//
//  DevicePrs Devie Server based on Go net package
//  specify Mode=net in model.ServerConfig
//

package server

import (
	"database/sql"
	"encoding/binary"
	"errors"
	"io"
	"log"
	"net"
	"os"
	"os/signal"
	"syscall"
	"time"
	"encoding/hex"
	"sync"
	"math"

	"github.com/gansidui/gotcp"
	"github.com/ipsusila/opt"
	"github.com/confluentinc/confluent-kafka-go/kafka"
	//"../model"
	"../parser"
)

//-------------------------------------------------------------------

var serverId = ""

type ConnectionDevice struct {
	imei 		uint64
	data 		[]byte
	timeProcess time.Time
}
type MapConnection struct {
	addr map[string]ConnectionDevice
	mux  sync.Mutex
}
func (c *MapConnection) AddUpdt(key string,connectionDevice ConnectionDevice) {
	c.mux.Lock()
	// Lock so only one goroutine at a time can access the map c.v.
	c.addr[key] = connectionDevice
	c.mux.Unlock()
}
func (c *MapConnection) Del(key string) {
	c.mux.Lock()
	// Lock so only one goroutine at a time can access the map c.v.
	delete(c.addr, key)
	c.mux.Unlock()
}
func (c *MapConnection) Value(key string) ConnectionDevice {
	c.mux.Lock()
	// Lock so only one goroutine at a time can access the map c.v.
	defer c.mux.Unlock()
	return c.addr[key]
}
var connectionDevices = MapConnection{addr: make(map[string]ConnectionDevice)}

//DevicePrsServerPacket holds packet information
type DevicePrsServerPacket struct {
	buff []byte
}

//NewDevicePrsServerPacket create new packet
func NewDevicePrsServerPacket(data []byte) *DevicePrsServerPacket {
	pkt := new(DevicePrsServerPacket)
	pkt.buff = data

	return pkt
}

//Serialize packet
func (p *DevicePrsServerPacket) Serialize() []byte {
	return p.buff
}

//-------------------------------------------------------------------

//DevicePrsServerNet info
type DevicePrsServerNet struct {
	Options  *opt.Options
	Server   *gotcp.Server
	Callback *DevicePrsServerCallback
}

//Stop tcp server
func (rup *DevicePrsServerNet) Stop() {
	rup.Server.Stop()
}

//Start the server
func (rup *DevicePrsServerNet) Start() {
	//---- options ---------------------------------------
	serverOpt := rup.Options.Get("server")
	maxSend := uint32(serverOpt.GetInt("maxSend", 40))
	maxReceive := uint32(serverOpt.GetInt("maxReceive", 40))
	addr := serverOpt.GetString("listenAddr", ":8081")
	acceptTimeout := time.Duration(serverOpt.GetInt("acceptTimeout", 2)) * time.Second
	writeTimeout := time.Duration(serverOpt.GetInt("writeTimeout", 5)) * time.Second

	//database options
	gpsData := rup.Options.Get("gpsdata")
	storage := gpsData.GetString("storage", "sql")

	dbOpt := gpsData.Get(storage)
	dbDriver := dbOpt.GetString("driver", "postgres")
	dbInfo := dbOpt.GetString("connection", "")
	dbMaxIdle := dbOpt.GetInt("maxIdle", 0)
	dbMaxOpen := dbOpt.GetInt("maxOpen", 5)
	dbMaxLifetime := time.Duration(dbOpt.GetInt("maxLifetime", 60)) * time.Second

	//devicePrs options
	rupOpt := parser.NewDevicePrsOptions(rup.Options)

	//server ID
	serverId = serverOpt.GetString("id", "undefined (check configuration)")

	//listen to TCP
	tcpAddr, err := net.ResolveTCPAddr("tcp4", addr)
	if err != nil {
		log.Printf("Error resolving address %v\n", addr)
		return
	}
	listener, err := net.ListenTCP("tcp", tcpAddr)
	if err != nil {
		log.Printf("Error listening to tcp address %v\n", tcpAddr)
		return
	}

	//open database connection
	db, err := sql.Open(dbDriver, dbInfo)
	if err != nil {
		log.Printf("Error opening db %v\n", dbDriver)
		return
	}
	defer db.Close()

	err = db.Ping()
	if err != nil {
		log.Printf("DB connection error: %v\n", err)
		return
	}
	db.SetMaxIdleConns(dbMaxIdle)
	db.SetMaxOpenConns(dbMaxOpen)
	db.SetConnMaxLifetime(dbMaxLifetime)

	//create procedure broker
	broker := rupOpt.BrokerServer
	procdr, err := kafka.NewProducer(&kafka.ConfigMap{"bootstrap.servers": broker})
	if err != nil {
		log.Printf("Failed to create producer: %s\n", err)
		os.Exit(1)
	}
	log.Printf("Created Producer %v\n", procdr)

	// creates a server
	config := &gotcp.Config{
		PacketSendChanLimit:    maxSend,
		PacketReceiveChanLimit: maxReceive,
	}
	proto := &DevicePrsServerProtocol{
		maxPacketSize: parser.NewDevicePrs().MaxPacketSize,
	}

	//map for storing various statistics
	callback := &DevicePrsServerCallback{
		options:      rupOpt,
		gpsDb:        db,
		writeTimeout: writeTimeout,
		procdr:       procdr,
	}

	srv := gotcp.NewServer(config, callback, proto)
	rup.Server = srv
	rup.Callback = callback

	// starts service
	go srv.Start(listener, acceptTimeout)
	log.Printf("listening: %v\n", listener.Addr())

	// catchs system signal
	chSig := make(chan os.Signal)
	signal.Notify(chSig, syscall.SIGINT, syscall.SIGTERM)
	ch := <-chSig
	log.Printf("Signal: %v\n", ch)

	// stops service
	srv.Stop()
}

//-------------------------------------------------------------------

//DevicePrsServerCallback holds server callback info
type DevicePrsServerCallback struct {
	options      *parser.DevicePrsOptions
	gpsDb        *sql.DB
	writeTimeout time.Duration
	procdr 		 *kafka.Producer
}

//OnConnect is called when new connection established
func (cb *DevicePrsServerCallback) OnConnect(c *gotcp.Conn) bool {
	addr := c.GetRawConn().RemoteAddr()
	c.PutExtraData(addr)
	log.Printf("%v New connection(client: %v)\n", serverId,addr)

	//insert to array new address
	var connDevice ConnectionDevice
	connDevice.imei = 0
	connDevice.timeProcess = time.Now()
	connectionDevices.AddUpdt(addr.String(),connDevice)

	return true
}

//OnMessage is called when packet readed
func (cb *DevicePrsServerCallback) OnMessage(c *gotcp.Conn, p gotcp.Packet) bool {
	addr := c.GetRawConn().RemoteAddr()

	//downcast packet to devicePrs packet
	packet := p.(*DevicePrsServerPacket)
	data := packet.Serialize()
	//fmt.Println(hex.EncodeToString(data))

	//imei is empty so, we have to add last imei to the data
	connectionDevice := connectionDevices.Value(addr.String())

	//create parser
	par := parser.NewDevicePrsParser(cb.options, cb.gpsDb, data, cb.procdr)
	if err := par.GetError(); err != nil {
		log.Printf("Error verifying packet(client: %v): %v, Err=%v\n",
			addr,hex.EncodeToString(data), err)
	}

	//set imei in array imei
	imei_ := connectionDevice.imei
	if(imei_ == 0){
		imei_ = par.IMEI
		connectionDevice.imei = par.IMEI
		connectionDevice.data = data
		connectionDevices.AddUpdt(addr.String(),connectionDevice)
	}
	
	duration := time.Since(connectionDevice.timeProcess)
	log.Printf("Data received(client: %v, IMEI: %v) with duration %v s\n", addr, imei_,math.Round(duration.Seconds()*100)/100)

	//save to database
	statusInsert := par.ExecuteAsync()

	if(statusInsert){
		// send response to client (ACK or NACK)
		rep := par.GetClientResponse()
		c.AsyncWritePacket(NewDevicePrsServerPacket(rep), cb.writeTimeout)
		log.Printf("Sent ACK (client: %v, IMEI: %v)\n", addr, imei_)
	}
	
	//send message if record command
	//if par.GetCommand() == model.CMD_RUP_RECORD {
	//	msg, err := par.GetBroadcastMessage()
	//	if len(msg) > 0 {
	//		c.AsyncWritePacket(NewRuptelaServerPacket(msg), cb.writeTimeout)
	//	} else if err != nil {
	//		log.Printf("Get message error(client: %v, IMEI: %v) = %v\n", addr, par.IMEI,err)
	//	}
	//}

	//run parallel processing to handle packet parsing
	//go par.ExecuteAsync()
	return true
}

//OnClose is called when connection being closed
func (cb *DevicePrsServerCallback) OnClose(c *gotcp.Conn) {
	addr := c.GetRawConn().RemoteAddr()
	connectionDevice := connectionDevices.Value(addr.String())
    duration := time.Since(connectionDevice.timeProcess)
	
	connectionDevices.Del(addr.String())
	log.Printf("%v Close connection (client: %v, IMEI: %v) with duration %v s\n", serverId ,c.GetExtraData(),connectionDevice.imei,math.Round(duration.Seconds()*100)/100)
}

//-------------------------------------------------------------------

//DevicePrsServerProtocol holds parser
type DevicePrsServerProtocol struct {
	maxPacketSize int
}

//ReadPacket called everytime data is available
func (p *DevicePrsServerProtocol) ReadPacket(conn *net.TCPConn) (gotcp.Packet, error) {
	var (
		lengthBytes = make([]byte, 2)
		length      uint16
	)

	//TODO handle packet other than Device Record
	//OK

	// read length
	if _, err := io.ReadFull(conn, lengthBytes); err != nil {
		return nil, err
	}
	Limit := uint16(p.maxPacketSize)
	if length = binary.BigEndian.Uint16(lengthBytes); length > Limit {
		return nil, errors.New("The size of packet is larger than the limit")
	}

	log.Printf("data packet length(client: %v) : %d", conn.RemoteAddr(), length)

	//Packet structure
	//LEN + DATA + CRC16
	buff := make([]byte, 2+length+2)
	copy(buff[0:2], lengthBytes)

	// read body ( buff = lengthBytes + body )
	if _, err := io.ReadFull(conn, buff[2:]); err != nil {
		return nil, err
	}

	return NewDevicePrsServerPacket(buff), nil
}