Handle WS reconnection in messaging module

www/messaging.js

@@ -1,15 +1,25 @@
 function Messaging(modules) {
-  var ws = new WebSocket(window.location.origin.replace(/^http/, 'ws') + '/play/');
+  var wsLocation = window.location.origin.replace(/^http/, 'ws') + '/play/';
+  var ws;
   var debug = getParameters().debug;
   var doLog = debug != undefined && debug.match(/^(?:1|t(?:rue)?|v(?:rai)?)$/i);
-  var keepAlivePeriod = 20000;
+  var on = false;
+  var s = 1000; /* ms */
+  var keepAlivePeriod = 20;
+  var reconnectDelay = 1;
   var routes = {callbacks: [], children: {}};
+  var wsHandlers = {
+    open: [function() {on = true; reconnectDelay = 1}, ping],
+    close: [function() {on = false;}, reconnect]
+  };
+
+  init();
 
   return {
     addEventListener: addEventListener,
-    send: send,
-    start: start
-  }
+    isOn: isOn,
+    send: send
+  };
 
   function get(obj, path, write) {
     write = write || false;
@@ -37,8 +47,16 @@ function Messaging(modules) {
   }
 
   function addEventListener(path, callback) {
-    var route = get(routes, path, true);
-    route.callbacks.push(callback);
+    if(Array.isArray(path)) {
+      var route = get(routes, path, true);
+      route.callbacks.push(callback);
+    } else {
+      if(wsHandlers[path] != undefined) {
+        wsHandlers[path].push(callback);
+      } else {
+        log('Unsupported websocket event "' + path + '"');
+      }
+    }
   }
 
   function messageListener(event) {
@@ -59,26 +77,51 @@ function Messaging(modules) {
     log(o);
   };
 
-  function log(message) {
-    if(doLog) {
-      console.log(message);
-    }
-  }
-
-  function start() {
-    ws.addEventListener('message', messageListener);
-    ws.addEventListener('open', ping);
-    addEventListener(["Pong"], ping);
-    addEventListener(["Error"], function(o) {modules.screen.error(o.error);});
-  }
-
   function send(o) {
     ws.send(JSON.stringify(o));
     o.direction = 'client > server';
     log(o);
   }
 
+  function log(message) {
+    if(doLog) {
+      console.log(message);
+    }
+  }
+
+  function init() {
+    connect();
+    addEventListener(["Pong"], ping);
+    addEventListener(["Error"], function(o) {modules.screen.error(o.error);});
+  }
+
+  function connect() {
+    ws = new WebSocket(window.location.origin.replace(/^http/, 'ws') + '/play/');
+    ws.addEventListener('message', messageListener);
+    ws.addEventListener('open', function(e) {
+      wsHandlers.open.forEach(function(handler) {handler(e);});
+    });
+    ws.addEventListener('close', function(e) {
+      wsHandlers.close.forEach(function(handler) {handler(e);});
+    });
+  }
+
+  function reconnect() {
+    setTimeout(connect, reconnectDelay * s);
+    if(reconnectDelay < 16) {
+      reconnectDelay *= 2;
+    }
+  }
+
+  function isOn() {
+    return on;
+  }
+
   function ping() {
-    setTimeout(function() {send({tag: "Ping"});}, keepAlivePeriod);
+    setTimeout(function() {
+      if(isOn()) {
+        send({tag: "Ping"});
+      }
+    }, keepAlivePeriod * s);
   }
 }