/*
Copyright IBM Corp. 2016 All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

		 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package crypto

import (
	obc "github.com/hyperledger/fabric/protos"
)

// Public Interfaces

// NodeType represents the node's type
type NodeType int32

const (
	// NodeClient a client
	NodeClient NodeType = 0
	// NodePeer a peer
	NodePeer NodeType = 1
	// NodeValidator a validator
	NodeValidator NodeType = 2
)

// Node represents a crypto object having a name
type Node interface {

	// GetType returns this entity's name
	GetType() NodeType

	// GetName returns this entity's name
	GetName() string
}

// Client is an entity able to deploy and invoke chaincode
type Client interface {
	Node

	// NewChaincodeDeployTransaction is used to deploy chaincode.
	NewChaincodeDeployTransaction(chaincodeDeploymentSpec *obc.ChaincodeDeploymentSpec, uuid string, attributes ...string) (*obc.Transaction, error)

	// NewChaincodeExecute is used to execute chaincode's functions.
	NewChaincodeExecute(chaincodeInvocation *obc.ChaincodeInvocationSpec, uuid string, attributes ...string) (*obc.Transaction, error)

	// NewChaincodeQuery is used to query chaincode's functions.
	NewChaincodeQuery(chaincodeInvocation *obc.ChaincodeInvocationSpec, uuid string, attributes ...string) (*obc.Transaction, error)

	// DecryptQueryResult is used to decrypt the result of a query transaction
	DecryptQueryResult(queryTx *obc.Transaction, result []byte) ([]byte, error)

	// GetEnrollmentCertHandler returns a CertificateHandler whose certificate is the enrollment certificate
	GetEnrollmentCertificateHandler() (CertificateHandler, error)

	// GetTCertHandlerNext returns a CertificateHandler whose certificate is the next available TCert
	GetTCertificateHandlerNext(attributes ...string) (CertificateHandler, error)

	// GetTCertHandlerFromDER returns a CertificateHandler whose certificate is the one passed
	GetTCertificateHandlerFromDER(tCertDER []byte) (CertificateHandler, error)

	// GetNextTCert returns a slice of a requested number of (not yet used) transaction certificates
	GetNextTCerts(nCerts int, attributes ...string) ([]tCert, error)
}

// Peer is an entity able to verify transactions
type Peer interface {
	Node

	// GetID returns this peer's identifier
	GetID() []byte

	// GetEnrollmentID returns this peer's enrollment id
	GetEnrollmentID() string

	// TransactionPreValidation verifies that the transaction is
	// well formed with the respect to the security layer
	// prescriptions (i.e. signature verification).
	TransactionPreValidation(tx *obc.Transaction) (*obc.Transaction, error)

	// TransactionPreExecution verifies that the transaction is
	// well formed with the respect to the security layer
	// prescriptions (i.e. signature verification). If this is the case,
	// the method prepares the transaction to be executed.
	// TransactionPreExecution returns a clone of tx.
	TransactionPreExecution(tx *obc.Transaction) (*obc.Transaction, error)

	// Sign signs msg with this validator's signing key and outputs
	// the signature if no error occurred.
	Sign(msg []byte) ([]byte, error)

	// Verify checks that signature if a valid signature of message under vkID's verification key.
	// If the verification succeeded, Verify returns nil meaning no error occurred.
	// If vkID is nil, then the signature is verified against this validator's verification key.
	Verify(vkID, signature, message []byte) error

	// GetStateEncryptor returns a StateEncryptor linked to pair defined by
	// the deploy transaction and the execute transaction. Notice that,
	// executeTx can also correspond to a deploy transaction.
	GetStateEncryptor(deployTx, executeTx *obc.Transaction) (StateEncryptor, error)

	GetTransactionBinding(tx *obc.Transaction) ([]byte, error)
}

// StateEncryptor is used to encrypt chaincode's state
type StateEncryptor interface {

	// Encrypt encrypts message msg
	Encrypt(msg []byte) ([]byte, error)

	// Decrypt decrypts ciphertext ct obtained
	// from a call of the Encrypt method.
	Decrypt(ct []byte) ([]byte, error)
}

// CertificateHandler exposes methods to deal with an ECert/TCert
type CertificateHandler interface {

	// GetCertificate returns the certificate's DER
	GetCertificate() []byte

	// Sign signs msg using the signing key corresponding to the certificate
	Sign(msg []byte) ([]byte, error)

	// Verify verifies msg using the verifying key corresponding to the certificate
	Verify(signature []byte, msg []byte) error

	// GetTransactionHandler returns a new transaction handler relative to this certificate
	GetTransactionHandler() (TransactionHandler, error)
}

// TransactionHandler represents a single transaction that can be named by the output of the GetBinding method.
// This transaction is linked to a single Certificate (TCert or ECert).
type TransactionHandler interface {

	// GetCertificateHandler returns the certificate handler relative to the certificate mapped to this transaction
	GetCertificateHandler() (CertificateHandler, error)

	// GetBinding returns a binding to the underlying transaction
	GetBinding() ([]byte, error)

	// NewChaincodeDeployTransaction is used to deploy chaincode
	NewChaincodeDeployTransaction(chaincodeDeploymentSpec *obc.ChaincodeDeploymentSpec, uuid string, attributeNames ...string) (*obc.Transaction, error)

	// NewChaincodeExecute is used to execute chaincode's functions
	NewChaincodeExecute(chaincodeInvocation *obc.ChaincodeInvocationSpec, uuid string, attributeNames ...string) (*obc.Transaction, error)

	// NewChaincodeQuery is used to query chaincode's functions
	NewChaincodeQuery(chaincodeInvocation *obc.ChaincodeInvocationSpec, uuid string, attributeNames ...string) (*obc.Transaction, error)
}