/**
 * 消息发送队列（限流）
 *
 * 原始 Dart: lib/core/net/message_queue.dart
 *
 * 业务行为：
 *   - 入队消息按 `intervalMs` 间隔逐条发送（默认 1000ms）
 *   - 消费者可声明每条消息是否成功消费；不成功则重新入队
 *   - 队列可在任意时刻清空（dispose）
 */
import { Logger } from "@/utils";

export type MessageConsumer = (content: string) => boolean | Promise<boolean>;

const log = new Logger("MessageQueue");

export class MessageQueue {
  private queue: string[] = [];
  private timer: ReturnType<typeof setTimeout> | null = null;
  private disposed = false;
  private consumer: MessageConsumer | null = null;

  constructor(private readonly intervalMs = 1000) {}

  /** 注册消费者（消费者必须能处理失败/重试）。 */
  setConsumer(consumer: MessageConsumer): void {
    this.consumer = consumer;
  }

  enqueue(content: string): void {
    if (this.disposed) return;
    this.queue.push(content);
    if (!this.timer) this.scheduleNext();
  }

  private async attemptSend(next: string): Promise<void> {
    if (!this.consumer) {
      this.queue.unshift(next);
      return;
    }
    let ok = false;
    try {
      ok = await this.consumer(next);
    } catch (e) {
      log.error({ err: e }, "consumer error");
      ok = false;
    }
    if (!ok) {
      // 消费失败，放回队首等待下次
      this.queue.unshift(next);
    }
  }

  private scheduleNext(): void {
    if (this.disposed) return;
    const next = this.queue.shift();
    if (next === undefined) {
      this.timer = null;
      return;
    }
    this.timer = setTimeout(() => {
      void this.attemptSend(next).finally(() => this.scheduleNext());
    }, this.intervalMs);
  }

  clear(): void {
    this.queue = [];
  }

  dispose(): void {
    this.disposed = true;
    this.clear();
    if (this.timer) {
      clearTimeout(this.timer);
      this.timer = null;
    }
  }
}