feat: Adds thermal balance point, still need to implement economic balance point.

Package.swift

@@ -9,7 +9,6 @@ let package = Package(
   products: [
     .executable(name: "App", targets: ["App"]),
     .library(name: "ApiController", targets: ["ApiController"]),
-    .library(name: "ClimateZoneClient", targets: ["ClimateZoneClient"]),
     .library(name: "CoreModels", targets: ["CoreModels"]),
     .library(name: "LocationClient", targets: ["LocationClient"]),
     .library(name: "Routes", targets: ["Routes"]),
@@ -62,22 +61,6 @@ let package = Package(
       ],
       swiftSettings: swiftSettings
     ),
-    .target(
-      name: "LocationClient",
-      dependencies: [
-        .product(name: "Dependencies", package: "swift-dependencies"),
-        .product(name: "DependenciesMacros", package: "swift-dependencies")
-      ],
-      swiftSettings: swiftSettings
-    ),
-    .target(
-      name: "ClimateZoneClient",
-      dependencies: [
-        .product(name: "Dependencies", package: "swift-dependencies"),
-        .product(name: "DependenciesMacros", package: "swift-dependencies")
-      ],
-      swiftSettings: swiftSettings
-    ),
     .target(
       name: "CoreModels",
       dependencies: [],
@@ -94,6 +77,7 @@ let package = Package(
     .target(
       name: "LocationClient",
       dependencies: [
+        "CoreModels",
         .product(name: "Dependencies", package: "swift-dependencies"),
         .product(name: "DependenciesMacros", package: "swift-dependencies")
       ],

Sources/ApiController/Extensions/HeatingBalancePoint.swift

@@ -0,0 +1,158 @@
+import CoreModels
+import Foundation
+import Logging
+import Routes
+
+public extension HeatingBalancePoint.Request {
+
+  func respond(logger: Logger) async throws -> HeatingBalancePoint.Response {
+    switch self {
+    case let .thermal(request):
+      logger.debug("Calculating thermal balance point: \(request)")
+      return try await request.respond(logger: logger)
+    }
+  }
+}
+
+private extension HeatingBalancePoint.Request.Thermal {
+
+  static let heatPumpDeratingFactor = 0.014
+
+  func respond(logger: Logger) async throws -> HeatingBalancePoint.Response {
+    try validate()
+    let (at47, at17) = getCapacities()
+    let heatingDesignTemperature = getHeatingDesignTemperature()
+    let buildingHeatLoss = getBuildingHeatLoss(designTemperature: heatingDesignTemperature)
+
+    let balancePoint = await thermalBalancePoint(
+      heatLoss: buildingHeatLoss,
+      at47: at47,
+      at17: at17,
+      designTemperature: heatingDesignTemperature
+    )
+
+    let warnings = getWarnings()
+
+    return .thermal(.init(
+      capacityAt47: at47,
+      capacityAt17: at17,
+      balancePointTemperature: balancePoint,
+      heatLoss: buildingHeatLoss,
+      heatLossMode: self.buildingHeatLoss.mode,
+      heatingDesignTemperature: heatingDesignTemperature,
+      warnings: warnings
+    ))
+  }
+
+  func getWarnings() -> [String] {
+    var warnings = [String]()
+    if capacityAt17 == nil || capacityAt47 == nil {
+      warnings.append(
+        "Heat pump capacities are estimated based on system size - include actual capacities for higher accuracy."
+      )
+    }
+    if case .estimated = buildingHeatLoss {
+      warnings.append(
+        "Building heat loss is estimated based on climate zone - include actual heat loss for higher accuracy"
+      )
+    }
+    if heatingDesignTemperature == nil {
+      warnings.append(
+        """
+        Heating outdoor design temperature is based on average for climate zone - include outdoor design temperature
+        for higher accuracy.
+        """
+      )
+    }
+
+    return warnings
+  }
+
+  func getBuildingHeatLoss(designTemperature: Double) -> Double {
+    switch buildingHeatLoss {
+    case let .known(btu: btu): return btu
+    case let .estimated(squareFeet: squareFeet):
+      return squareFeet * climateZone!.averageHeatLossPerSquareFoot * (70 - designTemperature)
+    }
+  }
+
+  func getCapacities() -> (at47: Double, at17: Double) {
+    let at47 = capacityAt47 ?? systemSize * 12000
+    let at17 = capacityAt17 ?? at47 * (1 - Self.heatPumpDeratingFactor * (47 - 17))
+    return (at47, at17)
+  }
+
+  func getHeatingDesignTemperature() -> Double {
+    guard let heatingDesignTemperature else {
+      return climateZone!.averageHeatingDesignTemperature
+    }
+    return heatingDesignTemperature
+  }
+
+  func validate() throws {
+    guard systemSize > 0 else {
+      throw ValidationError(message: "System size should be greater than 0.")
+    }
+    switch buildingHeatLoss {
+    case let .known(btu: btu):
+      guard btu > 0 else {
+        throw ValidationError(message: "Building heat loss btu's should be greater than 0.")
+      }
+    case let .estimated(squareFeet: squareFeet):
+      guard squareFeet > 0 else {
+        throw ValidationError(message: "Building squareFeet should be greater than 0.")
+      }
+      guard climateZone != nil else {
+        throw ValidationError(message: "Climate zone is required when estimating heat loss.")
+      }
+    }
+    if let capacityAt47 {
+      guard capacityAt47 > 0 else {
+        throw ValidationError(message: "Heat pump capacity @ 47 should be greater than 0.")
+      }
+    }
+    if let capacityAt17 {
+      guard capacityAt17 > 0 else {
+        throw ValidationError(message: "Heat pump capacity @ 17 should be greater than 0.")
+      }
+    }
+  }
+}
+
+extension ClimateZone {
+
+  var averageHeatLossPerSquareFoot: Double {
+    switch self {
+    case .one: return 0.08
+    case .two: return 0.1
+    case .three: return 0.125
+    case .four: return 0.15
+    case .five: return 0.19
+    case .six: return 0.25
+    case .seven: return 0.3
+    }
+  }
+
+  var averageHeatingDesignTemperature: Double {
+    switch self {
+    case .one: return 45
+    case .two: return 35
+    case .three: return 27
+    case .four: return 17
+    case .five: return 7
+    case .six: return -5
+    case .seven: return -15
+    }
+  }
+}
+
+private func thermalBalancePoint(
+  heatLoss: Double,
+  at47: Double,
+  at17: Double,
+  designTemperature: Double
+) async -> Double {
+  (30.0 * (((designTemperature - 65.0) * at47) + (65.0 * heatLoss))
+    - ((designTemperature - 65.0) * (at47 - at17) * 47.0))
+    / ((30.0 * heatLoss) - ((designTemperature - 65.0) * (at47 - at17)))
+}

Sources/CoreModels/ClimateZone.swift

@@ -1,6 +1,16 @@
 import Foundation
 
-public enum ClimateZone {
+public enum ClimateZone: String, CaseIterable, Codable, Equatable, Sendable {
+
+  case one = "CZ1"
+  case two = "CZ2"
+  case three = "CZ3"
+  case four = "CZ4"
+  case five = "CZ5"
+  case six = "CZ6"
+  case seven = "CZ7"
+
+  public var label: String { rawValue }
 
   public enum ZoneType: String, CaseIterable, Codable, Equatable, Sendable {
     // NOTE: Keep in this order.
@@ -35,33 +45,33 @@ public enum ClimateZone {
     public var label: String {
       return "\(self == .hotHumid ? "Hot Humid" : rawValue.capitalized) (\(zoneIdentifiers.joined(separator: ", ")))"
     }
+  }
 
-    /// Represents climate zone identifiers.
-    public enum ZoneIdentifier: String, CaseIterable, Codable, Equatable, Sendable {
-      // A zones (hotHumid)
-      case oneA = "1A"
-      case twoA = "2A"
-      // A zones (moist)
-      case threeA = "3A"
-      case fourA = "4A"
-      case fiveA = "5A"
-      case sixA = "6A"
-      case sevenA = "7A"
+  /// Represents climate zone identifiers.
+  public enum ZoneIdentifier: String, CaseIterable, Codable, Equatable, Sendable {
+    // A zones (hotHumid)
+    case oneA = "1A"
+    case twoA = "2A"
+    // A zones (moist)
+    case threeA = "3A"
+    case fourA = "4A"
+    case fiveA = "5A"
+    case sixA = "6A"
+    case sevenA = "7A"
 
-      // B zones (dry)
-      case twoB = "2B"
-      case threeB = "3B"
-      case fourB = "4B"
-      case fiveB = "5B"
-      case sixB = "6B"
-      case sevenB = "7B"
+    // B zones (dry)
+    case twoB = "2B"
+    case threeB = "3B"
+    case fourB = "4B"
+    case fiveB = "5B"
+    case sixB = "6B"
+    case sevenB = "7B"
 
-      // C zones (marine)
-      case threeC = "3C"
-      case fourC = "4C"
+    // C zones (marine)
+    case threeC = "3C"
+    case fourC = "4C"
 
-      public var label: String { rawValue }
+    public var label: String { rawValue }
 
-    }
   }
 }

Sources/LocationClient/LocationClient.swift

@@ -1,3 +1,4 @@
+@_exported import CoreModels
 import Dependencies
 import DependenciesMacros
 import Foundation
@@ -11,56 +12,135 @@ public extension DependencyValues {
 
 @DependencyClient
 public struct LocationClient: Sendable {
-  public var search: @Sendable (Int) async throws -> [Response]
 
-  // TODO: Add ClimateZone.ZoneIdentifier??
-  public struct Response: Codable, Equatable, Sendable {
+  /// Estimate the climate zone by the heating design temperature and
+  /// the state code (ex. "OH").
+  public var estimatedClimateZone:
+    @Sendable (_ heatingTemperature: Double, _ stateCode: String) async throws -> ClimateZone
 
-    public let city: String
-    public let latitude: String
-    public let longitude: String
-    public let zipCode: String
-    public let state: String
-    public let stateCode: String
-    public let county: String
+  /// Estimate the design temperatures based on location's coordinates.
+  public var estimatedDesignTemperatures: @Sendable (Coordinates) async throws -> DesignTemperatures
 
-    public init(
-      city: String,
-      latitude: String,
-      longitude: String,
-      zipCode: String,
-      state: String,
-      stateCode: String,
-      county: String
-    ) {
-      self.city = city
-      self.latitude = latitude
-      self.longitude = longitude
-      self.zipCode = zipCode
-      self.state = state
-      self.stateCode = stateCode
-      self.county = county
-    }
+  /// Get location details from a zip code.
+  public var search: @Sendable (_ zipCode: Int) async throws -> [Location]
 
-    private enum CodingKeys: String, CodingKey {
-      case city
-      case latitude
-      case longitude
-      case zipCode = "postal_code"
-      case state
-      case stateCode = "state_code"
-      case county = "province"
-    }
+  public func estimateDesignTemperaturesAndClimateZone(
+    coordinates: Coordinates,
+    stateCode: String
+  ) async throws -> (DesignTemperatures, ClimateZone) {
+    let designTemperatures = try await estimatedDesignTemperatures(coordinates)
+    let climateZone = try await estimatedClimateZone(
+      heatingTemperature: designTemperatures.heating,
+      stateCode: stateCode
+    )
+    return (designTemperatures, climateZone)
   }
+
 }
 
+struct DecodingError: Error {}
+
 extension LocationClient: TestDependencyKey {
   public static let testValue: LocationClient = Self()
 }
 
+// Intermediate response returned from 'https://app.zipcodebase.com'
+private struct IntermediateResponse: Codable, Equatable, Sendable {
+
+  let city: String
+  let latitude: String
+  let longitude: String
+  let zipCode: String
+  let state: String
+  let stateCode: String
+  let county: String
+
+  func toLocation() throws -> Location {
+    guard let longitude = Double(longitude), let latitude = Double(latitude) else {
+      throw DecodingError()
+    }
+    return .init(
+      city: city,
+      state: state,
+      stateCode: stateCode,
+      zipCode: zipCode,
+      county: county,
+      coordinates: .init(latitude: latitude, longitude: longitude)
+    )
+  }
+
+  private enum CodingKeys: String, CodingKey {
+    case city
+    case latitude
+    case longitude
+    case zipCode = "postal_code"
+    case state
+    case stateCode = "state_code"
+    case county = "province"
+  }
+}
+
+// TODO: Need to add climate zone 7 (-17).
+private func estimatedHeatingTemperature(_ coordinates: Coordinates) -> Double {
+  let latitude = coordinates.latitude
+  let longitude = coordinates.longitude
+
+  // Gulf coast region
+  if latitude < 31, longitude > -95 && longitude < -89 {
+    return 35
+  }
+
+  // Florida
+  if latitude < 31, longitude > -87.5 && longitude < -80 {
+    return 40
+  }
+
+  let absLat = abs(latitude)
+  if absLat < 30 { return 35 }
+  if absLat < 33 { return 30 }
+  if absLat < 36 { return 25 }
+  if absLat < 40 { return 15 }
+  if absLat < 45 { return 5 }
+  return 0
+}
+
+// TODO: Need to add climate zone 7 (89).
+private func estimatedCoolingTemperature(_ coordinates: Coordinates) -> Double {
+  let latitude = coordinates.latitude
+  let longitude = coordinates.longitude
+
+  // Gulf coast and Florida
+  if latitude < 31, longitude > -95 && longitude < -80 {
+    return 95
+  }
+
+  let absLat = abs(latitude)
+  if absLat < 30 { return 95 }
+  if absLat < 33 { return 92 }
+  if absLat < 36 { return 90 }
+  if absLat < 40 { return 90 }
+  if absLat < 45 { return 88 }
+  return 85
+}
+
+// TODO: Need to add climate zone 7.
+private func determineClimateZone(heatingTemperature: Double, stateCode: String) -> ClimateZone {
+  let hotHumidStates = ["FL", "LA", "TX", "MS", "AL", "GA", "SC"]
+  if hotHumidStates.contains(stateCode.uppercased()) {
+    return .two
+  }
+
+  if heatingTemperature >= 45 { return .one }
+  if heatingTemperature >= 35 { return .two }
+  if heatingTemperature >= 25 { return .three }
+  if heatingTemperature >= 15 { return .four }
+  if heatingTemperature >= 5 { return .five }
+  return .six
+}
+
 #if DEBUG
 
-  public extension LocationClient.Response {
+  extension IntermediateResponse {
     static let mock = Self(
       city: "Monroe",
       latitude: "39.4413000",

Sources/Routes/Models/HeatingBalancePoint.swift

@@ -0,0 +1,118 @@
+import CoreModels
+
+public enum HeatingBalancePoint {
+
+  public static let description: String = """
+  Calculate the heating balance point.
+  """
+
+  public enum Mode: String, CaseIterable, Codable, Equatable, Sendable {
+    case economic
+    case thermal
+  }
+
+  public enum Request: Codable, Equatable, Sendable {
+    case thermal(Thermal)
+
+    public struct Thermal: Codable, Equatable, Sendable {
+
+      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 thermal(Thermal)
+
+    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 {
+
+    public enum Mode: String, CaseIterable, Codable, Equatable, Sendable {
+      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
+      }
+    }
+  }
+}
+
+#if DEBUG
+  public extension HeatingBalancePoint.Response {
+
+    static func mock(mode: HeatingBalancePoint.Mode) -> Self {
+      switch mode {
+      case .economic:
+        fatalError()
+      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

Sources/Routes/SiteRoutes.swift

@@ -4,6 +4,7 @@ import Foundation
 import PsychrometricClient
 @preconcurrency import URLRouting
 
+// swiftlint:disable type_body_length
 public enum SiteRoute: Equatable, Sendable {
 
   case api(Api)
@@ -101,6 +102,7 @@ public extension SiteRoute {
     case capacitor(Capacitor)
     case dehumidifierSize(DehumidifierSize)
     case filterPressureDrop(FilterPressureDrop)
+    case heatingBalancePoint(HeatingBalancePoint)
     case hvacSystemPerformance(HVACSystemPerformance)
     case moldRisk(MoldRisk)
     case roomPressure(RoomPressure)
@@ -121,6 +123,9 @@ public extension SiteRoute {
       Route(.case(Self.filterPressureDrop)) {
         FilterPressureDrop.router
       }
+      Route(.case(Self.heatingBalancePoint)) {
+        HeatingBalancePoint.router
+      }
       Route(.case(Self.hvacSystemPerformance)) {
         HVACSystemPerformance.router
       }
@@ -280,6 +285,60 @@ public extension SiteRoute {
       }
     }
 
+    public enum HeatingBalancePoint: Equatable, Sendable {
+      case index(
+        mode: Routes.HeatingBalancePoint.Mode? = nil,
+        heatLossMode: Routes.HeatingBalancePoint.HeatLoss.Mode? = nil
+      )
+      case heatLossFields(mode: Routes.HeatingBalancePoint.HeatLoss.Mode)
+      case submit(Routes.HeatingBalancePoint.Request)
+
+      public static var index: Self { index() }
+
+      static let rootPath = "balance-point"
+
+      public static let router = OneOf {
+        Route(.case(Self.index)) {
+          Path { rootPath }
+          Method.get
+          Query {
+            Optionally { Field("mode") { Routes.HeatingBalancePoint.Mode.parser() } }
+            Optionally { Field("heatLossMode") { Routes.HeatingBalancePoint.HeatLoss.Mode.parser() } }
+          }
+        }
+        Route(.case(Self.heatLossFields)) {
+          Path { rootPath; "heat-loss" }
+          Method.get
+          Query {
+            Field("mode") { Routes.HeatingBalancePoint.HeatLoss.Mode.parser() }
+          }
+        }
+        Route(.case(Self.submit)) {
+          Path { rootPath }
+          Method.post
+          Body {
+            OneOf {
+              FormData {
+                Field("systemSize") { Double.parser() }
+                Optionally { Field("capacityAt47") { Double.parser() } }
+                Optionally { Field("capacityAt17") { Double.parser() } }
+                Optionally { Field("heatingDesignTemperature") { Double.parser() } }
+                OneOf {
+                  Field("knownHeatLoss") { Double.parser() }
+                    .map(.case(Routes.HeatingBalancePoint.HeatLoss.known))
+                  Field("simplifiedHeatLoss") { Double.parser() }
+                    .map(.case(Routes.HeatingBalancePoint.HeatLoss.estimated))
+                }
+                Optionally { Field("climateZone") { ClimateZone.parser() } }
+              }
+              .map(.memberwise(Routes.HeatingBalancePoint.Request.Thermal.init))
+              .map(.case(Routes.HeatingBalancePoint.Request.thermal))
+            }
+          }
+        }
+      }
+    }
+
     public enum HVACSystemPerformance: Equatable, Sendable {
       case index
       case submit(Routes.HVACSystemPerformance.Request)
@@ -392,3 +451,5 @@ public extension SiteRoute {
     }
   }
 }
+
+// swiftlint:enable type_body_length

Sources/Routes/String+double.swift

@@ -1,17 +1,10 @@
 import Foundation
 
-private let numberFormatter: NumberFormatter = {
-  let formatter = NumberFormatter()
-  formatter.numberStyle = .decimal
-  formatter.maximumFractionDigits = 2
-  return formatter
-}()
-
 public extension String.StringInterpolation {
   mutating func appendInterpolation(double: Double, fractionDigits: Int = 2) {
     let formatter = NumberFormatter()
     formatter.numberStyle = .decimal
     formatter.maximumFractionDigits = fractionDigits
-    appendInterpolation(numberFormatter.string(from: NSNumber(value: double))!)
+    appendInterpolation(formatter.string(from: NSNumber(value: double))!)
   }
 }

Sources/Styleguide/Buttons.swift

@@ -110,17 +110,17 @@ public struct Toggle: HTML {
       switch isOn {
       case true:
         SecondaryButton(label: onLabel)
-          .attributes(.class("rounded-s-lg"), .disabled)
+          .attributes(.class("rounded-s-lg"), .disabled, .type(.button))
 
         PrimaryButton(label: offLabel)
-          .attributes(contentsOf: offAttributes + [.class("rounded-e-lg")])
+          .attributes(contentsOf: offAttributes + [.class("rounded-e-lg"), .type(.button)])
 
       case false:
         PrimaryButton(label: onLabel)
-          .attributes(contentsOf: onAttributes + [.class("rounded-s-lg")])
+          .attributes(contentsOf: onAttributes + [.class("rounded-s-lg"), .type(.button)])
 
         SecondaryButton(label: offLabel)
-          .attributes(.class("rounded-e-lg"), .disabled)
+          .attributes(.class("rounded-e-lg"), .disabled, .type(.button))
       }
     }
   }

Sources/Styleguide/SVG.swift

@@ -52,6 +52,7 @@ public enum SVGType: Sendable, CaseIterable {
   case leftRightArrow
   case menu
   case ruler
+  case scale
   case thermometer
   case thermometerSun
   case wind
@@ -69,6 +70,7 @@ public enum SVGType: Sendable, CaseIterable {
     case .leftRightArrow: return leftRightArrowSvg(size: size)
     case .menu: return menuSvg(size: size)
     case .ruler: return rulerSvg(size: size)
+    case .scale: return scaleSvg(size: size)
     case .thermometer: return thermometerSvg(size: size)
     case .thermometerSun: return thermometerSunSvg(size: size)
     case .wind: return windSvg(size: size)
@@ -82,6 +84,17 @@ public enum SVGType: Sendable, CaseIterable {
 
 // swiftlint:disable line_length
 
+private func scaleSvg(size: SVGSize) -> HTMLRaw {
+  HTMLRaw("""
+  <svg xmlns="http://www.w3.org/2000/svg" width="\(size.width)" height="\(size.height)" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-scale">
+  <path d="m16 16 3-8 3 8c-.87.65-1.92 1-3 1s-2.13-.35-3-1Z"/>
+  <path d="m2 16 3-8 3 8c-.87.65-1.92 1-3 1s-2.13-.35-3-1Z"/>
+  <path d="M7 21h10"/><path d="M12 3v18"/>
+  <path d="M3 7h2c2 0 5-1 7-2 2 1 5 2 7 2h2"/>
+  </svg>
+  """)
+}
+
 private func checkCircleSvg(size: SVGSize) -> HTMLRaw {
   HTMLRaw("""
   <svg xmlns="http://www.w3.org/2000/svg" width="\(size.width)" height="\(size.height)" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-circle-check-big">

Sources/Styleguide/WarningBox.swift

@@ -26,7 +26,7 @@ public struct WarningBox<Header: HTML>: HTML, Sendable {
     div(.id("warnings")) {
       if warnings.count > 0 {
         header(warnings)
-        ul(.class("list-disc mx-10")) {
+        ul(.class("list-disc mx-10 mt-4")) {
           for warning in warnings {
             li { warning }
           }
@@ -52,7 +52,7 @@ public extension WarningBox where Header == HTMLElement<HTMLTag.span, HTMLText>
     self.init(
       warnings: warnings,
       header: { warnings in
-        span(.class("font-semibold mb-4 border-b")) { "Warning\(warnings.count > 1 ? "s:" : ":")" }
+        span(.class("font-semibold mb-4 border-b border-amber-500")) { "Warning\(warnings.count > 1 ? "s:" : ":")" }
       }
     )
   }

Sources/ViewController/HomePage.swift

@@ -49,6 +49,12 @@ struct HomePage: HTML, Sendable {
         svg: .funnel,
         route: .filterPressureDrop(.index)
       )
+      group(
+        label: "Heating Balance Point",
+        description: HeatingBalancePoint.description,
+        svg: .scale,
+        route: .heatingBalancePoint(.index)
+      )
     }
   }
 

Sources/ViewController/Live.swift

@@ -109,6 +109,21 @@ extension ViewController: DependencyKey {
           return FilterPressureDropResponse(response: response)
         }
 
+      case let .heatingBalancePoint(route):
+        switch route {
+        case let .index(mode: mode, heatLossMode: heatLossMode):
+          return request.respond(HeatingBalancePointForm(
+            mode: mode,
+            heatLossMode: heatLossMode,
+            response: nil
+          ))
+        case let .heatLossFields(mode: mode):
+          return HeatingBalancePointForm.HeatLossFields(mode: mode)
+        case let .submit(request):
+          let response = try await request.respond(logger: logger)
+          return HeatingBalancePointResponse(response: response)
+        }
+
       case let .hvacSystemPerformance(route):
         switch route {
         case .index:

Sources/ViewController/Views/HeatingBalancePoint.swift

@@ -0,0 +1,251 @@
+import Elementary
+import ElementaryHTMX
+import Routes
+import Styleguide
+
+struct HeatingBalancePointForm: HTML, Sendable {
+  let mode: HeatingBalancePoint.Mode
+  let heatLossMode: HeatingBalancePoint.HeatLoss.Mode
+  let response: HeatingBalancePoint.Response?
+
+  init(
+    mode: HeatingBalancePoint.Mode?,
+    heatLossMode: HeatingBalancePoint.HeatLoss.Mode? = nil,
+    response: HeatingBalancePoint.Response? = nil
+  ) {
+    self.mode = mode ?? .thermal
+    self.heatLossMode = heatLossMode ?? .estimated
+    self.response = response
+  }
+
+  var content: some HTML {
+    div(.class("flex flex-wrap justify-between")) {
+      FormHeader(label: "Balance Point - \(mode.label)", svg: .scale)
+
+      Toggle(
+        isOn: mode == .thermal,
+        onLabel: HeatingBalancePoint.Mode.thermal.label,
+        onAttributes: .hxDefaults(get: .heatingBalancePoint(.index(mode: .thermal, heatLossMode: heatLossMode))),
+        offLabel: HeatingBalancePoint.Mode.economic.label,
+        offAttributes: .hxDefaults(get: .heatingBalancePoint(.index(mode: .economic, heatLossMode: heatLossMode)))
+      )
+      .attributes(.class("mb-6"))
+    }
+
+    form(
+      .hx.post(route: .heatingBalancePoint(.index)),
+      .hx.target("#result")
+    ) {
+      div(.class("space-y-6")) {
+        switch mode {
+        case .thermal:
+          ThermalFields(heatLossMode: heatLossMode)
+        case .economic:
+          div {
+            // FIX:
+            WarningBox("This is still under development and may not be fully functional.")
+              .attributes(.class("mb-6"))
+          }
+        }
+
+        div {
+          SubmitButton(label: "Calculate Balance Point")
+        }
+      }
+    }
+
+    div(.id("result")) {
+      if let response {
+        HeatingBalancePointResponse(response: response)
+      }
+    }
+  }
+
+  struct ThermalFields: HTML, Sendable {
+    let heatLossMode: HeatingBalancePoint.HeatLoss.Mode
+
+    var content: some HTML {
+      LabeledContent(label: "System Size (Tons)") {
+        Input(id: "systemSize", placeholder: "System size")
+          .attributes(.type(.number), .min("1"), .step("0.5"), .autofocus, .required)
+      }
+      div {
+        div(.class("mb-4")) {
+          h4(.class("text-lg font-bold")) { "Capacities" }
+          p(.class("text-xs text-blue-500")) {
+            "Entering known capacities gives better results, otherwise capacities will be estimated."
+          }
+        }
+        div(.class("grid grid-cols-1 lg:grid-cols-2 gap-4")) {
+          LabeledContent(label: "Capacity @ 47° (BTU/h)") {
+            Input(id: "capacityAt47", placeholder: "Capacity @ 47° (optional)")
+              .attributes(.type(.number), .min("1"), .step("0.5"))
+          }
+          LabeledContent(label: "Capacity @ 17° (BTU/h)") {
+            Input(id: "capacityAt17", placeholder: "Capacity @ 17° (optional)")
+              .attributes(.type(.number), .min("1"), .step("0.5"))
+          }
+        }
+      }
+      HeatLossFields(mode: heatLossMode)
+    }
+  }
+
+  struct HeatLossFields: HTML, Sendable {
+    let mode: HeatingBalancePoint.HeatLoss.Mode
+
+    var content: some HTML {
+      div(.id("heatLossFields")) {
+        div(.class("flex flex-wrap justify-between")) {
+          h4(.class("text-lg font-bold")) { "Heat Loss - \(mode.label)" }
+          Toggle(
+            isOn: mode == .estimated,
+            onLabel: HeatingBalancePoint.HeatLoss.Mode.estimated.label,
+            onAttributes: [
+              .hx.get(route: .heatingBalancePoint(.heatLossFields(mode: .estimated))),
+              .hx.target("#heatLossFields")
+            ],
+            offLabel: HeatingBalancePoint.HeatLoss.Mode.known.label,
+            offAttributes: [
+              .hx.get(route: .heatingBalancePoint(.heatLossFields(mode: .known))),
+              .hx.target("#heatLossFields")
+            ]
+          )
+          .attributes(.class("mb-6"))
+        }
+        switch mode {
+        case .known:
+          knownFields
+        case .estimated:
+          simplifiedFields
+        }
+      }
+    }
+
+    private var simplifiedFields: some HTML {
+      div(.class("grid grid-cols-1 lg:grid-cols-3 gap-4")) {
+        LabeledContent(label: "Building Size (ft²)") {
+          Input(id: "simplifiedHeatLoss", placeholder: "Square feet")
+            .attributes(.type(.number), .min("1"), .step("0.5"), .required)
+        }
+        div {
+          InputLabel(for: "climateZone") { "Climate Zone" }
+          Select(for: ClimateZone.self, id: "climateZone") { $0.rawValue }
+        }
+        LabeledContent(label: "Outdoor Design Temperature (°F)") {
+          Input(id: "heatingDesignTemperature", placeholder: "Design temperature (optional)")
+            .attributes(.type(.number), .step("0.5"))
+        }
+      }
+    }
+
+    private var knownFields: some HTML {
+      div(.class("grid grid-cols-1 lg:grid-cols-2 gap-4")) {
+        LabeledContent(label: "Heat Loss (BTU/h)") {
+          Input(id: "knownHeatLoss", placeholder: "Heat loss")
+            .attributes(.type(.number), .min("1"), .step("0.5"), .required)
+        }
+        LabeledContent(label: "Outdoor Design Temperature (°F)") {
+          Input(id: "heatingDesignTemperature", placeholder: "Design temperature")
+            .attributes(.type(.number), .step("0.5"), .required)
+        }
+      }
+    }
+
+  }
+
+}
+
+struct HeatingBalancePointResponse: HTML, Sendable {
+
+  let response: HeatingBalancePoint.Response
+
+  var content: some HTML {
+    ResultContainer(reset: .heatingBalancePoint(.index(mode: response.mode, heatLossMode: nil))) {
+      div(
+        .class("""
+        w-full rounded-xl shadow-xl bg-blue-100 text-blue-600 border border-blue-600 py-4
+        """)
+      ) {
+        div(.class("flex")) {
+          SVG(.scale, color: "text-blue-600")
+            .attributes(.class("px-4"))
+          p(.class("font-medium")) {
+            "\(response.mode.label) Balance Point"
+          }
+        }
+        switch response {
+        case let .thermal(result):
+          thermalResult(result)
+        }
+      }
+
+      WarningBox(warnings: response.warnings)
+    }
+  }
+
+  func thermalResult(_ result: HeatingBalancePoint.Response.Thermal) -> some HTML {
+    div {
+      VerticalGroup(
+        label: "Balance Point",
+        value: "\(double: result.balancePointTemperature, fractionDigits: 1)",
+        valueLabel: "°F"
+      )
+      .attributes(.class("mb-8"))
+
+      div(.class("grid grid-cols-2 space-y-6")) {
+        div {
+          VerticalGroup(
+            label: "Heat Loss - \(result.heatLossMode.label)",
+            value: "\(double: result.heatLoss, fractionDigits: 0)",
+            valueLabel: "BTU/h"
+          )
+        }
+        div {
+          VerticalGroup(
+            label: "Heating Design Temperature",
+            value: "\(double: result.heatingDesignTemperature, fractionDigits: 0)",
+            valueLabel: "°F"
+          )
+        }
+        div {
+          VerticalGroup(
+            label: "Capacity @ 47°",
+            value: "\(double: result.capacityAt47, fractionDigits: 0)",
+            valueLabel: "BTU/h"
+          )
+        }
+        div {
+          VerticalGroup(
+            label: "Capacity @ 17°",
+            value: "\(double: result.capacityAt17, fractionDigits: 0)",
+            valueLabel: "BTU/h"
+          )
+        }
+      }
+    }
+  }
+
+}
+
+private extension HeatingBalancePoint.Mode {
+  var label: String { rawValue.capitalized }
+}
+
+private extension HeatingBalancePoint.HeatLoss.Mode {
+  var label: String { rawValue.capitalized }
+}
+
+private extension HeatingBalancePoint.Response {
+  var mode: HeatingBalancePoint.Mode {
+    switch self {
+    case .thermal: return .thermal
+    }
+  }
+
+  var warnings: [String] {
+    switch self {
+    case let .thermal(result): return result.warnings
+    }
+  }
+}