//
//  FileProviderEnumerator.swift
//  SimpleX Service
//
//  Created by Evgeny on 01/06/2022.
//  Copyright © 2022 SimpleX Chat. All rights reserved.
//

import FileProvider

class FileProviderEnumerator: NSObject, NSFileProviderEnumerator {
    
    var enumeratedItemIdentifier: NSFileProviderItemIdentifier
    
    init(enumeratedItemIdentifier: NSFileProviderItemIdentifier) {
        logger.debug("FileProviderExtension FileProviderEnumerator.init")
        self.enumeratedItemIdentifier = enumeratedItemIdentifier
        super.init()
    }

    func identifierForItemAtURL(_ url: URL, completionHandler: @escaping (NSFileProviderItemIdentifier) -> Void) {
//        logger.debug("FileProviderExtension.identifierForItemAtURL")
        completionHandler(SERVICE_PROXY_ITEM_ID)
    }

    func invalidate() {
        // TODO: perform invalidation of server connection if necessary
    }

    func enumerateItems(for observer: NSFileProviderEnumerationObserver, startingAt page: NSFileProviderPage) {
        /* TODO:
         - inspect the page to determine whether this is an initial or a follow-up request
         
         If this is an enumerator for a directory, the root container or all directories:
         - perform a server request to fetch directory contents
         If this is an enumerator for the active set:
         - perform a server request to update your local database
         - fetch the active set from your local database
         
         - inform the observer about the items returned by the server (possibly multiple times)
         - inform the observer that you are finished with this page
         */
    }
    
    func enumerateChanges(for observer: NSFileProviderChangeObserver, from anchor: NSFileProviderSyncAnchor) {
        /* TODO:
         - query the server for updates since the passed-in sync anchor
         
         If this is an enumerator for the active set:
         - note the changes in your local database
         
         - inform the observer about item deletions and updates (modifications + insertions)
         - inform the observer when you have finished enumerating up to a subsequent sync anchor
         */
    }

}