PersistenceSyncManager.swift

import Foundation

final class PersistenceSyncManager {
    private let fileManager: FileManager = .default
    private let sharedContainer: URL
    private let sharedTargetPath: String = "YOUR-SHARED-FOLDER"
    private var contentContainerURL: URL { sharedContainer.appendingPathComponent(sharedTargetPath) }

    static let shared = PersistenceSyncManager()

    private convenience init() {
        guard let containerURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "YOUR-APP-GROUP") else {
            fatalError()
        }
        self.init(sharedContainer: containerURL)
    }

    private init(sharedContainer: URL) {
        self.sharedContainer = sharedContainer
    }

    func copyContentsToSharedTarget(from url: URL) throws {
        if fileManager.fileExists(atPath: contentContainerURL.path) {
            try fileManager.removeItem(at: contentContainerURL)
        }
        try fileManager.copyItem(atPath: url.path, toPath: contentContainerURL.path)
    }

    func copyContentsFromSharedTarget(to url: URL) throws {
        if !fileManager.fileExists(atPath: contentContainerURL.path) {
            return
        }

        if fileManager.fileExists(atPath: url.path) {
            try fileManager.removeItem(at: url)
        }

        try fileManager.copyItem(atPath: contentContainerURL.path, toPath: url.path)
    }
}