/*
Copyright IBM Corp. 2016-2019 All Rights Reserved.

SPDX-License-Identifier: Apache-2.0
*/

package ccpackage

import (
	"bytes"
	"errors"
	"fmt"

	"github.com/golang/protobuf/proto"
	"github.com/hyperledger/fabric/internal/pkg/identity"
	"github.com/hyperledger/fabric/protos/common"
	"github.com/hyperledger/fabric/protos/peer"
	"github.com/hyperledger/fabric/protoutil"
)

// ExtractSignedCCDepSpec extracts the messages from the envelope
func ExtractSignedCCDepSpec(env *common.Envelope) (*common.ChannelHeader, *peer.SignedChaincodeDeploymentSpec, error) {
	p := &common.Payload{}
	err := proto.Unmarshal(env.Payload, p)
	if err != nil {
		return nil, nil, err
	}
	if p.Header == nil {
		return nil, nil, errors.New("channel header cannot be nil")
	}
	ch := &common.ChannelHeader{}
	err = proto.Unmarshal(p.Header.ChannelHeader, ch)
	if err != nil {
		return nil, nil, err
	}

	sp := &peer.SignedChaincodeDeploymentSpec{}
	err = proto.Unmarshal(p.Data, sp)
	if err != nil {
		return nil, nil, err
	}

	return ch, sp, nil
}

// This file provides functions for helping with the chaincode install
// package workflow. In particular
//     OwnerCreateSignedCCDepSpec - each owner creates signs the package using the same deploy
//     CreateSignedCCDepSpecForInstall - an admin or owner creates the package to be installed
//                                       using the packages from OwnerCreateSignedCCDepSpec

// ValidateCip validate the endorsed package against the base package
func ValidateCip(baseCip, otherCip *peer.SignedChaincodeDeploymentSpec) error {
	if baseCip == nil || otherCip == nil {
		panic("do not call with nil parameters")
	}

	if (baseCip.OwnerEndorsements == nil && otherCip.OwnerEndorsements != nil) || (baseCip.OwnerEndorsements != nil && otherCip.OwnerEndorsements == nil) {
		return fmt.Errorf("endorsements should either be both nil or not nil")
	}

	bN := len(baseCip.OwnerEndorsements)
	oN := len(otherCip.OwnerEndorsements)
	if bN > 1 || oN > 1 {
		return fmt.Errorf("expect utmost 1 endorsement from a owner")
	}

	if bN != oN {
		return fmt.Errorf("Rule-all packages should be endorsed or none should be endorsed failed for (%d, %d)", bN, oN)
	}

	if !bytes.Equal(baseCip.ChaincodeDeploymentSpec, otherCip.ChaincodeDeploymentSpec) {
		return fmt.Errorf("Rule-all deployment specs should match(%d, %d)", len(baseCip.ChaincodeDeploymentSpec), len(otherCip.ChaincodeDeploymentSpec))
	}

	if !bytes.Equal(baseCip.InstantiationPolicy, otherCip.InstantiationPolicy) {
		return fmt.Errorf("Rule-all instantiation policies should match(%d, %d)", len(baseCip.InstantiationPolicy), len(otherCip.InstantiationPolicy))
	}

	return nil
}

func createSignedCCDepSpec(cdsbytes []byte, instpolicybytes []byte, endorsements []*peer.Endorsement) (*common.Envelope, error) {
	if cdsbytes == nil {
		return nil, fmt.Errorf("nil chaincode deployment spec")
	}

	if instpolicybytes == nil {
		return nil, fmt.Errorf("nil instantiation policy")
	}

	// create SignedChaincodeDeploymentSpec...
	cip := &peer.SignedChaincodeDeploymentSpec{ChaincodeDeploymentSpec: cdsbytes, InstantiationPolicy: instpolicybytes, OwnerEndorsements: endorsements}

	//...and marshal it
	cipbytes := protoutil.MarshalOrPanic(cip)

	//use defaults (this is definitely ok for install package)
	msgVersion := int32(0)
	epoch := uint64(0)
	chdr := protoutil.MakeChannelHeader(common.HeaderType_CHAINCODE_PACKAGE, msgVersion, "", epoch)

	// create the payload
	payl := &common.Payload{Header: &common.Header{ChannelHeader: protoutil.MarshalOrPanic(chdr)}, Data: cipbytes}
	paylBytes, err := protoutil.GetBytesPayload(payl)
	if err != nil {
		return nil, err
	}

	// here's the unsigned  envelope. The install package is endorsed if signingEntity != nil
	return &common.Envelope{Payload: paylBytes}, nil
}

// CreateSignedCCDepSpecForInstall creates the final package from a set of packages signed by
// owners.  This is similar to how the SDK assembles a TX from various proposal
// responses from the signatures.
func CreateSignedCCDepSpecForInstall(pack []*common.Envelope) (*common.Envelope, error) {
	if len(pack) == 0 {
		return nil, errors.New("no packages provided to collate")
	}

	//rules...
	//   all packages must be endorsed or all packages should not be endorsed
	//   the chaincode deployment spec should be same
	var baseCip *peer.SignedChaincodeDeploymentSpec
	var err error
	var endorsementExists bool
	var endorsements []*peer.Endorsement
	for n, r := range pack {
		p := &common.Payload{}
		if err = proto.Unmarshal(r.Payload, p); err != nil {
			return nil, err
		}

		cip := &peer.SignedChaincodeDeploymentSpec{}
		if err = proto.Unmarshal(p.Data, cip); err != nil {
			return nil, err
		}

		//if its the first element, check if it has endorsement so we can
		//enforce endorsement rules
		if n == 0 {
			baseCip = cip
			//if it has endorsement, all other owners should have signed too
			if len(cip.OwnerEndorsements) > 0 {
				endorsementExists = true
				endorsements = make([]*peer.Endorsement, len(pack))
			}

		} else if err = ValidateCip(baseCip, cip); err != nil {
			return nil, err
		}

		if endorsementExists {
			endorsements[n] = cip.OwnerEndorsements[0]
		}
	}

	return createSignedCCDepSpec(baseCip.ChaincodeDeploymentSpec, baseCip.InstantiationPolicy, endorsements)
}

// OwnerCreateSignedCCDepSpec creates a package from a ChaincodeDeploymentSpec and
// optionally endorses it
func OwnerCreateSignedCCDepSpec(cds *peer.ChaincodeDeploymentSpec, instPolicy *common.SignaturePolicyEnvelope, owner identity.SignerSerializer) (*common.Envelope, error) {
	if cds == nil {
		return nil, fmt.Errorf("invalid chaincode deployment spec")
	}

	if instPolicy == nil {
		return nil, fmt.Errorf("must provide an instantiation policy")
	}

	cdsbytes := protoutil.MarshalOrPanic(cds)

	instpolicybytes := protoutil.MarshalOrPanic(instPolicy)

	var endorsements []*peer.Endorsement
	//it is not mandatory (at this protoutil level) to have a signature
	//this is especially convenient during dev/test
	//it may be necessary to enforce it via a policy at a higher level
	if owner != nil {
		// serialize the signing identity
		endorser, err := owner.Serialize()
		if err != nil {
			return nil, fmt.Errorf("Could not serialize the signing identity: %s", err)
		}

		// sign the concatenation of cds, instpolicy and the serialized endorser identity with this endorser's key
		signature, err := owner.Sign(append(cdsbytes, append(instpolicybytes, endorser...)...))
		if err != nil {
			return nil, fmt.Errorf("Could not sign the ccpackage, err %s", err)
		}

		// each owner starts off the endorsements with one element. All such endorsed
		// packages will be collected in a final package by CreateSignedCCDepSpecForInstall
		// when endorsements will have all the entries
		endorsements = make([]*peer.Endorsement, 1)

		endorsements[0] = &peer.Endorsement{Signature: signature, Endorser: endorser}
	}

	return createSignedCCDepSpec(cdsbytes, instpolicybytes, endorsements)
}

// SignExistingPackage adds a signature to a signed package.
func SignExistingPackage(env *common.Envelope, owner identity.SignerSerializer) (*common.Envelope, error) {
	if owner == nil {
		return nil, fmt.Errorf("owner not provided")
	}

	ch, sdepspec, err := ExtractSignedCCDepSpec(env)
	if err != nil {
		return nil, err
	}

	if ch == nil {
		return nil, fmt.Errorf("channel header not found in the envelope")
	}

	if sdepspec == nil || sdepspec.ChaincodeDeploymentSpec == nil || sdepspec.InstantiationPolicy == nil || sdepspec.OwnerEndorsements == nil {
		return nil, fmt.Errorf("invalid signed deployment spec")
	}

	// serialize the signing identity
	endorser, err := owner.Serialize()
	if err != nil {
		return nil, fmt.Errorf("Could not serialize the signing identity: %s", err)
	}

	// sign the concatenation of cds, instpolicy and the serialized endorser identity with this endorser's key
	signature, err := owner.Sign(append(sdepspec.ChaincodeDeploymentSpec, append(sdepspec.InstantiationPolicy, endorser...)...))
	if err != nil {
		return nil, fmt.Errorf("Could not sign the ccpackage, err %s", err)
	}

	endorsements := append(sdepspec.OwnerEndorsements, &peer.Endorsement{Signature: signature, Endorser: endorser})

	return createSignedCCDepSpec(sdepspec.ChaincodeDeploymentSpec, sdepspec.InstantiationPolicy, endorsements)
}