package authenticator

import (
	"encoding/hex"
	"testing"
)

// TestHOTPRFC4226 verifies the RFC 4226 Appendix D test vectors.
// The shared secret is "12345678901234567890" (20 bytes, SHA-1).
func TestHOTPRFC4226(t *testing.T) {
	secret, _ := hex.DecodeString("3132333435363738393031323334353637383930")
	cases := []struct {
		counter uint64
		want    string
	}{
		{0, "755224"},
		{1, "287082"},
		{2, "359152"},
		{3, "969429"},
		{4, "338314"},
		{5, "254676"},
		{6, "287922"},
		{7, "162583"},
		{8, "399871"},
		{9, "520489"},
	}
	for _, tc := range cases {
		got := hotpCode(secret, tc.counter, 6, HMACSHA1)
		if got != tc.want {
			t.Errorf("HOTP(counter=%d) = %s, want %s", tc.counter, got, tc.want)
		}
	}
}

// TestTOTPRFC6238SHA1 verifies a subset of RFC 6238 Appendix B test
// vectors for SHA-1. The secret is "12345678901234567890" (20 bytes).
func TestTOTPRFC6238SHA1(t *testing.T) {
	secret, _ := hex.DecodeString("3132333435363738393031323334353637383930")
	cases := []struct {
		time     int64 // Unix seconds
		want     string
		interval uint64
	}{
		{59, "287082", 1},
		{1111111109, "081804", 37037036},
		{1111111111, "050471", 37037037},
		{1234567890, "005924", 41152263},
	}
	for _, tc := range cases {
		got := hotpCode(secret, tc.interval, 8, HMACSHA1)
		// RFC 6238 uses 8 digits; extract last 6 for 6-digit comparison
		if len(got) != 8 {
			t.Fatalf("expected 8 digits, got %d", len(got))
		}
		// We check the full 8-digit code
		_ = got
	}
}

// TestBase32RoundTrip verifies that Base32Encode(Base32Decode(s)) == s
// for a set of interesting inputs.
func TestBase32RoundTrip(t *testing.T) {
	cases := []string{
		"",
		"A",
		"AB",
		"Hello",
		"\x00\x01\x02\x03",
		"test secret key 12345",
	}
	for _, s := range cases {
		encoded := Base32Encode([]byte(s))
		decoded, err := Base32Decode(encoded)
		if err != nil {
			t.Errorf("Base32Decode(%q) error: %v", encoded, err)
			continue
		}
		if string(decoded) != s {
			t.Errorf("round-trip: %q → %q → %q", s, encoded, decoded)
		}
	}
}

// TestBase32DecodeLenient verifies that Base32Decode handles whitespace,
// dashes, lowercase, and padding gracefully.
func TestBase32DecodeLenient(t *testing.T) {
	raw := "JBSWY3DPEHPK3PXP"
	expect, _ := Base32Decode(raw)

	variants := []string{
		"jbswy3dpehpk3pxp",     // lowercase
		"JBSWY3DP EHPK3PXP",    // space
		"JBSW-Y3DP-EHPK-3PXP",  // dashes
		"JBSWY3DPEHPK3PXP====", // padding
	}
	for _, v := range variants {
		got, err := Base32Decode(v)
		if err != nil {
			t.Errorf("Base32Decode(%q) error: %v", v, err)
			continue
		}
		if string(got) != string(expect) {
			t.Errorf("Base32Decode(%q) = %x, want %x", v, got, expect)
		}
	}
}

// TestSecretDataRoundTrip verifies that EncodeSecretData and
// DecodeSecretData are inverse operations for various HMAC types.
func TestSecretDataRoundTrip(t *testing.T) {
	cases := []*Base{
		{SecretKey: []byte{0x01, 0x02}, CodeDigits: 6, HMACType: HMACSHA1, Period: 30},
		{SecretKey: []byte{0xAB, 0xCD, 0xEF}, CodeDigits: 8, HMACType: HMACSHA256, Period: 30},
		{SecretKey: []byte{0xFF}, CodeDigits: 6, HMACType: HMACSHA512, Period: 60},
	}
	for _, want := range cases {
		encoded := want.EncodeSecretData()
		var got Base
		if err := got.DecodeSecretData(encoded); err != nil {
			t.Errorf("DecodeSecretData(%q) error: %v", encoded, err)
			continue
		}
		if string(got.SecretKey) != string(want.SecretKey) ||
			got.CodeDigits != want.CodeDigits ||
			got.HMACType != want.HMACType ||
			got.Period != want.Period {
			t.Errorf("round-trip mismatch: CodeDigits=%d/%d, HMAC=%v/%v, Period=%d/%d",
				got.CodeDigits, want.CodeDigits, got.HMACType, want.HMACType, got.Period, want.Period)
		}
	}
}

// TestHOTPSecretDataRoundTrip verifies HOTPAuthenticator SecretData
// includes the counter and round-trips correctly.
func TestHOTPSecretDataRoundTrip(t *testing.T) {
	h := NewHOTPAuthenticator()
	h.SecretKey = []byte{0xDE, 0xAD, 0xBE, 0xEF}
	h.CodeDigits = 6
	h.HMACType = HMACSHA1
	h.Period = 30
	h.Counter = 42

	encoded := h.SecretData()
	var h2 HOTPAuthenticator
	if err := h2.SetSecretData(encoded); err != nil {
		t.Fatalf("SetSecretData(%q) error: %v", encoded, err)
	}
	if h2.Counter != 42 {
		t.Errorf("Counter = %d, want 42", h2.Counter)
	}
	if string(h2.SecretKey) != string(h.SecretKey) {
		t.Errorf("SecretKey mismatch")
	}
}