add place_robot + tests, changed coordinate calculation, fixed borrowing issues

src/main.rs

@@ -31,8 +31,8 @@ impl World {
         self.map = vec!['.'; (self.x * self.y) as usize];
     }
     /// Set robot on the map.
-    fn set_robot(&mut self, r: Robot) {
+    fn set_robot(&mut self, r: &Robot) {
-        self.map[(r.p.x * r.p.y) as usize] = match r.o {
+        self.map[(r.p.x + (r.p.y * self.x as i32)) as usize] = match r.o {
             Orientation::N => '↑',
             Orientation::S => '↓',
             Orientation::E => '→',
@@ -40,8 +40,15 @@ impl World {
         }
     }
     /// Check if a position is free.
-    fn empty_position(&mut self, p: Position) -> bool {
+    fn empty_position(&mut self, p: &Position) -> bool {
-        self.map[(p.x * p.y) as usize] == '.'
+        self.map[(p.x + (p.y * self.x as i32)) as usize] == '.'
+    }
+    /// Place robot on the map after checking if the position is valid.
+    fn place_robot(&mut self, r: &Robot) -> Result<(), String> {
+        match r.p.is_valid(&self) {
+            Ok(_) => Ok(self.set_robot(r)),
+            Err(e) => Err(e),
+        }
     }
 }
 
@@ -53,7 +60,7 @@ struct Position {
 
 impl Position {
     /// Check if position is in the map.
-    fn is_valid(self, w: World) -> Result<(), String> {
+    fn is_valid(&self, w: &World) -> Result<(), String> {
         if (self.x, self.y) > (0, 0) && (self.x, self.y) < (w.x as i32, w.y as i32) {
             Ok(())
         } else {
@@ -93,7 +100,8 @@ impl Robot {
         self.q = q;
     }
     /// Apply forward instruction to the robot.
-    fn move_forward(&mut self) {
+    fn move_forward(&mut self, w: &mut World) {
+        w.map[(self.p.x + (self.p.y * w.x as i32)) as usize] = '.';
         match self.o {
             Orientation::N => self.p.y -= 1,
             Orientation::S => self.p.y += 1,
@@ -279,7 +287,7 @@ mod tests {
             map: Vec::new(),
         };
         w.create();
-        w.set_robot(r);
+        w.set_robot(&r);
         assert_eq!(w.map, vec!['↑', '.', '.', '.']);
     }
 
@@ -291,7 +299,13 @@ mod tests {
             p: Position { x: 1, y: 1 },
             q: Queue::new(),
         };
-        r.move_forward();
+        let mut w: World = World {
+            x: 2,
+            y: 2,
+            map: Vec::new(),
+        };
+        w.create();
+        r.move_forward(&mut w);
         assert_eq!(0, r.p.y);
         r.move_right();
         assert_eq!(2, r.p.x);
@@ -299,6 +313,48 @@ mod tests {
         assert_eq!(1, r.p.x);
     }
 
+    #[test]
+    fn test_place_robot() {
+        let mut r: Robot = Robot {
+            id: 0,
+            o: Orientation::N,
+            p: Position { x: 1, y: 1 },
+            q: Queue::new(),
+        };
+        let mut w: World = World {
+            x: 2,
+            y: 2,
+            map: Vec::new(),
+        };
+        w.create();
+        w.set_robot(&r);
+        assert_eq!(w.map, vec!['.', '.', '.', '↑']);
+        r.move_forward(&mut w);
+        assert!(w.place_robot(&r).is_ok());
+        assert_eq!(w.map, vec!['.', '↑', '.', '.']);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_place_robot_fail() {
+        let mut r: Robot = Robot {
+            id: 0,
+            o: Orientation::N,
+            p: Position { x: 1, y: 1 },
+            q: Queue::new(),
+        };
+        let mut w: World = World {
+            x: 2,
+            y: 2,
+            map: Vec::new(),
+        };
+        w.create();
+        w.set_robot(&r);
+        r.move_forward(&mut w);
+        r.move_forward(&mut w);
+        assert!(w.place_robot(&r).is_ok());
+    }
+
     #[test]
     fn test_empty_position() {
         let mut w: World = World {
@@ -307,7 +363,7 @@ mod tests {
             map: Vec::new(),
         };
         w.create();
-        assert!(w.empty_position(Position { x: 0, y: 0 }));
+        assert!(w.empty_position(&Position { x: 0, y: 0 }));
     }
 
     #[test]
@@ -318,7 +374,7 @@ mod tests {
             y: 5,
             map: Vec::new(),
         };
-        assert!(p.is_valid(w).is_ok());
+        assert!(p.is_valid(&w).is_ok());
     }
 
     #[test]
@@ -330,6 +386,6 @@ mod tests {
             y: 5,
             map: Vec::new(),
         };
-        assert!(p.is_valid(w).is_ok());
+        assert!(p.is_valid(&w).is_ok());
     }
 }