import Queue from './queue.js'

export default class AsyncGeneratorQueue<T> implements Queue<T> {
  #buffer: T[] = []
  #resolveQueue: ((value: T) => void)[] = []
  #finished = false

  add(value: T): void {
    if (this.#resolveQueue.length > 0) {
      // If there's a pending consumer, resolve immediately
      const resolve = this.#resolveQueue.shift()!
      resolve(value)
    } else {
      // Otherwise, add to the buffer
      this.#buffer.push(value)
    }
  }

  async *consume(): AsyncGenerator<T> {
    while (
      !this.#finished ||
      this.#resolveQueue.length > 0 ||
      this.#buffer.length > 0
    ) {
      if (this.#buffer.length > 0) {
        yield this.#buffer.shift()! // Yield available values
      } else {
        yield await new Promise<T>((resolve) => this.#resolveQueue.push(resolve))
      }
    }
  }
  disposeAsync(): Promise<void> {
    this.#finished = true
    return Promise.resolve()
  }
}