import { Injectable } from '@angular/core';

import { buildAttachmentChunkAckKey } from '../../domain/logic/attachment-chunk-ack.rules';

@Injectable({ providedIn: 'root' })
export class AttachmentChunkAckService {
  private readonly waiters = new Map<string, () => void>();

  waitForAck(
    messageId: string,
    fileId: string,
    index: number,
    timeoutMs = 60_000
  ): Promise<void> {
    const key = buildAttachmentChunkAckKey(messageId, fileId, index);

    return new Promise((resolve, reject) => {
      const timer = setTimeout(() => {
        this.waiters.delete(key);
        reject(new Error('attachment chunk ack timeout'));
      }, timeoutMs);

      this.waiters.set(key, () => {
        clearTimeout(timer);
        this.waiters.delete(key);
        resolve();
      });
    });
  }

  resolveAck(messageId: string, fileId: string, index: number): void {
    this.waiters.get(buildAttachmentChunkAckKey(messageId, fileId, index))?.();
  }

  cancelPendingForFile(messageId: string, fileId: string): void {
    const prefix = `${messageId}:${fileId}:`;

    for (const [key, resolve] of this.waiters) {
      if (!key.startsWith(prefix)) {
        continue;
      }

      resolve();
      this.waiters.delete(key);
    }
  }
}