// alterPublication will maliciously alter a publications information.
// It returns true if the publication was altered.
// It takes as input the publication.
func (b *Broker) alterPublication(pub *pb.Publication) pb.Publication {
	tempPub := pb.Publication{
		PubType:       pub.PubType,
		PublisherID:   pub.PublisherID,
		PublicationID: pub.PublicationID,
		TopicID:       pub.TopicID,
		BrokerID:      pub.BrokerID,
	}

	for i := range pub.Contents {
		tempPub.Contents = append(tempPub.Contents, pub.Contents[i])
	}
	for i := range pub.ChainMACs {
		tempPub.ChainMACs = append(tempPub.ChainMACs, pub.ChainMACs[i])
	}

	r := b.random.Intn(101)

	if r <= b.maliciousPercent {
		var alterType int

		if len(tempPub.ChainMACs) > 0 {
			alterType = r % 6
		} else {
			alterType = r % 5
		}
		switch alterType {
		case 0:
			tempPub.PublicationID = tempPub.PublicationID + 1
		case 1:
			tempPub.PublisherID = tempPub.PublisherID + 1
		case 2:
			tempPub.BrokerID = tempPub.BrokerID + 1
		case 3:
			tempPub.TopicID = tempPub.TopicID + 1
		case 4:
			if len(tempPub.Contents) > 0 {
				tempPub.Contents[0] = badMessage
			}
		case 5:
			tempPub.ChainMACs = nil
		}
	}

	return tempPub
}
// addMACsRecursive adds MACs to the chain of MACs. Some older MACs may need to be kept depending
// on the number of generations in the chain.
// It takes as input the new publication,
// the old publication,
// the current node ID string in the tree (should start with the local node's children),
// and the number of generations to add.
func (b *Broker) addMACsRecursive(pub *pb.Publication, oldPub *pb.Publication, currentStr string, generations uint64) {
	// Add any old chain MACs that add going to the child node
	for _, oldChainMAC := range oldPub.ChainMACs {
		if oldChainMAC.To == currentStr {
			pub.ChainMACs = append(pub.ChainMACs, oldChainMAC)
		}
	}

	if generations > 1 {
		// Add MACs for all the broker children
		for _, childStr := range b.chainNodes[currentStr].children {
			addMAC := true

			// Check if the subscriber is subscribed to this topic
			if strings.HasPrefix(childStr, "S") {
				childID, _ := strconv.ParseUint(childStr[1:], 10, 64)
				b.subscribersMutex.RLock()
				if b.subscribers[childID].topics[pub.TopicID] == false {
					// Don't add the MAC is the subscriber isn't interested in this topic
					addMAC = false
				}
				b.subscribersMutex.RUnlock()
			}

			if addMAC {
				chainMAC := pb.ChainMAC{
					From: b.localStr,
					To:   childStr,
					MAC:  common.CreatePublicationMAC(pub, b.chainNodes[childStr].key),
				}

				pub.ChainMACs = append(pub.ChainMACs, &chainMAC)

				// Recursively add child macs for next generation
				b.addMACsRecursive(pub, oldPub, childStr, generations-1)
			}
		}
	}
}
// addMACsRecursive adds MACs to the chain of MACs.
// It takes as input the publication,
// the current node ID string in the tree (should start with the local node's children),
// and the number of generations to add.
func (p *Publisher) addMACs(pub *pb.Publication, currentStr string, generations uint64) {
	if generations > 1 {
		// Add MACs for all the children
		for _, childStr := range p.chainNodes[currentStr].children {
			chainMAC := pb.ChainMAC{
				From: p.localStr,
				To:   childStr,
				MAC:  common.CreatePublicationMAC(pub, p.chainNodes[childStr].key),
			}

			pub.ChainMACs = append(pub.ChainMACs, &chainMAC)

			// Recursively add child macs for next generation
			p.addMACs(pub, childStr, generations-1)
		}
	}
}