cancel flow per design

Signal/src/ViewControllers/Photos/ImagePickerController.swift

@@ -8,6 +8,7 @@ import PromiseKit
 
 protocol ImagePickerGridControllerDelegate: AnyObject {
     func imagePickerDidCompleteSelection(_ imagePicker: ImagePickerGridController)
+    func imagePickerDidCancel(_ imagePicker: ImagePickerGridController)
 
     func imagePicker(_ imagePicker: ImagePickerGridController, isAssetSelected asset: PHAsset) -> Bool
     func imagePicker(_ imagePicker: ImagePickerGridController, didSelectAsset asset: PHAsset, attachmentPromise: Promise<SignalAttachment>)
@@ -273,7 +274,7 @@ class ImagePickerGridController: UICollectionViewController, PhotoLibraryDelegat
 
     @objc
     func didPressCancel(sender: UIBarButtonItem) {
-        self.dismiss(animated: true)
+        self.delegate?.imagePickerDidCancel(self)
     }
 
     // MARK: - Layout

Signal/src/ViewControllers/Photos/SendMediaNavigationController.swift

@@ -214,6 +214,31 @@ class SendMediaNavigationController: OWSNavigationController {
         pushViewController(approvalViewController, animated: true)
         updateButtons()
     }
+
+    private func didRequestExit(dontAbandonText: String) {
+        if attachmentDraftCollection.count == 0 {
+            self.sendMediaNavDelegate?.sendMediaNavDidCancel(self)
+        } else {
+            let alertTitle = NSLocalizedString("SEND_MEDIA_ABANDON_TITLE", comment: "alert title when user attempts to leave the send media flow when they have an in-progress album")
+
+            let alert = UIAlertController(title: alertTitle, message: nil, preferredStyle: .alert)
+
+            let confirmAbandonText = NSLocalizedString("SEND_MEDIA_CONFIRM_ABANDON_ALBUM", comment: "alert action, confirming the user wants to exit the media flow and abandon any photos they've taken")
+            let confirmAbandonAction = UIAlertAction(title: confirmAbandonText,
+                                                     style: .destructive,
+                                                     handler: { [weak self] _ in
+                                                        guard let self = self else { return }
+                                                        self.sendMediaNavDelegate?.sendMediaNavDidCancel(self)
+            })
+            alert.addAction(confirmAbandonAction)
+            let dontAbandonAction = UIAlertAction(title: dontAbandonText,
+                                                  style: .default,
+                                                  handler: { _ in  })
+            alert.addAction(dontAbandonAction)
+
+            self.presentAlert(alert)
+        }
+    }
 }
 
 extension SendMediaNavigationController: UINavigationControllerDelegate {
@@ -266,7 +291,8 @@ extension SendMediaNavigationController: PhotoCaptureViewControllerDelegate {
     }
 
     func photoCaptureViewControllerDidCancel(_ photoCaptureViewController: PhotoCaptureViewController) {
-        self.sendMediaNavDelegate?.sendMediaNavDidCancel(self)
+        let dontAbandonText = NSLocalizedString("SEND_MEDIA_RETURN_TO_CAMERA", comment: "alert action when the user decides not to cancel the media flow after all.")
+        didRequestExit(dontAbandonText: dontAbandonText)
     }
 }
 
@@ -276,6 +302,11 @@ extension SendMediaNavigationController: ImagePickerGridControllerDelegate {
         showApprovalAfterProcessingAnyMediaLibrarySelections()
     }
 
+    func imagePickerDidCancel(_ imagePicker: ImagePickerGridController) {
+        let dontAbandonText = NSLocalizedString("SEND_MEDIA_RETURN_TO_MEDIA_LIBRARY", comment: "alert action when the user decides not to cancel the media flow after all.")
+        didRequestExit(dontAbandonText: dontAbandonText)
+    }
+
     func showApprovalAfterProcessingAnyMediaLibrarySelections() {
         let mediaLibrarySelections: [MediaLibrarySelection] = self.mediaLibrarySelections.orderedValues
 

Signal/translations/en.lproj/Localizable.strings

@@ -1991,6 +1991,18 @@
 /* Text for button to send a Signal invite via SMS. %@ is placeholder for the recipient's phone number. */
 "SEND_INVITE_VIA_SMS_BUTTON_FORMAT" = "Invite via SMS: %@";
 
+/* alert title when user attempts to leave the send media flow when they have an in-progress album */
+"SEND_MEDIA_ABANDON_TITLE" = "Discard Media?";
+
+/* alert action, confirming the user wants to exit the media flow and abandon any photos they've taken */
+"SEND_MEDIA_CONFIRM_ABANDON_ALBUM" = "Discard Media";
+
+/* alert action when the user decides not to cancel the media flow after all. */
+"SEND_MEDIA_RETURN_TO_CAMERA" = "Return to Camera";
+
+/* alert action when the user decides not to cancel the media flow after all. */
+"SEND_MEDIA_RETURN_TO_MEDIA_LIBRARY" = "Return to Media Library";
+
 /* No comment provided by engineer. */
 "SEND_SMS_CONFIRM_TITLE" = "Invite a friend via insecure SMS?";