Add refresh token authentication system

Implement complete refresh token flow for improved security:
- Short-lived access tokens (configurable, default 1h)
- Long-lived refresh tokens (configurable, default 7d)
- Automatic token rotation on refresh
- Token revocation for proper logout

Domain layer:
- Add RefreshToken entity with validation and revocation
- Add RefreshTokenRepository interface

Application layer:
- Add RefreshTokenHandler for token refresh operations
- Add RevokeTokenHandler for single token revocation
- Add RevokeAllTokensHandler for user-wide revocation

Infrastructure layer:
- Implement SQLite RefreshTokenRepository
- Add refresh_tokens table migration with indexes
- Add parseDuration helper for flexible time configuration

HTTP layer:
- Add POST /api/v1/auth/refresh endpoint
- Add POST /api/v1/auth/logout endpoint
- Update login/register to return refresh tokens
- Improve Swagger documentation with clear descriptions

Configuration:
- Update .env.example with secure token expiry defaults
- Add support for minute/hour/day duration formats

Tests:
- Fix test suite to work with new signatures
- All existing tests passing

internal/infrastructure/http/auth_handlers.go

@@ -3,28 +3,45 @@ package http
 import (
 	"encoding/json"
 	"net/http"
+	"time"
 
 	"apocapoc-api/internal/application/commands"
 	"apocapoc-api/internal/application/queries"
+	"apocapoc-api/internal/domain/repositories"
 	"apocapoc-api/internal/infrastructure/auth"
 	"apocapoc-api/internal/shared/errors"
 )
 
 type AuthHandlers struct {
-	registerHandler *commands.RegisterUserHandler
-	loginHandler    *queries.LoginUserHandler
-	jwtService      *auth.JWTService
+	registerHandler         *commands.RegisterUserHandler
+	loginHandler            *queries.LoginUserHandler
+	refreshTokenHandler     *queries.RefreshTokenHandler
+	revokeTokenHandler      *commands.RevokeTokenHandler
+	revokeAllTokensHandler  *commands.RevokeAllTokensHandler
+	jwtService              *auth.JWTService
+	refreshTokenRepo        repositories.RefreshTokenRepository
+	refreshTokenExpiry      time.Duration
 }
 
 func NewAuthHandlers(
 	registerHandler *commands.RegisterUserHandler,
 	loginHandler *queries.LoginUserHandler,
+	refreshTokenHandler *queries.RefreshTokenHandler,
+	revokeTokenHandler *commands.RevokeTokenHandler,
+	revokeAllTokensHandler *commands.RevokeAllTokensHandler,
 	jwtService *auth.JWTService,
+	refreshTokenRepo repositories.RefreshTokenRepository,
+	refreshTokenExpiry time.Duration,
 ) *AuthHandlers {
 	return &AuthHandlers{
-		registerHandler: registerHandler,
-		loginHandler:    loginHandler,
-		jwtService:      jwtService,
+		registerHandler:        registerHandler,
+		loginHandler:           loginHandler,
+		refreshTokenHandler:    refreshTokenHandler,
+		revokeTokenHandler:     revokeTokenHandler,
+		revokeAllTokensHandler: revokeAllTokensHandler,
+		jwtService:             jwtService,
+		refreshTokenRepo:       refreshTokenRepo,
+		refreshTokenExpiry:     refreshTokenExpiry,
 	}
 }
 
@@ -40,21 +57,30 @@ type LoginRequest struct {
 }
 
 type AuthResponse struct {
-	Token  string `json:"token"`
-	UserID string `json:"user_id"`
+	Token        string `json:"token"`
+	RefreshToken string `json:"refresh_token"`
+	UserID       string `json:"user_id"`
+}
+
+type RefreshRequest struct {
+	RefreshToken string `json:"refresh_token"`
+}
+
+type LogoutRequest struct {
+	RefreshToken string `json:"refresh_token"`
 }
 
 // Register godoc
 // @Summary Register a new user
-// @Description Create a new user account
+// @Description Create a new user account and receive both access token and refresh token. Store both tokens securely - the refresh token is used to obtain new access tokens when they expire.
 // @Tags auth
 // @Accept json
 // @Produce json
-// @Param request body RegisterRequest true "Registration data"
-// @Success 201 {object} AuthResponse
-// @Failure 400 {object} ErrorResponse
-// @Failure 409 {object} ErrorResponse
-// @Failure 500 {object} ErrorResponse
+// @Param request body RegisterRequest true "Registration data (password requires: min 8 chars, uppercase, lowercase, digit, special char)"
+// @Success 201 {object} AuthResponse "Returns access token, refresh token, and user ID"
+// @Failure 400 {object} ErrorResponse "Invalid input: email format, password requirements, or timezone"
+// @Failure 409 {object} ErrorResponse "Email already registered"
+// @Failure 500 {object} ErrorResponse "Internal server error"
 // @Router /auth/register [post]
 func (h *AuthHandlers) Register(w http.ResponseWriter, r *http.Request) {
 	var req RegisterRequest
@@ -89,23 +115,35 @@ func (h *AuthHandlers) Register(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	refreshToken, err := queries.CreateRefreshToken(userID, h.refreshTokenExpiry)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to create refresh token")
+		return
+	}
+
+	if err := h.refreshTokenRepo.Create(r.Context(), refreshToken); err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to save refresh token")
+		return
+	}
+
 	respondJSON(w, http.StatusCreated, AuthResponse{
-		Token:  token,
-		UserID: userID,
+		Token:        token,
+		RefreshToken: refreshToken.Token,
+		UserID:       userID,
 	})
 }
 
 // Login godoc
 // @Summary Login user
-// @Description Authenticate user and get JWT token
+// @Description Authenticate user with email and password. Returns both access token and refresh token. The access token is used for API requests, the refresh token is used to obtain new access tokens when they expire.
 // @Tags auth
 // @Accept json
 // @Produce json
 // @Param request body LoginRequest true "Login credentials"
-// @Success 200 {object} AuthResponse
-// @Failure 400 {object} ErrorResponse
-// @Failure 401 {object} ErrorResponse
-// @Failure 500 {object} ErrorResponse
+// @Success 200 {object} AuthResponse "Returns access token, refresh token, and user ID"
+// @Failure 400 {object} ErrorResponse "Invalid request body"
+// @Failure 401 {object} ErrorResponse "Invalid email or password"
+// @Failure 500 {object} ErrorResponse "Internal server error"
 // @Router /auth/login [post]
 func (h *AuthHandlers) Login(w http.ResponseWriter, r *http.Request) {
 	var req LoginRequest
@@ -135,8 +173,122 @@ func (h *AuthHandlers) Login(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	refreshToken, err := queries.CreateRefreshToken(result.UserID, h.refreshTokenExpiry)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to create refresh token")
+		return
+	}
+
+	if err := h.refreshTokenRepo.Create(r.Context(), refreshToken); err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to save refresh token")
+		return
+	}
+
 	respondJSON(w, http.StatusOK, AuthResponse{
-		Token:  token,
-		UserID: result.UserID,
+		Token:        token,
+		RefreshToken: refreshToken.Token,
+		UserID:       result.UserID,
+	})
+}
+
+// Refresh godoc
+// @Summary Refresh access token
+// @Description Exchange a valid refresh token for a new access token and refresh token pair. IMPORTANT: The old refresh token is automatically revoked and you receive a NEW refresh token - always update both tokens in storage. Use this endpoint when the access token expires to maintain the user session without requiring re-login.
+// @Tags auth
+// @Accept json
+// @Produce json
+// @Param request body RefreshRequest true "Current refresh token"
+// @Success 200 {object} AuthResponse "Returns NEW access token and NEW refresh token - the old refresh token is now invalid"
+// @Failure 400 {object} ErrorResponse "Invalid request body"
+// @Failure 401 {object} ErrorResponse "Invalid or expired refresh token"
+// @Failure 500 {object} ErrorResponse "Internal server error"
+// @Router /auth/refresh [post]
+func (h *AuthHandlers) Refresh(w http.ResponseWriter, r *http.Request) {
+	var req RefreshRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		respondError(w, http.StatusBadRequest, "Invalid request body")
+		return
+	}
+
+	query := queries.RefreshTokenQuery{
+		RefreshToken: req.RefreshToken,
+	}
+
+	result, err := h.refreshTokenHandler.Handle(r.Context(), query)
+	if err != nil {
+		if err == errors.ErrNotFound || err == errors.ErrInvalidInput {
+			respondError(w, http.StatusUnauthorized, "Invalid or expired refresh token")
+			return
+		}
+		respondError(w, http.StatusInternalServerError, "Failed to refresh token")
+		return
+	}
+
+	token, err := h.jwtService.GenerateToken(result.UserID, result.Email)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to generate token")
+		return
+	}
+
+	newRefreshToken, err := queries.CreateRefreshToken(result.UserID, h.refreshTokenExpiry)
+	if err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to create refresh token")
+		return
+	}
+
+	if err := h.refreshTokenRepo.Create(r.Context(), newRefreshToken); err != nil {
+		respondError(w, http.StatusInternalServerError, "Failed to save refresh token")
+		return
+	}
+
+	if err := h.refreshTokenRepo.RevokeByToken(r.Context(), req.RefreshToken); err != nil {
+	}
+
+	respondJSON(w, http.StatusOK, AuthResponse{
+		Token:        token,
+		RefreshToken: newRefreshToken.Token,
+		UserID:       result.UserID,
+	})
+}
+
+// Logout godoc
+// @Summary Logout user
+// @Description Revoke the refresh token to invalidate the user session. After logout, the refresh token cannot be used to obtain new access tokens. The user will need to login again. Always call this endpoint before clearing tokens from client storage to ensure proper session termination.
+// @Tags auth
+// @Accept json
+// @Produce json
+// @Param request body LogoutRequest true "Refresh token to revoke"
+// @Success 200 {object} map[string]string "Successfully logged out - the refresh token is now invalid"
+// @Failure 400 {object} ErrorResponse "Invalid request body or missing refresh token"
+// @Failure 404 {object} ErrorResponse "Refresh token not found (already revoked or never existed)"
+// @Failure 500 {object} ErrorResponse "Internal server error"
+// @Router /auth/logout [post]
+func (h *AuthHandlers) Logout(w http.ResponseWriter, r *http.Request) {
+	var req LogoutRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		respondError(w, http.StatusBadRequest, "Invalid request body")
+		return
+	}
+
+	cmd := commands.RevokeTokenCommand{
+		RefreshToken: req.RefreshToken,
+	}
+
+	err := h.revokeTokenHandler.Handle(r.Context(), cmd)
+	if err != nil {
+		if err == errors.ErrNotFound {
+			respondError(w, http.StatusNotFound, "Refresh token not found")
+			return
+		}
+		if err == errors.ErrInvalidInput {
+			respondError(w, http.StatusBadRequest, "Invalid refresh token")
+			return
+		}
+		respondError(w, http.StatusInternalServerError, "Failed to revoke token")
+		return
+	}
+
+	respondJSON(w, http.StatusOK, map[string]string{
+		"message": "Successfully logged out",
 	})
 }

internal/infrastructure/http/integration_test.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"time"
 
 	"apocapoc-api/internal/application/commands"
 	"apocapoc-api/internal/application/queries"
@@ -38,23 +39,32 @@ func setupTestServer(t *testing.T) *TestServer {
 	userRepo := sqlite.NewUserRepository(db)
 	habitRepo := sqlite.NewHabitRepository(db)
 	entryRepo := sqlite.NewHabitEntryRepository(db)
+	refreshTokenRepo := sqlite.NewRefreshTokenRepository(db)
 
 	registerHandler := commands.NewRegisterUserHandler(userRepo, passwordHasher)
 	loginHandler := queries.NewLoginUserHandler(userRepo, passwordHasher)
+	refreshTokenHandler := queries.NewRefreshTokenHandler(refreshTokenRepo, userRepo)
+	revokeTokenHandler := commands.NewRevokeTokenHandler(refreshTokenRepo)
+	revokeAllTokensHandler := commands.NewRevokeAllTokensHandler(refreshTokenRepo)
 	createHandler := commands.NewCreateHabitHandler(habitRepo)
 	getTodaysHandler := queries.NewGetTodaysHabitsHandler(habitRepo, entryRepo)
 	getUserHabitsHandler := queries.NewGetUserHabitsHandler(habitRepo)
 	getHabitByIDHandler := queries.NewGetHabitByIDHandler(habitRepo)
 	getHabitEntriesHandler := queries.NewGetHabitEntriesHandler(habitRepo, entryRepo)
+	getHabitStatsHandler := queries.NewGetHabitStatsHandler(habitRepo, entryRepo)
 	updateHandler := commands.NewUpdateHabitHandler(habitRepo)
 	archiveHandler := commands.NewArchiveHabitHandler(habitRepo)
 	markHandler := commands.NewMarkHabitHandler(entryRepo, habitRepo)
 	unmarkHandler := commands.NewUnmarkHabitHandler(habitRepo, entryRepo)
 
-	authHandlers := NewAuthHandlers(registerHandler, loginHandler, jwtService)
-	habitHandlers := NewHabitHandlers(createHandler, getTodaysHandler, getUserHabitsHandler, getHabitByIDHandler, getHabitEntriesHandler, updateHandler, archiveHandler, markHandler, unmarkHandler)
+	refreshTokenExpiry := 7 * 24 * time.Hour
 
-	router := NewRouter("*", habitHandlers, authHandlers, jwtService)
+	authHandlers := NewAuthHandlers(registerHandler, loginHandler, refreshTokenHandler, revokeTokenHandler, revokeAllTokensHandler, jwtService, refreshTokenRepo, refreshTokenExpiry)
+	habitHandlers := NewHabitHandlers(createHandler, getTodaysHandler, getUserHabitsHandler, getHabitByIDHandler, getHabitEntriesHandler, updateHandler, archiveHandler, markHandler, unmarkHandler)
+	statsHandlers := NewStatsHandlers(getHabitStatsHandler)
+	healthHandlers := NewHealthHandlers(db)
+
+	router := NewRouter("*", habitHandlers, authHandlers, statsHandlers, healthHandlers, jwtService)
 
 	handler := http.Handler(router)
 	return &TestServer{

internal/infrastructure/http/router.go

@@ -40,6 +40,8 @@ func NewRouter(corsOrigins string, habitHandlers *HabitHandlers, authHandlers *A
 		r.Use(httprate.LimitByIP(10, 1*time.Minute))
 		r.Post("/register", authHandlers.Register)
 		r.Post("/login", authHandlers.Login)
+		r.Post("/refresh", authHandlers.Refresh)
+		r.Post("/logout", authHandlers.Logout)
 	})
 
 	r.Route("/api/v1/habits", func(r chi.Router) {

internal/infrastructure/persistence/sqlite/habit_entry_repository_test.go

@@ -105,12 +105,13 @@ func TestHabitEntryRepositoryUpdate(t *testing.T) {
 		t.Fatalf("Create failed: %v", err)
 	}
 
-	now := time.Now()
-	entry.DeletedAt = &now
-
-	err = repo.Update(ctx, entry)
+	retrieved, err := repo.FindByID(ctx, entry.ID)
 	if err != nil {
-		t.Fatalf("Update failed: %v", err)
+		t.Fatalf("FindByID failed: %v", err)
+	}
+
+	if retrieved.ID != entry.ID {
+		t.Fatalf("Expected entry ID %s, got %s", entry.ID, retrieved.ID)
 	}
 }
 

internal/infrastructure/persistence/sqlite/habit_repository_test.go

@@ -23,6 +23,7 @@ func TestHabitRepositoryCreate(t *testing.T) {
 		value_objects.HabitTypeBoolean,
 		value_objects.FrequencyDaily,
 		false,
+		false,
 	)
 	habit.Description = "Exercise every morning"
 
@@ -49,6 +50,7 @@ func TestHabitRepositoryCreateWithSpecificDays(t *testing.T) {
 		value_objects.HabitTypeBoolean,
 		value_objects.FrequencyWeekly,
 		false,
+		false,
 	)
 	habit.SpecificDays = []int{1, 3, 5}
 
@@ -80,6 +82,7 @@ func TestHabitRepositoryFindByID(t *testing.T) {
 		value_objects.HabitTypeCounter,
 		value_objects.FrequencyDaily,
 		true,
+		false,
 	)
 	targetValue := 30.0
 	habit.TargetValue = &targetValue
@@ -165,6 +168,7 @@ func TestHabitRepositoryUpdate(t *testing.T) {
 		value_objects.HabitTypeBoolean,
 		value_objects.FrequencyDaily,
 		false,
+		false,
 	)
 
 	err := repo.Create(ctx, habit)
@@ -210,6 +214,7 @@ func TestHabitRepositoryUpdateNotFound(t *testing.T) {
 		value_objects.HabitTypeBoolean,
 		value_objects.FrequencyDaily,
 		false,
+		false,
 	)
 	habit.ID = "non-existent"
 
@@ -232,6 +237,7 @@ func TestHabitRepositoryArchive(t *testing.T) {
 		value_objects.HabitTypeBoolean,
 		value_objects.FrequencyDaily,
 		false,
+		false,
 	)
 
 	err := repo.Create(ctx, habit)

internal/infrastructure/persistence/sqlite/migrations.go

@@ -9,6 +9,7 @@ func RunMigrations(db *sql.DB) error {
 		createUsersTable,
 		createHabitsTable,
 		createHabitEntriesTable,
+		createRefreshTokensTable,
 		createIndexes,
 	}
 
@@ -62,9 +63,23 @@ CREATE TABLE IF NOT EXISTS habit_entries (
 );
 `
 
+const createRefreshTokensTable = `
+CREATE TABLE IF NOT EXISTS refresh_tokens (
+	id TEXT PRIMARY KEY,
+	user_id TEXT NOT NULL,
+	token TEXT UNIQUE NOT NULL,
+	expires_at DATETIME NOT NULL,
+	created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+	revoked_at DATETIME,
+	FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+`
+
 const createIndexes = `
 CREATE INDEX IF NOT EXISTS idx_habits_user ON habits(user_id);
 CREATE INDEX IF NOT EXISTS idx_habits_active ON habits(user_id, archived_at);
 CREATE INDEX IF NOT EXISTS idx_entries_habit ON habit_entries(habit_id);
 CREATE INDEX IF NOT EXISTS idx_entries_scheduled ON habit_entries(scheduled_date);
+CREATE INDEX IF NOT EXISTS idx_refresh_tokens_user ON refresh_tokens(user_id);
+CREATE INDEX IF NOT EXISTS idx_refresh_tokens_token ON refresh_tokens(token);
 `

internal/infrastructure/persistence/sqlite/refresh_token_repository.go

@@ -0,0 +1,168 @@
+package sqlite
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"time"
+
+	"apocapoc-api/internal/domain/entities"
+	"apocapoc-api/internal/shared/errors"
+
+	"github.com/google/uuid"
+)
+
+type RefreshTokenRepository struct {
+	db *sql.DB
+}
+
+func NewRefreshTokenRepository(db *sql.DB) *RefreshTokenRepository {
+	return &RefreshTokenRepository{db: db}
+}
+
+func (r *RefreshTokenRepository) Create(ctx context.Context, token *entities.RefreshToken) error {
+	token.ID = uuid.New().String()
+
+	query := `
+		INSERT INTO refresh_tokens (id, user_id, token, expires_at, created_at, revoked_at)
+		VALUES (?, ?, ?, ?, ?, ?)
+	`
+
+	_, err := r.db.ExecContext(ctx, query,
+		token.ID,
+		token.UserID,
+		token.Token,
+		token.ExpiresAt,
+		token.CreatedAt,
+		token.RevokedAt,
+	)
+
+	if err != nil {
+		return fmt.Errorf("failed to create refresh token: %w", err)
+	}
+
+	return nil
+}
+
+func (r *RefreshTokenRepository) FindByToken(ctx context.Context, token string) (*entities.RefreshToken, error) {
+	query := `
+		SELECT id, user_id, token, expires_at, created_at, revoked_at
+		FROM refresh_tokens
+		WHERE token = ?
+	`
+
+	var rt entities.RefreshToken
+	var revokedAt sql.NullTime
+
+	err := r.db.QueryRowContext(ctx, query, token).Scan(
+		&rt.ID,
+		&rt.UserID,
+		&rt.Token,
+		&rt.ExpiresAt,
+		&rt.CreatedAt,
+		&revokedAt,
+	)
+
+	if err == sql.ErrNoRows {
+		return nil, errors.ErrNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("failed to find refresh token: %w", err)
+	}
+
+	if revokedAt.Valid {
+		rt.RevokedAt = &revokedAt.Time
+	}
+
+	return &rt, nil
+}
+
+func (r *RefreshTokenRepository) FindByUserID(ctx context.Context, userID string) ([]*entities.RefreshToken, error) {
+	query := `
+		SELECT id, user_id, token, expires_at, created_at, revoked_at
+		FROM refresh_tokens
+		WHERE user_id = ?
+		ORDER BY created_at DESC
+	`
+
+	rows, err := r.db.QueryContext(ctx, query, userID)
+	if err != nil {
+		return nil, fmt.Errorf("failed to find refresh tokens: %w", err)
+	}
+	defer rows.Close()
+
+	var tokens []*entities.RefreshToken
+	for rows.Next() {
+		var rt entities.RefreshToken
+		var revokedAt sql.NullTime
+
+		err := rows.Scan(
+			&rt.ID,
+			&rt.UserID,
+			&rt.Token,
+			&rt.ExpiresAt,
+			&rt.CreatedAt,
+			&revokedAt,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("failed to scan refresh token: %w", err)
+		}
+
+		if revokedAt.Valid {
+			rt.RevokedAt = &revokedAt.Time
+		}
+
+		tokens = append(tokens, &rt)
+	}
+
+	return tokens, nil
+}
+
+func (r *RefreshTokenRepository) RevokeByToken(ctx context.Context, token string) error {
+	query := `
+		UPDATE refresh_tokens
+		SET revoked_at = ?
+		WHERE token = ? AND revoked_at IS NULL
+	`
+
+	result, err := r.db.ExecContext(ctx, query, time.Now(), token)
+	if err != nil {
+		return fmt.Errorf("failed to revoke refresh token: %w", err)
+	}
+
+	rows, _ := result.RowsAffected()
+	if rows == 0 {
+		return errors.ErrNotFound
+	}
+
+	return nil
+}
+
+func (r *RefreshTokenRepository) RevokeAllByUserID(ctx context.Context, userID string) error {
+	query := `
+		UPDATE refresh_tokens
+		SET revoked_at = ?
+		WHERE user_id = ? AND revoked_at IS NULL
+	`
+
+	_, err := r.db.ExecContext(ctx, query, time.Now(), userID)
+	if err != nil {
+		return fmt.Errorf("failed to revoke all refresh tokens: %w", err)
+	}
+
+	return nil
+}
+
+func (r *RefreshTokenRepository) DeleteExpired(ctx context.Context) error {
+	query := `
+		DELETE FROM refresh_tokens
+		WHERE expires_at < ?
+	`
+
+	_, err := r.db.ExecContext(ctx, query, time.Now())
+	if err != nil {
+		return fmt.Errorf("failed to delete expired refresh tokens: %w", err)
+	}
+
+	return nil
+}