refactor: introduce internal/domain/ layer, rename model.go → entity.go

Move all business-logic packages from internal/ root into internal/domain/:
  auth, cuisine, diary, dish, home, ingredient, language, menu, product,
  recipe, recognition, recommendation, savedrecipe, tag, units, user

Rename model.go → entity.go in packages that hold domain entities:
  diary, dish, home, ingredient, menu, product, recipe, savedrecipe, user

Update all import paths accordingly (adapters, infra/server, cmd/server,
tests). No logic changes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/internal/domain/user/calories.go

@@ -0,0 +1,71 @@
+package user
+
+import (
+	"math"
+	"time"
+)
+
+// Activity level multipliers (Mifflin-St Jeor).
+var activityMultiplier = map[string]float64{
+	"low":      1.375,
+	"moderate": 1.55,
+	"high":     1.725,
+}
+
+// Goal adjustments in kcal.
+var goalAdjustment = map[string]float64{
+	"lose":     -500,
+	"maintain": 0,
+	"gain":     300,
+}
+
+// AgeFromDOB computes age in years from a "YYYY-MM-DD" string. Returns nil on error.
+func AgeFromDOB(dob *string) *int {
+	if dob == nil {
+		return nil
+	}
+	t, err := time.Parse("2006-01-02", *dob)
+	if err != nil {
+		return nil
+	}
+	now := time.Now()
+	years := now.Year() - t.Year()
+	if now.Month() < t.Month() || (now.Month() == t.Month() && now.Day() < t.Day()) {
+		years--
+	}
+	return &years
+}
+
+// CalculateDailyCalories computes the daily calorie target using the
+// Mifflin-St Jeor equation. Returns nil if any required parameter is missing.
+func CalculateDailyCalories(heightCM *int, weightKG *float64, age *int, gender, activity, goal *string) *int {
+	if heightCM == nil || weightKG == nil || age == nil || gender == nil || activity == nil || goal == nil {
+		return nil
+	}
+
+	// BMR = 10 * weight(kg) + 6.25 * height(cm) - 5 * age
+	bmr := 10**weightKG + 6.25*float64(*heightCM) - 5*float64(*age)
+
+	switch *gender {
+	case "male":
+		bmr += 5
+	case "female":
+		bmr -= 161
+	default:
+		return nil
+	}
+
+	mult, ok := activityMultiplier[*activity]
+	if !ok {
+		return nil
+	}
+
+	adj, ok := goalAdjustment[*goal]
+	if !ok {
+		return nil
+	}
+
+	tdee := bmr * mult
+	result := int(math.Round(tdee + adj))
+	return &result
+}

backend/internal/domain/user/entity.go

@@ -0,0 +1,44 @@
+package user
+
+import (
+	"encoding/json"
+	"time"
+)
+
+type User struct {
+	ID            string          `json:"id"`
+	FirebaseUID   string          `json:"-"`
+	Email         string          `json:"email"`
+	Name          string          `json:"name"`
+	AvatarURL     *string         `json:"avatar_url"`
+	HeightCM      *int            `json:"height_cm"`
+	WeightKG      *float64        `json:"weight_kg"`
+	DateOfBirth   *string         `json:"date_of_birth"`
+	Gender        *string         `json:"gender"`
+	Activity      *string         `json:"activity"`
+	Goal          *string         `json:"goal"`
+	DailyCalories *int            `json:"daily_calories"`
+	Plan          string          `json:"plan"`
+	Preferences   json.RawMessage `json:"preferences"`
+	CreatedAt     time.Time       `json:"created_at"`
+	UpdatedAt     time.Time       `json:"updated_at"`
+}
+
+type UpdateProfileRequest struct {
+	Name          *string          `json:"name"`
+	HeightCM      *int             `json:"height_cm"`
+	WeightKG      *float64         `json:"weight_kg"`
+	DateOfBirth   *string          `json:"date_of_birth"`
+	Gender        *string          `json:"gender"`
+	Activity      *string          `json:"activity"`
+	Goal          *string          `json:"goal"`
+	Preferences   *json.RawMessage `json:"preferences"`
+	DailyCalories *int             `json:"-"` // internal, set by service
+}
+
+// HasBodyParams returns true if any body parameter is being updated
+// that would require recalculation of daily calories.
+func (r *UpdateProfileRequest) HasBodyParams() bool {
+	return r.HeightCM != nil || r.WeightKG != nil || r.DateOfBirth != nil ||
+		r.Gender != nil || r.Activity != nil || r.Goal != nil
+}

backend/internal/domain/user/handler.go

@@ -0,0 +1,78 @@
+package user
+
+import (
+	"encoding/json"
+	"log/slog"
+	"net/http"
+
+	"github.com/food-ai/backend/internal/infra/middleware"
+)
+
+const maxRequestBodySize = 1 << 20 // 1 MB
+
+type Handler struct {
+	service *Service
+}
+
+func NewHandler(service *Service) *Handler {
+	return &Handler{service: service}
+}
+
+func (h *Handler) Get(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.UserIDFromCtx(r.Context())
+	if userID == "" {
+		writeErrorJSON(w, http.StatusUnauthorized, "unauthorized")
+		return
+	}
+
+	u, err := h.service.GetProfile(r.Context(), userID)
+	if err != nil {
+		writeErrorJSON(w, http.StatusNotFound, "user not found")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, u)
+}
+
+func (h *Handler) Update(w http.ResponseWriter, r *http.Request) {
+	userID := middleware.UserIDFromCtx(r.Context())
+	if userID == "" {
+		writeErrorJSON(w, http.StatusUnauthorized, "unauthorized")
+		return
+	}
+
+	r.Body = http.MaxBytesReader(w, r.Body, maxRequestBodySize)
+	var req UpdateProfileRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeErrorJSON(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+
+	u, err := h.service.UpdateProfile(r.Context(), userID, req)
+	if err != nil {
+		writeErrorJSON(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusOK, u)
+}
+
+type errorResponse struct {
+	Error string `json:"error"`
+}
+
+func writeErrorJSON(w http.ResponseWriter, status int, msg string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	if err := json.NewEncoder(w).Encode(errorResponse{Error: msg}); err != nil {
+		slog.Error("failed to write error response", "err", err)
+	}
+}
+
+func writeJSON(w http.ResponseWriter, status int, v interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	if err := json.NewEncoder(w).Encode(v); err != nil {
+		slog.Error("failed to write JSON response", "err", err)
+	}
+}

backend/internal/domain/user/mocks/repository.go

@@ -0,0 +1,46 @@
+package mocks
+
+import (
+	"context"
+	"time"
+
+	"github.com/food-ai/backend/internal/domain/user"
+)
+
+type MockUserRepository struct {
+	UpsertByFirebaseUIDFn func(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error)
+	GetByIDFn             func(ctx context.Context, id string) (*user.User, error)
+	UpdateFn              func(ctx context.Context, id string, req user.UpdateProfileRequest) (*user.User, error)
+	UpdateInTxFn          func(ctx context.Context, id string, profileReq user.UpdateProfileRequest, caloriesReq *user.UpdateProfileRequest) (*user.User, error)
+	SetRefreshTokenFn     func(ctx context.Context, id, token string, expiresAt time.Time) error
+	FindByRefreshTokenFn  func(ctx context.Context, token string) (*user.User, error)
+	ClearRefreshTokenFn   func(ctx context.Context, id string) error
+}
+
+func (m *MockUserRepository) UpsertByFirebaseUID(ctx context.Context, uid, email, name, avatarURL string) (*user.User, error) {
+	return m.UpsertByFirebaseUIDFn(ctx, uid, email, name, avatarURL)
+}
+
+func (m *MockUserRepository) GetByID(ctx context.Context, id string) (*user.User, error) {
+	return m.GetByIDFn(ctx, id)
+}
+
+func (m *MockUserRepository) Update(ctx context.Context, id string, req user.UpdateProfileRequest) (*user.User, error) {
+	return m.UpdateFn(ctx, id, req)
+}
+
+func (m *MockUserRepository) UpdateInTx(ctx context.Context, id string, profileReq user.UpdateProfileRequest, caloriesReq *user.UpdateProfileRequest) (*user.User, error) {
+	return m.UpdateInTxFn(ctx, id, profileReq, caloriesReq)
+}
+
+func (m *MockUserRepository) SetRefreshToken(ctx context.Context, id, token string, expiresAt time.Time) error {
+	return m.SetRefreshTokenFn(ctx, id, token, expiresAt)
+}
+
+func (m *MockUserRepository) FindByRefreshToken(ctx context.Context, token string) (*user.User, error) {
+	return m.FindByRefreshTokenFn(ctx, token)
+}
+
+func (m *MockUserRepository) ClearRefreshToken(ctx context.Context, id string) error {
+	return m.ClearRefreshTokenFn(ctx, id)
+}

backend/internal/domain/user/repository.go

@@ -0,0 +1,223 @@
+package user
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// UserRepository defines the persistence interface for user data.
+type UserRepository interface {
+	UpsertByFirebaseUID(ctx context.Context, uid, email, name, avatarURL string) (*User, error)
+	GetByID(ctx context.Context, id string) (*User, error)
+	Update(ctx context.Context, id string, req UpdateProfileRequest) (*User, error)
+	UpdateInTx(ctx context.Context, id string, profileReq UpdateProfileRequest, caloriesReq *UpdateProfileRequest) (*User, error)
+	SetRefreshToken(ctx context.Context, id, token string, expiresAt time.Time) error
+	FindByRefreshToken(ctx context.Context, token string) (*User, error)
+	ClearRefreshToken(ctx context.Context, id string) error
+}
+
+type Repository struct {
+	pool *pgxpool.Pool
+}
+
+func NewRepository(pool *pgxpool.Pool) *Repository {
+	return &Repository{pool: pool}
+}
+
+func (r *Repository) UpsertByFirebaseUID(ctx context.Context, uid, email, name, avatarURL string) (*User, error) {
+	var avatarPtr *string
+	if avatarURL != "" {
+		avatarPtr = &avatarURL
+	}
+
+	query := `
+		INSERT INTO users (firebase_uid, email, name, avatar_url)
+		VALUES ($1, $2, $3, $4)
+		ON CONFLICT (firebase_uid) DO UPDATE SET
+			email = EXCLUDED.email,
+			name = CASE WHEN users.name = '' THEN EXCLUDED.name ELSE users.name END,
+			avatar_url = COALESCE(EXCLUDED.avatar_url, users.avatar_url),
+			updated_at = now()
+		RETURNING id, firebase_uid, email, name, avatar_url,
+			height_cm, weight_kg, date_of_birth, gender, activity, goal, daily_calories,
+			plan, preferences, created_at, updated_at`
+
+	return r.scanUser(r.pool.QueryRow(ctx, query, uid, email, name, avatarPtr))
+}
+
+func (r *Repository) GetByID(ctx context.Context, id string) (*User, error) {
+	query := `
+		SELECT id, firebase_uid, email, name, avatar_url,
+			height_cm, weight_kg, date_of_birth, gender, activity, goal, daily_calories,
+			plan, preferences, created_at, updated_at
+		FROM users WHERE id = $1`
+
+	return r.scanUser(r.pool.QueryRow(ctx, query, id))
+}
+
+func (r *Repository) Update(ctx context.Context, id string, req UpdateProfileRequest) (*User, error) {
+	query, args := buildUpdateQuery(id, req)
+	if query == "" {
+		return r.GetByID(ctx, id)
+	}
+	return r.scanUser(r.pool.QueryRow(ctx, query, args...))
+}
+
+// buildUpdateQuery constructs a dynamic UPDATE query from the request fields.
+// Returns empty string if there are no fields to update.
+func buildUpdateQuery(id string, req UpdateProfileRequest) (string, []interface{}) {
+	setClauses := []string{}
+	args := []interface{}{}
+	argIdx := 1
+
+	if req.Name != nil {
+		setClauses = append(setClauses, fmt.Sprintf("name = $%d", argIdx))
+		args = append(args, *req.Name)
+		argIdx++
+	}
+	if req.HeightCM != nil {
+		setClauses = append(setClauses, fmt.Sprintf("height_cm = $%d", argIdx))
+		args = append(args, *req.HeightCM)
+		argIdx++
+	}
+	if req.WeightKG != nil {
+		setClauses = append(setClauses, fmt.Sprintf("weight_kg = $%d", argIdx))
+		args = append(args, *req.WeightKG)
+		argIdx++
+	}
+	if req.DateOfBirth != nil {
+		setClauses = append(setClauses, fmt.Sprintf("date_of_birth = $%d", argIdx))
+		args = append(args, *req.DateOfBirth)
+		argIdx++
+	}
+	if req.Gender != nil {
+		setClauses = append(setClauses, fmt.Sprintf("gender = $%d", argIdx))
+		args = append(args, *req.Gender)
+		argIdx++
+	}
+	if req.Activity != nil {
+		setClauses = append(setClauses, fmt.Sprintf("activity = $%d", argIdx))
+		args = append(args, *req.Activity)
+		argIdx++
+	}
+	if req.Goal != nil {
+		setClauses = append(setClauses, fmt.Sprintf("goal = $%d", argIdx))
+		args = append(args, *req.Goal)
+		argIdx++
+	}
+	if req.Preferences != nil {
+		setClauses = append(setClauses, fmt.Sprintf("preferences = $%d", argIdx))
+		args = append(args, string(*req.Preferences))
+		argIdx++
+	}
+	if req.DailyCalories != nil {
+		setClauses = append(setClauses, fmt.Sprintf("daily_calories = $%d", argIdx))
+		args = append(args, *req.DailyCalories)
+		argIdx++
+	}
+
+	if len(setClauses) == 0 {
+		return "", nil
+	}
+
+	setClauses = append(setClauses, "updated_at = now()")
+
+	query := fmt.Sprintf(`
+		UPDATE users SET %s
+		WHERE id = $%d
+		RETURNING id, firebase_uid, email, name, avatar_url,
+			height_cm, weight_kg, date_of_birth, gender, activity, goal, daily_calories,
+			plan, preferences, created_at, updated_at`,
+		strings.Join(setClauses, ", "), argIdx)
+	args = append(args, id)
+
+	return query, args
+}
+
+func (r *Repository) UpdateInTx(ctx context.Context, id string, profileReq UpdateProfileRequest, caloriesReq *UpdateProfileRequest) (*User, error) {
+	tx, err := r.pool.BeginTx(ctx, pgx.TxOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("begin tx: %w", err)
+	}
+	defer tx.Rollback(ctx)
+
+	// First update: profile fields
+	query, args := buildUpdateQuery(id, profileReq)
+	if query == "" {
+		return nil, fmt.Errorf("no fields to update")
+	}
+	updated, err := r.scanUser(tx.QueryRow(ctx, query, args...))
+	if err != nil {
+		return nil, fmt.Errorf("update profile: %w", err)
+	}
+
+	// Second update: calories (if provided)
+	if caloriesReq != nil {
+		query, args = buildUpdateQuery(id, *caloriesReq)
+		if query != "" {
+			updated, err = r.scanUser(tx.QueryRow(ctx, query, args...))
+			if err != nil {
+				return nil, fmt.Errorf("update calories: %w", err)
+			}
+		}
+	}
+
+	if err := tx.Commit(ctx); err != nil {
+		return nil, fmt.Errorf("commit tx: %w", err)
+	}
+
+	return updated, nil
+}
+
+func (r *Repository) SetRefreshToken(ctx context.Context, id, token string, expiresAt time.Time) error {
+	query := `UPDATE users SET refresh_token = $2, token_expires_at = $3, updated_at = now() WHERE id = $1`
+	_, err := r.pool.Exec(ctx, query, id, token, expiresAt)
+	return err
+}
+
+func (r *Repository) FindByRefreshToken(ctx context.Context, token string) (*User, error) {
+	query := `
+		SELECT id, firebase_uid, email, name, avatar_url,
+			height_cm, weight_kg, date_of_birth, gender, activity, goal, daily_calories,
+			plan, preferences, created_at, updated_at
+		FROM users
+		WHERE refresh_token = $1 AND token_expires_at > now()`
+
+	return r.scanUser(r.pool.QueryRow(ctx, query, token))
+}
+
+func (r *Repository) ClearRefreshToken(ctx context.Context, id string) error {
+	query := `UPDATE users SET refresh_token = NULL, token_expires_at = NULL, updated_at = now() WHERE id = $1`
+	_, err := r.pool.Exec(ctx, query, id)
+	return err
+}
+
+type scannable interface {
+	Scan(dest ...interface{}) error
+}
+
+func (r *Repository) scanUser(row scannable) (*User, error) {
+	var u User
+	var prefs []byte
+	var dob *time.Time
+	err := row.Scan(
+		&u.ID, &u.FirebaseUID, &u.Email, &u.Name, &u.AvatarURL,
+		&u.HeightCM, &u.WeightKG, &dob, &u.Gender, &u.Activity, &u.Goal, &u.DailyCalories,
+		&u.Plan, &prefs, &u.CreatedAt, &u.UpdatedAt,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("scan user: %w", err)
+	}
+	if dob != nil {
+		s := dob.Format("2006-01-02")
+		u.DateOfBirth = &s
+	}
+	u.Preferences = json.RawMessage(prefs)
+	return &u, nil
+}

backend/internal/domain/user/service.go

@@ -0,0 +1,127 @@
+package user
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+type Service struct {
+	repo UserRepository
+}
+
+func NewService(repo UserRepository) *Service {
+	return &Service{repo: repo}
+}
+
+func (s *Service) GetProfile(ctx context.Context, userID string) (*User, error) {
+	return s.repo.GetByID(ctx, userID)
+}
+
+func (s *Service) UpdateProfile(ctx context.Context, userID string, req UpdateProfileRequest) (*User, error) {
+	if err := validateProfileRequest(req); err != nil {
+		return nil, err
+	}
+
+	if !req.HasBodyParams() {
+		updated, err := s.repo.Update(ctx, userID, req)
+		if err != nil {
+			return nil, fmt.Errorf("update profile: %w", err)
+		}
+		return updated, nil
+	}
+
+	// Need to update profile + recalculate calories in a single transaction.
+	// First, get current user to merge with incoming fields for calorie calculation.
+	current, err := s.repo.GetByID(ctx, userID)
+	if err != nil {
+		return nil, fmt.Errorf("get user: %w", err)
+	}
+
+	// Merge current values with request to compute calories
+	height := current.HeightCM
+	if req.HeightCM != nil {
+		height = req.HeightCM
+	}
+	weight := current.WeightKG
+	if req.WeightKG != nil {
+		weight = req.WeightKG
+	}
+	dob := current.DateOfBirth
+	if req.DateOfBirth != nil {
+		dob = req.DateOfBirth
+	}
+	age := AgeFromDOB(dob)
+	gender := current.Gender
+	if req.Gender != nil {
+		gender = req.Gender
+	}
+	activity := current.Activity
+	if req.Activity != nil {
+		activity = req.Activity
+	}
+	goal := current.Goal
+	if req.Goal != nil {
+		goal = req.Goal
+	}
+
+	calories := CalculateDailyCalories(height, weight, age, gender, activity, goal)
+
+	var calReq *UpdateProfileRequest
+	if calories != nil {
+		calReq = &UpdateProfileRequest{DailyCalories: calories}
+	}
+
+	updated, err := s.repo.UpdateInTx(ctx, userID, req, calReq)
+	if err != nil {
+		return nil, fmt.Errorf("update profile: %w", err)
+	}
+
+	return updated, nil
+}
+
+func validateProfileRequest(req UpdateProfileRequest) error {
+	if req.HeightCM != nil {
+		if *req.HeightCM < 100 || *req.HeightCM > 250 {
+			return fmt.Errorf("height_cm must be between 100 and 250")
+		}
+	}
+	if req.WeightKG != nil {
+		if *req.WeightKG < 30 || *req.WeightKG > 300 {
+			return fmt.Errorf("weight_kg must be between 30 and 300")
+		}
+	}
+	if req.DateOfBirth != nil {
+		t, err := time.Parse("2006-01-02", *req.DateOfBirth)
+		if err != nil {
+			return fmt.Errorf("date_of_birth must be in YYYY-MM-DD format")
+		}
+		if t.After(time.Now()) {
+			return fmt.Errorf("date_of_birth cannot be in the future")
+		}
+		age := AgeFromDOB(req.DateOfBirth)
+		if *age < 10 || *age > 120 {
+			return fmt.Errorf("date_of_birth must yield an age between 10 and 120")
+		}
+	}
+	if req.Gender != nil {
+		if *req.Gender != "male" && *req.Gender != "female" {
+			return fmt.Errorf("gender must be 'male' or 'female'")
+		}
+	}
+	if req.Activity != nil {
+		switch *req.Activity {
+		case "low", "moderate", "high":
+		default:
+			return fmt.Errorf("activity must be 'low', 'moderate', or 'high'")
+		}
+	}
+	if req.Goal != nil {
+		switch *req.Goal {
+		case "lose", "maintain", "gain":
+		default:
+			return fmt.Errorf("goal must be 'lose', 'maintain', or 'gain'")
+		}
+	}
+	return nil
+}