/*
 * 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"
	"io/ioutil"
	"net"
	"os"

	//"os"
	"strings"
	"time"

	"github.com/hashicorp/serf/cmd/serf/command/agent"
	"github.com/hashicorp/serf/serf"
	//"github.com/apache/servicecomb-service-center/pkg/log"
	"log"
)

const (
	QueryEventGetDB        = "GetDatabase"
	QueryEventUpdateDBData = "UpdateDBData"
)

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

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) (*Agent, error) {
	// config cover to serf config
	serfConf, err := conf.convertToSerf()
	if err != nil {
		return nil, err
	}

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

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

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

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

// 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) {

	switch ev := event.(type) {
	case serf.UserEvent:
		var sqlUe SqlUserEvent
		fmt.Println(string(ev.Payload))
		err := json.Unmarshal(ev.Payload, &sqlUe)
		if err !=nil {
			fmt.Println("sqlUe unmarshal err:",err)
			return
		}
		if sqlUe.Owner != a.conf.NodeName {
			results, _ := ExecuteWriteSql(sqlUe.Sql)
			//flag, _ := ExecuteSqlByGorm(sqlUe.Sql)
			fmt.Println("userEvent exec ",sqlUe.Sql,",Result:",results)
		}

	case *serf.Query:

		if ev.Name == QueryEventGetDB {
			//bak file and send resp
			filename, err := BakDbFile()
			if err != nil {
				fmt.Println("bak db file error!")
				return
			}
			fmt.Println(filename)

			filebuf, err := ioutil.ReadFile(filename)
			fmt.Println("filebuf: ", len(filebuf))
			if err != nil {
				fmt.Printf("file to []bytes error: %s\n", err)
				return
			}

			err = os.Remove(filename)
			if err != nil {
				fmt.Printf("remove file%s\n failed", filename)
				return
			}

			fmt.Println("query payload: ", len(ev.Payload))
			if query, ok := event.(*serf.Query); ok {
				if err := query.Respond(filebuf); err != nil {
					fmt.Printf("err: %s\n", err)
					return
				}
			}
		} else if ev.Name == QueryEventUpdateDBData {
			fmt.Println(string(ev.Payload))
			var tmpstringslice []string
			tmpstringslice = append(tmpstringslice, string(ev.Payload))
			fmt.Println(tmpstringslice)
			rows, err := ExecuteQuerySql(tmpstringslice)
			if err != nil {
				fmt.Println("err: ", err)
				return
			}
			var rowsReturn []Rows
			for _, r := range rows {
				rowsReturn = append(rowsReturn, *r)
			}

			bytesReturn, err := json.Marshal(rowsReturn)
			fmt.Println("results: ", bytesReturn)
			if query, ok := event.(*serf.Query); ok {
				if err := query.Respond(bytesReturn); err != nil {
					fmt.Printf("err: %s\n", err)
					return
				}
			}

			//var res []*Rows
			//json.Unmarshal(bytesReturn, &res)
		}
		case serf.MemberEvent:
			if event.EventType() == serf.EventMemberLeave {
				if ev.Members !=nil && len(ev.Members) ==1 {
					leaveMember := ev.Members[0]
					leaveSql := "delete from cluster_node where node_id='"+leaveMember.Name+"'"
					fmt.Println("leaveSql:",leaveSql)
					//ExecuteSqlByGorm([]string{ leaveSql })

					fmt.Println("EventMemberLeave,current Members:",ev.Members)
				}
				return
			}


	default:
		fmt.Printf("Unknown event type: %s\n", ev.EventType().String())
	}

	//if event.EventType() != serf.EventMemberJoin {
	//	fmt.Printf("event.EventType() != serf.EventMemberJoin")
	//	return
	//}
	//
	//if a.conf.Mode == ModeCluster {
	//	if len(a.GroupMembers(a.conf.ClusterID)) < groupExpect {
	//		fmt.Printf("len(a.GroupMembers(a.conf.ClusterID)) < groupExpect")
	//		return
	//	}
	//}
	//a.DeregisterEventHandler(a)
	//close(a.readyCh)
}

func (a *Agent) BroadcastMemberlist(delay time.Duration) {
	//serf := a.serf
	serf := a.Agent.Serf()
	mb := serf.LocalMember()
	mblist := serf.Memberlist()
	fmt.Println("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 {
		// fmt.Printf("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 {
		a.Leave()
		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() {
			log.Printf("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 {
		log.Printf("retry join mumber %d", len(a.conf.RetryJoin))
		return nil
	}

	// Count of attempts
	attempt := 0
	ticker := time.NewTicker(a.conf.RetryInterval)
	for {
		log.Printf("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 {
			log.Printf("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")
			log.Println(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
}

//GetDbFromCluster get the newest database after join cluster
//dbPathWrite the path where to write after got a database,
func (a *Agent) GetDbFromCluster(dbPathWrite string) {
	//members: get name of first member
	mbs := a.GroupMembers(a.conf.ClusterID)
	var specmembername string
	for _, m := range mbs {
		if m.Addr.String() != a.conf.BindAddr {
			specmembername = m.Name
			break
		}
	}
	fmt.Println(specmembername)

	//query: get db file.
	params := serf.QueryParam{
		FilterNodes: strings.Fields(specmembername),
	}

	resp, err := a.Query(QueryEventGetDB, []byte(""), &params)
	if err == nil || !strings.Contains(err.Error(), "cannot contain") {
		fmt.Println("err: ", err)
	}

	go func() {
		respCh := resp.ResponseCh()
		for {
			select {
			case r := <-respCh:
				fmt.Println("x length is: ", len(r.Payload))

				// // byte to file.
				SerfDbConn.Close()
				SerfDbConn = nil
				err = ioutil.WriteFile(dbPathWrite, r.Payload, 0644)
				if err != nil {
					fmt.Println("query byte to file error!", err)
				}
				err := InitDbConn("")
				if err != nil {
					fmt.Println("create db conn of test.db error: ", err)
				}
				return
			}
		}
	}()
}

type SqlUserEvent struct {
	Owner string `json:"owner"`
	Sql []string `json:"sql"`
}
//SyncSql boardcast sql to cluster
func (a *Agent) SyncSql(sqlOp []string) {
	// event : use to send command to operate db.
	var sqlUe = SqlUserEvent{
		Owner: a.conf.NodeName,
		Sql: sqlOp,
	}
	ueB, err := json.Marshal(sqlUe)
	if err !=nil {
		fmt.Println("sqlUE marshal err:",err)
		return
	}
	err = a.UserEvent("SyncSql", []byte(ueB), false)
	if err == nil || !strings.Contains(err.Error(), "cannot contain") {
		fmt.Println("err: ", err)
	}
}

//Init serf Init
func Init(clusterID string, password string, nodeID string, ips []string) (*Agent, error) {
	agent, err := InitNode(clusterID, password, nodeID)
	if err != nil {
		fmt.Printf("InitNode failed, error: %s", err)
		return agent, err
	}

	err = agent.JoinByNodeIP(ips)
	if err != nil {
		fmt.Printf("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) (*Agent, error) {
	conf := DefaultConfig()
	fmt.Println("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)
	if err != nil {
		fmt.Printf("create agent failed, error: %s", err)
		return agent, err
	}

	agent.Start(context.Background())
	//<- agent.readyCh
	go func() {
		agent.ShutdownCh()
	}()
	time.Sleep(time.Second)
	fmt.Println("Stats:", agent.Agent.Serf().Stats())
	fmt.Println("EncryptionEnabled:", agent.Agent.Serf().EncryptionEnabled())
	fmt.Println("create agent sucess!!")

	return agent, 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 {
		//a.Stop()
		//fmt.Println("Stop node")
		return fmt.Errorf("Error Encrypt Key!")
	}

	return err
}

type Node struct {
	clusterID string
	NodeID    string
	IP        string
	isAlive   int //StatusNone:0, StatusAlive:1, StatusLeaving:2, StatusLeft:3, StatusFailed:4
}

func (a *Agent) GetNodes() (nodes []Node) {
	var node Node
	fmt.Println("a.conf.ClusterID:", a.conf.ClusterID)
	mbs := a.GroupMembers(a.conf.ClusterID)
	for _, mb := range mbs {
		node.NodeID = mb.Name
		node.IP = mb.Addr.String()
		node.isAlive = int(mb.Status)
		node.clusterID = mb.Tags[tagKeyClusterID]

		nodes = append(nodes, node)
	}

	return nodes
}