amount.go

// Author(s): Michael Koeppl

package dinero

import (
	"fmt"

	"github.com/shopspring/decimal"
)

// Amount represents a money value in a given currency.
type Amount struct {
	Value    decimal.Decimal
	Currency Currency
}

// ConvertToMv converts Amount a to another target currency. It returns the converted
// Amount or an error.
func (a Amount) ConvertToMv(target Currency) (*Amount, error) {
	resval := &Amount{}
	rate, err := rate(currencyCodes[a.Currency], currencyCodes[target])
	if err != nil {
		return nil, err
	}
	resval.Value = a.Value.Mul(rate)
	resval.Currency = target
	return resval, nil
}

// ConvertTo converts Amount a to another target currency. It returns the converted
// value as a float64 or an error.
func (a Amount) ConvertTo(target Currency) (decimal.Decimal, error) {
	res, err := a.ConvertToMv(target)
	if err != nil {
		return decimal.Zero, err
	}
	return res.Value, nil
}

// String returns the amount with its currency symbol in the
// predefined format "<value> <symbol>".
func (a Amount) String() string {
	return fmt.Sprintf("%s %s", a.Value.String(), currencySymbols[a.Currency])
}

// NewAmount returns an Amount with the given value and currency.
// It's sort of a helper function, making the creation of an Amount simpler.
func NewAmount(value decimal.Decimal, curr Currency) Amount {
	return Amount{Value: value, Currency: curr}
}

// NewAmountFromFloat returns an Amount with the given value (provided as float) and currency.
// It's sort of a helper function, making the creation of an Amount from a float simpler.
func NewAmountFromFloat(value float64, curr Currency) Amount {
	return Amount{Value: decimal.NewFromFloat(value), Currency: curr}
}

// NewAmountFromString tries creating a new amount from the provided string.
// Should the conversion fail, an error is returned. If the conversion was
// successful, the function returns the new Amount.
func NewAmountFromString(value string, curr Currency) (Amount, error) {
	dec, err := decimal.NewFromString(value)
	if err != nil {
		return Amount{}, err
	}
	return Amount{Value: dec, Currency: curr}, nil
}