/*
	Package for parsing devicePrs byte stream to struct.
*/

package parser

import (
	"database/sql"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"net/http"
	"strings"
	"time"

	"bytes"

	"io/ioutil"

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

const (
	statusSent      = 1
	statusDelivered = 2
	statusError     = -1
)

const (
	timeLayout = "2006-01-02 15:04:05"
)

//NACK response, CRC = 565
var rNACK = []byte{0x00, 0x02, 0x64, 0x00, 0x02, 0x35}

//ACK response, CRC = 5052
var rACK = []byte{0x00, 0x02, 0x64, 0x01, 0x13, 0xBC}

//trasparent channel error
var rEmpty = []byte{0x00, 0x02, 0x64, 0x01, 0x13, 0xBC}

//tch empty
var tEmpty = []byte{0, 4, 114, 1, 0, 0, 57, 239}

//PortID for transparent channel
var PortID byte = 0x01

//auto-increment id
var iCounter int64

var sReplacer = strings.NewReplacer("\\", "\\\\", ":", "\\:", "$", "\\$")

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

//DevicePrsOptions store specific parser options
type DevicePrsOptions struct {
	messageAPI     string
	reportAPI      string
	serviceTimeout time.Duration
	appendIMEI     bool
	SetActive      bool
	insertQuery    string
	serviceClient  *http.Client
	tagOption  	   *opt.Options
	BrokerServer   string
	BrokerTopic    string
	DeviceName     string
}

//ISOTime encapsulate timestamp for JSON parsing
type ISOTime struct {
	time.Time
}

//BroadcastMessage store message information to be broadcasted
type BroadcastMessage struct {
	Timestamp ISOTime `json:"ts"`
	Duration  int     `json:"duration"`
	NBuzzer   int     `json:"nbuzzer"`
	Message   string  `json:"message"`
	Expired   ISOTime `json:"expired"`
}

//MessageStatus for specific IMEI
type MessageStatus struct {
	IMEI      string `json:"imei"`
	Status    string `json:"status"`
	Timestamp string `json:"timestamp"`
}

//DevicePrsParser encapsulate parser configuration for DevicePrs device
type DevicePrsParser struct {
	options       *DevicePrsOptions
	db            *sql.DB
	MaxPacketSize int
	MinPacketSize int
	BufferSize    int
	Data          []byte
	IMEI          uint64
	Error         error
	Command       byte
	//Records       *model.DeviceRecords
	Records		  DeviceRecordHeader
	procdr 		  *kafka.Producer
}

//UnmarshalJSON convert string to timestamp
func (tm *ISOTime) UnmarshalJSON(b []byte) (err error) {
	//TODO time other than local
	s := strings.Trim(string(b), "\"")
	tm.Time, err = time.ParseInLocation(timeLayout, s, time.Local)
	if err != nil {
		tm.Time = time.Time{}
	}
	return err
}

//GetMaxPacketSize return maximum packet size for this parser
func (p *DevicePrsParser) GetMaxPacketSize() int {
	return p.MaxPacketSize
}

//GetMinPacketSize return minimum valid packet size for this parser
func (p *DevicePrsParser) GetMinPacketSize() int {
	return p.MinPacketSize
}

//GetBufferSize return buffer size for reading data
func (p *DevicePrsParser) GetBufferSize() int {
	return p.BufferSize
}

//GetError return last error
func (p *DevicePrsParser) GetError() error {
	if p.Error != nil {
		return p.Error
	}
	return nil
}

//Payload return data associated stored in
func (p *DevicePrsParser) Payload() []byte {
	//Field        Packet length   IMEI    Command ID    Payload Data     CRC16
	//Size (bytes) 2               8       1             [1-1009]         2
	n := len(p.Data)
	if n < p.MinPacketSize {
		return []byte{}
	}

	return p.Data[11:(n - 2)]
}

//GetStream return data stream
func (p *DevicePrsParser) GetStream() []byte {
	return p.Data
}

//GetIMEI return IMEI
func (p *DevicePrsParser) GetIMEI() uint64 {
	return p.IMEI
}

//GetCommand return command associated to this packet
func (p *DevicePrsParser) GetCommand() byte {
	return p.Command
}

func (p *DevicePrsParser) saveToDatabase() error {
	imei := fmt.Sprintf("%d", p.IMEI)
	dInHex := hex.EncodeToString(p.Data)

	//TODO, make packet invalid if IMEI is not registered
	db := p.db
	if db != nil {
		//TODO: save data to database
		//`INSERT INTO "GPS_DATA"("IMEI", "DATA_LOG", "FLAG", "DATE_INS", "DESC", "GPS_CODE", "DATA_LEN")
		//VALUES($1, $2, $3, $4, $5, $6, $7)`
		now := time.Now().Local().Format(timeLayout)
		query := p.options.insertQuery
		result, err := db.Exec(query, imei, dInHex, false, now, "", p.options.DeviceName, len(p.Data))
		if err != nil {
			log.Printf("INSERT ERROR: %s -> %s; %s: %s\n", err.Error(), query, imei, dInHex)
			return err
		}
		id, _ := result.LastInsertId()
		nrows, _ := result.RowsAffected()
		log.Printf("IMEI: %v, insert-id: %d, nrows: %d\n", imei, id, nrows)
	} else {
		//if database not defined, display packet in log
		log.Printf("IMEI: %v\n  Data: %v\n", imei, dInHex)
	}

	return nil
}

func (p *DevicePrsParser) sendToBroker() error {
	imei := fmt.Sprintf("%d", p.IMEI)

	//TODO, make packet invalid if IMEI is not registered
	procdr := p.procdr
	if procdr != nil {
		dataJson, err := json.Marshal(p.Records)
	    if err != nil {
	        log.Printf("Error parse to JSON (IMEI: %v): %s\n", imei, err)
	    }
	    //log.Printf("JSON : %v\n",string(dataJson))

	    log.Printf("Number of records: %d (IMEI: %v)\n", p.Records.NumRec, imei)

		//broker
		topic := p.options.BrokerTopic
		//producer channel
		doneChan := make(chan bool)
		go func() {
			defer close(doneChan)
			for e := range procdr.Events() {
				switch ev := e.(type) {
				case *kafka.Message:
					m := ev
					if m.TopicPartition.Error != nil {
						log.Printf("Sent failed: %v (IMEI: %v)\n", m.TopicPartition.Error, imei)
					} else {
						log.Printf("Sent message to topic %s [%d] at offset %v (IMEI: %v)\n",
				*m.TopicPartition.Topic, m.TopicPartition.Partition, m.TopicPartition.Offset, imei)
					}
					return

				default:
					log.Printf("Ignored event: %s (IMEI: %v)\n", ev,imei)
				}
			}
		}()
		value := string(dataJson)
		procdr.ProduceChannel() <- &kafka.Message{
			TopicPartition: kafka.TopicPartition{Topic: &topic, Partition: kafka.PartitionAny}, 
			Value: 			[]byte(value),
			Headers:        []kafka.Header{{Key: imei, Value: []byte(  p.Records.Tstamp.String() )}},
		}
		// wait for delivery report goroutine to finish
		_ = <-doneChan

	} else {
		//if database not defined, display packet in log
		log.Printf("Message Broker not defined, IMEI: %v\n", imei)
	}

	return nil
}

func (p *DevicePrsParser) getJSON(url string, target interface{}) error {
	r, err := p.options.serviceClient.Get(url)
	if err != nil {
		return err
	}
	defer r.Body.Close()

	return json.NewDecoder(r.Body).Decode(target)
}

func (p *DevicePrsParser) putJSON(url string, data interface{}) error {
	if p.options == nil {
		return errors.New("PUT error, options not defined")
	}

	payload, err := json.Marshal(data)
	if err != nil {
		return err
	}
	reader := bytes.NewReader(payload)
	client := p.options.serviceClient
	req, err := http.NewRequest("PUT", url, reader)
	if err != nil {
		return err
	}
	req.ContentLength = int64(len(payload))
	req.Header.Set("Content-Type", "application/json")
	response, err := client.Do(req)
	if err != nil {
		return err
	}
	defer response.Body.Close()

	//read content
	result, err := ioutil.ReadAll(response.Body)
	if err != nil {
		return err
	}
	str := string(result)
	if strings.Contains(str, "no") {
		return errors.New("Failed to update message status: " + str)
	}

	//request code
	code := response.StatusCode
	if code == http.StatusOK || code == http.StatusCreated {
		return nil
	}

	status := response.Status
	return errors.New("PUT error with status = " + status)
}

func (p *DevicePrsParser) askForBroadcastMessage() (string, error) {
	if p.options == nil {
		return "", errors.New("GET error, options not defined")
	}
	//Get message from API
	//TODO: can it handle many connections?
	msg := &BroadcastMessage{}

	//alamat internal
	imei := fmt.Sprintf("%d", p.IMEI)
	url := p.options.messageAPI + imei
	err := p.getJSON(url, msg)
	if err != nil {
		return "", err
	}
	now := time.Now()
	if msg.Expired.Before(now) {
		return "", nil
	}

	//get buzzer count
	nbeep := msg.NBuzzer
	if nbeep <= 0 {
		nbeep = 1
	} else if nbeep > 9 {
		nbeep = 9
	}

	dispSec := msg.Duration
	if dispSec <= 0 {
		dispSec = 1
	} else if dispSec > 999 {
		dispSec = 999
	}

	escapedMsg := sReplacer.Replace(msg.Message)
	pesan := fmt.Sprintf(":t%d%03d%v$", nbeep, dispSec, escapedMsg)

	//log message
	log.Printf("IMEI = %d, message = %v\n", p.IMEI, pesan)

	//go update broadcast status (mark as "sent")
	go p.updateBroadcastStatus(statusSent)

	//return the message
	return pesan, nil
}

//Update broadcast status
func (p *DevicePrsParser) updateBroadcastStatus(status int) error {
	now := time.Now()
	report := &MessageStatus{
		IMEI:      fmt.Sprintf("%d", p.IMEI),
		Timestamp: now.Format(timeLayout),
	}
	switch status {
	case statusError:
		//Do nothing
		log.Printf("IMEI=%d, Message status = Error\n", p.IMEI)
	case statusSent:
		report.Status = "sent"
	case statusDelivered:
		report.Status = "delivered"
	}

	if len(report.Status) > 0 && p.options != nil {
		url := p.options.reportAPI
		if p.options.appendIMEI {
			url += fmt.Sprintf("%d", p.IMEI)
		}
		err := p.putJSON(url, report)
		if err != nil {
			log.Printf("PUT request error: %v\n", err)
			return err
		}

		log.Printf("IMEI=%v, Message status = %v\n", report.IMEI, report.Status)
	}

	return nil
}

//GetBroadcastMessage return message payload tobe broadcased to client
func (p *DevicePrsParser) GetBroadcastMessage() ([]byte, error) {
	pesan, err := p.askForBroadcastMessage()
	n := len(pesan)
	if err != nil {
		return nil, err
	}

	//construct message
	npacket := n + 4
	data := make([]byte, 8+n)
	data[0] = byte(npacket >> 8)
	data[1] = byte(npacket)
	data[2] = 0x72
	data[3] = 0x01 //PORT 'B' (TODO: configurable)
	data[4] = 0x00
	data[5] = 0x00

	//setup Payload
	payload := []byte(pesan)
	ptr := data[6:]
	copy(ptr, payload)

	//calculate CRC
	crc := crc16CCITT(data[2:(n + 6)])
	data[n+6] = byte(crc >> 8)
	data[n+7] = byte(crc)

	return data, nil
}

//GetClientResponse return appropriate response to client according to packet
func (p *DevicePrsParser) GetClientResponse() []byte {
	//Get response to client
	//TODO other response
	switch int(p.Command) {
	case model.CMD_RUP_RECORD:
		if p.IMEI == 0 || p.Error != nil {
			return rNACK
		}
		return rACK
	case model.CMD_RUP_TRCH:
		if p.IMEI == 0 || p.Error != nil {
			return tEmpty
		}

		//parse incoming message
		tch, err := parseTchStream(p.Data, p.MinPacketSize, p.MaxPacketSize)
		if err != nil {
			return tEmpty
		}

		//ceck command type
		payload := string(tch.Data)
		if strings.HasPrefix(payload, "GMn") ||
			strings.HasPrefix(payload, "GMi") ||
			strings.HasPrefix(payload, "GMe") {

			//send message if initial, none or error
			data, err := p.GetBroadcastMessage()
			if err != nil {
				p.Error = err
				return tEmpty
			}

			return data
		} else if strings.HasPrefix(payload, "GMo") {
			//ok, message delivered
			go p.updateBroadcastStatus(statusDelivered)
		}

		//empty transparent channel
		return tEmpty
	}

	//empty
	return rEmpty
}

//GetRecords return parsed records
// func (p *DevicePrsParser) GetRecords() *model.DeviceRecords {
// 	if p.IMEI == 0 || p.Error != nil {
// 		return nil
// 	}

// 	//parse stream if not yet done
// 	if p.Records == nil {
// 		//Stream already verified when creating parser
// 		p.Records, p.Error = parseStream(p.Data, p.MinPacketSize, p.MaxPacketSize, true)
// 		if p.Error != nil {
// 			return nil
// 		}
// 	}

// 	return p.Records
// }

//ExecuteAsync perform task
func (p *DevicePrsParser) ExecuteAsync() bool {
	var status bool
	status = true
	//TODO identify according to command
	cmd := p.GetCommand()
	switch cmd {
	case model.CMD_RUP_RECORD:
		err := p.saveToDatabase()
		if err != nil {
			status = false
			p.Error = err
		}

		err = p.sendToBroker()
	}

	return status
}

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

//NewDevicePrsOptions create options for devicePrs
func NewDevicePrsOptions(options *opt.Options) *DevicePrsOptions {
	svcOpt := options.Get("commToDevice")

	defQuery := `INSERT INTO "GPS_DATA"("IMEI", "DATA_LOG", "FLAG", "DATE_INS", "DESC", "GPS_CODE", "DATA_LEN")
		VALUES($1, $2, $3, $4, $5, $6, $7)`
	insertQuery := svcOpt.GetString("insertQuery", defQuery)
	rupOpt := &DevicePrsOptions{
		messageAPI:     svcOpt.GetString("message", ""),
		reportAPI:      svcOpt.GetString("report", ""),
		serviceTimeout: time.Duration(svcOpt.GetInt("serviceTimeout", 10)) * time.Second,
		appendIMEI:     svcOpt.GetBool("appendIMEI", false),
		SetActive:     	svcOpt.GetBool("setActive", false),
		insertQuery:    insertQuery,
		tagOption:		options.Get("iotag"),
		BrokerServer: 	options.Get("messagebroker").GetString("brokerServer",""), 
		BrokerTopic:    options.Get("messagebroker").GetString("brokerTopic",""),
		DeviceName:     options.Get("server").GetString("device",""), 
	}
	//create client
	rupOpt.serviceClient = &http.Client{Timeout: rupOpt.serviceTimeout}

	return rupOpt
}

//NewDevicePrs create empty parser
func NewDevicePrs() *DevicePrsParser {
	p := &DevicePrsParser{
		MaxPacketSize: 2048,
		MinPacketSize: 14,
		BufferSize:    2048,
	}

	return p
}

//NewDevicePrsParser create new parser. Maximum packet size is 1KB
func NewDevicePrsParser(options *DevicePrsOptions, db *sql.DB, data []byte, procdr *kafka.Producer) *DevicePrsParser {
	//allocate parser with maximum and minimum packet size
	p := NewDevicePrs()
	p.options = options
	p.db = db
	p.procdr = procdr

	//verify stream
	if data != nil {
		p.IMEI, p.Command, p.Records, p.Error = verifyStream(data, p.MinPacketSize, p.MaxPacketSize, options.tagOption)
		if p.Error == nil {
			p.Data = data
		}
	} else {
		p.Error = fmt.Errorf("Stream is empty")
	}
	return p
}

//NewDevicePrsStringParser create new parser which accept HEX string.
//Maximum packet size is 1KB i.e. maximum string length is 2KB
func NewDevicePrsStringParser(options *DevicePrsOptions, db *sql.DB, data string, procdr *kafka.Producer) *DevicePrsParser {
	stream, err := hex.DecodeString(data)
	p := NewDevicePrsParser(options, db, stream,procdr)
	if err != nil {
		p.Error = err
	}
	return p
}

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