetHmacString(RequestContextInfo contextInfo)
     {
-        var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(secretKey));
+        var hmac = new HMACSHA256(SecretKey.ToArray());
         return Convert.ToBase64String(hmac.ComputeHash(
             Encoding.UTF8.GetBytes($"{contextInfo.Fingerprint}_{contextInfo.Ip}_{contextInfo.UserAgent}")));
     }
 
-    public Uri GetProviderRedirect(HttpContext context, CookieOptionsParameters cookieOptions, string redirectUri, OAuthProvider provider)
+    private string EncryptPayload(OAuthPayload payload)
+    {
+        var data = JsonSerializer.Serialize(payload);
+
+        var aes = Aes.Create();
+        aes.Key = SecretKey.ToArray();
+        aes.GenerateIV();
+
+        using var encryptor = aes.CreateEncryptor(aes.Key, aes.IV);
+        using var ms = new MemoryStream();
+
+        ms.Write(aes.IV, 0, aes.IV.Length);
+
+        using (var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
+        using (var writer = new StreamWriter(cs))
+        {
+            writer.Write(data);
+        }
+
+        return Convert.ToBase64String(ms.ToArray());
+    }
+
+    private OAuthPayload DecryptPayload(string encryptedData)
+    {
+        try
+        {
+            var cipherBytes = Convert.FromBase64String(encryptedData);
+
+            using var aes = Aes.Create();
+            aes.Key = SecretKey.ToArray();
+
+            var iv = new byte[16];
+            Array.Copy(cipherBytes, 0, iv, 0, iv.Length);
+            aes.IV = iv;
+
+            using var ms = new MemoryStream(cipherBytes, 16, cipherBytes.Length - 16);
+            using var decryptor = aes.CreateDecryptor(aes.Key, aes.IV);
+
+            using var cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read);
+            using var reader = new StreamReader(cs);
+
+            var data = reader.ReadToEnd();
+
+            return JsonSerializer.Deserialize<OAuthPayload>(data) ??
+                   throw new NullReferenceException($"Couldn't convert data to {nameof(OAuthPayload)}.");
+        }
+        catch (Exception ex)
+        {
+            logger.LogWarning(ex, "Couldn't decrypt the data OAuth request.");
+            throw new InvalidOperationException("Couldn't decrypt the data.", ex);
+        }
+    }
+
+    public Uri GetProviderRedirect(HttpContext context, CookieOptionsParameters cookieOptions, string redirectUri,
+        OAuthProvider provider, Uri callback)
     {
         var (clientId, _) = providers[provider];
 
         var requestInfo = new RequestContextInfo(context, cookieOptions);
-        var state = GetHmacString(requestInfo, secretKey);
+        var payload = EncryptPayload(new OAuthPayload()
+        {
+            Provider = provider,
+            Callback = callback.AbsoluteUri
+        });
+
+        var checksum = GetHmacString(requestInfo);
 
         var redirectUrl = $"?client_id={clientId}" +
                                 "&response_type=code" +
                                 $"&redirect_uri={redirectUri}" +
                                 $"&scope={ProviderData[provider].Scope}" +
-                                $"&state={Uri.EscapeDataString(state + "_" + Enum.GetName(provider))}";
+                                $"&state={Uri.EscapeDataString(payload + "_" + checksum)}";
 
         logger.LogInformation("Redirecting user Fingerprint: {Fingerprint} to OAuth provider {Provider} with state: {State}",
             requestInfo.Fingerprint,
             provider,
-            state);
+            checksum);
 
         return new Uri(ProviderData[provider].RedirectUrl + redirectUrl);
     }
@@ -130,59 +195,98 @@ public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider
     public (OAuthProvider Provider, Uri Redirect)[] GetAvailableProviders(string redirectUri) =>
         [.. providers.Select(x => (x.Key, new Uri(redirectUri.TrimEnd('/') + "/?provider=" + (int)x.Key)))];
 
-    public async Task<(OAuthProvider provider, OAuthUser User)> LoginOAuth(HttpContext context, CookieOptionsParameters cookieOptions, string redirectUrl, string code, string state, CancellationToken cancellation = default)
+    public async Task<LoginOAuthResult> LoginOAuth(HttpContext context, CookieOptionsParameters cookieOptions,
+        string redirectUrl, string code, string state, CancellationToken cancellation = default)
     {
-        var partsState = state.Split('_');
-
-        if (!Enum.TryParse<OAuthProvider>(partsState.Last(), true, out var provider) ||
-            !providers.TryGetValue(provider, out var providerInfo) ||
-            !ProviderData.TryGetValue(provider, out var currentProviderStruct))
+        var result = new LoginOAuthResult()
         {
-            logger.LogWarning("Failed to parse OAuth provider from state: {State}", state);
-            throw new InvalidOperationException("Invalid authorization request.");
+            Token = GeneratorKey.GenerateBase64(32)
+        };
+        var parts = state.Split('_');
+
+        if (parts.Length != 2)
+        {
+            result.ErrorMessage = "The request data is invalid or malformed.";
+            return result;
         }
 
-        var secretStateData = string.Join("_", partsState.SkipLast(1));
-        var requestInfo = new RequestContextInfo(context, cookieOptions);
-        var secretData = GetHmacString(requestInfo, secretKey);
+        var payload = DecryptPayload(parts[0]);
+        var checksum = parts[1];
 
-        if (secretData != secretStateData)
+        result.Callback = new Uri(payload.Callback);
+
+        if (!providers.TryGetValue(payload.Provider, out var providerInfo) ||
+            !ProviderData.TryGetValue(payload.Provider, out var currentProviderStruct))
+        {
+            logger.LogWarning("The OAuth provider specified in the payload " +
+                              "is not registered as a possible data recipient from state: {State}",
+                state);
+
+            result.ErrorMessage = "Invalid authorization request. Please try again later.";
+            return result;
+        }
+
+        var requestInfo = new RequestContextInfo(context, cookieOptions);
+        var checksumRequest = GetHmacString(requestInfo);
+
+        result.ErrorMessage = "Authorization failed. Please try again later.";
+
+        if (checksumRequest != checksum)
         {
             logger.LogWarning(
                 "Fingerprint mismatch. Possible CSRF attack detected. Fingerprint: {Fingerprint}, State: {State}, ExpectedState: {ExpectedState}",
                 requestInfo.Fingerprint,
-                secretData,
-                secretStateData
+                checksumRequest,
+                checksum
             );
-            throw new SecurityException("Suspicious activity detected. Please try again.");
+
+            return result;
         }
 
-        OAuthTokenResponse? accessToken = null;
+        OAuthTokenResponse? accessToken;
         try
         {
-            accessToken = await ExchangeCodeForTokensAsync(currentProviderStruct.TokenUrl, redirectUrl, code, providerInfo.ClientId, providerInfo.Secret, cancellation);
+            accessToken = await ExchangeCodeForTokensAsync(currentProviderStruct.TokenUrl, redirectUrl, code, providerInfo.ClientId,
+                providerInfo.Secret, cancellation);
         }
         catch (Exception ex)
         {
-            logger.LogWarning(ex, "Failed to exchange code for access token with provider {Provider}. State: {State}", provider, state);
+            logger.LogWarning(ex, "Failed to exchange code for access token with provider {Provider}. State: {State}",
+                payload.Provider,
+                checksum);
+
+            return result;
         }
 
         if (accessToken == null)
-            throw new SecurityException("Unable to complete authorization with the provider. Please try again later.");
+            return result;
 
-        OAuthUser? result = null;
+        OAuthUser? user;
         try
         {
-            result = await GetUserProfileAsync(currentProviderStruct.UserInfoUrl, currentProviderStruct.AuthHeader, accessToken.AccessToken, provider, cancellation);
+            user = await GetUserProfileAsync(currentProviderStruct.UserInfoUrl, currentProviderStruct.AuthHeader, accessToken.AccessToken,
+                payload.Provider, cancellation);
         }
         catch (Exception ex)
         {
-            logger.LogWarning(ex, "Failed to retrieve user information from provider {Provider}", provider);
+            logger.LogWarning(ex, "Failed to retrieve user information from provider {Provider}",
+                payload.Provider);
+
+            return result;
         }
 
-        if (result == null)
-            throw new SecurityException("Unable to retrieve user information. Please check the details and try again.");
+        if (user == null)
+            return result;
 
-        return (provider, result);
+        result.ErrorMessage = null;
+        result.Success = true;
+
+        await cache.SetAsync(
+            result.Token,
+            JsonSerializer.SerializeToUtf8Bytes(user),
+            absoluteExpirationRelativeToNow: TimeSpan.FromMinutes(15),
+            cancellationToken: cancellation);
+
+        return result;
     }
 }

Security/Services/PasswordHashService.cs

@@ -34,8 +34,8 @@ public class PasswordHashService
         if (a.Length != b.Length)
             return false;
 
-        int result = 0;
-        for (int i = 0; i < a.Length; i++)
+        var result = 0;
+        for (var i = 0; i < a.Length; i++)
             result |= a[i] ^ b[i];
         return result == 0;
     }

SqlData/Application/Cqrs/Campus/Queries/GetCampusBasicInfoList/CampusBasicInfoVm.cs

@@ -10,5 +10,5 @@ public class CampusBasicInfoVm
     /// <summary>
     /// The list of campus basic information.
     /// </summary>
-    public IList<CampusBasicInfoDto> Campuses { get; set; } = new List<CampusBasicInfoDto>();
+    public IEnumerable<CampusBasicInfoDto> Campuses { get; set; } = [];
 }

SqlData/Application/Cqrs/Campus/Queries/GetCampusDetails/GetCampusDetailsQueryHandler.cs

@@ -11,7 +11,8 @@ public class GetCampusDetailsQueryHandler(ICampusDbContext dbContext) : IRequest
 {
     public async Task<CampusDetailsVm> Handle(GetCampusDetailsQuery request, CancellationToken cancellationToken)
     {
-        var campus = await dbContext.Campuses.FirstOrDefaultAsync(c => c.Id == request.Id, cancellationToken) ?? throw new NotFoundException(typeof(Domain.Schedule.Campus), request.Id);
+        var campus = await dbContext.Campuses.FirstOrDefaultAsync(c => c.Id == request.Id, cancellationToken) ??
+                     throw new NotFoundException(typeof(Domain.Schedule.Campus), request.Id);
 
         return new CampusDetailsVm()
         {

SqlData/Application/Cqrs/Discipline/Queries/GetDisciplineDetails/GetDisciplineInfoQueryHandler.cs

@@ -11,7 +11,8 @@ public class GetDisciplineInfoQueryHandler(IDisciplineDbContext dbContext) : IRe
 {
     public async Task<DisciplineInfoVm> Handle(GetDisciplineInfoQuery request, CancellationToken cancellationToken)
     {
-        var discipline = await dbContext.Disciplines.FirstOrDefaultAsync(d => d.Id == request.Id, cancellationToken) ?? throw new NotFoundException(typeof(Domain.Schedule.Discipline), request.Id);
+        var discipline = await dbContext.Disciplines.FirstOrDefaultAsync(d => d.Id == request.Id, cancellationToken) ??
+                         throw new NotFoundException(typeof(Domain.Schedule.Discipline), request.Id);
 
         return new DisciplineInfoVm()
         {

SqlData/Application/Cqrs/Discipline/Queries/GetDisciplineList/DisciplineListVm.cs

@@ -10,5 +10,5 @@ public class DisciplineListVm
     /// <summary>
     /// The list of disciplines.
     /// </summary>
-    public IList<DisciplineLookupDto> Disciplines { get; set; } = new List<DisciplineLookupDto>();
+    public IEnumerable<DisciplineLookupDto> Disciplines { get; set; } = [];
 }

SqlData/Application/Cqrs/Faculty/Queries/GetFacultyList/FacultyListVm.cs

@@ -10,5 +10,5 @@ public class FacultyListVm
     /// <summary>
     /// The list of faculties.
     /// </summary>
-    public IList<FacultyLookupDto> Faculties { get; set; } = new List<FacultyLookupDto>();
+    public IEnumerable<FacultyLookupDto> Faculties { get; set; } = [];
 }

SqlData/Application/Cqrs/Faculty/Queries/GetFacultyList/FacultyLookupDto.cs

@@ -14,9 +14,4 @@ public class FacultyLookupDto
     /// The name of the faculty.
     /// </summary>
     public required string Name { get; set; }
-
-    /// <summary>
-    /// ID indicating the faculty's affiliation to the campus.
-    /// </summary>
-    public int? CampusId { get; set; }
 }

SqlData/Application/Cqrs/Group/Queries/GetGroupList/GroupListVm.cs

@@ -10,5 +10,5 @@ public class GroupListVm
     /// <summary>
     /// The list of groups.
     /// </summary>
-    public IList<GroupLookupDto> Groups { get; set; } = new List<GroupLookupDto>();
+    public IEnumerable<GroupLookupDto> Groups { get; set; } = [];
 }

SqlData/Application/Cqrs/LectureHall/Queries/GetLectureHallList/LectureHallListVm.cs

@@ -10,5 +10,5 @@ public class LectureHallListVm
     /// <summary>
     /// The list of lecture hall.
     /// </summary>
-    public IList<LectureHallLookupDto> LectureHalls { get; set; } = new List<LectureHallLookupDto>();
+    public IEnumerable<LectureHallLookupDto> LectureHalls { get; set; } = [];
 }

SqlData/Application/Cqrs/Professor/Queries/GetProfessorDetails/GetProfessorInfoQueryHandler.cs

@@ -11,7 +11,8 @@ public class GetProfessorInfoQueryHandler(IProfessorDbContext dbContext) : IRequ
 {
     public async Task<ProfessorInfoVm> Handle(GetProfessorInfoQuery request, CancellationToken cancellationToken)
     {
-        var professor = await dbContext.Professors.FirstOrDefaultAsync(p => p.Id == request.Id, cancellationToken) ?? throw new NotFoundException(typeof(Domain.Schedule.Professor), request.Id);
+        var professor = await dbContext.Professors.FirstOrDefaultAsync(p => p.Id == request.Id, cancellationToken) ??
+                        throw new NotFoundException(typeof(Domain.Schedule.Professor), request.Id);
 
         return new ProfessorInfoVm()
         {

SqlData/Application/Cqrs/Professor/Queries/GetProfessorDetailsBySearch/GetProfessorInfoSearchQueryHandler.cs

@@ -27,7 +27,7 @@ public class GetProfessorInfoSearchQueryHandler(IProfessorDbContext dbContext) :
                 Id = x.Id,
                 Name = x.Name,
                 AltName = x.AltName
-            }).ToList()
+            })
         };
     }
 }

SqlData/Application/Cqrs/Professor/Queries/GetProfessorDetailsBySearch/ProfessorInfoListVm.cs

@@ -11,5 +11,5 @@ public class ProfessorInfoListVm
     /// <summary>
     /// List of <see cref="ProfessorInfoVm"/>
     /// </summary>
-    public required IList<ProfessorInfoVm> Details { get; set; }
+    public IEnumerable<ProfessorInfoVm> Details { get; set; } = [];
 }

SqlData/Application/Cqrs/Professor/Queries/GetProfessorList/ProfessorListVm.cs

@@ -10,5 +10,5 @@ public class ProfessorListVm
     /// <summary>
     /// The list of professors.
     /// </summary>
-    public IList<ProfessorLookupDto> Professors { get; set; } = new List<ProfessorLookupDto>();
+    public IEnumerable<ProfessorLookupDto> Professors { get; set; } = [];
 }

SqlData/Application/Cqrs/Schedule/Queries/GetScheduleList/GetScheduleListQueryHandler.cs

@@ -83,7 +83,7 @@ public class GetScheduleListQueryHandler(ILessonDbContext dbContext) : IRequestH
                 .Select(la => la.ProfessorId),
 
             LinkToMeet = l.LessonAssociations!.Select(la => la.LinkToMeet)
-        }).ToList();
+        });
 
         return new ScheduleListVm
         {

SqlData/Application/Cqrs/Schedule/Queries/GetScheduleList/ScheduleListVm.cs

@@ -10,5 +10,5 @@ public class ScheduleListVm
     /// <summary>
     /// Gets or sets the list of schedules.
     /// </summary>
-    public IList<ScheduleLookupDto> Schedules { get; set; } = new List<ScheduleLookupDto>();
+    public IEnumerable<ScheduleLookupDto> Schedules { get; set; } = [];
 }

SqlData/Application/DependencyInjection.cs

@@ -1,4 +1,4 @@
-using FluentValidation;
+using FluentValidation;
 using MediatR;
 using Microsoft.Extensions.DependencyInjection;
 using Mirea.Api.DataAccess.Application.Common.Behaviors;
@@ -11,7 +11,7 @@ public static class DependencyInjection
     public static IServiceCollection AddApplication(this IServiceCollection services)
     {
         services.AddMediatR(cfg => cfg.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly()));
-        services.AddValidatorsFromAssemblies(new[] { Assembly.GetExecutingAssembly() });
+        services.AddValidatorsFromAssemblies([Assembly.GetExecutingAssembly()]);
         services.AddTransient(typeof(IPipelineBehavior<,>),
             typeof(ValidationBehavior<,>));
         return services;

SqlData/Persistence/Common/ModelBuilderExtensions.cs

@@ -9,7 +9,7 @@ public static class ModelBuilderExtensions
     {
         var applyGenericMethod = typeof(ModelBuilder)
             .GetMethods()
-            .First(m => m.Name == "ApplyConfiguration" &&
+            .First(m => m.Name == nameof(ApplyConfiguration) &&
                         m.GetParameters().Any(p => p.ParameterType.GetGenericTypeDefinition() == typeof(IEntityTypeConfiguration<>)));
 
         var entityType = configuration.GetType().GetInterfaces()

SqlData/Persistence/DbInitializer.cs

@@ -4,8 +4,6 @@ namespace Mirea.Api.DataAccess.Persistence;
 
 public static class DbInitializer
 {
-    public static void Initialize(DbContext dbContext)
-    {
+    public static void Initialize(DbContext dbContext) =>
         dbContext.Database.Migrate();
-    }
 }