import { priorityQueue, type AsyncPriorityQueue } from 'async';
import { withTimeout } from './utils.js';

export class TaskProcessor {
    private maxParallelTasks: number;
    private taskQueue: AsyncPriorityQueue<() => Promise<void>>;

    constructor(maxParallelTasks: number) {
        this.maxParallelTasks = maxParallelTasks;
        this.taskQueue = priorityQueue(function (task, callback) {
            task().then(() => callback(), (e) => callback(e));
        }, this.maxParallelTasks);
        this.taskQueue.error((e) => {
            console.log("Error in task queue task: " + e);
        })
        console.log(`Task processor created with a maximum of ${maxParallelTasks} parallel tasks`);
    }

    schedule(task: () => Promise<any>, timeoutMs: number, priority = 100): Promise<void> {
        return new Promise((resolve, reject) => {
            const wrappedTask = () => withTimeout(task(), timeoutMs);
            this.taskQueue.push(wrappedTask, priority, (err) => {
                if (err) {
                    reject(err);
                } else {
                    resolve();
                }
            });
        })
    }

    unsaturated(): Promise<void> {
        return this.taskQueue.unsaturated();
    }
}