// Copyright Fuzamei Corp. 2018 All Rights Reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package blockchain

import (
	"bytes"
	"math/big"
	"sort"
	"sync"
	"sync/atomic"
	"time"

	"github.com/33cn/chain33/common"
	"github.com/33cn/chain33/types"
)

//var
var (
	synBlocklock     sync.Mutex
	peerMaxBlklock   sync.Mutex
	castlock         sync.Mutex
	ntpClockSynclock sync.Mutex
	faultpeerlock    sync.Mutex
	bestpeerlock     sync.Mutex

	isNtpClockSync = true //ntp时间是否同步

	MaxFetchBlockNum        int64 = 128 * 6 //一次最多申请获取block个数
	TimeoutSeconds          int64 = 2
	BackBlockNum            int64 = 128    //节点高度不增加时向后取blocks的个数
	BackwardBlockNum        int64 = 16     //本节点高度不增加时并且落后peer的高度数
	checkHeightNoIncSeconds int64 = 5 * 60 //高度不增长时的检测周期目前暂定5分钟
	checkBlockHashSeconds   int64 = 1 * 60 //1分钟检测一次tip hash和peer 对应高度的hash是否一致
	fetchPeerListSeconds    int64 = 5      //5 秒获取一个peerlist
	MaxRollBlockNum         int64 = 10000  //最大回退block数量
	//TODO
	blockSynInterVal        = time.Duration(TimeoutSeconds)
	batchsyncblocknum int64 = 5000 //同步阶段，如果自己高度小于最大高度5000个时，saveblock到db时批量处理不刷盘

	synlog = chainlog.New("submodule", "syn")
)

//ForkInfo blockchain模块fork处理结构体
type ForkInfo struct {
	ForkStartHeight int64
	ForkEndHeight   int64
	ForkPid         string
}

//PeerInfo blockchain模块需要保存的peerinfo
type PeerInfo struct {
	Name       string
	ParentHash []byte
	Height     int64
	Hash       []byte
}

//PeerInfoList 节点列表
type PeerInfoList []*PeerInfo

//Len 长度
func (list PeerInfoList) Len() int {
	return len(list)
}

//Less 小于
func (list PeerInfoList) Less(i, j int) bool {
	if list[i].Height < list[j].Height {
		return true
	} else if list[i].Height > list[j].Height {
		return false
	} else {
		return list[i].Name < list[j].Name
	}
}

//Swap 交换
func (list PeerInfoList) Swap(i, j int) {
	temp := list[i]
	list[i] = list[j]
	list[j] = temp
}

//FaultPeerInfo 可疑故障节点信息
type FaultPeerInfo struct {
	Peer        *PeerInfo
	FaultHeight int64
	FaultHash   []byte
	ErrInfo     error
	ReqFlag     bool
}

//BestPeerInfo 用于记录最优链的信息
type BestPeerInfo struct {
	Peer        *PeerInfo
	Height      int64
	Hash        []byte
	Td          *big.Int
	ReqFlag     bool
	IsBestChain bool
}

//SynRoutine 同步事务
func (chain *BlockChain) SynRoutine() {
	//获取peerlist的定时器，默认1分钟
	fetchPeerListTicker := time.NewTicker(time.Duration(fetchPeerListSeconds) * time.Second)

	//向peer请求同步block的定时器，默认2s
	blockSynTicker := time.NewTicker(blockSynInterVal * time.Second)

	//5分钟检测一次bestchain主链高度是否有增长，如果没有增长可能是目前主链在侧链上，
	//需要从最高peer向后同步指定的headers用来获取分叉点，再后从指定peer获取分叉点以后的blocks
	checkHeightNoIncreaseTicker := time.NewTicker(time.Duration(checkHeightNoIncSeconds) * time.Second)

	//目前暂定1分钟检测一次本bestchain的tiphash和最高peer的对应高度的blockshash是否一致。
	//如果不一致可能两个节点在各自的链上挖矿，需要从peer的对应高度向后获取指定数量的headers寻找分叉点
	//考虑叉后的第一个block没有广播到本节点，导致接下来广播过来的blocks都是孤儿节点，无法进行主侧链总难度对比
	checkBlockHashTicker := time.NewTicker(time.Duration(checkBlockHashSeconds) * time.Second)

	//5分钟检测一次系统时间，不同步提示告警
	checkClockDriftTicker := time.NewTicker(300 * time.Second)

	//3分钟尝试检测一次故障peer是否已经恢复
	recoveryFaultPeerTicker := time.NewTicker(180 * time.Second)

	//2分钟尝试检测一次最优链，确保本节点在最优链
	checkBestChainTicker := time.NewTicker(120 * time.Second)

	for {
		select {
		case <-chain.quit:
			//synlog.Info("quit SynRoutine!")
			return
		case <-blockSynTicker.C:
			//synlog.Info("blockSynTicker")
			//SynBlocksFromPeers在task任务中也会go线程调用
			//WaitGroup不太好处理，暂时不加入WaitGroup中
			go chain.SynBlocksFromPeers()

		case <-fetchPeerListTicker.C:
			//synlog.Info("blockUpdateTicker")
			chain.tickerwg.Add(1)
			go chain.FetchPeerList()

		case <-checkHeightNoIncreaseTicker.C:
			//synlog.Info("CheckHeightNoIncrease")
			chain.tickerwg.Add(1)
			go chain.CheckHeightNoIncrease()

		case <-checkBlockHashTicker.C:
			//synlog.Info("checkBlockHashTicker")
			chain.tickerwg.Add(1)
			go chain.CheckTipBlockHash()

			//定时检查系统时间，如果系统时间有问题，那么会有一个报警
		case <-checkClockDriftTicker.C:
			// ntp可能存在一直没有回应的情况导致go线程不退出，暂时不在WaitGroup中处理
			go checkClockDrift()

			//定时检查故障peer，如果执行出错高度的blockhash值有变化，说明故障peer已经纠正
		case <-recoveryFaultPeerTicker.C:
			chain.tickerwg.Add(1)
			go chain.RecoveryFaultPeer()

			//定时检查peerlist中的节点是否在同一条链上，获取同一高度的blockhash来做对比
		case <-checkBestChainTicker.C:
			chain.tickerwg.Add(1)
			go chain.CheckBestChain(false)
		}
	}
}

/*
FetchBlock 函数功能：
通过向P2P模块送 EventFetchBlock(types.RequestGetBlock)，向其他节点主动请求区块，
P2P区块收到这个消息后，会向blockchain 模块回复， EventReply。
其他节点如果有这个范围的区块，P2P模块收到其他节点发来的数据，
会发送送EventAddBlocks(types.Blocks) 给 blockchain 模块，
blockchain 模块回复 EventReply
syncOrfork:true fork分叉处理，不需要处理请求block的个数
          :fasle 区块同步处理，一次请求128个block
*/
func (chain *BlockChain) FetchBlock(start int64, end int64, pid []string, syncOrfork bool) (err error) {
	if chain.client == nil {
		synlog.Error("FetchBlock chain client not bind message queue.")
		return types.ErrClientNotBindQueue
	}

	synlog.Debug("FetchBlock input", "StartHeight", start, "EndHeight", end, "pid", pid)
	blockcount := end - start
	if blockcount < 0 {
		return types.ErrStartBigThanEnd
	}
	var requestblock types.ReqBlocks
	requestblock.Start = start
	requestblock.IsDetail = false
	requestblock.Pid = pid

	//同步block一次请求128个
	if blockcount >= MaxFetchBlockNum {
		requestblock.End = start + MaxFetchBlockNum - 1
	} else {
		requestblock.End = end
	}
	var cb func()
	if syncOrfork {
		//还有区块需要请求，挂接钩子回调函数
		if requestblock.End < chain.forkInfo.ForkEndHeight {
			cb = func() {
				chain.ReqForkBlocks()
			}
			chain.UpdateForkStartHeight(requestblock.End + 1)
		} else { // 所有fork block已请求结束，恢复forkinfo为默认值
			chain.DefaultForkInfo()
		}
		err = chain.forktask.Start(requestblock.Start, requestblock.End, cb)
		if err != nil {
			return err
		}
	} else {
		if chain.GetPeerMaxBlkHeight()-requestblock.End > BackBlockNum {
			cb = func() {
				chain.SynBlocksFromPeers()
			}
		}
		err = chain.task.Start(requestblock.Start, requestblock.End, cb)
		if err != nil {
			return err
		}
	}

	synlog.Debug("FetchBlock", "Start", requestblock.Start, "End", requestblock.End)
	msg := chain.client.NewMessage("p2p", types.EventFetchBlocks, &requestblock)
	Err := chain.client.Send(msg, true)
	if Err != nil {
		synlog.Error("FetchBlock", "client.Send err:", Err)
		return err
	}
	resp, err := chain.client.Wait(msg)
	if err != nil {
		synlog.Error("FetchBlock", "client.Wait err:", err)
		return err
	}
	return resp.Err()
}

//FetchPeerList 从p2p模块获取peerlist，用于获取active链上最新的高度。
//如果没有收到广播block就主动向p2p模块发送请求
func (chain *BlockChain) FetchPeerList() {
	defer chain.tickerwg.Done()
	chain.fetchPeerList()
}

func (chain *BlockChain) fetchPeerList() error {
	if chain.client == nil {
		synlog.Error("fetchPeerList chain client not bind message queue.")
		return nil
	}
	msg := chain.client.NewMessage("p2p", types.EventPeerInfo, nil)
	Err := chain.client.SendTimeout(msg, true, 30*time.Second)
	if Err != nil {
		synlog.Error("fetchPeerList", "client.Send err:", Err)
		return Err
	}
	resp, err := chain.client.WaitTimeout(msg, 60*time.Second)
	if err != nil {
		synlog.Error("fetchPeerList", "client.Wait err:", err)
		return err
	}

	peerlist := resp.GetData().(*types.PeerList)
	if peerlist == nil {
		synlog.Error("fetchPeerList", "peerlist", "is nil")
		return types.ErrNoPeer
	}
	curheigt := chain.GetBlockHeight()

	var peerInfoList PeerInfoList
	for _, peer := range peerlist.Peers {
		//chainlog.Info("fetchPeerList", "peername:", peer.Name, "peerHeight:", peer.Header.Height)

		//过滤掉自己和小于自己5个高度的节点
		if peer.Self || curheigt > peer.Header.Height+5 {
			continue
		}
		var peerInfo PeerInfo
		peerInfo.Name = peer.Name
		peerInfo.ParentHash = peer.Header.ParentHash
		peerInfo.Height = peer.Header.Height
		peerInfo.Hash = peer.Header.Hash
		peerInfoList = append(peerInfoList, &peerInfo)
	}
	//peerlist中没有比自己节点高的就不做处理直接返回
	if len(peerInfoList) == 0 {
		return nil
	}
	//按照height给peer排序从小到大
	sort.Sort(peerInfoList)

	subInfoList := peerInfoList

	peerMaxBlklock.Lock()
	chain.peerList = subInfoList
	peerMaxBlklock.Unlock()

	//获取到peerlist之后，需要判断是否已经发起了最优链的检测。如果没有就触发一次最优链的检测
	if atomic.LoadInt32(&chain.firstcheckbestchain) == 0 {
		synlog.Info("fetchPeerList trigger first CheckBestChain")
		chain.CheckBestChain(true)
	}
	return nil
}

//GetRcvLastCastBlkHeight 存储广播的block最新高度
func (chain *BlockChain) GetRcvLastCastBlkHeight() int64 {
	castlock.Lock()
	defer castlock.Unlock()
	return chain.rcvLastBlockHeight
}

//UpdateRcvCastBlkHeight 更新广播的block最新高度
func (chain *BlockChain) UpdateRcvCastBlkHeight(height int64) {
	castlock.Lock()
	defer castlock.Unlock()
	chain.rcvLastBlockHeight = height
}

//GetsynBlkHeight 存储已经同步到db的block高度
func (chain *BlockChain) GetsynBlkHeight() int64 {
	synBlocklock.Lock()
	defer synBlocklock.Unlock()
	return chain.synBlockHeight
}

//UpdatesynBlkHeight 更新已经同步到db的block高度
func (chain *BlockChain) UpdatesynBlkHeight(height int64) {
	synBlocklock.Lock()
	defer synBlocklock.Unlock()
	chain.synBlockHeight = height
}

//GetPeerMaxBlkHeight 获取peerlist中合法的最新block高度
func (chain *BlockChain) GetPeerMaxBlkHeight() int64 {
	peerMaxBlklock.Lock()
	defer peerMaxBlklock.Unlock()

	//获取peerlist中最高的高度，peerlist是已经按照高度排序了的。
	if chain.peerList != nil {
		peerlen := len(chain.peerList)
		for i := peerlen - 1; i >= 0; i-- {
			if chain.peerList[i] != nil {
				ok := chain.IsFaultPeer(chain.peerList[i].Name)
				if !ok {
					return chain.peerList[i].Height
				}
			}
		}
		//没有合法的peer，此时本节点可能在侧链上，返回peerlist中最高的peer尝试矫正
		maxpeer := chain.peerList[peerlen-1]
		if maxpeer != nil {
			synlog.Debug("GetPeerMaxBlkHeight all peers are faultpeer maybe self on Side chain", "pid", maxpeer.Name, "Height", maxpeer.Height, "Hash", common.ToHex(maxpeer.Hash))
			return maxpeer.Height
		}
	}
	return -1
}

//GetPeerInfo 通过peerid获取peerinfo
func (chain *BlockChain) GetPeerInfo(pid string) *PeerInfo {
	peerMaxBlklock.Lock()
	defer peerMaxBlklock.Unlock()

	//获取peerinfo
	if chain.peerList != nil {
		for _, peer := range chain.peerList {
			if pid == peer.Name {
				return peer
			}
		}
	}
	return nil
}

//GetMaxPeerInfo 获取peerlist中最高节点的peerinfo
func (chain *BlockChain) GetMaxPeerInfo() *PeerInfo {
	peerMaxBlklock.Lock()
	defer peerMaxBlklock.Unlock()

	//获取peerlist中高度最高的peer，peerlist是已经按照高度排序了的。
	if chain.peerList != nil {
		peerlen := len(chain.peerList)
		for i := peerlen - 1; i >= 0; i-- {
			if chain.peerList[i] != nil {
				ok := chain.IsFaultPeer(chain.peerList[i].Name)
				if !ok {
					return chain.peerList[i]
				}
			}
		}
		//没有合法的peer，此时本节点可能在侧链上，返回peerlist中最高的peer尝试矫正
		maxpeer := chain.peerList[peerlen-1]
		if maxpeer != nil {
			synlog.Debug("GetMaxPeerInfo all peers are faultpeer maybe self on Side chain", "pid", maxpeer.Name, "Height", maxpeer.Height, "Hash", common.ToHex(maxpeer.Hash))
			return maxpeer
		}
	}
	return nil
}

//GetPeers 获取所有peers
func (chain *BlockChain) GetPeers() PeerInfoList {
	peerMaxBlklock.Lock()
	defer peerMaxBlklock.Unlock()

	//获取peerinfo
	var peers PeerInfoList

	if chain.peerList != nil {
		peers = append(peers, chain.peerList...)
	}
	return peers
}

//IsFaultPeer 判断指定pid是否在故障faultPeerList中
func (chain *BlockChain) IsFaultPeer(pid string) bool {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()

	return chain.faultPeerList[pid] != nil
}

//IsErrExecBlock 判断此block是否被记录在本节点执行错误。
func (chain *BlockChain) IsErrExecBlock(height int64, hash []byte) (bool, error) {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()

	//循环遍历故障peerlist，尝试检测故障peer是否已经恢复
	for _, faultpeer := range chain.faultPeerList {
		if faultpeer.FaultHeight == height && bytes.Equal(hash, faultpeer.FaultHash) {
			return true, faultpeer.ErrInfo
		}
	}
	return false, nil
}

//GetFaultPeer 获取指定pid是否在故障faultPeerList中
func (chain *BlockChain) GetFaultPeer(pid string) *FaultPeerInfo {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()

	return chain.faultPeerList[pid]
}

//RecoveryFaultPeer 尝试恢复故障peer节点，定时从出错的peer获取出错block的头信息。
//看对应的block是否有更新。有更新就说明故障peer节点已经恢复ok
func (chain *BlockChain) RecoveryFaultPeer() {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()

	defer chain.tickerwg.Done()

	//循环遍历故障peerlist，尝试检测故障peer是否已经恢复
	for pid, faultpeer := range chain.faultPeerList {
		//需要考虑回退的情况，可能本地节点已经回退，恢复以前的故障节点，获取故障高度的区块的hash是否在本地已经校验通过。校验通过就直接说明故障已经恢复
		//获取本节点指定高度的blockhash做判断，hash相同就确认故障已经恢复
		blockhash, err := chain.blockStore.GetBlockHashByHeight(faultpeer.FaultHeight)
		if err == nil {
			if bytes.Equal(faultpeer.FaultHash, blockhash) {
				synlog.Debug("RecoveryFaultPeer ", "Height", faultpeer.FaultHeight, "FaultHash", common.ToHex(faultpeer.FaultHash), "pid", pid)
				delete(chain.faultPeerList, pid)
				continue
			}
		}

		chain.FetchBlockHeaders(faultpeer.FaultHeight, faultpeer.FaultHeight, pid)
		chain.faultPeerList[pid].ReqFlag = true
		synlog.Debug("RecoveryFaultPeer", "pid", faultpeer.Peer.Name, "FaultHeight", faultpeer.FaultHeight, "FaultHash", common.ToHex(faultpeer.FaultHash), "Err", faultpeer.ErrInfo)
	}
}

//AddFaultPeer 添加故障节点到故障FaultPeerList中
func (chain *BlockChain) AddFaultPeer(faultpeer *FaultPeerInfo) {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()

	//此节点已经存在故障peerlist中打印信息
	faultnode := chain.faultPeerList[faultpeer.Peer.Name]
	if faultnode != nil {
		synlog.Debug("AddFaultPeer old", "pid", faultnode.Peer.Name, "FaultHeight", faultnode.FaultHeight, "FaultHash", common.ToHex(faultnode.FaultHash), "Err", faultnode.ErrInfo)
	}
	chain.faultPeerList[faultpeer.Peer.Name] = faultpeer
	synlog.Debug("AddFaultPeer new", "pid", faultpeer.Peer.Name, "FaultHeight", faultpeer.FaultHeight, "FaultHash", common.ToHex(faultpeer.FaultHash), "Err", faultpeer.ErrInfo)
}

//RemoveFaultPeer 此pid对应的故障已经修复，将此pid从故障列表中移除
func (chain *BlockChain) RemoveFaultPeer(pid string) {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()
	synlog.Debug("RemoveFaultPeer", "pid", pid)

	delete(chain.faultPeerList, pid)
}

//UpdateFaultPeer 更新此故障peer的请求标志位
func (chain *BlockChain) UpdateFaultPeer(pid string, reqFlag bool) {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()

	faultpeer := chain.faultPeerList[pid]
	if faultpeer != nil {
		faultpeer.ReqFlag = reqFlag
	}
}

//RecordFaultPeer 当blcok执行出错时，记录出错block高度，hash值，以及出错信息和对应的peerid
func (chain *BlockChain) RecordFaultPeer(pid string, height int64, hash []byte, err error) {

	var faultnode FaultPeerInfo

	//通过pid获取peerinfo
	peerinfo := chain.GetPeerInfo(pid)
	if peerinfo == nil {
		synlog.Error("RecordFaultPeerNode GetPeerInfo is nil", "pid", pid)
		return
	}
	faultnode.Peer = peerinfo
	faultnode.FaultHeight = height
	faultnode.FaultHash = hash
	faultnode.ErrInfo = err
	faultnode.ReqFlag = false
	chain.AddFaultPeer(&faultnode)
}

//PrintFaultPeer 打印出错的节点
func (chain *BlockChain) PrintFaultPeer() {
	faultpeerlock.Lock()
	defer faultpeerlock.Unlock()

	//循环遍历故障peerlist，尝试检测故障peer是否已经恢复
	for pid, faultpeer := range chain.faultPeerList {
		synlog.Debug("PrintFaultPeer", "pid", pid, "FaultHeight", faultpeer.FaultHeight, "FaultHash", common.ToHex(faultpeer.FaultHash), "Err", faultpeer.ErrInfo)
	}
}

//SynBlocksFromPeers blockSynSeconds时间检测一次本节点的height是否有增长，没有增长就需要通过对端peerlist获取最新高度，发起同步
func (chain *BlockChain) SynBlocksFromPeers() {

	curheight := chain.GetBlockHeight()
	RcvLastCastBlkHeight := chain.GetRcvLastCastBlkHeight()
	peerMaxBlkHeight := chain.GetPeerMaxBlkHeight()

	// 节点同步阶段自己高度小于最大高度batchsyncblocknum时存储block到db批量处理时不刷盘
	if peerMaxBlkHeight > curheight+batchsyncblocknum && !chain.cfgBatchSync {
		atomic.CompareAndSwapInt32(&chain.isbatchsync, 1, 0)
	} else {
		atomic.CompareAndSwapInt32(&chain.isbatchsync, 0, 1)
	}
	//synlog.Info("SynBlocksFromPeers", "isbatchsync", chain.isbatchsync)

	//如果任务正常，那么不重复启动任务
	if chain.task.InProgress() {
		synlog.Info("chain task InProgress")
		return
	}
	//获取peers的最新高度.处理没有收到广播block的情况
	if curheight+1 < peerMaxBlkHeight {
		synlog.Info("SynBlocksFromPeers", "curheight", curheight, "LastCastBlkHeight", RcvLastCastBlkHeight, "peerMaxBlkHeight", peerMaxBlkHeight)
		pids := chain.GetBestChainPids()
		if pids != nil {
			chain.FetchBlock(curheight+1, peerMaxBlkHeight, pids, false)
		} else {
			synlog.Info("SynBlocksFromPeers GetBestChainPids is nil")
		}
	}
}

//CheckHeightNoIncrease 在规定时间本链的高度没有增长，但peerlist中最新高度远远高于本节点高度，
//可能当前链是在分支链上,需从指定最长链的peer向后请求指定数量的blockheader
//请求bestchain.Height -BackBlockNum -- bestchain.Height的header
//需要考虑收不到分叉之后的第一个广播block，这样就会导致后面的广播block都在孤儿节点中了。
func (chain *BlockChain) CheckHeightNoIncrease() {
	synlog.Debug("CheckHeightNoIncrease")
	defer chain.tickerwg.Done()

	//获取当前主链的最新高度
	tipheight := chain.bestChain.Height()
	laststorheight := chain.blockStore.Height()

	if tipheight != laststorheight {
		synlog.Error("CheckHeightNoIncrease", "tipheight", tipheight, "laststorheight", laststorheight)
		return
	}
	//获取上个检测周期时的检测高度
	checkheight := chain.GetsynBlkHeight()

	//bestchain的tip高度在变化，更新最新的检测高度即可，高度可能在增长或者回退
	if tipheight != checkheight {
		chain.UpdatesynBlkHeight(tipheight)
		return
	}
	//一个检测周期bestchain的tip高度没有变化。并且远远落后于peer的最新高度
	//本节点可能在侧链上，需要从最新的peer上向后取BackBlockNum个headers

	maxpeer := chain.GetMaxPeerInfo()
	if maxpeer == nil {
		synlog.Error("CheckHeightNoIncrease GetMaxPeerInfo is nil")
		return
	}
	peermaxheight := maxpeer.Height
	pid := maxpeer.Name

	if peermaxheight > tipheight && (peermaxheight-tipheight) > BackwardBlockNum {
		//从指定peer 请求BackBlockNum个blockheaders
		if tipheight > BackBlockNum {
			chain.FetchBlockHeaders(tipheight-BackBlockNum, tipheight, pid)
		} else {
			chain.FetchBlockHeaders(0, tipheight, pid)
		}
	}
}

//FetchBlockHeaders 从指定pid获取start到end之间的headers
func (chain *BlockChain) FetchBlockHeaders(start int64, end int64, pid string) (err error) {
	if chain.client == nil {
		synlog.Error("FetchBlockHeaders chain client not bind message queue.")
		return types.ErrClientNotBindQueue
	}

	chainlog.Debug("FetchBlockHeaders", "StartHeight", start, "EndHeight", end, "pid", pid)

	var requestblock types.ReqBlocks
	requestblock.Start = start
	requestblock.End = end
	requestblock.IsDetail = false
	requestblock.Pid = []string{pid}

	msg := chain.client.NewMessage("p2p", types.EventFetchBlockHeaders, &requestblock)
	Err := chain.client.Send(msg, true)
	if Err != nil {
		synlog.Error("FetchBlockHeaders", "client.Send err:", Err)
		return err
	}
	resp, err := chain.client.Wait(msg)
	if err != nil {
		synlog.Error("FetchBlockHeaders", "client.Wait err:", err)
		return err
	}
	return resp.Err()
}

//ProcBlockHeader 一个block header消息的处理，分tiphash的校验，故障peer的故障block是否恢复的校验
func (chain *BlockChain) ProcBlockHeader(headers *types.Headers, peerid string) error {

	//判断是否是用于检测故障peer而请求的block header
	faultPeer := chain.GetFaultPeer(peerid)
	if faultPeer != nil && faultPeer.ReqFlag && faultPeer.FaultHeight == headers.Items[0].Height {
		//同一高度的block hash有更新，表示故障peer的故障已经恢复，将此peer从故障peerlist中移除
		if !bytes.Equal(headers.Items[0].Hash, faultPeer.FaultHash) {
			chain.RemoveFaultPeer(peerid)
		} else {
			chain.UpdateFaultPeer(peerid, false)
		}
		return nil
	}

	//检测最优链的处理
	bestchainPeer := chain.GetBestChainPeer(peerid)
	if bestchainPeer != nil && bestchainPeer.ReqFlag && headers.Items[0].Height == bestchainPeer.Height {
		chain.CheckBestChainProc(headers, peerid)
		return nil
	}

	// 用于tiphash对比而请求的block header
	height := headers.Items[0].Height
	//获取height高度在本节点的headers信息
	header, err := chain.blockStore.GetBlockHeaderByHeight(height)
	if err != nil {
		return err
	}
	//对应高度hash不相等就向后寻找分叉点
	if !bytes.Equal(headers.Items[0].Hash, header.Hash) {
		synlog.Info("ProcBlockHeader hash no equal", "height", height, "self hash", common.ToHex(header.Hash), "peer hash", common.ToHex(headers.Items[0].Hash))

		if height > BackBlockNum {
			chain.FetchBlockHeaders(height-BackBlockNum, height, peerid)
		} else if height != 0 {
			chain.FetchBlockHeaders(0, height, peerid)
		}
	}
	return nil
}

//ProcBlockHeaders 多个headers消息的处理，主要用于寻找分叉节点
func (chain *BlockChain) ProcBlockHeaders(headers *types.Headers, pid string) error {
	var ForkHeight int64 = -1
	var forkhash []byte
	count := len(headers.Items)
	tipheight := chain.bestChain.Height()

	//循环找到分叉点
	for i := count - 1; i >= 0; i-- {
		exists := chain.bestChain.HaveBlock(headers.Items[i].Hash, headers.Items[i].Height)
		if exists {
			ForkHeight = headers.Items[i].Height
			forkhash = headers.Items[i].Hash
			break
		}
	}
	if ForkHeight == -1 {
		synlog.Error("ProcBlockHeaders do not find fork point ")
		synlog.Error("ProcBlockHeaders start headerinfo", "height", headers.Items[0].Height, "hash", common.ToHex(headers.Items[0].Hash))
		synlog.Error("ProcBlockHeaders end headerinfo", "height", headers.Items[count-1].Height, "hash", common.ToHex(headers.Items[count-1].Hash))

		//回退5000个block之后不再回退了，直接返回错误
		startheight := headers.Items[0].Height
		if tipheight > startheight && (tipheight-startheight) > MaxRollBlockNum {
			synlog.Error("ProcBlockHeaders Not Roll Back!", "selfheight", tipheight, "RollBackedhieght", startheight)
			return types.ErrNotRollBack
		}
		//继续向后取指定数量的headers
		height := headers.Items[0].Height
		if height > BackBlockNum {
			chain.FetchBlockHeaders(height-BackBlockNum, height, pid)
		} else {
			chain.FetchBlockHeaders(0, height, pid)
		}
		return types.ErrContinueBack
	}
	synlog.Info("ProcBlockHeaders find fork point", "height", ForkHeight, "hash", common.ToHex(forkhash))

	//获取此pid对应的peer信息，
	peerinfo := chain.GetPeerInfo(pid)
	if peerinfo == nil {
		synlog.Error("ProcBlockHeaders GetPeerInfo is nil", "pid", pid)
		return types.ErrPeerInfoIsNil
	}

	//从分叉节点高度继续请求block，从pid
	peermaxheight := peerinfo.Height

	//启动一个线程在后台获取分叉的blcok
	if chain.forktask.InProgress() {
		synlog.Info("ProcBlockHeaders forktask.InProgress")
		return nil
	}
	go chain.ProcBlockChainFork(ForkHeight, peermaxheight, pid)
	return nil
}

//ProcBlockChainFork 处理从peer获取的headers消息
func (chain *BlockChain) ProcBlockChainFork(forkStartHeight int64, forkEndHeight int64, pid string) {
	forkinfo := chain.GetForkInfo()

	//可能存在上次fork 处理过程中下载区块超时，forktask任务退出，但forkinfo没有恢复成默认值
	if forkinfo.ForkStartHeight != -1 || forkinfo.ForkEndHeight != -1 {
		synlog.Error("ProcBlockChainFork Fork processing", "pid", forkinfo.ForkPid, "ForkStartHeight", forkinfo.ForkStartHeight, "ForkEndHeight", forkinfo.ForkEndHeight)
	}

	chain.DefaultForkInfo()
	chain.InitForkInfo(forkStartHeight, forkEndHeight, pid)
	chain.ReqForkBlocks()
}

//InitForkInfo 开始新的fork处理
func (chain *BlockChain) InitForkInfo(forkStartHeight int64, forkEndHeight int64, pid string) {
	chain.forklock.Lock()
	defer chain.forklock.Unlock()

	chain.forkInfo.ForkStartHeight = forkStartHeight
	chain.forkInfo.ForkEndHeight = forkEndHeight
	chain.forkInfo.ForkPid = pid
	synlog.Debug("InitForkInfo Fork process begin", "ForkStartHeight", forkStartHeight, "ForkEndHeight", forkEndHeight, "pid", pid)

}

//DefaultForkInfo 将forkinfo恢复成默认值
func (chain *BlockChain) DefaultForkInfo() {
	chain.forklock.Lock()
	defer chain.forklock.Unlock()

	chain.forkInfo.ForkStartHeight = -1
	chain.forkInfo.ForkEndHeight = -1
	chain.forkInfo.ForkPid = ""
	synlog.Debug("DefaultForkInfo")
}

//GetForkInfo 获取forkinfo
func (chain *BlockChain) GetForkInfo() *ForkInfo {
	chain.forklock.Lock()
	defer chain.forklock.Unlock()

	return chain.forkInfo
}

//UpdateForkStartHeight 更新fork 请求的起始block高度
func (chain *BlockChain) UpdateForkStartHeight(forkStartHeight int64) {
	chain.forklock.Lock()
	defer chain.forklock.Unlock()

	chain.forkInfo.ForkStartHeight = forkStartHeight
	synlog.Debug("UpdateForkStartHeight", "ForkStartHeight", chain.forkInfo.ForkStartHeight, "ForkEndHeight", chain.forkInfo.ForkEndHeight, "pid", chain.forkInfo.ForkPid)
}

//ReqForkBlocks 请求fork处理的blocks
func (chain *BlockChain) ReqForkBlocks() {
	forkinfo := chain.GetForkInfo()
	if forkinfo.ForkStartHeight != -1 && forkinfo.ForkEndHeight != -1 && forkinfo.ForkPid != "" {
		synlog.Info("ReqForkBlocks", "ForkStartHeight", forkinfo.ForkStartHeight, "ForkEndHeight", forkinfo.ForkEndHeight, "pid", forkinfo.ForkPid)
		chain.FetchBlock(forkinfo.ForkStartHeight, forkinfo.ForkEndHeight, []string{forkinfo.ForkPid}, true)
	}
}

//ProcAddBlockHeadersMsg 处理从peer获取的headers消息
func (chain *BlockChain) ProcAddBlockHeadersMsg(headers *types.Headers, pid string) error {
	if headers == nil {
		return types.ErrInvalidParam
	}
	count := len(headers.Items)
	synlog.Debug("ProcAddBlockHeadersMsg", "count", count, "pid", pid)
	if count == 1 {
		return chain.ProcBlockHeader(headers, pid)
	}
	return chain.ProcBlockHeaders(headers, pid)

}

//CheckTipBlockHash 在规定时间本链的高度没有增长，但peerlist中最新高度远远高于本节点高度，
//可能当前链是在分支链上,需从指定最长链的peer向后请求指定数量的blockheader
//请求bestchain.Height -BackBlockNum -- bestchain.Height的header
//需要考虑收不到分叉之后的第一个广播block，这样就会导致后面的广播block都在孤儿节点中了。
func (chain *BlockChain) CheckTipBlockHash() {
	synlog.Debug("CheckTipBlockHash")
	defer chain.tickerwg.Done()

	//获取当前主链的高度
	tipheight := chain.bestChain.Height()
	tiphash := chain.bestChain.Tip().hash
	laststorheight := chain.blockStore.Height()

	if tipheight != laststorheight {
		synlog.Error("CheckTipBlockHash", "tipheight", tipheight, "laststorheight", laststorheight)
		return
	}

	maxpeer := chain.GetMaxPeerInfo()
	if maxpeer == nil {
		synlog.Error("CheckTipBlockHash GetMaxPeerInfo is nil")
		return
	}
	peermaxheight := maxpeer.Height
	pid := maxpeer.Name
	peerhash := maxpeer.Hash

	//和最高的peer做tip block hash的校验
	if peermaxheight > tipheight {
		//从指定peer 请求BackBlockNum个blockheaders
		synlog.Debug("CheckTipBlockHash >", "peermaxheight", peermaxheight, "tipheight", tipheight)
		chain.FetchBlockHeaders(tipheight, tipheight, pid)
	} else if peermaxheight == tipheight {
		// 直接tip block hash比较,如果不相等需要从peer向后去指定的headers，尝试寻找分叉点
		if !bytes.Equal(tiphash, peerhash) {
			if tipheight > BackBlockNum {
				synlog.Debug("CheckTipBlockHash ==", "peermaxheight", peermaxheight, "tipheight", tipheight)
				chain.FetchBlockHeaders(tipheight-BackBlockNum, tipheight, pid)
			} else {
				synlog.Debug("CheckTipBlockHash !=", "peermaxheight", peermaxheight, "tipheight", tipheight)
				chain.FetchBlockHeaders(1, tipheight, pid)
			}
		}
	} else {

		header, err := chain.blockStore.GetBlockHeaderByHeight(peermaxheight)
		if err != nil {
			return
		}
		if !bytes.Equal(header.Hash, peerhash) {
			if peermaxheight > BackBlockNum {
				synlog.Debug("CheckTipBlockHash<!=", "peermaxheight", peermaxheight, "tipheight", tipheight)
				chain.FetchBlockHeaders(peermaxheight-BackBlockNum, peermaxheight, pid)
			} else {
				synlog.Debug("CheckTipBlockHash<!=", "peermaxheight", peermaxheight, "tipheight", tipheight)
				chain.FetchBlockHeaders(1, peermaxheight, pid)
			}
		}
	}
}

//IsCaughtUp 本节点是否已经追赶上主链高度，追赶上之后通知本节点的共识模块开始挖矿
func (chain *BlockChain) IsCaughtUp() bool {

	height := chain.GetBlockHeight()

	//peerMaxBlklock.Lock()
	//defer peerMaxBlklock.Unlock()
	peers := chain.GetPeers()
	// peer中只有自己节点，没有其他节点
	if peers == nil {
		synlog.Debug("IsCaughtUp has no peers")
		return chain.cfg.SingleMode
	}

	var maxPeerHeight int64 = -1
	peersNo := 0
	for _, peer := range peers {
		if peer != nil && maxPeerHeight < peer.Height {
			ok := chain.IsFaultPeer(peer.Name)
			if !ok {
				maxPeerHeight = peer.Height
			}
		}
		peersNo++
	}

	isCaughtUp := (height > 0 || types.Since(chain.startTime) > 60*time.Second) && (maxPeerHeight == 0 || (height >= maxPeerHeight && maxPeerHeight != -1))

	synlog.Debug("IsCaughtUp", "IsCaughtUp ", isCaughtUp, "height", height, "maxPeerHeight", maxPeerHeight, "peersNo", peersNo)
	return isCaughtUp
}

//GetNtpClockSyncStatus 获取ntp时间是否同步状态
func GetNtpClockSyncStatus() bool {
	ntpClockSynclock.Lock()
	defer ntpClockSynclock.Unlock()
	return isNtpClockSync
}

//UpdateNtpClockSyncStatus 定时更新ntp时间同步状态
func UpdateNtpClockSyncStatus(Sync bool) {
	ntpClockSynclock.Lock()
	defer ntpClockSynclock.Unlock()
	isNtpClockSync = Sync
}

//CheckBestChain 定时确保本节点在最优链上,定时向peer请求指定高度的header
func (chain *BlockChain) CheckBestChain(isFirst bool) {
	if !isFirst {
		defer chain.tickerwg.Done()
	}
	peers := chain.GetPeers()
	// peer中只有自己节点，没有其他节点
	if peers == nil {
		synlog.Debug("CheckBestChain has no peers")
		return
	}

	//设置首次检测最优链的标志
	atomic.CompareAndSwapInt32(&chain.firstcheckbestchain, 0, 1)

	tipheight := chain.bestChain.Height()

	bestpeerlock.Lock()
	defer bestpeerlock.Unlock()

	for _, peer := range peers {
		bestpeer := chain.bestChainPeerList[peer.Name]
		if bestpeer != nil {
			bestpeer.Peer = peer
			bestpeer.Height = tipheight
			bestpeer.Hash = nil
			bestpeer.Td = nil
			bestpeer.ReqFlag = true
		} else {
			if peer.Height < tipheight {
				continue
			}
			var newbestpeer BestPeerInfo
			newbestpeer.Peer = peer
			newbestpeer.Height = tipheight
			newbestpeer.Hash = nil
			newbestpeer.Td = nil
			newbestpeer.ReqFlag = true
			newbestpeer.IsBestChain = false
			chain.bestChainPeerList[peer.Name] = &newbestpeer
		}
		synlog.Debug("CheckBestChain FetchBlockHeaders", "height", tipheight, "pid", peer.Name)
		chain.FetchBlockHeaders(tipheight, tipheight, peer.Name)
	}
}

//GetBestChainPeer 获取最优节点
func (chain *BlockChain) GetBestChainPeer(pid string) *BestPeerInfo {
	bestpeerlock.Lock()
	defer bestpeerlock.Unlock()
	return chain.bestChainPeerList[pid]
}

//GetBestChainPids 定时确保本节点在最优链上,定时向peer请求指定高度的header
func (chain *BlockChain) GetBestChainPids() []string {
	var PeerPids []string
	bestpeerlock.Lock()
	defer bestpeerlock.Unlock()

	for key, value := range chain.bestChainPeerList {
		if value.IsBestChain {
			ok := chain.IsFaultPeer(value.Peer.Name)
			if !ok {
				PeerPids = append(PeerPids, key)
			}
		}
	}
	synlog.Debug("GetBestChainPids ", "pids", PeerPids)
	return PeerPids
}

//CheckBestChainProc 检查最优链
func (chain *BlockChain) CheckBestChainProc(headers *types.Headers, pid string) {

	//获取本节点指定高度的blockhash
	blockhash, err := chain.blockStore.GetBlockHashByHeight(headers.Items[0].Height)
	if err != nil {
		synlog.Debug("CheckBestChainProc GetBlockHashByHeight", "Height", headers.Items[0].Height, "err", err)
		return
	}

	bestpeerlock.Lock()
	defer bestpeerlock.Unlock()

	bestchainpeer := chain.bestChainPeerList[pid]
	if bestchainpeer == nil {
		synlog.Debug("CheckBestChainProc bestChainPeerList is nil", "Height", headers.Items[0].Height, "pid", pid)
		return
	}
	//
	if bestchainpeer.Height == headers.Items[0].Height {
		bestchainpeer.Hash = headers.Items[0].Hash
		bestchainpeer.ReqFlag = false
		if bytes.Equal(headers.Items[0].Hash, blockhash) {
			bestchainpeer.IsBestChain = true
			synlog.Debug("CheckBestChainProc IsBestChain ", "Height", headers.Items[0].Height, "pid", pid)
		} else {
			bestchainpeer.IsBestChain = false
			synlog.Debug("CheckBestChainProc NotBestChain", "Height", headers.Items[0].Height, "pid", pid)
		}
	}
}