import Foundation

/// Holds common settings for connecting to your MQTT broker.  The default values can be used,
/// they can be loaded from the shell environment, or from a file located in the root directory.
///
/// This allows us to keep sensitve settings out of the repository.
public struct EnvVars: Codable, Equatable {
  
  /// The current app environment.
  public var appEnv: AppEnv
  
  /// The MQTT host.
  public var host: String
  
  /// The MQTT port.
  public var port: String?
  
  /// The identifier to use when connecting to the MQTT broker.
  public var identifier: String
  
  /// The MQTT user name.
  public var userName: String?
  
  /// 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:
  ///   - appEnv: The current application environment
  ///   - host: The MQTT host.
  ///   - port: The MQTT port.
  ///   - identifier: The identifier to use when connecting to the MQTT broker.
  ///   - userName: The MQTT user name to connect to the broker with.
  ///   - password: The MQTT user password to connect to the broker with.
  public init(
    appEnv: AppEnv = .development,
    host: String = "127.0.0.1",
    port: String? = "1883",
    identifier: String = "dewPoint-controller",
    userName: String? = "mqtt_user",
    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
    self.port = port
    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.
  private enum CodingKeys: String, CodingKey {
    case appEnv = "APP_ENV"
    case host = "MQTT_HOST"
    case port = "MQTT_PORT"
    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.
  public enum AppEnv: String, Codable {
    case development
    case production
    case staging
    case testing
  }
}