package server

import "testing"

// TestFormatCurrency covers finding #12: formatCurrency used to hardcode a
// "$" prefix regardless of currency and always divided by 100, which is
// wrong for zero-decimal currencies (e.g. JPY). The fixed formatter must
// prefix the uppercase ISO-4217 code (no symbol) and only divide by 100 for
// currencies with a minor unit.
func TestFormatCurrency(t *testing.T) {
	cases := []struct {
		name     string
		amount   int32
		currency string
		want     string
	}{
		{"usd lowercase code uppercases", 1000, "usd", "USD 10.00"},
		{"usd already uppercase", 1000, "USD", "USD 10.00"},
		{"eur no dollar sign", 1000, "eur", "EUR 10.00"},
		{"sub-dollar amount", 99, "usd", "USD 0.99"},
		{"zero amount", 0, "usd", "USD 0.00"},
		{"jpy zero-decimal not divided by 100", 1000, "jpy", "JPY 1000"},
		{"jpy uppercase input", 500, "JPY", "JPY 500"},
		{"krw zero-decimal", 15000, "krw", "KRW 15000"},
		{"negative amount preserved", -500, "usd", "USD -5.00"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got := formatCurrency(tc.amount, tc.currency)
			if got != tc.want {
				t.Errorf("formatCurrency(%d, %q) = %q, want %q", tc.amount, tc.currency, got, tc.want)
			}
		})
	}
}