import type { Event } from 'nostr-tools'
import { SimplePool } from 'nostr-tools'
import { createSubscription } from '@/types/nostr-tools-extended'
import { getPrimaryRelaySync } from './config'

function createZapFilters(targetPubkey: string, targetEventId: string, userPubkey: string): Array<{
  kinds: number[]
  '#p': string[]
  '#e': string[]
  authors: string[]
}> {
  return [
    {
      kinds: [9735], // Zap receipt
      '#p': [targetPubkey],
      '#e': [targetEventId],
      authors: [userPubkey], // Filter by the payer's pubkey
    },
  ]
}

async function isValidZapReceipt(
  params: {
    event: Event
    targetEventId: string
    targetPubkey: string
    userPubkey: string
    amount: number
  }
): Promise<boolean> {
  // Import verification service dynamically to avoid circular dependencies
  const { zapVerificationService } = await import('./zapVerification')

  return zapVerificationService.verifyZapReceiptForArticle({
    zapReceipt: params.event,
    articleId: params.targetEventId,
    articlePubkey: params.targetPubkey,
    userPubkey: params.userPubkey,
    expectedAmount: params.amount,
  })
}

/**
 * Check if user has paid for an article by looking for zap receipts
 */
function handleZapReceiptEvent(
  params: {
    event: Event
    targetEventId: string
    targetPubkey: string
    userPubkey: string
    amount: number
    finalize: (value: boolean) => void
    resolved: { current: boolean }
  }
): void {
  if (params.resolved.current) {
    return
  }
  void isValidZapReceipt({
    event: params.event,
    targetEventId: params.targetEventId,
    targetPubkey: params.targetPubkey,
    userPubkey: params.userPubkey,
    amount: params.amount,
  }).then((isValid) => {
    if (isValid) {
      params.finalize(true)
    }
  })
}

export function checkZapReceipt(
  params: {
    pool: SimplePool
    targetPubkey: string
    targetEventId: string
    amount: number
    userPubkey: string
  }
): Promise<boolean> {
  if (!params.pool) {
    return Promise.resolve(false)
  }

  return new Promise<boolean>((resolve) => {
    let resolved = false
    const relayUrl = getPrimaryRelaySync()
    const sub = createSubscription(params.pool, [relayUrl], createZapFilters(params.targetPubkey, params.targetEventId, params.userPubkey))

    const finalize = (value: boolean): void => {
      if (resolved) {
        return
      }
      resolved = true
      sub.unsub()
      resolve(value)
    }

    const resolvedRef = { current: resolved }
    sub.on('event', (event: Event): void => {
      handleZapReceiptEvent({
        event,
        targetEventId: params.targetEventId,
        targetPubkey: params.targetPubkey,
        userPubkey: params.userPubkey,
        amount: params.amount,
        finalize,
        resolved: resolvedRef,
      })
    })

    const end = (): void => {
      finalize(false)
    }
    sub.on('eose', end)
    setTimeout(end, 3000)
  })
}