/*
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You 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 consumer

import (
	"context"
	"encoding/json"
	"fmt"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/pkg/errors"
	"github.com/tidwall/gjson"

	"github.com/apache/rocketmq-client-go/internal"
	"github.com/apache/rocketmq-client-go/internal/remote"
	"github.com/apache/rocketmq-client-go/internal/utils"
	"github.com/apache/rocketmq-client-go/primitive"
	"github.com/apache/rocketmq-client-go/rlog"
)

const (
	// Delay some time when exception error
	_PullDelayTimeWhenError = 3 * time.Second

	// Flow control interval
	_PullDelayTimeWhenFlowControl = 50 * time.Millisecond

	// Delay some time when suspend pull service
	_PullDelayTimeWhenSuspend = 30 * time.Second

	// Long polling mode, the Consumer connection max suspend time
	_BrokerSuspendMaxTime = 20 * time.Second

	// Long polling mode, the Consumer connection timeout (must greater than _BrokerSuspendMaxTime)
	_ConsumerTimeoutWhenSuspend = 30 * time.Second

	// Offset persistent interval for consumer
	_PersistConsumerOffsetInterval = 5 * time.Second
)

type ConsumeType string

const (
	_PullConsume = ConsumeType("pull")
	_PushConsume = ConsumeType("push")

	_SubAll = "*"
)

var (
	ErrCreated        = errors.New("consumer group has been created")
	ErrBrokerNotFound = errors.New("broker can not found")
)

// Message model defines the way how messages are delivered to each consumer clients.
// </p>
//
// RocketMQ supports two message models: clustering and broadcasting. If clustering is set, consumer clients with
// the same {@link #ConsumerGroup} would only consume shards of the messages subscribed, which achieves load
// balances; Conversely, if the broadcasting is set, each consumer client will consume all subscribed messages
// separately.
// </p>
//
// This field defaults to clustering.
type MessageModel int

const (
	BroadCasting MessageModel = iota
	Clustering
)

func (mode MessageModel) String() string {
	switch mode {
	case BroadCasting:
		return "BroadCasting"
	case Clustering:
		return "Clustering"
	default:
		return "Unknown"
	}
}

// Consuming point on consumer booting.
// </p>
//
// There are three consuming points:
// <ul>
// <li>
// <code>CONSUME_FROM_LAST_OFFSET</code>: consumer clients pick up where it stopped previously.
// If it were a newly booting up consumer client, according aging of the consumer group, there are two
// cases:
// <ol>
// <li>
// if the consumer group is created so recently that the earliest message being subscribed has yet
// expired, which means the consumer group represents a lately launched business, consuming will
// start from the very beginning;
// </li>
// <li>
// if the earliest message being subscribed has expired, consuming will start from the latest
// messages, meaning messages born prior to the booting timestamp would be ignored.
// </li>
// </ol>
// </li>
// <li>
// <code>CONSUME_FROM_FIRST_OFFSET</code>: Consumer client will start from earliest messages available.
// </li>
// <li>
// <code>CONSUME_FROM_TIMESTAMP</code>: Consumer client will start from specified timestamp, which means
// messages born prior to {@link #consumeTimestamp} will be ignored
// </li>
// </ul>
type ConsumeFromWhere int

const (
	ConsumeFromLastOffset ConsumeFromWhere = iota
	ConsumeFromFirstOffset
	ConsumeFromTimestamp
)

type ExpressionType string

const (
	/**
	 * <ul>
	 * Keywords:
	 * <li>{@code AND, OR, NOT, BETWEEN, IN, TRUE, FALSE, IS, NULL}</li>
	 * </ul>
	 * <p/>
	 * <ul>
	 * Data type:
	 * <li>Boolean, like: TRUE, FALSE</li>
	 * <li>String, like: 'abc'</li>
	 * <li>Decimal, like: 123</li>
	 * <li>Float number, like: 3.1415</li>
	 * </ul>
	 * <p/>
	 * <ul>
	 * Grammar:
	 * <li>{@code AND, OR}</li>
	 * <li>{@code >, >=, <, <=, =}</li>
	 * <li>{@code BETWEEN A AND B}, equals to {@code >=A AND <=B}</li>
	 * <li>{@code NOT BETWEEN A AND B}, equals to {@code >B OR <A}</li>
	 * <li>{@code IN ('a', 'b')}, equals to {@code ='a' OR ='b'}, this operation only support String type.</li>
	 * <li>{@code IS NULL}, {@code IS NOT NULL}, check parameter whether is null, or not.</li>
	 * <li>{@code =TRUE}, {@code =FALSE}, check parameter whether is true, or false.</li>
	 * </ul>
	 * <p/>
	 * <p>
	 * Example:
	 * (a > 10 AND a < 100) OR (b IS NOT NULL AND b=TRUE)
	 * </p>
	 */
	SQL92 = ExpressionType("SQL92")

	/**
	 * Only support or operation such as
	 * "tag1 || tag2 || tag3", <br>
	 * If null or * expression, meaning subscribe all.
	 */
	TAG = ExpressionType("TAG")
)

func IsTagType(exp string) bool {
	if exp == "" || exp == "TAG" {
		return true
	}
	return false
}

type MessageSelector struct {
	Type       ExpressionType
	Expression string
}

type ConsumeResult int

const (
	ConsumeSuccess ConsumeResult = iota
	ConsumeRetryLater
	Commit
	Rollback
	SuspendCurrentQueueAMoment
)

type ConsumeResultHolder struct {
	ConsumeResult
}

type ConsumerReturn int

const (
	SuccessReturn ConsumerReturn = iota
	ExceptionReturn
	NullReturn
	TimeoutReturn
	FailedReturn
)

type PullRequest struct {
	consumerGroup string
	mq            *primitive.MessageQueue
	pq            *processQueue
	nextOffset    int64
	lockedFirst   bool
}

func (pr *PullRequest) String() string {
	return fmt.Sprintf("[ConsumerGroup: %s, Topic: %s, MessageQueue: %d]",
		pr.consumerGroup, pr.mq.Topic, pr.mq.QueueId)
}

type defaultConsumer struct {
	/**
	 * Consumers of the same role is required to have exactly same subscriptions and consumerGroup to correctly achieve
	 * load balance. It's required and needs to be globally unique.
	 * </p>
	 *
	 * See <a href="http://rocketmq.apache.org/docs/core-concept/">here</a> for further discussion.
	 */
	consumerGroup          string
	model                  MessageModel
	allocate               func(string, string, []*primitive.MessageQueue, []string) []*primitive.MessageQueue
	unitMode               bool
	consumeOrderly         bool
	fromWhere              ConsumeFromWhere
	consumerStartTimestamp int64

	cType     ConsumeType
	client    internal.RMQClient
	mqChanged func(topic string, mqAll, mqDivided []*primitive.MessageQueue)
	state     internal.ServiceState
	pause     bool
	once      sync.Once
	option    consumerOptions
	// key: primitive.MessageQueue
	// value: *processQueue
	processQueueTable sync.Map

	// key: topic(string)
	// value: map[int]*primitive.MessageQueue
	topicSubscribeInfoTable sync.Map

	// key: topic
	// value: *SubscriptionData
	subscriptionDataTable sync.Map
	storage               OffsetStore
	// chan for push consumer
	prCh chan PullRequest

	namesrv internal.Namesrvs
}

func (dc *defaultConsumer) start() error {

	if dc.model == Clustering {
		// set retry topic
		retryTopic := internal.GetRetryTopic(dc.consumerGroup)
		sub := buildSubscriptionData(retryTopic, MessageSelector{TAG, _SubAll})
		dc.subscriptionDataTable.Store(retryTopic, sub)
	}

	if dc.model == Clustering {
		dc.option.ChangeInstanceNameToPID()
		dc.storage = NewRemoteOffsetStore(dc.consumerGroup, dc.client, dc.namesrv)
	} else {
		dc.storage = NewLocalFileOffsetStore(dc.consumerGroup, dc.client.ClientID())
	}

	dc.client.UpdateTopicRouteInfo()
	dc.client.Start()
	dc.state = internal.StateRunning
	dc.consumerStartTimestamp = time.Now().UnixNano() / int64(time.Millisecond)
	return nil
}

func (dc *defaultConsumer) shutdown() error {
	dc.state = internal.StateShutdown
	mqs := make([]*primitive.MessageQueue, 0)
	dc.processQueueTable.Range(func(key, value interface{}) bool {
		k := key.(primitive.MessageQueue)
		pq := value.(*processQueue)
		pq.WithDropped(true)
		mqs = append(mqs, &k)
		return true
	})
	dc.storage.persist(mqs)
	dc.client.Shutdown()
	return nil
}

func (dc *defaultConsumer) persistConsumerOffset() error {
	err := dc.makeSureStateOK()
	if err != nil {
		return err
	}
	mqs := make([]*primitive.MessageQueue, 0)
	dc.processQueueTable.Range(func(key, value interface{}) bool {
		k := key.(primitive.MessageQueue)
		mqs = append(mqs, &k)
		return true
	})
	dc.storage.persist(mqs)
	return nil
}

func (dc *defaultConsumer) updateOffset(queue *primitive.MessageQueue, offset int64) error {
	dc.storage.update(queue, offset, false)
	return nil
}

func (dc *defaultConsumer) subscriptionAutomatically(topic string) {
	_, exist := dc.subscriptionDataTable.Load(topic)
	if !exist {
		s := MessageSelector{
			Expression: _SubAll,
		}
		dc.subscriptionDataTable.Store(topic, buildSubscriptionData(topic, s))
	}
}

func (dc *defaultConsumer) updateTopicSubscribeInfo(topic string, mqs []*primitive.MessageQueue) {
	_, exist := dc.subscriptionDataTable.Load(topic)
	// does subscribe, if true, replace it
	if exist {
		mqSet := make(map[int]*primitive.MessageQueue, 0)
		for idx := range mqs {
			mq := mqs[idx]
			mqSet[mq.HashCode()] = mq
		}
		dc.topicSubscribeInfoTable.Store(topic, mqs)
	}
}

func (dc *defaultConsumer) isSubscribeTopicNeedUpdate(topic string) bool {
	_, exist := dc.subscriptionDataTable.Load(topic)
	if !exist {
		return false
	}
	_, exist = dc.topicSubscribeInfoTable.Load(topic)
	return !exist
}

func (dc *defaultConsumer) doBalance() {
	dc.subscriptionDataTable.Range(func(key, value interface{}) bool {
		topic := key.(string)
		v, exist := dc.topicSubscribeInfoTable.Load(topic)
		if !exist {
			rlog.Warning("do balance in group failed, the topic does not exist", map[string]interface{}{
				rlog.LogKeyConsumerGroup: dc.consumerGroup,
				rlog.LogKeyTopic:         topic,
			})
			return true
		}
		mqs := v.([]*primitive.MessageQueue)
		switch dc.model {
		case BroadCasting:
			changed := dc.updateProcessQueueTable(topic, mqs)
			if changed {
				dc.mqChanged(topic, mqs, mqs)
				rlog.Debug("MessageQueue changed", map[string]interface{}{
					rlog.LogKeyConsumerGroup: dc.consumerGroup,
					rlog.LogKeyTopic:         topic,
					rlog.LogKeyMessageQueue:  fmt.Sprintf("%v", mqs),
				})
			}
		case Clustering:
			cidAll := dc.findConsumerList(topic)
			if cidAll == nil {
				rlog.Warning("do balance in group failed, get consumer id list failed", map[string]interface{}{
					rlog.LogKeyConsumerGroup: dc.consumerGroup,
					rlog.LogKeyTopic:         topic,
				})
				return true
			}
			mqAll := make([]*primitive.MessageQueue, len(mqs))
			copy(mqAll, mqs)
			sort.Strings(cidAll)
			sort.SliceStable(mqAll, func(i, j int) bool {
				v := strings.Compare(mqAll[i].Topic, mqAll[j].Topic)
				if v != 0 {
					return v > 0
				}

				v = strings.Compare(mqAll[i].BrokerName, mqAll[j].BrokerName)
				if v != 0 {
					return v > 0
				}
				return (mqAll[i].QueueId - mqAll[j].QueueId) < 0
			})
			allocateResult := dc.allocate(dc.consumerGroup, dc.client.ClientID(), mqAll, cidAll)
			changed := dc.updateProcessQueueTable(topic, allocateResult)
			if changed {
				dc.mqChanged(topic, mqAll, allocateResult)
				rlog.Debug("MessageQueue do balance done", map[string]interface{}{
					rlog.LogKeyConsumerGroup: dc.consumerGroup,
					rlog.LogKeyTopic:         topic,
					"clientID":               dc.client.ClientID(),
					"mqAllSize":              len(mqAll),
					"cidAllSize":             len(cidAll),
					"rebalanceResultSize":    len(allocateResult),
					"rebalanceResultSet":     allocateResult,
				})
			}
		}
		return true
	})
}

func (dc *defaultConsumer) SubscriptionDataList() []*internal.SubscriptionData {
	result := make([]*internal.SubscriptionData, 0)
	dc.subscriptionDataTable.Range(func(key, value interface{}) bool {
		result = append(result, value.(*internal.SubscriptionData))
		return true
	})
	return result
}

func (dc *defaultConsumer) makeSureStateOK() error {
	if dc.state != internal.StateRunning {
		return fmt.Errorf("state not running, actually: %v", dc.state)
	}
	return nil
}

type lockBatchRequestBody struct {
	ConsumerGroup string                    `json:"consumerGroup"`
	ClientId      string                    `json:"clientId"`
	MQs           []*primitive.MessageQueue `json:"mqSet"`
}

func (dc *defaultConsumer) lock(mq *primitive.MessageQueue) bool {
	brokerResult := dc.namesrv.FindBrokerAddressInSubscribe(mq.BrokerName, internal.MasterId, true)

	if brokerResult == nil {
		return false
	}

	body := &lockBatchRequestBody{
		ConsumerGroup: dc.consumerGroup,
		ClientId:      dc.client.ClientID(),
		MQs:           []*primitive.MessageQueue{mq},
	}
	lockedMQ := dc.doLock(brokerResult.BrokerAddr, body)
	var lockOK bool
	for idx := range lockedMQ {
		_mq := lockedMQ[idx]
		v, exist := dc.processQueueTable.Load(_mq)
		if exist {
			pq := v.(*processQueue)
			pq.WithLock(true)
			pq.lastConsumeTime = time.Now()
			pq.lastLockTime = time.Now()
		}
		if _mq.Equals(mq) {
			lockOK = true
		}
	}
	fields := map[string]interface{}{
		"lockOK":                 lockOK,
		rlog.LogKeyConsumerGroup: dc.consumerGroup,
		rlog.LogKeyMessageQueue:  mq.String(),
	}
	if lockOK {
		rlog.Debug("lock MessageQueue", fields)
	} else {
		rlog.Info("lock MessageQueue", fields)
	}
	return lockOK
}

func (dc *defaultConsumer) unlock(mq *primitive.MessageQueue, oneway bool) {
	brokerResult := dc.namesrv.FindBrokerAddressInSubscribe(mq.BrokerName, internal.MasterId, true)

	if brokerResult == nil {
		return
	}

	body := &lockBatchRequestBody{
		ConsumerGroup: dc.consumerGroup,
		ClientId:      dc.client.ClientID(),
		MQs:           []*primitive.MessageQueue{mq},
	}
	dc.doUnlock(brokerResult.BrokerAddr, body, oneway)
	rlog.Info("unlock MessageQueue", map[string]interface{}{
		rlog.LogKeyConsumerGroup: dc.consumerGroup,
		"clientID":               dc.client.ClientID(),
		rlog.LogKeyMessageQueue:  mq.String(),
	})
}

func (dc *defaultConsumer) lockAll() {
	mqMapSet := dc.buildProcessQueueTableByBrokerName()
	for broker, mqs := range mqMapSet {
		if len(mqs) == 0 {
			continue
		}
		brokerResult := dc.namesrv.FindBrokerAddressInSubscribe(broker, internal.MasterId, true)
		if brokerResult == nil {
			continue
		}
		body := &lockBatchRequestBody{
			ConsumerGroup: dc.consumerGroup,
			ClientId:      dc.client.ClientID(),
			MQs:           mqs,
		}
		lockedMQ := dc.doLock(brokerResult.BrokerAddr, body)
		set := make(map[primitive.MessageQueue]bool)
		for idx := range lockedMQ {
			_mq := lockedMQ[idx]
			v, exist := dc.processQueueTable.Load(_mq)
			if exist {
				pq := v.(*processQueue)
				pq.WithLock(true)
				pq.lastConsumeTime = time.Now()
			}
			set[_mq] = true
		}
		for idx := range mqs {
			_mq := mqs[idx]
			if !set[*_mq] {
				v, exist := dc.processQueueTable.Load(_mq)
				if exist {
					pq := v.(*processQueue)
					pq.WithLock(false)
					pq.lastLockTime = time.Now()
					rlog.Info("lock MessageQueue", map[string]interface{}{
						"lockOK":                 false,
						rlog.LogKeyConsumerGroup: dc.consumerGroup,
						rlog.LogKeyMessageQueue:  _mq.String(),
					})
				}
			}
		}
	}
}

func (dc *defaultConsumer) unlockAll(oneway bool) {
	mqMapSet := dc.buildProcessQueueTableByBrokerName()
	for broker, mqs := range mqMapSet {
		if len(mqs) == 0 {
			continue
		}
		brokerResult := dc.namesrv.FindBrokerAddressInSubscribe(broker, internal.MasterId, true)
		if brokerResult == nil {
			continue
		}
		body := &lockBatchRequestBody{
			ConsumerGroup: dc.consumerGroup,
			ClientId:      dc.client.ClientID(),
			MQs:           mqs,
		}
		dc.doUnlock(brokerResult.BrokerAddr, body, oneway)
		for idx := range mqs {
			_mq := mqs[idx]
			v, exist := dc.processQueueTable.Load(_mq)
			if exist {
				rlog.Info("lock MessageQueue", map[string]interface{}{
					"lockOK":                 false,
					rlog.LogKeyConsumerGroup: dc.consumerGroup,
					rlog.LogKeyMessageQueue:  _mq.String(),
				})
				v.(*processQueue).WithLock(false)
			}
		}
	}
}

func (dc *defaultConsumer) doLock(addr string, body *lockBatchRequestBody) []primitive.MessageQueue {
	data, _ := json.Marshal(body)
	request := remote.NewRemotingCommand(internal.ReqLockBatchMQ, nil, data)
	response, err := dc.client.InvokeSync(context.Background(), addr, request, 1*time.Second)
	if err != nil {
		rlog.Error("lock MessageQueue to broker invoke error", map[string]interface{}{
			rlog.LogKeyBroker:        addr,
			rlog.LogKeyUnderlayError: err,
		})
		return nil
	}
	lockOKMQSet := struct {
		MQs []primitive.MessageQueue `json:"lockOKMQSet"`
	}{}
	if len(response.Body) == 0 {
		return nil
	}
	err = json.Unmarshal(response.Body, &lockOKMQSet)
	if err != nil {
		rlog.Error("Unmarshal lock mq body error", map[string]interface{}{
			rlog.LogKeyUnderlayError: err,
		})
		return nil
	}
	return lockOKMQSet.MQs
}

func (dc *defaultConsumer) doUnlock(addr string, body *lockBatchRequestBody, oneway bool) {
	data, _ := json.Marshal(body)
	request := remote.NewRemotingCommand(internal.ReqUnlockBatchMQ, nil, data)
	if oneway {
		err := dc.client.InvokeOneWay(context.Background(), addr, request, 3*time.Second)
		if err != nil {
			rlog.Error("lock MessageQueue to broker invoke oneway error", map[string]interface{}{
				rlog.LogKeyBroker:        addr,
				rlog.LogKeyUnderlayError: err,
			})
		}
	} else {
		response, err := dc.client.InvokeSync(context.Background(), addr, request, 1*time.Second)
		rlog.Error("lock MessageQueue to broker invoke error", map[string]interface{}{
			rlog.LogKeyBroker:        addr,
			rlog.LogKeyUnderlayError: err,
		})
		if response.Code != internal.ResSuccess {
			// TODO error
		}
	}
}

func (dc *defaultConsumer) buildProcessQueueTableByBrokerName() map[string][]*primitive.MessageQueue {
	result := make(map[string][]*primitive.MessageQueue, 0)

	dc.processQueueTable.Range(func(key, value interface{}) bool {
		mq := key.(primitive.MessageQueue)
		mqs, exist := result[mq.BrokerName]
		if !exist {
			mqs = make([]*primitive.MessageQueue, 0)
		}
		mqs = append(mqs, &mq)
		result[mq.BrokerName] = mqs
		return true
	})

	return result
}

// TODO 问题不少 需要再好好对一下
func (dc *defaultConsumer) updateProcessQueueTable(topic string, mqs []*primitive.MessageQueue) bool {
	var changed bool
	mqSet := make(map[primitive.MessageQueue]bool)
	for idx := range mqs {
		mqSet[*mqs[idx]] = true
	}
	// TODO
	dc.processQueueTable.Range(func(key, value interface{}) bool {
		mq := key.(primitive.MessageQueue)
		pq := value.(*processQueue)
		if mq.Topic == topic {
			if !mqSet[mq] {
				pq.WithDropped(true)
				if dc.removeUnnecessaryMessageQueue(&mq, pq) {
					dc.processQueueTable.Delete(key)
					changed = true
					rlog.Debug("remove unnecessary mq when updateProcessQueueTable", map[string]interface{}{
						rlog.LogKeyConsumerGroup: dc.consumerGroup,
						rlog.LogKeyMessageQueue:  mq.String(),
					})
				}
			} else if pq.isPullExpired() && dc.cType == _PushConsume {
				pq.WithDropped(true)
				if dc.removeUnnecessaryMessageQueue(&mq, pq) {
					dc.processQueueTable.Delete(key)
					changed = true
					rlog.Debug("remove unnecessary mq because pull was paused, prepare to fix it", map[string]interface{}{
						rlog.LogKeyConsumerGroup: dc.consumerGroup,
						rlog.LogKeyMessageQueue:  mq.String(),
					})
				}
			}
		}
		return true
	})

	if dc.cType == _PushConsume {
		for item := range mqSet {
			// BUG: the mq will send to channel, if not copy once, the next iter will modify the mq in the channel.
			mq := item
			_, exist := dc.processQueueTable.Load(mq)
			if exist {
				continue
			}
			if dc.consumeOrderly && !dc.lock(&mq) {
				rlog.Warning("do defaultConsumer, add a new mq failed, because lock failed", map[string]interface{}{
					rlog.LogKeyConsumerGroup: dc.consumerGroup,
					rlog.LogKeyMessageQueue:  mq.String(),
				})
				continue
			}
			dc.storage.remove(&mq)
			nextOffset := dc.computePullFromWhere(&mq)
			if nextOffset >= 0 {
				_, exist := dc.processQueueTable.Load(mq)
				if exist {
					rlog.Debug("do defaultConsumer, mq already exist", map[string]interface{}{
						rlog.LogKeyConsumerGroup: dc.consumerGroup,
						rlog.LogKeyMessageQueue:  mq.String(),
					})
				} else {
					rlog.Debug("do defaultConsumer, add a new mq", map[string]interface{}{
						rlog.LogKeyConsumerGroup: dc.consumerGroup,
						rlog.LogKeyMessageQueue:  mq.String(),
					})
					pq := newProcessQueue(dc.consumeOrderly)
					dc.processQueueTable.Store(mq, pq)
					pr := PullRequest{
						consumerGroup: dc.consumerGroup,
						mq:            &mq,
						pq:            pq,
						nextOffset:    nextOffset,
					}
					dc.prCh <- pr
					changed = true
				}
			} else {
				rlog.Warning("do defaultConsumer, add a new mq failed", map[string]interface{}{
					rlog.LogKeyConsumerGroup: dc.consumerGroup,
					rlog.LogKeyMessageQueue:  mq.String(),
				})
			}
		}
	}

	return changed
}

func (dc *defaultConsumer) removeUnnecessaryMessageQueue(mq *primitive.MessageQueue, pq *processQueue) bool {
	dc.storage.persist([]*primitive.MessageQueue{mq})
	dc.storage.remove(mq)
	return true
}

func (dc *defaultConsumer) computePullFromWhere(mq *primitive.MessageQueue) int64 {
	if dc.cType == _PullConsume {
		return 0
	}
	var result = int64(-1)
	lastOffset := dc.storage.read(mq, _ReadFromStore)
	if lastOffset >= 0 {
		result = lastOffset
	} else {
		switch dc.option.FromWhere {
		case ConsumeFromLastOffset:
			if lastOffset == -1 {
				if strings.HasPrefix(mq.Topic, internal.RetryGroupTopicPrefix) {
					lastOffset = 0
				} else {
					lastOffset, err := dc.queryMaxOffset(mq)
					if err == nil {
						result = lastOffset
					} else {
						rlog.Warning("query max offset error", map[string]interface{}{
							rlog.LogKeyMessageQueue:  mq,
							rlog.LogKeyUnderlayError: err,
						})
					}
				}
			} else {
				result = -1
			}
		case ConsumeFromFirstOffset:
			if lastOffset == -1 {
				result = 0
			}
		case ConsumeFromTimestamp:
			if lastOffset == -1 {
				if strings.HasPrefix(mq.Topic, internal.RetryGroupTopicPrefix) {
					lastOffset, err := dc.queryMaxOffset(mq)
					if err == nil {
						result = lastOffset
					} else {
						result = -1
						rlog.Warning("query max offset error", map[string]interface{}{
							rlog.LogKeyMessageQueue:  mq,
							rlog.LogKeyUnderlayError: err,
						})
					}
				} else {
					t, err := time.Parse("20060102150405", dc.option.ConsumeTimestamp)
					if err != nil {
						result = -1
					} else {
						lastOffset, err := dc.searchOffsetByTimestamp(mq, t.Unix()*1000)
						if err != nil {
							result = -1
						} else {
							result = lastOffset
						}
					}
				}
			}
		default:
		}
	}
	return result
}

func (dc *defaultConsumer) pullInner(ctx context.Context, queue *primitive.MessageQueue, data *internal.SubscriptionData,
	offset int64, numbers int, sysFlag int32, commitOffsetValue int64) (*primitive.PullResult, error) {

	brokerResult := dc.tryFindBroker(queue)
	if brokerResult == nil {
		rlog.Warning("no broker found for mq", map[string]interface{}{
			rlog.LogKeyMessageQueue: queue,
		})
		return nil, ErrBrokerNotFound
	}

	if brokerResult.Slave {
		sysFlag = clearCommitOffsetFlag(sysFlag)
	}

	if (data.ExpType == string(TAG)) && brokerResult.BrokerVersion < internal.V4_1_0 {
		return nil, fmt.Errorf("the broker [%s, %v] does not upgrade to support for filter message by %v",
			queue.BrokerName, brokerResult.BrokerVersion, data.ExpType)
	}

	pullRequest := &internal.PullMessageRequestHeader{
		ConsumerGroup: dc.consumerGroup,
		Topic:         queue.Topic,
		QueueId:       int32(queue.QueueId),
		QueueOffset:   offset,
		MaxMsgNums:    int32(numbers),
		SysFlag:       sysFlag,
		CommitOffset:  commitOffsetValue,
		// TODO: 和java对齐
		SuspendTimeoutMillis: _BrokerSuspendMaxTime,
		SubExpression:        data.SubString,
		// TODO: add subversion
		ExpressionType: string(data.ExpType),
	}

	if data.ExpType == string(TAG) {
		pullRequest.SubVersion = 0
	} else {
		pullRequest.SubVersion = data.SubVersion
	}

	// TODO: add computPullFromWhichFilterServer

	return dc.client.PullMessage(context.Background(), brokerResult.BrokerAddr, pullRequest)
}

func (dc *defaultConsumer) processPullResult(mq *primitive.MessageQueue, result *primitive.PullResult, data *internal.SubscriptionData) {

	updatePullFromWhichNode(mq, result.SuggestWhichBrokerId)

	switch result.Status {
	case primitive.PullFound:
		result.SetMessageExts(primitive.DecodeMessage(result.GetBody()))
		msgs := result.GetMessageExts()

		// filter message according to tags
		msgListFilterAgain := msgs
		if data.Tags.Len() > 0 && data.ClassFilterMode {
			msgListFilterAgain = make([]*primitive.MessageExt, 0)
			for _, msg := range msgs {
				_, exist := data.Tags.Contains(msg.GetTags())
				if exist {
					msgListFilterAgain = append(msgListFilterAgain, msg)
				}
			}
		}

		// TODO: add filter message hook
		for _, msg := range msgListFilterAgain {
			traFlag, _ := strconv.ParseBool(msg.GetProperty(primitive.PropertyTransactionPrepared))
			if traFlag {
				msg.TransactionId = msg.GetProperty(primitive.PropertyUniqueClientMessageIdKeyIndex)
			}

			msg.WithProperty(primitive.PropertyMinOffset, strconv.FormatInt(result.MinOffset, 10))
			msg.WithProperty(primitive.PropertyMaxOffset, strconv.FormatInt(result.MaxOffset, 10))
		}

		result.SetMessageExts(msgListFilterAgain)
	}
}

func (dc *defaultConsumer) findConsumerList(topic string) []string {
	brokerAddr := dc.namesrv.FindBrokerAddrByTopic(topic)
	if brokerAddr == "" {
		dc.namesrv.UpdateTopicRouteInfo(topic)
		brokerAddr = dc.namesrv.FindBrokerAddrByTopic(topic)
	}

	if brokerAddr != "" {
		req := &internal.GetConsumerListRequestHeader{
			ConsumerGroup: dc.consumerGroup,
		}
		cmd := remote.NewRemotingCommand(internal.ReqGetConsumerListByGroup, req, nil)
		res, err := dc.client.InvokeSync(context.Background(), brokerAddr, cmd, 3*time.Second) // TODO 超时机制有问题
		if err != nil {
			rlog.Error("get consumer list of group from broker error", map[string]interface{}{
				rlog.LogKeyConsumerGroup: dc.consumerGroup,
				rlog.LogKeyBroker:        brokerAddr,
				rlog.LogKeyUnderlayError: err,
			})
			return nil
		}
		result := gjson.ParseBytes(res.Body)
		list := make([]string, 0)
		arr := result.Get("consumerIdList").Array()
		for idx := range arr {
			list = append(list, arr[idx].String())
		}
		return list
	}
	return nil
}

func (dc *defaultConsumer) sendBack(msg *primitive.MessageExt, level int) error {
	return nil
}

// QueryMaxOffset with specific queueId and topic
func (dc *defaultConsumer) queryMaxOffset(mq *primitive.MessageQueue) (int64, error) {
	brokerAddr := dc.namesrv.FindBrokerAddrByName(mq.BrokerName)
	if brokerAddr == "" {
		dc.namesrv.UpdateTopicRouteInfo(mq.Topic)
		brokerAddr = dc.namesrv.FindBrokerAddrByName(mq.Topic)
	}
	if brokerAddr == "" {
		return -1, fmt.Errorf("the broker [%s] does not exist", mq.BrokerName)
	}

	request := &internal.GetMaxOffsetRequestHeader{
		Topic:   mq.Topic,
		QueueId: mq.QueueId,
	}

	cmd := remote.NewRemotingCommand(internal.ReqGetMaxOffset, request, nil)
	response, err := dc.client.InvokeSync(context.Background(), brokerAddr, cmd, 3*time.Second)
	if err != nil {
		return -1, err
	}

	return strconv.ParseInt(response.ExtFields["offset"], 10, 64)
}

func (dc *defaultConsumer) queryOffset(mq *primitive.MessageQueue) int64 {
	return dc.storage.read(mq, _ReadMemoryThenStore)
}

// SearchOffsetByTimestamp with specific queueId and topic
func (dc *defaultConsumer) searchOffsetByTimestamp(mq *primitive.MessageQueue, timestamp int64) (int64, error) {
	brokerAddr := dc.namesrv.FindBrokerAddrByName(mq.BrokerName)
	if brokerAddr == "" {
		dc.namesrv.UpdateTopicRouteInfo(mq.Topic)
		brokerAddr = dc.namesrv.FindBrokerAddrByName(mq.Topic)
	}
	if brokerAddr == "" {
		return -1, fmt.Errorf("the broker [%s] does not exist", mq.BrokerName)
	}

	request := &internal.SearchOffsetRequestHeader{
		Topic:     mq.Topic,
		QueueId:   mq.QueueId,
		Timestamp: timestamp,
	}

	cmd := remote.NewRemotingCommand(internal.ReqSearchOffsetByTimestamp, request, nil)
	response, err := dc.client.InvokeSync(context.Background(), brokerAddr, cmd, 3*time.Second)
	if err != nil {
		return -1, err
	}

	return strconv.ParseInt(response.ExtFields["offset"], 10, 64)
}

func buildSubscriptionData(topic string, selector MessageSelector) *internal.SubscriptionData {
	subData := &internal.SubscriptionData{
		Topic:     topic,
		SubString: selector.Expression,
		ExpType:   string(selector.Type),
	}

	if selector.Type != "" && selector.Type != TAG {
		return subData
	}

	if selector.Expression == "" || selector.Expression == _SubAll {
		subData.ExpType = string(TAG)
		subData.SubString = _SubAll
	} else {
		tags := strings.Split(selector.Expression, "||")
		subData.Tags = utils.NewSet()
		subData.Codes = utils.NewSet()
		for idx := range tags {
			trimString := strings.Trim(tags[idx], " ")
			if trimString != "" {
				if _, ok := subData.Tags.Contains(trimString); !ok {
					subData.Tags.AddKV(trimString, trimString)
				}
				hCode := utils.HashString(trimString)
				v := strconv.Itoa(hCode)
				if _, ok := subData.Codes.Contains(v); !ok {
					subData.Codes.AddKV(v, v)
				}
			}
		}
	}
	return subData
}

func buildSysFlag(commitOffset, suspend, subscription, classFilter bool) int32 {
	var flag int32 = 0
	if commitOffset {
		flag |= 0x1 << 0
	}

	if suspend {
		flag |= 0x1 << 1
	}

	if subscription {
		flag |= 0x1 << 2
	}

	if classFilter {
		flag |= 0x1 << 3
	}

	return flag
}

func clearCommitOffsetFlag(sysFlag int32) int32 {
	return sysFlag & (^0x1 << 0)
}

func (dc *defaultConsumer) tryFindBroker(mq *primitive.MessageQueue) *internal.FindBrokerResult {
	result := dc.namesrv.FindBrokerAddressInSubscribe(mq.BrokerName, recalculatePullFromWhichNode(mq), false)
	if result != nil {
		return result
	}
	dc.namesrv.UpdateTopicRouteInfo(mq.Topic)
	return dc.namesrv.FindBrokerAddressInSubscribe(mq.BrokerName, recalculatePullFromWhichNode(mq), false)
}

var (
	pullFromWhichNodeTable sync.Map
)

func updatePullFromWhichNode(mq *primitive.MessageQueue, brokerId int64) {
	pullFromWhichNodeTable.Store(mq.HashCode(), brokerId)
}

func recalculatePullFromWhichNode(mq *primitive.MessageQueue) int64 {
	v, exist := pullFromWhichNodeTable.Load(mq.HashCode())
	if exist {
		return v.(int64)
	}
	return internal.MasterId
}