package auth

// §13.5 interop capture (2026-09-01): three codes computed by an independent
// Python-stdlib TOTP implementation at recorded wall-clock Unix seconds, for
// the shared RFC secret. Cross-implementation agreement — the Python code
// also reproduced RFC 4226 App D counter 0 = 755224, anchoring it to the
// same algorithm. The Go implementation must produce identical codes at the
// same instants, and VerifyWindow(0) must accept each at its capture time.

import (
	"testing"
	"time"
)

func TestInteropCapturePythonTOTP(t *testing.T) {
	captures := []struct {
		unix int64
		code string
	}{
		{1788266430, "398267"},
		{1788266460, "060110"},
		{1788266490, "612712"},
	}
	for _, c := range captures {
		at := time.Unix(c.unix, 0)
		step := Counter(at, 30*time.Second)
		got, err := HOTP(totpSecret, step, 6)
		if err != nil {
			t.Fatalf("HOTP t=%d: %v", c.unix, err)
		}
		if got != c.code {
			t.Errorf("t=%d: Go produced %s, independent impl produced %s", c.unix, got, c.code)
		}
		// window=0: the code must verify at exactly its capture instant.
		if _, err := VerifyWindow(0, totpSecret, c.code, at); err != nil {
			t.Errorf("t=%d: capture code %s failed window-0 verify: %v", c.unix, c.code, err)
		}
	}
}