implement account lockout after 3 failed login attempts with 5-minute cooldown period

backend/internal/auth/errors.go

@@ -1,6 +1,9 @@
 package auth
 
-import "errors"
+import (
+	"errors"
+	"time"
+)
 
 var (
 	ErrInvalidCredentials = errors.New("invalid credentials")
@@ -10,3 +13,11 @@ var (
 	ErrCredentialsEmpty   = errors.New("username and password cannot be empty")
 	ErrPasswordTooShort   = errors.New("password must be at least 6 characters long")
 )
+
+type AccountLockedError struct {
+	LockedUntil time.Time
+}
+
+func (e AccountLockedError) Error() string {
+	return "account temporarily locked"
+}

backend/internal/auth/handler.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	"errors"
 	"net/http"
 
 	"github.com/gin-gonic/gin"
@@ -35,6 +36,16 @@ func (h *Handler) Login(c *gin.Context) {
 
 	token, err := h.authService.Login(c.Request.Context(), req.Username, req.Password)
 	if err != nil {
+		var lockErr AccountLockedError
+		if errors.As(err, &lockErr) {
+			c.JSON(http.StatusTooManyRequests, gin.H{
+				"error":        "Слишком много неверных попыток. Попробуйте через 5 минут",
+				"code":         "account_temporarily_locked",
+				"locked_until": lockErr.LockedUntil.Format("2006-01-02T15:04:05Z07:00"),
+			})
+			return
+		}
+
 		switch err {
 		case ErrUserNotFound, ErrInvalidCredentials:
 			c.JSON(http.StatusUnauthorized, gin.H{"error": "invalid credentials"})

backend/internal/auth/service.go

@@ -71,10 +71,33 @@ func (s *Service) Login(ctx context.Context, username, password string) (string,
 		return "", err
 	}
 
+	now := time.Now()
+	if user.LockedUntil.Valid {
+		if user.LockedUntil.Time.After(now) {
+			return "", AccountLockedError{LockedUntil: user.LockedUntil.Time}
+		}
+		if err := s.queries.ResetLoginFailures(ctx, username); err != nil {
+			return "", err
+		}
+	}
+
 	if !s.VerifyPassword(user.PasswordHash, password) {
+		failedLogin, err := s.queries.RecordFailedLogin(ctx, username)
+		if err != nil {
+			return "", err
+		}
+		if failedLogin.LockedUntil.Valid && failedLogin.LockedUntil.Time.After(now) {
+			return "", AccountLockedError{LockedUntil: failedLogin.LockedUntil.Time}
+		}
 		return "", ErrInvalidCredentials
 	}
 
+	if user.FailedLoginAttempts > 0 || user.LockedUntil.Valid {
+		if err := s.queries.ResetLoginFailures(ctx, username); err != nil {
+			return "", err
+		}
+	}
+
 	token, err := GenerateToken(uuid.UUID(user.ID.Bytes), s.secret, s.expiry)
 	if err != nil {
 		return "", err

backend/internal/db/migrations/000004_add_login_lockout_fields.down.sql

@@ -0,0 +1,3 @@
+ALTER TABLE users
+DROP COLUMN locked_until,
+DROP COLUMN failed_login_attempts;

backend/internal/db/migrations/000004_add_login_lockout_fields.up.sql

@@ -0,0 +1,3 @@
+ALTER TABLE users
+ADD COLUMN failed_login_attempts INTEGER NOT NULL DEFAULT 0,
+ADD COLUMN locked_until TIMESTAMPTZ;

backend/internal/db/queries/query.sql

@@ -6,6 +6,25 @@ RETURNING *;
 -- name: GetUserByUsername :one
 SELECT * FROM users WHERE username = $1;
 
+-- name: ResetLoginFailures :exec
+UPDATE users
+SET failed_login_attempts = 0,
+    locked_until = NULL
+WHERE username = $1;
+
+-- name: RecordFailedLogin :one
+UPDATE users
+SET failed_login_attempts = CASE
+        WHEN failed_login_attempts + 1 >= 3 THEN 3
+        ELSE failed_login_attempts + 1
+    END,
+    locked_until = CASE
+        WHEN failed_login_attempts + 1 >= 3 THEN NOW() + INTERVAL '5 minutes'
+        ELSE locked_until
+    END
+WHERE username = $1
+RETURNING failed_login_attempts, locked_until;
+
 -- name: GetDeliveriesByDate :many
 SELECT * FROM deliveries WHERE date = $1;
  

backend/internal/db/sqlc/models.go

@@ -33,8 +33,10 @@ type Delivery struct {
 }
 
 type User struct {
-	ID           pgtype.UUID      `db:"id" json:"id"`
-	Username     string           `db:"username" json:"username"`
-	PasswordHash string           `db:"password_hash" json:"password_hash"`
-	CreatedAt    pgtype.Timestamp `db:"created_at" json:"created_at"`
+	ID                  pgtype.UUID        `db:"id" json:"id"`
+	Username            string             `db:"username" json:"username"`
+	PasswordHash        string             `db:"password_hash" json:"password_hash"`
+	CreatedAt           pgtype.Timestamp   `db:"created_at" json:"created_at"`
+	FailedLoginAttempts int32              `db:"failed_login_attempts" json:"failed_login_attempts"`
+	LockedUntil         pgtype.Timestamptz `db:"locked_until" json:"locked_until"`
 }

backend/internal/db/sqlc/querier.go

@@ -18,6 +18,8 @@ type Querier interface {
 	GetDeliveryByID(ctx context.Context, id pgtype.UUID) (Delivery, error)
 	GetDeliveryCount(ctx context.Context) ([]GetDeliveryCountRow, error)
 	GetUserByUsername(ctx context.Context, username string) (User, error)
+	RecordFailedLogin(ctx context.Context, username string) (RecordFailedLoginRow, error)
+	ResetLoginFailures(ctx context.Context, username string) error
 	UpdateDelivery(ctx context.Context, arg UpdateDeliveryParams) error
 	UpdateDeliveryStatus(ctx context.Context, arg UpdateDeliveryStatusParams) error
 }

backend/internal/db/sqlc/query.sql.go

@@ -91,7 +91,7 @@ func (q *Queries) CreateDelivery(ctx context.Context, arg CreateDeliveryParams)
 const createUser = `-- name: CreateUser :one
 INSERT INTO users (username, password_hash)
 VALUES ($1, $2)
-RETURNING id, username, password_hash, created_at
+RETURNING id, username, password_hash, created_at, failed_login_attempts, locked_until
 `
 
 type CreateUserParams struct {
@@ -107,6 +107,8 @@ func (q *Queries) CreateUser(ctx context.Context, arg CreateUserParams) (User, e
 		&i.Username,
 		&i.PasswordHash,
 		&i.CreatedAt,
+		&i.FailedLoginAttempts,
+		&i.LockedUntil,
 	)
 	return i, err
 }
@@ -231,7 +233,7 @@ func (q *Queries) GetDeliveryCount(ctx context.Context) ([]GetDeliveryCountRow,
 }
 
 const getUserByUsername = `-- name: GetUserByUsername :one
-SELECT id, username, password_hash, created_at FROM users WHERE username = $1
+SELECT id, username, password_hash, created_at, failed_login_attempts, locked_until FROM users WHERE username = $1
 `
 
 func (q *Queries) GetUserByUsername(ctx context.Context, username string) (User, error) {
@@ -242,10 +244,50 @@ func (q *Queries) GetUserByUsername(ctx context.Context, username string) (User,
 		&i.Username,
 		&i.PasswordHash,
 		&i.CreatedAt,
+		&i.FailedLoginAttempts,
+		&i.LockedUntil,
 	)
 	return i, err
 }
 
+const recordFailedLogin = `-- name: RecordFailedLogin :one
+UPDATE users
+SET failed_login_attempts = CASE
+        WHEN failed_login_attempts + 1 >= 3 THEN 3
+        ELSE failed_login_attempts + 1
+    END,
+    locked_until = CASE
+        WHEN failed_login_attempts + 1 >= 3 THEN NOW() + INTERVAL '5 minutes'
+        ELSE locked_until
+    END
+WHERE username = $1
+RETURNING failed_login_attempts, locked_until
+`
+
+type RecordFailedLoginRow struct {
+	FailedLoginAttempts int32              `db:"failed_login_attempts" json:"failed_login_attempts"`
+	LockedUntil         pgtype.Timestamptz `db:"locked_until" json:"locked_until"`
+}
+
+func (q *Queries) RecordFailedLogin(ctx context.Context, username string) (RecordFailedLoginRow, error) {
+	row := q.db.QueryRow(ctx, recordFailedLogin, username)
+	var i RecordFailedLoginRow
+	err := row.Scan(&i.FailedLoginAttempts, &i.LockedUntil)
+	return i, err
+}
+
+const resetLoginFailures = `-- name: ResetLoginFailures :exec
+UPDATE users
+SET failed_login_attempts = 0,
+    locked_until = NULL
+WHERE username = $1
+`
+
+func (q *Queries) ResetLoginFailures(ctx context.Context, username string) error {
+	_, err := q.db.Exec(ctx, resetLoginFailures, username)
+	return err
+}
+
 const updateDelivery = `-- name: UpdateDelivery :exec
 UPDATE deliveries SET
     date = $1,

frontend/src/api/client.ts

@@ -76,16 +76,16 @@ async function fetchApi<T>(
       });
 
       if (!response.ok) {
+        const errorData = await response.json().catch(() => null);
         // Handle 401 unauthorized
-        if (response.status === 401) {
+        if (response.status === 401 && endpoint !== '/api/auth/login') {
           handleUnauthorized();
           throw new ApiError('Unauthorized', 401);
         }
-        const errorData = await response.json().catch(() => null);
         throw new ApiError(
           errorData?.error || `HTTP ${response.status}`,
           response.status,
-          errorData?.details
+          errorData
         );
       }
 

frontend/src/stores/authStore.ts

@@ -1,5 +1,6 @@
 import { create } from 'zustand';
 import { authApi } from '../api/auth';
+import { ApiError } from '../api/client';
 import { useToastStore } from './toastStore';
 import type { User, LoginRequest } from '../types';
 
@@ -16,6 +17,28 @@ interface AuthState {
 
 const TOKEN_KEY = 'auth_token';
 const USER_KEY = 'auth_user';
+const LOCKED_ACCOUNT_CODE = 'account_temporarily_locked';
+
+function getLoginErrorMessage(error: unknown): string {
+  if (error instanceof ApiError) {
+    const details = error.details as { code?: string; locked_until?: string } | null;
+
+    if (error.status === 429 && details?.code === LOCKED_ACCOUNT_CODE) {
+      if (details.locked_until) {
+        const lockedUntil = new Date(details.locked_until);
+        const secondsLeft = Math.ceil((lockedUntil.getTime() - Date.now()) / 1000);
+        if (Number.isFinite(secondsLeft) && secondsLeft > 0) {
+          const minutesLeft = Math.ceil(secondsLeft / 60);
+          return `Слишком много неверных попыток. Попробуйте через ${minutesLeft} мин.`;
+        }
+      }
+
+      return 'Слишком много неверных попыток. Попробуйте через 5 минут';
+    }
+  }
+
+  return error instanceof Error ? error.message : 'Ошибка входа';
+}
 
 export const useAuthStore = create<AuthState>((set) => ({
   token: null,
@@ -45,8 +68,7 @@ export const useAuthStore = create<AuthState>((set) => ({
       useToastStore.getState().addToast('Вход выполнен успешно', 'success');
     } catch (error) {
       set({ isLoading: false });
-      const message = error instanceof Error ? error.message : 'Ошибка входа';
-      useToastStore.getState().addToast(message, 'error');
+      useToastStore.getState().addToast(getLoginErrorMessage(error), 'error');
       throw error;
     }
   },