// SPEC: PJ2026-0106050514 Workbench实时运行面 draft-2026-06-30-p0-1297-spec-first.
// Responsibility: Async queue and bounded worker pool. Mechanically migrated from OpenCode opencode/src/util/queue.ts.

export class AsyncQueue<T> implements AsyncIterable<T> {
  private queue: T[] = [];
  private resolvers: Array<(value: T) => void> = [];

  push(item: T): void {
    const resolve = this.resolvers.shift();
    if (resolve) resolve(item);
    else this.queue.push(item);
  }

  async next(): Promise<T> {
    if (this.queue.length > 0) return this.queue.shift() as T;
    return new Promise((resolve) => this.resolvers.push(resolve));
  }

  async *[Symbol.asyncIterator](): AsyncIterator<T> {
    while (true) yield await this.next();
  }
}

export async function work<T>(concurrency: number, items: T[], fn: (item: T) => Promise<void>): Promise<void> {
  const pending = [...items];
  await Promise.all(
    Array.from({ length: concurrency }, async () => {
      while (true) {
        const item = pending.pop();
        if (item === undefined) return;
        await fn(item);
      }
    })
  );
}