/*
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 sanitycheck

import (
	"fmt"

	"github.com/hyperledger/fabric/common/configtx"
	cb "github.com/hyperledger/fabric/protos/common"
	mspprotos "github.com/hyperledger/fabric/protos/msp"
	"github.com/hyperledger/fabric/protos/utils"

	"github.com/golang/protobuf/proto"
)

type Messages struct {
	GeneralErrors   []string          `json:"general_errors"`
	ElementWarnings []*ElementMessage `json:"element_errors"`
	ElementErrors   []*ElementMessage `json:"element_errors"`
}

type ElementMessage struct {
	Path    string `json:"path"`
	Message string `json:"message"`
}

func Check(config *cb.Config) (*Messages, error) {
	envConfig, err := utils.CreateSignedEnvelope(cb.HeaderType_CONFIG, "sanitycheck", nil, &cb.ConfigEnvelope{Config: config}, 0, 0)
	if err != nil {
		return nil, err
	}

	result := &Messages{}

	cm, err := configtx.NewManagerImpl(envConfig, configtx.NewInitializer(), nil)
	if err != nil {
		result.GeneralErrors = []string{err.Error()}
		return result, nil
	}

	// This should come from the MSP manager, but, for some reason
	// the MSP manager is not intialized if there are no orgs, so,
	// we collect this manually.
	mspMap := make(map[string]struct{})

	if ac, ok := cm.ApplicationConfig(); ok {
		for _, org := range ac.Organizations() {
			mspMap[org.MSPID()] = struct{}{}
		}
	}

	if oc, ok := cm.OrdererConfig(); ok {
		for _, org := range oc.Organizations() {
			mspMap[org.MSPID()] = struct{}{}
		}
	}

	policyWarnings, policyErrors := checkPolicyPrincipals(config.ChannelGroup, "", mspMap)

	result.ElementWarnings = policyWarnings
	result.ElementErrors = policyErrors

	return result, nil
}

func checkPolicyPrincipals(group *cb.ConfigGroup, basePath string, mspMap map[string]struct{}) (warnings []*ElementMessage, errors []*ElementMessage) {
	for policyName, configPolicy := range group.Policies {
		appendError := func(err string) {
			errors = append(errors, &ElementMessage{
				Path:    basePath + ".policies." + policyName,
				Message: err,
			})
		}

		appendWarning := func(err string) {
			warnings = append(errors, &ElementMessage{
				Path:    basePath + ".policies." + policyName,
				Message: err,
			})
		}

		if configPolicy.Policy == nil {
			appendError(fmt.Sprintf("no policy value set for %s", policyName))
			continue
		}

		if configPolicy.Policy.Type != int32(cb.Policy_SIGNATURE) {
			continue
		}
		spe := &cb.SignaturePolicyEnvelope{}
		err := proto.Unmarshal(configPolicy.Policy.Value, spe)
		if err != nil {
			appendError(fmt.Sprintf("error unmarshaling policy value to SignaturePolicyEnvelope: %s", err))
			continue
		}

		for i, identity := range spe.Identities {
			var mspID string
			switch identity.PrincipalClassification {
			case mspprotos.MSPPrincipal_ROLE:
				role := &mspprotos.MSPRole{}
				err = proto.Unmarshal(identity.Principal, role)
				if err != nil {
					appendError(fmt.Sprintf("value of identities array at index %d is of type ROLE, but could not be unmarshaled to msp.MSPRole: %s", i, err))
					continue
				}
				mspID = role.MspIdentifier
			case mspprotos.MSPPrincipal_ORGANIZATION_UNIT:
				ou := &mspprotos.OrganizationUnit{}
				err = proto.Unmarshal(identity.Principal, ou)
				if err != nil {
					appendError(fmt.Sprintf("value of identities array at index %d is of type ORGANIZATION_UNIT, but could not be unmarshaled to msp.OrganizationUnit: %s", i, err))
					continue
				}
				mspID = ou.MspIdentifier
			default:
				continue
			}

			_, ok := mspMap[mspID]
			if !ok {
				appendWarning(fmt.Sprintf("identity principal at index %d refers to MSP ID '%s', which is not an MSP in the network", i, mspID))
			}
		}
	}

	for subGroupName, subGroup := range group.Groups {
		subWarnings, subErrors := checkPolicyPrincipals(subGroup, basePath+".groups."+subGroupName, mspMap)
		warnings = append(warnings, subWarnings...)
		errors = append(errors, subErrors...)
	}
	return
}