import CoreModels

public enum HeatingBalancePoint {

  public static let description: String = """
  Calculate the heating balance point.
  """

  public enum Mode: String, CaseIterable, Codable, Equatable, Sendable, Hashable {
    case economic
    case thermal
  }

  public enum Request: Codable, Equatable, Sendable, Hashable {
    case economic(Economic)
    case thermal(Thermal)

    public struct Economic: Codable, Equatable, Sendable, Hashable {

      public let fuelType: FuelType
      public let fuelCostPerUnit: Double
      public let fuelAFUE: Double
      public let costPerKW: Double

      public init(
        fuelType: HeatingBalancePoint.FuelType,
        fuelCostPerUnit: Double,
        fuelAFUE: Double,
        costPerKW: Double
      ) {
        self.fuelType = fuelType
        self.fuelCostPerUnit = fuelCostPerUnit
        self.fuelAFUE = fuelAFUE
        self.costPerKW = costPerKW
      }
    }

    public struct Thermal: Codable, Equatable, Sendable, Hashable {

      public let systemSize: Double
      public let capacityAt47: Double?
      public let capacityAt17: Double?
      public let heatingDesignTemperature: Double?
      public let buildingHeatLoss: HeatingBalancePoint.HeatLoss
      public let climateZone: ClimateZone?

      public init(
        systemSize: Double,
        capacityAt47: Double? = nil,
        capacityAt17: Double? = nil,
        heatingDesignTemperature: Double? = nil,
        buildingHeatLoss: HeatingBalancePoint.HeatLoss,
        climateZone: ClimateZone? = nil
      ) {
        self.systemSize = systemSize
        self.capacityAt47 = capacityAt47
        self.capacityAt17 = capacityAt17
        self.heatingDesignTemperature = heatingDesignTemperature
        self.buildingHeatLoss = buildingHeatLoss
        self.climateZone = climateZone
      }
    }
  }

  public enum Response: Codable, Equatable, Sendable {
    case economic(Economic)
    case thermal(Thermal)

    public struct Economic: Codable, Equatable, Sendable {

      public let balancePointTemperature: Double
      public let fuelCostPerMMBTU: Double
      public let electricCostPerMMBTU: Double
      public let copAtBalancePoint: Double
      public let electricFuelRatio: Double

      public init(
        balancePointTemperature: Double,
        fuelCostPerMMBTU: Double,
        electricCostPerMMBTU: Double,
        copAtBalancePoint: Double,
        electricFuelRatio: Double
      ) {
        self.balancePointTemperature = balancePointTemperature
        self.fuelCostPerMMBTU = fuelCostPerMMBTU
        self.electricCostPerMMBTU = electricCostPerMMBTU
        self.copAtBalancePoint = copAtBalancePoint
        self.electricFuelRatio = electricFuelRatio
      }
    }

    public struct Thermal: Codable, Equatable, Sendable {

      public let capacityAt47: Double
      public let capacityAt17: Double
      public let balancePointTemperature: Double
      public let heatLoss: Double
      public let heatLossMode: HeatLoss.Mode
      public let heatingDesignTemperature: Double
      public let warnings: [String]

      public init(
        capacityAt47: Double,
        capacityAt17: Double,
        balancePointTemperature: Double,
        heatLoss: Double,
        heatLossMode: HeatLoss.Mode,
        heatingDesignTemperature: Double,
        warnings: [String]
      ) {
        self.capacityAt47 = capacityAt47
        self.capacityAt17 = capacityAt17
        self.balancePointTemperature = balancePointTemperature
        self.heatLoss = heatLoss
        self.heatLossMode = heatLossMode
        self.heatingDesignTemperature = heatingDesignTemperature
        self.warnings = warnings
      }
    }
  }

  public enum HeatLoss: Codable, Equatable, Sendable, Hashable {

    public enum Mode: String, CaseIterable, Codable, Equatable, Sendable, Hashable {
      case estimated
      case known
    }

    case known(btu: Double)
    case estimated(squareFeet: Double)

    public var mode: Mode {
      switch self {
      case .known: return .known
      case .estimated: return .estimated
      }
    }
  }

  public enum FuelType: String, CaseIterable, Codable, Equatable, Sendable, Hashable {
    case naturalGas
    case propane
    case oil

    public var label: String {
      switch self {
      case .propane, .oil: return "\(rawValue.capitalized)"
      case .naturalGas: return "Natural Gas"
      }
    }

    public var units: String {
      switch self {
      case .propane, .oil: return "gallons"
      case .naturalGas: return "therm"
      }
    }
  }
}

#if DEBUG
  public extension HeatingBalancePoint.Response {

    static func mock(mode: HeatingBalancePoint.Mode) -> Self {
      switch mode {
      case .economic:
        return .economic(.init(
          balancePointTemperature: -10.8,
          fuelCostPerMMBTU: 27.6,
          electricCostPerMMBTU: 38.1,
          copAtBalancePoint: 2.24,
          electricFuelRatio: 1.38
        ))
      case .thermal:
        return .thermal(.init(
          capacityAt47: 24600,
          capacityAt17: 15100,
          balancePointTemperature: 38.5,
          heatLoss: 49667,
          heatLossMode: .known,
          heatingDesignTemperature: 5,
          warnings: [
            "Design temperature is estimated based on climate zone."
          ]
        ))
      }
    }
  }
#endif