/*
Copyright IBM Corp. All Rights Reserved.

SPDX-License-Identifier: Apache-2.0
*/

package kafka

import (
	"github.com/Shopify/sarama"
	"github.com/hyperledger/fabric-lib-go/healthz"
	cb "github.com/hyperledger/fabric-protos-go/common"
	"github.com/hyperledger/fabric/common/flogging"
	"github.com/hyperledger/fabric/common/metrics"
	"github.com/hyperledger/fabric/orderer/common/localconfig"
	"github.com/hyperledger/fabric/orderer/consensus"
	"github.com/hyperledger/fabric/orderer/consensus/inactive"
	"github.com/pkg/errors"
)

//go:generate counterfeiter -o mock/health_checker.go -fake-name HealthChecker . healthChecker

// healthChecker defines the contract for health checker
type healthChecker interface {
	RegisterChecker(component string, checker healthz.HealthChecker) error
}

// New creates a Kafka-based consenter. Called by orderer's main.go.
func New(config localconfig.Kafka, mp metrics.Provider, healthChecker healthChecker, icr InactiveChainRegistry, mkChain func(string)) (consensus.Consenter, *Metrics) {
	if config.Verbose {
		flogging.ActivateSpec(flogging.Global.Spec() + ":orderer.consensus.kafka.sarama=debug")
	}

	brokerConfig := newBrokerConfig(
		config.TLS,
		config.SASLPlain,
		config.Retry,
		config.Version,
		defaultPartition)

	metrics := NewMetrics(mp, brokerConfig.MetricRegistry)

	return &consenterImpl{
		mkChain:               mkChain,
		inactiveChainRegistry: icr,
		brokerConfigVal:       brokerConfig,
		tlsConfigVal:          config.TLS,
		retryOptionsVal:       config.Retry,
		kafkaVersionVal:       config.Version,
		topicDetailVal: &sarama.TopicDetail{
			NumPartitions:     1,
			ReplicationFactor: config.Topic.ReplicationFactor,
		},
		healthChecker: healthChecker,
		metrics:       metrics,
	}, metrics
}

// InactiveChainRegistry registers chains that are inactive
type InactiveChainRegistry interface {
	// TrackChain tracks a chain with the given name, and calls the given callback
	// when this chain should be created.
	TrackChain(chainName string, genesisBlock *cb.Block, createChain func())
}

// consenterImpl holds the implementation of type that satisfies the
// consensus.Consenter interface --as the HandleChain contract requires-- and
// the commonConsenter one.
type consenterImpl struct {
	mkChain               func(string)
	brokerConfigVal       *sarama.Config
	tlsConfigVal          localconfig.TLS
	retryOptionsVal       localconfig.Retry
	kafkaVersionVal       sarama.KafkaVersion
	topicDetailVal        *sarama.TopicDetail
	healthChecker         healthChecker
	metrics               *Metrics
	inactiveChainRegistry InactiveChainRegistry
}

// HandleChain creates/returns a reference to a consensus.Chain object for the
// given set of support resources. Implements the consensus.Consenter
// interface. Called by consensus.newChainSupport(), which is itself called by
// multichannel.NewManagerImpl() when ranging over the ledgerFactory's
// existingChains.
func (consenter *consenterImpl) HandleChain(support consensus.ConsenterSupport, metadata *cb.Metadata) (consensus.Chain, error) {

	// Check if this node was migrated from Raft
	if consenter.inactiveChainRegistry != nil {
		logger.Infof("This node was migrated from Kafka to Raft, skipping activation of Kafka chain")
		consenter.inactiveChainRegistry.TrackChain(support.ChannelID(), support.Block(0), func() {
			consenter.mkChain(support.ChannelID())
		})
		return &inactive.Chain{Err: errors.Errorf("channel %s is not serviced by me", support.ChannelID())}, nil
	}

	lastOffsetPersisted, lastOriginalOffsetProcessed, lastResubmittedConfigOffset := getOffsets(metadata.Value, support.ChannelID())
	ch, err := newChain(consenter, support, lastOffsetPersisted, lastOriginalOffsetProcessed, lastResubmittedConfigOffset)
	if err != nil {
		return nil, err
	}
	consenter.healthChecker.RegisterChecker(ch.channel.String(), ch)
	return ch, nil
}

func (c *consenterImpl) JoinChain(support consensus.ConsenterSupport, joinBlock *cb.Block) (consensus.Chain, error) {
	return nil, errors.New("the Kafka orderer does not support JoinChain")
}

// commonConsenter allows us to retrieve the configuration options set on the
// consenter object. These will be common across all chain objects derived by
// this consenter. They are set using local configuration settings. This
// interface is satisfied by consenterImpl.
type commonConsenter interface {
	brokerConfig() *sarama.Config
	retryOptions() localconfig.Retry
	topicDetail() *sarama.TopicDetail
	Metrics() *Metrics
}

func (consenter *consenterImpl) Metrics() *Metrics {
	return consenter.metrics
}

func (consenter *consenterImpl) brokerConfig() *sarama.Config {
	return consenter.brokerConfigVal
}

func (consenter *consenterImpl) retryOptions() localconfig.Retry {
	return consenter.retryOptionsVal
}

func (consenter *consenterImpl) topicDetail() *sarama.TopicDetail {
	return consenter.topicDetailVal
}
