import Foundation

#warning("Make values non-optional")
#warning("Need to make air handler external static handle large filter pressure drops.")
#warning("Add an exterenal static pressure strategy for if the filter is built-in or external")
public enum EquipmentMeasurement: Equatable {
 
  case airHandler(AirHandler)
  case furnaceAndCoil(FurnaceAndCoil)
  
  public var equipmentType: EquipmentType {
    switch self {
    case .airHandler:
      return .airHandler
    case .furnaceAndCoil:
      return .furnaceAndCoil
    }
  }
  
  public var externalStaticPressure: Double {
    switch self {
    case let .airHandler(airHandler):
      return airHandler.externalStaticPressure
    case let .furnaceAndCoil(furnaceAndCoil):
      return furnaceAndCoil.externalStaticPressure
    }
  }
  
  public struct AirHandler: Equatable {

    @Positive
    public var airflow: Double?

    @Positive
    public var returnPlenumPressure: Double?
    
    @Positive
    public var postFilterPressure: Double?
    
    @Positive
    public var postCoilPressure: Double?
    
    @Positive
    public var supplyPlenumPressure: Double?
    
    public init(
      airflow: Double? = nil,
      returnPlenumPressure: Double? = nil,
      postFilterPressure: Double? = nil,
      postCoilPressure: Double? = nil,
      supplyPlenumPressure: Double? = nil
    ) {
      self.airflow = airflow
      self.returnPlenumPressure = returnPlenumPressure
      self.postFilterPressure = postFilterPressure
      self.postCoilPressure = postCoilPressure
      self.supplyPlenumPressure = supplyPlenumPressure
    }
    
    public var externalStaticPressure: Double {
      var postFilterAdder = 0.0
      if let postFilterPressure = $postFilterPressure.positiveValue,
         postFilterPressure > 0.1 
      {
        postFilterAdder = postFilterPressure - 0.1
      }
      return ($returnPlenumPressure.positiveValue ?? 0)
      + postFilterAdder
      + ($supplyPlenumPressure.positiveValue ?? 0)
    }
  }
  
  public struct FurnaceAndCoil: Equatable {

    @Positive
    public var airflow: Double?

    @Positive
    public var returnPlenumPressure: Double?
    
    @Positive
    public var postFilterPressure: Double?
    
    @Positive
    public var preCoilPressure: Double?
    
    @Positive
    public var supplyPlenumPressure: Double?
    
    public init(
      airflow: Double? = nil,
      returnPlenumPressure: Double? = nil,
      postFilterPressure: Double? = nil,
      preCoilPressure: Double? = nil,
      supplyPlenumPressure: Double? = nil
    ) {
      self.airflow = airflow
      self.returnPlenumPressure = returnPlenumPressure
      self.postFilterPressure = postFilterPressure
      self.preCoilPressure = preCoilPressure
      self.supplyPlenumPressure = supplyPlenumPressure
    }
    
    public var externalStaticPressure: Double {
      ($postFilterPressure.positiveValue ?? 0) + ($preCoilPressure.positiveValue ?? 0)
    }
  }
}

//extension EquipmentMeasurement.AirHandler {
//  
//  public enum Key: String, Equatable, CaseIterable {
//    case returnPlenumPressure
//    case postFilterPressure
//    case postCoilPressure
//    case supplyPlenumPressure
//    case airflow
//  }
//}
//
//extension EquipmentMeasurement.FurnaceAndCoil {
//  
//  public enum Key: String, Equatable, CaseIterable {
//    case returnPlenumPressure
//    case postFilterPressure
//    case preCoilPressure
//    case supplyPlenumPressure
//    case airflow
//  }
//}

#if DEBUG
extension EquipmentMeasurement {
  public static func mock(type equipmentType: EquipmentType) -> Self {
    switch equipmentType {
    case .airHandler:
      return .airHandler(.init(
        airflow: 1200,
        returnPlenumPressure: 0.3,
        postFilterPressure: 0.6,
        postCoilPressure: 0.9,
        supplyPlenumPressure: 0.2
      ))

    case .furnaceAndCoil:
      return .furnaceAndCoil(.init(
        airflow: 1200,
        returnPlenumPressure: 0.3,
        postFilterPressure: 0.6,
        preCoilPressure: 0.4,
        supplyPlenumPressure: 0.1
      ))
    }
  }
}
#endif