// server/supabase/functions/stripe-webhook/index.ts
// Stripe Webhook 핸들러 — checkout 완료, 구독 갱신/취소 등 이벤트 처리.
// Supabase 대시보드 → Functions → stripe-webhook 의 verify_jwt를 false로 설정해야 함
// (Stripe는 JWT 없이 호출, 대신 signature로 검증).
//
// 환경변수:
//   STRIPE_SECRET_KEY
//   STRIPE_WEBHOOK_SECRET (Stripe 대시보드에서 발급)

import { createServiceRoleClient } from '../_shared/quota.ts'

interface StripeEvent {
  id: string
  type: string
  data: {
    object: Record<string, unknown>
  }
}

async function verifyStripeSignature(payload: string, signature: string, secret: string): Promise<boolean> {
  // 단순화: 본 스캐폴딩에서는 signature 검증 logic placeholder.
  // 정식 구현은 Stripe SDK의 stripe.webhooks.constructEvent 사용 또는
  // HMAC-SHA256으로 직접 검증.
  // https://stripe.com/docs/webhooks/signatures
  return Boolean(signature && secret && payload)
}

// @ts-expect-error — Deno 런타임 전역
Deno.serve(async (req: Request) => {
  if (req.method !== 'POST') {
    return new Response('Method not allowed', { status: 405 })
  }

  // @ts-expect-error — Deno.env
  const webhookSecret = Deno.env.get('STRIPE_WEBHOOK_SECRET') ?? ''
  if (!webhookSecret) {
    return new Response('Webhook secret not configured', { status: 503 })
  }

  const signature = req.headers.get('stripe-signature') ?? ''
  const payload = await req.text()

  const valid = await verifyStripeSignature(payload, signature, webhookSecret)
  if (!valid) {
    return new Response('Invalid signature', { status: 400 })
  }

  let event: StripeEvent
  try {
    event = JSON.parse(payload) as StripeEvent
  } catch {
    return new Response('Invalid JSON', { status: 400 })
  }

  const serviceClient = createServiceRoleClient()

  try {
    switch (event.type) {
      case 'checkout.session.completed': {
        const session = event.data.object as {
          customer: string
          subscription: string
          metadata?: { user_id?: string; tier?: string }
        }
        const userId = session.metadata?.user_id
        const tier = session.metadata?.tier
        if (userId && tier) {
          await serviceClient.from('subscriptions').upsert({
            user_id: userId,
            stripe_customer_id: session.customer,
            stripe_subscription_id: session.subscription,
            tier,
            status: 'active'
          })
        }
        break
      }

      case 'customer.subscription.updated':
      case 'customer.subscription.created': {
        const sub = event.data.object as {
          id: string
          customer: string
          status: string
          current_period_start?: number
          current_period_end?: number
          cancel_at?: number | null
        }
        await serviceClient
          .from('subscriptions')
          .update({
            status: sub.status,
            current_period_start: sub.current_period_start
              ? new Date(sub.current_period_start * 1000).toISOString()
              : null,
            current_period_end: sub.current_period_end
              ? new Date(sub.current_period_end * 1000).toISOString()
              : null,
            cancel_at: sub.cancel_at ? new Date(sub.cancel_at * 1000).toISOString() : null
          })
          .eq('stripe_subscription_id', sub.id)
        break
      }

      case 'customer.subscription.deleted': {
        const sub = event.data.object as { id: string }
        await serviceClient
          .from('subscriptions')
          .update({ tier: 'free', status: 'canceled' })
          .eq('stripe_subscription_id', sub.id)
        break
      }

      default:
        // 기타 이벤트는 무시
        break
    }

    return new Response(JSON.stringify({ received: true }), {
      status: 200,
      headers: { 'Content-Type': 'application/json' }
    })
  } catch (err) {
    const message = err instanceof Error ? err.message : 'Unknown error'
    return new Response(JSON.stringify({ error: message }), {
      status: 500,
      headers: { 'Content-Type': 'application/json' }
    })
  }
})