Search for web map

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

    /// The text query in the search bar.
    @State private var query = ""

    /// A Boolean value indicating whether new results are being loaded.
    @State private var resultsAreLoading = false

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

    var body: some View {
        ScrollView {
            LazyVStack {
                ForEach(model.portalItems, id: \.id) { item in
                    NavigationLink {
                        SafeMapView(map: Map(item: item))
                            .navigationTitle(item.title)
                    } label: {
                        PortalItemRowView(item: item)
                    }
                    .buttonStyle(.plain)
                    .task {
                        // Load the next results when the last item is reached.
                        guard item.id == model.portalItems.last?.id else { return }

                        resultsAreLoading = true
                        defer { resultsAreLoading = false }

                        do {
                            try await model.findNextItems()
                        } catch {
                            self.error = error
                        }
                    }
                }

                if resultsAreLoading {
                    ProgressView()
                        .padding()
                } else if !query.isEmpty && model.portalItems.isEmpty {
                    VStack {
                        Text("No Results")
                            .font(.headline)
                        Text("Check spelling or try a new search.")
                            .font(.footnote)
                    }
                    .padding()
                }
            }
        }
        .background(Color(.secondarySystemBackground))
        .searchable(
            text: $query,
            placement: .navigationBarDrawer(displayMode: .always),
            prompt: "Web Maps"
        )
        .autocorrectionDisabled()
        .task(id: query) {
            // Load new results when the query changes.
            resultsAreLoading = true
            defer { resultsAreLoading = false }

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

#Preview {
    NavigationStack {
        SearchForWebMapView()
    }
}

// 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 Combine
import Foundation

extension SearchForWebMapView {
    /// The view model for the sample.
    @MainActor
    class Model: ObservableObject {
        /// A portal to ArcGIS Online to get the portal items from.
        private let portal = Portal.arcGISOnline(connection: .anonymous)

        /// The query parameters for the next set of results based on the last results.
        private var nextQueryParameters: PortalQueryParameters?

        /// The text query from the last search.
        private var lastQuery = ""

        /// The portal items resulting from a search.
        @Published private(set) var portalItems: [PortalItem] = []

        /// Finds the portal items that match the given query.
        /// - Parameter query: The text query used to find the portal items.
        func findItems(for query: String) async throws {
            // Ensure that a new search is necessary.
            guard query != lastQuery else { return }

            if query.isEmpty {
                portalItems.removeAll()
                return
            }

            // Find the new results using parameters made with the query.
            let parameters = queryParameters(for: query)
            let results = try await portalItems(using: parameters)
            portalItems = results
            lastQuery = query
        }

        /// Finds the next portal item based on the last results.
        func findNextItems() async throws {
            guard let nextQueryParameters else { return }

            // Find the next results using the next query parameters from the last search.
            let nextResults = try await portalItems(using: nextQueryParameters)
            portalItems.append(contentsOf: nextResults)
        }

        /// The portal items from the portal that match the given query parameters.
        /// - Parameter queryParameters: The portal query parameters to find the portal items.
        /// - Returns: The portal items that were found.
        private func portalItems(using queryParameters: PortalQueryParameters) async throws -> [PortalItem] {
            // Get the results from the portal using the parameters.
            let resultsSet = try await portal.findItems(queryParameters: queryParameters)
            nextQueryParameters = resultsSet.nextQueryParameters
            return resultsSet.results
        }

        /// The portal query parameters for a given query.
        /// - Parameter query: The text query used to create the parameters.
        /// - Returns: A new `PortalQueryParameters` object.
        private func queryParameters(for query: String) -> PortalQueryParameters {
            // Create a date string for a date range to search within.
            // Note: Web maps authored prior to July 2nd, 2014 are not supported.
            let startDate = Date.webMapSupportedDate

            // Convert the dates to UNIX time to be able to use with the ArcGIS REST API.
            let dateRange = startDate.unixTime...Date.now.unixTime
            let dateString = "uploaded:[\(dateRange.lowerBound) TO \(dateRange.upperBound)]"

            // Create a string to filter for web maps.
            let typeString = #"type:"Web Map""#

            // Create the portal query parameters with the strings.
            let fullQuery = [query, typeString, dateString].joined(separator: " AND ")
            return PortalQueryParameters(query: fullQuery)
        }
    }
}

private extension Date {
    /// The date after which web maps are supported, July 2, 2014.
    static var webMapSupportedDate: Date {
        try! Date(
            "July 2, 2014",
            strategy: Date.FormatStyle().day().month().year().parseStrategy
        )
    }

    /// The milliseconds between the date value and 00:00:00 UTC on 1 January 1970.
    var unixTime: Int64 {
        Int64(timeIntervalSince1970 * 1_000)
    }
}

// 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

extension SearchForWebMapView {
    /// A map view that shows an alert when there is an error loading the map.
    struct SafeMapView: View {
        /// The map shown in the map view.
        let map: Map

        /// A Boolean value indicating whether the map is being loaded.
        @State private var mapIsLoading = false

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

        var body: some View {
            ZStack {
                MapView(map: map)
                    .onLayerViewStateChanged { _, state in
                        // Show an alert for an error loading any of the layers.
                        guard let error = state.error else { return }
                        self.error = error
                    }
                    .task {
                        mapIsLoading = true
                        defer { mapIsLoading = false }

                        // Show an alert for an error loading the map.
                        do {
                            try await map.load()
                        } catch {
                            self.error = error
                        }
                    }

                if mapIsLoading {
                    ProgressView()
                }
            }
            .errorAlert(presentingError: $error)
        }
    }

    /// A view that shows a given portal item's info in a row.
    struct PortalItemRowView: View {
        /// The portal item to display in the row.
        let item: PortalItem

        var body: some View {
            VStack {
                HStack {
                    AsyncImage(url: item.thumbnail?.url) { image in
                        image
                            .resizable()
                    } placeholder: {
                        Color(.lightGray)
                    }
                    .frame(width: 110, height: 75)
                    .border(.primary)
                    .padding([.leading, .top], 10)

                    Text(item.title)

                    Spacer()
                }

                Divider()
                    .overlay(.black)

                HStack {
                    if let modificationDate = item.modificationDate {
                        Text(modificationDate, format: Date.FormatStyle(date: .abbreviated, time: .omitted))
                    } else {
                        Text("Date: Unknown")
                    }

                    Divider()
                        .overlay(.black)

                    Text(item.owner)
                        .foregroundStyle(Color.accentColor)

                    Spacer()
                }
                .font(.footnote)
                .padding(.top, 2)
                .padding([.horizontal, .bottom], 10)
            }
            .background(Color(.systemGray5))
            .border(Color(.darkGray))
            .padding(.top, 8)
            .padding(.horizontal)
        }
    }
}