WasteInformationServer/src/java/com/wasteinformationserver/mqtt/MqttService.kt

package com.wasteinformationserver.mqtt

import com.wasteinformationserver.basicutils.Log
import com.wasteinformationserver.basicutils.Log.Log.debug
import com.wasteinformationserver.basicutils.Log.Log.error
import com.wasteinformationserver.basicutils.Log.Log.info
import com.wasteinformationserver.basicutils.Log.Log.message
import com.wasteinformationserver.basicutils.Log.Log.warning
import com.wasteinformationserver.db.JDBC
import org.eclipse.paho.client.mqttv3.*
import java.sql.SQLException
import java.text.ParseException
import java.text.SimpleDateFormat
import java.util.*

/**
 * Mqtt Service to receive and send back messages to the Hardware
 * check values from db send right feedback to hardware.
 *
 * @author Lukas Heiligenbrunner
 * @author Gregor Dutzler
 */
class MqttService {
    private var serveruri: String = "";
    private lateinit var client: MqttClient;
    private var db: JDBC = JDBC.getInstance()

    companion object {
        private val obj = MqttService()
        fun getInstance(): MqttService {
            return obj;
        }
    }

    fun init(serverurl: String, port: String){
        serveruri = "tcp://$serverurl:$port"
    }

    /**
     * startup of the mqtt service
     */
    fun startupService() {
        if(JDBC.isConnected()) {
            try {
                client = MqttClient(serveruri, "WasteInformationServerID")
                val connOpts = MqttConnectOptions()
                connOpts.isCleanSession = true
                client.connect(connOpts)
                client.setCallback(object : MqttCallback {
                    override fun connectionLost(throwable: Throwable) {
                        error("connection lost")
                        Thread.sleep(500)
                        // restart service
                        startupService()
                    }

                    override fun messageArrived(s: String, mqttMessage: MqttMessage) {
                        val deviceid = String(mqttMessage.payload)
                        message("received Request from PCB")
                        val res = db.executeQuery("SELECT * from devices WHERE DeviceID=$deviceid")
                        try {
                            res.last()
                            if (res.row != 0) {
                                // existing device
                                res.first()
                                val devicecities = db.executeQuery("SELECT * from device_city WHERE DeviceID='$deviceid'")
                                devicecities.last()
                                if (devicecities.row == 0) {
                                    // not configured
                                    tramsmitMessage("$deviceid,-1")
                                }
                                else {
                                    devicecities.first()
                                    devicecities.previous()

                                    while (devicecities.next()) {
                                        val cityid = devicecities.getInt("CityID")
                                        checkDatabase(cityid, deviceid.toInt())
                                    }
                                }
                            }
                            else {
                                // new device
                                db.executeUpdate("INSERT INTO devices (DeviceID) VALUES ($deviceid)")
                                info("new device registered to server")
                                tramsmitMessage("$deviceid,-1")
                            }
                        } catch (e: SQLException) {
                            e.printStackTrace()
                        }
                    }

                    override fun deliveryComplete(iMqttDeliveryToken: IMqttDeliveryToken) {}
                })
                client.subscribe("TopicIn")
            } catch (e: MqttException) {
                error("Connection to the Broker failed")
            }
        }else{
            Log.error("could't start mqtt service because of missing db connection!")
        }
    }

    /**
     * Check if device is configured and zone infos are stored in db
     *
     * @param citywastezoneid zone/city id
     * @param deviceid        device id
     */
    private fun checkDatabase(citywastezoneid: Int, deviceid: Int) {
        var wastetype = -1
        val set2 = db.executeQuery("SELECT * FROM cities WHERE `id`='$citywastezoneid'")
        try {
            set2.last()
            if (set2.row != 1) {
                //error
                warning("multiple Rows with same city id found - DB Error")
            }
            else {
                val typ = set2.getString("wastetype")
                wastetype = getIntTyp(typ)
            }
        } catch (e: SQLException) {
            e.printStackTrace()
        }
        val result = db.executeQuery("SELECT pickupdates.pickupdate FROM pickupdates WHERE pickupdates.citywastezoneid=$citywastezoneid")
        try {
            result.last()
            if (result.row == 0) {
                //if not found in db --> send zero
                debug("not found in db")
                tramsmitMessage("$deviceid,$wastetype,0")
            }
            else {
                debug(result.getString("pickupdate"))
                result.first()
                do {
                    val formatter = SimpleDateFormat("yyyy-MM-dd")
                    val timestamp = formatter.parse(result.getString("pickupdate")).time
                    val timestampnow = formatter.parse(formatter.format(Date())).time
                    debug("timestamp is :$timestamp")
                    if (timestamp == timestampnow || timestamp == timestampnow + 86400000) { // 86400000 == one day
                        // valid time
                        tramsmitMessage("$deviceid,$wastetype,1")
                        debug("valid time")
                        return
                    }
                } while (result.next())
                tramsmitMessage("$deviceid,$wastetype,0")
                //transmit zero if not returned before
            }
        } catch (e: SQLException) {
            e.printStackTrace()
        } catch (e: ParseException) {
            e.printStackTrace()
        }
    }

    /**
     * send a mqtt message to predefined topic
     */
    private fun tramsmitMessage(temp: String) {
        message("reply back to PCB: $temp")
        val message = MqttMessage(temp.toByteArray())
        message.qos = 2
        try {
            client.publish("TopicOut", message)
        } catch (e: MqttException) {
            e.printStackTrace()
        }
    }

    /**
     * parse Type name to representing integer value
     */
    private fun getIntTyp(temp: String): Int {
        return when (temp) {
            "Plastic" -> 1
            "Metal" -> 2
            "Residual waste" -> 3
            "Biowaste" -> 4
            else -> 0
        }
    }
}