Implement make_move function on engine

rs/src/ui.rs

@@ -120,6 +120,21 @@ impl Ui {
             }
         }
     }
+    fn make_move(&mut self, args: &[&str]) -> Result<String, String> {
+        if args.len() != 2 {
+            return Err("make_move takes 2 args".to_owned());
+        };
+        let source = board::Position::parse(args[0])
+            .map_err(|_| format!("Error parsing source {}", args[0]))?;
+        let target = board::Position::parse(args[1])
+            .map_err(|_| format!("Error parsing target {}", args[1]))?;
+        match self.board.make_move(&source, target) {
+            Err(()) => {
+                Err(format!("Move not possible {}-{}", args[0], args[1]))
+            }
+            Ok(()) => Ok(self.board.to_string()),
+        }
+    }
     fn handle_command(&mut self, s: &str) -> Result<String, String> {
         let mut cmd = s.split(',');
         // There will be at least an empty string => otherwise panic
@@ -128,6 +143,7 @@ impl Ui {
         match cmd_type {
             "get_state" => self.get_state(&args),
             "get_moves" => self.get_moves(&args),
+            "make_move" => self.make_move(&args),
             "" => Err("No command given".to_owned()),
             _ => Err("Invalid command".to_owned()),
         }