/*
 * Copyright 2018-present Open Networking Foundation

 * Licensed 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 omci

import (
	"encoding/hex"
	"errors"
	"strconv"

	"github.com/google/gopacket"
	"github.com/opencord/omci-lib-go/v2"
	me "github.com/opencord/omci-lib-go/v2/generated"
	log "github.com/sirupsen/logrus"
)

const (
	cOmciDownloadSectionSizeBaseLine = 31   //in bytes
	cOmciDownloadSectionSizeExtLine  = 1965 //in bytes
)

func ParseStartSoftwareDownloadRequest(omciPkt gopacket.Packet) (*omci.StartSoftwareDownloadRequest, error) {
	msgLayer := omciPkt.Layer(omci.LayerTypeStartSoftwareDownloadRequest)
	if msgLayer == nil {
		err := "omci Msg layer could not be detected for LayerTypeStartSoftwareDownloadRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	msgObj, msgOk := msgLayer.(*omci.StartSoftwareDownloadRequest)
	if !msgOk {
		err := "omci Msg layer could not be assigned for LayerTypeStartSoftwareDownloadRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	return msgObj, nil
}

func ParseDownloadSectionRequest(omciPkt gopacket.Packet) (*omci.DownloadSectionRequest, error) {
	msgLayer := omciPkt.Layer(omci.LayerTypeDownloadSectionRequest)
	if msgLayer == nil {
		err := "omci Msg layer could not be detected for LayerTypeDownloadSectionRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	msgObj, msgOk := msgLayer.(*omci.DownloadSectionRequest)
	if !msgOk {
		err := "omci Msg layer could not be assigned for LayerTypeDownloadSectionRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	return msgObj, nil
}

func ParseEndSoftwareDownloadRequest(omciPkt gopacket.Packet) (*omci.EndSoftwareDownloadRequest, error) {
	msgLayer := omciPkt.Layer(omci.LayerTypeEndSoftwareDownloadRequest)
	if msgLayer == nil {
		err := "omci Msg layer could not be detected for LayerTypeEndSoftwareDownloadRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	msgObj, msgOk := msgLayer.(*omci.EndSoftwareDownloadRequest)
	if !msgOk {
		err := "omci Msg layer could not be assigned for LayerTypeEndSoftwareDownloadRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	return msgObj, nil
}

func ParseActivateSoftwareRequest(omciPkt gopacket.Packet) (*omci.ActivateSoftwareRequest, error) {
	msgLayer := omciPkt.Layer(omci.LayerTypeActivateSoftwareRequest)
	if msgLayer == nil {
		err := "omci Msg layer could not be detected for LayerTypeActivateSoftwareRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	msgObj, msgOk := msgLayer.(*omci.ActivateSoftwareRequest)
	if !msgOk {
		err := "omci Msg layer could not be assigned for LayerTypeActivateSoftwareRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	return msgObj, nil
}

func ParseCommitSoftwareRequest(omciPkt gopacket.Packet) (*omci.CommitSoftwareRequest, error) {
	msgLayer := omciPkt.Layer(omci.LayerTypeCommitSoftwareRequest)
	if msgLayer == nil {
		err := "omci Msg layer could not be detected for LayerTypeCommitSoftwareRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	msgObj, msgOk := msgLayer.(*omci.CommitSoftwareRequest)
	if !msgOk {
		err := "omci Msg layer could not be assigned for LayerTypeCommitSoftwareRequest"
		omciLogger.Error(err)
		return nil, errors.New(err)
	}
	return msgObj, nil
}

func CreateStartSoftwareDownloadResponse(omciPkt gopacket.Packet, omciMsg *omci.OMCI) ([]byte, error) {

	responeCode := me.Success
	msgObj, err := ParseStartSoftwareDownloadRequest(omciPkt)
	if err != nil {
		responeCode = me.ProcessingError
	}
	isExtended := false
	if omciMsg.DeviceIdentifier == omci.ExtendedIdent {
		isExtended = true
	}
	omciLogger.WithFields(log.Fields{
		"OmciMsgType":          omciMsg.MessageType,
		"TransCorrId":          omciMsg.TransactionID,
		"DeviceIdentifier":     omciMsg.DeviceIdentifier,
		"EntityInstance":       msgObj.EntityInstance,
		"WindowSize":           msgObj.WindowSize,
		"ImageSize":            msgObj.ImageSize,
		"NumberOfCircuitPacks": msgObj.NumberOfCircuitPacks,
		"CircuitPacks":         msgObj.CircuitPacks,
	}).Debug("received-start-software-download-request")

	response := &omci.StartSoftwareDownloadResponse{
		MeBasePacket: omci.MeBasePacket{
			EntityClass:    msgObj.EntityClass,
			EntityInstance: msgObj.EntityInstance,
			Extended:       isExtended,
		},
		WindowSize:        msgObj.WindowSize,
		Result:            responeCode,
		NumberOfInstances: 0,                        // NOTE this can't be bigger than 0 this we can populate downloadResults
		MeResults:         []omci.DownloadResults{}, // FIXME downloadResults is not exported
	}
	omciLayer := &omci.OMCI{
		TransactionID:    omciMsg.TransactionID,
		MessageType:      omci.StartSoftwareDownloadResponseType,
		DeviceIdentifier: omciMsg.DeviceIdentifier,
	}
	var options gopacket.SerializeOptions
	options.FixLengths = true

	buffer := gopacket.NewSerializeBuffer()
	err = gopacket.SerializeLayers(buffer, options, omciLayer, response)
	if err != nil {
		omciLogger.WithFields(log.Fields{
			"Err":  err,
			"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		}).Error("cannot-Serialize-StartSoftwareDownloadResponse")
		return nil, err
	}
	pkt := buffer.Bytes()

	log.WithFields(log.Fields{
		"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		"pkt":  hex.EncodeToString(pkt),
	}).Trace("omci-start-software-download-response")

	return pkt, nil
}

func CreateDownloadSectionResponse(omciPkt gopacket.Packet, omciMsg *omci.OMCI) ([]byte, error) {

	msgObj, err := ParseDownloadSectionRequest(omciPkt)

	if err != nil {
		return nil, err
	}
	isExtended := false
	if omciMsg.DeviceIdentifier == omci.ExtendedIdent {
		isExtended = true
	}
	omciLogger.WithFields(log.Fields{
		"OmciMsgType":      omciMsg.MessageType,
		"TransCorrId":      omciMsg.TransactionID,
		"DeviceIdentifier": omciMsg.DeviceIdentifier,
		"EntityInstance":   msgObj.EntityInstance,
		"SectionNumber":    msgObj.SectionNumber,
	}).Debug("received-download-section-request")

	response := &omci.DownloadSectionResponse{
		MeBasePacket: omci.MeBasePacket{
			EntityClass:    msgObj.EntityClass,
			EntityInstance: msgObj.EntityInstance,
			Extended:       isExtended,
		},
		Result:        me.Success,
		SectionNumber: msgObj.SectionNumber,
	}
	omciLayer := &omci.OMCI{
		TransactionID:    omciMsg.TransactionID,
		MessageType:      omci.DownloadSectionResponseType,
		DeviceIdentifier: omciMsg.DeviceIdentifier,
	}
	var options gopacket.SerializeOptions
	options.FixLengths = true

	buffer := gopacket.NewSerializeBuffer()
	err = gopacket.SerializeLayers(buffer, options, omciLayer, response)
	if err != nil {
		omciLogger.WithFields(log.Fields{
			"Err":  err,
			"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		}).Error("cannot-Serialize-DownloadSectionResponse")
		return nil, err
	}
	pkt := buffer.Bytes()

	log.WithFields(log.Fields{
		"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		"pkt":  hex.EncodeToString(pkt),
	}).Trace("omci-download-section-with-response-response")

	return pkt, nil
}

func CreateEndSoftwareDownloadResponse(omciPkt gopacket.Packet, omciMsg *omci.OMCI, status me.Results) ([]byte, error) {

	msgObj, err := ParseEndSoftwareDownloadRequest(omciPkt)

	if err != nil {
		return nil, err
	}
	isExtended := false
	if omciMsg.DeviceIdentifier == omci.ExtendedIdent {
		isExtended = true
	}
	omciLogger.WithFields(log.Fields{
		"OmciMsgType":       omciMsg.MessageType,
		"TransCorrId":       omciMsg.TransactionID,
		"DeviceIdentifier":  omciMsg.DeviceIdentifier,
		"EntityInstance":    msgObj.EntityInstance,
		"Crc32":             msgObj.CRC32,
		"ImageSize":         msgObj.ImageSize,
		"NumberOfInstances": msgObj.NumberOfInstances,
		"ImageInstances":    msgObj.ImageInstances,
	}).Debug("received-end-software-download-request")

	response := &omci.EndSoftwareDownloadResponse{
		MeBasePacket: omci.MeBasePacket{
			EntityClass:    msgObj.EntityClass,
			EntityInstance: msgObj.EntityInstance,
			Extended:       isExtended,
		},
		Result:            status,
		NumberOfInstances: 0, // NOTE this can't be bigger than 0 this we can populate downloadResults
		//MeResults: []omci.downloadResults{}, // FIXME downloadResults is not exported
	}
	omciLayer := &omci.OMCI{
		TransactionID:    omciMsg.TransactionID,
		MessageType:      omci.EndSoftwareDownloadResponseType,
		DeviceIdentifier: omciMsg.DeviceIdentifier,
	}
	var options gopacket.SerializeOptions
	options.FixLengths = true

	buffer := gopacket.NewSerializeBuffer()
	err = gopacket.SerializeLayers(buffer, options, omciLayer, response)
	if err != nil {
		omciLogger.WithFields(log.Fields{
			"Err":  err,
			"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		}).Error("cannot-Serialize-EndSoftwareDownloadResponse")
		return nil, err
	}
	pkt := buffer.Bytes()

	log.WithFields(log.Fields{
		"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		"pkt":  hex.EncodeToString(pkt),
	}).Trace("omci-end-software-download-response")

	return pkt, nil
}

func CreateActivateSoftwareResponse(omciPkt gopacket.Packet, omciMsg *omci.OMCI) ([]byte, error) {

	msgObj, err := ParseActivateSoftwareRequest(omciPkt)

	if err != nil {
		return nil, err
	}
	isExtended := false
	if omciMsg.DeviceIdentifier == omci.ExtendedIdent {
		isExtended = true
	}
	omciLogger.WithFields(log.Fields{
		"OmciMsgType":      omciMsg.MessageType,
		"TransCorrId":      omciMsg.TransactionID,
		"DeviceIdentifier": omciMsg.DeviceIdentifier,
		"EntityInstance":   msgObj.EntityInstance,
		"ActivateFlags":    msgObj.ActivateFlags,
	}).Debug("received-activate-software-request")

	response := &omci.ActivateSoftwareResponse{
		MeBasePacket: omci.MeBasePacket{
			EntityClass:    msgObj.EntityClass,
			EntityInstance: msgObj.EntityInstance,
			Extended:       isExtended,
		},
		Result: me.Success,
	}
	omciLayer := &omci.OMCI{
		TransactionID:    omciMsg.TransactionID,
		MessageType:      omci.ActivateSoftwareResponseType,
		DeviceIdentifier: omciMsg.DeviceIdentifier,
	}
	var options gopacket.SerializeOptions
	options.FixLengths = true

	buffer := gopacket.NewSerializeBuffer()
	err = gopacket.SerializeLayers(buffer, options, omciLayer, response)
	if err != nil {
		omciLogger.WithFields(log.Fields{
			"Err":  err,
			"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		}).Error("cannot-Serialize-ActivateSoftwareResponse")
		return nil, err
	}
	pkt := buffer.Bytes()

	log.WithFields(log.Fields{
		"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		"pkt":  hex.EncodeToString(pkt),
	}).Trace("omci-activate-software-response")

	return pkt, nil
}

func CreateCommitSoftwareResponse(omciPkt gopacket.Packet, omciMsg *omci.OMCI) ([]byte, error) {

	msgObj, err := ParseCommitSoftwareRequest(omciPkt)

	if err != nil {
		return nil, err
	}
	isExtended := false
	if omciMsg.DeviceIdentifier == omci.ExtendedIdent {
		isExtended = true
	}
	omciLogger.WithFields(log.Fields{
		"OmciMsgType":      omciMsg.MessageType,
		"TransCorrId":      omciMsg.TransactionID,
		"DeviceIdentifier": omciMsg.DeviceIdentifier,
		"EntityInstance":   msgObj.EntityInstance,
	}).Debug("received-commit-software-request")

	response := &omci.CommitSoftwareResponse{
		MeBasePacket: omci.MeBasePacket{
			EntityClass:    msgObj.EntityClass,
			EntityInstance: msgObj.EntityInstance,
			Extended:       isExtended,
		},
	}
	omciLayer := &omci.OMCI{
		TransactionID:    omciMsg.TransactionID,
		MessageType:      omci.CommitSoftwareResponseType,
		DeviceIdentifier: omciMsg.DeviceIdentifier,
	}
	var options gopacket.SerializeOptions
	options.FixLengths = true

	buffer := gopacket.NewSerializeBuffer()
	err = gopacket.SerializeLayers(buffer, options, omciLayer, response)
	if err != nil {
		omciLogger.WithFields(log.Fields{
			"Err":  err,
			"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		}).Error("cannot-Serialize-CommitSoftwareResponse")
		return nil, err
	}
	pkt := buffer.Bytes()

	log.WithFields(log.Fields{
		"TxID": strconv.FormatInt(int64(omciMsg.TransactionID), 16),
		"pkt":  hex.EncodeToString(pkt),
	}).Trace("omci-commit-software-response")

	return pkt, nil
}

func ComputeDownloadSectionsCount(pkt gopacket.Packet) uint32 {
	msgObj, err := ParseStartSoftwareDownloadRequest(pkt)
	if err != nil {
		omciLogger.Error("cannot-parse-start-software-download-request")
	}
	var omciDownloadSectionSize uint32
	if msgObj.Extended {
		omciDownloadSectionSize = cOmciDownloadSectionSizeExtLine
	} else {
		omciDownloadSectionSize = cOmciDownloadSectionSizeBaseLine
	}
	noOfSections := msgObj.ImageSize / omciDownloadSectionSize
	if msgObj.ImageSize%omciDownloadSectionSize > 0 {
		noOfSections++
	}
	return noOfSections
}