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

package parser

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"time"
	//"encoding/hex"
	"strconv"
	"sort"
	"github.com/ipsusila/opt"

	"../model"
)

type ruptelaTchHeader struct {
	Length    uint16
	IMEI      uint64
	CommandID byte
	PortID    byte
	Reserved  uint16
	Timestamp uint32
}

type DeviceRecordHeader struct {
	Imei 			uint64
	Tstamp 			time.Time
	NumRec          uint16
	DeviceRecords	[]DeviceRecord
}

type DeviceRecord struct {
	Tstamp 			time.Time
	TstampInt 		int64
	Imei 			uint64
    Longitude 		float64
	Latitude  		float64
	Altitude  		uint16
	Angle     		uint16
	Satelites 		uint16
	Speed     		uint16
	TagDevices		map[string]TagDevice
}

type TagDevice struct {
	TagName 	string
	TagId 		string
	TagDataType string
	TagVal		string
}

// ByTstamp implements sort.Interface for []DeviceRecord based on
// the TstampInt field.
type ByTstamp []DeviceRecord

func (a ByTstamp) Len() int           { return len(a) }
func (a ByTstamp) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
func (a ByTstamp) Less(i, j int) bool { return a[i].TstampInt < a[j].TstampInt }

/*
	Verify that content of the byte stream match defined format
*/
func verifyStream(data []byte, minSize int, maxSize int, tagOption *opt.Options) (imei uint64, cmd byte, rec DeviceRecordHeader, err error) {
	dlen := len(data)
	if dlen < minSize {
		return 0, 0,rec, fmt.Errorf("Packet size is too small (< %d)", dlen)
	} else if dlen > maxSize {
		return 0, 0,rec, fmt.Errorf("Packet size is greater than maximum allowed size (%d)", dlen)
	}

	//Extract packet size
	sz := int(binary.BigEndian.Uint16(data[:2]))
	if sz != (dlen - 4) {
		return 0, 0,rec, fmt.Errorf("Size field mismatched (!%d)", dlen)
	}

	//extract IMEI
	imei = binary.BigEndian.Uint64(data[2:10])

	//extract and verify CRC
	crc := binary.BigEndian.Uint16(data[dlen-2:])
	ccrc := crc16CCITT(data[2 : dlen-2])
	if crc != ccrc {
		return 0, 0,rec, fmt.Errorf("Invalid Ruptela packet (CRC-16 does not match)")
	}

	//parse data
	rec = parseData(data,imei,tagOption)

	//extract command
	cmd = data[10]

	fmt.Printf("cmd %v\n",cmd)

	return imei, cmd, rec, nil
}

/*
	Parse byte stream and convert to standard record format
*/
func parseData(data []byte, imei uint64, tagOption *opt.Options) (rec DeviceRecordHeader) {
	//allocate records
	rec.Tstamp = time.Now()
	rec.Imei = imei

	tagOption_ := tagOption.GetObjectArray("tags")
  	lengthTags := len(tagOption_)
  	tags := make(map[string]TagDevice)
  	for i:=0; i<lengthTags; i++ {
  		var tag TagDevice
  		tag.TagName = tagOption_[i].GetString("tagName","")
		tag.TagId = tagOption_[i].GetString("tagId","")
		tag.TagDataType = tagOption_[i].GetString("tagDataType","")
		tag.TagVal = ""
  		
  		tags[tag.TagId] = tag
  	}

	//number of records
	currByte := 12
	plusByte := currByte + 1
	numRec := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"numRec")
	//fmt.Printf("Number of records %d\n", numRec) 
	rec.NumRec = numRec
	deviceRecords := make([]DeviceRecord, 0)
	for j := 0; j < int(numRec); j++ {
		var deviceRecord DeviceRecord
		tags_ := tags

		//imei
		deviceRecord.Imei = imei

		//Timestamp
		currByte = plusByte
		plusByte = currByte + 4
		tstampInt := convBinaryToInt32(data[currByte:plusByte],8,"tstampInt")
		tstamp := time.Unix(int64(tstampInt), 0)
	    //fmt.Printf("Timestamp %v\n",tstamp.String())
	    deviceRecord.TstampInt = int64(tstampInt)
	    deviceRecord.Tstamp = tstamp

	    //Priority
	    currByte = plusByte
		plusByte = currByte + 2

		//Longitude
	    currByte = plusByte
		plusByte = currByte + 4
		lonInt := convBinaryToInt32(data[currByte:plusByte],4,"lonInt")
		lon :=float64(lonInt)/10000000
		//fmt.Printf("lon %f\n",lon)
		deviceRecord.Longitude = lon

		//Latitude
	    currByte = plusByte
		plusByte = currByte + 4
		latInt := convBinaryToInt32(data[currByte:plusByte],4,"latInt")
		lat :=float64(latInt)/10000000
		//fmt.Printf("lat %f\n",lat)
		deviceRecord.Latitude = lat

		//Altitude
	    currByte = plusByte
		plusByte = currByte + 2
		alt := convBinaryToUint16(data[currByte:plusByte],2,"alt")
		//fmt.Printf("alt %d\n",alt)
		deviceRecord.Altitude = alt/10
		
		//Angle
	    currByte = plusByte
		plusByte = currByte + 2
		angle := convBinaryToUint16(data[currByte:plusByte],2,"angle")
		//fmt.Printf("angle %d\n",angle)
		deviceRecord.Angle = angle/100
		
		//Satelite
	    currByte = plusByte
		plusByte = currByte + 1
		satelites := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"satelites")
		//fmt.Printf("satelites %d\n",satelites)
		deviceRecord.Satelites = satelites
		
		//Speed
	    currByte = plusByte
		plusByte = currByte + 2
		speed := convBinaryToUint16(data[currByte:plusByte],2,"speed")
		//fmt.Printf("speed %d\n",speed)
		deviceRecord.Speed = speed

		//HDOP - 09 (HEX) 9 (DEC) need to be divided by 10
		currByte = plusByte
		plusByte = currByte + 1

		//IO data cause record - 09 (HEX) 9 (DEC)
		currByte = plusByte
		plusByte = currByte + 1

		//--------------------------------------------------------------------
		//read 1 Byte I/O values
		//--------------------------------------------------------------------
		//Total IO elements, which length is 1 Byte
		currByte = plusByte
		plusByte = currByte + 1
		totalOneByteIO := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"totalOneByteIO")
		//fmt.Printf("total IO1 %d\n",totalOneByteIO)
		for i := 0; i < int(totalOneByteIO); i++ {

			currByte = plusByte
			plusByte = currByte + 1
			ioID := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"io1ID")
			//fmt.Printf("io1ID %d\n",ioID)

			currByte = plusByte
			plusByte = currByte + 1
			ioVal := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"io1Val")
			//fmt.Printf("io1Val %d\n",ioVal)

			tagDevice_ := tags_[strconv.Itoa(int(ioID))]
			tagDevice_.TagId = strconv.Itoa(int(ioID))
			tagDevice_.TagVal = strconv.Itoa(int(ioVal))
			if tagDevice_.TagName != ""{
				//tags_[strconv.Itoa(int(ioID))] = tagDevice_
				tags_[tagDevice_.TagName] = tagDevice_
				delete(tags_, strconv.Itoa(int(ioID)))
			}
			
		}

		//--------------------------------------------------------------------
		//read 2 Byte I/O values
		//--------------------------------------------------------------------
		//Total IO elements, which length is 2 Byte
		currByte = plusByte
		plusByte = currByte + 1
		totalTwoByteIO := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"totalTwoByteIO")
		//fmt.Printf("total IO2 %d\n",totalTwoByteIO)
		for i := 0; i < int(totalTwoByteIO); i++ {

			currByte = plusByte
			plusByte = currByte + 1
			ioID := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"io2ID")
			//fmt.Printf("io2ID %d\n",ioID)

			currByte = plusByte
			plusByte = currByte + 2
			ioVal := convBinaryToUint16(data[currByte:plusByte],2,"io2Val")
			//fmt.Printf("io2Val %d\n",ioVal)

			tagDevice_ := tags_[strconv.Itoa(int(ioID))]
			tagDevice_.TagVal = strconv.Itoa(int(ioVal))
			if tagDevice_.TagName != ""{
				tags_[tagDevice_.TagName] = tagDevice_
			}
		}

		//--------------------------------------------------------------------
		//read 4 Byte I/O values
		//--------------------------------------------------------------------
		//Total IO elements, which length is 4 Byte
		currByte = plusByte
		plusByte = currByte + 1
		totalFourByteIO := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"totalFourByteIO")
		//fmt.Printf("total IO4 %d\n",totalFourByteIO)
		for i := 0; i < int(totalFourByteIO); i++ {

			currByte = plusByte
			plusByte = currByte + 1
			ioID := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"io4ID")
			//fmt.Printf("io4ID %d\n",ioID)

			currByte = plusByte
			plusByte = currByte + 4
			ioVal := convBinaryToInt32(data[currByte:plusByte],4,"io4Val")
			//fmt.Printf("io4Val %d\n",ioVal)

			tagDevice_ := tags_[strconv.Itoa(int(ioID))]
			tagDevice_.TagVal = strconv.FormatInt(int64(ioVal), 10)
			if tagDevice_.TagName != ""{
				tags_[tagDevice_.TagName] = tagDevice_
			}
		}

		//--------------------------------------------------------------------
		//read 8 Byte I/O values
		//--------------------------------------------------------------------
		//Total IO elements, which length is 8 Byte
		currByte = plusByte
		plusByte = currByte + 1
		total8ByteIO := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"total8ByteIO")
		//fmt.Printf("total IO8 %d\n",total8ByteIO)
		for i := 0; i < int(total8ByteIO); i++ {

			currByte = plusByte
			plusByte = currByte + 1
			ioID := convBinaryToUint16(addOneByteInTwoByte(data[currByte:plusByte]),2,"io8ID")
			//fmt.Printf("io8ID %d\n",ioID)

			currByte = plusByte
			plusByte = currByte + 8
			ioVal := convBinaryToInt64(data[currByte:plusByte],8,"io8Val")
			//fmt.Printf("io8Val %d\n",ioVal)

			tagDevice_ := tags_[strconv.Itoa(int(ioID))]
			tagDevice_.TagVal = strconv.FormatInt(int64(ioVal), 10)
			if tagDevice_.TagName != ""{
				tags_[tagDevice_.TagName] = tagDevice_
			}
		}

		//Delete unset tags value
		for tagKey := range tags {
			tagDevice_ := tags_[tagKey]
			if tagDevice_.TagId == tagKey {
				delete(tags_, tagKey)
			}
	  	}

		deviceRecord.TagDevices = tags_
		deviceRecords = append(deviceRecords, deviceRecord)

	}

	//sort ascending by date
	sort.Sort(ByTstamp(deviceRecords))

	rec.DeviceRecords = deviceRecords

	//CRC-16
	currByte = plusByte
	plusByte = currByte + 2

	return rec

}

/*
	Convert Binary to uint16
*/
func addOneByteInTwoByte(data []byte) (resultData []byte){

	dataNew := make([]byte, 2)
	dataNew[0] = 0x0
	copy(dataNew[1:], data)

	return dataNew
}

/*
	Convert Binary to uint16
*/
func convBinaryToUint16(data []byte, byteLength int, desc string) (reslt uint16){
	var dataInt uint16
	dataNew := make([]byte, byteLength)
	copy(dataNew[0:], data)
	buf1 := bytes.NewReader(dataNew)
	err := binary.Read(buf1, binary.BigEndian, &dataInt)
	if err != nil {
		fmt.Printf("binary.Read failed %v :%v\n", desc, err)
		dataInt = 0
	}
	return dataInt
}

/*
	Convert Binary to int32
*/
func convBinaryToInt32(data []byte, byteLength int, desc string) (reslt int32){
	var dataInt int32
	dataNew := make([]byte, byteLength)
	copy(dataNew[0:], data)
	buf1 := bytes.NewReader(dataNew)
	err := binary.Read(buf1, binary.BigEndian, &dataInt)
	if err != nil {
		fmt.Printf("binary.Read failed %v :%v\n", desc, err)
		dataInt = 0
	}
	return dataInt
}

/*
	Convert Binary to int64
*/
func convBinaryToInt64(data []byte, byteLength int, desc string) (reslt int64){
	var dataInt int64
	dataNew := make([]byte, byteLength)
	copy(dataNew[0:], data)
	buf1 := bytes.NewReader(dataNew)
	err := binary.Read(buf1, binary.BigEndian, &dataInt)
	if err != nil {
		fmt.Printf("binary.Read failed %v :%v\n", desc, err)
		dataInt = 0
	}
	return dataInt
}

func parseTchStream(data []byte, minSize int, maxSize int) (*model.DisplayRequest, error) {
	rec := &model.DisplayRequest{}

	//check length
	dataLen := len(data)
	if dataLen < minSize {
		return rec, fmt.Errorf("Packet size is too small (< %d)", dataLen)
	}
	if dataLen > maxSize {
		return rec, fmt.Errorf("Packet size is greater than maximum allowed size (%d)", dataLen)
	}

	//create buffer
	buf := bytes.NewBuffer(data)

	//read packet header part
	pktHdr := &ruptelaTchHeader{}
	err := binary.Read(buf, binary.BigEndian, pktHdr)
	if err != nil {
		return rec, fmt.Errorf("Failed to read packet header (%v)", err)
	}
	//2+8+1+1+2+4 (len, imei, cmd, port, reserved, timestamp)
	idx := 2 + 8 + 1 + 1 + 2 + 4

	rec.IMEI = pktHdr.IMEI
	rec.PortID = pktHdr.PortID
	rec.Timestamp = time.Unix(int64(pktHdr.Timestamp), 0)
	rec.Data = data[idx:(dataLen - 2)]

	return rec, nil
}

// Calculate CRC16 with CCITT algorithm
// Based on C/C++ code in DevicePrs protocol documents
// CRC calculation omits Length(2-bytes) and CRC itself (2-bytes)
func crc16CCITT(data []byte) uint16 {
	//--------------------------------------------------------------------
	var ucBit, ucCarry uint16
	//--------------------------------------------------------------------
	var usPoly uint16 = 0x8408 //reversed 0x1021
	var usCRC uint16           //initialized as zero
	//--------------------------------------------------------------------
	for _, d := range data {
		usCRC ^= uint16(d)
		for ucBit = 0; ucBit < 8; ucBit++ {
			ucCarry = usCRC & 1
			usCRC >>= 1
			if ucCarry != 0 {
				usCRC ^= usPoly
			}
		}
	}
	//--------------------------------------------------------------------
	return usCRC
	//--------------------------------------------------------------------
}