Add features with contingent values

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// Copyright 2024 Esri
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import ArcGIS
import SwiftUI

struct AddFeaturesWithContingentValuesView: View {
    /// The view model for the sample.
    @StateObject private var model = Model()

    /// The point on the map where the user tapped.
    @State private var tapLocation: Point?

    /// A Boolean value indicating whether the add feature sheet is presented.
    @State private var addFeatureSheetIsPresented = false

    /// The error shown in the error alert.
    @State private var error: Error?

    var body: some View {
        GeometryReader { geometryProxy in
            MapViewReader { mapViewProxy in
                MapView(map: model.map, graphicsOverlays: [model.graphicsOverlay])
                    .onSingleTapGesture { _, mapPoint in
                        tapLocation = mapPoint
                    }
                    .task(id: tapLocation) {
                        // Add a feature representing a bird's nest when the map is tapped.
                        guard let tapLocation else { return }

                        do {
                            try await model.addFeature(at: tapLocation)
                            addFeatureSheetIsPresented = true

                            // Create an envelope from the screen's frame.
                            let viewRect = geometryProxy.frame(in: .local)
                            guard let viewExtent = mapViewProxy.envelope(
                                fromViewRect: viewRect
                            ) else { return }

                            // Update the map's viewpoint with an offsetted tap location
                            // to center the feature in the top half of the screen.
                            let yOffset = (viewExtent.height / 2) / 2
                            let newViewpointCenter = Point(
                                x: tapLocation.x,
                                y: tapLocation.y - yOffset
                            )
                            await mapViewProxy.setViewpointCenter(newViewpointCenter)
                        } catch {
                            self.error = error
                        }
                    }
                    .task {
                        do {
                            // Load the features from the geodatabase when the sample loads.
                            try await model.loadFeatures()

                            // Zoom to the extent of the added layer.
                            guard let extent = model.map.operationalLayers.first?.fullExtent
                            else { return }
                            await mapViewProxy.setViewpointGeometry(extent, padding: 15)
                        } catch {
                            self.error = error
                        }
                    }
            }
        }
        .overlay(alignment: .bottom) {
            // A workaround that allows the popover to display at the bottom of
            // the screen on Mac Catalyst.
            EmptyView()
                .frame(width: 1, height: 1)
                .padding()
                .popover(isPresented: $addFeatureSheetIsPresented, arrowEdge: .bottom) {
                    NavigationStack {
                        AddFeatureView(model: model)
                            .navigationTitle("Add Bird Nest")
                            .navigationBarTitleDisplayMode(.inline)
                            .toolbar {
                                ToolbarItem(placement: .cancellationAction) {
                                    Button("Cancel", role: .cancel) {
                                        addFeatureSheetIsPresented = false
                                    }
                                }

                                ToolbarItem(placement: .confirmationAction) {
                                    Button("Done") {
                                        model.feature = nil
                                        addFeatureSheetIsPresented = false
                                    }
                                    .disabled(!model.contingenciesAreValid)
                                }
                            }
                    }
                    .presentationDetents([.fraction(0.5)])
                    .frame(idealWidth: 320, idealHeight: 320)
                }
                .task(id: addFeatureSheetIsPresented) {
                    // When the sheet closes, remove the feature if it is invalid.
                    guard !addFeatureSheetIsPresented, model.feature != nil else { return }

                    do {
                        try await model.removeFeature()
                    } catch {
                        self.error = error
                    }
                }
        }
        .errorAlert(presentingError: $error)
    }
}