import Foundation
import Logging
import OrderedCollections
import Routes

public extension RoomPressure.Request {

  static let pascalToIWCMultiplier = 0.004014
  static let targetVelocity = 400.0
  static let maxVelocity = 600.0
  static let minGrilleFreeArea = 0.7
  static let standardDuctSizes = OrderedSet([4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20])
  static let standardGrilleHeights = OrderedSet([4, 6, 8, 10, 12, 14, 20])
  static let standardGrilleSizes = [
    4: OrderedSet([8, 10, 12, 14]),
    6: OrderedSet([8, 10, 12, 14]),
    8: OrderedSet([10, 12, 14]),
    10: OrderedSet([10]),
    12: OrderedSet([12]),
    14: OrderedSet([14])
  ]

  // OrderedSet([
  //   (width: 8, height: 4),
  //   (width: 10, height: 4),
  //   (width: 12, height: 4),
  //   (width: 14, height: 4),
  //   (width: 8, height: 6),
  //   (width: 10, height: 6),
  //   (width: 12, height: 6),
  //   (width: 14, height: 6),
  //   (width: 10, height: 8),
  //   (width: 12, height: 8),
  //   (width: 14, height: 8),
  //   (width: 10, height: 10),
  //   (width: 12, height: 12),
  //   (width: 14, height: 14)
  // ])

  func respond(logger: Logger) async throws -> RoomPressure.Response {
    fatalError()
  }

  private func getStandardDuctSize(for calculatedSize: Int) -> Int {
    Self.standardDuctSizes.sorted()
      .first { $0 >= calculatedSize }
      ?? 20
  }

  private func getStandardGrilleSize(requiredArea: Double, selectedHeight: Int) throws -> (width: Int, height: Int) {
    guard let availableSizes = Self.standardGrilleSizes[selectedHeight] else {
      throw RoomPressureError.invalidPreferredHeight
    }

    if let width = availableSizes.first(where: {
      Double($0) * Double(selectedHeight) * Self.minGrilleFreeArea >= (requiredArea / Self.minGrilleFreeArea)
    }) {
      return (width, selectedHeight)
    }

    // If no width matches return largest for the selectedHeight.
    if let largestSize = availableSizes.last { return (largestSize, selectedHeight) }
    return (14, selectedHeight)
  }

  // Calculate door leakage area in sq. ft.
  private func calculateDoorLeakageArea(doorWidth: Double, doorHeight: Double, doorUndercut: Double) -> Double {
    let doorLeakageArea = (doorWidth * doorUndercut) / 144.0
    let doorPerimiterLeakage = ((2 * doorHeight + doorWidth) * 0.125) / 144.0
    return doorLeakageArea + doorPerimiterLeakage
  }

  enum RoomPressureError: Error {
    case invalidPreferredHeight
  }
}