import { Mail } from "../mail.ts";
import { AwsContext } from "./context.ts";
import { AwsMailRetriever } from "./retriever.ts";

export interface AwsServiceSetupOptions {
  receiveCallback: (mail: Mail) => Promise<void>;
}

interface Setup {
  receiveCallback: (mail: Mail) => Promise<void>;
  retriever: AwsMailRetriever;
  liveMailRecyclerAborter: AbortController;
}

export class AwsService implements Disposable {
  private _setup: Setup | null = null;

  constructor(private readonly aws: AwsContext) {}

  setup(options: AwsServiceSetupOptions): Disposable {
    if (this._setup != null) {
      // TODO: Better error.
      throw new Error("Aws service has already been set up.");
    }
    const { receiveCallback } = options;
    const liveMailRecyclerAborter = new AbortController();
    const retriever = new AwsMailRetriever(this.aws, receiveCallback);

    Deno.cron("live-mail-recycler", "0 */6 * * *", {
      signal: liveMailRecyclerAborter.signal,
    }, () => {
      retriever.recycleLiveMails();
    });

    this._setup = {
      receiveCallback,
      retriever,
      liveMailRecyclerAborter,
    };

    return this;
  }

  [Symbol.dispose]() {
    if (this._setup == null) return;
    this._setup.liveMailRecyclerAborter.abort("Aws service is being disposed.");
  }
}