feat: GutenbergKit Media Library support (#23721)

* wip: GutenbergKit Media Library support

* fix: JSON encode media array and pass as string to WebView

* fix: Prevent global callback collisions

A single Media Library callback resulted in erroneously mutating
unselected blocks.

* refactor: Remove Media Library UUID usage

Unable to recreate the original erroneously replacement of media
attachments for unselected blocks. This now feels unnecessary.

* style: Remove unnecessary white space

Address lint warning.

* feat: Media Library preserves initial selection

Enable retaining selection for gallery addition/editing in the block
editor.

* refactor: Remove unnecessary preserveSelection parameter

Reusing the `initialSelection` reduces complexity.

* fix: Reinstate commented selection clearing code

This no longer disrupts initial selection as the setting the initial
selection now occurs within `setEditing` rather than initialization.

* refactor: Remove unnecessary application of initial selection

This appears to be unnecessary with the latest implementation.

* refactor: Remove unused `preserveSelection` parameter

* fix: Canceling media selection returns initial selection

Without returning the initial selection, canceling cleared out media
attached to Gallery blocks in the web-based editor, as it presumes the
existing media will be returned as "selected."

* fix: Discard initial selection for single select

Workaround existing logic that dismisses the dialog if `allowMuliple` is
true and selection is not empty. The existing logic allows for quickly
selecting a single media item, but inhibits the ability to showcase a
pre-existing selection for single-select contexts. This diverges from
the web experience, but is the easiest path forward to avoid a
significant refactor of the logic that would impact all other existing
use cases--Gutenberg Mobile, Aztec, etc.

* fix: Ensure correct media attachment sorting

Map the Media lookup results to the original array of media IDs so that
the sort order is preserved.

* build: Update GutenbergKit ref

* build: Update GutenbergKit ref

* docs: Expand existing documentation to include new parameter

* refactor: Update bridge method name to mirror GutenbergKit

* refactor: Rename `OpenMediaLibrary` to `OpenMediaLibraryAction`

Improve clarity.

* fix: Include VideoPress ID in metadata

* fix: Account for null `allowedTypes` values

The File block does not provide these value.

* fix: Assert main thread for `mapMediaIdsToMedia`

The returned `Media` entities are not thread-safe.

* build: Update GutenbergKit ref

* build: Update GutenbergKit ref

Modules/Package.swift

@@ -47,7 +47,7 @@ let package = Package(
         .package(url: "https://github.com/zendesk/support_sdk_ios", from: "8.0.3"),
         // We can't use wordpress-rs branches nor commits here. Only tags work.
         .package(url: "https://github.com/Automattic/wordpress-rs", revision: "alpha-swift-20240813"),
-        .package(url: "https://github.com/wordpress-mobile/GutenbergKit", revision: "849118af582068f75807bc0f1265edeee4bf1b5e"),
+        .package(url: "https://github.com/wordpress-mobile/GutenbergKit", revision: "6cc307e7fc24910697be5f71b7d70f465a9c0f63"),
         .package(url: "https://github.com/Automattic/color-studio", branch: "trunk"),
     ],
     targets: XcodeSupport.targets + [

WordPress.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -149,7 +149,7 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/wordpress-mobile/GutenbergKit",
       "state" : {
-        "revision" : "849118af582068f75807bc0f1265edeee4bf1b5e"
+        "revision" : "6cc307e7fc24910697be5f71b7d70f465a9c0f63"
       }
     },
     {

WordPress/Classes/ViewRelated/Gutenberg/GutenbergMediaPickerHelper.swift

@@ -38,12 +38,37 @@ final class GutenbergMediaPickerHelper: NSObject {
         context.present(picker, animated: true)
     }
 
-    func presentSiteMediaPicker(filter: WPMediaType, allowMultipleSelection: Bool, completion: @escaping GutenbergMediaPickerHelperCallback) {
+    func presentSiteMediaPicker(filter: WPMediaType, allowMultipleSelection: Bool, initialSelection: [Int] = [], completion: @escaping GutenbergMediaPickerHelperCallback) {
         didPickMediaCallback = completion
-        MediaPickerMenu(viewController: context, filter: .init(filter), isMultipleSelectionEnabled: allowMultipleSelection)
+        let initialMediaSelection = mapMediaIdsToMedia(initialSelection)
+        MediaPickerMenu(viewController: context, filter: .init(filter), isMultipleSelectionEnabled: allowMultipleSelection, initialSelection: initialMediaSelection)
             .showSiteMediaPicker(blog: post.blog, delegate: self)
     }
 
+    private func mapMediaIdsToMedia(_ mediaIds: [Int]) -> [Media] {
+        assert(Thread.isMainThread, "mapMediaIdsToMedia should only be called on the main thread")
+        let context = ContextManager.shared.mainContext
+        let request = NSFetchRequest<NSManagedObject>(entityName: "Media")
+        request.predicate = NSPredicate(format: "mediaID IN %@", mediaIds.map { NSNumber(value: $0) })
+
+        do {
+            let fetchedMedia = try context.fetch(request) as? [Media] ?? []
+
+            // Create a dictionary for quick lookup
+            let mediaDict = Dictionary(uniqueKeysWithValues: fetchedMedia.compactMap { media -> (Int, Media)? in
+                if let mediaID = media.mediaID?.intValue {
+                    return (mediaID, media)
+                }
+                return nil
+            })
+
+            // Map the original mediaIds to Media objects, preserving order
+            return mediaIds.compactMap { mediaDict[$0] }
+        } catch {
+            return []
+        }
+    }
+
     func presentCameraCaptureFullScreen(animated: Bool,
                                         filter: WPMediaType,
                                         callback: @escaping GutenbergMediaPickerHelperCallback) {

WordPress/Classes/ViewRelated/Media/MediaPickerMenu.swift

@@ -9,6 +9,7 @@ struct MediaPickerMenu {
     weak var presentingViewController: UIViewController?
     var filter: MediaFilter?
     var isMultipleSelectionEnabled: Bool
+    var initialSelection: [Media]
 
     enum MediaFilter {
         case images
@@ -21,12 +22,15 @@ struct MediaPickerMenu {
     ///   - viewController: The view controller to use for presentation.
     ///   - filter: By default, `nil` – allow all content types.
     ///   - isMultipleSelectionEnabled: By default, `false`.
+    ///   - initialSelection: By default, `[]`.
     init(viewController: UIViewController,
          filter: MediaFilter? = nil,
-         isMultipleSelectionEnabled: Bool = false) {
+         isMultipleSelectionEnabled: Bool = false,
+         initialSelection: [Media] = []) {
         self.presentingViewController = viewController
         self.filter = filter
         self.isMultipleSelectionEnabled = isMultipleSelectionEnabled
+        self.initialSelection = initialSelection
     }
 }
 
@@ -185,7 +189,8 @@ extension MediaPickerMenu {
         let viewController = SiteMediaPickerViewController(
             blog: blog,
             filter: filter.map { [$0.mediaType] },
-            allowsMultipleSelection: isMultipleSelectionEnabled
+            allowsMultipleSelection: isMultipleSelectionEnabled,
+            initialSelection: initialSelection
         )
         viewController.delegate = delegate
         let navigation = UINavigationController(rootViewController: viewController)

WordPress/Classes/ViewRelated/Media/SiteMedia/Controllers/SiteMediaCollectionViewController.swift

@@ -73,6 +73,14 @@ final class SiteMediaCollectionViewController: UIViewController, NSFetchedResult
         fatalError("init(coder:) has not been implemented")
     }
 
+    private func setInitialSelection(_ media: [Media]) {
+        updateSelection {
+            for item in media {
+                selection.add(item)
+            }
+        }
+    }
+
     func embed(in parentViewController: UIViewController) {
         parentViewController.addChild(self)
         parentViewController.view.addSubview(view)
@@ -159,14 +167,19 @@ final class SiteMediaCollectionViewController: UIViewController, NSFetchedResult
     func setEditing(
         _ isEditing: Bool,
         allowsMultipleSelection: Bool = true,
-        isSelectionOrdered: Bool = false
+        isSelectionOrdered: Bool = false,
+        initialSelection: [Media]? = nil
     ) {
         guard self.isEditing != isEditing else { return }
         self.isEditing = isEditing
         self.allowsMultipleSelection = allowsMultipleSelection
         self.isSelectionOrdered = isSelectionOrdered
 
-        deselectAll()
+        if let selectedMedia = initialSelection, allowsMultipleSelection {
+            setInitialSelection(selectedMedia)
+        } else {
+            deselectAll()
+        }
     }
 
     private func updateSelection(_ perform: () -> Void) {

WordPress/Classes/ViewRelated/Media/SiteMedia/SiteMediaPickerViewController.swift

@@ -9,6 +9,7 @@ protocol SiteMediaPickerViewControllerDelegate: AnyObject {
 final class SiteMediaPickerViewController: UIViewController, SiteMediaCollectionViewControllerDelegate {
     private let blog: Blog
     private let allowsMultipleSelection: Bool
+    private let initialSelection: [Media]
 
     private let collectionViewController: SiteMediaCollectionViewController
     private let toolbarItemTitle = SiteMediaSelectionTitleView()
@@ -22,9 +23,11 @@ final class SiteMediaPickerViewController: UIViewController, SiteMediaCollection
     ///   - blog: The site that contains the media
     ///   - filter: The types of media to display. By default, `nil` (show everything).
     ///   - allowsMultipleSelection: `false` by default.
-    init(blog: Blog, filter: Set<MediaType>? = nil, allowsMultipleSelection: Bool = false) {
+    ///   - initialSelection: `[]` by default.
+    init(blog: Blog, filter: Set<MediaType>? = nil, allowsMultipleSelection: Bool = false, initialSelection: [Media] = []) {
         self.blog = blog
         self.allowsMultipleSelection = allowsMultipleSelection
+        self.initialSelection = initialSelection
         self.collectionViewController = SiteMediaCollectionViewController(blog: blog, filter: filter, isShowingPendingUploads: false)
 
         super.init(nibName: nil, bundle: nil)
@@ -65,7 +68,7 @@ final class SiteMediaPickerViewController: UIViewController, SiteMediaCollection
     // MARK: - Actions
 
     private func buttonCancelTapped() {
-        delegate?.siteMediaPickerViewController(self, didFinishWithSelection: [])
+        delegate?.siteMediaPickerViewController(self, didFinishWithSelection: initialSelection)
     }
 
     @objc private func buttonDoneTapped() {
@@ -75,7 +78,7 @@ final class SiteMediaPickerViewController: UIViewController, SiteMediaCollection
     // MARK: - Selection
 
     private func startSelection() {
-        collectionViewController.setEditing(true, allowsMultipleSelection: allowsMultipleSelection, isSelectionOrdered: true)
+        collectionViewController.setEditing(true, allowsMultipleSelection: allowsMultipleSelection, isSelectionOrdered: true, initialSelection: initialSelection)
 
         if allowsMultipleSelection, toolbarItems == nil {
             var toolbarItems: [UIBarButtonItem] = []

WordPress/Classes/ViewRelated/NewGutenberg/NewGutenbergViewController.swift

@@ -21,6 +21,10 @@ class NewGutenbergViewController: UIViewController, PostEditor, PublishingEditor
         SupportCoordinator(controllerToShowFrom: topmostPresentedViewController, tag: .editorHelp)
     }()
 
+    lazy var mediaPickerHelper: GutenbergMediaPickerHelper = {
+        return GutenbergMediaPickerHelper(context: self, post: post)
+    }()
+
     // MARK: - PostEditor
 
     private(set) lazy var postEditorStateContext: PostEditorStateContext = {
@@ -335,6 +339,73 @@ extension NewGutenbergViewController: GutenbergKit.EditorViewControllerDelegate
     func editor(_ viewController: GutenbergKit.EditorViewController, performRequest: GutenbergKit.EditorNetworkRequest) async throws -> GutenbergKit.EditorNetworkResponse {
         throw URLError(.unknown)
     }
+
+    func editor(_ viewController: GutenbergKit.EditorViewController, didRequestMediaFromSiteMediaLibrary config: OpenMediaLibraryAction) {
+        let flags = mediaFilterFlags(using: config.allowedTypes ?? [])
+
+        let initialSelectionArray: [Int]
+        switch config.value {
+        case .single(let id):
+            initialSelectionArray = [id]
+        case .multiple(let ids):
+            initialSelectionArray = ids
+        case .none:
+            initialSelectionArray = []
+        }
+
+        mediaPickerHelper.presentSiteMediaPicker(filter: flags, allowMultipleSelection: config.multiple, initialSelection: initialSelectionArray) { [weak self] assets in
+            guard let self, let media = assets as? [Media] else {
+                self?.editorViewController.setMediaUploadAttachment("[]")
+                return
+            }
+            let mediaInfos = media.map { item in
+                var metadata: [String: String] = [:]
+                if let videopressGUID = item.videopressGUID {
+                    metadata["videopressGUID"] = videopressGUID
+                }
+                return MediaInfo(id: item.mediaID?.int32Value, url: item.remoteURL, type: item.mediaTypeString, caption: item.caption, title: item.filename, alt: item.alt, metadata: [:])
+            }
+            if let jsonString = convertMediaInfoArrayToJSONString(mediaInfos) {
+                // Escape the string for JavaScript
+                let escapedJsonString = jsonString.replacingOccurrences(of: "'", with: "\\'")
+                editorViewController.setMediaUploadAttachment(escapedJsonString)
+            }
+        }
+    }
+
+    private func convertMediaInfoArrayToJSONString(_ mediaInfoArray: [MediaInfo]) -> String? {
+        do {
+            let jsonData = try JSONEncoder().encode(mediaInfoArray)
+            if let jsonString = String(data: jsonData, encoding: .utf8) {
+                return jsonString
+            }
+        } catch {
+            print("Error encoding MediaInfo array: \(error)")
+        }
+        return nil
+    }
+
+    private func mediaFilterFlags(using filterArray: [OpenMediaLibraryAction.MediaType]) -> WPMediaType {
+        var mediaType: Int = 0
+        for filter in filterArray {
+            switch filter {
+            case .image:
+                mediaType = mediaType | WPMediaType.image.rawValue
+            case .video:
+                mediaType = mediaType | WPMediaType.video.rawValue
+            case .audio:
+                mediaType = mediaType | WPMediaType.audio.rawValue
+            case .other:
+                mediaType = mediaType | WPMediaType.other.rawValue
+            case .any:
+                mediaType = mediaType | WPMediaType.all.rawValue
+            @unknown default:
+                fatalError()
+            }
+        }
+
+        return WPMediaType(rawValue: mediaType)
+    }
 }
 
 private struct NewGutenbergNetworkClient: GutenbergKit.EditorNetworkingClient {