Cleaning up the api.

Bootstrap/dewPoint-env-example

@@ -4,5 +4,11 @@
   "MQTT_PORT": "1883",
   "MQTT_IDENTIFIER": "dewPoint-controller",
   "MQTT_USERNAME": "mqtt_user",
-  "MQTT_PASSWORD": "secret!"
+  "MQTT_PASSWORD": "secret!",
+  "DEHUMIDIFICATION_STAGE_1_RELAY": "relays/dehumidification_1",
+  "DEHUMIDIFICATION_STAGE_2_RELAY": "relays/dehumidification_2",
+  "DEW_POINT_TOPIC": "sensors/dew_point",
+  "HUMIDIFICATION_RELAY": "relays/humidification",
+  "HUMIDITY_SENSOR": "sensors/humidity",
+  "TEMPERATURE_SENSOR": "sensors/temperature"
 }

Package.swift

@@ -40,6 +40,7 @@ let package = Package(
         "DewPointEnvironment",
         "EnvVars",
         "ClientLive",
+        "Models",
         .product(name: "MQTTNIO", package: "mqtt-nio"),
         .product(name: "NIO", package: "swift-nio")
       ]
@@ -49,6 +50,7 @@ let package = Package(
       dependencies: [
         "EnvVars",
         "Client",
+        "Models",
         .product(name: "MQTTNIO", package: "mqtt-nio"),
       ]
     ),
@@ -58,7 +60,9 @@ let package = Package(
     ),
     .target(
       name: "Models",
-      dependencies: []
+      dependencies: [
+        .product(name: "CoreUnitTypes", package: "swift-psychrometrics"),
+      ]
     ),
     .target(
       name: "Client",

Sources/Bootstrap/Bootstrap.swift

@@ -3,30 +3,32 @@ import DewPointEnvironment
 import EnvVars
 import Logging
 import Foundation
+import Models
 import MQTTNIO
 import NIO
 
+/// Sets up the application environment and connections required.
+///
+/// - Parameters:
+///   - eventLoopGroup: The event loop group for the application.
+///   - logger: An optional logger for debugging.
 public func bootstrap(
   eventLoopGroup: EventLoopGroup,
   logger: Logger? = nil
 ) -> EventLoopFuture<DewPointEnvironment> {
+  
   logger?.debug("Bootstrapping Dew Point Controller...")
+  
   return loadEnvVars(eventLoopGroup: eventLoopGroup, logger: logger)
-    .map { (envVars) -> DewPointEnvironment in
-      let mqttClient = MQTTClient(envVars: envVars, eventLoopGroup: eventLoopGroup, logger: logger)
-      return DewPointEnvironment.init(
-        client: .live(client: mqttClient),
-        envVars: envVars,
-        mqttClient: mqttClient
-      )
-    }
-    .flatMap { environment in
-      environment.mqttClient.logger.debug("Connecting to MQTT broker...")
-      return environment.mqttClient.connect()
-        .map { _ in environment }
-    }
+    .makeDewPointEnvironment(eventLoopGroup: eventLoopGroup, logger: logger)
+    .connectToMQTTBroker(logger: logger)
 }
 
+/// Loads the ``EnvVars`` either using the defualts, from a file in the root directory under `.dewPoint-env` or in the shell / application environment.
+///
+/// - Parameters:
+///   - eventLoopGroup: The event loop group for the application.
+///   - logger: An optional logger for debugging.
 private func loadEnvVars(eventLoopGroup: EventLoopGroup, logger: Logger?) -> EventLoopFuture<EnvVars> {
   
   logger?.debug("Loading env vars...")
@@ -66,6 +68,49 @@ private func loadEnvVars(eventLoopGroup: EventLoopGroup, logger: Logger?) -> Eve
   return eventLoopGroup.next().makeSucceededFuture(envVars)
 }
 
+extension EventLoopFuture where Value == EnvVars {
+  
+  /// Creates the ``DewPointEnvironment`` for the application after the ``EnvVars`` have been loaded.
+  ///
+  ///  - Parameters:
+  ///   - eventLoopGroup: The event loop group for the application.
+  ///   - logger: An optional logger for the application.
+  fileprivate func makeDewPointEnvironment(
+    eventLoopGroup: EventLoopGroup,
+    logger: Logger?
+  ) -> EventLoopFuture<DewPointEnvironment> {
+      map { envVars in
+        let nioClient = MQTTClient(envVars: envVars, eventLoopGroup: eventLoopGroup, logger: logger)
+        return DewPointEnvironment.init(
+          mqttClient: .live(client: nioClient),
+          envVars: envVars,
+          nioClient: nioClient,
+          topics: .init(envVars: envVars)
+        )
+      }
+  }
+}
+
+extension EventLoopFuture where Value == DewPointEnvironment {
+  
+  /// Connects to the MQTT broker after the ``DewPointEnvironment`` has been setup.
+  ///
+  /// - Parameters:
+  ///   - logger: An optional logger for debugging.
+  fileprivate func connectToMQTTBroker(logger: Logger?) -> EventLoopFuture<DewPointEnvironment> {
+    flatMap { environment in
+      logger?.debug("Connecting to MQTT Broker...")
+      return environment.nioClient.connect()
+        .map { _ in
+          logger?.debug("Successfully connected to MQTT Broker...")
+          return environment
+        }
+    }
+  }
+}
+
+// MARK: - Helpers
+
 extension MQTTClient {
   
   convenience init(envVars: EnvVars, eventLoopGroup: EventLoopGroup, logger: Logger?) {
@@ -83,3 +128,22 @@ extension MQTTClient {
     )
   }
 }
+
+// MARK: - TODO Make topics loadable from a file in the root directory.
+extension Topics {
+  
+  init(envVars: EnvVars) {
+    self.init(
+      sensors: .init(
+        temperature: envVars.temperatureSensor,
+        humidity: envVars.humiditySensor,
+        dewPoint: envVars.dewPointTopic
+      ),
+      relays: .init(
+        dehumidification1: envVars.dehumidificationStage1Relay,
+        dehumidification2: envVars.dehumidificationStage2Relay,
+        humidification: envVars.humidificationRelay
+      )
+    )
+  }
+}

Sources/Client/Interface.swift

@@ -5,42 +5,80 @@ import Models
 import NIO
 import Psychrometrics
 
-public struct Client {
+/// Represents the applications interactions with the MQTT Broker.
+///
+/// This is an abstraction around the ``MQTTNIO.MQTTClient``.
+public struct MQTTClient {
   
-  public var fetchHumidity: (HumiditySensor) -> EventLoopFuture<RelativeHumidity>
-  public var fetchTemperature: (TemperatureSensor, PsychrometricEnvironment.Units?) -> EventLoopFuture<Temperature>
-  public var toggleRelay: (Relay) -> EventLoopFuture<Void>
-  public var turnOnRelay: (Relay) -> EventLoopFuture<Void>
-  public var turnOffRelay: (Relay) -> EventLoopFuture<Void>
+  /// Retrieve the humidity from the MQTT Broker.
+  public var fetchHumidity: (Sensor<RelativeHumidity>) -> EventLoopFuture<RelativeHumidity>
+  
+  /// Retrieve the temperature from the MQTT Broker.
+  public var fetchTemperature: (Sensor<Temperature>, PsychrometricEnvironment.Units?) -> EventLoopFuture<Temperature>
+  
+  /// Publish a change of state message for a relay.
+  public var setRelay: (Relay, Relay.State) -> EventLoopFuture<Void>
+  
+  /// Disconnect and close the connection to the MQTT Broker.
   public var shutdown: () -> EventLoopFuture<Void>
   
+  /// Publish the current dew point to the MQTT Broker
+  public var publishDewPoint: (DewPoint, String) -> EventLoopFuture<Void>
+  
   public init(
-    fetchHumidity: @escaping (HumiditySensor) -> EventLoopFuture<RelativeHumidity>,
-    fetchTemperature: @escaping (TemperatureSensor, PsychrometricEnvironment.Units?) -> EventLoopFuture<Temperature>,
-    toggleRelay: @escaping (Relay) -> EventLoopFuture<Void>,
-    turnOnRelay: @escaping (Relay) -> EventLoopFuture<Void>,
-    turnOffRelay: @escaping (Relay) -> EventLoopFuture<Void>,
-    shutdown: @escaping () -> EventLoopFuture<Void>
+    fetchHumidity: @escaping (Sensor<RelativeHumidity>) -> EventLoopFuture<RelativeHumidity>,
+    fetchTemperature: @escaping (Sensor<Temperature>, PsychrometricEnvironment.Units?) -> EventLoopFuture<Temperature>,
+    setRelay: @escaping (Relay, Relay.State) -> EventLoopFuture<Void>,
+    shutdown: @escaping () -> EventLoopFuture<Void>,
+    publishDewPoint: @escaping (DewPoint, String) -> EventLoopFuture<Void>
   ) {
     self.fetchHumidity = fetchHumidity
     self.fetchTemperature = fetchTemperature
-    self.toggleRelay = toggleRelay
-    self.turnOnRelay = turnOnRelay
-    self.turnOffRelay = turnOffRelay
+    self.setRelay = setRelay
     self.shutdown = shutdown
+    self.publishDewPoint = publishDewPoint
   }
   
-  public func fetchDewPoint(
-    temperature: TemperatureSensor,
-    humidity: HumiditySensor,
-    units: PsychrometricEnvironment.Units? = nil,
-    logger: Logger? = nil
+  /// Fetches the current temperature and humidity and calculates the current dew point.
+  ///
+  /// - Parameters:
+  ///   - temperature: The temperature sensor to fetch the temperature from.
+  ///   - humidity: The humidity sensor to fetch the humidity from.
+  ///   - units: Optional units for the dew point.
+  public func currentDewPoint(
+    temperature: Sensor<Temperature>,
+    humidity: Sensor<RelativeHumidity>,
+    units: PsychrometricEnvironment.Units? = nil
   ) -> EventLoopFuture<DewPoint> {
     fetchTemperature(temperature, units)
       .and(fetchHumidity(humidity))
-      .map { temp, humidity in
-        logger?.debug("Creating dew-point for temperature: \(temp) with humidity: \(humidity)")
-        return DewPoint.init(dryBulb: temp, humidity: humidity, units: units)
-      }
+      .convertToDewPoint(units: units)
+  }
+  
+  /// Convenience to send a change of state message to a relay.
+  ///
+  /// - Parameters:
+  ///   - relay: The relay to send the message to.
+  ///   - state: The state to change the relay to.
+  public func `set`(relay: Relay, to state: Relay.State) -> EventLoopFuture<Void> {
+    setRelay(relay, state)
+  }
+  
+  /// Convenience to publish the current dew point back to the MQTT Broker.
+  ///
+  /// This is synactic sugar around ``MQTTClient.publishDewPoint``.
+  ///
+  /// - Parameters:
+  ///   - dewPoint: The dew point value to publish.
+  ///   - topic: The dew point topic to publish to.
+  public func publish(dewPoint: DewPoint, to topic: String) -> EventLoopFuture<Void> {
+    publishDewPoint(dewPoint, topic)
+  }
+}
+
+extension EventLoopFuture where Value == (Temperature, RelativeHumidity) {
+  
+  fileprivate func convertToDewPoint(units: PsychrometricEnvironment.Units?) -> EventLoopFuture<DewPoint> {
+    map { .init(dryBulb: $0, humidity: $1, units: units) }
   }
 }

Sources/ClientLive/Helpers.swift

@@ -0,0 +1,139 @@
+import CoreUnitTypes
+import Models
+import MQTTNIO
+import NIO
+
+/// Represents a type that can be initialized by a ``ByteBuffer``.
+protocol BufferInitalizable {
+  init?(buffer: inout ByteBuffer)
+}
+
+extension Temperature: BufferInitalizable {
+  
+  init?(buffer: inout ByteBuffer) {
+    guard let string = buffer.readString(length: buffer.readableBytes, encoding: .utf8),
+            let value = Double(string)
+    else {
+      return nil
+    }
+    self.init(value, units: .celsius)
+  }
+}
+
+extension RelativeHumidity: BufferInitalizable {
+  
+  init?(buffer: inout ByteBuffer) {
+    guard let string = buffer.readString(length: buffer.readableBytes, encoding: .utf8),
+          let value = Double(string)
+    else {
+      return nil
+    }
+    self.init(value)
+  }
+}
+
+/// Represents errors thrown while communicating with the MQTT Broker.
+enum MQTTError: Error {
+  
+  /// Sensor error.
+  case sensor(reason: String, error: Error?)
+  
+  /// Relay error.
+  case relay(reason: String, error: Error?)
+}
+
+extension MQTTNIO.MQTTClient {
+  
+  /// Fetch a sensor state and convert it appropriately, when the sensor type is ``BufferInitializable``.
+  ///
+  /// - Parameters:
+  ///   - sensor: The sensor to fetch the state of.
+  func fetch<S>(
+    sensor: Sensor<S>
+  ) -> EventLoopFuture<S> where S: BufferInitalizable {
+    logger.debug("Fetching data for sensor: \(sensor.topic)")
+    let subscription = MQTTSubscribeInfoV5.init(
+      topicFilter: sensor.topic,
+      qos: .atLeastOnce,
+      retainAsPublished: true,
+      retainHandling: .sendAlways
+    )
+    return v5.subscribe(to: [subscription])
+      .flatMap { _ in
+        let promise = self.eventLoopGroup.next().makePromise(of: S.self)
+        self.addPublishListener(named: sensor.topic) { result in
+          
+          result.mapBuffer(to: S.self)
+            .unwrap(or: MQTTError.sensor(reason: "Invalid sensor reading", error: nil))
+            .fullfill(promise: promise)
+          
+          self.logger.debug("Done fetching data for sensor: \(sensor.topic)")
+        }
+        
+        return promise.futureResult
+      }
+  }
+  
+  func `set`(relay: Relay, to state: Relay.State, qos: MQTTQoS = .atLeastOnce) -> EventLoopFuture<Void> {
+    publish(
+      to: relay.topic,
+      payload: ByteBufferAllocator().buffer(string: state.rawValue),
+      qos: qos
+    )
+  }
+}
+
+extension Result where Success == MQTTPublishInfo, Failure == Error {
+  
+  func mapBuffer<S>(to type: S.Type) -> Result<S?, Error> where S: BufferInitalizable {
+    map { info in
+      var buffer = info.payload
+      return S.init(buffer: &buffer)
+    }
+  }
+}
+
+extension Result {
+  
+  func fullfill(promise: EventLoopPromise<Success>) {
+    switch self {
+    case let.success(value):
+      promise.succeed(value)
+    case let .failure(error):
+      promise.fail(error)
+    }
+  }
+  
+}
+
+extension Result where Failure == Error {
+  
+  func unwrap<S, F>(
+    or error: @autoclosure @escaping () -> F
+  ) -> Result<S, Error> where Success == Optional<S>, Failure == F {
+    flatMap { optionalResult in
+      guard let value = optionalResult else {
+        return .failure(error())
+      }
+      return .success(value)
+    }
+  }
+}
+
+extension Temperature {
+  
+  func convert(to units: PsychrometricEnvironment.Units) -> Self {
+    let temperatureUnits = Units.defaultFor(units: units)
+    return .init(self[temperatureUnits], units: temperatureUnits)
+  }
+}
+
+extension EventLoopFuture where Value == Temperature {
+  
+  func convertIfNeeded(to units: PsychrometricEnvironment.Units?) -> EventLoopFuture<Temperature> {
+    map { currentTemperature in
+      guard let units = units else { return currentTemperature }
+      return currentTemperature.convert(to: units)
+    }
+  }
+}

Sources/ClientLive/Live.swift

@@ -5,135 +5,35 @@ import Models
 import MQTTNIO
 import NIO
 
-extension Client {
+extension Client.MQTTClient {
   
-  public static func live(client: MQTTClient) -> Self {
+  /// Creates the live implementation of our ``Client.MQTTClient`` for the application.
+  ///
+  /// - Parameters:
+  ///   - client: The ``MQTTNIO.MQTTClient`` used to send and recieve messages from the MQTT Broker.
+  public static func live(client: MQTTNIO.MQTTClient) -> Self {
     .init(
       fetchHumidity: { sensor in
-        client.fetchHumidity(sensor: sensor)
+        client.fetch(sensor: sensor)
       },
       fetchTemperature: { sensor, units in
-        client.fetchTemperature(sensor: sensor, units: units)
+        client.fetch(sensor: sensor)
+          .convertIfNeeded(to: units)
       },
-      toggleRelay: { relay in
-        client.publish(relay: relay, state: .toggle, qos: .atLeastOnce)
-      },
-      turnOnRelay: { relay in
-        client.publish(relay: relay, state: .on, qos: .atLeastOnce)
-      },
-      turnOffRelay: { relay in
-        client.publish(relay: relay, state: .off, qos: .atLeastOnce)
+      setRelay: { relay, state in
+        client.set(relay: relay, to: state)
       },
       shutdown: {
         client.disconnect()
+          .map { try? client.syncShutdownGracefully() }
+      },
+      publishDewPoint: { dewPoint, topic in
+        client.publish(
+          to: topic,
+          payload: ByteBufferAllocator().buffer(string: "\(dewPoint.rawValue)"),
+          qos: .atLeastOnce
+        )
       }
     )
   }
 }
-
-// MARK: - Helpers
-enum TemperatureError: Error {
-  case invalidTemperature
-}
-
-enum HumidityError: Error {
-  case invalidHumidity
-}
-
-extension Relay {
-  enum State: String {
-    case toggle, on, off
-  }
-}
-
-extension MQTTClient {
-  
-  fileprivate func publish(relay: Relay, state: Relay.State, qos: MQTTQoS = .atLeastOnce) -> EventLoopFuture<Void> {
-    publish(
-      to: relay.topic,
-      payload: ByteBufferAllocator().buffer(string: state.rawValue),
-      qos: qos
-    )
-  }
-  
-  // MARK: - TODO it feels like the subscriptions should happen in the `bootstrap` process.
-  fileprivate func fetchTemperature(
-    sensor: TemperatureSensor,
-    units: PsychrometricEnvironment.Units?
-  ) -> EventLoopFuture<Temperature> {
-    logger.debug("Adding listener for temperature sensor...")
-    let subscription = MQTTSubscribeInfoV5.init(
-      topicFilter: sensor.topic,
-      qos: .atLeastOnce,
-      retainAsPublished: true,
-      retainHandling: .sendAlways
-    )
-    return v5.subscribe(to: [subscription])
-      .flatMap { _ in
-        let promise = self.eventLoopGroup.next().makePromise(of: Temperature.self)
-        self.addPublishListener(named: "temperature-sensor", { result in
-          switch result.temperature() {
-          case let .success(celsius):
-            let userUnits = units ?? PsychrometricEnvironment.shared.units
-            let temperatureUnits = Temperature.Units.defaultFor(units: userUnits)
-            promise.succeed(.init(celsius[temperatureUnits], units: temperatureUnits))
-          case let .failure(error):
-            promise.fail(error)
-          }
-        })
-        
-        return promise.futureResult
-      }
-  }
-  
-  // MARK: - TODO it feels like the subscriptions should happen in the `bootstrap` process.
-  fileprivate func fetchHumidity(sensor: HumiditySensor) -> EventLoopFuture<RelativeHumidity> {
-    logger.debug("Adding listener for humidity sensor...")
-    let subscription = MQTTSubscribeInfoV5.init(
-      topicFilter: sensor.topic,
-      qos: .atLeastOnce,
-      retainAsPublished: true,
-      retainHandling: .sendAlways
-    )
-    return v5.subscribe(to: [subscription])
-      .flatMap { _ in
-        let promise = self.eventLoopGroup.next().makePromise(of: RelativeHumidity.self)
-        self.addPublishListener(named: "humidity-sensor", { result in
-          switch result.humidity() {
-          case let .success(humidity):
-            promise.succeed(humidity)
-          case let .failure(error):
-            promise.fail(error)
-          }
-        })
-        return promise.futureResult
-      }
-  }
-}
-
-extension Result where Success == MQTTPublishInfo, Failure == Error {
-  
-  fileprivate func humidity() -> Result<RelativeHumidity, Error> {
-    flatMap { info in
-      var buffer = info.payload
-      guard let string = buffer.readString(length: buffer.readableBytes),
-            let double = Double(string)
-      else {
-        return .failure(HumidityError.invalidHumidity)
-      }
-      return .success(.init(double))
-    }
-  }
-  
-  fileprivate func temperature() -> Result<Temperature, Error> {
-    flatMap { info in
-      var buffer = info.payload
-      guard let string = buffer.readString(length: buffer.readableBytes),
-            let temperatureValue = Double(string)
-      else {
-        return .failure(TemperatureError.invalidTemperature)
-      }
-      return .success(.celsius(temperatureValue))
-    }
-  }
-}

Sources/DewPointEnvironment/Environment.swift

@@ -1,20 +1,24 @@
 import Client
 import EnvVars
+import Models
 import MQTTNIO
 
 public struct DewPointEnvironment {
   
-  public var client: Client
+  public var mqttClient: Client.MQTTClient
   public var envVars: EnvVars
-  public var mqttClient: MQTTClient
+  public var nioClient: MQTTNIO.MQTTClient
+  public var topics: Topics
   
   public init(
-    client: Client,
+    mqttClient: Client.MQTTClient,
     envVars: EnvVars,
-    mqttClient: MQTTClient
+    nioClient: MQTTNIO.MQTTClient,
+    topics: Topics = .init()
   ) {
     self.mqttClient = mqttClient
     self.envVars = envVars
-    self.client = client
+    self.nioClient = nioClient
+    self.topics = topics
   }
 }

Sources/EnvVars/EnvVars.swift

@@ -24,6 +24,15 @@ public struct EnvVars: Codable, Equatable {
   /// The MQTT user password.
   public var password: String?
   
+  // MARK: TODO Move Topics to their own file that can be loaded.
+  // Topics
+  public var dehumidificationStage1Relay: String
+  public var dehumidificationStage2Relay: String
+  public var dewPointTopic: String
+  public var humidificationRelay: String
+  public var humiditySensor: String
+  public var temperatureSensor: String
+  
   /// Create a new ``EnvVars``
   ///
   /// - Parameters:
@@ -39,7 +48,13 @@ public struct EnvVars: Codable, Equatable {
     port: String? = "1883",
     identifier: String = "dewPoint-controller",
     userName: String? = "mqtt_user",
-    password: String? = "secret!"
+    password: String? = "secret!",
+    dehumidificationStage1Relay: String = "relays/dehumidification_1",
+    dehumidificationStage2Relay: String = "relays/dehumidification_2",
+    dewPointTopic: String = "sensors/dew_point",
+    humidificationRelay: String = "relays/humidification",
+    humiditySensor: String = "sensors/humidity",
+    temperatureSensor: String = "sensors/temperature"
   ){
     self.appEnv = appEnv
     self.host = host
@@ -47,6 +62,12 @@ public struct EnvVars: Codable, Equatable {
     self.identifier = identifier
     self.userName = userName
     self.password = password
+    self.dehumidificationStage1Relay = dehumidificationStage1Relay
+    self.dehumidificationStage2Relay = dehumidificationStage2Relay
+    self.dewPointTopic = dewPointTopic
+    self.humidificationRelay = humidificationRelay
+    self.humiditySensor = humiditySensor
+    self.temperatureSensor = temperatureSensor
   }
   
   /// Custom coding keys.
@@ -57,6 +78,12 @@ public struct EnvVars: Codable, Equatable {
     case identifier = "MQTT_IDENTIFIER"
     case userName = "MQTT_USERNAME"
     case password = "MQTT_PASSWORD"
+    case dehumidificationStage1Relay = "DEHUMIDIFICATION_STAGE_1_RELAY"
+    case dehumidificationStage2Relay = "DEHUMIDIFICATION_STAGE_2_RELAY"
+    case dewPointTopic = "DEW_POINT_TOPIC"
+    case humidificationRelay = "HUMIDIFICATION_RELAY"
+    case humiditySensor = "HUMIDITY_SENSOR"
+    case temperatureSensor = "TEMPERATURE_SENSOR"
   }
   
   /// Represents the different app environments.

Sources/Models/HumiditySensor.swift

@@ -1,8 +0,0 @@
-
-public struct HumiditySensor: Equatable {
-  public var topic: String
-  
-  public init(topic: String) {
-    self.topic = topic
-  }
-}

Sources/Models/Mode.swift

@@ -0,0 +1,37 @@
+import CoreUnitTypes
+
+/// Represents the different modes that the controller can be in.
+public enum Mode: Equatable {
+  
+  /// Allows controller to run in humidify or dehumidify mode.
+  case auto
+  
+  /// Only handle humidify mode.
+  case humidifyOnly(HumidifyMode)
+  
+  /// Only handle dehumidify mode.
+  case dehumidifyOnly(DehumidifyMode)
+  
+  /// Don't control humidify or dehumidify modes.
+  case off
+  
+  /// Represents the control modes for the humidify control state.
+  public enum HumidifyMode: Equatable {
+    
+    /// Control humidifying based off dew-point.
+    case dewPoint(Temperature)
+    
+    /// Control humidifying based off relative humidity.
+    case relativeHumidity(RelativeHumidity)
+  }
+  
+  /// Represents the control modes for the dehumidify control state.
+  public enum DehumidifyMode: Equatable {
+    
+    /// Control dehumidifying based off dew-point.
+    case dewPoint(high: Temperature, low: Temperature)
+    
+    /// Control humidifying based off relative humidity.
+    case relativeHumidity(high: RelativeHumidity, low: RelativeHumidity)
+  }
+}

Sources/Models/Relay.swift

@@ -1,8 +1,40 @@
 
+/// Represents a relay that can be controlled by the MQTT Broker.
 public struct Relay {
+  
+  /// The topic for the relay.
   public var topic: String
   
+  /// Create a new relay at the given topic.
+  ///
+  /// - Parameters:
+  ///   - topic: The topic for commanding the relay.
   public init(topic: String) {
     self.topic = topic
   }
 }
+
+public enum Relay2 {
+  
+  /// The topic to read the current state of the relay from.
+  case read(topic: String)
+  
+  /// The topic to command the relay state.
+  case command(topic: String)
+}
+
+extension Relay {
+  
+  /// Represents the different commands that can be sent to a relay.
+  public enum State: String {
+    
+    /// Toggle the relay state on or off based on it's current state.
+    case toggle
+    
+    /// Turn the relay off.
+    case off
+    
+    /// Turn the relay on.
+    case on
+  }
+}

Sources/Models/Sensor.swift

@@ -0,0 +1,15 @@
+
+/// Represents a sensor that provides a reading.
+public struct Sensor<Reading>: Equatable {
+  
+  /// The topic to retrieve the reading from.
+  public var topic: String
+  
+  /// Create a new sensor for the given topic.
+  ///
+  /// - Parameters:
+  ///   - topic: The topic to retrieve the readings from.
+  public init(topic: String) {
+    self.topic = topic
+  }
+}

Sources/Models/TemperatureSensor.swift

@@ -1,8 +0,0 @@
-
-public struct TemperatureSensor: Equatable {
-  public var topic: String
-  
-  public init(topic: String) {
-    self.topic = topic
-  }
-}

Sources/Models/Topics.swift

@@ -0,0 +1,91 @@
+public struct Topics {
+  
+  public var sensors: Sensors
+  public var setPoints: SetPoints
+  public var states: States
+  public var relays: Relays
+  
+  public init(
+    sensors: Sensors = .init(),
+    setPoints: SetPoints = .init(),
+    states: States = .init(),
+    relays: Relays = .init()
+  ) {
+    self.sensors = sensors
+    self.setPoints = setPoints
+    self.states = states
+    self.relays = relays
+  }
+  
+  public struct Sensors {
+    public var temperature: String
+    public var humidity: String
+    public var dewPoint: String
+    
+    public init(
+      temperature: String = "sensors/temperature",
+      humidity: String = "sensors/humidity",
+      dewPoint: String = "sensors/dew_point"
+    ) {
+      self.temperature = temperature
+      self.humidity = humidity
+      self.dewPoint = dewPoint
+    }
+  }
+  
+  public struct SetPoints {
+    public var humidify: String
+    public var dehumidify: Dehumidify
+    
+    public init(
+      humidify: String = "set_points/humidify",
+      dehumidify: Dehumidify = .init()
+    ) {
+      self.humidify = humidify
+      self.dehumidify = dehumidify
+    }
+    
+    public struct Dehumidify {
+      public var lowDewPoint: String
+      public var highDewPoint: String
+      public var lowRelativeHumidity: String
+      public var highRelativeHumidity: String
+      
+      public init(
+        lowDewPoint: String = "set_points/dehumidify/low_dew_point",
+        highDewPoint: String = "set_points/dehumidify/high_dew_point",
+        lowRelativeHumidity: String = "set_points/dehumidify/low_relative_humidity",
+        highRelativeHumidity: String = "set_points/dehumidify/high_relative_humidity"
+      ) {
+        self.lowDewPoint = lowDewPoint
+        self.highDewPoint = highDewPoint
+        self.lowRelativeHumidity = lowRelativeHumidity
+        self.highRelativeHumidity = highRelativeHumidity
+      }
+    }
+  }
+  
+  public struct States {
+    public var mode: String
+    
+    public init(mode: String = "states/mode") {
+      self.mode = mode
+    }
+  }
+  
+  public struct Relays {
+    public var dehumidification1: String
+    public var dehumidification2: String
+    public var humidification: String
+    
+    public init(
+      dehumidification1: String = "relays/dehumidification_1",
+      dehumidification2: String = "relays/dehumidification_2",
+      humidification: String = "relays/humidification"
+    ) {
+      self.dehumidification1 = dehumidification1
+      self.dehumidification2 = dehumidification2
+      self.humidification = humidification
+    }
+  }
+}

Sources/dewPoint-controller/main.swift

@@ -1,46 +1,54 @@
 import Bootstrap
+import CoreUnitTypes
 import Logging
 import Models
 import MQTTNIO
 import NIO
 import Foundation
 
-var logger = Logger(label: "dewPoint-logger")
-logger.logLevel = .debug
-logger.debug("Swift Dew Point Controller!")
+var logger: Logger = {
+  var logger = Logger(label: "dewPoint-logger")
+  logger.logLevel = .info
+  return logger
+}()
+
+logger.info("Starting Swift Dew Point Controller!")
 
 let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
 let environment = try bootstrap(eventLoopGroup: eventLoopGroup, logger: logger).wait()
-let relay = Relay(topic: "frankensystem/relays/switch/relay_1/command")
-let tempSensor = TemperatureSensor(topic: "frankensystem/relays/sensor/temperature_-_1/state")
-let humiditySensor = HumiditySensor(topic: "frankensystem/relays/sensor/humidity_-_1/state")
+
+// Set the log level to info only in production mode.
+if environment.envVars.appEnv == .production {
+  logger.logLevel = .info
+}
+
+let relay = Relay(topic: environment.topics.relays.dehumidification1)
+let tempSensor = Sensor<Temperature>(topic: environment.topics.sensors.temperature)
+let humiditySensor = Sensor<RelativeHumidity>(topic: environment.topics.sensors.humidity)
 
 defer {
   logger.debug("Disconnecting")
-  _ = try? environment.client.shutdown().wait()
-  try? environment.mqttClient.syncShutdownGracefully()
+  try? environment.mqttClient.shutdown().wait()
 }
 
 while true {
-//  logger.debug("Toggling relay.")
-//  _ = try environment.client.toggleRelay(relay).wait()
-  
-//  logger.debug("Reading temperature sensor.")
-//  let temp = try environment.client.fetchTemperature(tempSensor, .imperial).wait()
-//  logger.debug("Temperature: \(temp)")
-  
-//  logger.debug("Reading humidity sensor.")
-//  let humidity = try environment.client.fetchHumidity(humiditySensor).wait()
-//  logger.debug("Humdity: \(humidity)")
   
   logger.debug("Fetching dew point...")
-  let dp = try environment.client.fetchDewPoint(
+  
+  let dp = try environment.mqttClient.currentDewPoint(
     temperature: tempSensor,
     humidity: humiditySensor,
-    units: .imperial,
-    logger: logger
+    units: .imperial
   ).wait()
-  logger.debug("Dew Point: \(dp)")
+  
+  logger.info("Dew Point: \(dp.rawValue) \(dp.units.symbol)")
+  
+  try environment.mqttClient.publish(
+    dewPoint: dp,
+    to: environment.topics.sensors.dewPoint
+  ).wait()
+  
+  logger.debug("Published dew point...")
   
   Thread.sleep(forTimeInterval: 5)
 }