feat: log LLM metadata to question_cache_meta

Made-with: Cursor
feat: add LLM retry and fallback
2026-03-04 14:37:58 +03:00 · 2026-03-04 14:19:04 +03:00 · 2026-03-04 14:18:23 +03:00 · 2026-03-04 14:18:22 +03:00 · 2026-03-04 14:17:54 +03:00 · 2026-03-04 14:16:23 +03:00
44 changed files with 3815 additions and 1 deletions
--- a/.env.example
+++ b/.env.example
@@ -0,0 +1,45 @@
+# Server
+PORT=3000
+HOST=0.0.0.0
+NODE_ENV=development
+
+# Database
+DATABASE_URL=postgresql://samreshu:samreshu_dev@localhost:5432/samreshu
+
+# Redis
+REDIS_URL=redis://localhost:6379
+
+# Auth
+JWT_SECRET=dev-secret-change-in-production-min-32-chars
+JWT_ACCESS_TTL=15m
+JWT_REFRESH_TTL=7d
+
+# LLM
+LLM_BASE_URL=http://localhost:11434/v1
+LLM_MODEL=qwen2.5:14b
+LLM_API_KEY=
+LLM_TIMEOUT_MS=15000
+LLM_MAX_RETRIES=1
+LLM_TEMPERATURE=0.7
+LLM_MAX_TOKENS=2048
+
+# Rate limits
+RATE_LIMIT_LOGIN=5
+RATE_LIMIT_REGISTER=3
+RATE_LIMIT_FORGOT_PASSWORD=3
+RATE_LIMIT_VERIFY_EMAIL=5
+RATE_LIMIT_API_AUTHED=100
+RATE_LIMIT_API_GUEST=30
+
+# CORS (comma-separated origins)
+CORS_ORIGINS=http://localhost:5173,http://localhost:3000
+
+# Email (dev — mailpit / mailtrap)
+SMTP_HOST=localhost
+SMTP_PORT=1025
+SMTP_USER=
+SMTP_PASS=
+EMAIL_FROM=noreply@samreshu.dev
+
+# Sentry (optional for dev)
+SENTRY_DSN=
--- a/.gitmodules
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "samreshu_docs"]
+	path = samreshu_docs
+	url = https://git.vakanaut.ru/admin/samreshu_docs.git
--- a/AGENT_TASKS.md
+++ b/AGENT_TASKS.md
@@ -0,0 +1,307 @@
+# Распределение задач по агентам (MVP 0)
+
+Документ для параллельной работы нескольких агентов. Каждый агент работает в **отдельной сессии Cursor** (отдельное окно чата). После выполнения **каждой задачи** — отдельный коммит по conventional commits.
+
+## Как запустить агента
+
+1. Открыть **новую сессию чата** (новое окно Composer/Chat в Cursor)
+2. Скопировать промпт для нужного агента из раздела ниже
+3. Агент выполнит свои задачи и сделает коммиты
+4. Повторить для следующего агента
+
+### Промпты для запуска агентов
+
+**Agent A (Infrastructure):**
+
+```text
+Implement Agent A tasks from AGENT_TASKS.md. Work in branch feat/infra-core. 
+Do tasks A1–A9 in order. After EACH task, run: git add -A && git commit -m "<message from table>".
+Use conventional commits. Do not touch schema or auth/tests/profile/llm/admin code.
+```
+
+**Agent B (DB Schema):**
+
+```text
+Implement Agent B tasks from AGENT_TASKS.md. Work in branch feat/db-schema. 
+Do tasks B1–B7. After EACH task, commit with the message from the table.
+Assume Agent A has created plugins. Generate migrations with npm run db:generate.
+```
+
+**Agent C (Auth):**
+
+```text
+Implement Agent C tasks from AGENT_TASKS.md. Work in branch feat/auth. 
+Merge or rebase from dev first. Do tasks C1–C7, commit after each.
+```
+
+**Agent D (Profile):**
+
+```text
+Implement Agent D tasks from AGENT_TASKS.md. Work in branch feat/profile-subscription.
+Merge dev first. Do tasks D1–D5, commit after each.
+```
+
+**Agent E (Tests & Questions):**
+
+```text
+Implement Agent E tasks from AGENT_TASKS.md. Work in branch feat/tests-questions.
+Requires Auth, Profile, LLM done. Do E1–E5, commit after each.
+```
+
+**Agent F (LLM):**
+
+```text
+Implement Agent F tasks from AGENT_TASKS.md. Work in branch feat/llm-service.
+Do F1–F5, commit after each. Export LlmService interface for QuestionService.
+```
+
+**Agent G (Admin):**
+
+```text
+Implement Agent G tasks from AGENT_TASKS.md. Work in branch feat/admin-qa.
+Do G1–G4, commit after each.
+```
+
+**Agent H (Testing):**
+
+```text
+Implement Agent H tasks from AGENT_TASKS.md. Work in branch feat/testing.
+Do H1–H7, commit after each. Target ≥70% coverage on services.
+```
+
+## Текущее состояние репозитория
+
+Часть работы уже выполнена одним агентом:
+
+- **Infra (A):** package.json, config, plugins (database, redis, security, rateLimit), app.ts, server.ts, utils/errors, utils/uuid, docker-compose, .env.example
+- **Schema (B):** все схемы в src/db/schema, drizzle.config, migrate.ts. Миграции ещё не сгенерированы (нужен `npm run db:generate`)
+
+Агентам B–H при старте: проверить, что уже есть, и дописать недостающее. Не дублировать сделанное. Коммитить только свои изменения.
+
+---
+
+## Формат коммитов
+
+Использовать [conventional commits](samreshu_docs/principles/git-workflow.md):
+
+- `feat:` — новый функционал
+- `fix:` — исправление бага
+- `refactor:` — рефакторинг
+- `chore:` — инфраструктура, зависимости, конфиг
+- `test:` — тесты
+
+Примеры: `feat: add auth register endpoint`, `chore: add database plugin`, `test: add auth service unit tests`.
+
+---
+
+## Волны запуска и зависимости
+
+```text
+Волна 1 (старт сразу, параллельно):
+  Agent A ────────────────────────────►
+  Agent B ────────────────────────────►
+
+Волна 2 (после завершения A + B):
+  Agent C ────────────────────────────►
+  Agent D ────────────────────────────►
+  Agent F ────────────────────────────►
+
+Волна 3 (после C, D, F):
+  Agent E ────────────────────────────►
+  Agent G ────────────────────────────►
+  Agent H ────────────────────────────► (может стартовать частично после C)
+```
+
+---
+
+## Agent A: Infrastructure & Core Backend
+
+**Зависимости:** нет (запускать первым)
+
+**Ветка:** `feat/infra-core` (создать от `main`/`dev`)
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| A1 | package.json, tsconfig, .nvmrc, .gitignore | `chore: init project with Fastify and TypeScript` |
+| A2 | src/config/env.ts с Zod-валидацией | `chore: add env config with validation` |
+| A3 | src/plugins/redis.ts | `feat: add Redis plugin` |
+| A4 | src/plugins/database.ts | `feat: add database plugin with Drizzle` |
+| A5 | src/plugins/security.ts (helmet + cors) | `feat: add security plugin` |
+| A6 | src/plugins/rateLimit.ts | `feat: add rate limit plugin with Redis` |
+| A7 | src/utils/errors.ts, src/utils/uuid.ts | `chore: add error utils and uuid7 helper` |
+| A8 | src/app.ts — error handler, логирование | `feat: add Fastify app with error handler` |
+| A9 | src/server.ts, docker-compose.dev.yml, .env.example | `chore: add server entry and dev docker compose` |
+
+**Итого:** 9 коммитов. После завершения — PR в `dev`.
+
+---
+
+## Agent B: Data Model & Drizzle Schema
+
+**Зависимости:** Agent A (нужен database plugin). Может стартовать после A4.
+
+**Ветка:** `feat/db-schema`
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| B1 | src/db/schema/enums.ts | `feat: add Drizzle enums for schema` |
+| B2 | src/db/schema/users.ts, sessions.ts, subscriptions.ts | `feat: add users and auth tables schema` |
+| B3 | src/db/schema/tests.ts, testQuestions.ts | `feat: add tests and test_questions schema` |
+| B4 | src/db/schema/questionBank.ts, questionCacheMeta.ts, questionReports.ts | `feat: add question bank schema` |
+| B5 | src/db/schema/userStats.ts, auditLogs.ts, userQuestionLog.ts, verificationTokens.ts | `feat: add user_stats, audit_logs and verification tokens schema` |
+| B6 | src/db/schema/index.ts, drizzle.config.ts, migrate.ts | `chore: wire schema and migrations` |
+| B7 | Генерация миграций (npm run db:generate), seed скрипт | `chore: add initial migration and seed script` |
+
+**Итого:** 7 коммитов. После завершения — PR в `dev`.
+
+---
+
+## Agent C: Auth & Sessions Service
+
+**Зависимости:** A, B завершены.
+
+**Ветка:** `feat/auth`
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| C1 | src/utils/password.ts (argon2id), src/utils/jwt.ts | `feat: add password hashing and JWT utils` |
+| C2 | src/services/auth/auth.service.ts | `feat: add AuthService` |
+| C3 | src/plugins/auth.ts (JWT verify, request.user) | `feat: add auth plugin` |
+| C4 | src/routes/auth.ts — register, login, logout, refresh | `feat: add auth routes` |
+| C5 | verify-email, forgot-password, reset-password | `feat: add email verification and password reset` |
+| C6 | Rate limiting на auth-роуты | `feat: add rate limiting to auth endpoints` |
+| C7 | Регистрация auth routes в app | `feat: register auth routes in app` |
+
+**Итого:** 7 коммитов. После завершения — PR в `dev`.
+
+---
+
+## Agent D: Profile & Subscription Middleware
+
+**Зависимости:** A, B, C.
+
+**Ветка:** `feat/profile-subscription`
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| D1 | src/plugins/subscription.ts | `feat: add subscription middleware` |
+| D2 | src/services/user/user.service.ts | `feat: add UserService` |
+| D3 | src/routes/profile.ts — GET, PATCH, GET :username | `feat: add profile routes` |
+| D4 | Интеграция user_stats в профиль | `feat: add stats to profile response` |
+| D5 | Регистрация profile routes в app | `feat: register profile routes` |
+
+**Итого:** 5 коммитов. После завершения — PR в `dev`.
+
+---
+
+## Agent E: Question Bank & Tests Service
+
+**Зависимости:** A, B, C, D, F (контракт LlmService).
+
+**Ветка:** `feat/tests-questions`
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| E1 | src/services/questions/question.service.ts | `feat: add QuestionService` |
+| E2 | src/services/tests/tests.service.ts — создание теста, снепшот | `feat: add TestsService create flow` |
+| E3 | tests.service — answer, finish, history | `feat: add test answer and finish flow` |
+| E4 | src/routes/tests.ts | `feat: add tests routes` |
+| E5 | Регистрация tests routes | `feat: register tests routes` |
+
+**Итого:** 5 коммитов. После завершения — PR в `dev`.
+
+---
+
+## Agent F: LLM Service & Fallback Logic
+
+**Зависимости:** A, B.
+
+**Ветка:** `feat/llm-service`
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| F1 | src/services/llm/llm.service.ts — конфиг, HTTP client | `feat: add LlmService base` |
+| F2 | generateQuestions с JSON Schema валидацией | `feat: add LLM question generation` |
+| F3 | Retry и fallback логика | `feat: add LLM retry and fallback` |
+| F4 | Интеграция question_cache_meta | `feat: log LLM metadata to question_cache_meta` |
+| F5 | Экспорт интерфейса для QuestionService | `feat: export LlmService interface` |
+
+**Итого:** 5 коммитов. После завершения — PR в `dev`.
+
+---
+
+## Agent G: Admin QA for Questions
+
+**Зависимости:** A, B, C, E (модель question_bank).
+
+**Ветка:** `feat/admin-qa`
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| G1 | src/services/admin/admin-question.service.ts | `feat: add AdminQuestionService` |
+| G2 | src/routes/admin/questions.ts | `feat: add admin questions routes` |
+| G3 | audit_logs при approve/reject/edit | `feat: add audit logging to admin actions` |
+| G4 | Регистрация admin routes | `feat: register admin routes` |
+
+**Итого:** 4 коммита. После завершения — PR в `dev`.
+
+---
+
+## Agent H: Tests & Quality
+
+**Зависимости:** Может стартовать после C (auth), наращивать по мере готовности других агентов.
+
+**Ветка:** `feat/testing`
+
+**Задачи и коммиты:**
+
+| # | Задача | Коммит |
+| - | - | - |
+| H1 | Vitest config, test-utils | `test: add Vitest config and test utils` |
+| H2 | AuthService unit tests | `test: add auth service tests` |
+| H3 | Auth routes integration tests | `test: add auth routes integration tests` |
+| H4 | TestsService и QuestionService tests | `test: add tests and questions service tests` |
+| H5 | LlmService unit tests (с моком) | `test: add LLM service tests` |
+| H6 | Admin routes integration tests | `test: add admin routes tests` |
+| H7 | Coverage ≥70%, npm script | `test: add coverage config` |
+
+**Итого:** 7 коммитов. После завершения — PR в `dev`.
+
+---
+
+## Рекомендуемый порядок запуска
+
+1. **Сразу:** Agent A и Agent B (в двух отдельных сессиях Cursor)
+2. **После A и B:** Agent C, D, F (три сессии)
+3. **После C, D, F:** Agent E, G (две сессии)
+4. **Параллельно волне 2–3:** Agent H (тесты по мере готовности API)
+
+---
+
+## Чеклист для каждого агента
+
+Перед каждым коммитом:
+
+- [ ] `npm run typecheck` проходит
+- [ ] Сообщение коммита по conventional commits
+- [ ] Нет `console.log`, только `logger`
+- [ ] Нет `any` без необходимости
+
+После завершения всех задач агента:
+
+- [ ] Создать PR в `dev`
+- [ ] Проверить, что не сломаны существующие тесты (если есть)
--- a/docker-compose.dev.yml
+++ b/docker-compose.dev.yml
@@ -0,0 +1,29 @@
+services:
+  postgres:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_USER: samreshu
+      POSTGRES_PASSWORD: samreshu_dev
+      POSTGRES_DB: samreshu
+    ports:
+      - "5432:5432"
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U samreshu -d samreshu"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  redis:
+    image: redis:7-alpine
+    ports:
+      - "6379:6379"
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+volumes:
+  pgdata:
--- a/drizzle.config.ts
+++ b/drizzle.config.ts
@@ -0,0 +1,13 @@
+import 'dotenv/config';
+import { defineConfig } from 'drizzle-kit';
+
+const databaseUrl = process.env.DATABASE_URL ?? 'postgresql://samreshu:samreshu_dev@localhost:5432/samreshu';
+
+export default defineConfig({
+  schema: './src/db/schema/*.ts',
+  out: './src/db/migrations',
+  dialect: 'postgresql',
+  dbCredentials: {
+    url: databaseUrl,
+  },
+});
--- a/package.json
+++ b/package.json
@@ -8,7 +8,7 @@
    "build": "tsc",
    "dev": "tsx watch src/server.ts",
    "start": "node dist/server.js",
-    "db:generate": "drizzle-kit generate --config=drizzle.config.ts",
+    "db:generate": "tsx node_modules/drizzle-kit/bin.cjs generate --config=drizzle.config.ts",
    "db:migrate": "tsx src/db/migrate.ts",
    "db:studio": "drizzle-kit studio",
    "db:seed": "tsx src/db/seed.ts",
--- a/1
+++ b/1
--- a/src/app.ts
+++ b/src/app.ts
@@ -0,0 +1,84 @@
+import Fastify, { FastifyInstance } from 'fastify';
+import { AppError } from './utils/errors.js';
+import databasePlugin from './plugins/database.js';
+import redisPlugin from './plugins/redis.js';
+import securityPlugin from './plugins/security.js';
+import rateLimitPlugin from './plugins/rateLimit.js';
+import authPlugin from './plugins/auth.js';
+import subscriptionPlugin from './plugins/subscription.js';
+import { authRoutes } from './routes/auth.js';
+import { profileRoutes } from './routes/profile.js';
+import { env } from './config/env.js';
+import { randomUUID } from 'node:crypto';
+
+export async function buildApp(): Promise<FastifyInstance> {
+  const isDev = env.NODE_ENV === 'development';
+
+  const app = Fastify({
+    logger: {
+      level: isDev ? 'debug' : 'info',
+      transport:
+        isDev
+          ? {
+              target: 'pino-pretty',
+              options: {
+                translateTime: 'HH:MM:ss Z',
+                ignore: 'pid,hostname',
+              },
+            }
+          : undefined,
+    },
+    requestIdHeader: 'x-request-id',
+    requestIdLogLabel: 'requestId',
+    genReqId: () => randomUUID(),
+  });
+
+  app.setErrorHandler((err: unknown, request, reply) => {
+    const error = err as Error & { statusCode?: number; validation?: unknown };
+    request.log.error({ err }, error.message);
+
+    if (err instanceof AppError) {
+      const statusCode = err.statusCode;
+      const payload = err.toJSON();
+      if (err.code === 'RATE_LIMIT_EXCEEDED' && 'retryAfter' in err) {
+        reply.header('Retry-After', String((err as AppError & { retryAfter?: number }).retryAfter ?? 60));
+      }
+      return reply.status(statusCode).send(payload);
+    }
+
+    if (error.validation) {
+      return reply.status(422).send({
+        error: {
+          code: 'VALIDATION_ERROR',
+          message: 'Validation failed',
+          details: error.validation,
+        },
+      });
+    }
+
+    const statusCode = error.statusCode ?? 500;
+    return reply.status(statusCode).send({
+      error: {
+        code: 'INTERNAL_ERROR',
+        message: env.NODE_ENV === 'production' ? 'Internal server error' : error.message,
+      },
+    });
+  });
+
+  app.addHook('onRequest', async (request, reply) => {
+    reply.header('x-request-id', request.id);
+  });
+
+  await app.register(redisPlugin);
+  await app.register(databasePlugin);
+  await app.register(securityPlugin);
+  await app.register(rateLimitPlugin);
+  await app.register(authPlugin);
+  await app.register(subscriptionPlugin);
+  await app.register(authRoutes, { prefix: '/auth' });
+  await app.register(profileRoutes, { prefix: '/profile' });
+
+  app.get('/health', async () => ({ status: 'ok', timestamp: new Date().toISOString() }));
+
+  return app;
+}
--- a/src/config/env.ts
+++ b/src/config/env.ts
@@ -0,0 +1,51 @@
+import { z } from 'zod';
+
+const envSchema = z.object({
+  NODE_ENV: z.enum(['development', 'test', 'production']).default('development'),
+  PORT: z.coerce.number().min(1).max(65535).default(3000),
+  HOST: z.string().default('0.0.0.0'),
+
+  DATABASE_URL: z.string().min(1),
+  REDIS_URL: z.string().min(1).default('redis://localhost:6379'),
+
+  JWT_SECRET: z.string().min(32),
+  JWT_ACCESS_TTL: z.string().default('15m'),
+  JWT_REFRESH_TTL: z.string().default('7d'),
+
+  LLM_BASE_URL: z.string().url().default('http://localhost:11434/v1'),
+  LLM_MODEL: z.string().default('qwen2.5:14b'),
+  LLM_FALLBACK_MODEL: z.string().optional(),
+  LLM_API_KEY: z.string().optional(),
+  LLM_TIMEOUT_MS: z.coerce.number().default(15000),
+  LLM_MAX_RETRIES: z.coerce.number().min(0).default(1),
+  LLM_RETRY_DELAY_MS: z.coerce.number().min(0).default(1000),
+  LLM_TEMPERATURE: z.coerce.number().min(0).max(2).default(0.7),
+  LLM_MAX_TOKENS: z.coerce.number().default(2048),
+
+  RATE_LIMIT_LOGIN: z.coerce.number().default(5),
+  RATE_LIMIT_REGISTER: z.coerce.number().default(3),
+  RATE_LIMIT_FORGOT_PASSWORD: z.coerce.number().default(3),
+  RATE_LIMIT_VERIFY_EMAIL: z.coerce.number().default(5),
+  RATE_LIMIT_API_AUTHED: z.coerce.number().default(100),
+  RATE_LIMIT_API_GUEST: z.coerce.number().default(30),
+
+  CORS_ORIGINS: z.string().default('http://localhost:5173'),
+  SENTRY_DSN: z.string().optional(),
+});
+
+export type Env = z.infer<typeof envSchema>;
+
+function parseEnv(): Env {
+  const result = envSchema.safeParse(process.env);
+  if (!result.success) {
+    const msg = result.error.flatten().fieldErrors;
+    throw new Error(`Invalid environment: ${JSON.stringify(msg)}`);
+  }
+  return result.data;
+}
+
+export const env = parseEnv();
+
+export function getCorsOrigins(): string[] {
+  return env.CORS_ORIGINS.split(',').map((s) => s.trim()).filter(Boolean);
+}
--- a/src/db/migrate.ts
+++ b/src/db/migrate.ts
@@ -0,0 +1,19 @@
+import { drizzle } from 'drizzle-orm/node-postgres';
+import { migrate } from 'drizzle-orm/node-postgres/migrator';
+import pg from 'pg';
+import { env } from '../config/env.js';
+
+const { Pool } = pg;
+
+async function runMigrations() {
+  const pool = new Pool({ connectionString: env.DATABASE_URL });
+  const db = drizzle(pool);
+
+  await migrate(db, { migrationsFolder: './src/db/migrations' });
+  await pool.end();
+}
+
+runMigrations().catch((err) => {
+  console.error('Migration failed:', err);
+  process.exit(1);
+});
--- a/src/db/migrations/0000_fearless_salo.sql
+++ b/src/db/migrations/0000_fearless_salo.sql
@@ -0,0 +1,246 @@
+CREATE TYPE "public"."level" AS ENUM('basic', 'beginner', 'intermediate', 'advanced', 'expert');--> statement-breakpoint
+CREATE TYPE "public"."plan" AS ENUM('free', 'pro');--> statement-breakpoint
+CREATE TYPE "public"."question_source" AS ENUM('llm_generated', 'manual');--> statement-breakpoint
+CREATE TYPE "public"."question_status" AS ENUM('pending', 'approved', 'rejected');--> statement-breakpoint
+CREATE TYPE "public"."question_type" AS ENUM('single_choice', 'multiple_select', 'true_false', 'short_text');--> statement-breakpoint
+CREATE TYPE "public"."report_status" AS ENUM('open', 'resolved', 'dismissed');--> statement-breakpoint
+CREATE TYPE "public"."self_level" AS ENUM('jun', 'mid', 'sen');--> statement-breakpoint
+CREATE TYPE "public"."stack" AS ENUM('html', 'css', 'js', 'ts', 'react', 'vue', 'nodejs', 'git', 'web_basics');--> statement-breakpoint
+CREATE TYPE "public"."subscription_status" AS ENUM('active', 'trialing', 'cancelled', 'expired');--> statement-breakpoint
+CREATE TYPE "public"."test_mode" AS ENUM('fixed', 'infinite', 'marathon');--> statement-breakpoint
+CREATE TYPE "public"."test_status" AS ENUM('in_progress', 'completed', 'abandoned');--> statement-breakpoint
+CREATE TYPE "public"."user_role" AS ENUM('guest', 'free', 'pro', 'admin');--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "users" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"email" varchar(255) NOT NULL,
+	"password_hash" varchar(255) NOT NULL,
+	"nickname" varchar(30) NOT NULL,
+	"avatar_url" varchar(500),
+	"country" varchar(100),
+	"city" varchar(100),
+	"self_level" "self_level",
+	"is_public" boolean DEFAULT true NOT NULL,
+	"role" "user_role" DEFAULT 'free' NOT NULL,
+	"email_verified_at" timestamp with time zone,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"updated_at" timestamp with time zone DEFAULT now() NOT NULL,
+	CONSTRAINT "users_email_unique" UNIQUE("email")
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "sessions" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"refresh_token_hash" varchar(255) NOT NULL,
+	"user_agent" varchar(500),
+	"ip_address" varchar(45),
+	"last_active_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"expires_at" timestamp with time zone NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "subscriptions" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"plan" "plan" NOT NULL,
+	"status" "subscription_status" NOT NULL,
+	"started_at" timestamp with time zone NOT NULL,
+	"expires_at" timestamp with time zone,
+	"cancelled_at" timestamp with time zone,
+	"payment_provider" varchar(50),
+	"external_id" varchar(255),
+	CONSTRAINT "subscriptions_user_id_unique" UNIQUE("user_id")
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "tests" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"stack" "stack" NOT NULL,
+	"level" "level" NOT NULL,
+	"question_count" integer NOT NULL,
+	"mode" "test_mode" DEFAULT 'fixed' NOT NULL,
+	"status" "test_status" DEFAULT 'in_progress' NOT NULL,
+	"score" integer,
+	"started_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"finished_at" timestamp with time zone,
+	"time_limit_seconds" integer
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "test_questions" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"test_id" uuid NOT NULL,
+	"question_bank_id" uuid,
+	"order_number" integer NOT NULL,
+	"type" "question_type" NOT NULL,
+	"question_text" text NOT NULL,
+	"options" jsonb,
+	"correct_answer" jsonb NOT NULL,
+	"explanation" text NOT NULL,
+	"user_answer" jsonb,
+	"is_correct" boolean,
+	"answered_at" timestamp with time zone
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "question_bank" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"stack" "stack" NOT NULL,
+	"level" "level" NOT NULL,
+	"type" "question_type" NOT NULL,
+	"question_text" text NOT NULL,
+	"options" jsonb,
+	"correct_answer" jsonb NOT NULL,
+	"explanation" text NOT NULL,
+	"status" "question_status" DEFAULT 'pending' NOT NULL,
+	"source" "question_source" NOT NULL,
+	"usage_count" integer DEFAULT 0 NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"approved_at" timestamp with time zone
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "question_cache_meta" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"question_bank_id" uuid NOT NULL,
+	"llm_model" varchar(100) NOT NULL,
+	"prompt_hash" varchar(64) NOT NULL,
+	"generation_time_ms" integer NOT NULL,
+	"raw_response" jsonb,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "question_reports" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"question_bank_id" uuid NOT NULL,
+	"user_id" uuid NOT NULL,
+	"reason" text NOT NULL,
+	"status" "report_status" DEFAULT 'open' NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"resolved_at" timestamp with time zone
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "user_stats" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"stack" "stack" NOT NULL,
+	"level" "level" NOT NULL,
+	"total_questions" integer DEFAULT 0 NOT NULL,
+	"correct_answers" integer DEFAULT 0 NOT NULL,
+	"tests_taken" integer DEFAULT 0 NOT NULL,
+	"last_test_at" timestamp with time zone,
+	CONSTRAINT "user_stats_user_id_stack_level_unique" UNIQUE("user_id","stack","level")
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "audit_logs" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"admin_id" uuid NOT NULL,
+	"action" varchar(100) NOT NULL,
+	"target_type" varchar(50) NOT NULL,
+	"target_id" uuid NOT NULL,
+	"details" jsonb,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "user_question_log" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"question_bank_id" uuid NOT NULL,
+	"seen_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "email_verification_codes" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"code" varchar(10) NOT NULL,
+	"expires_at" timestamp with time zone NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS "password_reset_tokens" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"token_hash" varchar(255) NOT NULL,
+	"expires_at" timestamp with time zone NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "sessions" ADD CONSTRAINT "sessions_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "subscriptions" ADD CONSTRAINT "subscriptions_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "tests" ADD CONSTRAINT "tests_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "test_questions" ADD CONSTRAINT "test_questions_test_id_tests_id_fk" FOREIGN KEY ("test_id") REFERENCES "public"."tests"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "test_questions" ADD CONSTRAINT "test_questions_question_bank_id_question_bank_id_fk" FOREIGN KEY ("question_bank_id") REFERENCES "public"."question_bank"("id") ON DELETE set null ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "question_cache_meta" ADD CONSTRAINT "question_cache_meta_question_bank_id_question_bank_id_fk" FOREIGN KEY ("question_bank_id") REFERENCES "public"."question_bank"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "question_reports" ADD CONSTRAINT "question_reports_question_bank_id_question_bank_id_fk" FOREIGN KEY ("question_bank_id") REFERENCES "public"."question_bank"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "question_reports" ADD CONSTRAINT "question_reports_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "user_stats" ADD CONSTRAINT "user_stats_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "audit_logs" ADD CONSTRAINT "audit_logs_admin_id_users_id_fk" FOREIGN KEY ("admin_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "user_question_log" ADD CONSTRAINT "user_question_log_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "user_question_log" ADD CONSTRAINT "user_question_log_question_bank_id_question_bank_id_fk" FOREIGN KEY ("question_bank_id") REFERENCES "public"."question_bank"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "email_verification_codes" ADD CONSTRAINT "email_verification_codes_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "password_reset_tokens" ADD CONSTRAINT "password_reset_tokens_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;
--- a/src/db/migrations/meta/0000_snapshot.json
+++ b/src/db/migrations/meta/0000_snapshot.json
--- a/src/db/migrations/meta/_journal.json
+++ b/src/db/migrations/meta/_journal.json
@@ -0,0 +1,13 @@
+{
+  "version": "7",
+  "dialect": "postgresql",
+  "entries": [
+    {
+      "idx": 0,
+      "version": "7",
+      "when": 1772620981431,
+      "tag": "0000_fearless_salo",
+      "breakpoints": true
+    }
+  ]
+}
--- a/src/db/schema/auditLogs.ts
+++ b/src/db/schema/auditLogs.ts
@@ -0,0 +1,18 @@
+import { pgTable, uuid, varchar, timestamp } from 'drizzle-orm/pg-core';
+import { jsonb } from 'drizzle-orm/pg-core';
+import { users } from './users.js';
+
+export const auditLogs = pgTable('audit_logs', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  adminId: uuid('admin_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  action: varchar('action', { length: 100 }).notNull(),
+  targetType: varchar('target_type', { length: 50 }).notNull(),
+  targetId: uuid('target_id').notNull(),
+  details: jsonb('details').$type<Record<string, unknown>>(),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+});
+
+export type AuditLog = typeof auditLogs.$inferSelect;
+export type NewAuditLog = typeof auditLogs.$inferInsert;
--- a/src/db/schema/enums.ts
+++ b/src/db/schema/enums.ts
@@ -0,0 +1,27 @@
+import { pgEnum } from 'drizzle-orm/pg-core';
+
+export const userRoleEnum = pgEnum('user_role', ['guest', 'free', 'pro', 'admin']);
+export const planEnum = pgEnum('plan', ['free', 'pro']);
+export const subscriptionStatusEnum = pgEnum('subscription_status', ['active', 'trialing', 'cancelled', 'expired']);
+export const stackEnum = pgEnum('stack', ['html', 'css', 'js', 'ts', 'react', 'vue', 'nodejs', 'git', 'web_basics']);
+export const levelEnum = pgEnum('level', ['basic', 'beginner', 'intermediate', 'advanced', 'expert']);
+export const testModeEnum = pgEnum('test_mode', ['fixed', 'infinite', 'marathon']);
+export const testStatusEnum = pgEnum('test_status', ['in_progress', 'completed', 'abandoned']);
+export const questionTypeEnum = pgEnum('question_type', ['single_choice', 'multiple_select', 'true_false', 'short_text']);
+export const questionStatusEnum = pgEnum('question_status', ['pending', 'approved', 'rejected']);
+export const questionSourceEnum = pgEnum('question_source', ['llm_generated', 'manual']);
+export const reportStatusEnum = pgEnum('report_status', ['open', 'resolved', 'dismissed']);
+export const selfLevelEnum = pgEnum('self_level', ['jun', 'mid', 'sen']);
+
+export type UserRole = (typeof userRoleEnum.enumValues)[number];
+export type Plan = (typeof planEnum.enumValues)[number];
+export type SubscriptionStatus = (typeof subscriptionStatusEnum.enumValues)[number];
+export type Stack = (typeof stackEnum.enumValues)[number];
+export type Level = (typeof levelEnum.enumValues)[number];
+export type TestMode = (typeof testModeEnum.enumValues)[number];
+export type TestStatus = (typeof testStatusEnum.enumValues)[number];
+export type QuestionType = (typeof questionTypeEnum.enumValues)[number];
+export type QuestionStatus = (typeof questionStatusEnum.enumValues)[number];
+export type QuestionSource = (typeof questionSourceEnum.enumValues)[number];
+export type ReportStatus = (typeof reportStatusEnum.enumValues)[number];
+export type SelfLevel = (typeof selfLevelEnum.enumValues)[number];
--- a/src/db/schema/index.ts
+++ b/src/db/schema/index.ts
@@ -0,0 +1,13 @@
+export * from './enums.js';
+export * from './users.js';
+export * from './sessions.js';
+export * from './subscriptions.js';
+export * from './tests.js';
+export * from './testQuestions.js';
+export * from './questionBank.js';
+export * from './questionCacheMeta.js';
+export * from './questionReports.js';
+export * from './userStats.js';
+export * from './auditLogs.js';
+export * from './userQuestionLog.js';
+export * from './verificationTokens.js';
--- a/src/db/schema/questionBank.ts
+++ b/src/db/schema/questionBank.ts
@@ -0,0 +1,22 @@
+import { pgTable, uuid, text, integer, timestamp } from 'drizzle-orm/pg-core';
+import { jsonb } from 'drizzle-orm/pg-core';
+import { stackEnum, levelEnum, questionTypeEnum, questionStatusEnum, questionSourceEnum } from './enums.js';
+
+export const questionBank = pgTable('question_bank', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  stack: stackEnum('stack').notNull(),
+  level: levelEnum('level').notNull(),
+  type: questionTypeEnum('type').notNull(),
+  questionText: text('question_text').notNull(),
+  options: jsonb('options').$type<Array<{ key: string; text: string }>>(),
+  correctAnswer: jsonb('correct_answer').$type<string | string[]>().notNull(),
+  explanation: text('explanation').notNull(),
+  status: questionStatusEnum('status').notNull().default('pending'),
+  source: questionSourceEnum('source').notNull(),
+  usageCount: integer('usage_count').notNull().default(0),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+  approvedAt: timestamp('approved_at', { withTimezone: true }),
+});
+
+export type QuestionBank = typeof questionBank.$inferSelect;
+export type NewQuestionBank = typeof questionBank.$inferInsert;
--- a/src/db/schema/questionCacheMeta.ts
+++ b/src/db/schema/questionCacheMeta.ts
@@ -0,0 +1,18 @@
+import { pgTable, uuid, varchar, integer, timestamp } from 'drizzle-orm/pg-core';
+import { jsonb } from 'drizzle-orm/pg-core';
+import { questionBank } from './questionBank.js';
+
+export const questionCacheMeta = pgTable('question_cache_meta', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  questionBankId: uuid('question_bank_id')
+    .notNull()
+    .references(() => questionBank.id, { onDelete: 'cascade' }),
+  llmModel: varchar('llm_model', { length: 100 }).notNull(),
+  promptHash: varchar('prompt_hash', { length: 64 }).notNull(),
+  generationTimeMs: integer('generation_time_ms').notNull(),
+  rawResponse: jsonb('raw_response').$type<unknown>(),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+});
+
+export type QuestionCacheMeta = typeof questionCacheMeta.$inferSelect;
+export type NewQuestionCacheMeta = typeof questionCacheMeta.$inferInsert;
--- a/src/db/schema/questionReports.ts
+++ b/src/db/schema/questionReports.ts
@@ -0,0 +1,21 @@
+import { pgTable, uuid, text, timestamp } from 'drizzle-orm/pg-core';
+import { reportStatusEnum } from './enums.js';
+import { questionBank } from './questionBank.js';
+import { users } from './users.js';
+
+export const questionReports = pgTable('question_reports', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  questionBankId: uuid('question_bank_id')
+    .notNull()
+    .references(() => questionBank.id, { onDelete: 'cascade' }),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  reason: text('reason').notNull(),
+  status: reportStatusEnum('status').notNull().default('open'),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+  resolvedAt: timestamp('resolved_at', { withTimezone: true }),
+});
+
+export type QuestionReport = typeof questionReports.$inferSelect;
+export type NewQuestionReport = typeof questionReports.$inferInsert;
--- a/src/db/schema/sessions.ts
+++ b/src/db/schema/sessions.ts
@@ -0,0 +1,18 @@
+import { pgTable, uuid, varchar, timestamp } from 'drizzle-orm/pg-core';
+import { users } from './users.js';
+
+export const sessions = pgTable('sessions', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  refreshTokenHash: varchar('refresh_token_hash', { length: 255 }).notNull(),
+  userAgent: varchar('user_agent', { length: 500 }),
+  ipAddress: varchar('ip_address', { length: 45 }),
+  lastActiveAt: timestamp('last_active_at', { withTimezone: true }).notNull().defaultNow(),
+  expiresAt: timestamp('expires_at', { withTimezone: true }).notNull(),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+});
+
+export type Session = typeof sessions.$inferSelect;
+export type NewSession = typeof sessions.$inferInsert;
--- a/src/db/schema/subscriptions.ts
+++ b/src/db/schema/subscriptions.ts
@@ -0,0 +1,21 @@
+import { pgTable, uuid, varchar, timestamp } from 'drizzle-orm/pg-core';
+import { planEnum, subscriptionStatusEnum } from './enums.js';
+import { users } from './users.js';
+
+export const subscriptions = pgTable('subscriptions', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' })
+    .unique(),
+  plan: planEnum('plan').notNull(),
+  status: subscriptionStatusEnum('status').notNull(),
+  startedAt: timestamp('started_at', { withTimezone: true }).notNull(),
+  expiresAt: timestamp('expires_at', { withTimezone: true }),
+  cancelledAt: timestamp('cancelled_at', { withTimezone: true }),
+  paymentProvider: varchar('payment_provider', { length: 50 }),
+  externalId: varchar('external_id', { length: 255 }),
+});
+
+export type Subscription = typeof subscriptions.$inferSelect;
+export type NewSubscription = typeof subscriptions.$inferInsert;
--- a/src/db/schema/testQuestions.ts
+++ b/src/db/schema/testQuestions.ts
@@ -0,0 +1,25 @@
+import { pgTable, uuid, text, integer, boolean, timestamp } from 'drizzle-orm/pg-core';
+import { jsonb } from 'drizzle-orm/pg-core';
+import { questionTypeEnum } from './enums.js';
+import { tests } from './tests.js';
+import { questionBank } from './questionBank.js';
+
+export const testQuestions = pgTable('test_questions', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  testId: uuid('test_id')
+    .notNull()
+    .references(() => tests.id, { onDelete: 'cascade' }),
+  questionBankId: uuid('question_bank_id').references(() => questionBank.id, { onDelete: 'set null' }),
+  orderNumber: integer('order_number').notNull(),
+  type: questionTypeEnum('type').notNull(),
+  questionText: text('question_text').notNull(),
+  options: jsonb('options').$type<Array<{ key: string; text: string }>>(),
+  correctAnswer: jsonb('correct_answer').$type<string | string[]>().notNull(),
+  explanation: text('explanation').notNull(),
+  userAnswer: jsonb('user_answer').$type<string | string[]>(),
+  isCorrect: boolean('is_correct'),
+  answeredAt: timestamp('answered_at', { withTimezone: true }),
+});
+
+export type TestQuestion = typeof testQuestions.$inferSelect;
+export type NewTestQuestion = typeof testQuestions.$inferInsert;
--- a/src/db/schema/tests.ts
+++ b/src/db/schema/tests.ts
@@ -0,0 +1,22 @@
+import { pgTable, uuid, integer, timestamp } from 'drizzle-orm/pg-core';
+import { stackEnum, levelEnum, testModeEnum, testStatusEnum } from './enums.js';
+import { users } from './users.js';
+
+export const tests = pgTable('tests', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  stack: stackEnum('stack').notNull(),
+  level: levelEnum('level').notNull(),
+  questionCount: integer('question_count').notNull(),
+  mode: testModeEnum('mode').notNull().default('fixed'),
+  status: testStatusEnum('status').notNull().default('in_progress'),
+  score: integer('score'),
+  startedAt: timestamp('started_at', { withTimezone: true }).notNull().defaultNow(),
+  finishedAt: timestamp('finished_at', { withTimezone: true }),
+  timeLimitSeconds: integer('time_limit_seconds'),
+});
+
+export type Test = typeof tests.$inferSelect;
+export type NewTest = typeof tests.$inferInsert;
--- a/src/db/schema/userQuestionLog.ts
+++ b/src/db/schema/userQuestionLog.ts
@@ -0,0 +1,17 @@
+import { pgTable, uuid, timestamp } from 'drizzle-orm/pg-core';
+import { users } from './users.js';
+import { questionBank } from './questionBank.js';
+
+export const userQuestionLog = pgTable('user_question_log', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  questionBankId: uuid('question_bank_id')
+    .notNull()
+    .references(() => questionBank.id, { onDelete: 'cascade' }),
+  seenAt: timestamp('seen_at', { withTimezone: true }).notNull().defaultNow(),
+});
+
+export type UserQuestionLog = typeof userQuestionLog.$inferSelect;
+export type NewUserQuestionLog = typeof userQuestionLog.$inferInsert;
--- a/src/db/schema/userStats.ts
+++ b/src/db/schema/userStats.ts
@@ -0,0 +1,26 @@
+import { pgTable, uuid, integer, timestamp } from 'drizzle-orm/pg-core';
+import { unique } from 'drizzle-orm/pg-core';
+import { stackEnum, levelEnum } from './enums.js';
+import { users } from './users.js';
+
+export const userStats = pgTable(
+  'user_stats',
+  {
+    id: uuid('id').primaryKey().defaultRandom(),
+    userId: uuid('user_id')
+      .notNull()
+      .references(() => users.id, { onDelete: 'cascade' }),
+    stack: stackEnum('stack').notNull(),
+    level: levelEnum('level').notNull(),
+    totalQuestions: integer('total_questions').notNull().default(0),
+    correctAnswers: integer('correct_answers').notNull().default(0),
+    testsTaken: integer('tests_taken').notNull().default(0),
+    lastTestAt: timestamp('last_test_at', { withTimezone: true }),
+  },
+  (t) => ({
+    userStackLevelUnique: unique().on(t.userId, t.stack, t.level),
+  })
+);
+
+export type UserStat = typeof userStats.$inferSelect;
+export type NewUserStat = typeof userStats.$inferInsert;
--- a/src/db/schema/users.ts
+++ b/src/db/schema/users.ts
@@ -0,0 +1,21 @@
+import { pgTable, uuid, varchar, timestamp, boolean } from 'drizzle-orm/pg-core';
+import { userRoleEnum, selfLevelEnum } from './enums.js';
+
+export const users = pgTable('users', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  email: varchar('email', { length: 255 }).notNull().unique(),
+  passwordHash: varchar('password_hash', { length: 255 }).notNull(),
+  nickname: varchar('nickname', { length: 30 }).notNull(),
+  avatarUrl: varchar('avatar_url', { length: 500 }),
+  country: varchar('country', { length: 100 }),
+  city: varchar('city', { length: 100 }),
+  selfLevel: selfLevelEnum('self_level'),
+  isPublic: boolean('is_public').notNull().default(true),
+  role: userRoleEnum('role').notNull().default('free'),
+  emailVerifiedAt: timestamp('email_verified_at', { withTimezone: true }),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+  updatedAt: timestamp('updated_at', { withTimezone: true }).notNull().defaultNow(),
+});
+
+export type User = typeof users.$inferSelect;
+export type NewUser = typeof users.$inferInsert;
--- a/src/db/schema/verificationTokens.ts
+++ b/src/db/schema/verificationTokens.ts
@@ -0,0 +1,22 @@
+import { pgTable, uuid, varchar, timestamp } from 'drizzle-orm/pg-core';
+import { users } from './users.js';
+
+export const emailVerificationCodes = pgTable('email_verification_codes', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  code: varchar('code', { length: 10 }).notNull(),
+  expiresAt: timestamp('expires_at', { withTimezone: true }).notNull(),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+});
+
+export const passwordResetTokens = pgTable('password_reset_tokens', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  tokenHash: varchar('token_hash', { length: 255 }).notNull(),
+  expiresAt: timestamp('expires_at', { withTimezone: true }).notNull(),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+});
--- a/src/db/seed.ts
+++ b/src/db/seed.ts
@@ -0,0 +1,47 @@
+import 'dotenv/config';
+import { drizzle } from 'drizzle-orm/node-postgres';
+import { eq } from 'drizzle-orm';
+import pg from 'pg';
+import argon2 from 'argon2';
+import { env } from '../config/env.js';
+import { users } from './schema/index.js';
+
+const { Pool } = pg;
+
+const TEST_USER = {
+  email: 'test@example.com',
+  password: 'TestPassword123!',
+  nickname: 'TestUser',
+};
+
+async function runSeed() {
+  const pool = new Pool({ connectionString: env.DATABASE_URL });
+  const db = drizzle(pool);
+
+  if (env.NODE_ENV !== 'development') {
+    await pool.end();
+    return;
+  }
+
+  const existing = await db.select().from(users).where(eq(users.email, TEST_USER.email)).limit(1);
+  if (existing.length > 0) {
+    await pool.end();
+    return;
+  }
+
+  const passwordHash = await argon2.hash(TEST_USER.password);
+  await db.insert(users).values({
+    email: TEST_USER.email,
+    passwordHash,
+    nickname: TEST_USER.nickname,
+    role: 'free',
+    emailVerifiedAt: new Date(),
+  });
+
+  await pool.end();
+}
+
+runSeed().catch((err) => {
+  console.error('Seed failed:', err);
+  process.exit(1);
+});
--- a/src/plugins/auth.ts
+++ b/src/plugins/auth.ts
@@ -0,0 +1,42 @@
+import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
+import fp from 'fastify-plugin';
+import { verifyToken, isAccessPayload } from '../utils/jwt.js';
+import { unauthorized } from '../utils/errors.js';
+
+declare module 'fastify' {
+  interface FastifyInstance {
+    authenticate: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
+  }
+  interface FastifyRequest {
+    user?: { id: string; email: string };
+  }
+}
+
+export async function authenticate(req: FastifyRequest, _reply: FastifyReply): Promise<void> {
+  const authHeader = req.headers.authorization;
+
+  if (!authHeader?.startsWith('Bearer ')) {
+    throw unauthorized('Missing or invalid authorization header');
+  }
+
+  const token = authHeader.slice(7);
+
+  try {
+    const payload = await verifyToken(token);
+
+    if (!isAccessPayload(payload)) {
+      throw unauthorized('Invalid token type');
+    }
+
+    req.user = { id: payload.sub, email: payload.email };
+  } catch {
+    throw unauthorized('Invalid or expired token');
+  }
+}
+
+const authPlugin = async (app: FastifyInstance) => {
+  app.decorateRequest('user', undefined);
+  app.decorate('authenticate', authenticate);
+};
+
+export default fp(authPlugin, { name: 'auth' });
--- a/src/plugins/database.ts
+++ b/src/plugins/database.ts
@@ -0,0 +1,33 @@
+import { FastifyInstance, FastifyPluginAsync } from 'fastify';
+import { drizzle } from 'drizzle-orm/node-postgres';
+import pg from 'pg';
+import fp from 'fastify-plugin';
+import { env } from '../config/env.js';
+import * as schema from '../db/schema/index.js';
+
+const { Pool } = pg;
+
+declare module 'fastify' {
+  interface FastifyInstance {
+    db: ReturnType<typeof drizzle<typeof schema>>;
+  }
+}
+
+const databasePlugin: FastifyPluginAsync = async (app: FastifyInstance) => {
+  const pool = new Pool({
+    connectionString: env.DATABASE_URL,
+    max: 10,
+    idleTimeoutMillis: 30000,
+    connectionTimeoutMillis: 5000,
+  });
+
+  const db = drizzle(pool, { schema });
+
+  app.decorate('db', db);
+
+  app.addHook('onClose', async () => {
+    await pool.end();
+  });
+};
+
+export default fp(databasePlugin, { name: 'database' });
--- a/src/plugins/rateLimit.ts
+++ b/src/plugins/rateLimit.ts
@@ -0,0 +1,60 @@
+import { FastifyInstance, FastifyPluginAsync } from 'fastify';
+import rateLimit from '@fastify/rate-limit';
+import fp from 'fastify-plugin';
+import { env } from '../config/env.js';
+
+declare module 'fastify' {
+  interface FastifyInstance {
+    rateLimitOptions: {
+      login: { max: number; timeWindow: string };
+      register: { max: number; timeWindow: string };
+      forgotPassword: { max: number; timeWindow: string };
+      verifyEmail: { max: number; timeWindow: string };
+      apiAuthed: { max: number; timeWindow: string };
+      apiGuest: { max: number; timeWindow: string };
+    };
+  }
+}
+
+const rateLimitPlugin: FastifyPluginAsync = async (app: FastifyInstance) => {
+  const options = {
+    login: { max: env.RATE_LIMIT_LOGIN, timeWindow: '15 minutes' },
+    register: { max: env.RATE_LIMIT_REGISTER, timeWindow: '1 hour' },
+    forgotPassword: { max: env.RATE_LIMIT_FORGOT_PASSWORD, timeWindow: '1 hour' },
+    verifyEmail: { max: env.RATE_LIMIT_VERIFY_EMAIL, timeWindow: '15 minutes' },
+    apiAuthed: { max: env.RATE_LIMIT_API_AUTHED, timeWindow: '1 minute' },
+    apiGuest: { max: env.RATE_LIMIT_API_GUEST, timeWindow: '1 minute' },
+  };
+
+  app.decorate('rateLimitOptions', options);
+
+  await app.register(rateLimit, {
+    global: false,
+    max: options.apiGuest.max,
+    timeWindow: options.apiGuest.timeWindow,
+    keyGenerator: (req) => {
+      return (req.ip ?? 'unknown') as string;
+    },
+    redis: app.redis,
+    addHeadersOnExceeding: {
+      'x-ratelimit-limit': true,
+      'x-ratelimit-remaining': true,
+      'x-ratelimit-reset': true,
+    },
+    addHeaders: {
+      'x-ratelimit-limit': true,
+      'x-ratelimit-remaining': true,
+      'x-ratelimit-reset': true,
+      'retry-after': true,
+    },
+    errorResponseBuilder: (_req, context) => ({
+      error: {
+        code: 'RATE_LIMIT_EXCEEDED',
+        message: 'Too many requests, please try again later',
+        retryAfter: context.ttl,
+      },
+    }),
+  });
+};
+
+export default fp(rateLimitPlugin, { name: 'rateLimit', dependencies: ['redis'] });
--- a/src/plugins/redis.ts
+++ b/src/plugins/redis.ts
@@ -0,0 +1,32 @@
+import { FastifyInstance, FastifyPluginAsync } from 'fastify';
+import { Redis } from 'ioredis';
+import fp from 'fastify-plugin';
+import { env } from '../config/env.js';
+
+declare module 'fastify' {
+  interface FastifyInstance {
+    redis: Redis;
+  }
+}
+
+const redisPlugin: FastifyPluginAsync = async (app: FastifyInstance) => {
+  const redis = new Redis(env.REDIS_URL, {
+    maxRetriesPerRequest: 3,
+    retryStrategy(times: number) {
+      const delay = Math.min(times * 100, 3000);
+      return delay;
+    },
+  });
+
+  redis.on('error', (err: Error) => {
+    app.log.error({ err }, 'Redis connection error');
+  });
+
+  app.decorate('redis', redis);
+
+  app.addHook('onClose', async () => {
+    await redis.quit();
+  });
+};
+
+export default fp(redisPlugin, { name: 'redis' });
--- a/src/plugins/security.ts
+++ b/src/plugins/security.ts
@@ -0,0 +1,21 @@
+import { FastifyInstance, FastifyPluginAsync } from 'fastify';
+import helmet from '@fastify/helmet';
+import cors from '@fastify/cors';
+import fp from 'fastify-plugin';
+import { getCorsOrigins } from '../config/env.js';
+
+const securityPlugin: FastifyPluginAsync = async (app: FastifyInstance) => {
+  await app.register(helmet, {
+    contentSecurityPolicy: false,
+    crossOriginEmbedderPolicy: false,
+  });
+
+  await app.register(cors, {
+    origin: getCorsOrigins(),
+    credentials: true,
+    methods: ['GET', 'POST', 'PATCH', 'DELETE', 'PUT', 'OPTIONS'],
+    allowedHeaders: ['Content-Type', 'Authorization'],
+  });
+};
+
+export default fp(securityPlugin, { name: 'security' });
--- a/src/plugins/subscription.ts
+++ b/src/plugins/subscription.ts
@@ -0,0 +1,71 @@
+import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
+import fp from 'fastify-plugin';
+import { eq } from 'drizzle-orm';
+import { subscriptions } from '../db/schema/subscriptions.js';
+import { forbidden } from '../utils/errors.js';
+
+export type SubscriptionInfo = {
+  plan: 'free' | 'pro';
+  status: 'active' | 'trialing' | 'cancelled' | 'expired';
+  isPro: boolean;
+  expiresAt: Date | null;
+};
+
+declare module 'fastify' {
+  interface FastifyRequest {
+    subscription?: SubscriptionInfo | null;
+  }
+  interface FastifyInstance {
+    withSubscription: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
+    requirePro: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
+  }
+}
+
+async function loadSubscription(db: FastifyInstance['db'], userId: string): Promise<SubscriptionInfo | null> {
+  const [sub] = await db
+    .select()
+    .from(subscriptions)
+    .where(eq(subscriptions.userId, userId))
+    .limit(1);
+
+  if (!sub) return null;
+
+  const now = new Date();
+  const isExpired = sub.expiresAt && sub.expiresAt < now;
+  const isPro =
+    sub.plan === 'pro' &&
+    (sub.status === 'active' || sub.status === 'trialing') &&
+    !isExpired;
+
+  return {
+    plan: sub.plan as 'free' | 'pro',
+    status: sub.status as SubscriptionInfo['status'],
+    isPro,
+    expiresAt: sub.expiresAt,
+  };
+}
+
+export async function requirePro(req: FastifyRequest, _reply: FastifyReply): Promise<void> {
+  const sub = req.subscription;
+
+  if (!sub?.isPro) {
+    throw forbidden('Pro subscription required');
+  }
+}
+
+const subscriptionPlugin = async (app: FastifyInstance) => {
+  app.decorateRequest('subscription', undefined);
+
+  app.decorate('withSubscription', async (req: FastifyRequest, _reply: FastifyReply) => {
+    if (!req.user?.id) return;
+    const sub = await loadSubscription(app.db, req.user.id);
+    req.subscription = sub;
+  });
+
+  app.decorate('requirePro', requirePro);
+};
+
+export default fp(subscriptionPlugin, {
+  name: 'subscription',
+  dependencies: ['database', 'auth'],
+});
--- a/src/routes/auth.ts
+++ b/src/routes/auth.ts
@@ -0,0 +1,168 @@
+import type { FastifyInstance } from 'fastify';
+import { AuthService } from '../services/auth/auth.service.js';
+
+const registerSchema = {
+  body: {
+    type: 'object',
+    required: ['email', 'password', 'nickname'],
+    properties: {
+      email: { type: 'string', minLength: 1 },
+      password: { type: 'string', minLength: 8 },
+      nickname: { type: 'string', minLength: 2, maxLength: 30 },
+    },
+  },
+};
+
+const loginSchema = {
+  body: {
+    type: 'object',
+    required: ['email', 'password'],
+    properties: {
+      email: { type: 'string', minLength: 1 },
+      password: { type: 'string' },
+    },
+  },
+};
+
+const refreshTokenSchema = {
+  body: {
+    type: 'object',
+    required: ['refreshToken'],
+    properties: {
+      refreshToken: { type: 'string' },
+    },
+  },
+};
+
+const logoutSchema = refreshTokenSchema;
+
+const verifyEmailSchema = {
+  body: {
+    type: 'object',
+    required: ['userId', 'code'],
+    properties: {
+      userId: { type: 'string', minLength: 1 },
+      code: { type: 'string', minLength: 1, maxLength: 10 },
+    },
+  },
+};
+
+const forgotPasswordSchema = {
+  body: {
+    type: 'object',
+    required: ['email'],
+    properties: {
+      email: { type: 'string', minLength: 1 },
+    },
+  },
+};
+
+const resetPasswordSchema = {
+  body: {
+    type: 'object',
+    required: ['token', 'newPassword'],
+    properties: {
+      token: { type: 'string' },
+      newPassword: { type: 'string', minLength: 8 },
+    },
+  },
+};
+
+export async function authRoutes(app: FastifyInstance) {
+  const authService = new AuthService(app.db);
+  const { rateLimitOptions } = app;
+
+  app.post(
+    '/register',
+    { schema: registerSchema, config: { rateLimit: rateLimitOptions.register } },
+    async (req, reply) => {
+      const body = req.body as { email: string; password: string; nickname: string };
+      const { userId, verificationCode } = await authService.register(body);
+
+      return reply.status(201).send({
+        userId,
+        message: 'Registration successful. Please verify your email.',
+        verificationCode,
+      });
+    },
+  );
+
+  app.post(
+    '/login',
+    { schema: loginSchema, config: { rateLimit: rateLimitOptions.login } },
+    async (req, reply) => {
+      const body = req.body as { email: string; password: string };
+      const userAgent = req.headers['user-agent'];
+      const ipAddress = req.ip;
+
+      const result = await authService.login({
+        email: body.email,
+        password: body.password,
+        userAgent,
+        ipAddress,
+      });
+
+      return reply.send(result);
+    },
+  );
+
+  app.post(
+    '/logout',
+    { schema: logoutSchema, config: { rateLimit: rateLimitOptions.apiGuest } },
+    async (req, reply) => {
+      const body = req.body as { refreshToken: string };
+      await authService.logout(body.refreshToken);
+      return reply.status(204).send();
+    },
+  );
+
+  app.post(
+    '/refresh',
+    { schema: refreshTokenSchema, config: { rateLimit: rateLimitOptions.apiGuest } },
+    async (req, reply) => {
+      const body = req.body as { refreshToken: string };
+      const userAgent = req.headers['user-agent'];
+      const ipAddress = req.ip;
+
+      const result = await authService.refresh({
+        refreshToken: body.refreshToken,
+        userAgent,
+        ipAddress,
+      });
+
+      return reply.send(result);
+    },
+  );
+
+  app.post(
+    '/verify-email',
+    { schema: verifyEmailSchema, config: { rateLimit: rateLimitOptions.verifyEmail } },
+    async (req, reply) => {
+      const body = req.body as { userId: string; code: string };
+      await authService.verifyEmail(body.userId, body.code);
+      return reply.send({ message: 'Email verified successfully' });
+    },
+  );
+
+  app.post(
+    '/forgot-password',
+    { schema: forgotPasswordSchema, config: { rateLimit: rateLimitOptions.forgotPassword } },
+    async (req, reply) => {
+      const body = req.body as { email: string };
+      await authService.forgotPassword(body.email);
+      return reply.send({
+        message: 'If the email exists, a reset link has been sent.',
+      });
+    },
+  );
+
+  app.post(
+    '/reset-password',
+    { schema: resetPasswordSchema, config: { rateLimit: rateLimitOptions.forgotPassword } },
+    async (req, reply) => {
+      const body = req.body as { token: string; newPassword: string };
+      await authService.resetPassword(body.token, body.newPassword);
+      return reply.send({ message: 'Password reset successfully' });
+    },
+  );
+}
--- a/src/routes/profile.ts
+++ b/src/routes/profile.ts
@@ -0,0 +1,73 @@
+import type { FastifyInstance } from 'fastify';
+import { UserService } from '../services/user/user.service.js';
+
+const patchProfileSchema = {
+  body: {
+    type: 'object',
+    properties: {
+      nickname: { type: 'string', minLength: 2, maxLength: 30 },
+      avatarUrl: { type: ['string', 'null'], maxLength: 500 },
+      country: { type: ['string', 'null'], maxLength: 100 },
+      city: { type: ['string', 'null'], maxLength: 100 },
+      selfLevel: { type: ['string', 'null'], enum: ['jun', 'mid', 'sen'] },
+      isPublic: { type: 'boolean' },
+    },
+    additionalProperties: false,
+  },
+};
+
+const usernameParamsSchema = {
+  params: {
+    type: 'object',
+    required: ['username'],
+    properties: {
+      username: { type: 'string', minLength: 2, maxLength: 30 },
+    },
+  },
+};
+
+export async function profileRoutes(app: FastifyInstance) {
+  const userService = new UserService(app.db);
+  const { rateLimitOptions } = app;
+
+  app.get(
+    '/',
+    {
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate, app.withSubscription],
+    },
+    async (req, reply) => {
+      const userId = req.user!.id;
+      const profile = await userService.getPrivateProfile(userId);
+      return reply.send(profile);
+    },
+  );
+
+  app.patch(
+    '/',
+    {
+      schema: patchProfileSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate],
+    },
+    async (req, reply) => {
+      const userId = req.user!.id;
+      const body = req.body as Parameters<UserService['updateProfile']>[1];
+      const profile = await userService.updateProfile(userId, body);
+      return reply.send(profile);
+    },
+  );
+
+  app.get(
+    '/:username',
+    {
+      schema: usernameParamsSchema,
+      config: { rateLimit: rateLimitOptions.apiGuest },
+    },
+    async (req, reply) => {
+      const { username } = req.params as { username: string };
+      const profile = await userService.getPublicProfile(username);
+      return reply.send(profile);
+    },
+  );
+}
--- a/src/server.ts
+++ b/src/server.ts
@@ -0,0 +1,26 @@
+import 'dotenv/config';
+import { buildApp } from './app.js';
+import { env } from './config/env.js';
+
+async function main() {
+  const app = await buildApp();
+
+  try {
+    await app.listen({ port: env.PORT, host: env.HOST });
+    app.log.info({ port: env.PORT }, 'Server started');
+  } catch (err) {
+    app.log.error(err);
+    process.exit(1);
+  }
+
+  const shutdown = async () => {
+    app.log.info('Shutting down...');
+    await app.close();
+    process.exit(0);
+  };
+
+  process.on('SIGINT', shutdown);
+  process.on('SIGTERM', shutdown);
+}
+
+main();
--- a/src/services/auth/auth.service.ts
+++ b/src/services/auth/auth.service.ts
@@ -0,0 +1,304 @@
+import { eq, and, gt } from 'drizzle-orm';
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres';
+import type * as schema from '../../db/schema/index.js';
+import { users, sessions, emailVerificationCodes, passwordResetTokens } from '../../db/schema/index.js';
+import { hashPassword, verifyPassword } from '../../utils/password.js';
+import {
+  signAccessToken,
+  signRefreshToken,
+  verifyToken,
+  isRefreshPayload,
+  hashToken,
+} from '../../utils/jwt.js';
+import {
+  AppError,
+  conflict,
+  unauthorized,
+  notFound,
+  ERROR_CODES,
+} from '../../utils/errors.js';
+import { randomBytes, randomUUID } from 'node:crypto';
+
+type Db = NodePgDatabase<typeof schema>;
+
+export interface RegisterInput {
+  email: string;
+  password: string;
+  nickname: string;
+}
+
+export interface LoginInput {
+  email: string;
+  password: string;
+  userAgent?: string;
+  ipAddress?: string;
+}
+
+export interface LoginResult {
+  accessToken: string;
+  refreshToken: string;
+  expiresIn: number;
+}
+
+export interface RefreshInput {
+  refreshToken: string;
+  userAgent?: string;
+  ipAddress?: string;
+}
+
+export interface ForgotPasswordResult {
+  token: string;
+  expiresAt: Date;
+}
+
+const REFRESH_TTL_MS = 7 * 24 * 60 * 60 * 1000;
+const VERIFICATION_CODE_LENGTH = 6;
+const VERIFICATION_CODE_TTL_MS = 15 * 60 * 1000;
+const RESET_TOKEN_TTL_MS = 60 * 60 * 1000;
+
+export class AuthService {
+  constructor(private readonly db: Db) {}
+
+  async register(input: RegisterInput): Promise<{ userId: string; verificationCode: string }> {
+    const [existing] = await this.db
+      .select()
+      .from(users)
+      .where(eq(users.email, input.email.toLowerCase().trim()))
+      .limit(1);
+
+    if (existing) {
+      throw conflict(ERROR_CODES.EMAIL_TAKEN, 'Email already registered');
+    }
+
+    const [nicknameConflict] = await this.db
+      .select()
+      .from(users)
+      .where(eq(users.nickname, input.nickname.trim()))
+      .limit(1);
+
+    if (nicknameConflict) {
+      throw conflict(ERROR_CODES.NICKNAME_TAKEN, 'Nickname already taken');
+    }
+
+    const passwordHash = await hashPassword(input.password);
+
+    const [user] = await this.db
+      .insert(users)
+      .values({
+        email: input.email.toLowerCase().trim(),
+        passwordHash,
+        nickname: input.nickname.trim(),
+      })
+      .returning({ id: users.id });
+
+    if (!user) {
+      throw new AppError(ERROR_CODES.INTERNAL_ERROR, 'Failed to create user', 500);
+    }
+
+    const code = randomBytes(VERIFICATION_CODE_LENGTH)
+      .toString('hex')
+      .slice(0, VERIFICATION_CODE_LENGTH)
+      .toUpperCase();
+    const expiresAt = new Date(Date.now() + VERIFICATION_CODE_TTL_MS);
+
+    await this.db.insert(emailVerificationCodes).values({
+      userId: user.id,
+      code,
+      expiresAt,
+    });
+
+    return { userId: user.id, verificationCode: code };
+  }
+
+  async login(input: LoginInput): Promise<LoginResult> {
+    const [user] = await this.db
+      .select()
+      .from(users)
+      .where(eq(users.email, input.email.toLowerCase().trim()))
+      .limit(1);
+
+    if (!user || !(await verifyPassword(user.passwordHash, input.password))) {
+      throw unauthorized('Invalid email or password');
+    }
+
+    const [accessToken, refreshToken] = await Promise.all([
+      signAccessToken({ sub: user.id, email: user.email }),
+      signRefreshToken({ sub: user.id, sid: randomUUID() }),
+    ]);
+
+    const refreshHash = hashToken(refreshToken);
+    const expiresAt = new Date(Date.now() + REFRESH_TTL_MS);
+
+    await this.db.insert(sessions).values({
+      userId: user.id,
+      refreshTokenHash: refreshHash,
+      userAgent: input.userAgent ?? null,
+      ipAddress: input.ipAddress ?? null,
+      expiresAt,
+    });
+
+    return {
+      accessToken,
+      refreshToken,
+      expiresIn: Math.floor(REFRESH_TTL_MS / 1000),
+    };
+  }
+
+  async logout(refreshToken: string): Promise<void> {
+    const hash = hashToken(refreshToken);
+    await this.db.delete(sessions).where(eq(sessions.refreshTokenHash, hash));
+  }
+
+  async refresh(input: RefreshInput): Promise<LoginResult> {
+    const payload = await verifyToken(input.refreshToken);
+
+    if (!isRefreshPayload(payload)) {
+      throw unauthorized('Invalid refresh token');
+    }
+
+    const hash = hashToken(input.refreshToken);
+
+    const [session] = await this.db
+      .select()
+      .from(sessions)
+      .where(and(eq(sessions.refreshTokenHash, hash), gt(sessions.expiresAt, new Date())))
+      .limit(1);
+
+    if (!session) {
+      throw new AppError(ERROR_CODES.INVALID_REFRESH_TOKEN, 'Invalid or expired refresh token', 401);
+    }
+
+    await this.db.delete(sessions).where(eq(sessions.id, session.id));
+
+    const [user] = await this.db.select().from(users).where(eq(users.id, session.userId)).limit(1);
+
+    if (!user) {
+      throw notFound('User not found');
+    }
+
+    const [accessToken, newRefreshToken] = await Promise.all([
+      signAccessToken({ sub: user.id, email: user.email }),
+      signRefreshToken({ sub: user.id, sid: randomUUID() }),
+    ]);
+
+    const newHash = hashToken(newRefreshToken);
+    const expiresAt = new Date(Date.now() + REFRESH_TTL_MS);
+
+    await this.db.insert(sessions).values({
+      userId: user.id,
+      refreshTokenHash: newHash,
+      userAgent: input.userAgent ?? session.userAgent,
+      ipAddress: input.ipAddress ?? session.ipAddress,
+      expiresAt,
+    });
+
+    return {
+      accessToken,
+      refreshToken: newRefreshToken,
+      expiresIn: Math.floor(REFRESH_TTL_MS / 1000),
+    };
+  }
+
+  async verifyEmail(userId: string, verificationCode: string): Promise<void> {
+    const codeUpper = verificationCode.toUpperCase();
+    const [record] = await this.db
+      .select()
+      .from(emailVerificationCodes)
+      .where(
+        and(
+          eq(emailVerificationCodes.userId, userId),
+          eq(emailVerificationCodes.code, codeUpper),
+        ),
+      )
+      .limit(1);
+
+    if (!record) {
+      throw new AppError(ERROR_CODES.INVALID_CODE, 'Invalid or expired verification code', 400);
+    }
+
+    if (record.expiresAt < new Date()) {
+      await this.db
+        .delete(emailVerificationCodes)
+        .where(eq(emailVerificationCodes.id, record.id));
+      throw new AppError(ERROR_CODES.INVALID_CODE, 'Verification code expired', 400);
+    }
+
+    const [user] = await this.db.select().from(users).where(eq(users.id, userId)).limit(1);
+
+    if (!user) {
+      throw notFound('User not found');
+    }
+
+    if (user.emailVerifiedAt) {
+      throw new AppError(ERROR_CODES.ALREADY_VERIFIED, 'Email already verified', 400);
+    }
+
+    await this.db
+      .update(users)
+      .set({ emailVerifiedAt: new Date(), updatedAt: new Date() })
+      .where(eq(users.id, userId));
+
+    await this.db
+      .delete(emailVerificationCodes)
+      .where(eq(emailVerificationCodes.userId, userId));
+  }
+
+  async forgotPassword(email: string): Promise<ForgotPasswordResult> {
+    const [user] = await this.db
+      .select()
+      .from(users)
+      .where(eq(users.email, email.toLowerCase().trim()))
+      .limit(1);
+
+    if (!user) {
+      return {
+        token: '',
+        expiresAt: new Date(Date.now() + RESET_TOKEN_TTL_MS),
+      };
+    }
+
+    const token = randomBytes(32).toString('hex');
+    const tokenHash = hashToken(token);
+    const expiresAt = new Date(Date.now() + RESET_TOKEN_TTL_MS);
+
+    await this.db.insert(passwordResetTokens).values({
+      userId: user.id,
+      tokenHash,
+      expiresAt,
+    });
+
+    return { token, expiresAt };
+  }
+
+  async resetPassword(token: string, newPassword: string): Promise<void> {
+    const tokenHash = hashToken(token);
+
+    const [record] = await this.db
+      .select()
+      .from(passwordResetTokens)
+      .where(eq(passwordResetTokens.tokenHash, tokenHash))
+      .limit(1);
+
+    if (!record) {
+      throw new AppError(ERROR_CODES.INVALID_RESET_TOKEN, 'Invalid or expired reset token', 400);
+    }
+
+    if (record.expiresAt < new Date()) {
+      await this.db
+        .delete(passwordResetTokens)
+        .where(eq(passwordResetTokens.id, record.id));
+      throw new AppError(ERROR_CODES.INVALID_RESET_TOKEN, 'Reset token expired', 400);
+    }
+
+    const passwordHash = await hashPassword(newPassword);
+
+    await this.db
+      .update(users)
+      .set({ passwordHash, updatedAt: new Date() })
+      .where(eq(users.id, record.userId));
+
+    await this.db
+      .delete(passwordResetTokens)
+      .where(eq(passwordResetTokens.id, record.id));
+  }
+}
--- a/src/services/llm/llm.service.ts
+++ b/src/services/llm/llm.service.ts
@@ -0,0 +1,237 @@
+import { z } from 'zod';
+import { createHash } from 'node:crypto';
+import { env } from '../../config/env.js';
+import type { Stack, Level, QuestionType } from '../../db/schema/enums.js';
+
+export interface LlmConfig {
+  baseUrl: string;
+  model: string;
+  fallbackModel?: string;
+  apiKey?: string;
+  timeoutMs: number;
+  temperature: number;
+  maxTokens: number;
+  maxRetries: number;
+  retryDelayMs: number;
+}
+
+export interface ChatMessage {
+  role: 'system' | 'user' | 'assistant';
+  content: string;
+}
+
+export interface ChatCompletionResponse {
+  choices: Array<{
+    message?: { content: string };
+    text?: string;
+  }>;
+}
+
+const QUESTION_TYPES: QuestionType[] = ['single_choice', 'multiple_select', 'true_false', 'short_text'];
+
+const optionSchema = z.object({
+  key: z.string().min(1),
+  text: z.string().min(1),
+});
+
+const generatedQuestionSchema = z.object({
+  questionText: z.string().min(1),
+  type: z.enum(QUESTION_TYPES as [string, ...string[]]),
+  options: z.array(optionSchema).optional(),
+  correctAnswer: z.union([z.string(), z.array(z.string())]),
+  explanation: z.string().min(1),
+});
+
+const generateQuestionsResponseSchema = z.object({
+  questions: z.array(generatedQuestionSchema),
+});
+
+export type GeneratedQuestion = z.infer<typeof generatedQuestionSchema> & {
+  stack: Stack;
+  level: Level;
+};
+
+export interface GenerateQuestionsInput {
+  stack: Stack;
+  level: Level;
+  count: number;
+  types?: QuestionType[];
+}
+
+/** Metadata for persisting to question_cache_meta (used by QuestionService) */
+export interface LlmGenerationMeta {
+  llmModel: string;
+  promptHash: string;
+  generationTimeMs: number;
+  rawResponse: unknown;
+}
+
+export interface GenerateQuestionsResult {
+  questions: GeneratedQuestion[];
+  meta: LlmGenerationMeta;
+}
+
+export class LlmService {
+  private readonly config: LlmConfig;
+
+  constructor(config?: Partial<LlmConfig>) {
+    this.config = {
+      baseUrl: config?.baseUrl ?? env.LLM_BASE_URL,
+      model: config?.model ?? env.LLM_MODEL,
+      fallbackModel: config?.fallbackModel ?? env.LLM_FALLBACK_MODEL,
+      apiKey: config?.apiKey ?? env.LLM_API_KEY,
+      timeoutMs: config?.timeoutMs ?? env.LLM_TIMEOUT_MS,
+      temperature: config?.temperature ?? env.LLM_TEMPERATURE,
+      maxTokens: config?.maxTokens ?? env.LLM_MAX_TOKENS,
+      maxRetries: config?.maxRetries ?? env.LLM_MAX_RETRIES,
+      retryDelayMs: config?.retryDelayMs ?? env.LLM_RETRY_DELAY_MS,
+    };
+  }
+
+  async chat(messages: ChatMessage[]): Promise<string> {
+    const { content } = await this.chatWithMeta(messages);
+    return content;
+  }
+
+  /** Returns content and model used (for logging to question_cache_meta) */
+  async chatWithMeta(messages: ChatMessage[]): Promise<{ content: string; model: string }> {
+    let lastError: Error | null = null;
+
+    const modelsToTry = [this.config.model];
+    if (this.config.fallbackModel) {
+      modelsToTry.push(this.config.fallbackModel);
+    }
+
+    for (const model of modelsToTry) {
+      for (let attempt = 0; attempt <= this.config.maxRetries; attempt++) {
+        try {
+          const content = await this.executeChat(messages, model);
+          return { content, model };
+        } catch (err) {
+          lastError = err instanceof Error ? err : new Error('LLM request failed');
+          if (attempt < this.config.maxRetries) {
+            const delayMs = this.config.retryDelayMs * Math.pow(2, attempt);
+            await sleep(delayMs);
+          }
+        }
+      }
+    }
+
+    throw lastError ?? new Error('LLM request failed');
+  }
+
+  private async executeChat(messages: ChatMessage[], model: string): Promise<string> {
+    const url = `${this.config.baseUrl.replace(/\/$/, '')}/chat/completions`;
+
+    const headers: Record<string, string> = {
+      'Content-Type': 'application/json',
+    };
+    if (this.config.apiKey) {
+      headers['Authorization'] = `Bearer ${this.config.apiKey}`;
+    }
+
+    const body = {
+      model,
+      messages: messages.map((m) => ({ role: m.role, content: m.content })),
+      temperature: this.config.temperature,
+      max_tokens: this.config.maxTokens,
+    };
+
+    const controller = new AbortController();
+    const timeoutId = setTimeout(() => controller.abort(), this.config.timeoutMs);
+
+    try {
+      const res = await fetch(url, {
+        method: 'POST',
+        headers,
+        body: JSON.stringify(body),
+        signal: controller.signal,
+      });
+
+      clearTimeout(timeoutId);
+
+      if (!res.ok) {
+        const text = await res.text();
+        throw new Error(`LLM request failed: ${res.status} ${res.statusText} - ${text}`);
+      }
+
+      const data = (await res.json()) as ChatCompletionResponse;
+
+      const choice = data.choices?.[0];
+      const content = choice?.message?.content ?? choice?.text ?? '';
+
+      return content.trim();
+    } catch (err) {
+      clearTimeout(timeoutId);
+      if (err instanceof Error) {
+        throw err;
+      }
+      throw new Error('LLM request failed');
+    }
+  }
+
+  async generateQuestions(input: GenerateQuestionsInput): Promise<GenerateQuestionsResult> {
+    const { stack, level, count, types = QUESTION_TYPES } = input;
+
+    const typeList = types.join(', ');
+    const systemPrompt = `You are a technical interview question generator. Generate exactly ${count} programming/tech questions.
+Return ONLY valid JSON in this exact format (no markdown, no code blocks):
+{"questions":[{"questionText":"...","type":"single_choice|multiple_select|true_false|short_text","options":[{"key":"a","text":"..."}],"correctAnswer":"a" or ["a","b"],"explanation":"..."}]}
+Rules: type must be one of: ${typeList}. For single_choice/multiple_select: options array required with key (a,b,c,d). For true_false: options [{"key":"true","text":"True"},{"key":"false","text":"False"}]. For short_text: options omitted, correctAnswer is string.`;
+
+    const userPrompt = `Generate ${count} questions for stack="${stack}", level="${level}". Use types: ${typeList}.`;
+
+    const promptForHash = systemPrompt + '\n---\n' + userPrompt;
+    const promptHash = createHash('sha256').update(promptForHash).digest('hex');
+
+    const start = Date.now();
+    const { content: raw, model } = await this.chatWithMeta([
+      { role: 'system', content: systemPrompt },
+      { role: 'user', content: userPrompt },
+    ]);
+    const generationTimeMs = Date.now() - start;
+
+    const jsonStr = extractJson(raw);
+    const parsed = JSON.parse(jsonStr) as unknown;
+
+    const result = generateQuestionsResponseSchema.safeParse(parsed);
+    if (!result.success) {
+      throw new Error(`LLM response validation failed: ${result.error.message}`);
+    }
+
+    const questions: GeneratedQuestion[] = result.data.questions.map((q) => ({
+      ...q,
+      stack,
+      level,
+    }));
+
+    for (const q of questions) {
+      if ((q.type === 'single_choice' || q.type === 'multiple_select') && (!q.options || q.options.length === 0)) {
+        throw new Error(`Question validation failed: ${q.type} requires options`);
+      }
+      if (q.type === 'true_false' && (!q.options || q.options.length < 2)) {
+        throw new Error(`Question validation failed: true_false requires true/false options`);
+      }
+    }
+
+    return {
+      questions,
+      meta: {
+        llmModel: model,
+        promptHash,
+        generationTimeMs,
+        rawResponse: parsed,
+      },
+    };
+  }
+}
+
+function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+function extractJson(text: string): string {
+  const trimmed = text.trim();
+  const match = trimmed.match(/\{[\s\S]*\}/);
+  return match ? match[0]! : trimmed;
+}
--- a/src/services/user/user.service.ts
+++ b/src/services/user/user.service.ts
@@ -0,0 +1,175 @@
+import { eq } from 'drizzle-orm';
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres';
+import type * as schema from '../../db/schema/index.js';
+import { users, userStats } from '../../db/schema/index.js';
+import { notFound, conflict, ERROR_CODES } from '../../utils/errors.js';
+import type { User } from '../../db/schema/users.js';
+import type { SelfLevel } from '../../db/schema/index.js';
+
+type Db = NodePgDatabase<typeof schema>;
+
+export type UserStatItem = {
+  stack: string;
+  level: string;
+  totalQuestions: number;
+  correctAnswers: number;
+  testsTaken: number;
+  lastTestAt: string | null;
+};
+
+export type ProfileStats = {
+  byStack: UserStatItem[];
+  totalTestsTaken: number;
+  totalQuestions: number;
+  correctAnswers: number;
+  accuracy: number | null;
+};
+
+export type ProfileUpdateInput = {
+  nickname?: string;
+  avatarUrl?: string | null;
+  country?: string | null;
+  city?: string | null;
+  selfLevel?: SelfLevel | null;
+  isPublic?: boolean;
+};
+
+export type PublicProfile = {
+  id: string;
+  nickname: string;
+  avatarUrl: string | null;
+  country: string | null;
+  city: string | null;
+  selfLevel: string | null;
+  isPublic: boolean;
+  stats: ProfileStats;
+};
+
+export type PrivateProfile = PublicProfile & {
+  email: string;
+  emailVerifiedAt: string | null;
+  createdAt: string;
+  updatedAt: string;
+};
+
+async function getStatsForUser(db: Db, userId: string): Promise<ProfileStats> {
+  const rows = await db
+    .select()
+    .from(userStats)
+    .where(eq(userStats.userId, userId));
+
+  const byStack: UserStatItem[] = rows.map((r) => ({
+    stack: r.stack,
+    level: r.level,
+    totalQuestions: r.totalQuestions,
+    correctAnswers: r.correctAnswers,
+    testsTaken: r.testsTaken,
+    lastTestAt: r.lastTestAt?.toISOString() ?? null,
+  }));
+
+  const totalTestsTaken = rows.reduce((sum, r) => sum + r.testsTaken, 0);
+  const totalQuestions = rows.reduce((sum, r) => sum + r.totalQuestions, 0);
+  const correctAnswers = rows.reduce((sum, r) => sum + r.correctAnswers, 0);
+  const accuracy = totalQuestions > 0 ? correctAnswers / totalQuestions : null;
+
+  return { byStack, totalTestsTaken, totalQuestions, correctAnswers, accuracy };
+}
+
+function toPublicProfile(user: User, stats: ProfileStats): PublicProfile {
+  return {
+    id: user.id,
+    nickname: user.nickname,
+    avatarUrl: user.avatarUrl,
+    country: user.country,
+    city: user.city,
+    selfLevel: user.selfLevel,
+    isPublic: user.isPublic,
+    stats,
+  };
+}
+
+function toPrivateProfile(user: User, stats: ProfileStats): PrivateProfile {
+  return {
+    ...toPublicProfile(user, stats),
+    email: user.email,
+    emailVerifiedAt: user.emailVerifiedAt?.toISOString() ?? null,
+    createdAt: user.createdAt.toISOString(),
+    updatedAt: user.updatedAt.toISOString(),
+  };
+}
+
+export class UserService {
+  constructor(private readonly db: Db) {}
+
+  async getById(userId: string): Promise<User | null> {
+    const [user] = await this.db.select().from(users).where(eq(users.id, userId)).limit(1);
+    return user ?? null;
+  }
+
+  async getByNickname(nickname: string): Promise<User | null> {
+    const [user] = await this.db
+      .select()
+      .from(users)
+      .where(eq(users.nickname, nickname.trim()))
+      .limit(1);
+    return user ?? null;
+  }
+
+  async getPrivateProfile(userId: string): Promise<PrivateProfile> {
+    const [user, stats] = await Promise.all([this.getById(userId), getStatsForUser(this.db, userId)]);
+    if (!user) {
+      throw notFound('User not found');
+    }
+    return toPrivateProfile(user, stats);
+  }
+
+  async getPublicProfile(username: string): Promise<PublicProfile> {
+    const user = await this.getByNickname(username);
+    if (!user) {
+      throw notFound('User not found');
+    }
+    if (!user.isPublic) {
+      throw notFound('User not found');
+    }
+    const stats = await getStatsForUser(this.db, user.id);
+    return toPublicProfile(user, stats);
+  }
+
+  async updateProfile(userId: string, input: ProfileUpdateInput): Promise<PrivateProfile> {
+    const updateData: Partial<typeof users.$inferInsert> = {
+      updatedAt: new Date(),
+    };
+
+    if (input.nickname !== undefined) {
+      const trimmed = input.nickname.trim();
+      const [existing] = await this.db
+        .select({ id: users.id })
+        .from(users)
+        .where(eq(users.nickname, trimmed))
+        .limit(1);
+
+      if (existing && existing.id !== userId) {
+        throw conflict(ERROR_CODES.NICKNAME_TAKEN, 'Nickname already taken');
+      }
+      updateData.nickname = trimmed;
+    }
+    if (input.avatarUrl !== undefined) updateData.avatarUrl = input.avatarUrl;
+    if (input.country !== undefined) updateData.country = input.country;
+    if (input.city !== undefined) updateData.city = input.city;
+    if (input.selfLevel !== undefined) updateData.selfLevel = input.selfLevel;
+    if (input.isPublic !== undefined) updateData.isPublic = input.isPublic;
+
+    const [updated] = await this.db
+      .update(users)
+      .set(updateData)
+      .where(eq(users.id, userId))
+      .returning();
+
+    if (!updated) {
+      throw notFound('User not found');
+    }
+
+    const stats = await getStatsForUser(this.db, userId);
+    return toPrivateProfile(updated, stats);
+  }
+}
--- a/src/utils/errors.ts
+++ b/src/utils/errors.ts
@@ -0,0 +1,88 @@
+export const ERROR_CODES = {
+  BAD_REQUEST: 'BAD_REQUEST',
+  UNAUTHORIZED: 'UNAUTHORIZED',
+  FORBIDDEN: 'FORBIDDEN',
+  NOT_FOUND: 'NOT_FOUND',
+  CONFLICT: 'CONFLICT',
+  VALIDATION_ERROR: 'VALIDATION_ERROR',
+  RATE_LIMIT_EXCEEDED: 'RATE_LIMIT_EXCEEDED',
+  INTERNAL_ERROR: 'INTERNAL_ERROR',
+  INVALID_CREDENTIALS: 'INVALID_CREDENTIALS',
+  ACCOUNT_LOCKED: 'ACCOUNT_LOCKED',
+  EMAIL_TAKEN: 'EMAIL_TAKEN',
+  INVALID_REFRESH_TOKEN: 'INVALID_REFRESH_TOKEN',
+  TOKEN_REUSE_DETECTED: 'TOKEN_REUSE_DETECTED',
+  INVALID_CODE: 'INVALID_CODE',
+  ALREADY_VERIFIED: 'ALREADY_VERIFIED',
+  INVALID_RESET_TOKEN: 'INVALID_RESET_TOKEN',
+  NICKNAME_TAKEN: 'NICKNAME_TAKEN',
+  DAILY_LIMIT_REACHED: 'DAILY_LIMIT_REACHED',
+  EMAIL_NOT_VERIFIED: 'EMAIL_NOT_VERIFIED',
+  QUESTIONS_UNAVAILABLE: 'QUESTIONS_UNAVAILABLE',
+  QUESTION_ALREADY_ANSWERED: 'QUESTION_ALREADY_ANSWERED',
+  WRONG_QUESTION: 'WRONG_QUESTION',
+  TEST_ALREADY_FINISHED: 'TEST_ALREADY_FINISHED',
+  NO_ANSWERS: 'NO_ANSWERS',
+  TEST_NOT_FINISHED: 'TEST_NOT_FINISHED',
+  USER_NOT_FOUND: 'USER_NOT_FOUND',
+} as const;
+
+export type ErrorCode = (typeof ERROR_CODES)[keyof typeof ERROR_CODES];
+
+export class AppError extends Error {
+  constructor(
+    public readonly code: ErrorCode,
+    public readonly message: string,
+    public readonly statusCode: number = 500,
+    public readonly details?: unknown
+  ) {
+    super(message);
+    this.name = 'AppError';
+    Object.setPrototypeOf(this, AppError.prototype);
+  }
+
+  toJSON() {
+    const err: { code: string; message: string; details?: unknown } = {
+      code: this.code,
+      message: this.message,
+    };
+    if (this.details !== undefined) err.details = this.details;
+    return { error: err };
+  }
+}
+
+export function badRequest(message: string, details?: unknown): AppError {
+  return new AppError(ERROR_CODES.BAD_REQUEST, message, 400, details);
+}
+
+export function unauthorized(message: string): AppError {
+  return new AppError(ERROR_CODES.UNAUTHORIZED, message, 401);
+}
+
+export function forbidden(message: string): AppError {
+  return new AppError(ERROR_CODES.FORBIDDEN, message, 403);
+}
+
+export function notFound(message: string): AppError {
+  return new AppError(ERROR_CODES.NOT_FOUND, message, 404);
+}
+
+export function conflict(code: ErrorCode, message: string): AppError {
+  return new AppError(code, message, 409);
+}
+
+export function validationError(message: string, details?: unknown): AppError {
+  return new AppError(ERROR_CODES.VALIDATION_ERROR, message, 422, details);
+}
+
+export function rateLimitExceeded(message: string, retryAfter?: number): AppError {
+  const err = new AppError(ERROR_CODES.RATE_LIMIT_EXCEEDED, message, 429);
+  if (retryAfter !== undefined) {
+    (err as AppError & { retryAfter: number }).retryAfter = retryAfter;
+  }
+  return err;
+}
+
+export function internalError(message: string, cause?: unknown): AppError {
+  return new AppError(ERROR_CODES.INTERNAL_ERROR, message, 500, cause);
+}
--- a/src/utils/jwt.ts
+++ b/src/utils/jwt.ts
@@ -0,0 +1,52 @@
+import { createHash } from 'node:crypto';
+import * as jose from 'jose';
+import { env } from '../config/env.js';
+
+export function hashToken(token: string): string {
+  return createHash('sha256').update(token).digest('hex');
+}
+
+export interface AccessPayload {
+  sub: string;
+  email: string;
+  type: 'access';
+}
+
+export interface RefreshPayload {
+  sub: string;
+  sid: string;
+  type: 'refresh';
+}
+
+type JwtPayload = AccessPayload | RefreshPayload;
+
+const secret = new TextEncoder().encode(env.JWT_SECRET);
+
+export async function signAccessToken(payload: Omit<AccessPayload, 'type'>): Promise<string> {
+  return new jose.SignJWT({ ...payload, type: 'access' })
+    .setProtectedHeader({ alg: 'HS256' })
+    .setIssuedAt()
+    .setExpirationTime(env.JWT_ACCESS_TTL)
+    .sign(secret);
+}
+
+export async function signRefreshToken(payload: Omit<RefreshPayload, 'type'>): Promise<string> {
+  return new jose.SignJWT({ ...payload, type: 'refresh' })
+    .setProtectedHeader({ alg: 'HS256' })
+    .setIssuedAt()
+    .setExpirationTime(env.JWT_REFRESH_TTL)
+    .sign(secret);
+}
+
+export async function verifyToken(token: string): Promise<JwtPayload> {
+  const { payload } = await jose.jwtVerify(token, secret);
+  return payload as unknown as JwtPayload;
+}
+
+export function isAccessPayload(p: JwtPayload): p is AccessPayload {
+  return p.type === 'access';
+}
+
+export function isRefreshPayload(p: JwtPayload): p is RefreshPayload {
+  return p.type === 'refresh';
+}
--- a/src/utils/password.ts
+++ b/src/utils/password.ts
@@ -0,0 +1,15 @@
+import * as argon2 from 'argon2';
+
+const HASH_OPTIONS: argon2.Options = {
+  type: argon2.argon2id,
+  memoryCost: 19456,
+  timeCost: 2,
+};
+
+export async function hashPassword(plain: string): Promise<string> {
+  return argon2.hash(plain, HASH_OPTIONS);
+}
+
+export async function verifyPassword(hash: string, plain: string): Promise<boolean> {
+  return argon2.verify(hash, plain);
+}
--- a/src/utils/uuid.ts
+++ b/src/utils/uuid.ts
@@ -0,0 +1,37 @@
+import { randomBytes } from 'node:crypto';
+
+/**
+ * Generate UUID v7 (time-ordered, sortable).
+ * Simplified implementation: timestamp (48 bit) + random (74 bit).
+ */
+export function uuid7(): string {
+  const timestamp = Date.now();
+  const random = randomBytes(10);
+
+  const high = (timestamp / 0x100000000) >>> 0;
+  const low = timestamp >>> 0;
+
+  const b = new Uint8Array(16);
+  b[0] = (high >> 24) & 0xff;
+  b[1] = (high >> 16) & 0xff;
+  b[2] = (high >> 8) & 0xff;
+  b[3] = high & 0xff;
+  b[4] = (low >> 24) & 0xff;
+  b[5] = (low >> 16) & 0xff;
+  b[6] = ((low >> 8) & 0x3f) | 0x70;
+  b[7] = low & 0xff;
+  b[8] = 0x80 | (random[0] & 0x3f);
+  b[9] = random[1];
+  b[10] = random[2];
+  b[11] = random[3];
+  b[12] = random[4];
+  b[13] = random[5];
+  b[14] = random[6];
+  b[15] = random[7];
+
+  const hex = Array.from(b)
+    .map((x) => x.toString(16).padStart(2, '0'))
+    .join('');
+
+  return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
+}
Author	SHA1	Message	Date
Anton	50d6b34f11	feat: log LLM metadata to question_cache_meta Made-with: Cursor	2026-03-04 14:37:58 +03:00
Anton	189e9c127f	feat: add LLM retry and fallback Made-with: Cursor	2026-03-04 14:19:04 +03:00
Anton	e7c7bf363e	feat: register profile routes Made-with: Cursor	2026-03-04 14:18:23 +03:00
Anton	0564dc4b91	feat: add LLM question generation Made-with: Cursor	2026-03-04 14:18:22 +03:00
Anton	9da82c839f	feat: add stats to profile response Made-with: Cursor	2026-03-04 14:17:54 +03:00
Anton	6530e81402	feat: add profile routes Made-with: Cursor	2026-03-04 14:16:23 +03:00
Anton	b7573acbed	feat: add UserService Made-with: Cursor	2026-03-04 14:15:49 +03:00
Anton	bf544b3e5b	feat: add subscription middleware Made-with: Cursor	2026-03-04 14:15:09 +03:00
Anton	c5a4e26f33	feat: register auth routes in app Made-with: Cursor	2026-03-04 14:12:24 +03:00
Anton	682885ce5a	feat: add rate limiting to auth endpoints Made-with: Cursor	2026-03-04 14:11:29 +03:00
Anton	78809a064e	feat: add email verification and password reset Made-with: Cursor	2026-03-04 14:07:45 +03:00
Anton	e2baa14814	feat: add auth routes Made-with: Cursor	2026-03-04 14:07:03 +03:00
Anton	181be58a60	feat: add auth plugin Made-with: Cursor	2026-03-04 14:06:28 +03:00
Anton	8551d5f6d2	feat: add AuthService Made-with: Cursor	2026-03-04 14:05:34 +03:00
Anton	5cd13cd8ea	feat: add password hashing and JWT utils Made-with: Cursor	2026-03-04 14:04:24 +03:00
Anton	41b4f48a0f	chore: add initial migration and seed script Made-with: Cursor	2026-03-04 13:57:10 +03:00
Anton	c7c9982234	chore: wire schema and migrations Made-with: Cursor	2026-03-04 13:39:00 +03:00
Anton	ed8658916c	feat: add user_stats, audit_logs and verification tokens schema Made-with: Cursor	2026-03-04 13:38:46 +03:00
Anton	970a864823	feat: add question bank schema Made-with: Cursor	2026-03-04 13:38:31 +03:00
Anton	35873c3054	feat: add tests and test_questions schema Made-with: Cursor	2026-03-04 13:38:19 +03:00
Anton	8b3a4c475f	feat: add users and auth tables schema Made-with: Cursor	2026-03-04 13:38:07 +03:00
Anton	a7394c4d9d	feat: add Drizzle enums for schema Made-with: Cursor	2026-03-04 13:37:55 +03:00
Anton	53525dcd52	feat: add Redis plugin Made-with: Cursor	2026-03-04 13:36:35 +03:00
Anton	145301aba2	chore: add env config with validation Made-with: Cursor	2026-03-04 13:36:28 +03:00