/*
 * 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 core

import (
	"fmt"
	log "github.com/sirupsen/logrus"
)

var omciCh = make(chan OmciChMessage, 4096)

func GetChannel() chan OmciChMessage {
	return omciCh
}

func OmciSim(intfId uint32, onuId uint32, request []byte) ([]byte, error) {
	var resp []byte

	transactionId, deviceId, msgType, class, instance, content, err := ParsePkt(request)
	if err != nil {
		log.WithFields(log.Fields{
			"IntfId": intfId,
			"OnuId": onuId,
		}).Errorf("Cannot parse OMCI msg")
		return resp, &OmciError{"Cannot parse OMCI msg"}
	}

	log.WithFields(log.Fields{
		"IntfId": intfId,
		"OnuId": onuId,
		"TransactionId": transactionId,
		"MessageType": msgType.PrettyPrint(),
		"MeClass": class,
		"MeInstance": instance,
		//"Conent": content,
		"omciMsg": fmt.Sprintf("%x", content),
	}).Tracef("Processing OMCI packet")

	key := OnuKey{intfId, onuId}
	OnuOmciStateMapLock.Lock()
	if _, ok := OnuOmciStateMap[key]; !ok {
		OnuOmciStateMap[key] = NewOnuOmciState()
	}
	OnuOmciStateMapLock.Unlock()

	if _, ok := Handlers[msgType]; !ok {
		log.WithFields(log.Fields{
			"IntfId": intfId,
			"OnuId": onuId,
			"msgType": msgType,
		}).Errorf("Ignoring omci msg (msgType %d not handled)", msgType)
		return resp, &OmciError{"Unimplemented omci msg"}
	}

	resp, err = Handlers[msgType](class, content, key)
	if err != nil {
		log.WithFields(log.Fields{
			"IntfId": intfId,
			"OnuId": onuId,
			"msgType": msgType,
		}).Errorf("Unable to send a successful response, error: %s", err)
		return resp, nil
	}

	// In the OMCI message, first 2-bytes is the Transaction Correlation ID
	resp[0] = byte(transactionId >> 8)
	resp[1] = byte(transactionId & 0xFF)
	resp[2] = 0x2<<4 | byte(msgType) // Upper nibble 0x2 is fixed (0010), Lower nibbles defines the msg type (i.e., mib-upload, mib-upload-next, etc)
	resp[3] = deviceId

	// for create, get and set
	if ((msgType & 0xFF) != MibUploadNext) && ((msgType & 0xFF) != MibReset) && ((msgType & 0xFF) != MibUpload) {
		// Common fields for create, get, and set
		resp[4] = byte(class >> 8)
		resp[5] = byte(class & 0xFF)
		resp[6] = byte(instance >> 8)
		resp[7] = byte(instance & 0xFF)
		resp[8] = 0 // Result: Command Processed Successfully

		// Hardcoding class specific values for Get
		if (class == 0x82) && ((msgType & 0x0F) == Get) {
			resp[9] = 0
			resp[10] = 0x78

		} else if (class == 0x2F) && ((msgType & 0x0F) == Get) {
			resp[9] = 0x0F
			resp[10] = 0xB8
		} else if (class == 0x138) && ((msgType & 0x0F) == Get) {
			resp[9] = content[0] // 0xBE
			resp[10] = 0x00
		}
	}

	if (class == 11 && instance == 257 && msgType == Set) {
		// This is a set on a PPTP instance 257 (lan port 1)
		// Determine if its setting admin up or down and alarm appropriately

		// attrmask for what specifically sets/gets is 2 bytes
		attrmask := content[0:2]
		// actual content is the rest, as specified by attrmask.  but for this case we are only interested in 1 byte
		firstattr := content[2:3]

		// attribute bit 5 (admin state) in the PPTP is being set, its value is 1, lock
		if (attrmask[0] == 0x08 && firstattr[0] == 0x01) {
			log.Info("Send UNI Link Down Alarm on OMCI Sim channel")

			linkMsgDown := []byte{
				0x00, 0x00, 0x10, 0x0a, 0x00, 0x0b, 0x01, 0x01,
				0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}

			msg := OmciChMessage{
				Type: UniLinkDown,
				Data: OmciChMessageData{
					OnuId:  key.OnuId,
					IntfId: key.IntfId,
				},
				Packet: linkMsgDown,
			}
			omciCh <- msg

			OnuOmciStateMapLock.Lock()
			if OnuOmciState, ok := OnuOmciStateMap[key]; ok {
				OnuOmciState.state = LOCKED
			}
			OnuOmciStateMapLock.Unlock()
		}

		// attribute bit 5 (admin state) in the PPTP is being set, its value is 0, unlock
		if (attrmask[0] == 0x08 && firstattr[0] == 0x00) {
			log.Info("Send UNI Link Up Alarm on OMCI Sim channel")

			linkMsgUp := []byte{
				0x00, 0x00, 0x10, 0x0a, 0x00, 0x0b, 0x01, 0x01,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
				0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}

			msg := OmciChMessage{
				Type: UniLinkUp,
				Data: OmciChMessageData{
					OnuId:  key.OnuId,
					IntfId: key.IntfId,
				},
				Packet: linkMsgUp,
			}
			omciCh <- msg

			OnuOmciStateMapLock.Lock()
			if OnuOmciState, ok := OnuOmciStateMap[key]; ok {
				OnuOmciState.state = DONE
			}
			OnuOmciStateMapLock.Unlock()
		}
	}

	log.WithFields(log.Fields{
		"IntfId": intfId,
		"OnuId": onuId,
		"msgType": msgType.PrettyPrint(),
		"omciMsg": fmt.Sprintf("%x", resp),
	}).Tracef("OMCI-SIM Response")

	return resp, nil
}