package twofactor

import (
	"crypto"
	"fmt"
	"testing"
	"time"

	"github.com/benbjohnson/clock"
)

var rfcTotpKey = map[crypto.Hash][]byte{
	crypto.SHA1:   []byte("12345678901234567890"),
	crypto.SHA256: []byte("12345678901234567890123456789012"),
	crypto.SHA512: []byte("1234567890123456789012345678901234567890123456789012345678901234"),
}
var rfcTotpStep uint64 = 30

var rfcTotpTests = []struct {
	Time uint64
	Code string
	T    uint64
	Algo crypto.Hash
}{
	{59, "94287082", 1, crypto.SHA1},
	{59, "46119246", 1, crypto.SHA256},
	{59, "90693936", 1, crypto.SHA512},
	{1111111109, "07081804", 37037036, crypto.SHA1},
	{1111111109, "68084774", 37037036, crypto.SHA256},
	{1111111109, "25091201", 37037036, crypto.SHA512},
	{1111111111, "14050471", 37037037, crypto.SHA1},
	{1111111111, "67062674", 37037037, crypto.SHA256},
	{1111111111, "99943326", 37037037, crypto.SHA512},
	{1234567890, "89005924", 41152263, crypto.SHA1},
	{1234567890, "91819424", 41152263, crypto.SHA256},
	{1234567890, "93441116", 41152263, crypto.SHA512},
	{2000000000, "69279037", 66666666, crypto.SHA1},
	{2000000000, "90698825", 66666666, crypto.SHA256},
	{2000000000, "38618901", 66666666, crypto.SHA512},
	{20000000000, "65353130", 666666666, crypto.SHA1},
	{20000000000, "77737706", 666666666, crypto.SHA256},
	{20000000000, "47863826", 666666666, crypto.SHA512},
}

func TestTotpRFC(t *testing.T) {
	for _, tc := range rfcTotpTests {
		otp := NewTOTP(rfcTotpKey[tc.Algo], 0, rfcTotpStep, 8, tc.Algo)
		if otp.otpCounter(tc.Time) != tc.T {
			fmt.Printf("twofactor: invalid TOTP (t=%d, h=%d)\n", tc.Time, tc.Algo)
			fmt.Printf("\texpected: %d\n", tc.T)
			fmt.Printf("\t  actual: %d\n", otp.otpCounter(tc.Time))
			t.Fail()
		}

		if code := otp.otp(otp.otpCounter(tc.Time)); code != tc.Code {
			fmt.Printf("twofactor: invalid TOTP (t=%d, h=%d)\n", tc.Time, tc.Algo)
			fmt.Printf("\texpected: %s\n", tc.Code)
			fmt.Printf("\t  actual: %s\n", code)
			t.Fail()
		}
	}
}

func TestTOTPTime(t *testing.T) {
	otp := GenerateGoogleTOTP()

	testClock := clock.NewMock()
	testClock.Add(2 * time.Minute)
	SetClock(testClock)

	code := otp.OTP()

	testClock.Add(-1 * time.Minute)
	if newCode := otp.OTP(); newCode == code {
		t.Errorf("twofactor: TOTP: previous code %s shouldn't match code %s", newCode, code)
	}

	testClock.Add(2 * time.Minute)
	if newCode := otp.OTP(); newCode == code {
		t.Errorf("twofactor: TOTP: future code %s shouldn't match code %s", newCode, code)
	}

	testClock.Add(-1 * time.Minute)
	if newCode := otp.OTP(); newCode != code {
		t.Errorf("twofactor: TOTP: current code %s shouldn't match code %s", newCode, code)
	}
}