rateLimiter.ts

import type { Duration, Scope } from "effect"
import { Effect, SynchronizedRef } from "effect"

export const make = (limit: number, window: Duration.DurationInput): Effect.Effect<
  <A, E, R>(effect: Effect.Effect<A, E, R>) => Effect.Effect<A, E, R>,
  never,
  Scope.Scope
> =>
  Effect.gen(function*(_) {
    const scope = yield* _(Effect.scope)
    const semaphore = yield* _(Effect.makeSemaphore(limit))
    const ref = yield* _(SynchronizedRef.make(false))
    const reset = SynchronizedRef.updateEffect(ref, (running) =>
      running ? Effect.succeed(true) : Effect.sleep(window).pipe(
        Effect.zipRight(SynchronizedRef.set(ref, false)),
        Effect.zipRight(semaphore.releaseAll),
        Effect.forkIn(scope),
        Effect.interruptible,
        Effect.as(true)
      ))
    const take = Effect.zipRight(semaphore.take(1), reset)
    return (effect) =>
      Effect.zipRight(take, effect)
  })