//
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package satp

import (
	"bytes"
	"crypto/aes"
	"math/rand"
	"testing"
)

func TestAESCTRKeyDerivationNew(t *testing.T) {
	var buffer [100]byte
	rand.Read(buffer[:])

	testvectors := []struct {
		key   []byte
		salt  []byte
		valid bool
	}{
		{[]byte{}, []byte{}, false},
		{[]byte{}, buffer[:], false},
		{buffer[:], []byte{}, false},
		{[]byte{}, buffer[:14], false},
		{buffer[:16], []byte{}, false},
		{buffer[:16], buffer[:14], true},
	}

	for _, vector := range testvectors {
		for _, role := range []KDRole{RoleLeft, RoleRight} {
			_, err := NewAESCTRKeyDerivation(vector.key, vector.salt, role)
			if vector.valid {
				if err != nil {
					t.Fatal("unexpected error:", err)
				}
			} else {
				if err == nil {
					t.Fatalf("creating aes-ctr key derivation with key %v and salt %v should give an error", vector.key, vector.salt)
				}
			}
		}
	}
}

func TestAESCTRKeyDerivationGenerateCtr(t *testing.T) {
	testvectors := []struct {
		salt           []byte
		role           KDRole
		dir            Direction
		usage          KeyUsage
		sequenceNumber uint32
		ctr            []byte
	}{
		{[]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, RoleLeft, Outbound, UsageEncryptKey, 0x12345678,
			[]byte{0, 0, 0, 0, 0, 0, 0x35, 0x6A, 0x19, 0x2B, 0x12, 0x34, 0x56, 0x78, 0, 0}},
		{[]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, RoleRight, Outbound, UsageEncryptSalt, 0x01020304,
			[]byte{0, 0, 0, 0, 0, 0, 0x1B, 0x64, 0x53, 0x89, 0x01, 0x02, 0x03, 0x04, 0, 0}},
		{[]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, RoleLeft, Outbound, UsageAuthKey, 0xdeadbeef,
			[]byte{0, 0, 0, 0, 0, 0, 0xAC, 0x34, 0x78, 0xD6, 0xDE, 0xAD, 0xBE, 0xEF, 0, 0}},
		{[]byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, RoleLeft, Outbound, UsageAuthKey, 0xdeadbeef,
			[]byte{0, 1, 2, 3, 4, 5, 0xAA, 0x33, 0x70, 0xDF, 0xD4, 0xA6, 0xB2, 0xE2, 0, 0}},
		{[]byte{0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xF0, 0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC}, RoleLeft, Outbound, UsageEncryptSalt, 0x01020304,
			[]byte{0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xA9, 0x2E, 0x7A, 0xEE, 0x57, 0x7A, 0x99, 0xB8, 0, 0}},
	}

	for _, vector := range testvectors {
		key := [aes.BlockSize]byte{}
		kd, err := NewAESCTRKeyDerivation(key[:], vector.salt, vector.role)
		if err != nil {
			t.Fatal("unexpected error:", err)
		}
		aesCTR := kd.(*AESCTRKeyDerivation)

		ctr := [aes.BlockSize]byte{}
		aesCTR.generateCTR(vector.dir, vector.usage, vector.sequenceNumber, ctr[:])
		if bytes.Compare(ctr[:], vector.ctr) != 0 {
			t.Fatalf("resulting ctr is invalid, is: '%v', should be '%v'", ctr[:], vector.ctr)
		}
	}
}

func TestAESCTRKeyDerivationGenerate(t *testing.T) {
	key := []byte{0x77, 0x67, 0xA3, 0x90, 0x3E, 0xB9, 0x22, 0x06, 0x87, 0xBF, 0xF8, 0xA1, 0x4E, 0x94, 0x0F, 0xA7}
	salt := []byte{0x3D, 0x58, 0x3F, 0xC6, 0x70, 0xA9, 0x6B, 0xCF, 0x92, 0xDA, 0x27, 0x0D, 0x07, 0x67}
	kdLeft, err := NewAESCTRKeyDerivation(key, salt, RoleLeft)
	if err != nil {
		t.Fatal("unexpected error:", err)
	}
	kdRight, err := NewAESCTRKeyDerivation(key, salt, RoleRight)
	if err != nil {
		t.Fatal("unexpected error:", err)
	}

	testvectors := []struct {
		kd             KeyDerivation
		dir            Direction
		usage          KeyUsage
		sequenceNumber uint32
		out            []byte
	}{
		{kdLeft, Outbound, UsageEncryptKey, 0,
			[]byte{0x46, 0x04, 0x12, 0x67, 0x0C, 0x7A, 0x20, 0x07, 0x67, 0xC5, 0x9A, 0xB4, 0xBE, 0x2E, 0xBE, 0x50,
				0xE9, 0xBC, 0x04, 0x7C, 0x17, 0x54, 0x73, 0x02, 0x4A, 0x54, 0x28, 0x44, 0x6F, 0xFA, 0xD2, 0xB6}},
		{kdLeft, Inbound, UsageEncryptKey, 0x0012CA37,
			[]byte{0x93, 0xEE, 0xC4, 0xD4, 0x94, 0xDA, 0x29, 0x72, 0x0C, 0xF5, 0xB6, 0x1D, 0x45, 0x3F, 0xA1, 0x19,
				0xB0, 0x31, 0xB1, 0x7D, 0xA3, 0x78, 0x2C, 0x7A, 0x72, 0x19, 0x39, 0x4E, 0xEE, 0x40, 0x52, 0xDA}},
		{kdRight, Outbound, UsageEncryptSalt, 0x0012CA37,
			[]byte{0x7C, 0x20, 0x7D, 0x35, 0xAD, 0x9C, 0xED, 0xC6, 0xE6, 0x16, 0xE4, 0xA9, 0x36, 0x3C, 0x49, 0xAA,
				0xF4, 0xA9, 0x59, 0x0D, 0x6A, 0xC1, 0x63, 0xAB, 0x17, 0x3D, 0xA8, 0x9F, 0x3F, 0xD7, 0x10, 0xC3}},
		{kdRight, Outbound, UsageAuthKey, 0xE,
			[]byte{0xE3, 0x26, 0x29, 0x37, 0xED, 0xF1, 0x36, 0x80, 0xB4, 0x8E, 0x6C, 0xF7, 0x7C, 0xEE, 0x8C, 0x49,
				0xEA, 0x70, 0x6D, 0x24, 0x25, 0x35, 0xAF, 0x79, 0x7F, 0x02, 0x7C, 0x59, 0x2C, 0x7E, 0x41, 0x55}},
		{kdRight, Inbound, UsageAuthKey, 0xC,
			[]byte{0x2C, 0xF9, 0x7A, 0x96, 0x17, 0x28, 0x52, 0xFD, 0xF6, 0x57, 0xC4, 0x86, 0x7D, 0xA8, 0x04, 0xE3,
				0xB4, 0x23, 0xA6, 0xAE, 0x66, 0xF8, 0xB9, 0xCC, 0x79, 0x72, 0xA6, 0xB9, 0x54, 0x72, 0x7F, 0xF4}},
	}

	for _, vector := range testvectors {
		out := [32]byte{}
		vector.kd.Generate(vector.dir, vector.usage, vector.sequenceNumber, out[:])
		if bytes.Compare(out[:], vector.out) != 0 {
			t.Fatalf("resulting key material is invalid, is: '%v', should be '%v'", out[:], vector.out)
		}
	}
}

func TestAESCTRKeyDerivationGenerateRepeat(t *testing.T) {
	var buffer [256]byte
	rand.Read(buffer[:])

	testvectors := []struct {
		key            []byte
		salt           []byte
		role           KDRole
		dir            Direction
		usage          KeyUsage
		sequenceNumber uint32
		length         int
	}{
		{buffer[:16], buffer[16:30], RoleLeft, Outbound, UsageEncryptKey, 0x12345678, 23},
		{buffer[32:48], buffer[48:62], RoleLeft, Inbound, UsageEncryptKey, 0x1, 16},
		{buffer[64:80], buffer[80:94], RoleRight, Outbound, UsageEncryptKey, 0x1, 20},
		{buffer[96:112], buffer[112:126], RoleRight, Outbound, UsageEncryptKey, 0x1, 14},
	}

	for _, vector := range testvectors {
		kd, err := NewAESCTRKeyDerivation(vector.key, vector.salt, vector.role)
		if err != nil {
			t.Fatal("unexpected error:", err)
		}

		out1 := make([]byte, vector.length)
		out2 := buffer[128 : 128+vector.length]
		kd.Generate(vector.dir, vector.usage, vector.sequenceNumber, out1)
		kd.Generate(vector.dir, vector.usage, vector.sequenceNumber, out2)

		if bytes.Compare(out1, out2) != 0 {
			t.Fatalf("result of 2 consecutive key generations differ, out1: '%v', out2: '%v'", out1, out2)
		}
	}
}

//
// Benchmarking
//

func BenchmarkAESCTRKeyDerivationGenerateCtr(b *testing.B) {
	var buffer [256]byte
	rand.Read(buffer[:])

	kd, err := NewAESCTRKeyDerivation(buffer[:16], buffer[16:30], RoleRight)
	if err != nil {
		b.Fatal("unexpected error:", err)
	}
	aesCTR := kd.(*AESCTRKeyDerivation)
	ctr := make([]byte, 16)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		aesCTR.generateCTR(Outbound, UsageAuthKey, 0xAA55AA55, ctr)
	}
}

func BenchmarkAESCTRKeyDerivationGenerate(b *testing.B) {
	var buffer [256]byte
	rand.Read(buffer[:])

	kd, err := NewAESCTRKeyDerivation(buffer[:16], buffer[16:30], RoleLeft)
	if err != nil {
		b.Fatal("unexpected error:", err)
	}
	out := make([]byte, 16)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		kd.Generate(Outbound, UsageEncryptKey, 0xdeadbeef, out)
	}
}