follow left wall

src/main.cc

@@ -17,6 +17,27 @@
 
 namespace asio = boost::asio;
 
+enum class Direction : int {
+  UP,
+  RIGHT,
+  DOWN,
+  LEFT,
+};
+
+std::string_view DirectionToString(Direction direction) {
+  switch (direction) {
+    case Direction::UP:
+      return "up";
+    case Direction::RIGHT:
+      return "right";
+    case Direction::DOWN:
+      return "down";
+    case Direction::LEFT:
+      return "left";
+  }
+  return "(invalid)";
+}
+
 class Bot {
   asio::any_io_executor executor;
   asio::ip::tcp::socket socket;
@@ -26,13 +47,7 @@ class Bot {
   int goal_x, goal_y;
   int x, y;
   bool up, right, down, left;
-
-  enum class Direction : int {
-    UP,
-    RIGHT,
-    DOWN,
-    LEFT,
-  };
+  Direction heading;
 
   asio::awaitable<void> Protocol();
   asio::awaitable<void> Join();
@@ -46,7 +61,11 @@ class Bot {
 
 Bot::Bot(asio::any_io_executor executor, std::string_view name,
          std::string_view pass)
-    : executor{executor}, socket{executor}, name{name}, pass{pass} {
+    : executor{executor},
+      socket{executor},
+      name{name},
+      pass{pass},
+      heading{Direction::LEFT} {
   asio::co_spawn(executor, std::bind(&Bot::Protocol, this), asio::detached);
 }
 
@@ -113,59 +132,30 @@ asio::awaitable<void> Bot::Join() {
 asio::awaitable<bool> Bot::Move(Direction direction) {
   asio::streambuf buf;
   std::ostream os{&buf};
-  std::string_view direction_str;
-  switch (direction) {
-    case Direction::LEFT:
-      direction_str = "left";
-      if (left) {
-        co_return false;
-      }
-      break;
-    case Direction::UP:
-      direction_str = "up";
-      if (up) {
-        co_return false;
-      }
-      break;
-    case Direction::RIGHT:
-      direction_str = "right";
-      if (right) {
-        co_return false;
-      }
-      break;
-    case Direction::DOWN:
-      direction_str = "down";
-      if (down) {
-        co_return false;
-      }
-      break;
+  if (direction == Direction::LEFT && left) {
+    co_return false;
   }
-  os << "move|" << direction_str << std::endl;
-  std::cout << "<- Go " << direction_str << std::endl;
+  if (direction == Direction::UP && up) {
+    co_return false;
+  }
+  if (direction == Direction::RIGHT && right) {
+    co_return false;
+  }
+  if (direction == Direction::DOWN && down) {
+    co_return false;
+  }
+  os << "move|" << DirectionToString(direction) << std::endl;
+  std::cout << "<- Go " << DirectionToString(direction) << std::endl;
   co_await async_write(socket, buf.data(), asio::use_awaitable);
   co_return true;
 }
 
 asio::awaitable<void> Bot::ChooseMove() {
-  // move closer to the goal if possible
-  if (x > goal_x && co_await Move(Direction::LEFT)) {
-    co_return;
+  // follow left wall
+  while (!co_await Move(heading)) {
+    heading = Direction{(static_cast<int>(heading) + 1) % 4};
   }
-  if (x > goal_y && co_await Move(Direction::UP)) {
-    co_return;
-  }
-  if (x < goal_x && co_await Move(Direction::RIGHT)) {
-    co_return;
-  }
-  if (x < goal_y && co_await Move(Direction::DOWN)) {
-    co_return;
-  }
-
-  // choose a random direction
-  std::uniform_int_distribution<int> direction{0, 3};
-  while (!co_await Move(Direction{direction(generator)}))
-    ;
-
+  heading = Direction{(static_cast<int>(heading) + 3) % 4};
   co_return;
 }