import { SimplePool } from 'nostr-tools'
import type { Filter } from 'nostr-tools'
import type { Event } from 'nostr-tools'

/**
 * Subscription interface matching nostr-tools 2.x API
 */
export interface Subscription {
  on(event: 'event', callback: (event: Event) => void): void
  on(event: 'eose', callback: () => void): void
  unsub(): void
}

/**
 * Type for SimplePool with subscribe method (for backward compatibility)
 * Note: SimplePool already has subscribe method, this is just for type compatibility
 */
export type SimplePoolWithSub = SimplePool

/**
 * Helper to create a subscription compatible with the old API
 */
export function createSubscription(
  pool: SimplePool,
  relays: string[],
  filters: Filter[]
): Subscription {
  const events: Event[] = []
  let eoseReceived = false
  const eventCallbacks: Array<(event: Event) => void> = []
  const eoseCallbacks: Array<() => void> = []

  const subscription = pool.subscribe(
    relays,
    filters[0] || {},
    {
      onevent: (event: Event) => {
        events.push(event)
        eventCallbacks.forEach((cb) => cb(event))
      },
      oneose: () => {
        eoseReceived = true
        eoseCallbacks.forEach((cb) => cb())
      },
    }
  )

  const subscriptionWrapper: Subscription = {
    on(event: 'event' | 'eose', callback: ((event: Event) => void) | (() => void)): void {
      if (event === 'event') {
        const eventCb = callback as (event: Event) => void
        eventCallbacks.push(eventCb)
        // Emit any events that were already received
        events.forEach((e) => eventCb(e))
      } else if (event === 'eose') {
        const eoseCb = callback as () => void
        if (eoseReceived) {
          eoseCb()
        } else {
          eoseCallbacks.push(eoseCb)
        }
      }
    },
    unsub(): void {
      subscription.close()
    },
  }
  return subscriptionWrapper
}