feat: Adds airflow at pressure feature.

Sources/AirflowAtPressureFeature/AirflowAtPressure.swift

@@ -0,0 +1,189 @@
+import ComposableArchitecture
+import EstimatedPressureDependency
+import SharedModels
+import Styleguide
+import SwiftUI
+
+@Reducer
+public struct AirflowAtPressureFeature {
+
+  @ObservableState
+  public struct State: Equatable {
+    public var isPresentingInfoView: Bool = false
+    public var existingAirflow: Double?
+    public var existingPressure: Double?
+    public var targetPressure: Double?
+    public var calculatedAirflow: Positive<Double>?
+
+    public init(
+      existingAirflow: Double? = nil,
+      existingPressure: Double? = nil,
+      targetPressure: Double? = 0.5,
+      calculatedAirflow: Positive<Double>? = nil
+    ) {
+      self.existingAirflow = existingAirflow
+      self.existingPressure = existingPressure
+      self.targetPressure = targetPressure
+      self.calculatedAirflow = calculatedAirflow
+    }
+
+    public var isValid: Bool {
+      existingAirflow != nil
+      && existingPressure != nil
+      && targetPressure != nil
+    }
+  }
+
+  public enum Action: BindableAction, ViewAction {
+    case binding(BindingAction<State>)
+    case receive(ReceiveAction)
+    case view(View)
+
+    @CasePathable
+    public enum ReceiveAction {
+      case calculatedAirflow(Positive<Double>?)
+    }
+
+    @CasePathable
+    public enum View {
+      case dismissInfoViewButtonTapped
+      case infoButtonTapped
+      case resetButtonTapped
+      case submit
+    }
+  }
+  
+
+  @Dependency(\.estimatedPressuresClient) var estimatedPressuresClient
+
+  public var body: some Reducer<State, Action> {
+    BindingReducer()
+    Reduce<State, Action> { state, action in
+      switch action {
+      case .binding:
+        return .none
+
+      case let .receive(action):
+        switch action {
+        case let .calculatedAirflow(airflow):
+          state.calculatedAirflow = airflow
+          return .none
+        }
+
+      case let .view(action):
+        switch action {
+        case .dismissInfoViewButtonTapped:
+          state.isPresentingInfoView = false
+          return .none
+
+        case .infoButtonTapped:
+          state.isPresentingInfoView = true
+          return .none
+
+        case .resetButtonTapped:
+          state = .init()
+          return .none
+
+        case .submit:
+          guard state.isValid else { return .none }
+          return .run { [state] send in
+            await send(
+              .receive(.calculatedAirflow(
+                try? await estimatedPressuresClient.estimatedAirflow(.init(
+                  existingAirflow: state.existingAirflow ?? 0,
+                  existingPressure: state.existingPressure ?? 0,
+                  targetPressure: state.targetPressure ?? 0
+                ))
+              ))
+            )
+          }
+
+        }
+      }
+    }
+  }
+}
+
+@ViewAction(for: AirflowAtPressureFeature.self)
+public struct AirflowAtPressureView: View {
+
+  @Perception.Bindable
+  public var store: StoreOf<AirflowAtPressureFeature>
+
+  public init(store: StoreOf<AirflowAtPressureFeature>) {
+    self.store = store
+  }
+
+  public var body: some View {
+    Form {
+      Section {
+        TextField(
+          "Existing Airflow",
+          value: $store.existingAirflow,
+          format: .number,
+          prompt: Text("Airflow")
+        )
+        .onSubmit { send(.submit) }
+        .numberPad()
+
+        TextField(
+          "Existing Pressure",
+          value: $store.existingPressure,
+          format: .number,
+          prompt: Text("Existing Pressure")
+        )
+        .onSubmit { send(.submit) }
+        .decimalPad()
+
+        TextField(
+          "Target Pressure",
+          value: $store.targetPressure,
+          format: .number,
+          prompt: Text("Target Pressure")
+        )
+        .onSubmit { send(.submit) }
+        .decimalPad()
+
+      } header: {
+        HStack {
+          Text("Inputs")
+          Spacer()
+          InfoButton { send(.infoButtonTapped) }
+        }
+        .labelStyle(.iconOnly)
+      } footer: {
+        HStack {
+          Spacer()
+          Button("Reset") { send(.resetButtonTapped) }
+          Spacer()
+        }
+        .padding(.top)
+        .buttonStyle(.borderedProminent)
+      }
+
+      Section {
+        if let airflow = store.calculatedAirflow {
+          Text(airflow.positiveValue, format: .number.precision(.fractionLength(0)))
+        }
+      } header: {
+        Text("Calculated Airflow")
+      }
+    }
+    .sheet(isPresented: $store.isPresentingInfoView) {
+      NavigationStack {
+        AirflowAtPressureInfoView()
+          .toolbar {
+            Button("Done") { send(.dismissInfoViewButtonTapped) }
+          }
+      }
+    }
+  }
+}
+
+#Preview {
+  AirflowAtPressureView(
+    store: Store(initialState: AirflowAtPressureFeature.State()) {
+      AirflowAtPressureFeature()
+    }
+  )
+}