import Emittery from "emittery";

//needed to pass information on wether or not the promise has been aborted witout 'this'
class AbortableEmittery extends Emittery {
  public aborted = false;

  abort() {
    this.aborted = true;
    this.emit("abort");
  }
}

export default class AbortablePromise<T> extends Promise<T | null> {
  private emitter: AbortableEmittery;

  constructor(
    make_generator: (
      await_or_abort: (
        promise: Promise<any>,
        on_abort: () => Promise<unknown>
      ) => Promise<unknown>
    ) => AsyncGenerator
  ) {
    const emitter = new AbortableEmittery();
    const await_or_abort = (
      promise: Promise<any>,
      on_abort: () => Promise<unknown>
    ) => {
      return new Promise((resolve, reject) => {
        let resolved = false;
        emitter.on("abort", () => {
          if (!resolved) {
            on_abort();
            resolve(null);
            resolved = true;
          }
        });
        promise
          .then((result) => {
            if (!resolved) {
              resolve(result);
              resolved = true;
            }
          })
          .catch(reject);
      });
    };
    super(async (resolve, reject) => {
      let step_value;
      const generator = make_generator(await_or_abort);
      do {
        if (emitter.aborted) {
          resolve(null);
          return;
        }
        step_value = await generator.next();
      } while (!step_value.done);
      resolve(step_value.value);
    });
    this.emitter = emitter;
  }

  abort() {
    this.emitter.abort();
  }
}

// const sleep = promisify((timeout: number, callback: (...args: any[]) => void) =>
// 	setTimeout(callback, timeout)
// );

// const a = new AbortablePromise(async function* () {
// 	yield await sleep(1000);
// 	console.log("awaited 100");
// 	yield await sleep(2000);
// 	console.log("awaited 200");
// 	yield await sleep(3000);
// 	console.log("awaited 300");
// });

// setTimeout(() => a.abort(), 1500);

// const b = new AbortablePromise(async function* (await_or_abort) {
//   const ping = await deferedSpawn("ping", ["8.8.8.8"]);
//   while (true) {
//     console.log(
//       await await_or_abort(ping.waitForNextData(), () => {
//         ping.kill();
//       })
//     );
//     yield;
//   }
// });

// setTimeout(() => b.abort(), 5000);