platform

tax/nordic.go

@@ -0,0 +1,56 @@
+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]
+}