// create handling the creation of a new character
// curl -H "Content-Type: application/json" -X POST -d '{"name":"asdf"}' http://localhost:8989
func create(c *gin.Context) {

	var newName struct {
		Name string `json:"name"`
	}
	ch := NewCharacter{}

	if err := c.BindJSON(&newName); err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{"error while binding newName:" + err.Error()})
		return
	}

	checkSum := sha1.Sum([]byte(newName.Name))
	ch.CharacterID = fmt.Sprintf("%x", checkSum)

	char := createCharacter(ch.CharacterID, newName.Name)

	log.Println("Saving character:", char)
	err := mdb.Save(char)
	if err != nil {
		c.JSON(http.StatusBadRequest, ErrorResponse{"error while saving character:" + err.Error()})
		return
	}
	c.JSON(http.StatusCreated, char)
}

func ProcessAccountOverviewPassword(res http.ResponseWriter, req *http.Request, base *BaseController) {
	new_password := req.PostFormValue("newpassword")
	old_password := req.PostFormValue("oldpassword")
	if len(new_password) > 30 || len(new_password) < 5 {
		base.Session.SetFlash("Your password should have between 5 - 30 characters!", "error")
		http.Redirect(res, req, "/account/manage/overview/password", 301)
		return
	}
	if new_password != req.PostFormValue("newpassword2") {
		base.Session.SetFlash("The new passwords do not match!", "error")
		http.Redirect(res, req, "/account/manage/overview/password", 301)
		return
	}
	old_password_sha1 := fmt.Sprintf("%x", sha1.Sum([]byte(old_password)))
	if old_password_sha1 != base.Account.Password {
		base.Session.SetFlash("Current password is not correct", "error")
		http.Redirect(res, req, "/account/manage/overview/password", 301)
		return
	}
	err := models.ChangeAccountPassword(base.Account.Id, fmt.Sprintf("%x", sha1.Sum([]byte(new_password))))
	if err != nil {
		http.Error(res, "Error while trying to change password", 500)
		return
	}
	views.Parser.ExecuteTemplate(res, "account_overview_password_success.html", &AccountOverviewPasswordSuccessResponse{"account-manage"})
}

func (c *keyManagementContext) calculateDHSessionKeys(ourKeyID, theirKeyID uint32) (sessionKeys, error) {
	var ret sessionKeys
	var sendbyte, recvbyte byte

	ourPrivKey, ourPubKey, err := c.pickOurKeys(ourKeyID)
	if err != nil {
		return ret, err
	}

	theirPubKey, err := c.pickTheirKey(theirKeyID)
	if err != nil {
		return ret, err
	}

	if gt(ourPubKey, theirPubKey) {
		//we are high end
		sendbyte, recvbyte = 0x01, 0x02
	} else {
		//we are low end
		sendbyte, recvbyte = 0x02, 0x01
	}

	s := new(big.Int).Exp(theirPubKey, ourPrivKey, p)
	secbytes := appendMPI(nil, s)

	sha := sha1.New()
	copy(ret.sendingAESKey[:], h(sendbyte, secbytes, sha))
	copy(ret.receivingAESKey[:], h(recvbyte, secbytes, sha))

	ret.sendingMACKey = sha1.Sum(ret.sendingAESKey[:])
	ret.receivingMACKey = sha1.Sum(ret.receivingAESKey[:])

	c.macKeyHistory.addKeys(ourKeyID, theirKeyID, ret.sendingMACKey, ret.receivingMACKey)
	return ret, nil
}

// KeyVerify verifies that a key certification request was genuinely
// provided by the TPM. It takes the certification data, certification
// validation blob, the public half of the AIK, the public half of the key
// to be certified and the nonce used in the original quote request. It then
// verifies that the validation block is a valid signature for the
// certification data, that the certification data matches the certified key
// and that the secrets are the same (in order to avoid replay attacks). It
// returns an error if any stage of the validation fails.
func KeyVerify(data []byte, validation []byte, aikpub []byte, keypub []byte, secret []byte) error {
	n := big.NewInt(0)
	n.SetBytes(aikpub)
	e := 65537

	pKey := rsa.PublicKey{N: n, E: int(e)}

	dataHash := sha1.Sum(data[:])

	err := rsa.VerifyPKCS1v15(&pKey, crypto.SHA1, dataHash[:], validation)
	if err != nil {
		return err
	}

	keyHash := data[43:63]
	nonceHash := data[63:83]

	secretHash := sha1.Sum(secret[:])

	if bytes.Equal(secretHash[:], nonceHash) == false {
		return fmt.Errorf("Secret doesn't match")
	}

	certHash := sha1.Sum(keypub[:])

	if bytes.Equal(certHash[:], keyHash) == false {
		return fmt.Errorf("Key doesn't match")
	}

	return nil
}

func scramble(encoded_salt, pass string) (scramble []byte, err error) {
	/* ==================================================================
		According to: http://tarantool.org/doc/dev_guide/box-protocol.html

		salt = base64_decode(encoded_salt);
		step_1 = sha1(password);
		step_2 = sha1(step_1);
		step_3 = sha1(salt, step_2);
		scramble = xor(step_1, step_3);
		return scramble;

	===================================================================== */
	scrambleSize := sha1.Size // == 20

	salt, err := base64.StdEncoding.DecodeString(encoded_salt)
	if err != nil {
		return
	}
	step_1 := sha1.Sum([]byte(pass))
	step_2 := sha1.Sum(step_1[0:])
	hash := sha1.New() // may be create it once per connection ?
	hash.Write(salt[0:scrambleSize])
	hash.Write(step_2[0:])
	step_3 := hash.Sum(nil)

	return xor(step_1[0:], step_3[0:], scrambleSize), nil
}

func calculateDHSessionKeys(ourPrivKey, ourPubKey, theirPubKey *big.Int) sessionKeys {
	var ret sessionKeys
	var sendbyte, recvbyte byte

	if gt(ourPubKey, theirPubKey) {
		//we are high end
		sendbyte, recvbyte = 0x01, 0x02
	} else {
		//we are low end
		sendbyte, recvbyte = 0x02, 0x01
	}

	s := new(big.Int).Exp(theirPubKey, ourPrivKey, p)
	secbytes := appendMPI(nil, s)

	sha := sha1.New()
	copy(ret.sendingAESKey[:], h(sendbyte, secbytes, sha))
	copy(ret.receivingAESKey[:], h(recvbyte, secbytes, sha))

	ret.sendingMACKey = sha1.Sum(ret.sendingAESKey[:])
	ret.receivingMACKey = sha1.Sum(ret.receivingAESKey[:])

	copy(ret.extraKey[:], h(0xFF, secbytes, sha256.New()))

	return ret
}

// QuoteVerify verifies that a quote was genuinely provided by the TPM. It
// takes the quote data, quote validation blob, public half of the AIK,
// current PCR values and the nonce used in the original quote request. It
// then verifies that the validation block is a valid signature for the
// quote data, that the secrets are the same (in order to avoid replay
// attacks), and that the PCR values are the same. It returns an error if
// any stage of the validation fails.
func QuoteVerify(data []byte, validation []byte, aikpub []byte, pcrvalues [][]byte, secret []byte) error {
	n := big.NewInt(0)
	n.SetBytes(aikpub)
	e := 65537

	pKey := rsa.PublicKey{N: n, E: int(e)}

	dataHash := sha1.Sum(data[:])

	err := rsa.VerifyPKCS1v15(&pKey, crypto.SHA1, dataHash[:], validation)
	if err != nil {
		return err
	}

	pcrHash := data[8:28]
	nonceHash := data[28:48]

	secretHash := sha1.Sum(secret[:])

	if bytes.Equal(secretHash[:], nonceHash) == false {
		return fmt.Errorf("Secret doesn't match")
	}

	pcrComposite := []byte{0x00, 0x02, 0xff, 0xff, 0x00, 0x00, 0x01, 0x40}
	for i := 0; i < 16; i++ {
		pcrComposite = append(pcrComposite, pcrvalues[i]...)
	}
	pcrCompositeHash := sha1.Sum(pcrComposite[:])

	if bytes.Equal(pcrCompositeHash[:], pcrHash) == false {
		return fmt.Errorf("PCR values don't match")
	}

	return nil
}

func SaltedHash(pw, saltSeed string) Key {
	hashedPw := sha1.Sum([]byte(pw))
	sha := sha1.New()
	hashedSalt := sha1.Sum([]byte(saltSeed))
	io.WriteString(sha, hex.EncodeToString(hashedSalt[:]))
	io.WriteString(sha, hex.EncodeToString(hashedPw[:]))
	return Key(hex.EncodeToString(sha.Sum(nil)[:]))
}

func HashedAndSalt(pw, saltSeed string) (Hash, Salt) {
	hashedPw := sha1.Sum([]byte(pw))
	sha := sha1.New()
	hashedSalt := sha1.Sum([]byte(saltSeed))
	io.WriteString(sha, hex.EncodeToString(hashedSalt[:]))
	io.WriteString(sha, hex.EncodeToString(hashedPw[:]))
	return Hash(hex.EncodeToString(sha.Sum(nil)[:])),
		Salt(hex.EncodeToString(hashedSalt[:]))
}

func (b *BS) Put(key string, blob io.Reader) (string, error) {
	if key == "" {
		for i := 0; i < 1<<10; i++ {
			p := make([]byte, 16)
			_, err := rand.Read(p)
			if err != nil {
				return "", err
			}
			key = hex.EncodeToString(p)

			sum := sha1.Sum([]byte(key))
			name := hex.EncodeToString(sum[:])

			err = os.MkdirAll(filepath.Join(b.path, name[:2]), 0766)
			if err != nil {
				return "", err
			}

			f, err := os.OpenFile(filepath.Join(b.path, name[:2], name), os.O_CREATE|os.O_EXCL, 0666)
			if err != nil {
				if os.IsExist(err) {
					continue
				}
				return "", err
			}
			err = f.Close()
			if err != nil {
				return "", err
			}

			break
		}
	}

	sum := sha1.Sum([]byte(key))
	name := hex.EncodeToString(sum[:])

	err := os.MkdirAll(filepath.Join(b.path, name[:2]), 0766)
	if err != nil {
		return "", err
	}

	f, err := os.Create(filepath.Join(b.path, name[:2], name))
	if err != nil {
		return "", err
	}
	_, err = io.Copy(f, blob)
	if err != nil {
		return "", err
	}
	err = f.Close()
	if err != nil {
		return "", err
	}
	return key, nil
}

//hash is the hashed secret sent over the wire
func getShare(hash string) (share, error) {
	for secret, s := range shares {
		fmt.Printf("%s\n", hash)
		fmt.Printf("%s\n", sha1.Sum([]byte(secret)))
		if hash == fmt.Sprintf("%s", sha1.Sum([]byte(secret))) {
			return s, nil
		}
	}
	return share{}, fmt.Errorf("Not a common share")
}

// Extracts the value (the part of the string before the '.') from val. 'Valid' is true
// if the signature is valid, otherwise false.
func Unsign(val string, secret string) (str string, valid bool) {
	str = strings.Split(val, ".")[0]
	signed := Sign(str, secret)

	// In certain cases, information can be leaked by using a timing attack.
	// It takes advantage of the == operator only comparing until it finds a difference in the two strings. To prevent it,
	// hash both hashed strings first - this doesn't stop the timing difference, but it makes the information useless.
	valid = sha1.Sum([]byte(signed)) == sha1.Sum([]byte(val))
	return
}

func TestCachedFileStoreRead(t *testing.T) {
	rcp := NewRamCacheProvider(2000)
	for _, testFile := range tests {
		fs, err := mkFileStore(testFile)
		orig, _ := ioutil.ReadFile(testFile.path)
		numPieces := len(orig) / 512
		if len(orig)%512 > 0 {
			numPieces++
		}
		tC := rcp.NewCache("test", numPieces, 512, int64(len(orig)), fs)
		tC.WritePiece(orig[:512], 0)
		tC.WritePiece(orig[512:1024], 1)

		if err != nil {
			t.Fatal(err)
		}
		ret := make([]byte, testFile.fileLen)
		_, err = tC.ReadAt(ret, 0)
		if err != nil {
			t.Fatal(err)
		}
		wantedsum := sha1.Sum(orig[:testFile.fileLen])
		sum1Str := hex.EncodeToString(wantedsum[0:])
		gotsum := sha1.Sum(ret)
		sum2Str := hex.EncodeToString(gotsum[0:])
		if sum1Str != sum2Str {
			t.Errorf("Wanted %v, got %v\n on cache read", sum1Str, sum2Str)
			for i := 0; i < len(ret); i++ {
				if ret[i] != orig[i] {
					log.Println("Found a difference at", i, "wanted", orig[i], "got", ret[i])
					break
				}
			}
		}

		ret = make([]byte, testFile.fileLen)
		_, err = fs.ReadAt(ret, 0)
		if err != nil {
			t.Fatal(err)
		}
		gotsum = sha1.Sum(ret)
		sum2Str = hex.EncodeToString(gotsum[0:])
		if sum1Str != sum2Str {
			t.Errorf("Wanted %v, got %v\n on filestore read", sum1Str, sum2Str)
			for i := 0; i < len(ret); i++ {
				if ret[i] != orig[i] {
					log.Println("Found a difference at", i, "wanted", orig[i], "got", ret[i])
					break
				}
			}
		}

		fs.Close()
	}
}

func constantTimeEquals(a string, b string) bool {
	// compare SHA-1 as a gatekeeper in constant time
	// then check that we didn't get by because of a collision
	aSha := sha1.Sum([]byte(a))
	bSha := sha1.Sum([]byte(b))
	if subtle.ConstantTimeCompare(aSha[:], bSha[:]) == 1 {
		// yes, this bit isn't constant, but you had to make a Sha1 collision to get here
		return a == b
	}
	return false
}

func (s *share) createPing(secret string) []byte {
	buf := bytes.NewBuffer([]byte("DBIT"))
	err := bencode.Marshal(buf, Header{
		"ping",
		*port,
		fmt.Sprintf("%s", sha1.Sum([]byte(secret))),
		fmt.Sprintf("%s", sha1.Sum([]byte("192.168.1.64:6667"))),
	})
	check(err)

	return buf.Bytes()
}

func (t *mytree) insert(pair kv) {
	p := t.root
	pf := p

	kb := []byte(pair.key)
	h := hasher.Sum(kb)
	bit := uint(0)
	var idn uint

	for p != nil {
		if p.kv != nil {
			break
		}
		idn = ((uint(h[(bit)>>3])) >> (bit & 7)) & FILTER
		pf = p
		p = p.next[idn]
		bit += BIT
	}
	if p != nil {
		if p.kv.key == pair.key {
			p.kv.value = pair.value
			return
		}
		kvp := p.kv
		p.kv = nil
		kvpb := []byte(kvp.key)
		hash0 := hasher.Sum(kvpb)
		var idn0 uint
		for {
			idn0 = ((uint(hash0[(bit)>>3])) >> (bit & 7)) & FILTER
			idn = ((uint(h[(bit)>>3])) >> (bit & 7)) & FILTER
			if idn == idn0 {
				nn := t.NewNode()
				p.next[idn] = nn
				p = nn
			} else {
				nn := t.NewNode()
				nn.kv = &pair
				nn0 := t.NewNode()
				nn0.kv = kvp
				p.next[idn0] = nn0
				p.next[idn] = nn
				return
			}
			bit += BIT
		}
	} else {
		nn := t.NewNode()
		nn.kv = &pair
		pf.next[idn] = nn
	}
}

func (s *share) createRequest(path string, index, begin, length int) []byte {
	b := bytes.NewBuffer([]byte("DBIT"))
	err := bencode.Marshal(b, Request{
		"req",
		*port,
		fmt.Sprintf("%s", sha1.Sum([]byte(s.Secret))),
		fmt.Sprintf("%s", sha1.Sum([]byte("192.168.1.64:6667"))),
		path,
		index,
		begin,
		length,
	})
	check(err)
	return b.Bytes()
}

func normalizeCert(cert interface{}) string {
	if cert == nil {
		return ""
	}
	switch cert.(type) {
	case string:
		hash := sha1.Sum([]byte(strings.TrimSpace(cert.(string))))
		return hex.EncodeToString(hash[:])
	case *string:
		hash := sha1.Sum([]byte(strings.TrimSpace(*cert.(*string))))
		return hex.EncodeToString(hash[:])
	default:
		return ""
	}
}

func (s *share) createPiece(path string, index, begin int, piece []byte) []byte {
	b := bytes.NewBuffer([]byte("DBIT"))
	err := bencode.Marshal(b, Piece{
		"piece",
		*port,
		fmt.Sprintf("%s", sha1.Sum([]byte(s.Secret))),
		fmt.Sprintf("%s", sha1.Sum([]byte("192.168.1.64:6667"))),
		path,
		index,
		begin,
		fmt.Sprintf("%s", piece),
	})
	check(err)
	return b.Bytes()
}

func main() {
	var blobname = flag.String("blob", "aikblob", "The name of the file to create")
	var tpmname = flag.String("tpm", "/dev/tpm0", "The path to the TPM device to use")
	flag.Parse()

	f, err := os.OpenFile(*tpmname, os.O_RDWR, 0600)
	defer f.Close()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Couldn't open TPM device %s: %s\n", *tpmname, err)
		return
	}

	// Compute the auth values as needed.
	var ownerAuth [20]byte
	ownerInput := os.Getenv(ownerAuthEnvVar)
	if ownerInput != "" {
		oa := sha1.Sum([]byte(ownerInput))
		copy(ownerAuth[:], oa[:])
	}

	var srkAuth [20]byte
	srkInput := os.Getenv(srkAuthEnvVar)
	if srkInput != "" {
		sa := sha1.Sum([]byte(srkInput))
		copy(srkAuth[:], sa[:])
	}

	var aikAuth [20]byte
	aikInput := os.Getenv(aikAuthEnvVar)
	if aikInput != "" {
		aa := sha1.Sum([]byte(aikInput))
		copy(aikAuth[:], aa[:])
	}

	// TODO(tmroeder): add support for Privacy CAs.
	blob, err := tpm.MakeIdentity(f, srkAuth[:], ownerAuth[:], aikAuth[:], nil, nil)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Couldn't make an new AIK: %s\n", err)
		return
	}

	if err := ioutil.WriteFile(*blobname, blob, 0600); err != nil {
		fmt.Fprintf(os.Stderr, "Couldn't write to file %s: %s\n", *blobname, err)
		return
	}

	return
}