import type { Event } from 'nostr-tools'
import { generateReviewTipHashId } from '../hashIdGenerator'
import type { ExtractedReviewTip } from './types'
import { readAmountSats, readPaymentHash, readPayerPubkeyFromZapReceipt, readTagValue, readZapReceiptKind } from './utils'

export async function extractReviewTipFromEvent(event: Event): Promise<ExtractedReviewTip | null> {
  if (event.kind !== 9735 || readZapReceiptKind(event) !== 'review_tip') {
    return null
  }

  const extracted = readReviewTipFields(event)
  if (!extracted) {
    return null
  }

  const id = await generateReviewTipHashId(extracted)
  return { type: 'review_tip', id, ...extracted, eventId: event.id }
}

function readReviewTipFields(event: Event): Omit<ExtractedReviewTip, 'type' | 'id' | 'eventId'> | null {
  const payerPubkey = readPayerPubkeyFromZapReceipt(event)
  const amount = readAmountSats(event)
  const paymentHash = readPaymentHash(event)
  const reviewerPubkey = readTagValue(event, 'reviewer') ?? readTagValue(event, 'p')
  const authorPubkey = readTagValue(event, 'author')
  const articleId = readTagValue(event, 'article')
  const reviewId = readTagValue(event, 'review_id') ?? readTagValue(event, 'e')

  const required = { payerPubkey, reviewerPubkey, authorPubkey, articleId, reviewId, paymentHash }
  if (!hasRequiredReviewTipFields(required) || amount === undefined) {
    console.error('[metadataExtractor] Invalid review_tip zap receipt: missing required fields', { eventId: event.id })
    return null
  }

  return {
    payerPubkey: required.payerPubkey,
    reviewerPubkey: required.reviewerPubkey,
    authorPubkey: required.authorPubkey,
    articleId: required.articleId,
    reviewId: required.reviewId,
    amount,
    paymentHash: required.paymentHash,
  }
}

function hasRequiredReviewTipFields(values: {
  payerPubkey: string | undefined
  reviewerPubkey: string | undefined
  authorPubkey: string | undefined
  articleId: string | undefined
  reviewId: string | undefined
  paymentHash: string | undefined
}): values is {
  payerPubkey: string
  reviewerPubkey: string
  authorPubkey: string
  articleId: string
  reviewId: string
  paymentHash: string
} {
  const requiredKeys: ReadonlyArray<keyof typeof values> = [
    'payerPubkey',
    'reviewerPubkey',
    'authorPubkey',
    'articleId',
    'reviewId',
    'paymentHash',
  ]
  return requiredKeys.every((key) => isNonEmptyString(values[key]))
}

function isNonEmptyString(value: unknown): value is string {
  return typeof value === 'string' && value.length > 0
}