refactor: Pass bot messages by return value

* Bot.respondWhenPostback(), Bot.respondWhenImage(),
Bot.respondWhenText() now return the list of bot messages.
* DialogManager.executeClassificationResults() and
DialogManager.executeDialog() now return the list
of bot messages.
* DialogManager.execute() takes the previous bot messages
as its 3rd parameter.
* DialogManager.execute returns an object with keys
dialogs and botMessages.

BREAKING CHANGES:
* Dialog.execute() returns an object with keys action and
botMessage().

packages/botfuel-dialog/src/adapters/adapter.js

@@ -66,7 +66,15 @@ class Adapter {
   async handleMessage(userMessage) {
     logger.debug('handleMessage', userMessage);
     await this.addUserIfNecessary(userMessage.user);
-    return this.bot.handleMessage(this.extendMessage(userMessage));
+    const botMessages = await this.bot.handleMessage(this.extendMessage(userMessage));
+
+    for (const botMessage of botMessages) {
+      // TODO: Remove this ugly line
+      const extendedBotMessage = this.extendMessage(botMessage);
+
+      // eslint-disable-next-line no-await-in-loop
+      await this.sendMessage(extendedBotMessage);
+    }
   }
 
   /**

packages/botfuel-dialog/src/bot.js

@@ -152,16 +152,31 @@ class Bot {
    * @returns {Promise.<void>}
    */
   async handleMessage(userMessage) {
+    let botMessages = [];
+
     logger.debug('handleMessage', userMessage);
-    const context = {
+
+    const contextIn = {
       user: userMessage.user,
       brain: this.brain,
       userMessage,
       config: this.config,
     };
-    await this.middlewareManager.in(context, async () => {
-      await this.respond(userMessage);
+
+    await this.middlewareManager.in(contextIn, async () => {
+      botMessages = await this.respond(userMessage);
     });
+
+    const contextOut = {
+      user: userMessage.user,
+      brain: this.brain,
+      botMessages,
+      config: this.config,
+      userMessage,
+    };
+    await this.middlewareManager.out(contextOut, async () => {});
+
+    return botMessages;
   }
 
   /**
@@ -171,18 +186,23 @@ class Bot {
    * @returns {Promise.<void>}
    */
   async respond(userMessage) {
+    let botMessages;
+
     logger.debug('respond', userMessage);
+
     switch (userMessage.type) {
       case 'postback':
-        await this.respondWhenPostback(userMessage);
+        botMessages = await this.respondWhenPostback(userMessage);
         break;
       case 'image':
-        await this.respondWhenImage(userMessage);
+        botMessages = await this.respondWhenImage(userMessage);
         break;
       case 'text':
       default:
-        await this.respondWhenText(userMessage);
+        botMessages = await this.respondWhenText(userMessage);
     }
+
+    return botMessages;
   }
 
   /**
@@ -204,11 +224,12 @@ class Bot {
     });
 
     logger.debug('respondWhenText: classificationResults', classificationResults, messageEntities);
-    await this.dm.executeClassificationResults(
+    const botMessages = await this.dm.executeClassificationResults(
       userMessage,
       classificationResults,
       messageEntities,
     );
+    return botMessages;
   }
 
   /**
@@ -224,7 +245,8 @@ class Bot {
       name: userMessage.payload.value.dialog,
       data: { messageEntities: userMessage.payload.value.entities },
     };
-    await this.dm.executeDialog(userMessage, dialog);
+    const botMessages = await this.dm.executeDialog(userMessage, dialog);
+    return botMessages;
   }
 
   /**
@@ -240,34 +262,8 @@ class Bot {
       name: 'image',
       data: { url: userMessage.payload.value },
     };
-    await this.dm.executeDialog(userMessage, dialog);
-  }
-
-  /**
-   * Iterates over the bot messages and send them to adapter.
-   * @async
-   * @param {Object[]} botMessages - the bot messages
-   * @param {Object} userMessage - the user message
-   * @returns {Promise.<void>}
-   */
-  async send(botMessages, userMessage) {
-    logger.debug('send', botMessages);
-    const context = {
-      user: userMessage.user,
-      brain: this.brain,
-      botMessages,
-      config: this.config,
-      userMessage,
-    };
-    await this.middlewareManager.out(context, async () => {
-      for (const botMessage of botMessages) {
-        // TODO: Remove this ugly line
-        const extendedBotMessage = this.adapter.extendMessage(botMessage);
-
-        // eslint-disable-next-line no-await-in-loop
-        await this.adapter.sendMessage(extendedBotMessage);
-      }
-    });
+    const botMessages = await this.dm.executeDialog(userMessage, dialog);
+    return botMessages;
   }
 
   /**

packages/botfuel-dialog/src/dialog-manager.js

@@ -220,10 +220,15 @@ class DialogManager extends Resolver {
    * @param {Object[]} dialogs - the dialogs data
    * @returns {Promise.<Object[]>}
    */
-  async execute(userMessage, dialogs) {
+  async execute(userMessage, dialogs, previousBotMessages) {
+    let botMessages = previousBotMessages;
+
     logger.debug('execute', userMessage, dialogs);
     if (dialogs.stack.length === 0) {
-      return dialogs;
+      return {
+        dialogs,
+        botMessages,
+      };
     }
     const dialog = dialogs.stack[dialogs.stack.length - 1];
     if (dialog.blocked) {
@@ -239,15 +244,23 @@ class DialogManager extends Resolver {
         data: {},
       });
     } else {
-      const action = await this.resolve(dialog.name).execute(userMessage, dialog.data);
+      const { action, botMessages: newBotMessages } = await this.resolve(dialog.name).execute(
+        userMessage,
+        dialog.data,
+      );
+      botMessages = botMessages.concat(newBotMessages);
+
       logger.debug('execute: action', action);
       if (action.name !== Dialog.ACTION_WAIT) {
         dialogs = await this.applyAction(dialogs, action);
       } else {
-        return dialogs;
+        return {
+          dialogs,
+          botMessages,
+        };
       }
     }
-    return this.execute(userMessage, dialogs);
+    return this.execute(userMessage, dialogs, botMessages);
   }
 
   /**
@@ -262,7 +275,9 @@ class DialogManager extends Resolver {
     const userId = userMessage.user;
     const dialogs = await this.getDialogs(userId);
     this.updateWithClassificationResults(userId, dialogs, classificationResults, messageEntities);
-    await this.setDialogs(userId, await this.execute(userMessage, dialogs));
+    const { dialogs: newDialogs, botMessages } = await this.execute(userMessage, dialogs, []);
+    await this.setDialogs(userId, newDialogs);
+    return botMessages;
   }
 
   /**
@@ -276,7 +291,9 @@ class DialogManager extends Resolver {
     const userId = userMessage.user;
     const dialogs = await this.getDialogs(userId);
     this.updateWithDialog(dialogs, newDialog);
-    await this.setDialogs(userId, await this.execute(userMessage, dialogs));
+    const { dialogs: newDialogs, botMessages } = await this.execute(userMessage, dialogs, []);
+    await this.setDialogs(userId, newDialogs);
+    return botMessages;
   }
 }
 

packages/botfuel-dialog/tests/dialog-manager/dialog-manager.test.js

@@ -36,7 +36,7 @@ const classificationDisambiguationDialog = { name: 'classification-disambiguatio
 
 describe('DialogManager', () => {
   const bot = new Bot(TEST_CONFIG);
-  const { brain, dm, adapter } = bot;
+  const { brain, dm } = bot;
 
   beforeEach(async () => {
     await brain.clean();
@@ -52,8 +52,8 @@ describe('DialogManager', () => {
   });
 
   test('should not crash when no intent', async () => {
-    await dm.executeClassificationResults({ user: TEST_USER }, [], []);
-    expect(adapter.log).toEqual([new BotTextMessage('Not understood.').toJson(TEST_USER)]);
+    const botMessages = await dm.executeClassificationResults({ user: TEST_USER }, [], []);
+    expect(botMessages).toEqual([new BotTextMessage('Not understood.').toJson(TEST_USER)]);
   });
 
   test('should keep on the stack a dialog which is waiting', async () => {

packages/botfuel-dialog/tests/dialogs/classification-disambiguation-dialog.test.js

@@ -46,9 +46,11 @@ describe('ClassificationDisambiguationDialog', () => {
       }),
     ];
 
-    expect(
-      await dialog.execute({ user: 'TEST_USER' }, { classificationResults, messageEntities: [] }),
-    ).toEqual({
+    const { action } = await dialog.execute(
+      { user: 'TEST_USER' },
+      { classificationResults, messageEntities: [] },
+    );
+    expect(action).toEqual({
       name: ClassificationDisambiguationDialog.ACTION_COMPLETE,
     });
   });