import Foundation

public struct BudgetedPercentEnvelope: Equatable {
  
  public var coilBudget: Percentage
  public var filterBudget: Percentage
  public var returnPlenumBudget: Percentage
  public var supplyPlenumBudget: Percentage
  
  public var preCoilBudget: Percentage {
    coilBudget + supplyPlenumBudget
  }
  
  public init(
    coilBudget: Percentage,
    filterBudget: Percentage,
    returnPlenumBudget: Percentage,
    supplyPlenumBudget: Percentage
  ) {
    self.coilBudget = coilBudget
    self.filterBudget = filterBudget
    self.returnPlenumBudget = returnPlenumBudget
    self.supplyPlenumBudget = supplyPlenumBudget
  }

  public var total: Percentage {
    coilBudget + filterBudget + supplyPlenumBudget + returnPlenumBudget
  }

  public init(equipmentType: EquipmentType, fanType: FanType) {
    switch equipmentType {
    case .furnaceAndCoil:
      switch fanType {
      case .constantSpeed:
        self.init(
          coilBudget: 40%,
          filterBudget: 20%,
          returnPlenumBudget: 20%,
          supplyPlenumBudget: 20%
        )
      case .variableSpeed:
        self.init(
          coilBudget: 30%,
          filterBudget: 40%,
          returnPlenumBudget: 15%,
          supplyPlenumBudget: 15%
        )
      }
    case .airHandler:
      self.init(
        coilBudget: .zero,
        filterBudget: 50%,
        returnPlenumBudget: 25%,
        supplyPlenumBudget: 25%
      )
    }
  }
}