[FIX] im_livechat: avoid useless message fetch when chat is created

When a live chat is created on the server, the `/mail/thread/messages`
route is called. This is not required since we know for a fact the
thread was just created. This PR prevent this useless request.

task-3646201

closes odoo/odoo#146785

Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/im_livechat/static/src/embed/common/@types/models.d.ts

@@ -2,5 +2,7 @@ declare module "models" {
     export interface Thread {
         chatbotTypingMessage: Message,
         livechatWelcomeMessage: Message,
+        chatbotScriptId: number | null,
+        isNewlyCreated: boolean,
     }
 }

addons/im_livechat/static/src/embed/common/disabled_features.js

@@ -26,7 +26,10 @@ patch(Thread.prototype, {
 
 patch(ThreadService.prototype, {
     async fetchNewMessages(thread) {
-        if (thread.type !== "livechat" || this.livechatService.state === SESSION_STATE.PERSISTED) {
+        if (
+            thread.type !== "livechat" ||
+            (this.livechatService.state === SESSION_STATE.PERSISTED && !thread.isNewlyCreated)
+        ) {
             return super.fetchNewMessages(...arguments);
         }
     },

addons/im_livechat/static/src/embed/common/livechat_service.js

@@ -184,6 +184,7 @@ export class LivechatService {
      */
     async getOrCreateThread({ persist = false } = {}) {
         let threadData = this.sessionCookie;
+        let isNewlyCreated = false;
         if (!threadData || (!threadData.uuid && persist)) {
             const chatbotScriptId = this.sessionCookie
                 ? this.sessionCookie.chatbot_script_id
@@ -199,6 +200,7 @@ export class LivechatService {
                 },
                 { shadow: true }
             );
+            isNewlyCreated = true;
         }
         if (!threadData?.operator_pid) {
             this.notificationService.add(_t("No available collaborator, please try again later."));
@@ -213,9 +215,10 @@ export class LivechatService {
         const thread = this.store.Thread.insert({
             ...threadData,
             id: threadData.id ?? this.TEMPORARY_ID,
-            isLoaded: !threadData.id,
+            isLoaded: !threadData.id || isNewlyCreated,
             model: "discuss.channel",
             type: "livechat",
+            isNewlyCreated,
         });
         this.state = thread.uuid ? SESSION_STATE.PERSISTED : SESSION_STATE.CREATED;
         if (this.state === SESSION_STATE.PERSISTED && !this.sessionInitialized) {

addons/im_livechat/static/src/embed/common/thread_model_patch.js

@@ -53,12 +53,16 @@ patch(Thread, {
 });
 
 patch(Thread.prototype, {
-    chatbotScriptId: null,
-
     setup() {
         super.setup();
         this.chatbotTypingMessage = Record.one("Message");
         this.livechatWelcomeMessage = Record.one("Message");
+        this.chatbotScriptId = null;
+        /**
+         * Indicates whether this thread was just created (i.e. no reload occurs
+         * since the creation).
+         */
+        this.isNewlyCreated = false;
     },
 
     get isLastMessageFromCustomer() {

addons/im_livechat/static/tests/embed/livechat_service_tests.js

@@ -6,8 +6,10 @@ import { loadDefaultConfig, start } from "@im_livechat/../tests/embed/helper/tes
 
 import { Command } from "@mail/../tests/helpers/command";
 
-import { click, contains } from "@web/../tests/utils";
 import { cookie } from "@web/core/browser/cookie";
+import { click, contains, insertText } from "@web/../tests/utils";
+import { triggerHotkey } from "@web/../tests/helpers/utils";
+import { Deferred } from "@web/core/utils/concurrency";
 
 QUnit.module("livechat service");
 
@@ -49,3 +51,38 @@ QUnit.test("previous operator prioritized", async () => {
     click(".o-livechat-LivechatButton");
     await contains(".o-mail-Message-author", { text: "John Doe" });
 });
+
+QUnit.test("Only necessary requests are made when creating a new chat", async (assert) => {
+    await startServer();
+    await loadDefaultConfig();
+    const linkPreviewDeferred = new Deferred();
+    await start({
+        mockRPC(route) {
+            if (!route.includes("assets")) {
+                assert.step(route);
+            }
+            if (route === "/mail/link_preview") {
+                linkPreviewDeferred.resolve();
+            }
+        },
+    });
+    await contains(".o-livechat-LivechatButton");
+    assert.verifySteps([
+        "/im_livechat/init",
+        "/web/webclient/load_menus", // called because menu_service is loaded in qunit bundle
+        "/mail/load_message_failures", // called because mail/core/web is loaded in qunit bundle
+    ]);
+    await click(".o-livechat-LivechatButton");
+    assert.verifySteps(["/im_livechat/get_session"]);
+    await insertText(".o-mail-Composer-input", "Hello!");
+    assert.verifySteps([]);
+    await triggerHotkey("Enter");
+    await contains(".o-mail-Message", { text: "Hello!" });
+    await linkPreviewDeferred;
+    assert.verifySteps([
+        "/im_livechat/get_session",
+        "/mail/init_messaging",
+        "/mail/message/post",
+        "/mail/link_preview",
+    ]);
+});