player.rs: Improve the fast-forward handling

Previously if you hit fast-forward but the offset remaining was
let that the amount you wanted to seek, it would do nothing.
Now it resets the stream and seekbar to the start.

Eventually this will just move on to the next episode in the
Queue once that's implemented.

podcasts-gtk/src/widgets/player.rs

@@ -553,21 +553,32 @@ impl PlayerExt for PlayerWidget {
 
     // Adapted from https://github.com/philn/glide/blob/b52a65d99daeab0b487f79a0e1ccfad0cd433e22/src/player_context.rs#L219-L245
     fn seek(&self, offset: ClockTime, direction: SeekDirection) {
+        // How far into the podcast we are
         let position = self.player.get_position();
         if position.is_none() || offset.is_none() {
             return;
         }
 
+        // How much podcast we have
         let duration = self.player.get_duration();
         let destination = match direction {
+            // If we are more than `offset` into the podcast, jump back that far
             SeekDirection::Backwards if position >= offset => Some(position - offset),
+            // If we haven't played `offset` yet just restart the podcast
             SeekDirection::Backwards if position < offset => Some(ClockTime::from_seconds(0)),
+            // If we have more than `offset` remaining jump forward they amount
             SeekDirection::Forward if !duration.is_none() && position + offset <= duration => {
                 Some(position + offset)
             }
+            // We don't have `offset` remaining just move to the end (ending playback)
+            SeekDirection::Forward if !duration.is_none() && position + offset > duration => {
+                Some(duration)
+            }
+            // Who knows what's going on ¯\_(ツ)_/¯
             _ => None,
         };
 
+        // If we calucated a new position, jump to it
         destination.map(|d| self.player.seek(d));
     }