Add the ability to pause singleplayer matches (#68)

Reviewed-on: #68
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/netcode/session.rs

@@ -42,6 +42,15 @@ pub enum SessionConfigError {
 }
 
 impl SessionConfig {
+    /// Returns whether this match has more than one remote participant.
+    pub fn is_multiplayer(&self) -> bool {
+        self.players.len() > 1
+            || self
+                .players
+                .iter()
+                .any(|player| matches!(player, PlayerConnection::Remote(_)))
+    }
+
     pub fn from_args(args: &Args, player_count: usize) -> Result<Self, SessionConfigError> {
         if player_count == 0 {
             return Err(SessionConfigError::NoPlayers);
@@ -196,6 +205,13 @@ mod tests {
             config.players,
             [PlayerConnection::Local, PlayerConnection::Local]
         );
+        assert!(config.is_multiplayer());
+    }
+
+    #[test]
+    fn single_local_player_is_not_multiplayer() {
+        let config = SessionConfig::from_args(&args(&["game", "--players", "1"]), 1).unwrap();
+        assert!(!config.is_multiplayer());
     }
 
     #[test]
@@ -207,6 +223,7 @@ mod tests {
         .unwrap();
         assert!(matches!(config.players[0], PlayerConnection::Local));
         assert!(matches!(config.players[1], PlayerConnection::Remote(_)));
+        assert!(config.is_multiplayer());
     }
 
     #[test]