// build 2^w keys, each having a unique value in the first w bits
func (s *XLSuite) makePermutedKeys(rng *xr.PRNG, w uint) (
	fields []int, // FOR DEBUGGING ONLY
	keys [][]byte) {

	fieldCount := (1 << w) - 1    // we don't want the zero value
	fields = rng.Perm(fieldCount) // so 2^w distinct values
	for i := 0; i < len(fields); i++ {
		fields[i] += 1
	}
	keyLen := uint((int(w)*fieldCount + 7) / 8) // in bytes, rounded up
	keyCount := uint(fieldCount)
	keys = make([][]byte, keyCount)

	for i := uint(0); i < keyCount; i++ {
		key := make([]byte, keyLen) // all zeroes
		if i != uint(0) {
			copy(key, keys[i-1])
		}
		// OR the field into the appropriate byte(s) of the key
		bitOffset := w * i
		whichByte := bitOffset / uint(8)
		whichBit := bitOffset % uint(8)

		// lower half of the field
		key[whichByte] |= byte(fields[i] << whichBit)
		if whichBit+w >= 8 {
			key[whichByte+1] |= byte(fields[i] >> (8 - whichBit))
		}
		keys[i] = key
	}

	return
}

// Create an AES IV and key and an 8-byte salt, then encrypt these and
// the proposed protocol version using the server's comms public key.
func ClientEncryptHello(version1 uint32, ck *rsa.PublicKey, rng *xr.PRNG) (
	cOneShot *AesSession, ciphertext []byte, err error) {

	if rng == nil {
		rng = xr.MakeSystemRNG()
	}
	vBytes := make([]byte, 4)
	vBytes[0] = byte(version1)
	vBytes[1] = byte(version1 >> 8)
	vBytes[2] = byte(version1 >> 16)
	vBytes[3] = byte(version1 >> 24)

	// Generate 32-byte AES key, and 8-byte salt for the Hello
	salty := make([]byte, 2*aes.BlockSize+8+20)
	rng.NextBytes(salty)

	key1 := salty[:2*aes.BlockSize]
	// salt1 := salty[2*aes.BlockSize : 2*aes.BlockSize+8]
	oaep1 := salty[2*aes.BlockSize+8:]
	oaepSalt := bytes.NewBuffer(oaep1)

	sha := sha1.New()
	data := salty[:2*aes.BlockSize+8] // contains key1,salt1
	data = append(data, vBytes...)    // ... plus preferred protocol version

	ciphertext, err = rsa.EncryptOAEP(sha, oaepSalt, ck, data, nil)
	if err == nil {
		cOneShot, err = NewAesSession(key1, rng)
	}
	return
}

func (s *XLSuite) makeHostAndKeys(c *C, rng *xr.PRNG) (
	n *xn.Node, ckPriv, skPriv *rsa.PrivateKey) {

	// XXX names may not be unique
	name := rng.NextFileName(6)
	for {
		first := string(name[0])
		if !strings.Contains(first, "0123456789") &&
			!strings.Contains(name, "-") {
			break
		}
		name = rng.NextFileName(6)
	}
	id := s.makeANodeID(c, rng)
	lfs := "tmp/" + hex.EncodeToString(id.Value())
	ckPriv = s.makeAnRSAKey(c)
	skPriv = s.makeAnRSAKey(c)

	n, err2 := xn.New(name, id, lfs, ckPriv, skPriv, nil, nil, nil)

	c.Assert(err2, IsNil)
	c.Assert(n, Not(IsNil))
	c.Assert(name, Equals, n.GetName())
	actualID := n.GetNodeID()
	c.Assert(true, Equals, id.Equal(actualID))
	// s.doKeyTests(c, n, rng)
	c.Assert(0, Equals, (*n).SizePeers())
	c.Assert(0, Equals, (*n).SizeOverlays())
	c.Assert(0, Equals, n.SizeConnections())
	c.Assert(lfs, Equals, n.GetLFS())
	return n, ckPriv, skPriv
}

func (s *XLSuite) doTestParser(c *C, rng *xr.PRNG) {

	name := s.getAName(rng)
	a := rng.Intn(256)
	b := rng.Intn(256)
	_c := rng.Intn(256)
	d := rng.Intn(256)
	bits := rng.Intn(33)
	aRange := fmt.Sprintf("%d.%d.%d.%d/%d", a, b, _c, d, bits)
	transport := "tcp"
	cost := float32(rng.Intn(300)) / 100.0

	ar, err := NewCIDRAddrRange(aRange)
	c.Assert(err, IsNil)

	o, err := NewIPOverlay(name, ar, transport, cost)
	c.Assert(err, IsNil)
	c.Assert(o, Not(IsNil))

	c.Assert(name, Equals, o.Name())
	// XXX ADDR RANGE MISSING
	c.Assert(transport, Equals, o.Transport())
	c.Assert(float32(cost), Equals, o.Cost())

	text := o.String()
	// DEBUG
	// fmt.Printf("serialized overlay is %s\n", text)
	// END
	o2, err := Parse(text)
	c.Assert(err, IsNil)
	c.Assert(text, Equals, o2.String())
}

// Make a RegCluster for test purposes.  Cluster member names are guaranteed
// to be unique but the name of the cluster itself may not be.
//
// THIS IS THE REGISTRY'S VIEW OF A CLUSTER
func (s *XLSuite) makeARegCluster(c *C, rng *xr.PRNG, epCount, size uint32) (
	rc *RegCluster) {

	var err error
	c.Assert(MIN_CLUSTER_SIZE <= size && size <= MAX_CLUSTER_SIZE, Equals, true)

	attrs := uint64(rng.Int63())
	name := rng.NextFileName(8) // no guarantee of uniqueness
	id := s.makeANodeID(c, rng)

	rc, err = NewRegCluster(name, id, attrs, size, epCount)
	c.Assert(err, IsNil)

	for count := uint32(0); count < size; count++ {
		cm := s.makeAClientInfo(c, rng, epCount)
		for {
			if _, ok := rc.MembersByName[cm.GetName()]; ok {
				// name is in use, so try again
				cm = s.makeAClientInfo(c, rng, epCount)
			} else {
				err = rc.AddMember(cm)
				c.Assert(err, IsNil)
				break
			}
		}
	}
	return
}

func doTestSimpleTreeConstructor(c *C, rng *xr.PRNG, usingSHA1 bool) {
	name := rng.NextFileName(8)
	tree := NewNLHTree(name, usingSHA1)
	c.Assert(tree.name, Equals, name)
	c.Assert(tree.usingSHA1, Equals, usingSHA1)
	c.Assert(len(tree.nodes), Equals, 0)
}

// Return an initialized and tested host, with a NodeID, ckPriv,
// and skPriv.  OpenAcc() is not called and so any acceptors are not open.
func (s *XLSuite) makeHost(c *C, rng *xr.PRNG) *Node {
	// XXX names may not be unique
	name := rng.NextFileName(6)
	for {
		first := string(name[0])
		if !strings.Contains(first, "0123456789") &&
			!strings.Contains(name, "-") {
			break
		}
		name = rng.NextFileName(6)
	}
	id, err := makeNodeID(rng)
	c.Assert(err, Equals, nil)
	c.Assert(id, Not(IsNil))

	lfs := "tmp/" + hex.EncodeToString(id.Value())
	n, err := NewNew(name, id, lfs)
	c.Assert(err, IsNil)
	c.Assert(n, Not(IsNil))
	c.Assert(name, Equals, n.GetName())
	actualID := n.GetNodeID()
	c.Assert(true, Equals, id.Equal(actualID))
	s.doKeyTests(c, n, rng)
	c.Assert(0, Equals, (*n).SizePeers())
	c.Assert(0, Equals, (*n).SizeOverlays())
	c.Assert(0, Equals, n.SizeConnections())
	c.Assert(lfs, Equals, n.GetLFS())
	return n
}

// Make a message (or reply) of up to 16 AES blocks in size and stuff
// it with random bytes.  Return the message with PKCS7-padded appended.
//
func (s *XLSuite) MakeAMsg(c *C, rng *xr.PRNG) (
	msg []byte, msgLen int) {

	msgLen = 2 + rng.Intn(16*aes.BlockSize-2)
	msg = make([]byte, msgLen)
	rng.NextBytes(msg)
	return
}

func doTestConstructor(c *C, rng *xr.PRNG, usingSHA1 bool) {
	name := rng.NextFileName(8)
	b := NewNLHBase(name, usingSHA1)
	c.Assert(b.Name(), Equals, name)
	c.Assert(b.UsingSHA1(), Equals, usingSHA1)
	root := b.Root()
	ct := b.CurTree()
	c.Assert(root.Name(), Equals, ct.Name())
}

func (s *XLSuite) getTwoUniqueDirectoryNames(c *C, rng *xr.PRNG) (
	string, string) {

	dirName1 := rng.NextFileName(MAX_NAME_LEN)
	dirName2 := rng.NextFileName(MAX_NAME_LEN)
	for dirName2 == dirName1 {
		dirName2 = rng.NextFileName(MAX_NAME_LEN)
	}
	return dirName1, dirName2
}

func (s *XLSuite) getAName(rng *xr.PRNG) (name string) {
	name = string(rng.NextFileName(8))
	for {
		first := string(name[0])
		if !strings.ContainsAny(name, "-_.") && !strings.ContainsAny(first, "0123456789") {
			break
		}
		name = string(rng.NextFileName(8))
	}
	return
}

func makeNodeID(rng *xr.PRNG) (*xi.NodeID, error) {
	var buffer []byte
	// quasi-random choice, whether to use an SHA1 or SHA3 nodeID
	if rng.NextBoolean() {
		buffer = make([]byte, xu.SHA1_BIN_LEN)
	} else {
		buffer = make([]byte, xu.SHA3_BIN_LEN)
	}
	rng.NextBytes(buffer)
	return xi.NewNodeID(buffer)
}

func getTwoUniqueDirectoryNames(c *C, rng *xr.PRNG) (dirName1, dirName2 string) {

	dirName1 = rng.NextFileName(8)
	dirName2 = dirName1
	for dirName2 == dirName1 {
		dirName2 = rng.NextFileName(8)
	}
	c.Assert(len(dirName1) > 0, Equals, true)
	c.Assert(len(dirName2) > 0, Equals, true)
	c.Assert(dirName1 != dirName2, Equals, true)
	return
}

func makeOneNamedTestDirectory(c *C, rng *xr.PRNG, name string,
	depth, width int) (dirPath string) {

	dirPath = fmt.Sprintf("tmp/%s", name)
	if _, err := os.Stat(dirPath); err == nil {
		err = os.RemoveAll(dirPath)
		c.Assert(err, IsNil)
	}
	//                                     maxLen, minLen of files (bytes)
	rng.NextDataDir(dirPath, depth, width, 4096, 32)
	return
}

func (s *XLSuite) makeANodeID(c *C, rng *xr.PRNG) (id *NodeID) {
	var length int
	if rng.NextBoolean() {
		length = xu.SHA1_BIN_LEN
	} else {
		length = xu.SHA2_BIN_LEN
	}
	data := make([]byte, length)
	rng.NextBytes(data)
	id, err := New(data)
	c.Assert(err, IsNil)
	return id
}

func makeTwoTestDirectories(c *C, rng *xr.PRNG, depth, width int) (
	dirName1, dirPath1, dirName2, dirPath2 string) {

	dirName1 = rng.NextFileName(8)
	dirPath1 = makeOneNamedTestDirectory(c, rng, dirName1, depth, width)

	dirName2 = dirName1
	for dirName2 == dirName1 {
		dirName2 = rng.NextFileName(8)
	}
	dirPath2 = makeOneNamedTestDirectory(c, rng, dirName2, depth, width)

	return
}

func (s *XLSuite) doTestKeySelector64(c *C, rng *xr.PRNG, usingSHA1 bool, m uint) {

	var v uint     // length of byte array
	if usingSHA1 { //
		v = uint(20) // bytes
	} else {
		v = uint(32)
	}
	b := make([]byte, v)   // value being inserted into filter
	k := uint((v * 8) / m) // number of hash functions

	bitSel := make([]byte, k)
	wordSel := make([]uint, k)
	// 2^6 is 64, number of bits in a uint64
	wordsInFilter := 1 << (m - uint(6))

	for i := uint(0); i < k; i++ {
		bitSel[i] = byte(rng.Intn(64))
		wordSel[i] = uint(rng.Intn(wordsInFilter))
	}

	// concatenate the key selectors at the front
	s.setBitOffsets(c, &b, bitSel)

	// append the word selectors
	s.setWordOffsets(c, &b, wordSel, m, k)

	// create an m,k filter
	filter, err := NewBloomSHA(m, k)
	c.Assert(err, IsNil)

	// verify that the expected bits are NOT set
	for i := uint(0); i < k; i++ {
		filterWord := filter.Filter[wordSel[i]]
		bitSelector := uint64(1) << bitSel[i]
		bitVal := filterWord & bitSelector
		c.Assert(bitVal == 0, Equals, true)
	}

	// insert the value b
	filter.Insert(b)

	// verify that all of the expected bits are set
	for i := uint(0); i < k; i++ {
		filterWord := filter.Filter[wordSel[i]]
		bitSelector := uint64(1) << bitSel[i]
		bitVal := filterWord & bitSelector
		c.Assert(bitVal == 0, Equals, false)
	}
}

func doTestSimpleConstructor(c *C, rng *xr.PRNG, usingSHA1 bool) {

	var sha hash.Hash
	if usingSHA1 {
		sha = sha1.New()
	} else {
		sha = sha256.New()
	}

	name := rng.NextFileName(8)
	n := rng.SomeBytes(8)
	sha.Write(n)
	hash0 := sha.Sum(nil)

	leaf0, err := NewNLHLeaf(name, hash0)
	c.Assert(err, IsNil)
	c.Assert(name, Equals, leaf0.Name())
	c.Assert(hash0, Equals, leaf0.BinHash())

	name2 := name
	for name2 == name {
		name2 = rng.NextFileName(8)
	}
	n = rng.SomeBytes(8)
	sha.Write(n)
	hash1 := sha.Sum(nil)
	leaf1, err := NewNLHLeaf(name2, hash1)
	c.Assert(err, IsNil)
	c.Assert(name2, Equals, leaf1.Name())
	c.Assert(hash1, Equals, leaf1.BinHash())

	c.Assert(leaf0, Equals, leaf0)
	c.Assert(leaf1, Equals, leaf1)
	c.Assert(leaf0.Equal(leaf1), Equals, false)
}

// Populate the K3 byte slices to be used for testing
func (muc *MockUpaxClient) createData(rng *xr.PRNG, K3, L1, L2 int) (
	err error) {

	muc.K3 = K3
	muc.L1 = L1
	muc.L2 = L2

	muc.data = make([][]byte, K3)
	for i := 0; i < K3; i++ {
		length := L1 + rng.Intn(L2-L1+1) // so L1..L2 inclusive
		muc.data[i] = make([]byte, length)
		rng.NextBytes(muc.data[i])
	}
	return
}

func (s *XLSuite) makeAMemberInfo(c *C, rng *xr.PRNG) *xcl.MemberInfo {
	attrs := uint64(rng.Int63())
	peer, err := xn.NewPeer(
		rng.NextFileName(8),
		s.makeANodeID(c, rng),
		&s.makeAnRSAKey(c).PublicKey,
		&s.makeAnRSAKey(c).PublicKey,
		nil, // overlays
		nil) // XXX CONNECTORS
	c.Assert(err, IsNil)
	return &xcl.MemberInfo{
		Attrs: attrs,
		Peer:  peer,
	}
} // GEEP