import type * as lambda from "aws-lambda";
import * as Context from "effect/Context";
import * as Effect from "effect/Effect";
import * as Stream from "effect/Stream";
import type { Queue } from "./Queue.ts";

export type SQSRecord = lambda.SQSRecord;

export interface MessagesProps extends QueueEventSourceProps {
  /**
   * Time in seconds for long polling when using the process (run) path.
   * @default 20
   */
  waitTimeSeconds?: number;
  /**
   * Maximum number of messages to receive per poll when using the process (run) path.
   * @default 10
   */
  maxNumberOfMessages?: number;
}

export const messages = <Q extends Queue>(
  queue: Q,
  props: MessagesProps = {},
) => ({
  subscribe: <Req = never>(
    process: (
      stream: Stream.Stream<SQSRecord>,
    ) => Effect.Effect<void, never, Req>,
  ) => QueueEventSource.use((source) => source(queue, props, process)),
});

export class QueueEventSource extends Context.Service<
  QueueEventSource,
  QueueEventSourceService
>()("AWS.SQS.QueueEventSource") {}

export interface QueueEventSourceProps {
  /**
   * The maximum number of records in each batch that Lambda pulls from the queue.
   * @default 10
   */
  batchSize?: number;
  /**
   * The maximum amount of time, in seconds, that Lambda spends gathering records before invoking the function.
   * @default 0
   */
  maximumBatchingWindowInSeconds?: number;
}

export type QueueEventSourceService = <Req = never>(
  bucket: Queue,
  props: MessagesProps,
  process: (
    stream: Stream.Stream<SQSRecord>,
  ) => Effect.Effect<void, never, Req>,
) => Effect.Effect<void, never, never>;