Add buttons to next video and restart video (fix #106)

Previous video requires rebuilding queue a little, maybe in the future

Model/Player/PlayerModel.swift

@@ -281,8 +281,12 @@ final class PlayerModel: ObservableObject {
     }
 
     func upgradeToStream(_ stream: Stream, force: Bool = false) {
+        guard let video = currentVideo else {
+            return
+        }
+
         if !self.stream.isNil, force || self.stream != stream {
-            playStream(stream, of: currentVideo!, preservingTime: true, upgrading: true)
+            playStream(stream, of: video, preservingTime: true, upgrading: true)
         }
     }
 

Model/Watch.swift

@@ -1,10 +1,12 @@
 import CoreData
+import CoreMedia
 import Defaults
 import Foundation
 
 @objc(Watch)
 final class Watch: NSManagedObject, Identifiable {
     @Default(.watchedThreshold) private var watchedThreshold
+    @Default(.saveHistory) private var saveHistory
 }
 
 extension Watch {
@@ -45,4 +47,15 @@ extension Watch {
         formatter.unitsStyle = .full
         return formatter.localizedString(for: watchedAt, relativeTo: Date())
     }
+
+    var timeToRestart: CMTime? {
+        finished ? nil : saveHistory ? .secondsInDefaultTimescale(stoppedAt) : nil
+    }
+
+    var video: Video {
+        Video(
+            videoID: videoID, title: "", author: "",
+            length: 0, published: "", views: -1, channel: Channel(id: "", name: "")
+        )
+    }
 }