package gcd

import (
	"math/big"
	"testing"
	"testing/quick"
)

func TestGCD(t *testing.T) {
	f := func(u, v uint8) bool {
		if u == 0 || v == 0 {
			return true
		}
		result := GCD(uint64(u), uint64(v))

		bigU := big.NewInt(int64(u))
		bigV := big.NewInt(int64(v))
		bigU.GCD(nil, nil, bigU, bigV)

		ok := bigU.Int64() == int64(result)
		if !ok {
			t.Logf("we got %d, they got %d", result, bigU.Int64())
		}
		return ok
	}

	err := quick.Check(f, &quick.Config{})
	if err != nil {
		t.Fatal(err)
	}
}

func BenchmarkBigGCD(b *testing.B) {
	for i := 0; i < b.N; i++ {
		u := big.NewInt(int64(i * 2))
		v := big.NewInt(int64(i * 3))
		u.GCD(nil, nil, u, v)
	}
}

// BenchmarkBigGCD-4        3000000               467 ns/op             320 B/op          8 allocs/op
// BenchmarkBinaryGCD-4    100000000               12.2 ns/op             0 B/op          0 allocs/op
func BenchmarkBinaryGCD(b *testing.B) {
	for i := 0; i < b.N; i++ {
		u := uint64(i * 2)
		v := uint64(i * 3)
		math.GCD(u, v)
	}
}