package tax

// nordicStandardRates maps country code -> default standard VAT rate in basis
// points of a percent (2500 = 25%).
var nordicStandardRates = map[string]int{
	"SE": 2500,
	"NO": 2500,
	"DK": 2500,
	"FI": 2550, // 25.5% as of 2024 — exact in basis points, no truncation
}

// Nordic implements Provider for the Nordic countries (SE, NO, DK, FI).
// It encodes the standard statutory VAT rates (basis points):
//
//	SE:  25 %   (2500)
//	NO:  25 %   (2500)
//	DK:  25 %   (2500)
//	FI:  25.5 % (2550)
//
// Rates are integer basis points, so fractional rates (FI 25.5) are represented
// exactly — no float, no truncation.
//
// Nordic does not make network calls — all logic is local math. An external
// provider (Avalara, TaxJar) can be added by implementing Provider and
// switching on TAX_PROVIDER.
type Nordic struct {
	defaultCountry string
}

// NewNordic returns a Nordic provider. defaultCountry is used when
// DefaultTaxRate is called with an empty country code; it defaults to "SE"
// if empty.
func NewNordic(defaultCountry string) *Nordic {
	if defaultCountry == "" {
		defaultCountry = "SE"
	}
	return &Nordic{defaultCountry: defaultCountry}
}

var _ Provider = (*Nordic)(nil)

func (p *Nordic) Name() string { return "nordic" }

func (p *Nordic) Compute(total int64, taxRate int) int64 {
	return Compute(total, taxRate)
}

func (p *Nordic) DefaultTaxRate(country string) int {
	if country == "" {
		country = p.defaultCountry
	}
	if rate, ok := nordicStandardRates[country]; ok {
		return rate
	}
	return nordicStandardRates[p.defaultCountry]
}