import type { Event } from 'nostr-tools'

export function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === 'object' && value !== null && !Array.isArray(value)
}

export function readPayerPubkeyFromZapReceipt(event: Event): string | undefined {
  const descriptionTag = readTagValue(event, 'description')
  if (!descriptionTag) {
    return undefined
  }
  try {
    const parsed: unknown = JSON.parse(descriptionTag)
    return isRecord(parsed) && typeof parsed.pubkey === 'string' ? parsed.pubkey : undefined
  } catch (e) {
    console.error('[metadataExtractor] Error parsing zap receipt description tag:', e)
    return undefined
  }
}

export function firstString(...values: unknown[]): string | undefined {
  for (const value of values) {
    if (typeof value === 'string') {
      return value
    }
  }
  return undefined
}

export function firstNumber(...values: unknown[]): number | undefined {
  for (const value of values) {
    if (typeof value === 'number') {
      return value
    }
  }
  return undefined
}

export function readTagValue(event: Event, key: string): string | undefined {
  return event.tags.find((tag) => tag[0] === key)?.[1]
}

export function readZapReceiptKind(event: Event): string | undefined {
  if (event.kind !== 9735) {
    return undefined
  }
  return readTagValue(event, 'kind_type')
}

export function readAmountSats(event: Event): number | undefined {
  const amountTag = readTagValue(event, 'amount')
  if (!amountTag) {
    return undefined
  }
  const millisats = Number.parseInt(amountTag, 10)
  if (Number.isNaN(millisats)) {
    return undefined
  }
  return millisats / 1000
}

export function readPaymentHash(event: Event): string {
  return readTagValue(event, 'payment_hash') ?? event.id
}

export function resolveSponsoringArticleId(params: { articleTag: string | undefined; eTag: string | undefined }): string | undefined {
  return params.articleTag ?? params.eTag
}