init

2026-01-25 21:59:00 +08:00
parent 7fd537bef3
commit 4cad3f0250
118 changed files with 30473 additions and 0 deletions
--- a/internal/service/exchange_rate_service.go
+++ b/internal/service/exchange_rate_service.go
@@ -0,0 +1,186 @@
+package service
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"accounting-app/internal/models"
+	"accounting-app/internal/repository"
+)
+
+// Common exchange rate service errors
+var (
+	ErrInvalidRate         = errors.New("exchange rate must be positive")
+	ErrInvalidEffectiveDate = errors.New("effective date cannot be in the future")
+)
+
+// ExchangeRateService handles business logic for exchange rates
+type ExchangeRateService struct {
+	repo *repository.ExchangeRateRepository
+}
+
+// NewExchangeRateService creates a new ExchangeRateService instance
+func NewExchangeRateService(repo *repository.ExchangeRateRepository) *ExchangeRateService {
+	return &ExchangeRateService{repo: repo}
+}
+
+// CreateExchangeRate creates a new exchange rate
+func (s *ExchangeRateService) CreateExchangeRate(rate *models.ExchangeRate) error {
+	// Validate rate value
+	if rate.Rate <= 0 {
+		return ErrInvalidRate
+	}
+
+	// Validate effective date (should not be in the future)
+	if rate.EffectiveDate.After(time.Now()) {
+		return ErrInvalidEffectiveDate
+	}
+
+	// Validate currencies are different
+	if rate.FromCurrency == rate.ToCurrency {
+		return repository.ErrSameCurrency
+	}
+
+	return s.repo.Create(rate)
+}
+
+// GetExchangeRateByID retrieves an exchange rate by its ID
+func (s *ExchangeRateService) GetExchangeRateByID(id uint) (*models.ExchangeRate, error) {
+	return s.repo.GetByID(id)
+}
+
+// GetAllExchangeRates retrieves all exchange rates
+func (s *ExchangeRateService) GetAllExchangeRates() ([]models.ExchangeRate, error) {
+	return s.repo.GetAll()
+}
+
+// UpdateExchangeRate updates an existing exchange rate
+func (s *ExchangeRateService) UpdateExchangeRate(rate *models.ExchangeRate) error {
+	// Validate rate value
+	if rate.Rate <= 0 {
+		return ErrInvalidRate
+	}
+
+	// Validate effective date (should not be in the future)
+	if rate.EffectiveDate.After(time.Now()) {
+		return ErrInvalidEffectiveDate
+	}
+
+	// Validate currencies are different
+	if rate.FromCurrency == rate.ToCurrency {
+		return repository.ErrSameCurrency
+	}
+
+	return s.repo.Update(rate)
+}
+
+// DeleteExchangeRate deletes an exchange rate by its ID
+func (s *ExchangeRateService) DeleteExchangeRate(id uint) error {
+	return s.repo.Delete(id)
+}
+
+// GetExchangeRateByCurrencyPair retrieves the most recent exchange rate for a currency pair
+func (s *ExchangeRateService) GetExchangeRateByCurrencyPair(fromCurrency, toCurrency models.Currency) (*models.ExchangeRate, error) {
+	return s.repo.GetByCurrencyPair(fromCurrency, toCurrency)
+}
+
+// GetExchangeRateByCurrencyPairAndDate retrieves the exchange rate for a currency pair on a specific date
+func (s *ExchangeRateService) GetExchangeRateByCurrencyPairAndDate(fromCurrency, toCurrency models.Currency, date time.Time) (*models.ExchangeRate, error) {
+	return s.repo.GetByCurrencyPairAndDate(fromCurrency, toCurrency, date)
+}
+
+// GetLatestExchangeRates retrieves the most recent exchange rate for each currency pair
+func (s *ExchangeRateService) GetLatestExchangeRates() ([]models.ExchangeRate, error) {
+	return s.repo.GetLatestRates()
+}
+
+// ConvertCurrency converts an amount from one currency to another using the most recent exchange rate
+func (s *ExchangeRateService) ConvertCurrency(amount float64, fromCurrency, toCurrency models.Currency) (float64, error) {
+	// If currencies are the same, return the original amount
+	if fromCurrency == toCurrency {
+		return amount, nil
+	}
+
+	// Get the exchange rate
+	rate, err := s.repo.GetByCurrencyPair(fromCurrency, toCurrency)
+	if err != nil {
+		// If direct rate not found, try inverse rate
+		if errors.Is(err, repository.ErrExchangeRateNotFound) {
+			inverseRate, inverseErr := s.repo.GetByCurrencyPair(toCurrency, fromCurrency)
+			if inverseErr != nil {
+				return 0, fmt.Errorf("no exchange rate found for %s to %s: %w", fromCurrency, toCurrency, err)
+			}
+			// Use inverse rate: 1 / rate
+			if inverseRate.Rate == 0 {
+				return 0, errors.New("invalid inverse exchange rate (zero)")
+			}
+			return amount / inverseRate.Rate, nil
+		}
+		return 0, err
+	}
+
+	return amount * rate.Rate, nil
+}
+
+// ConvertCurrencyOnDate converts an amount from one currency to another using the exchange rate on a specific date
+func (s *ExchangeRateService) ConvertCurrencyOnDate(amount float64, fromCurrency, toCurrency models.Currency, date time.Time) (float64, error) {
+	// If currencies are the same, return the original amount
+	if fromCurrency == toCurrency {
+		return amount, nil
+	}
+
+	// Get the exchange rate for the specific date
+	rate, err := s.repo.GetByCurrencyPairAndDate(fromCurrency, toCurrency, date)
+	if err != nil {
+		// If direct rate not found, try inverse rate
+		if errors.Is(err, repository.ErrExchangeRateNotFound) {
+			inverseRate, inverseErr := s.repo.GetByCurrencyPairAndDate(toCurrency, fromCurrency, date)
+			if inverseErr != nil {
+				return 0, fmt.Errorf("no exchange rate found for %s to %s on %s: %w", fromCurrency, toCurrency, date.Format("2006-01-02"), err)
+			}
+			// Use inverse rate: 1 / rate
+			if inverseRate.Rate == 0 {
+				return 0, errors.New("invalid inverse exchange rate (zero)")
+			}
+			return amount / inverseRate.Rate, nil
+		}
+		return 0, err
+	}
+
+	return amount * rate.Rate, nil
+}
+
+// GetExchangeRateByCurrency retrieves all exchange rates involving a specific currency
+func (s *ExchangeRateService) GetExchangeRateByCurrency(currency models.Currency) ([]models.ExchangeRate, error) {
+	return s.repo.GetByCurrency(currency)
+}
+
+// SetExchangeRate creates or updates an exchange rate for a currency pair
+// This is a convenience method for users to set rates without worrying about create vs update
+func (s *ExchangeRateService) SetExchangeRate(fromCurrency, toCurrency models.Currency, rate float64, effectiveDate time.Time) error {
+	// Validate rate value
+	if rate <= 0 {
+		return ErrInvalidRate
+	}
+
+	// Validate effective date
+	if effectiveDate.After(time.Now()) {
+		return ErrInvalidEffectiveDate
+	}
+
+	// Validate currencies are different
+	if fromCurrency == toCurrency {
+		return repository.ErrSameCurrency
+	}
+
+	// Create new exchange rate entry
+	exchangeRate := &models.ExchangeRate{
+		FromCurrency:  fromCurrency,
+		ToCurrency:    toCurrency,
+		Rate:          rate,
+		EffectiveDate: effectiveDate,
+	}
+
+	return s.repo.Create(exchangeRate)
+}