From c1a26fd9ebd601417fbfe975bf148485384c6475 Mon Sep 17 00:00:00 2001
From: LASER-Yi <liangyi0007@gmail.com>
Date: Sat, 19 Mar 2022 11:54:24 +0800
Subject: Fix issues when trying to create background tasks

---
 frontend/src/modules/task/index.ts     | 22 +++++++++++++++-------
 frontend/src/modules/task/task.d.ts    |  6 +++---
 frontend/src/modules/task/utilities.ts | 14 +++++++++++---
 3 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/frontend/src/modules/task/index.ts b/frontend/src/modules/task/index.ts
index 6ca47341f..8580ca05c 100644
--- a/frontend/src/modules/task/index.ts
+++ b/frontend/src/modules/task/index.ts
@@ -9,7 +9,7 @@ class TaskManager {
   private onBeforeUnload(e: BeforeUnloadEvent) {
     const message = "Background tasks are still running";
 
-    if (this.tasks.some((t) => t.status !== "success")) {
+    if (this.tasks.some((t) => t.status === "running")) {
       e.preventDefault();
       e.returnValue = message;
       return;
@@ -17,22 +17,29 @@ class TaskManager {
     delete e["returnValue"];
   }
 
-  private generateUniqueId(): string {
-    return "TODO-TODO";
+  private findTask(ref: Task.TaskRef): Task.Callable | undefined {
+    return this.tasks.find((t) => t.id === ref.callableId);
   }
 
-  create<T extends Task.AnyCallable>(fn: T, parameters: Parameters<T>): string {
-    const newTask = fn as Task.Callable<T>;
+  create<T extends Task.AnyCallable>(fn: T, parameters: Parameters<T>): symbol {
+    // Clone this function
+    const newTask = fn.bind({}) as Task.Callable<T>;
     newTask.status = "idle";
     newTask.parameters = parameters;
-    newTask.id = this.generateUniqueId();
+    newTask.id = Symbol(this.tasks.length);
 
     this.tasks.push(newTask);
 
     return newTask.id;
   }
 
-  async run(task: Task.Callable) {
+  async run(taskRef: Task.TaskRef) {
+    const task = this.findTask(taskRef);
+
+    if (task === undefined) {
+      throw new Error(`Task ${taskRef.name} not found`);
+    }
+
     if (task.status !== "idle") {
       return;
     }
@@ -44,6 +51,7 @@ class TaskManager {
       task.status = "success";
     } catch (err) {
       task.status = "failure";
+      throw err;
     }
   }
 }
diff --git a/frontend/src/modules/task/task.d.ts b/frontend/src/modules/task/task.d.ts
index ae8f785e2..4c7e2add1 100644
--- a/frontend/src/modules/task/task.d.ts
+++ b/frontend/src/modules/task/task.d.ts
@@ -5,13 +5,13 @@ declare namespace Task {
   type AnyCallable = (...args: any[]) => Promise<void>;
   export type Callable<T extends AnyCallable = AnyCallable> = T & {
     parameters: Parameters<T>;
-    id: string;
+    id: symbol;
     status: Status;
   };
 
-  export interface Task {
+  export interface TaskRef {
     name: string;
-    callableId: string;
+    callableId: symbol;
     description?: string;
   }
 
diff --git a/frontend/src/modules/task/utilities.ts b/frontend/src/modules/task/utilities.ts
index 9f8b8d1e5..8acb95a74 100644
--- a/frontend/src/modules/task/utilities.ts
+++ b/frontend/src/modules/task/utilities.ts
@@ -1,3 +1,4 @@
+import { LOG } from "@/utilities/console";
 import taskManager from ".";
 import { GroupName } from "./group";
 
@@ -5,17 +6,24 @@ export function createTask<T extends Task.AnyCallable>(
   name: string,
   callable: T,
   ...parameters: Parameters<T>
-): Task.Task {
+): Task.TaskRef {
   const callableId = taskManager.create(callable, parameters);
 
+  LOG("info", "task created", name);
+
   return {
     name,
     callableId,
   };
 }
 
-export function dispatchTask(task: Task.Task[], group: GroupName) {
-  // TODO
+export function dispatchTask(tasks: Task.TaskRef[], group: GroupName) {
+  setTimeout(async () => {
+    for (const ref of tasks) {
+      LOG("info", "dispatching task", ref.name);
+      await taskManager.run(ref);
+    }
+  });
 }
 
 export function createAndDispatchTask<T extends Task.AnyCallable>(
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