add an interface to monitor the states of the polling connections

js/pacosako_io.js

@@ -16,8 +16,12 @@ const meta = {
    listeners: {},
    nextId: 1,
    currentRequest: null,
+   connectionState: 'initializing',
 };
 
+const stateListeners = {};
+const stateNextId = 1;
+
 /* One-time request, no caching or polling */
 function getGameState(gameId, retries) {
    if (arguments.length < 2) {
@@ -161,6 +165,70 @@ function sendUpdate(gameId, data, retries) {
    });
 }
 
+function onConnectionStateChanged(gameId, callback) {
+   if (arguments.length < 2) {
+      callback = gameId;
+      gameId = undefined;
+   }
+
+   if (gameId !== undefined) {
+      const original = callback;
+      callback = function(cbGameId, cbState) {
+         if (cbGameId === gameId) {
+            original(cbState);
+         }
+      };
+   }
+
+   const cbId = stateNextId;
+   stateNextId += 1;
+   stateListeners[cbId] = callback;
+
+   return function clearConnectionStateChanged() {
+      delete stateListeners[cbId];
+   };
+}
+
+function getConnectionState(gameId) {
+   if (arguments.length < 1) {
+      return meta.connectionState;
+   } else {
+      return games[gameId] && games[gameId].connectionState;
+   }
+}
+
+function setConnectionState(game, state) {
+   let gameId;
+
+   if (arguments.length < 2) {
+      gameId = 'meta';
+      state = game;
+      game = meta;
+   } else if (typeof game === 'string') {
+      gameId = game;
+      game = gamePollState(game);
+   } else {
+      gameId = game.gameId;
+   }
+
+   if (state !== game.connectionState) {
+      if (state !== 'initializing' && state !== 'connecting' && state !== 'polling'
+            && state !== 'failed' && state !== 'stopped') {
+         throw new TypeError(`invalid connection state: ${state}`);
+      }
+
+      game.connectionState = state;
+
+      for (const cbId in stateListeners) {
+         try {
+            stateListeners[cbId](gameId, state);
+         } catch(err) {
+            console.error('uncaught exception in callback', err);
+         }
+      }
+   }
+}
+
 function gamePollState(gameId) {
    if (gameId in games === false) {
       games[gameId] = {
@@ -168,6 +236,7 @@ function gamePollState(gameId) {
          data: { gameId, modified: 0 },
          listeners: [],
          nextId: 1,
+         connectionState: 'initializing',
       };
    }
 
@@ -177,15 +246,21 @@ function gamePollState(gameId) {
 function processGame(gameId, data) {
    const game = gamePollState(gameId);
 
-   if (data && data.modified > game.data.modified) {
+   if (data && (game.data.modified === 0 || data.modified > game.data.modified)) {
+      data.gameId = data.gameId || gameId;
       game.data = data;
+
       for (const cbId in game.listeners) {
          try {
-            game.listeners[cbId](data, gameId);
+            game.listeners[cbId](JSON.parse(JSON.stringify(data)), gameId);
          } catch(err) {
             console.error('uncaught exception in callback', err);
          }
       }
+
+      if (data.modified !== 0) {
+         processMeta({ games: [data], modified: 0 });
+      }
    }
 }
 
@@ -197,24 +272,31 @@ function startGamePoll(gameId, afterTime) {
          afterTime = game.data.modified;
       }
 
+      if (game.connectionState !== 'polling') {
+         if (game.connectionState !== 'failed') {
+            setConnectionState(game, 'connecting');
+         }
+      }
+
       const thisRequest = game.currentRequest = $.ajax({
          dataType: 'json',
          contentType: 'application/json',
-         url: `${API_BASE}/game/${gameId}/poll/${afterTime}`,
+         url: `${API_BASE}/game/${gameId}${!afterTime ? '' : `/poll/${afterTime}`}`,
          cache: false,
-         timeout: LONG_TIMEOUT,
+         timeout: afterTime ? LONG_TIMEOUT : SHORT_TIMEOUT,
       }).done((data, textStatus, jqXHR) => {
          if (game.currentRequest === thisRequest) {
             game.currentRequest = null;
-            if (jqXHR.status == 204) {
+            if (jqXHR.status !== 204) {
-               startGamePoll(gameId, afterTime);
+               afterTime = data.modified;
-            } else {
                processGame(gameId, data);
-               startGamePoll(gameId, data.modified);
             }
+            setConnectionState(game, 'polling');
+            startGamePoll(gameId, afterTime);
          }
       }).fail((jqXHR, textStatus, errorThrown) => {
          if (game.currentRequest === thisRequest) {
+            setConnectionState(game, 'failed');
             setTimeout(() => {
                if (game.currentRequest === thisRequest) {
                   game.currentRequest = null;
@@ -235,19 +317,28 @@ function stopGamePoll(gameId) {
    const request = game.currentRequest;
    if (request !== null) {
       game.currentRequest = null;
+      setConnectionState(game, 'stopped');
       request.abort();
    }
 }
 
 function processMeta(data) {
-   meta.lastModified = data.modified;
+   if (data.modified > meta.lastModified) {
+      meta.lastModified = data.modified;
+   }
 
    for (const game of data.games) {
-      if (game.gameId in meta.games === false || game.modified > meta.games[game.gameId].modified) {
+      const gameId = game.gameId;
-         meta.games[game.gameId] = game;
+      if (gameId in meta.games === false || game.modified > meta.games[gameId].modified) {
+         meta.games[gameId] = game;
+         if (gameId in games === false || games[gameId].data.modified === 0) {
+            const copy = Object.assign({}, game);
+            copy.modified = 0;
+            processGame(gameId, copy);
+         }
          for (const cbId in meta.listeners) {
             try {
-               meta.listeners[cbId](game, game.gameId);
+               meta.listeners[cbId](JSON.parse(JSON.stringify(game)), gameId);
             } catch(err) {
                console.error('uncaught exception in callback', err);
             }
@@ -262,24 +353,31 @@ function startMetaPoll(afterTime) {
          afterTime = meta.lastModified;
       }
 
+      if (meta.connectionState !== 'polling') {
+         if (meta.connectionState !== 'failed') {
+            setConnectionState('connecting');
+         }
+      }
+
       const thisRequest = meta.currentRequest = $.ajax({
          dataType: 'json',
          contentType: 'application/json',
-         url: `https://jessemcdonald.info/pacosako/api/games/poll/${afterTime}`,
+         url: `${API_BASE}/games${!afterTime ? '' : `/poll/${afterTime}`}`,
          cache: false,
-         timeout: LONG_TIMEOUT,
+         timeout: afterTime ? LONG_TIMEOUT : SHORT_TIMEOUT,
       }).done((data, textStatus, jqXHR) => {
          if (meta.currentRequest === thisRequest) {
             meta.currentRequest = null;
-            if (jqXHR.status == 204) {
+            if (jqXHR.status !== 204) {
-               startMetaPoll(afterTime);
+               afterTime = data.modified;
-            } else {
                processMeta(data);
-               startMetaPoll(data.modified);
             }
+            setConnectionState('polling');
+            startMetaPoll(afterTime);
          }
       }).fail((jqXHR, textStatus, errorThrown) => {
          if (meta.currentRequest === thisRequest) {
+            setConnectionState('failed');
             setTimeout(() => {
                if (meta.currentRequest === thisRequest) {
                   meta.currentRequest = null;
@@ -295,6 +393,7 @@ function stopMetaPoll() {
    const request = meta.currentRequest;
    if (request !== null) {
       meta.currentRequest = null;
+      setConnectionState('stopped');
       request.abort();
    }
 }
@@ -305,6 +404,8 @@ module.exports = {
    onGameUpdate,
    onMetaUpdate,
    sendUpdate,
+   getConnectionState,
+   onConnectionStateChanged,
 };
 
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