Implemented the SaveDocumentPicker component for the Browse module.

Modules/Sources/Browse/UI/Components/SaveDocumentPicker.swift

@@ -0,0 +1,120 @@
+//
+//  SaveDocumentPicker.swift
+//  Browse
+//
+//  Created by Javier Cicchelli on 17/12/2022.
+//  Copyright © 2022 Röck+Cöde. All rights reserved.
+//
+
+import Foundation
+import SwiftUI
+import UIKit
+
+struct SaveDocumentPicker: UIViewControllerRepresentable {
+
+    // MARK: Type aliases
+
+    typealias DownloadedClosure = (NSError?) -> Void
+    typealias CancelledClosure = () -> Void
+
+    // MARK: Properties
+
+    private let fileName: String
+    private let fileData: Data
+    private let downloaded: DownloadedClosure
+    private let cancelled: CancelledClosure?
+
+    // MARK: Initialisers
+
+    init(
+        fileName: String,
+        fileData: Data,
+        downloaded: @escaping DownloadedClosure,
+        cancelled: CancelledClosure? = nil
+    ) {
+        self.fileName = fileName
+        self.fileData = fileData
+        self.downloaded = downloaded
+        self.cancelled = cancelled
+    }
+
+    // MARK: Functions
+
+    func makeUIViewController(context: Context) -> UIDocumentPickerViewController {
+        let controller = UIDocumentPickerViewController(
+            forOpeningContentTypes: [.folder]
+        )
+
+        controller.allowsMultipleSelection = false
+        controller.shouldShowFileExtensions = false
+        controller.delegate = context.coordinator
+
+        return controller
+    }
+
+    func updateUIViewController(
+        _ uiViewController: UIDocumentPickerViewController,
+        context: Context
+    ) { }
+
+    func makeCoordinator() -> Coordinator {
+        .init(self)
+    }
+}
+
+// MARK: - Coordinators
+
+extension SaveDocumentPicker {
+    class Coordinator: NSObject, UIDocumentPickerDelegate {
+
+        // MARK: Properties
+
+        private let parent: SaveDocumentPicker
+        private let fileCoordinator: NSFileCoordinator = .init()
+        private let fileManager: FileManager = .default
+
+        // MARK: Initialisers
+
+        init(_ parent: SaveDocumentPicker) {
+            self.parent = parent
+        }
+
+        // MARK: UIDocumentPickerDelegate
+
+        func documentPicker(
+            _ controller: UIDocumentPickerViewController,
+            didPickDocumentsAt urls: [URL]
+        ) {
+            guard
+                let url = urls.first,
+                url.startAccessingSecurityScopedResource()
+            else {
+                // TODO: Handle this error appropriately.
+                return
+            }
+            
+            var error: NSError?
+            
+            fileCoordinator.coordinate(
+                writingItemAt: url,
+                error: &error
+            ) { url in
+                fileManager.createFile(
+                    atPath: url.appendingPathComponent(parent.fileName).relativePath,
+                    contents: parent.fileData
+                )
+            }
+            
+            url.stopAccessingSecurityScopedResource()
+            
+            parent.downloaded(error)
+        }
+
+        func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
+            controller.dismiss(animated: true) { [weak self] in
+                self?.parent.cancelled?()
+            }
+        }
+
+    }
+}