story-research-zapwall/lib/payment.ts

import { nostrService } from './nostr'
import { waitForArticlePayment as waitForArticlePaymentHelper } from './paymentPolling'
import { resolveArticleInvoice } from './invoiceResolver'
import { PLATFORM_COMMISSIONS, calculateArticleSplit } from './platformCommissions'
import type { Article } from '@/types/nostr'
import type { AlbyInvoice } from '@/types/alby'

export interface PaymentRequest {
  article: Article
  userPubkey: string
}

export interface PaymentResult {
  success: boolean
  invoice?: AlbyInvoice
  paymentHash?: string
  error?: string
}

/**
 * Payment service integrating Alby/WebLN Lightning payments with Nostr articles
 */
export class PaymentService {
  /**
   * Create a Lightning invoice for an article payment
   * First checks if author has created an invoice in the event tags, otherwise creates a new one
   */
  private validateArticleAmount(zapAmount: number): { valid: boolean; error?: string } {
    const expectedAmount = PLATFORM_COMMISSIONS.article.total
    if (zapAmount !== expectedAmount) {
      return {
        valid: false,
        error: `Invalid article payment amount: ${zapAmount} sats. Expected ${expectedAmount} sats (700 to author, 100 commission)`,
      }
    }
    return { valid: true }
  }

  private validateInvoiceAmount(invoice: AlbyInvoice): { valid: boolean; error?: string } {
    const split = calculateArticleSplit()
    if (invoice.amount !== split.total) {
      return {
        valid: false,
        error: `Invoice amount mismatch: ${invoice.amount} sats. Expected ${split.total} sats (${split.author} to author, ${split.platform} commission)`,
      }
    }
    return { valid: true }
  }

  async createArticlePayment(request: PaymentRequest): Promise<PaymentResult> {
    try {
      const amountValidation = this.validateArticleAmount(request.article.zapAmount)
      if (!amountValidation.valid) {
        return { success: false, error: amountValidation.error ?? 'Invalid amount' }
      }

      const invoice = await resolveArticleInvoice(request.article)
      const invoiceValidation = this.validateInvoiceAmount(invoice)
      if (!invoiceValidation.valid) {
        return { success: false, error: invoiceValidation.error ?? 'Invalid invoice amount' }
      }

      await nostrService.createZapRequest(request.article.pubkey, request.article.id, request.article.zapAmount)

      return {
        success: true,
        invoice,
        paymentHash: invoice.paymentHash,
      }
    } catch (error) {
      console.error('Payment creation error:', error)
      return {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to create payment',
      }
    }
  }

  /**
   * Check if payment for an article has been completed
   */
  async checkArticlePayment(
    _paymentHash: string,
    articleId: string,
    articlePubkey: string,
    amount: number,
    userPubkey?: string
  ): Promise<boolean> {
    try {
      // With Alby/WebLN, we rely on zap receipts for payment verification
      // since WebLN doesn't provide payment status checking
      const zapReceiptExists = await nostrService.checkZapReceipt(
        articlePubkey,
        articleId,
        amount,
        userPubkey
      )

      return zapReceiptExists
    } catch (error) {
      console.error('Payment check error:', error)
      return false
    }
  }

  /**
   * Wait for payment completion with polling
   * After payment is confirmed, sends private content to the user
   */
  waitForArticlePayment(
    paymentHash: string,
    articleId: string,
    articlePubkey: string,
    amount: number,
    recipientPubkey: string,
    timeout: number = 300000 // 5 minutes
  ): Promise<boolean> {
    return waitForArticlePaymentHelper(
      paymentHash,
      articleId,
      articlePubkey,
      amount,
      recipientPubkey,
      timeout
    )
  }

  /**
   * Get payment URL for display/QR code generation
   */
  async getPaymentUrl(request: PaymentRequest): Promise<string | null> {
    try {
      const result = await this.createArticlePayment(request)

      if (result.success && result.invoice) {
        // Return Lightning URI format
        return `lightning:${result.invoice.invoice}`
      }

      return null
    } catch (error) {
      console.error('Get payment URL error:', error)
      return null
    }
  }
}

export const paymentService = new PaymentService()