/*
Copyright IBM Corp. 2017 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 ccprovider

import (
	"fmt"
	"io/ioutil"
	"os"

	"github.com/golang/protobuf/proto"

	"bytes"

	"github.com/hyperledger/fabric/bccsp"
	"github.com/hyperledger/fabric/bccsp/factory"
	"github.com/hyperledger/fabric/core/common/ccpackage"
	"github.com/hyperledger/fabric/protos/common"
	pb "github.com/hyperledger/fabric/protos/peer"
)

//----- SignedCDSData ------

//SignedCDSData is data stored in the LSCC on instantiation of a CC
//for SignedCDSPackage. This needs to be serialized for ChaincodeData
//hence the protobuf format
type SignedCDSData struct {
	CodeHash      []byte `protobuf:"bytes,1,opt,name=hash"`
	MetaDataHash  []byte `protobuf:"bytes,2,opt,name=metadatahash"`
	SignatureHash []byte `protobuf:"bytes,3,opt,name=signaturehash"`
}

//----implement functions needed from proto.Message for proto's mar/unmarshal functions

//Reset resets
func (data *SignedCDSData) Reset() { *data = SignedCDSData{} }

//String converts to string
func (data *SignedCDSData) String() string { return proto.CompactTextString(data) }

//ProtoMessage just exists to make proto happy
func (*SignedCDSData) ProtoMessage() {}

//Equals data equals other
func (data *SignedCDSData) Equals(other *SignedCDSData) bool {
	return other != nil &&
		bytes.Equal(data.CodeHash, other.CodeHash) &&
		bytes.Equal(data.MetaDataHash, other.MetaDataHash) &&
		bytes.Equal(data.SignatureHash, other.SignatureHash)
}

//-------- SignedCDSPackage ---------

//SignedCDSPackage encapsulates SignedChaincodeDeploymentSpec.
type SignedCDSPackage struct {
	buf      []byte
	depSpec  *pb.ChaincodeDeploymentSpec
	sDepSpec *pb.SignedChaincodeDeploymentSpec
	env      *common.Envelope
	data     *SignedCDSData
	datab    []byte
	id       []byte
}

// resets data
func (ccpack *SignedCDSPackage) reset() {
	*ccpack = SignedCDSPackage{}
}

// GetId gets the fingerprint of the chaincode based on package computation
func (ccpack *SignedCDSPackage) GetId() []byte {
	//this has to be after creating a package and initializing it
	//If those steps fail, GetId() should never be called
	if ccpack.id == nil {
		panic("GetId called on uninitialized package")
	}
	return ccpack.id
}

// GetDepSpec gets the ChaincodeDeploymentSpec from the package
func (ccpack *SignedCDSPackage) GetDepSpec() *pb.ChaincodeDeploymentSpec {
	//this has to be after creating a package and initializing it
	//If those steps fail, GetDepSpec() should never be called
	if ccpack.depSpec == nil {
		panic("GetDepSpec called on uninitialized package")
	}
	return ccpack.depSpec
}

// GetInstantiationPolicy gets the instantiation policy from the package
func (ccpack *SignedCDSPackage) GetInstantiationPolicy() []byte {
	if ccpack.sDepSpec == nil {
		panic("GetInstantiationPolicy called on uninitialized package")
	}
	return ccpack.sDepSpec.InstantiationPolicy
}

// GetDepSpecBytes gets the serialized ChaincodeDeploymentSpec from the package
func (ccpack *SignedCDSPackage) GetDepSpecBytes() []byte {
	//this has to be after creating a package and initializing it
	//If those steps fail, GetDepSpecBytes() should never be called
	if ccpack.sDepSpec == nil || ccpack.sDepSpec.ChaincodeDeploymentSpec == nil {
		panic("GetDepSpecBytes called on uninitialized package")
	}
	return ccpack.sDepSpec.ChaincodeDeploymentSpec
}

// GetPackageObject gets the ChaincodeDeploymentSpec as proto.Message
func (ccpack *SignedCDSPackage) GetPackageObject() proto.Message {
	return ccpack.env
}

// GetChaincodeData gets the ChaincodeData
func (ccpack *SignedCDSPackage) GetChaincodeData() *ChaincodeData {
	//this has to be after creating a package and initializing it
	//If those steps fail, GetChaincodeData() should never be called
	if ccpack.depSpec == nil || ccpack.datab == nil || ccpack.id == nil {
		panic("GetChaincodeData called on uninitialized package")
	}

	var instPolicy []byte
	if ccpack.sDepSpec != nil {
		instPolicy = ccpack.sDepSpec.InstantiationPolicy
	}

	return &ChaincodeData{
		Name:                ccpack.depSpec.ChaincodeSpec.ChaincodeId.Name,
		Version:             ccpack.depSpec.ChaincodeSpec.ChaincodeId.Version,
		Data:                ccpack.datab,
		Id:                  ccpack.id,
		InstantiationPolicy: instPolicy,
	}
}

func (ccpack *SignedCDSPackage) getCDSData(scds *pb.SignedChaincodeDeploymentSpec) ([]byte, []byte, *SignedCDSData, error) {
	// check for nil argument. It is an assertion that getCDSData
	// is never called on a package that did not go through/succeed
	// package initialization.
	if scds == nil {
		panic("nil cds")
	}

	cds := &pb.ChaincodeDeploymentSpec{}
	err := proto.Unmarshal(scds.ChaincodeDeploymentSpec, cds)
	if err != nil {
		return nil, nil, nil, err
	}

	if err = factory.InitFactories(nil); err != nil {
		return nil, nil, nil, fmt.Errorf("Internal error, BCCSP could not be initialized : %s", err)
	}

	//get the hash object
	hash, err := factory.GetDefault().GetHash(&bccsp.SHAOpts{})
	if err != nil {
		return nil, nil, nil, err
	}

	scdsdata := &SignedCDSData{}

	//get the code hash
	hash.Write(cds.CodePackage)
	scdsdata.CodeHash = hash.Sum(nil)

	hash.Reset()

	//get the metadata hash
	hash.Write([]byte(cds.ChaincodeSpec.ChaincodeId.Name))
	hash.Write([]byte(cds.ChaincodeSpec.ChaincodeId.Version))

	scdsdata.MetaDataHash = hash.Sum(nil)

	hash.Reset()

	//get the signature hashes
	if scds.InstantiationPolicy == nil {
		return nil, nil, nil, fmt.Errorf("instantiation policy cannot be nil for chaincode (%s:%s)", cds.ChaincodeSpec.ChaincodeId.Name, cds.ChaincodeSpec.ChaincodeId.Version)
	}

	hash.Write(scds.InstantiationPolicy)
	for _, o := range scds.OwnerEndorsements {
		hash.Write(o.Endorser)
	}
	scdsdata.SignatureHash = hash.Sum(nil)

	//marshall data
	b, err := proto.Marshal(scdsdata)
	if err != nil {
		return nil, nil, nil, err
	}

	hash.Reset()

	//compute the id
	hash.Write(scdsdata.CodeHash)
	hash.Write(scdsdata.MetaDataHash)
	hash.Write(scdsdata.SignatureHash)

	id := hash.Sum(nil)

	return b, id, scdsdata, nil
}

// ValidateCC returns error if the chaincode is not found or if its not a
// ChaincodeDeploymentSpec
func (ccpack *SignedCDSPackage) ValidateCC(ccdata *ChaincodeData) error {
	if ccpack.sDepSpec == nil {
		return fmt.Errorf("uninitialized package")
	}

	if ccpack.sDepSpec.ChaincodeDeploymentSpec == nil {
		return fmt.Errorf("signed chaincode deployment spec cannot be nil in a package")
	}

	if ccpack.depSpec == nil {
		return fmt.Errorf("chaincode deployment spec cannot be nil in a package")
	}

	if ccdata.Name != ccpack.depSpec.ChaincodeSpec.ChaincodeId.Name || ccdata.Version != ccpack.depSpec.ChaincodeSpec.ChaincodeId.Version {
		return fmt.Errorf("invalid chaincode data %v (%v)", ccdata, ccpack.depSpec.ChaincodeSpec.ChaincodeId)
	}

	otherdata := &SignedCDSData{}
	err := proto.Unmarshal(ccdata.Data, otherdata)
	if err != nil {
		return err
	}

	if !ccpack.data.Equals(otherdata) {
		return fmt.Errorf("data mismatch")
	}

	return nil
}

//InitFromBuffer sets the buffer if valid and returns ChaincodeData
func (ccpack *SignedCDSPackage) InitFromBuffer(buf []byte) (*ChaincodeData, error) {
	//incase ccpack is reused
	ccpack.reset()

	env := &common.Envelope{}
	err := proto.Unmarshal(buf, env)
	if err != nil {
		return nil, fmt.Errorf("failed to unmarshal envelope from bytes")
	}
	cHdr, sDepSpec, err := ccpackage.ExtractSignedCCDepSpec(env)
	if err != nil {
		return nil, err
	}
	if cHdr.Type != int32(common.HeaderType_CHAINCODE_PACKAGE) {
		return nil, fmt.Errorf("invalid type of envelope for chaincode package")
	}

	depSpec := &pb.ChaincodeDeploymentSpec{}
	err = proto.Unmarshal(sDepSpec.ChaincodeDeploymentSpec, depSpec)
	if err != nil {
		return nil, fmt.Errorf("error getting deployment spec")
	}

	databytes, id, data, err := ccpack.getCDSData(sDepSpec)
	if err != nil {
		return nil, err
	}

	ccpack.buf = buf
	ccpack.sDepSpec = sDepSpec
	ccpack.depSpec = depSpec
	ccpack.env = env
	ccpack.data = data
	ccpack.datab = databytes
	ccpack.id = id

	return ccpack.GetChaincodeData(), nil
}

//InitFromFS returns the chaincode and its package from the file system
func (ccpack *SignedCDSPackage) InitFromFS(ccname string, ccversion string) ([]byte, *pb.ChaincodeDeploymentSpec, error) {
	//incase ccpack is reused
	ccpack.reset()

	buf, err := GetChaincodePackage(ccname, ccversion)
	if err != nil {
		return nil, nil, err
	}

	if _, err = ccpack.InitFromBuffer(buf); err != nil {
		return nil, nil, err
	}

	return ccpack.buf, ccpack.depSpec, nil
}

//PutChaincodeToFS - serializes chaincode to a package on the file system
func (ccpack *SignedCDSPackage) PutChaincodeToFS() error {
	if ccpack.buf == nil {
		return fmt.Errorf("uninitialized package")
	}

	if ccpack.id == nil {
		return fmt.Errorf("id cannot be nil if buf is not nil")
	}

	if ccpack.sDepSpec == nil || ccpack.depSpec == nil {
		return fmt.Errorf("depspec cannot be nil if buf is not nil")
	}

	if ccpack.env == nil {
		return fmt.Errorf("env cannot be nil if buf and depspec are not nil")
	}

	if ccpack.data == nil {
		return fmt.Errorf("nil data")
	}

	if ccpack.datab == nil {
		return fmt.Errorf("nil data bytes")
	}

	ccname := ccpack.depSpec.ChaincodeSpec.ChaincodeId.Name
	ccversion := ccpack.depSpec.ChaincodeSpec.ChaincodeId.Version

	//return error if chaincode exists
	path := fmt.Sprintf("%s/%s.%s", chaincodeInstallPath, ccname, ccversion)
	if _, err := os.Stat(path); err == nil {
		return fmt.Errorf("chaincode %s exists", path)
	}

	if err := ioutil.WriteFile(path, ccpack.buf, 0644); err != nil {
		return err
	}

	return nil
}