From 173182f8e76242c275b159f5bb555c7fddc6cc5d Mon Sep 17 00:00:00 2001
From: Thomas Lindner <tom@dl6tom.de>
Date: Fri, 20 May 2022 18:55:22 +0200
Subject: [PATCH] auto-reconnect and don't drop messages

---
 src/main.cc | 99 ++++++++++++++++++++++++++++++++---------------------
 1 file changed, 60 insertions(+), 39 deletions(-)

diff --git a/src/main.cc b/src/main.cc
index 7a9c7e2..68afe81 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -6,11 +6,13 @@
 #include <boost/asio/io_context.hpp>
 #include <boost/asio/ip/tcp.hpp>
 #include <boost/asio/read_until.hpp>
+#include <boost/asio/steady_timer.hpp>
 #include <boost/asio/streambuf.hpp>
 #include <boost/asio/use_awaitable.hpp>
 #include <boost/asio/write.hpp>
 #include <iostream>
 #include <random>
+#include <sstream>
 #include <string>
 #include <string_view>
 #include <utility>
@@ -40,6 +42,7 @@ std::string_view DirectionToString(Direction direction) {
 
 class Bot {
   asio::any_io_executor executor;
+  asio::steady_timer timer;
   asio::ip::tcp::socket socket;
   std::string name;
   std::string pass;
@@ -62,6 +65,7 @@ class Bot {
 Bot::Bot(asio::any_io_executor executor, std::string_view name,
          std::string_view pass)
     : executor{executor},
+      timer{executor},
       socket{executor},
       name{name},
       pass{pass},
@@ -72,49 +76,66 @@ Bot::Bot(asio::any_io_executor executor, std::string_view name,
 asio::awaitable<void> Bot::Protocol() {
   asio::ip::tcp::resolver resolver{executor};
   asio::ip::tcp::resolver::query query{"94.45.241.27", "4000"};
-
-  co_await asio::async_connect(
-      socket, co_await resolver.async_resolve(query, asio::use_awaitable),
-      asio::use_awaitable);
+  auto host = co_await resolver.async_resolve(query, asio::use_awaitable);
 
   while (true) {
-    asio::streambuf buf;
-    buf.commit(co_await asio::async_read_until(socket, buf, '\n',
-                                               asio::use_awaitable));
-    std::istream is{&buf};
-    std::string field;
-    char dummy;
-    std::getline(is, field, '|');
-    if (field == "motd") {
-      std::getline(is, field);
-      std::cout << "-> MotD: " << field << std::endl;
-      co_await Join();
-    } else if (field == "error") {
-      std::getline(is, field);
-      std::cout << "-> Error: " << field << std::endl;
-      co_return;
-    } else if (field == "goal") {
-      is >> goal_x >> dummy >> goal_y;
-      std::cout << "-> Goal is at (" << goal_x << ", " << goal_y << ")"
-                << std::endl;
-    } else if (field == "pos") {
-      is >> x >> dummy >> y >> dummy >> up >> dummy >> right >> dummy >> down >>
-          dummy >> left;
-      std::cout << "-> Position at (" << x << ", " << y << ")" << std::endl;
+    while (true) {
+      try {
+        co_await asio::async_connect(socket, host, asio::use_awaitable);
+        break;
+      } catch (std::exception &e) {
+        std::cout << e.what() << std::endl;
+      }
+      timer.expires_after(std::chrono::seconds(1));
+      co_await timer.async_wait(asio::use_awaitable);
+    }
+
+    try {
+      while (true) {
+        asio::streambuf buf;
+        co_await asio::async_read_until(socket, buf, '\n', asio::use_awaitable);
+        std::istream is{&buf};
+        std::string line;
+        while (std::getline(is, line)) {
+          std::istringstream iss{line};
+          std::string field;
+          char dummy;
+          std::getline(iss, field, '|');
+          if (field == "motd") {
+            std::getline(iss, field);
+            std::cout << "-> MotD: " << field << std::endl;
+            co_await Join();
+          } else if (field == "error") {
+            std::getline(iss, field);
+            std::cout << "-> Error: " << field << std::endl;
+          } else if (field == "goal") {
+            iss >> goal_x >> dummy >> goal_y;
+            std::cout << "-> Goal is at (" << goal_x << ", " << goal_y << ")"
+                      << std::endl;
+          } else if (field == "pos") {
+            iss >> x >> dummy >> y >> dummy >> up >> dummy >> right >> dummy >>
+                down >> dummy >> left;
+            std::cout << "-> Position at (" << x << ", " << y << ")"
+                      << std::endl;
 #define X(b) (b ? #b ", " : "")
-      std::cout << "   Walls are " << X(up) << X(right) << X(down) << X(left)
-                << std::endl;
+            std::cout << "   Walls are (" << X(up) << X(right) << X(down)
+                      << X(left) << ")" << std::endl;
 #undef X
-      co_await ChooseMove();
-    } else if (field == "win" || field == "lose") {
-      int win, lose;
-      is >> win >> dummy >> lose;
-      std::cout << "-> You " << field << '!' << std::endl;
-      std::cout << "   Score: " << win << '/' << lose << std::endl;
-    } else {
-      std::cout << "unhandled message: " << field << '|';
-      std::getline(is, field);
-      std::cout << field << std::endl;
+            co_await ChooseMove();
+          } else if (field == "win" || field == "lose") {
+            int win, lose;
+            iss >> win >> dummy >> lose;
+            std::cout << "-> You " << field << '!' << std::endl;
+            std::cout << "   Score: " << win << '/' << lose << std::endl;
+          } else {
+            std::cout << "unhandled message: " << field << '|';
+            std::getline(iss, field);
+            std::cout << field << std::endl;
+          }
+        }
+      }
+    } catch (std::exception &e) {
+      std::cout << e.what() << std::endl;
     }
   }
   co_return;