Cleanup draft attachment loading and handle missing attachments

#4

Tusker/Screens/Compose/ComposeViewController.swift

@@ -580,21 +580,42 @@ extension ComposeViewController: DraftsTableViewControllerDelegate {
         updatePlaceholder()
         updateCharactersRemaining()
         
+
         let result = PHAsset.fetchAssets(withLocalIdentifiers: draft.attachments.map { $0.assetIdentifier }, options: nil)
-        self.selectedAssets = []
-        var i = 0
-        while i < result.count {
-            selectedAssets.append(result[i])
-            i += 1
+        var assets = [String: (asset: PHAsset, description: String)]()
+        var addedAssets = 0
+        while addedAssets < result.count {
+            let asset = result[addedAssets]
+            let attachment = draft.attachments.first(where: { $0.assetIdentifier == asset.localIdentifier })!
+            assets[asset.localIdentifier] = (asset, attachment.description)
+            addedAssets += 1
         }
+
+        self.selectedAssets = assets.values.map { $0.asset }
         updateAttachmentViews()
         
-        var j = 0
-        for subview in attachmentsStackView.arrangedSubviews {
-            guard let mediaView = subview as? ComposeMediaView else { continue }
-            mediaView.descriptionTextView.text = draft.attachments[j].description
+        for case let mediaView as ComposeMediaView in attachmentsStackView.arrangedSubviews {
+            let attachment = draft.attachments.first(where: { $0.assetIdentifier == mediaView.assetIdentifier })!
+            mediaView.descriptionTextView.text = attachment.description
+            
+            // call the delegate method manually, since setting the text property doesn't call it
             mediaView.textViewDidChange(mediaView.descriptionTextView)
-            j += 1
+        }
+    }
+    
+    func draftSelectionCompleted() {
+        // check that all the assets from the draft have been added
+        if let currentDraft = currentDraft, selectedAssets.count < currentDraft.attachments.count {
+            // some of the assets in the draft weren't loaded, so notify the user
+            
+            let difference = currentDraft.attachments.count - selectedAssets.count
+            // todo: localize me
+            let suffix = difference == 1 ? "" : "s"
+            let verb = difference == 1 ? "was" : "were"
+            let alertController = UIAlertController(title: "Missing Attachments", message: "\(difference) attachment\(suffix) \(verb) removed from the Photos Library and could not be loaded.", preferredStyle: .alert)
+            alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
+            
+            present(alertController, animated: true)
         }
     }
 }

Tusker/Screens/Compose/Drafts/DraftsTableViewController.swift

@@ -11,6 +11,7 @@ import UIKit
 protocol DraftsTableViewControllerDelegate {
     func draftSelectionCanceled()
     func draftSelected(_ draft: DraftsManager.Draft)
+    func draftSelectionCompleted()
 }
 
 class DraftsTableViewController: UITableViewController {
@@ -61,7 +62,9 @@ class DraftsTableViewController: UITableViewController {
     
     override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
         delegate?.draftSelected(draft(for: indexPath))
-        dismiss(animated: true)
+        dismiss(animated: true) {
+            self.delegate?.draftSelectionCompleted()
+        }
     }
     
     override func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {

Tusker/Views/Compose Media/ComposeMediaView.swift

@@ -21,6 +21,8 @@ class ComposeMediaView: UIView {
     @IBOutlet weak var descriptionTextView: UITextView!
     @IBOutlet weak var placeholderLabel: UILabel!
     
+    var assetIdentifier: String?
+    
     static func create() -> ComposeMediaView {
         return UINib(nibName: "ComposeMediaView", bundle: nil).instantiate(withOwner: nil, options: nil).first as! ComposeMediaView
     }
@@ -35,7 +37,8 @@ class ComposeMediaView: UIView {
     }
     
     func update(asset: PHAsset) {
-//        let size = imageView.frame.size // is this initialized yet?
+        self.assetIdentifier = asset.localIdentifier
+        
         let size = CGSize(width: 80, height: 80)
         PHImageManager.default().requestImage(for: asset, targetSize: size, contentMode: .aspectFill, options: nil) { (image, _) in
             self.imageView.image = image