130 lines
3.2 KiB
Go
130 lines
3.2 KiB
Go
package decimal
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import (
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"math/big"
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"github.com/tech/sendico/pkg/merrors"
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)
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// Money represents a monetary amount with currency and precision handling
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type Money struct {
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Amount *big.Rat
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Currency string
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Scale uint32 // decimal places for this currency
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}
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// NewMoney creates a new Money value from a decimal string
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func NewMoney(amount, currency string, scale uint32) (*Money, error) {
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rat, err := RatFromString(amount)
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if err != nil {
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return nil, err
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}
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return &Money{
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Amount: rat,
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Currency: currency,
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Scale: scale,
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}, nil
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}
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// Add adds two money values (must have same currency)
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func (m *Money) Add(other *Money) (*Money, error) {
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if m.Currency != other.Currency {
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return nil, merrors.InvalidArgument("decimal: currency mismatch: " + m.Currency + " != " + other.Currency)
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}
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return &Money{
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Amount: AddRat(m.Amount, other.Amount),
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Currency: m.Currency,
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Scale: m.Scale,
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}, nil
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}
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// Sub subtracts two money values (must have same currency)
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func (m *Money) Sub(other *Money) (*Money, error) {
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if m.Currency != other.Currency {
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return nil, merrors.InvalidArgument("decimal: currency mismatch: " + m.Currency + " != " + other.Currency)
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}
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return &Money{
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Amount: SubRat(m.Amount, other.Amount),
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Currency: m.Currency,
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Scale: m.Scale,
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}, nil
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}
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// Mul multiplies money by a rational number (for fees, percentages, etc.)
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func (m *Money) Mul(factor *big.Rat) *Money {
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return &Money{
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Amount: MulRat(m.Amount, factor),
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Currency: m.Currency,
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Scale: m.Scale,
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}
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}
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// Div divides money by a rational number
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func (m *Money) Div(divisor *big.Rat) (*Money, error) {
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result, err := DivRat(m.Amount, divisor)
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if err != nil {
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return nil, err
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}
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return &Money{
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Amount: result,
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Currency: m.Currency,
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Scale: m.Scale,
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}, nil
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}
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// Negate returns the negative of this money value
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func (m *Money) Negate() *Money {
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return &Money{
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Amount: NegRat(m.Amount),
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Currency: m.Currency,
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Scale: m.Scale,
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}
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}
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// Round rounds the money to its scale using the specified rounding mode
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func (m *Money) Round(mode RoundingMode) (*Money, error) {
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rounded, err := RoundRatToScale(m.Amount, m.Scale, mode)
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if err != nil {
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return nil, err
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}
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return &Money{
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Amount: rounded,
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Currency: m.Currency,
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Scale: m.Scale,
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}, nil
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}
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// String returns the formatted money value
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func (m *Money) String() string {
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return FormatRat(m.Amount, m.Scale) + " " + m.Currency
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}
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// StringAmount returns just the formatted amount
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func (m *Money) StringAmount() string {
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return FormatRat(m.Amount, m.Scale)
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}
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// IsZero checks if the money amount is zero
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func (m *Money) IsZero() bool {
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return IsZero(m.Amount)
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}
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// IsPositive checks if the money amount is positive
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func (m *Money) IsPositive() bool {
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return IsPositive(m.Amount)
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}
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// IsNegative checks if the money amount is negative
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func (m *Money) IsNegative() bool {
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return IsNegative(m.Amount)
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}
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// Cmp compares two money values (must have same currency)
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// Returns -1 if m < other, 0 if m == other, 1 if m > other
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func (m *Money) Cmp(other *Money) (int, error) {
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if m.Currency != other.Currency {
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return 0, merrors.InvalidArgument("decimal: currency mismatch: " + m.Currency + " != " + other.Currency)
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}
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return CmpRat(m.Amount, other.Amount), nil
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}
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