feat: add finance module (categories, transactions, summary, analytics)

- model/finance.go: FinanceCategory, FinanceTransaction, Summary, Analytics - repository/finance.go: CRUD + summary/analytics queries - service/finance.go: business logic with auto-seed default categories - handler/finance.go: REST endpoints with owner-only check (user_id=1) - db.go: finance_categories + finance_transactions migrations - main.go: register /finance/* routes Endpoints: GET/POST/PUT/DELETE /finance/categories, /finance/transactions GET /finance/summary, /finance/analytics
2026-03-01 04:22:10 +00:00
parent 8d9fe818f4
commit 23939ccc92
7 changed files with 970 additions and 1 deletions
--- a/internal/handler/finance.go
+++ b/internal/handler/finance.go
@@ -0,0 +1,266 @@
+package handler
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+
+	"github.com/daniil/homelab-api/internal/middleware"
+	"github.com/daniil/homelab-api/internal/model"
+	"github.com/daniil/homelab-api/internal/repository"
+	"github.com/daniil/homelab-api/internal/service"
+)
+
+const ownerUserID int64 = 1
+
+type FinanceHandler struct {
+	svc *service.FinanceService
+}
+
+func NewFinanceHandler(svc *service.FinanceService) *FinanceHandler {
+	return &FinanceHandler{svc: svc}
+}
+
+func (h *FinanceHandler) checkOwner(w http.ResponseWriter, r *http.Request) (int64, bool) {
+	userID := middleware.GetUserID(r.Context())
+	if userID != ownerUserID {
+		writeError(w, "forbidden", http.StatusForbidden)
+		return 0, false
+	}
+	return userID, true
+}
+
+// Categories
+
+func (h *FinanceHandler) ListCategories(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	cats, err := h.svc.ListCategories(userID)
+	if err != nil {
+		writeError(w, "failed to fetch categories", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, cats, http.StatusOK)
+}
+
+func (h *FinanceHandler) CreateCategory(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	var req model.CreateFinanceCategoryRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+	if req.Name == "" || req.Type == "" {
+		writeError(w, "name and type are required", http.StatusBadRequest)
+		return
+	}
+	if req.Type != "expense" && req.Type != "income" {
+		writeError(w, "type must be expense or income", http.StatusBadRequest)
+		return
+	}
+	cat, err := h.svc.CreateCategory(userID, &req)
+	if err != nil {
+		writeError(w, "failed to create category", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, cat, http.StatusCreated)
+}
+
+func (h *FinanceHandler) UpdateCategory(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+	if err != nil {
+		writeError(w, "invalid id", http.StatusBadRequest)
+		return
+	}
+	var req model.UpdateFinanceCategoryRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+	cat, err := h.svc.UpdateCategory(id, userID, &req)
+	if err != nil {
+		if errors.Is(err, repository.ErrFinanceCategoryNotFound) {
+			writeError(w, "category not found", http.StatusNotFound)
+			return
+		}
+		writeError(w, "failed to update category", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, cat, http.StatusOK)
+}
+
+func (h *FinanceHandler) DeleteCategory(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+	if err != nil {
+		writeError(w, "invalid id", http.StatusBadRequest)
+		return
+	}
+	if err := h.svc.DeleteCategory(id, userID); err != nil {
+		if errors.Is(err, repository.ErrFinanceCategoryNotFound) {
+			writeError(w, "category not found", http.StatusNotFound)
+			return
+		}
+		writeError(w, "failed to delete category", http.StatusInternalServerError)
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// Transactions
+
+func (h *FinanceHandler) ListTransactions(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	q := r.URL.Query()
+	month, _ := strconv.Atoi(q.Get("month"))
+	year, _ := strconv.Atoi(q.Get("year"))
+	var catID *int64
+	if c := q.Get("category_id"); c != "" {
+		v, _ := strconv.ParseInt(c, 10, 64)
+		catID = &v
+	}
+	txType := q.Get("type")
+	search := q.Get("search")
+	limit, _ := strconv.Atoi(q.Get("limit"))
+	offset, _ := strconv.Atoi(q.Get("offset"))
+
+	txs, err := h.svc.ListTransactions(userID, month, year, catID, txType, search, limit, offset)
+	if err != nil {
+		writeError(w, "failed to fetch transactions", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, txs, http.StatusOK)
+}
+
+func (h *FinanceHandler) CreateTransaction(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	var req model.CreateFinanceTransactionRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+	if req.Amount <= 0 {
+		writeError(w, "amount must be positive", http.StatusBadRequest)
+		return
+	}
+	if req.Type != "expense" && req.Type != "income" {
+		writeError(w, "type must be expense or income", http.StatusBadRequest)
+		return
+	}
+	tx, err := h.svc.CreateTransaction(userID, &req)
+	if err != nil {
+		writeError(w, "failed to create transaction", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, tx, http.StatusCreated)
+}
+
+func (h *FinanceHandler) UpdateTransaction(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+	if err != nil {
+		writeError(w, "invalid id", http.StatusBadRequest)
+		return
+	}
+	var req model.UpdateFinanceTransactionRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+	tx, err := h.svc.UpdateTransaction(id, userID, &req)
+	if err != nil {
+		if errors.Is(err, repository.ErrFinanceTransactionNotFound) {
+			writeError(w, "transaction not found", http.StatusNotFound)
+			return
+		}
+		writeError(w, "failed to update transaction", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, tx, http.StatusOK)
+}
+
+func (h *FinanceHandler) DeleteTransaction(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
+	if err != nil {
+		writeError(w, "invalid id", http.StatusBadRequest)
+		return
+	}
+	if err := h.svc.DeleteTransaction(id, userID); err != nil {
+		if errors.Is(err, repository.ErrFinanceTransactionNotFound) {
+			writeError(w, "transaction not found", http.StatusNotFound)
+			return
+		}
+		writeError(w, "failed to delete transaction", http.StatusInternalServerError)
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// Summary & Analytics
+
+func (h *FinanceHandler) Summary(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	q := r.URL.Query()
+	month, _ := strconv.Atoi(q.Get("month"))
+	year, _ := strconv.Atoi(q.Get("year"))
+	if month == 0 || year == 0 {
+		now := time.Now()
+		month = int(now.Month())
+		year = now.Year()
+	}
+	summary, err := h.svc.GetSummary(userID, month, year)
+	if err != nil {
+		writeError(w, "failed to get summary", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, summary, http.StatusOK)
+}
+
+func (h *FinanceHandler) Analytics(w http.ResponseWriter, r *http.Request) {
+	userID, ok := h.checkOwner(w, r)
+	if !ok {
+		return
+	}
+	months, _ := strconv.Atoi(r.URL.Query().Get("months"))
+	if months <= 0 {
+		months = 6
+	}
+	analytics, err := h.svc.GetAnalytics(userID, months)
+	if err != nil {
+		writeError(w, "failed to get analytics", http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, analytics, http.StatusOK)
+}
--- a/internal/model/finance.go
+++ b/internal/model/finance.go
@@ -0,0 +1,114 @@
+package model
+
+import (
+	"database/sql"
+	"time"
+)
+
+type FinanceCategory struct {
+	ID        int64          `db:"id" json:"id"`
+	UserID    int64          `db:"user_id" json:"user_id"`
+	Name      string         `db:"name" json:"name"`
+	Emoji     string         `db:"emoji" json:"emoji"`
+	Type      string         `db:"type" json:"type"`
+	Budget    sql.NullFloat64 `db:"budget" json:"-"`
+	BudgetVal *float64       `db:"-" json:"budget"`
+	Color     string         `db:"color" json:"color"`
+	SortOrder int            `db:"sort_order" json:"sort_order"`
+	CreatedAt time.Time      `db:"created_at" json:"created_at"`
+}
+
+func (c *FinanceCategory) ProcessForJSON() {
+	if c.Budget.Valid {
+		c.BudgetVal = &c.Budget.Float64
+	}
+}
+
+type FinanceTransaction struct {
+	ID           int64     `db:"id" json:"id"`
+	UserID       int64     `db:"user_id" json:"user_id"`
+	CategoryID   int64     `db:"category_id" json:"category_id"`
+	Type         string    `db:"type" json:"type"`
+	Amount       float64   `db:"amount" json:"amount"`
+	Description  string    `db:"description" json:"description"`
+	Date         time.Time `db:"date" json:"date"`
+	CreatedAt    time.Time `db:"created_at" json:"created_at"`
+	// Joined fields
+	CategoryName  string `db:"category_name" json:"category_name,omitempty"`
+	CategoryEmoji string `db:"category_emoji" json:"category_emoji,omitempty"`
+}
+
+type CreateFinanceCategoryRequest struct {
+	Name      string   `json:"name"`
+	Emoji     string   `json:"emoji,omitempty"`
+	Type      string   `json:"type"`
+	Budget    *float64 `json:"budget,omitempty"`
+	Color     string   `json:"color,omitempty"`
+	SortOrder int      `json:"sort_order,omitempty"`
+}
+
+type UpdateFinanceCategoryRequest struct {
+	Name      *string  `json:"name,omitempty"`
+	Emoji     *string  `json:"emoji,omitempty"`
+	Type      *string  `json:"type,omitempty"`
+	Budget    *float64 `json:"budget,omitempty"`
+	Color     *string  `json:"color,omitempty"`
+	SortOrder *int     `json:"sort_order,omitempty"`
+}
+
+type CreateFinanceTransactionRequest struct {
+	CategoryID  int64   `json:"category_id"`
+	Type        string  `json:"type"`
+	Amount      float64 `json:"amount"`
+	Description string  `json:"description,omitempty"`
+	Date        string  `json:"date"`
+}
+
+type UpdateFinanceTransactionRequest struct {
+	CategoryID  *int64   `json:"category_id,omitempty"`
+	Type        *string  `json:"type,omitempty"`
+	Amount      *float64 `json:"amount,omitempty"`
+	Description *string  `json:"description,omitempty"`
+	Date        *string  `json:"date,omitempty"`
+}
+
+type FinanceSummary struct {
+	Balance      float64              `json:"balance"`
+	TotalIncome  float64              `json:"total_income"`
+	TotalExpense float64              `json:"total_expense"`
+	ByCategory   []CategorySummary    `json:"by_category"`
+	Daily        []DailySummary       `json:"daily"`
+}
+
+type CategorySummary struct {
+	CategoryID   int64   `json:"category_id" db:"category_id"`
+	CategoryName string  `json:"category_name" db:"category_name"`
+	CategoryEmoji string `json:"category_emoji" db:"category_emoji"`
+	Type         string  `json:"type" db:"type"`
+	Amount       float64 `json:"amount" db:"amount"`
+	Percentage   float64 `json:"percentage"`
+	Budget       *float64 `json:"budget,omitempty"`
+}
+
+type DailySummary struct {
+	Date   string  `json:"date" db:"date"`
+	Amount float64 `json:"amount" db:"amount"`
+}
+
+type FinanceAnalytics struct {
+	MonthlyTrend       []MonthlyTrend  `json:"monthly_trend"`
+	AvgDailyExpense    float64         `json:"avg_daily_expense"`
+	ComparisonPrevMonth Comparison     `json:"comparison_prev_month"`
+}
+
+type MonthlyTrend struct {
+	Month   string  `json:"month" db:"month"`
+	Income  float64 `json:"income" db:"income"`
+	Expense float64 `json:"expense" db:"expense"`
+}
+
+type Comparison struct {
+	Current     float64 `json:"current"`
+	Previous    float64 `json:"previous"`
+	DiffPercent float64 `json:"diff_percent"`
+}
--- a/internal/repository/db.go
+++ b/internal/repository/db.go
@@ -127,3 +127,40 @@ func RunMigrations(db *sqlx.DB) error {

 	return nil
 }
+
+func RunFinanceMigrations(db *sqlx.DB) error {
+	migrations := []string{
+		`CREATE TABLE IF NOT EXISTS finance_categories (
+			id SERIAL PRIMARY KEY,
+			user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
+			name VARCHAR(100) NOT NULL,
+			emoji VARCHAR(10) DEFAULT '',
+			type VARCHAR(10) NOT NULL,
+			budget DECIMAL(12,2),
+			color VARCHAR(7) DEFAULT '#6366f1',
+			sort_order INTEGER DEFAULT 0,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		)`,
+		`CREATE TABLE IF NOT EXISTS finance_transactions (
+			id SERIAL PRIMARY KEY,
+			user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
+			category_id INTEGER REFERENCES finance_categories(id) ON DELETE SET NULL,
+			type VARCHAR(10) NOT NULL,
+			amount DECIMAL(12,2) NOT NULL,
+			description TEXT DEFAULT '',
+			date DATE NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_finance_categories_user ON finance_categories(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_finance_transactions_user ON finance_transactions(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_finance_transactions_date ON finance_transactions(date)`,
+		`CREATE INDEX IF NOT EXISTS idx_finance_transactions_category ON finance_transactions(category_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_finance_transactions_user_date ON finance_transactions(user_id, date)`,
+	}
+	for _, m := range migrations {
+		if _, err := db.Exec(m); err != nil {
+			return err
+		}
+	}
+	return nil
+}
--- a/internal/repository/finance.go
+++ b/internal/repository/finance.go
@@ -0,0 +1,363 @@
+package repository
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/daniil/homelab-api/internal/model"
+	"github.com/jmoiron/sqlx"
+)
+
+var ErrFinanceCategoryNotFound = errors.New("finance category not found")
+var ErrFinanceTransactionNotFound = errors.New("finance transaction not found")
+
+type FinanceRepository struct {
+	db *sqlx.DB
+}
+
+func NewFinanceRepository(db *sqlx.DB) *FinanceRepository {
+	return &FinanceRepository{db: db}
+}
+
+// --- Categories ---
+
+func (r *FinanceRepository) CreateCategory(cat *model.FinanceCategory) error {
+	query := `INSERT INTO finance_categories (user_id, name, emoji, type, budget, color, sort_order)
+		VALUES ($1, $2, $3, $4, $5, $6, $7) RETURNING id, created_at`
+	return r.db.QueryRow(query, cat.UserID, cat.Name, cat.Emoji, cat.Type, cat.Budget, cat.Color, cat.SortOrder).
+		Scan(&cat.ID, &cat.CreatedAt)
+}
+
+func (r *FinanceRepository) ListCategories(userID int64) ([]model.FinanceCategory, error) {
+	query := `SELECT id, user_id, name, emoji, type, budget, color, sort_order, created_at
+		FROM finance_categories WHERE user_id = $1 ORDER BY sort_order, id`
+	rows, err := r.db.Query(query, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var cats []model.FinanceCategory
+	for rows.Next() {
+		var c model.FinanceCategory
+		if err := rows.Scan(&c.ID, &c.UserID, &c.Name, &c.Emoji, &c.Type, &c.Budget, &c.Color, &c.SortOrder, &c.CreatedAt); err != nil {
+			return nil, err
+		}
+		c.ProcessForJSON()
+		cats = append(cats, c)
+	}
+	return cats, nil
+}
+
+func (r *FinanceRepository) GetCategory(id, userID int64) (*model.FinanceCategory, error) {
+	var c model.FinanceCategory
+	query := `SELECT id, user_id, name, emoji, type, budget, color, sort_order, created_at
+		FROM finance_categories WHERE id = $1 AND user_id = $2`
+	err := r.db.QueryRow(query, id, userID).Scan(&c.ID, &c.UserID, &c.Name, &c.Emoji, &c.Type, &c.Budget, &c.Color, &c.SortOrder, &c.CreatedAt)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrFinanceCategoryNotFound
+		}
+		return nil, err
+	}
+	c.ProcessForJSON()
+	return &c, nil
+}
+
+func (r *FinanceRepository) UpdateCategory(cat *model.FinanceCategory) error {
+	query := `UPDATE finance_categories SET name=$2, emoji=$3, type=$4, budget=$5, color=$6, sort_order=$7
+		WHERE id=$1 AND user_id=$8`
+	result, err := r.db.Exec(query, cat.ID, cat.Name, cat.Emoji, cat.Type, cat.Budget, cat.Color, cat.SortOrder, cat.UserID)
+	if err != nil {
+		return err
+	}
+	rows, _ := result.RowsAffected()
+	if rows == 0 {
+		return ErrFinanceCategoryNotFound
+	}
+	return nil
+}
+
+func (r *FinanceRepository) DeleteCategory(id, userID int64) error {
+	result, err := r.db.Exec(`DELETE FROM finance_categories WHERE id=$1 AND user_id=$2`, id, userID)
+	if err != nil {
+		return err
+	}
+	rows, _ := result.RowsAffected()
+	if rows == 0 {
+		return ErrFinanceCategoryNotFound
+	}
+	return nil
+}
+
+func (r *FinanceRepository) SeedDefaultCategories(userID int64) error {
+	type cat struct {
+		emoji, name, typ, color string
+	}
+	defaults := []cat{
+		{"🏠", "Жильё", "expense", "#ef4444"},
+		{"🍔", "Еда", "expense", "#f97316"},
+		{"🚗", "Транспорт", "expense", "#6366f1"},
+		{"👕", "Одежда", "expense", "#8b5cf6"},
+		{"🏥", "Здоровье", "expense", "#22c55e"},
+		{"🎮", "Развлечения", "expense", "#ec4899"},
+		{"📱", "Связь / Подписки", "expense", "#0ea5e9"},
+		{"✈️", "Путешествия", "expense", "#14b8a6"},
+		{"🎁", "Подарки", "expense", "#a855f7"},
+		{"🛒", "Бытовое", "expense", "#64748b"},
+		{"🛍️", "Маркетплейсы", "expense", "#F7B538"},
+		{"💎", "Накопления", "expense", "#0D4F4F"},
+		{"📦", "Другое", "expense", "#78716c"},
+		{"💰", "Зарплата", "income", "#22c55e"},
+		{"💼", "Фриланс", "income", "#6366f1"},
+		{"📈", "Другой доход", "income", "#0ea5e9"},
+	}
+	for i, c := range defaults {
+		_, err := r.db.Exec(`INSERT INTO finance_categories (user_id, name, emoji, type, color, sort_order) VALUES ($1,$2,$3,$4,$5,$6)`,
+			userID, c.name, c.emoji, c.typ, c.color, i)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// --- Transactions ---
+
+func (r *FinanceRepository) CreateTransaction(tx *model.FinanceTransaction) error {
+	query := `INSERT INTO finance_transactions (user_id, category_id, type, amount, description, date)
+		VALUES ($1,$2,$3,$4,$5,$6) RETURNING id, created_at`
+	return r.db.QueryRow(query, tx.UserID, tx.CategoryID, tx.Type, tx.Amount, tx.Description, tx.Date).
+		Scan(&tx.ID, &tx.CreatedAt)
+}
+
+func (r *FinanceRepository) ListTransactions(userID int64, month, year int, categoryID *int64, txType, search string, limit, offset int) ([]model.FinanceTransaction, error) {
+	args := []interface{}{userID}
+	conditions := []string{"t.user_id = $1"}
+	argIdx := 2
+
+	if month > 0 && year > 0 {
+		conditions = append(conditions, fmt.Sprintf("EXTRACT(MONTH FROM t.date) = $%d AND EXTRACT(YEAR FROM t.date) = $%d", argIdx, argIdx+1))
+		args = append(args, month, year)
+		argIdx += 2
+	}
+	if categoryID != nil {
+		conditions = append(conditions, fmt.Sprintf("t.category_id = $%d", argIdx))
+		args = append(args, *categoryID)
+		argIdx++
+	}
+	if txType != "" {
+		conditions = append(conditions, fmt.Sprintf("t.type = $%d", argIdx))
+		args = append(args, txType)
+		argIdx++
+	}
+	if search != "" {
+		conditions = append(conditions, fmt.Sprintf("t.description ILIKE $%d", argIdx))
+		args = append(args, "%"+search+"%")
+		argIdx++
+	}
+
+	if limit <= 0 {
+		limit = 50
+	}
+
+	query := fmt.Sprintf(`SELECT t.id, t.user_id, t.category_id, t.type, t.amount, t.description, t.date, t.created_at,
+		COALESCE(c.name,'') as category_name, COALESCE(c.emoji,'') as category_emoji
+		FROM finance_transactions t
+		LEFT JOIN finance_categories c ON c.id = t.category_id
+		WHERE %s ORDER BY t.date DESC, t.id DESC LIMIT %d OFFSET %d`,
+		strings.Join(conditions, " AND "), limit, offset)
+
+	rows, err := r.db.Query(query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var txs []model.FinanceTransaction
+	for rows.Next() {
+		var t model.FinanceTransaction
+		if err := rows.Scan(&t.ID, &t.UserID, &t.CategoryID, &t.Type, &t.Amount, &t.Description, &t.Date, &t.CreatedAt,
+			&t.CategoryName, &t.CategoryEmoji); err != nil {
+			return nil, err
+		}
+		txs = append(txs, t)
+	}
+	return txs, nil
+}
+
+func (r *FinanceRepository) GetTransaction(id, userID int64) (*model.FinanceTransaction, error) {
+	var t model.FinanceTransaction
+	query := `SELECT t.id, t.user_id, t.category_id, t.type, t.amount, t.description, t.date, t.created_at,
+		COALESCE(c.name,'') as category_name, COALESCE(c.emoji,'') as category_emoji
+		FROM finance_transactions t LEFT JOIN finance_categories c ON c.id = t.category_id
+		WHERE t.id=$1 AND t.user_id=$2`
+	err := r.db.QueryRow(query, id, userID).Scan(&t.ID, &t.UserID, &t.CategoryID, &t.Type, &t.Amount, &t.Description, &t.Date, &t.CreatedAt,
+		&t.CategoryName, &t.CategoryEmoji)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, ErrFinanceTransactionNotFound
+		}
+		return nil, err
+	}
+	return &t, nil
+}
+
+func (r *FinanceRepository) UpdateTransaction(tx *model.FinanceTransaction) error {
+	query := `UPDATE finance_transactions SET category_id=$2, type=$3, amount=$4, description=$5, date=$6
+		WHERE id=$1 AND user_id=$7`
+	result, err := r.db.Exec(query, tx.ID, tx.CategoryID, tx.Type, tx.Amount, tx.Description, tx.Date, tx.UserID)
+	if err != nil {
+		return err
+	}
+	rows, _ := result.RowsAffected()
+	if rows == 0 {
+		return ErrFinanceTransactionNotFound
+	}
+	return nil
+}
+
+func (r *FinanceRepository) DeleteTransaction(id, userID int64) error {
+	result, err := r.db.Exec(`DELETE FROM finance_transactions WHERE id=$1 AND user_id=$2`, id, userID)
+	if err != nil {
+		return err
+	}
+	rows, _ := result.RowsAffected()
+	if rows == 0 {
+		return ErrFinanceTransactionNotFound
+	}
+	return nil
+}
+
+// --- Summary & Analytics ---
+
+func (r *FinanceRepository) GetSummary(userID int64, month, year int) (*model.FinanceSummary, error) {
+	summary := &model.FinanceSummary{}
+
+	// Total income & expense for the month
+	err := r.db.QueryRow(`SELECT COALESCE(SUM(CASE WHEN type='income' THEN amount ELSE 0 END),0),
+		COALESCE(SUM(CASE WHEN type='expense' THEN amount ELSE 0 END),0)
+		FROM finance_transactions WHERE user_id=$1 AND EXTRACT(MONTH FROM date)=$2 AND EXTRACT(YEAR FROM date)=$3`,
+		userID, month, year).Scan(&summary.TotalIncome, &summary.TotalExpense)
+	if err != nil {
+		return nil, err
+	}
+	summary.Balance = summary.TotalIncome - summary.TotalExpense
+
+	// By category
+	rows, err := r.db.Query(`SELECT c.id, c.name, c.emoji, t.type, SUM(t.amount) as amount
+		FROM finance_transactions t JOIN finance_categories c ON c.id=t.category_id
+		WHERE t.user_id=$1 AND EXTRACT(MONTH FROM t.date)=$2 AND EXTRACT(YEAR FROM t.date)=$3
+		GROUP BY c.id, c.name, c.emoji, t.type ORDER BY amount DESC`, userID, month, year)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var cs model.CategorySummary
+		if err := rows.Scan(&cs.CategoryID, &cs.CategoryName, &cs.CategoryEmoji, &cs.Type, &cs.Amount); err != nil {
+			return nil, err
+		}
+		total := summary.TotalExpense
+		if cs.Type == "income" {
+			total = summary.TotalIncome
+		}
+		if total > 0 {
+			cs.Percentage = cs.Amount / total * 100
+		}
+		summary.ByCategory = append(summary.ByCategory, cs)
+	}
+	if summary.ByCategory == nil {
+		summary.ByCategory = []model.CategorySummary{}
+	}
+
+	// Daily expenses
+	dailyRows, err := r.db.Query(`SELECT date::text, SUM(amount) as amount
+		FROM finance_transactions WHERE user_id=$1 AND type='expense' AND EXTRACT(MONTH FROM date)=$2 AND EXTRACT(YEAR FROM date)=$3
+		GROUP BY date ORDER BY date`, userID, month, year)
+	if err != nil {
+		return nil, err
+	}
+	defer dailyRows.Close()
+
+	for dailyRows.Next() {
+		var d model.DailySummary
+		if err := dailyRows.Scan(&d.Date, &d.Amount); err != nil {
+			return nil, err
+		}
+		summary.Daily = append(summary.Daily, d)
+	}
+	if summary.Daily == nil {
+		summary.Daily = []model.DailySummary{}
+	}
+
+	return summary, nil
+}
+
+func (r *FinanceRepository) GetAnalytics(userID int64, months int) (*model.FinanceAnalytics, error) {
+	analytics := &model.FinanceAnalytics{}
+
+	// Monthly trend
+	rows, err := r.db.Query(`SELECT TO_CHAR(date, 'YYYY-MM') as month,
+		COALESCE(SUM(CASE WHEN type='income' THEN amount ELSE 0 END),0) as income,
+		COALESCE(SUM(CASE WHEN type='expense' THEN amount ELSE 0 END),0) as expense
+		FROM finance_transactions WHERE user_id=$1 AND date >= (CURRENT_DATE - ($2 || ' months')::interval)
+		GROUP BY TO_CHAR(date, 'YYYY-MM') ORDER BY month`, userID, months)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		var mt model.MonthlyTrend
+		if err := rows.Scan(&mt.Month, &mt.Income, &mt.Expense); err != nil {
+			return nil, err
+		}
+		analytics.MonthlyTrend = append(analytics.MonthlyTrend, mt)
+	}
+	if analytics.MonthlyTrend == nil {
+		analytics.MonthlyTrend = []model.MonthlyTrend{}
+	}
+
+	// Avg daily expense for current month
+	now := time.Now()
+	var totalExpense float64
+	var dayCount int
+	r.db.QueryRow(`SELECT COALESCE(SUM(amount),0), COUNT(DISTINCT date)
+		FROM finance_transactions WHERE user_id=$1 AND type='expense'
+		AND EXTRACT(MONTH FROM date)=$2 AND EXTRACT(YEAR FROM date)=$3`,
+		userID, int(now.Month()), now.Year()).Scan(&totalExpense, &dayCount)
+	if dayCount > 0 {
+		analytics.AvgDailyExpense = totalExpense / float64(dayCount)
+	}
+
+	// Comparison with previous month
+	prevMonth := now.AddDate(0, -1, 0)
+	var currentMonthExp, prevMonthExp float64
+	r.db.QueryRow(`SELECT COALESCE(SUM(amount),0) FROM finance_transactions WHERE user_id=$1 AND type='expense'
+		AND EXTRACT(MONTH FROM date)=$2 AND EXTRACT(YEAR FROM date)=$3`,
+		userID, int(now.Month()), now.Year()).Scan(&currentMonthExp)
+	r.db.QueryRow(`SELECT COALESCE(SUM(amount),0) FROM finance_transactions WHERE user_id=$1 AND type='expense'
+		AND EXTRACT(MONTH FROM date)=$2 AND EXTRACT(YEAR FROM date)=$3`,
+		userID, int(prevMonth.Month()), prevMonth.Year()).Scan(&prevMonthExp)
+
+	analytics.ComparisonPrevMonth = model.Comparison{
+		Current:  currentMonthExp,
+		Previous: prevMonthExp,
+	}
+	if prevMonthExp > 0 {
+		analytics.ComparisonPrevMonth.DiffPercent = (currentMonthExp - prevMonthExp) / prevMonthExp * 100
+	}
+
+	return analytics, nil
+}
+
+func (r *FinanceRepository) HasCategories(userID int64) (bool, error) {
+	var count int
+	err := r.db.Get(&count, `SELECT COUNT(*) FROM finance_categories WHERE user_id=$1`, userID)
+	return count > 0, err
+}
--- a/internal/service/finance.go
+++ b/internal/service/finance.go
@@ -0,0 +1,167 @@
+package service
+
+import (
+	"database/sql"
+	"time"
+
+	"github.com/daniil/homelab-api/internal/model"
+	"github.com/daniil/homelab-api/internal/repository"
+)
+
+type FinanceService struct {
+	repo *repository.FinanceRepository
+}
+
+func NewFinanceService(repo *repository.FinanceRepository) *FinanceService {
+	return &FinanceService{repo: repo}
+}
+
+// --- Categories ---
+
+func (s *FinanceService) ListCategories(userID int64) ([]model.FinanceCategory, error) {
+	// Auto-seed if user has no categories
+	has, err := s.repo.HasCategories(userID)
+	if err != nil {
+		return nil, err
+	}
+	if !has {
+		if err := s.repo.SeedDefaultCategories(userID); err != nil {
+			return nil, err
+		}
+	}
+
+	cats, err := s.repo.ListCategories(userID)
+	if err != nil {
+		return nil, err
+	}
+	if cats == nil {
+		cats = []model.FinanceCategory{}
+	}
+	return cats, nil
+}
+
+func (s *FinanceService) CreateCategory(userID int64, req *model.CreateFinanceCategoryRequest) (*model.FinanceCategory, error) {
+	cat := &model.FinanceCategory{
+		UserID:    userID,
+		Name:      req.Name,
+		Emoji:     req.Emoji,
+		Type:      req.Type,
+		Color:     defaultString(req.Color, "#6366f1"),
+		SortOrder: req.SortOrder,
+	}
+	if req.Budget != nil {
+		cat.Budget = sql.NullFloat64{Float64: *req.Budget, Valid: true}
+	}
+	if err := s.repo.CreateCategory(cat); err != nil {
+		return nil, err
+	}
+	cat.ProcessForJSON()
+	return cat, nil
+}
+
+func (s *FinanceService) UpdateCategory(id, userID int64, req *model.UpdateFinanceCategoryRequest) (*model.FinanceCategory, error) {
+	cat, err := s.repo.GetCategory(id, userID)
+	if err != nil {
+		return nil, err
+	}
+	if req.Name != nil {
+		cat.Name = *req.Name
+	}
+	if req.Emoji != nil {
+		cat.Emoji = *req.Emoji
+	}
+	if req.Type != nil {
+		cat.Type = *req.Type
+	}
+	if req.Budget != nil {
+		cat.Budget = sql.NullFloat64{Float64: *req.Budget, Valid: true}
+	}
+	if req.Color != nil {
+		cat.Color = *req.Color
+	}
+	if req.SortOrder != nil {
+		cat.SortOrder = *req.SortOrder
+	}
+	if err := s.repo.UpdateCategory(cat); err != nil {
+		return nil, err
+	}
+	cat.ProcessForJSON()
+	return cat, nil
+}
+
+func (s *FinanceService) DeleteCategory(id, userID int64) error {
+	return s.repo.DeleteCategory(id, userID)
+}
+
+// --- Transactions ---
+
+func (s *FinanceService) ListTransactions(userID int64, month, year int, categoryID *int64, txType, search string, limit, offset int) ([]model.FinanceTransaction, error) {
+	txs, err := s.repo.ListTransactions(userID, month, year, categoryID, txType, search, limit, offset)
+	if err != nil {
+		return nil, err
+	}
+	if txs == nil {
+		txs = []model.FinanceTransaction{}
+	}
+	return txs, nil
+}
+
+func (s *FinanceService) CreateTransaction(userID int64, req *model.CreateFinanceTransactionRequest) (*model.FinanceTransaction, error) {
+	date, err := time.Parse("2006-01-02", req.Date)
+	if err != nil {
+		date = time.Now()
+	}
+	tx := &model.FinanceTransaction{
+		UserID:      userID,
+		CategoryID:  req.CategoryID,
+		Type:        req.Type,
+		Amount:      req.Amount,
+		Description: req.Description,
+		Date:        date,
+	}
+	if err := s.repo.CreateTransaction(tx); err != nil {
+		return nil, err
+	}
+	return tx, nil
+}
+
+func (s *FinanceService) UpdateTransaction(id, userID int64, req *model.UpdateFinanceTransactionRequest) (*model.FinanceTransaction, error) {
+	tx, err := s.repo.GetTransaction(id, userID)
+	if err != nil {
+		return nil, err
+	}
+	if req.CategoryID != nil {
+		tx.CategoryID = *req.CategoryID
+	}
+	if req.Type != nil {
+		tx.Type = *req.Type
+	}
+	if req.Amount != nil {
+		tx.Amount = *req.Amount
+	}
+	if req.Description != nil {
+		tx.Description = *req.Description
+	}
+	if req.Date != nil {
+		parsed, err := time.Parse("2006-01-02", *req.Date)
+		if err == nil {
+			tx.Date = parsed
+		}
+	}
+	if err := s.repo.UpdateTransaction(tx); err != nil {
+		return nil, err
+	}
+	return tx, nil
+}
+
+func (s *FinanceService) DeleteTransaction(id, userID int64) error {
+	return s.repo.DeleteTransaction(id, userID)
+}
+
+func (s *FinanceService) GetSummary(userID int64, month, year int) (*model.FinanceSummary, error) {
+	return s.repo.GetSummary(userID, month, year)
+}
+
+func (s *FinanceService) GetAnalytics(userID int64, months int) (*model.FinanceAnalytics, error) {
+	return s.repo.GetAnalytics(userID, months)
+}