Merge pull request #42 from tobyspark/feature-purgeable-video-files

Feature: Move video file to purgeable storage once uploaded

To minimise iCloud backup size and low-storage scenarios, the video file will be moved to the cache folder when upload is complete. If the system then culls the video file from the cache folder, a bundled-with-the-app placeholder video will be shown instead.

ORBIT Camera/DetailViewController.swift

@@ -596,27 +596,20 @@ class DetailViewController: UIViewController {
                     os_log("Could not get video for re-record recordStart", log: appUILog)
                     return
                 }
-                do {
-                    try FileManager.default.removeItem(at: video.url)
-                } catch {
-                    os_log("Could not delete previous recording to re-record", log: appUILog)
-                    return
-                }
 
                 // Go, configuring completion handler that updates the UI
+                let url = Video.mintRecordURL()
                 let videoPageIndex = pageIndex
-                camera.recordStart(to: video.url) { [weak self] in
+                camera.recordStart(to: url) { [weak self] in
                     guard let self = self
                     else { return }
 
                     // Update controller state
                     self.rerecordPageIndexes.remove(videoPageIndex)
 
-                    // Delete server record
-                    video.deleteUpload()
-                    video.orbitID = nil
-
                     // Update record
+                    video.rerecordReset()
+                    video.url = url
                     video.recorded = Date()
                     try! dbQueue.write { db in try video.save(db) }
 
@@ -628,16 +621,9 @@ class DetailViewController: UIViewController {
                     os_log("No thing on recordStart", log: appUILog)
                     return
                 }
-                guard let url = try? FileManager.default
-                        .url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
-                        .appendingPathComponent(NSUUID().uuidString)
-                        .appendingPathExtension("mov")
-                else {
-                    os_log("Could not create URL for recordStart", log: appUILog)
-                    return
-                }
 
                 // Go, setting completion handler that creates a Video record and updates the UI
+                let url = Video.mintRecordURL()
                 let kind = videoKind(description: videoPageControl.currentCategoryName!)
                 camera.recordStart(to: url) {
                     // Create a Video record

ORBIT Camera/Video.swift

@@ -19,18 +19,38 @@ struct Video: Codable, Equatable {
     var thingID: Int64?
 
     /// On-device file URL of a video the participant has recorded
-    /// As the app's data folder is named dynamically, only store the filename and get/set the URL relative to a type set storage location
+    /// To minimise iCloud backup size and low-storage scenarios, the video file will be moved to the cache folder when upload is complete.
+    /// If the system then culls the video file from the cache folder, a bundled-with-the-app placeholder video URL will be returned instead.
+    /// Plus, as the app's data folder is named dynamically, only store the filename and get/set the URL relative to a type set storage location
     var url: URL {
-        get { URL(fileURLWithPath: filename, relativeTo: Video.storageURL) }
-        set { filename = newValue.lastPathComponent }
+        get {
+            var url = URL(fileURLWithPath: filename, relativeTo: Video.storageURL)
+            do {
+                try _ = url.checkResourceIsReachable()
+                return url
+            }
+            catch {}
+            url = URL(fileURLWithPath: filename, relativeTo: Video.storageCacheURL)
+            do {
+                try _ = url.checkResourceIsReachable()
+                return url
+            }
+            catch {}
+            return Video.placeholderURL
+        }
+        set {
+            filename = newValue.lastPathComponent
+        }
     }
 
     /// When the video was recorded
     var recorded: Date
 
     /// A unique ID for the thing in the ORBIT dataset (or rather, the database the dataset will be produced from)
     // Note this was handled more elegantly by orbitID being an UploadStatus enum, but the supporting code was getting ridiculous.
-    var orbitID: Int?
+    var orbitID: Int? {
+        didSet { if oldValue == nil && orbitID != nil { moveToCacheStorage() } }
+    }
 
     /// The kind of video this is.
     /// Current terminology: videos are taken with one of two goals: "train" or "test", with two "techniques" used for test videos: "zoom" and "pan".
@@ -96,33 +116,57 @@ struct Video: Codable, Equatable {
         self.url = url
     }
 
-    // Private property backing `url`
-    private var filename: String
-
-    // Private type property backing `url`
-    private static var storageURL: URL {
-        try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true) // FIXME: try!
-    }
-
-    // Private type property backing `url`
-    private static var storageCacheURL: URL {
-        try! FileManager.default.url(for: .cachesDirectory, in: .userDomainMask, appropriateFor: nil, create: true) // FIXME: try!
+    /// Reset in preparation for a new video URL to be set. Deletes the file, deletes the server record, resets statuses pertaining to previous video
+    mutating func rerecordReset() {
+        // Cancel any in-progress upload
+        cancelUploading()
+
+        // Delete video from server
+        deleteUpload()
+
+        // Remove file
+        for url in [URL(fileURLWithPath: filename, relativeTo: Video.storageURL), URL(fileURLWithPath: filename, relativeTo: Video.storageURL)] {
+            do {
+                try FileManager.default.removeItem(at: url)
+                break
+            } catch {}
+        }
+
+        // Reset statuses
+        verified = .unvalidated
+        orbitID = nil
     }
 
-    private static var placeholderURL: URL {
-        Bundle.main.url(forResource: "orbit-cup-photoreal", withExtension: "mp4")! // FIXME: !
+    /// Generate a URL suitable for recording a video and then setting this URL as the video's property
+    static func mintRecordURL() -> URL {
+        Video.storageURL
+            .appendingPathComponent(NSUUID().uuidString)
+            .appendingPathExtension("mov")
     }
+
+    // Private property backing `url`
+    private var filename: String
 
+    // Private method backing `url`
     private func moveToCacheStorage() {
         do {
             try FileManager.default.moveItem(
                 at: URL(fileURLWithPath: filename, relativeTo: Video.storageURL),
                 to: URL(fileURLWithPath: filename, relativeTo: Video.storageCacheURL)
             )
         } catch {
-            print(error)
+            os_log("Move of %{public}s file to cache failed", self.description)
         }
     }
+
+    // Private type property backing `url`
+    private static let storageURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true) // FIXME: try!
+
+    // Private type property backing `url`
+    private static let storageCacheURL = try! FileManager.default.url(for: .cachesDirectory, in: .userDomainMask, appropriateFor: nil, create: true) // FIXME: try!
+
+    // Private type property backing `url`
+    private static let placeholderURL = Bundle.main.url(forResource: "orbit-cup-photoreal", withExtension: "mp4")! // FIXME: !
 }
 
 extension Video: FetchableRecord, MutablePersistableRecord {
@@ -152,7 +196,14 @@ extension Video: FetchableRecord, MutablePersistableRecord {
         deleteUpload()
 
         // Remove file
-        try FileManager.default.removeItem(at: url)
+        for url in [URL(fileURLWithPath: filename, relativeTo: Video.storageURL), URL(fileURLWithPath: filename, relativeTo: Video.storageURL)] {
+            do {
+                try FileManager.default.removeItem(at: url)
+                break
+            } catch {}
+        }
+
+        // Delete record
         let deleted = try performDelete(db)
         if !deleted { os_log("Failed to delete Video") }
         return deleted