package sm2

import (
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"encoding/hex"
	"math/big"
	"reflect"
	"testing"
)

func Test_kdf(t *testing.T) {
	x2, _ := new(big.Int).SetString("64D20D27D0632957F8028C1E024F6B02EDF23102A566C932AE8BD613A8E865FE", 16)
	y2, _ := new(big.Int).SetString("58D225ECA784AE300A81A2D48281A828E1CEDF11C4219099840265375077BF78", 16)

	expected := "006e30dae231b071dfad8aa379e90264491603"

	result, success := kdf(append(x2.Bytes(), y2.Bytes()...), 19)
	if !success {
		t.Fatalf("failed")
	}

	resultStr := hex.EncodeToString(result)

	if expected != resultStr {
		t.Fatalf("expected %s, real value %s", expected, resultStr)
	}
}

func Test_encryptDecrypt(t *testing.T) {
	priv, _ := ecdsa.GenerateKey(P256(), rand.Reader)
	tests := []struct {
		name      string
		plainText string
	}{
		// TODO: Add test cases.
		{"less than 32", "encryption standard"},
		{"equals 32", "encryption standard encryption "},
		{"long than 32", "encryption standard encryption standard"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			ciphertext, err := Encrypt(rand.Reader, &priv.PublicKey, []byte(tt.plainText))
			if err != nil {
				t.Fatalf("encrypt failed %v", err)
			}
			plaintext, err := Decrypt(priv, ciphertext)
			if err != nil {
				t.Fatalf("decrypt failed %v", err)
			}
			if !reflect.DeepEqual(string(plaintext), tt.plainText) {
				t.Errorf("Decrypt() = %v, want %v", string(plaintext), tt.plainText)
			}
		})
	}
}

func benchmarkEncrypt(b *testing.B, curve elliptic.Curve, plaintext string) {
	for i := 0; i < b.N; i++ {
		priv, _ := ecdsa.GenerateKey(curve, rand.Reader)
		Encrypt(rand.Reader, &priv.PublicKey, []byte(plaintext))
	}
}

func BenchmarkLessThan32_P256(b *testing.B) {
	benchmarkEncrypt(b, elliptic.P256(), "encryption standard")
}

func BenchmarkLessThan32_P256SM2(b *testing.B) {
	benchmarkEncrypt(b, P256(), "encryption standard")
}

func BenchmarkMoreThan32_P256(b *testing.B) {
	benchmarkEncrypt(b, elliptic.P256(), "encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard")
}

func BenchmarkMoreThan32_P256SM2(b *testing.B) {
	benchmarkEncrypt(b, P256(), "encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard encryption standard")
}