Out of Comfort Zone

- (instancetype)init {
self = [super init];

NSLog(@"%s launched from %@ ; compiled at %s", __PRETTY_FUNCTION__, [[NSBundle mainBundle] bundlePath], __TIME__);

// Set up the directory we are syncing.
self.myFolderURL = [NSURL fileURLWithPath:@"/Users/Shared/MySyncExtension Documents"];
[FIFinderSyncController defaultController].directoryURLs = [NSSet setWithObject:self.myFolderURL];

// Set up images for our badge identifiers. For demonstration purposes, this uses off-the-shelf images.
[[FIFinderSyncController defaultController] setBadgeImage:[NSImage imageNamed: NSImageNameColorPanel] label:@"Status One" forBadgeIdentifier:@"One"];
[[FIFinderSyncController defaultController] setBadgeImage:[NSImage imageNamed: NSImageNameCaution] label:@"Status Two" forBadgeIdentifier:@"Two"];

return self;
}

- (void)beginObservingDirectoryAtURL:(NSURL *)url {
// The user is now seeing the container's contents.
// If they see it in more than one view at a time, we're only told once.
NSLog(@"beginObservingDirectoryAtURL:%@", url.filePathURL);
}

- (void)endObservingDirectoryAtURL:(NSURL *)url {
// The user is no longer seeing the container's contents.
NSLog(@"endObservingDirectoryAtURL:%@", url.filePathURL);
}

- (void)requestBadgeIdentifierForURL:(NSURL *)url {
NSLog(@"requestBadgeIdentifierForURL:%@", url.filePathURL);

// For demonstration purposes, this picks one of our two badges, or no badge at all, based on the filename.
NSInteger whichBadge = [url.filePathURL hash] % 3;
NSString* badgeIdentifier = @[@"", @"One", @"Two"][whichBadge];
[[FIFinderSyncController defaultController] setBadgeIdentifier:badgeIdentifier forURL:url];
}

- (NSMenu *)menuForMenuKind:(FIMenuKind)whichMenu {
    // Produce a menu for the extension.
    NSMenu *menu = [[NSMenu alloc] initWithTitle:@""];
    [menu addItemWithTitle:@"Example Menu Item" action:@selector(sampleAction:) keyEquivalent:@""];

    return menu;
}

- (NSString *)toolbarItemName {
  return @"FinderSynTest";
}

- (NSString *)toolbarItemToolTip {
  return @"FinderSynTest: Click the toolbar item for a menu.";
}

- (NSImage *)toolbarItemImage {
  return [NSImage imageNamed:NSImageNameCaution];
}

<key>NSUbiquitousContainers</key>
<dict>
    <key>iCloud.com.example.MyApp</key>
    <dict>
        <key>NSUbiquitousContainerIsDocumentScopePublic</key>
        <true/>
        <key>NSUbiquitousContainerSupportedFolderLevels</key>
        <string>Any</string>
        <key>NSUbiquitousContainerName</key>
        <string>MyApp</string>
    </dict>
</dict>

<dict>
<key>NSExtensionAttributes</key>
<dict>
    <key>UIDocumentPickerModes</key>
    <array>
        <string>UIDocumentPickerModeImport</string>
        <string>UIDocumentPickerModeOpen</string>
        <string>UIDocumentPickerModeExportToService</string>
        <string>UIDocumentPickerModeMoveToService</string>
    </array>
    <key>UIDocumentPickerSupportedFileTypes</key>
    <array>
        <string>public.content</string>
    </array>
</dict>
<key>NSExtensionMainStoryboard</key>
<string>MainInterface</string>
<key>NSExtensionPointIdentifier</key>
<string>com.apple.fileprovider-ui</string>
</dict>

<key>NSExtension</key>
<dict>
    <key>NSExtensionAttributes</key>
    <key>NSExtensionFileProviderDocumentGroup</key>
        <string>com.apple.devpubs</string>
    <key>NSExtensionPointIdentifier</key>
    <string>com.apple.fileprovider-nonui</string>
    <key>NSExtensionPrincipalClass</key>
    <string>FileProvider</string>
</dict>

<key>com.apple.security.application-groups</key>
<array>
     <string>com.apple.devpubs</string>
</array>

+ (BOOL)writePlaceholderAtURL:(NSURL *)placeholderURL withMetadata:(NSDictionary *)metadata error:(NSError **)error;
+ (NSURL *)placeholderURLForURL:(NSURL *)url;

- (void)providePlaceholderAtURL:(NSURL *)url completionHandler:(void (^)(NSError *error))completionHandler {
    // Should call + writePlaceholderAtURL:withMetadata:error: with the placeholder URL, then call the completion handler with the error if applicable.
    NSString* fileName = [url lastPathComponent];

    NSURL *placeholderURL = [NSFileProviderExtension placeholderURLForURL:[self.documentStorageURL URLByAppendingPathComponent:fileName]];

    NSUInteger fileSize = 0;
    // TODO: get file size for file at <url> from model

    [self.fileCoordinator coordinateWritingItemAtURL:placeholderURL options:0 error:NULL byAccessor:^(NSURL *newURL) {

        NSDictionary* metadata = @{ NSURLFileSizeKey : @(fileSize)};
        [NSFileProviderExtension writePlaceholderAtURL:placeholderURL withMetadata:metadata error:NULL];
    }];
    if (completionHandler) {
        completionHandler(nil);
    }
}
- (void)startProvidingItemAtURL:(NSURL *)url completionHandler:(void (^)(NSError *))completionHandler {
    // Should ensure that the actual file is in the position returned by URLForItemWithIdentifier:, then call the completion handler
    NSError* error = nil;
    __block NSError* fileError = nil;

    NSData * fileData = [NSData data];
    // TODO: get the contents of file at <url> from model

    [self.fileCoordinator coordinateWritingItemAtURL:url options:0 error:&error byAccessor:^(NSURL *newURL) {
        [fileData writeToURL:newURL options:0 error:&fileError];
    }];
    if (error!=nil) {
        completionHandler(error);
    } else {
        completionHandler(fileError);
    }
}

- (void)itemChangedAtURL:(NSURL *)url {
    // Called at some point after the file has changed; the provider may then trigger an upload

    // TODO: mark file at <url> as needing an update in the model; kick off update process
    NSLog(@"Item changed at URL %@", url);
}

- (void)stopProvidingItemAtURL:(NSURL *)url {
    // Called after the last claim to the file has been released. At this point, it is safe for the file provider to remove the content file.
    // Care should be taken that the corresponding placeholder file stays behind after the content file has been deleted.

    [self.fileCoordinator coordinateWritingItemAtURL:url options:NSFileCoordinatorWritingForDeleting error:NULL byAccessor:^(NSURL *newURL) {
        [[NSFileManager defaultManager] removeItemAtURL:newURL error:NULL];
    }];
    [self providePlaceholderAtURL:url completionHandler:NULL];
}

// An identifier unique to this provider.
// When modifying the files stored in the directory returned by documentStorageURL, you should pass this identifier
// to your file coordinator's setPurposeIdentifier: method.
// By default, this returns the bundle identifier of the application containing your extension. You need to make sure to use the same identifier in your containing app.
- (NSString *)providerIdentifier;

// The root URL for provided documents. This URL must be writable from your app extension, and must only be used for the extension's files or their placeholders.
- (NSURL *)documentStorageURL;

// Should return the URL corresponding to a specific identifier. Fail if it's not a subpath of documentStorageURL.
// This is a static mapping; each identifier must always return a path corresponding to the same file.
// By default, this returns the path relative to the path returned by documentStorageURL.
- (NSURL *)URLForItemWithPersistentIdentifier:(NSString *)identifier;
- (NSString *)persistentIdentifierForItemAtURL:(NSURL *)url;