Machine Coding: AI-IDE Task Scheduler

Problem Statement

In high-performance IDEs and AI-assisted editors, managing background tasks is critical. You need to implement a Priority Task Queue with Concurrency Control.

Your task is to create a TaskScheduler class that can handle multiple tasks with different priorities (High, Medium, Low). The scheduler should limit the number of concurrently running tasks to avoid slowing down the editor's main thread or overwhelming the AI service APIs.

Requirements

1. Concurrency Limit: The scheduler should accept a maxConcurrency value in its constructor.
2. Priority Levels: Tasks are added with a priority: 0 (High), 1 (Medium), and 2 (Low). High-priority tasks should always run before lower-priority ones.
3. Task Execution: Tasks are asynchronous functions that return a Promise.
4. Result Management: The scheduler should return a promise that resolves with the task's result when it completes.

Example

const scheduler = new TaskScheduler(2); // Max 2 tasks at a time

const task1 = () => new Promise(res => setTimeout(() => res('Task 1'), 1000));
const task2 = () => new Promise(res => setTimeout(() => res('Task 2'), 500));

scheduler.addTask(task1, 1).then(console.log); // Medium priority
scheduler.addTask(task2, 0).then(console.log); // High priority

Constraints

• The number of active promises must never exceed maxConcurrency.
• If a High priority task enters the queue while the scheduler is full, it must be the next task to run once a slot opens up.