Add compose attachments preview

Tusker/Screens/Asset Picker/AssetCollectionViewController.swift

@@ -177,10 +177,11 @@ class AssetCollectionViewController: UICollectionViewController {
     }
     
     override func collectionView(_ collectionView: UICollectionView, previewForHighlightingContextMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
-        if let indexPath = (configuration.identifier as? NSIndexPath) as IndexPath?, let cell = collectionView.cellForItem(at: indexPath) {
+        if let indexPath = (configuration.identifier as? NSIndexPath) as IndexPath?,
+            let cell = collectionView.cellForItem(at: indexPath) as? AssetCollectionViewCell {
             let parameters = UIPreviewParameters()
             parameters.backgroundColor = .black
-            return UITargetedPreview(view: cell, parameters: parameters)
+            return UITargetedPreview(view: cell.imageView, parameters: parameters)
         } else {
             return nil
         }

Tusker/Screens/Asset Picker/AssetPreviewViewController.swift

@@ -13,14 +13,18 @@ import AVKit
 
 class AssetPreviewViewController: UIViewController {
 
-    let asset: PHAsset
+    let attachment: CompositionAttachmentData
     
-    init(asset: PHAsset) {
-        self.asset = asset
+    init(attachment: CompositionAttachmentData) {
+        self.attachment = attachment
 
         super.init(nibName: nil, bundle: nil)
     }
     
+    convenience init(asset: PHAsset) {
+        self.init(attachment: .asset(asset))
+    }
+    
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
@@ -30,21 +34,29 @@ class AssetPreviewViewController: UIViewController {
         
         view.backgroundColor = .black
 
-        if asset.mediaType == .image {
+        switch attachment {
+        case let .image(image):
+            showImage(image)
+        case let .video(url):
+            showVideo(asset: AVURLAsset(url: url))
+        case let .asset(asset):
+            switch asset.mediaType {
+            case .image:
                 if asset.mediaSubtypes.contains(.photoLive) {
-                showLivePhoto()
+                    showLivePhoto(asset)
                 } else {
-                showImage()
+                    showAssetImage(asset)
                 }
-        } else if asset.mediaType == .video {
-            playVideo()
-        } else {
+            case .video:
+                showAssetVideo(asset)
+            default:
                 fatalError("asset mediaType must be image or video")
             }
         }
+    }
     
-    func showImage() {
-        let imageView = UIImageView()
+    func showImage(_ image: UIImage) {
+        let imageView = UIImageView(image: image)
         imageView.translatesAutoresizingMaskIntoConstraints = false
         imageView.contentMode = .scaleAspectFit
         view.addSubview(imageView)
@@ -54,7 +66,10 @@ class AssetPreviewViewController: UIViewController {
             imageView.topAnchor.constraint(equalTo: view.topAnchor),
             imageView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
         ])
+        preferredContentSize = image.size
+    }
     
+    func showAssetImage(_ asset: PHAsset) {
         let options = PHImageRequestOptions()
         options.version = .current
         options.deliveryMode = .opportunistic
@@ -62,13 +77,12 @@ class AssetPreviewViewController: UIViewController {
         options.isNetworkAccessAllowed = true
         PHImageManager.default().requestImage(for: asset, targetSize: view.bounds.size, contentMode: .aspectFit, options: options) { (image, _) in
             DispatchQueue.main.async {
-                imageView.image = image
-                self.preferredContentSize = image!.size
+                self.showImage(image!)
             }
         }
     }
     
-    func showLivePhoto() {
+    func showLivePhoto(_ asset: PHAsset) {
         let options = PHLivePhotoRequestOptions()
         options.deliveryMode = .opportunistic
         options.version = .current
@@ -96,7 +110,18 @@ class AssetPreviewViewController: UIViewController {
         }
     }
     
-    func playVideo() {
+    func showVideo(asset: AVAsset) {
+        let playerController = AVPlayerViewController()
+        let item = AVPlayerItem(asset: asset)
+        let player = AVPlayer(playerItem: item)
+        player.isMuted = true
+        player.play()
+        playerController.player = player
+        self.embedChild(playerController)
+        self.preferredContentSize = item.presentationSize
+    }
+    
+    func showAssetVideo(_ asset: PHAsset) {
         let options = PHVideoRequestOptions()
         options.deliveryMode = .automatic
         options.isNetworkAccessAllowed = true
@@ -106,14 +131,7 @@ class AssetPreviewViewController: UIViewController {
                 fatalError("failed to get AVAsset")
             }
             DispatchQueue.main.async {
-                let playerController = AVPlayerViewController()
-                let item = AVPlayerItem(asset: avAsset)
-                let player = AVPlayer(playerItem: item)
-                player.isMuted = true
-                player.play()
-                playerController.player = player
-                self.embedChild(playerController)
-                self.preferredContentSize = item.presentationSize
+                self.showVideo(asset: avAsset)
             }
         }
     }

Tusker/Screens/Compose/ComposeAttachmentsViewController.swift

@@ -265,6 +265,37 @@ class ComposeAttachmentsViewController: UITableViewController {
         }
     }
     
+    override func tableView(_ tableView: UITableView, contextMenuConfigurationForRowAt indexPath: IndexPath, point: CGPoint) -> UIContextMenuConfiguration? {
+        let attachment = attachments[indexPath.row]
+        // cast to NSIndexPath because identifier needs to conform to NSCopying
+        return UIContextMenuConfiguration(identifier: indexPath as NSIndexPath, previewProvider: { () -> UIViewController? in
+            return AssetPreviewViewController(attachment: attachment.data)
+        }) { (_) -> UIMenu? in
+            return nil
+        }
+    }
+    
+    private func targetedPreview(forConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
+        if let indexPath = (configuration.identifier as? NSIndexPath) as IndexPath?,
+            let cell = tableView.cellForRow(at: indexPath) as? ComposeAttachmentTableViewCell {
+            let parameters = UIPreviewParameters()
+            parameters.backgroundColor = .black
+            return UITargetedPreview(view: cell.assetImageView, parameters: parameters)
+        } else {
+            return nil
+        }
+    }
+    
+    override func tableView(_ tableView: UITableView, previewForHighlightingContextMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
+        return targetedPreview(forConfiguration: configuration)
+    }
+    
+    override func tableView(_ tableView: UITableView, previewForDismissingContextMenuWithConfiguration configuration: UIContextMenuConfiguration) -> UITargetedPreview? {
+        return targetedPreview(forConfiguration: configuration)
+    }
+
+    // MARK: Interaction
+    
     func addAttachmentPressed() {
         let sheetContainer = AssetPickerSheetContainerViewController()
         sheetContainer.assetPicker.assetPickerDelegate = self