/*
 * 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 syncdb

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"github.com/hashicorp/memberlist"
	"net"
	"strconv"

	"time"

	"basic.com/valib/serf.git/cmd/serf/command/agent"
	"basic.com/valib/serf.git/serf"
	//"github.com/apache/servicecomb-service-center/pkg/log"
	"basic.com/valib/logger.git"
)

// Agent warps the serf agent
type Agent struct {
	*agent.Agent
	ipc *agent.AgentIPC
	conf     	*Config
	readyCh  	chan struct{}
	errorCh  	chan error
	handleEv 	HandleEventFunc
}

//用户自定义事件处理
type HandleEventFunc func(event serf.Event)

type NodeInfo struct {
	ClusterID   		string 		`json:"clusterID"`
	NodeID      		string 		`json:"nodeID"`
	NodeAddress 		string 		`json:"nodeAddress"`
	IsAlive     		int    		`json:"isAlive"`
}

// Create create serf agent with config
func Create(conf *Config, snapshotPath string) (*Agent, error) {
	// config cover to serf config
	serfConf, err := conf.convertToSerf(snapshotPath)
	if err != nil {
		return nil, err
	}

	// create serf agent with serf config
	logger.Info("conf.Config.EncryptKey:", conf.EncryptKey)
	serfAgent, err := agent.Create(conf.Config, serfConf, logger.GetLogFile())
	if err != nil {
		return nil, err
	}
	// Create the keyring
	keyring, err := memberlist.NewKeyring(nil, []byte(conf.EncryptKey))
	if err != nil {
		logger.Error("Failed to restore keyring: %s", err)
		return nil, err
	}
	serfConf.MemberlistConfig.Keyring = keyring

	logger.Info("[INFO] agent: Restored keyring with %d keys from %s",
		len(conf.EncryptKey), conf.EncryptKey)

	return &Agent{
		Agent:   serfAgent,
		conf:    conf,
		readyCh: make(chan struct{}),
		errorCh: make(chan error),
	}, nil
}

func (a *Agent) RegisterHandleEventFunc(f HandleEventFunc) {
	if f != nil {
		a.handleEv = f
	}
}

// Start agent and IPC
func (a *Agent) Start(ctx context.Context) {
	a.RegisterEventHandler(a)
	err := a.Agent.Start()
	if err != nil {
		logger.Error(err, "start serf agent failed")
		a.errorCh <- err
		return
	}

	ipc := a.startIPC()
	a.ipc = ipc
	go func() {
		for {
			select {
			case <-ctx.Done():
				a.Agent.Shutdown()
				a.ipc.Shutdown()
				return
			default:
				time.Sleep(1*time.Second)
			}
		}
	}()

	err = a.retryJoin(ctx)
	if err != nil {
		logger.Error(err, "start serf agent failed")
		if err != ctx.Err() && a.errorCh != nil {
			a.errorCh <- err
		}
	}

	go a.BroadcastMemberlist(BroadcastInterval * time.Second)
}

func (a *Agent) startIPC() *agent.AgentIPC {
	// Parse the bind address information
	bindIP, bindPort, err := a.conf.AddrParts(a.conf.BindAddr)
	bindAddr := &net.TCPAddr{IP: net.ParseIP(bindIP), Port: bindPort}

	// Setup the RPC listener
	rpcListener, err := net.Listen("tcp", a.conf.RPCAddr)
	if err != nil {
		logger.Error("Error starting RPC listener:", err)
		return nil
	}
	ipc := agent.NewAgentIPC(a.Agent, a.conf.RPCAuthKey, rpcListener, logger.GetLogFile(), nil)
	logger.Debug("RPC addr:", a.conf.RPCAddr)
	logger.Debug("Snapshot:", a.conf.SnapshotPath)
	logger.Debug("Profile:", a.conf.Profile)
	logger.Debug("Message Compression Enabled:", a.conf.EnableCompression)
	logger.Debug("bindAddr:", bindAddr)
	return ipc
}
// HandleEvent Handles serf.EventMemberJoin events,
// which will wait for members to join until the number of group members is equal to "groupExpect"
// when the startup mode is "ModeCluster",
// used for logical grouping of serf nodes
func (a *Agent) HandleEvent(event serf.Event) {
	if a.handleEv != nil {
		a.handleEv(event)
	}
}


func (a *Agent) BroadcastMemberlist(delay time.Duration) {
	//serf := a.serf
	serf := a.Agent.Serf()
	mb := serf.LocalMember()
	mblist := serf.Memberlist()
	logger.Info("mb:", mb)

	// copy local node
	localNode := *mblist.LocalNode()
	nodeID := a.conf.NodeName
	nodeAddress := localNode.Address()
	clusterID := mb.Tags[tagKeyClusterID]
	isAlive := int(mb.Status)

	message, _ := json.Marshal(NodeInfo{
		clusterID,
		nodeID,
		nodeAddress,
		isAlive,
	})

	// replace node address
	localNode.Addr = net.ParseIP(BroadcastIP)
	//localNode.Addr = net.IPv4(255,255,255,255)
	localNode.Port = BroadcastPort
	for {
		// logger.Info("localNode: %v %v\n", nodeName, nodeAddress)
		mblist.SendBestEffort(&localNode, []byte(message))
		time.Sleep(delay)
	}
}

// Ready Returns a channel that will be closed when serf is ready
func (a *Agent) Ready() <-chan struct{} {
	return a.readyCh
}

// Error Returns a channel that will be transmit a serf error
func (a *Agent) Error() <-chan error {
	return a.errorCh
}

// Stop serf agent
func (a *Agent) Stop() {
	if a.errorCh != nil {
		logger.Info("a.Shutdown()", a.Leave())
		logger.Info("a.Shutdown()", a.Shutdown())
		close(a.errorCh)
		a.errorCh = nil
	}
}

// LocalMember returns the Member information for the local node
func (a *Agent) LocalMember() *serf.Member {
	serfAgent := a.Agent.Serf()
	if serfAgent != nil {
		member := serfAgent.LocalMember()
		return &member
	}
	return nil
}

// GroupMembers returns a point-in-time snapshot of the members of by clusterID
func (a *Agent) GroupMembers(clusterID string) (members []serf.Member) {
	serfAgent := a.Agent.Serf()
	if serfAgent != nil {
		for _, member := range serfAgent.Members() {
			logger.Info("member = %s, clusterID = %s", member.Name, member.Tags[tagKeyClusterID])
			if member.Tags[tagKeyClusterID] == clusterID {
				members = append(members, member)
			}
		}
	}
	return
}

// Member get member information with node
func (a *Agent) Member(node string) *serf.Member {
	serfAgent := a.Agent.Serf()
	if serfAgent != nil {
		ms := serfAgent.Members()
		for _, m := range ms {
			if m.Name == node {
				return &m
			}
		}
	}
	return nil
}

// SerfConfig get serf config
func (a *Agent) SerfConfig() *serf.Config {
	return a.Agent.SerfConfig()
}

// Join serf clusters through one or more members
func (a *Agent) Join(addrs []string, replay bool) (n int, err error) {
	return a.Agent.Join(addrs, replay)
}

// UserEvent sends a UserEvent on Serf
func (a *Agent) UserEvent(name string, payload []byte, coalesce bool) error {
	return a.Agent.UserEvent(name, payload, coalesce)
}

// Query sends a Query on Serf
func (a *Agent) Query(name string, payload []byte, params *serf.QueryParam) (*serf.QueryResponse, error) {
	return a.Agent.Query(name, payload, params)
}

func (a *Agent) retryJoin(ctx context.Context) (err error) {
	if len(a.conf.RetryJoin) == 0 {
		logger.Error("retry join mumber %d", len(a.conf.RetryJoin))
		return nil
	}

	// Count of attempts
	attempt := 0
	ticker := time.NewTicker(a.conf.RetryInterval)
	for {
		logger.Info("serf: Joining cluster...(replay: %v)", a.conf.ReplayOnJoin)
		var n int

		// Try to join the specified serf nodes
		n, err = a.Join(a.conf.RetryJoin, a.conf.ReplayOnJoin)
		if err == nil {
			logger.Error("serf: Join completed. Synced with %d initial agents", n)
			break
		}
		attempt++

		// If RetryMaxAttempts is greater than 0, agent will exit
		// and throw an error when the number of attempts exceeds RetryMaxAttempts,
		// else agent will try to join other nodes until successful always
		if a.conf.RetryMaxAttempts > 0 && attempt > a.conf.RetryMaxAttempts {
			err = errors.New("serf: maximum retry join attempts made, exiting")
			logger.Error(err, err.Error())
			break
		}
		select {
		case <-ctx.Done():
			err = ctx.Err()
			goto done
		// Waiting for ticker to trigger
		case <-ticker.C:
		}
	}
done:
	ticker.Stop()
	return
}

//Init serf Init
func Init(clusterID string, password string, nodeID string, addrs []string, snapshotPath string, c *Config) (*Agent, error) {
	agent, err := InitNode(clusterID, password, nodeID, snapshotPath, c)
	if err != nil {
		logger.Error("InitNode failed, error: %s", err)
		return agent, err
	}

	err = agent.JoinByNodeAddrs(addrs)
	if err != nil {
		logger.Error("JoinByNodeIP failed, error: %s", err)
		return agent, err
	}

	return agent, err
}

//InitNode web后台收到创建集群的请求，
func InitNode(clusterID string, password string, nodeID string, snapshotPath string, c *Config) (*Agent, error) {
	conf := DefaultConfig()
	conf.MergeConf(c)

	logger.Info("clusterID:", clusterID, "password:", password, "nodeID:", nodeID)
	conf.ClusterID = clusterID
	conf.NodeName = nodeID
	if password == "" {
		conf.EncryptKey = DefaultEncryptKey
	} else {
		if len(password) >= 16 {
			password = password[:16]
		} else {
			password = fmt.Sprintf("%016s", password)[:16]
			//return nil, fmt.Errorf("error password")
		}
		conf.EncryptKey = password
	}
	agent, err := Create(conf, snapshotPath)
	if err != nil {
		logger.Error("create agent failed, error: %s", err)
		return agent, err
	}

	agent.Start(conf.Ctx)
	//<- agent.readyCh

	time.Sleep(time.Second)
	logger.Info("Stats:", agent.Agent.Serf().Stats())
	logger.Info("EncryptionEnabled:", agent.Agent.Serf().EncryptionEnabled())
	logger.Info("create agent sucess!!")

	return agent, nil
}

func (a *Agent) JoinByNodeAddrs(addrs []string) error {
	var nodes []string

	if len(addrs) == 0 {
		return fmt.Errorf("No Nodes To Join!")
	}
	for _, addr := range addrs {
		nodes = append(nodes, addr)
	}

	a.Agent.Join(nodes, true)

	return nil
}

//func (a *Agent) JoinByNodeIP(ips []string) error {
//	var nodes []string
//
//	if len(ips) == 0 {
//		return fmt.Errorf("No Nodes To Join!")
//	}
//	for _, ip := range ips {
//		node := fmt.Sprintf("%s:%d", ip, DefaultBindPort)
//		nodes = append(nodes, node)
//	}
//
//	n, err := a.Agent.Join(nodes, true)
//	if err != nil || n == 0 {
//		return fmt.Errorf("Error Encrypt Key!")
//	}
//
//	return err
//}

func (a *Agent) GetNodes() (nodes []NodeInfo) {
	var node NodeInfo
	logger.Info("a.conf.ClusterID:", a.conf.ClusterID)
	mbs := a.GroupMembers(a.conf.ClusterID)
	for _, mb := range mbs {
		node.NodeID = mb.Name
		node.NodeAddress = mb.Addr.String() + ":" + strconv.Itoa(int(mb.Port))
		node.IsAlive = int(mb.Status)
		node.ClusterID = mb.Tags[tagKeyClusterID]

		nodes = append(nodes, node)
	}

	return nodes
}